What causes that howling sound in PA systems? | HowStuffWorks What causes that howling sound in PA systems? NEXT PAGENEXT A simple PA (public address) system consists of a microphone , an amplifier and one or more speakers . Whenever you have those three components, you have the potential for feedback. Feedback occurs when the sound from the speakers makes it back into the microphone and is re-amplified and sent through the speakers again, like this: Imagine, for example, that you place the microphone in front of the speaker as shown. Now you tap on the microphone. The sound of the tap goes through the amplifier, comes out the speaker, re-enters the microphone, etc. This loop happens so quickly that it creates its own frequency, which we hear as a howling sound. The distance between the mike and the speakers has a lot to do with the frequency of the howling, because that distance controls how quickly the sound can loop through the system. Up Next Are premium audio cables worth the investment? You can actually try this out on your computer if your computer has speakers and a microphone.

In Windows, you need to enable the microphone and speakers using the volume control (which you can access by double clicking on the speaker icon in the system tray). Make sure that in this dialog the microphone and speakers are not muted and are at maximum volume (if the microphone control is not visible, select it in Properties). If you have it set up right, you should be able to tap the microphone and hear it in the speakers. Now place the microphone near the speakers and turn up the speaker volume until you hear the feedback. Try changing the distance between the mike and speakers and see what effect that has on things. Be sure not to try this at 2 a.m. when other family members are sleeping, and also be sure to put the dog out... If you are setting up a sound system and want to avoid feedback, there are a few general rules that can help you avoid the problem: Make sure the speakers are in front of the microphone and pointing away from the microphone. If the speakers are behind the microphone, then feedback is nearly guaranteed. Use a unidirectional microphone. Place the microphone close to the person who is speaking/performing. If you have access to an equalizer, dampen the frequencies where feedback is occurring.

These links will help you learn more: How To Stop Microphone Squeal And Feedback Got A Problem With Microphone Squeal? Here's How To Fix It... Why you get microphone feedback Microphone squeal is caused by feedback. Feedback happens when the microphone picks up the output sound from your speakers which it then re-amplifies causing a loop. The loop is caused by the microphone picking up the original amplified sound and amplifying it again, then again, then again, then again...until the sound can't be amplified any more and something has to give. Feedback has the capacity to blow your speakers or amplifier, although it has to be said that most modern amplifiers these days have protection built in to protect it from any lasting damage. Nevertheless, feedback is a serious problem. Even if it doesn't blow your amplifier or your speakers, it WILL drive you (and your audience) to despair. Feedback usually presents itself in the form of a bassy boom or a high pitched ear-piercing sqeal depending on whether your microphone is picking up low frequencies or high frequencies. What your microphone should and should not pick up The only sound your microphone should pick up is your voice.

It should then send your voice to your amplifier which, in turn, amplifies the sound and puts it out through your speakers. But if your microphone picks up any other sounds other than your voice, especially sounds coming from your speakers, it will then amplify and re-amplify those sounds in a never ending loop until something gives (usually your audiences ears)! Feedback is a common problem when singing live. It's more common in small venues where the microphone can easily pick up the sound from the main PA speakers. This is because in small venues you will usually have your main PA speakers fairly close to you. Your microphone picks up the sound from the speakers and, hey presto, the microphone starts to squeel and you have a feedback problem! Also generally the more microphones you have on a stage at any one time switched on, the more feedback you are likely to get. This is because microphones will often feedback with each other. How to cure microphone feedback - Tip 1 Fortunately there are a couple of ways to reduce microphone feedback when singing live. First, switch off microphones when they are not in use. For example, if the compere has a microphone he uses to introduce your act, switch it off as soon as he's introduced you.

If any others in your band are NOT singing a part in the song that's curently being performed, tell them to switch off their microphone during that song. A microphone which is not in use but switched on is like a sitting duck - it's just waiting to pick up any rogue feedback frequencies and cause you problems. Rule number 1...if it's not in use, switch it off! How to cure microphone feedback - Tip 2 Next, when singing live, keep your microphone as close to your lips as possible (but without actually touching your lips). Keeping your microphone close up to your mouth when singing live will allow you to reduce the overall volume of your microphone slightly at the mixing desk end and this is often just enough to stop the feedback. I often see singers holding their microphone 6 inches to a foot away from their mouth when singing...and then they can't figure out why they are getting so much feedback! Holding a microphone far away from your mouth is only possible when you have an exceptionally big powerful voice (because if you DO have a big powerful voice, then you won't need so much volume on your microphone and you won't have feedback problems anyway).

But most male and female singers do not have a big powerful operatic type voice...more than 90% of singers have normal strength voices. This means that in most cases the microphone needs to be set at a reasonably high volume level to pick up their voice...and that means feedback can be a problem. So if you find yourself in a live music venue where the EQ hasn't been set by a professional sound engineer specially to suit that room prior to you singing in it, then keep the microphone closer to your lips. This will allow you to reduce the volume of your mic a little and therefore help reduce any feedback. Just to be clear on this point (because I know you've probably watched singers on TV holding the microphone quite far away from their mouth so maybe wonder why I'm telling you that you can't do this), if you are in a professional recording studio, a TV studio, or some theatres, you can often get away with holding a microphone at an arms length but only because the acoustics in these places have been professionally set by professional sound engineers and the speakers have been carefully placed and EQ'd so that feedback is not a problem.

But you are not in the same venue every day and even if you are, your PA has not been set up by a professional sound engineer. So for everyday live music type venues that you will be singing in with your own PA system, keep your microphone fairly close to your mouth (except when you hit those big high notes of course) or feedback WILL be a problem. How to cure microphone feedback - Tip 3 Another way to reduce feedback is to adjust the EQ on your microphone channel and take a little off the top-end (i.e. turn down the treble). This is because most microphone feedback tends to occur more commonly in the upper/treble frequencies (although bass feedback does happen too). Bass feedback is more of a loud booming sound whereas high frequency feedback is more of a high pitched squeal. Just be careful when using your EQ to cut frequencies though. If you take too much treble away from your microphone you could end up with a muffled vocal sound. Take too much bass frequencies away and you may be left with a tinny or thin sound to your vocals... More expensive mixing desks have more comprehensive EQ settings.

With a really good mixing desk you can scroll through the frequencies till you find where the feedback is occuring and "cut" that frequency without affecting any of the other frequencies - this is without doubt the best way to cure feedback problems. However this is more the realm of professional sound engineers so it's probably not the sort of thing a normal singer would want to spend time learning to do - it is quite an involved process with quite a large learning curve, although in my opinion it is worth learning about if you really want to be guaranteed a good sound everywhere you perform. Using a Feedback Destroyer Another option may be to invest in a hardware device called a "Feedback Destroyer" which pretty much does what its name suggests. I had one of these in my live music gigging rack a few years back and it does a great job. The only reason I stopped using it was because I prefer to find the feedback frequency myself and fix it rather than letting the machine do it for me - I just felt I had more control over my sound that way.

But for anyone who doesn't know how to find feedback frequencies, set Q factors, and cut them by the right amount of dB's etc, a Feedback Destroyer machine will do most of all that work for you and could be an easy-to-use alternative to doing it all manually. For more information on Feedback Destroyers, click here and type feedback destroyer in to the product search... Article Written by Kenny Campbell (This article cannot be reproduced without express permission) © (all rights reserved) How to Eliminate Audio Feedback Home : Audio : Feedback How to Eliminate Feedback Audio feedback is the ringing noise (often described as squealing, screeching, etc) sometimes present in sound systems. It is caused by a "looped signal", that is, a signal which travels in a continuous loop. In technical terms, feedback occurs when the gain in the signal loop reaches "unity" (0dB gain). One of the most common feedback situations is shown in the diagram below - a microphone feeds a signal into a sound system, which then amplifies and outputs the signal from a speaker, which is picked up again by the microphone. Of course, there are many situations which result in feedback. For example, the microphone could be replaced by the pickups of an electric guitar.

(In fact many guitarists employ controlled feedback to artistic advantage. This is what's happening when you see a guitarist hold his/her guitar up close to a speaker.) To eliminate feedback, you must interrupt the feedback loop. Here are a few suggestions for controlling feedback: Change the position of the microphone and/or speaker so that the speaker output isn't feeding directly into the mic. Keep speakers further forward (i.e. closer to the audience) than microphones. Use a more directional microphone. Speak (or sing) close to the microphone. Turn the microphone off when not in use. Equalise the signal, lowering the frequencies which are causing the feedback. Use a noise gate (automatically shuts off a signal when it gets below a certain threshold) or filter. Lower the speaker output, so the mic doesn't pick it up. Avoid aiming speakers directly at reflective surfaces such as walls. Use direct injection feeds instead of microphones for musical instruments. Use headset or in-ear monitors instead of speaker monitors. You could also try a digital feedback eliminator. There are various models available with varying levels of effectiveness. The better ones are reported to produce reasonable results. Other Notes: Feedback can occur at any frequency.

The frequencies which cause most trouble will depend on the situation but factors include the room's resonant frequencies, frequency response of microphones, characteristics of musical instruments (e.g. resonant frequencies of an acoustic guitar), etc. Feedback can be "almost there", or intermittent. For example, you might turn down the level of a microphone to stop the continuous feedback, but when someone talks into it you might still notice a faint ringing or unpleasant tone to the voice. In this case, the feedback is still a problem and further action must be taken. How to Control Feedback in a Sound System | Shure Blog How to Control Feedback in a Sound System Written by Davida Rochman on January 25, 2013 under Education By Shure Notes Editors. Contributors: John Chevalier, Bill Gibson, Frank Gilbert, June Millington, Dan Murphy “John had a semi-acoustic Gibson guitar. It had a pickup on it so it could be amplified. We were just about to walk away and listen to a take when John leaned his guitar against the amp. He really should have turned the electric off.

It was only on a tiny bit and John just leaned it against the amp when it went ‘Nnnnnwahhhh!’ And we went, ‘What’s that? Voodoo?’. ‘No, it’s feedback.’ ‘Wow, it’s a great sound!’ George Martin was there so we said, ‘Can we have that on the record?’ It was a found object, an accident caused by leaning the guitar against the amp.” – Paul McCartney (Source: Many Years From Now, Barry Mile) It’s pretty much common knowledge among students of pop music that The Beatles’ 1964 recording of “I Feel Fine” was one of the first known examples of feedback as a recording effect, even though The Kinks and The Who reportedly (and intentionally) used it in live performances. For most musicians and engineers, though, audio feedback is something to avoid. In this post, we’ll cover some of the fundamentals – what causes feedback and how to avoid it – along with tips from some of our favorite audio pros. What is acoustic feedback? Acoustic feedback occurs when the amplified sound from any loudspeaker re-enters the sound system through any open microphone and is amplified again and again and again.

We’ve all heard it – it’s that sustained, ringing tone, varying from a low rumble to a piercing screech. What causes it The simplest PA system consists of a microphone, an amplifier and one or more speakers. Whenever you have those three components, you have the potential for feedback. Feedback happens when the sound from the speakers makes it back into the microphone and is re-amplified and sent through the speakers again, like this: Here’s an example: Let’s say that that you place the microphone in front of the speaker as shown here. If you tap the microphone, the sound of the tap goes through the amplifier, comes out the speaker and re-enters the mic. This feedback loop happens so quickly that it creates its own frequency, and that produces the howling sound — an oscillation triggered by sound entering the microphone. Placing the microphone too close to the loudspeaker, too far from the sound source, or simply turning the microphone up too high all raise the likelihood of feedback problems. Pro Tip #1 “The worst is vocalists who cup the mic capsule (e.g. rappers who put their hand around the grill of the mic because they think it looks cool).

This invariably makes the mic sound horrible and very susceptible to feedback. More importantly, it changes the directional nature of the microphone, changing it to essentially an omnidirectional microphone. One trick is to cut everything from 800 Hz to 2 kHz, compress it, and hopefully the horrible howling sound will go away and the vocals will still be intelligible. But don’t forget, the best thing to do to control feedback is turn everything down.” – Frank Gilbert, FOH Engineer Park West, The Vic Theater, and The Mayne Stage – all in Chicago Suggestions on how to interrupt the feedback loop Move the microphone closer to the desired sound source. Use a directional microphone to increase the amount of gain before feedback. Reduce the number of open microphones – turn off microphones that are not in use. Don’t boost tone controls indiscriminately. Try to keep microphones and loudspeakers as far away from each other as possible. Lower the speaker output. Move the loudspeaker farther away from the microphone. Each time this distance is doubled, the sound system output can be increased by 6dB. Move the loudspeaker closer to the listener. Each time this distance is halved, the sound system output will increase by 6dB.

Use in-ear monitoring systems in place of floor monitors. Acoustically treat the room (if possible) to eliminate hard, reflective surfaces like glass, marble and wood. Pro Tip #2 “In a well-designed system, the irritating high-pitched brand of feedback isn’t much of a problem unless someone points a mic into a monitor. So long as the performers are careful to always keep their mics pointed away from the monitors, or specifically to point that tail end of the mic at the monitor at all times, that shouldn’t be an issue.” – Bill Gibson , author of over 30 books, producer, performer and Berklee School of Music faculty member When these solutions have been exhausted, the next step is to look toward equalizers and automatic feedback reducers. Ringing Out A common technique used by sound engineers is “ringing out” a sound system by using a graphic equalizer to reduce the level of the frequencies that feedback: Slowly bring up the system level until you begin to hear feedback. Now go to the equalizer and pull down the offending frequency roughly 3dB. If the feedback is a “hoot” or “howl”, try cutting in the 250 to 500 Hz range.

A “singing” tone may be around 1 kHz. “Whistles” and “screeches” tend to be above 2 kHz. Very rarely does feedback occur below 80 Hz or above 8 kHz. It takes practice to develop an ear for equalizing a sound system, so be patient. After locating the first feedback frequency, begin turning up the system again until the next frequency begins ringing. Repeat the above steps until the desired level is reached, but do not over-equalize. Keep in mind the equalizers can only provide a maximum level increase of 3 to 9 dB. Pro Tip #3 “The last time I experienced feedback was in a small venue where I was onstage. As a musician and an audio tech, I’m a sound guy’s worst nightmare. During rehearsal, my headset mic was feeding back and the audio tech kept turning my volume down and telling me that I couldn’t move around. I knew the problem was midrange feedback, so I explained to him that if he just lowered the midrange on the EQ, the problem would go away.

He ‘passionately and firmly’ explained to me that the only way to get rid of feedback was for him to lower the volume and for me to stand still. After enduring the first song, I walked back to the board, reached over his shoulder and dropped the midrange. I sang a couple notes, looked at him, smiled and walked back onstage. (Did I mention I was wireless, too?) The problem was solved and we didn’t talk after the set, but I know he learned something that night.” – John Chevalier , pro audio/video expert, writer and speaker at InfoComm, NAB and other industry events Pro Tip #4 “If there’s one thing I’ve learned in all my years of playing, it’s that the sound engineer has to be extraordinarily vigilant even about protecting the performers’ hearing. My last bad feedback incident was caused by gain stage being manipulated by the engineer without telling us – after we’d gotten to a good place. The resulting, shrieking feedback changed everything – there was nothing but pain filling up space between our ears. Many people forget that EQ’ing something can cause a volume change – right in that frequency. Of course, EQ can remedy volume problems quite easily.

Just take a moment to ferret out the offending frequency or cluster of frequencies – band members protecting their ears, of course – and “forensically” attenuate, which will immediately solve the problem. A hall of mirrors, isn’t it?” – June Millington, FANNY frontwoman, musician and songwriter, co-founder of IMA Automatic feedback reducers are very helpful in wireless microphone applications. Remember that microphone placement is crucial to eliminating feedback, and the temptation to wander away from the ideal microphone position when using a wireless is great. If the performer gets too close to a loudspeaker, feedback will result; a good feedback reducer will be able to catch and eliminate the feedback faster than a sound engineer. Pro Tip #5 “The best ‘gear’ a sound person has is his or her ears. Learn to identify the ringing frequency by doing blind ‘what is that frequency?’ tests using a sine wave generator or test tone generator. Have someone dial up a tone and see if you can identify what frequency it is.

This is great training to identify the problem frequency during feedback howl and how I learned how to tame feedback.” – Dan Murphy, Sound Tech Director, Lakeside Church NOTE: Don’t rely on an equalizer/feedback reducer alone to provide sufficient additional output in a sound system where the microphones and loudspeakers are too close together. You probably won’t get the results you need. For more information, read our post EQ IQ: A Quick Primer .  GET SHURE BLOG UPDATES & MORE VIA EMAIL Subscribe here Audio troubleshooting steps – Ustream Support There are several places in the Producer interface where you can control your audio. Please refer to this guide for instructions on how to confirm audio sources and match to video sources in Prodcuer. Audio too quiet General tips if your audio volume is too quiet Make sure you are using a microphone as close to your sound source as possible. Most microphones only can pick up sound within a few inches. A microphone that is 20 feet away from the person speaking will not pick them up very well and your levels will be too quiet. Make sure you aren't accidentally using the built-in mic on your computer when you mean to be using an external mic.

Follow the instructions for the Ustream Web Broadcaster and Ustream Producer above, or check the audio settings in the encoding software you are using. Check your gain (gain is also sometimes called "level") on your microphone, your audio mixer, your camera and your encoding software. Make sure your levels are adequately turned up on every step of the way. Audio too Loud You'll know your levels are too loud if you hear distortion on your audio signal. Distortion will sound like an unpleasant degradation of the sound, particularly when somone is speaking loudly or when there are loud music sections. Check mic / line input sensitivity and camera input gain One of the most common causes of distortion in your audio signal is when you feed a mic level input a line level signal. If you are routing the signal from an audio mixer through your camera, make sure you set the camera to accept a line level signal and not a mic level signal. Additionally, most cameras have a gain control for the incoming audio. This might either be physical dials / switches on the body of the camera, or a setting inside a menu in the digital display. Locate these settings and adjust accordingly.

Check gain staging on every device in your audio signal path Check your gain (gain is also sometimes called "level") on your microphone, your audio mixer, your camera and your encoding software. Each piece of gear you are using should have a meter. If the level is too loud, it will clip, or hit red on the meter. If your meters look like this, this is very bad and you should turn your volume down. Make sure your meters don't look like this! Audio echo or double Echo or feedback while broadcasting If you are using your built in mic or your microphone or camera is located close to a computer you are also monitoring / listening to the broadcast on, you might experience audio feedback. Audio feedback starts out like an echo, but can also sound like a "robot voice" a repeat, or can turn into a horrible loud screeching noise. Its very easy to prevent audio feedback by using headphones to listen to the broadcast and make sure your headphones are not turned up too loud. There is secondary audio or an echo coming from my computer while I'm watching a Ustream broadcast. How can I turn it off?

If you are viewing a Ustream broadcast and hear secondary audio, you may be hearing audio from another source on your computer, for example you have the same Ustream broadcast playing on Facebook and also watching it on the Ustream channel page. Or you are watching another video on the web and that is playing at the same time as the Ustream video. Make sure that all other open internet browser windows and tabs on your computer are closed or muted prior to viewing your desired Ustream broadcast. Buzz, hum or other artifacts in the audio There is a buzz or hum in the audio signal Buzzes and hums are generally analog audio problems, which means they are not caused by anything in your encoder or anything on the Ustream platform. Two common causes of buzzes and hums are grounding issues or radio frequency interference (RFI). When RFI is really bad, sometimes you are hearing radio stations or people talking through your audio wires. These problems can be difficult to solve since sometimes they are caused by the electrical wiring of the building you are in. Here are some potential solutions to fix a buzz or hum in your audio.

Try switching your cables If you are experiencing a hum or a buzz it is worth it to try to switch which kinds of cables you are using to see if you can reduce the hum or noise you are hearing. Buzzes and hums can be caused by a faulty cable with loose connections, or by using the wrong type of cables. XLR Balanced Audio Cables XLR or Mic cables are generally balanced cables because they have three connections in them: positive, negative and ground. These types of connections are used in most professional productions and are more resistant to hum and other noises. RCA Cables RCA cables are unbalanced connections and are more likely to introduce hum or noise, particularly if they travel a longer distance. RCA connections are usually used on the cheapest consumer-grade gear. 1/4 inch Cables 1/4 inch cables can be either balanced or unbalanced. If you see one line on the end of the cable it means it is unbalanced, two lines means it is balanced. Balanced 1/4 inch cables have three connections, similar to an XLR cable: positive, negative and ground. If you are experiencing hums or buzzes, trying swapping around cables and consider investing in gear that uses balanced and not unbalanced connections.

Adjust your lighting Sometimes lighting circuits can introduce hums or buzzes into your audio. Try plugging your lights into a separate circuit, or turn off any overhead flourescent lights that are not essential to your video production. Try a hum eliminator Hum eliminators are boxes that you plug into your audio signal path which can sometimes kill a hum or buzz. Shop for hum eliminators at B&H. Other audio artifacts: clicks, "glitches", strange noises A clicking sound or glitchy sounds or other inexplicable noises are typically caused by something wrong in the digital signal path. Check for sample rate mismatches If you notice clicking sounds or have no audio at all, check your audio sample rate settings in your encoding software. If you have two digital audio components, the sample rate between the two must match. The most common sample rates are 44.1k and 48k. Typical video workflows have a 48k sample rate. Make sure you set the sample rates so they match. Use high quality AAC audio encoding at at least 96Kbps The other potential cause is a poor quality audio encoding, or too low of a bitrate on your audio encoding.

We recommend AAC audio encoding at 96-160kbps. Audio and video out of sync Most audio / video sync problems are caused by your audio and your video travelling down two different paths and having a difference in the processing time between the two. Embed your audio into your video signal One way to fix audio sync issues is to route your audio through your camera's audio input so that it gets embedded into the video signal and processed the same way in the encoder, rather than going into a separate interface. Use an audio sync delay Another way to fix audio sync issues is to utilize an audio sync delay. Audio sync delays usually allow you to set in milliseconds the amount of delay you want to add to the audio signal. You watch someone speaking while adjusting the control and stop when it looks like the audio and video are in sync. Ustream Producer Pro has a built in audio sync delay for this purpose. You can also utilize a hardware audio delay unit.

Here is an example of a hardware audio delay unit at B&H: Datavideo AD-100 Audio Delay Box Restart the encoder or viewer application It is much less common, but occasionally there can be audio video sync issues caused by the video encoder, in the stream itself, or audio and video can get out of sync for a single viewer. The most common way to resolve these issues is to restart the encoder or restart the viewing application. Related articles Guide to Coping with Feedback Guide to Coping with Feedback 10142 Guide to Coping with Feedback Monday, March 3rd, 2008 Feedback: An introduction to that annoying, head-ache inducing, screeching sound produced by your hearing aid. With tips to solve the problem This is one reason so many people are reluctant to go for a hearing test, accept the results and get fitted for a hearing aid that will deliver the sound of a butterflys wings across the yard. (That is, if you want your device to be that sensitive). Feedback. We all grew up on it from Jefferson Airplane to Green Day.

Feedback is a musical art form when in the hands of a skilled musician, 3,000 amps of raw power and the guts to stand in front of a tower of six-foot speakers and set your guitar on fire. You just dont get that kind of sound from anywhere. But you just might get that loud whistling feedback from your hearing aid and while it may be reminiscent of Purple Haze, its hurting your ears (even more than Woodstock, 69). Todays advanced digital hearing devices typically come equipped with automatic feedback suppression, so when it does occur it may be a sign there is a problem with the hearing device or the device needs a little tweaking to get rid of the shrieking. So, hearing aid wearers and those about to join the ranks (yes, thats you Boomer Boy or Girl), heres an introduction to hearing aid feedback and what you can do about it. Oh, and if you dont think this applies to you because your only 32 years old, how loud did you play your Nirvana CDs? Hearing loss isnt something for oldies, younger and younger people are strapping on the ear gear to get more from life on the hearing side. So read on.

If you dont wear a hearing aid todaytick, tick, tickits only a matter of time. Types of Feedback Youd think that feedback is feedback but no. Is anything ever that simple? In fact, there are three types of feedback, and no, you dont need to know this for the test. The first type of feedback is called acoustical feedback. This is caused when amplified sound produced by the hearing aid speaker is picked up again by the aids microphone creating a sound loop that just gets louder and screechier. If you have ever been talking in a microphone and stand too close to the speaker, you have surely heard acoustical feedback. The same can happen with hearing aids. Most unpleasant and not too cool when youre trying to conduct a business meeting in a quiet room and all attendees hear is the whistling tea kettle emanating from your inner ear. Second type of feedback: mechanical feedback. Pretty hard to live with but easy to fix. Mechanical feedback occurs when physical vibrations are created due to contact between the hearing aid speaker and the hearing aid casing. These vibrations are then transferred through the casing back to the microphone. Finally, the third type of feedback is called electronic feedback.

This feedback is caused by a malfunction in the devices complex circuitry, requiring the services of a hearing aid tech to fix. Five Things NOT to Do When Your Hearing Aid Blasts Feedback Dont tap the device on a table top to see if it stops the noises. These are rugged but sensitive devices and the chances of fixing a feedback problem by knocking on wood are about zero. In fact, you may do additional damage, so no tapping. Unless you fix hearing aids for a living, dont open the casing to see if you can fix it. Chances are you dont know an anode from a diode so what are the chances of finding the one piece of minute equipment causing the feedback problem. Dont let your brother-in-law have a look at it. Just because someone is mechanically inclined doesnt mean they can diagnose and fix a feedback problem. Especially when its your brother-in-law. Dont run the device through the washing machine even on gentle cycle. Sure, hearing aids today are water resistant but come on! Finally, dont drive over the device in your car out of frustration. You just need a minor adjustment or rather your hearing aid does. The fact is, you can only lessen one kind of feedback at home.

Remember Types of Feedback A reminder: acoustical, mechanical and electronic feedback those are the three types. Now, if the problem is mechanical the mic is transmitting vibrations through the casing of the device you need visit your hearing health care professional And if the problem is electronical, that means the case has to be opened and all of the digital bits checked again, not something you should try at home even if digital circuits is your middle name. So, that leaves acoustical feedback the kind produced when the sound from the speaker is picked up by the hearing aid mic and recycled over and over, louder and louder. Now this you may be able to fix. Fixing Acoustical Feedback Here are some common causes of acoustical feedback and a few things to try before running off to the Ye Olde Hearing Aid Shoppe. Check for ear wax. So, okay, its nobodys favorite job but earwax build-up is a common cause of acoustical feedback. When a sound wave hits a solid block of earwax, that sound wave shatters, sending sound every which-away including back out the ear to get re-amplified by the hearing aid microphone.

If ear wax is a problem, use a wax softener and flush the loose ear wax from the ear canal. If this doesnt solve the problem, do NOT start digging away with a hair pin or cotton swab . Youre almost certain to do more damage and more serious damage. Instead, visit a hearing health care professional to have that nasty earwax excised. That should help with the feedback problem. Check the fit. A loose fitting hearing aid allows amplified sound waves to escape the ear canal around the hearing aid, reach the mic and off we go again in a feedback loop. And check this out if youve been dieting and youve lost 10 or 20 pounds (good for you) that weight loss can affect the fitting of your hearing aid. To test the fit of your hearing device, try these steps: Press the hearing aid further into your ear canal. If the feedback stops, a loose fit is most likely your problem. Place a small dab of Vaseline on the part of the device that fits into the ear canal. This liquid sometimes seals cracks, indicating a loose fit and the need for a refitting. Be careful not to get it inside the hearing aid.

Try placing soft hearing aid wraps around the canal portion of the hearing aid. These are sponge-like wraps specifically made for hearing aids that adhere to the canal portion of the hearing aid, creating a tighter fit. Try putting a coating of clear nail polish on the part of the hearing aid that fits in the ear canal. Let it dry! This might just add enough circumference to create a tighter seal. It is important to note these are all temporary remedies for a loose fitting hearing aid. You may need to visit your hearing health care professional to have your hearing aid re-cased or have a new ear mold made to prevent further feedback. But hey, if you just lost 20 pounds, thats a good problem to have. Speaker Placement With custom in-the-ear hearing aid devices the feedback problem may possibly be caused by an ill-fitting hearing device. When the hearing aid is built by the manufacturer, the hearing aid technician places the receiver (speaker) of the hearing aid so that will direct down the ear canal. If the direction of the receiver is off and pointing directly into the wall of the ear canal, it can cause the amplified sound to bounce back into the hearing aid and the whistling begins.

This is more likely to occur for someone with a sharp bend in their ear canal. To test if this is the cause, simply try pulling your ear lobe back. By pulling your ear lobe back you essentially open up your ear canal. If the feedback stops, this may be your problem. With the advances in digital shell design by hearing aid manufacturers, this is a rare cause of feedback but should still be considered. Talk to your hearing health care professional if you suspect this as a possibility. Hearing Aid damage This is a common problem for in-the-ear devices that rest within the ear canal that are subjected to more cleaning due to wax. The sound tube may become damaged over time by aggressive cleaning, the mic may have gotten pushed in, or there could be a crack in the hearing aid casing. In the case of a behind-the-ear device, the tubing tends to harden over time and once more susceptible to cracking. Any of these scenarios could potentially cause the amplified sound to leak and become re-amplified, causing once again feedback. Warning Feedback can be caused by a number of factors some under your control, others not so much. And visiting your hearing health care professional may not solve your problem the first go-round.

Typically, feedback comes from amplification in the higher frequency ranges so some persons may be more susceptible to feedback depending upon their hearing loss and the type of hearing aid they wear. Feedback issues do often require a trip back to your hearing professionals office but it will be well worth it to determine the cause of the feedback. Feedback Suppression Most advanced digital hearing devices come with the automated convenience of feedback suppression. When the device detects a hint of feedback, it automatically adjusts itself to suppress the feedback. Costing slight more than the bare-bones, entry-level hearing aids, these automated feedback suppression systems may well be worth a little extra on the front end for years of listening comfort on the back end. That extra money will soon be forgotten. The feedback-free results will make you smile everyday for years to come. How to reduce the feedback loop between the microphone and speakers in Windows 7 How to reduce the feedback loop between the microphone and speakers in Windows 7 Select Product Version Summary You may hear feedback from your PC speakers when one or more of the the following conditions are true: You increase the Microphone Boost option. The speakers are too close to the microphone. The speaker volume is turned up so as the microphone hears the speakers. You have a very sensitive microphone.

More Information You may be able to reduce or eliminate the feedback you are hearing by trying the following steps in Windows 7: Open Control Panel. Open the Hardware and Sound setting. Open the Sound setting. Select the Recording tab and double-click your microphone you have selected as the default recording device. Click on the Level tab and reduce the Microphone Boost setting. Note: This setting may not be available for some microphones. You may also be able to reduce the feedback loop by selecting the Enhancement tab in the microphone's properties page and enabling one of the following options: Enable Noise Suppression Enable Acoustic Echo Cancellation Note: These settings are audio hardware and software specific and may not be available for all microphones. Properties Microphone - Android Apps on Google Play Microphone ( 18,736) Description This very simple app just sends audio from the mic to the speaker, plug it into your computer or whatever using a 3.5mm male to male headphone jack and you get a free mic. It isn't possible to make a lag free mic on Android yet, but it's good enough for emergency use.

Read more 1 5,053 Matthew Kuraja Good spy tool I've been looking for an inconspicuous, Bluetooth enabled, streaming audio device with a long battery that I can leave in a room and listen nearby on Bluetooth enabled headphones. Surprisingly not an easy product to find online. But this free app let's me use my smartphone to eavesdrop. I gave it 4 stars instead of 5 because the notification icon doesn't go away even if you do select it to turn off the app. Selecting it again doesn't turn it back on. Just a dead notification icon that doesn't go away. Steven Wang simple and perfect. Minimal delay (Android issue!), but can actually have a quiet conversation (using wired headphone). Watching shows with low volume, lectures, etc. A directional mic might work for having conversation... or just quickly "off" the amp when talking. Also a great way to baseline the performance of the mic on the device. I use other apps if needing sound processing/cancelling.

Turns out my nexus 5 does great with just this app and no fancy processing (that usually makes background noise very "screechy") Leighton Bloch Exactly what you are looking for A free mic for the computer and works great as long as you have a 3.5 male to male audio jack. What more could you ask for? It is very Light weight and delivers crisp clear audio and I can use it for hours at a time without battery trouble. It will make loud noises if you activate the app without the audio jack inserted. Douglas Silva Simple and Efficient. The app do it's work quite efficient. It weighs nothing in internal memory size and it's extremely simple to work. Of course you'll must pay attention to the instructions to make it work and the microfone does not make a real-time response. But it makes your job! RECOMENDED FOR THOSE WITHOUT A PROPER MICROFONE Kevin Henson Good Until It's Not Works good most of the time. Then one day you'll use it and your mic is very low and people say you sound like you're in a toilet bowl. Edit: It quit working altogether so I'm gonna have to find something else.

Charles Butcher Works well with Nexus 4 Simple and works well with my Nexus 4 running Android 4.4.4. You can use it as a Bluetooth mic, and I was surprised to find that the mic output is mixed with other audio from the phone, so you can play music and speak over the top. As the dev says, probably too laggy for karaoke though! User reviews Matthew Kuraja June 2, 2015 Good spy tool I've been looking for an inconspicuous, Bluetooth enabled, streaming audio device with a long battery that I can leave in a room and listen nearby on Bluetooth enabled headphones. Surprisingly not an easy product to find online. But this free app let's me use my smartphone to eavesdrop. I gave it 4 stars instead of 5 because the notification icon doesn't go away even if you do select it to turn off the app. Selecting it again doesn't turn it back on. Just a dead notification icon that doesn't go away. Full Review Steven Wang January 17, 2016 simple and perfect. Minimal delay (Android issue!), but can actually have a quiet conversation (using wired headphone). Watching shows with low volume, lectures, etc.

A directional mic might work for having conversation... or just quickly "off" the amp when talking. Also a great way to baseline the performance of the mic on the device. I use other apps if needing sound processing/cancelling. Turns out my nexus 5 does great with just this app and no fancy processing (that usually makes background noise very "screechy") Full Review Leighton Bloch June 26, 2013 Exactly what you are looking for A free mic for the computer and works great as long as you have a 3.5 male to male audio jack. What more could you ask for? It is very Light weight and delivers crisp clear audio and I can use it for hours at a time without battery trouble. It will make loud noises if you activate the app without the audio jack inserted. Full Review Douglas Silva May 25, 2014 Simple and Efficient. The app do it's work quite efficient. It weighs nothing in internal memory size and it's extremely simple to work. Of course you'll must pay attention to the instructions to make it work and the microfone does not make a real-time response. But it makes your job!

RECOMENDED FOR THOSE WITHOUT A PROPER MICROFONE Full Review Kevin Henson June 4, 2016 Good Until It's Not Works good most of the time. Then one day you'll use it and your mic is very low and people say you sound like you're in a toilet bowl. Edit: It quit working altogether so I'm gonna have to find something else. Full Review Charles Butcher August 5, 2014 Works well with Nexus 4 Simple and works well with my Nexus 4 running Android 4.4.4. You can use it as a Bluetooth mic, and I was surprised to find that the mic output is mixed with other audio from the phone, so you can play music and speak over the top. As the dev says, probably too laggy for karaoke though! Full Review Jeff Martens July 29, 2014 Works w/o extra permissions Works as advertised and doesn't require the invasive permissions of the alternatives. Not 5 stars, though, since it hangs around in the background with an icon in the upper left until killed. Pretty amazing all the low ratings from morons ignorant of feedback.

Full Review Debagnika Paul September 2, 2015 Its great but... Everything's fine, even the sound quality but the only problem is that whenever i'm speaking something, the speech output comes in a delayed manner... Thats a drawback in this app. The one who invented this, please take care of this issue... Full Review A Google User June 13, 2012 Droid x If people would use their heads a little ratings would be higher. This isn't made to blow through your phone speaker. I use it on a Bose bluetooth/wireless speaker, the thing kicks as when used properly. Think people, if you're using your phone speaker to talk to someone close you probably dont need a microphone Full Review Jeff Keyeux June 28, 2015 Sounds Good! My new Photive bluetooth earbuds fit snuggly and muffle out environmental noise. In a gym or at home this would be fine but when I am biking on roadways, I need to be aware of cars and people around me. This app works simultaneously with Google Play to allow me to do just that. Yes, there is a delay but I am happy to have it until improvements are made!

Full Review A Google User January 27, 2012 Good concept I have a huawei m865 which really is a pretty sucky phone however your program offers nothing going out of the 3.5 mm jack so though it may work on other models it doesn't work on mine. But good concept just needs some work. Full Review A Google User August 16, 2012 Does what it says Simple easy setup. Friends + family heard me perfectly on my PC. Slight delay when I tested, but developer warned about that so no stars off. Great app thank you! Full Review Lorne Serpa September 29, 2013 Fun Got this only to bond to devices in stores, walk away and talk when people pass the blue tooth device I paird to. Ya, nothing but causing trouble, fun none the less. Thanks. App is too loud and also significant lag. Full Review Vitorio Maric January 8, 2015 Works like it should This app listens to your mic on the phone and plays the mic input on the phones loud speaker into almost real time.

Plugging the phone into the microphone port on the pc via a 3.5mm cable diverts the audio to the pc. I successfully used this app to communicate over Teamspeak, Skype etc. Some issue though, I find I have to plug the aux cable into the phone ONLY first, start recording and then plug the cable into the computer otherwise the audio is not diverted to the pc and the loudspeaker stays on. Also when the device goes into sleep (due to no interactions), the app stops working after a short while, no more mic. Then I have to repeat the whole process again to get it back up, minor annoyance. Full Review Jason Garcia October 9, 2015 Amazing But give a warning to pressing the mic without headphones WHAT WOULD BE really cool about this app in the "future" like you ampilfy your microphones or boost it and take off the noise in the background. Or call it noise cancelation hands down on this app really great but love it if you but these features on. THANKS 😊 Full Review Ed Kolis October 17, 2016 Claims to damage your phone It expressly claims in the instructions that it causes feedback that will destroy your speaker.

I don't know why I didn't uninstall it right away, but I will now, in case someone borrows my phone and opens it up. Full Review Bradley West March 22, 2014 Doesn't work I have a desktop computer, so I'm pretty sure that might be the problem but I plugged in my male to male cable and got everything situated. I plugged it into the input outlet and then tryed the input. Both didn't work. So I tryed using a splitter cable and that didnt work. I tryed plugging it into the speakers and that didn't work. I admire the effort but it doesn't work. Full Review Eric Smerkonich September 19, 2014 Great for conference calls Just used this on a really boring conference call. I don't have a phone headset on my work phone so I downloaded this app and set the desk phone speaker on my S4 mic and plugged the headphones in. Was able to keep working and be productive this way. I was tired of holding the desk phone to my ear and this saved the day!

Full Review lucky lucky May 5, 2013 Great app Such a good app, that one happy user is hiding behind trees scaring ppl thru his car bluetooth as they walk by it. He calls ppl "stupid" this app is so good makes dumb ppl dumber. Lol. Full Review Suman Bhowmik December 30, 2013 Sony bluetooth speakers paired with my phone Worked well for me. Sony bluetooth speakers paired with my phone and we had a working wireless mic. Just one problem though. The sound echoes at times. Five stars if that can be fixed Full Review A Google User February 1, 2011 Mic cuts out when screen is shut off, and sometimes even if left untouched for too long. Also, no in-app volume controls. Still useful, but average. Full Review Eric Johnson April 30, 2015 Plug the cable into your phone first! This app only works if you plug the 3.5 mm cable into your phone first. Then start the app and click the microphone. Then plug the other end into your computers mic port.

If you don't do it in this order you'll get all sorts of screeching and the app won't correctly route the audio. But it works great if done this way. Full Review A Google User February 3, 2011 Exactly what I was looking for but could use some more options. Also internal speakers should be disabled. They're useless and only give feedback. Full Review Conway Bown June 25, 2015 Feedback is terrible Because of the lag, the feedback into the mic causes a loop that makes it unworkable. Too bad. It had promise. Full Review Rick Ruehl January 23, 2013 Great App I needed to do some dubbing of videos and tried several microphones and decided after hisses and noticable flaws in cheap headsets to use my smartphone. The logic is that these things are designed for great voice. I plugged the phone into the mic in, pressed the icon and it works better than any other microphone I had. Since I am recording tracks and editing them onto the video I notice no delay or anything. Great App. Full Review A Google User January 20, 2012 Wait A Sec... As mentioned, there is delay.

It's just a second so that's close enough for an impromptu speech. This mic doesn't feedback as much as Mic To Speaker. Full Review RmaN August 31, 2014 Exactly what I wanted for recording my audio to DAWs Exactly what I wanted for recording my voice into DAWs & feedbacks while not connecting the aux cable are an interesting phenomenon :-P but it's missing the gain and preamp feature! That's necessary Full Review Jason Riha July 9, 2016 The about pop up when you first download is just awesome and truthful Descent unless you get an echo by standing too close to the speakers.. then your speakers pop.. which can be awesome but usually isn't.. killer app Full Review A Google User August 12, 2011 x10mini + bluetooth speaker -> wireless mic Great! I've tested with my bluetooth speaker. Now I've a wireless microphone for free. Quality is good, there is a bit of delay and you need to be careful with the echo. Full Review David Yokelson February 3, 2014 Works great! Clean, clear sound.

The only issue is a slight lag, which is a limitation of the Android architecture. I like the super-simple interface...just an on-off switch. Full Review Ismail Tofie June 13, 2016 Almost real time and echo issues. But better than what I had before. I want to use it so I don't shout in my van at kids but merely speak through this device. Also I love that it doesn't pause when the phone's screen time out. Full Review Richard Parks December 14, 2014 This is great to broadcast to Bluetooth speakers! There is enough delay to prevent feedback with normal volume levels. Looking forward to mic gain a d any other upgrades. Full Review Harjeet Jeet November 29, 2015 Eco problem Its connecting fine with Bluetooth speakers , but to much eco... pl provide the solve the same.. or provide the steps to .. resolve this problem Full Review quagmirecat September 4, 2016 Strange sound A really loud sound starts to play whenever I use the app, and the mic is turned on.

Used to work up until today, will give five stars when fixed Full Review A Google User April 6, 2011 The screechy noise is feedback, people, read the description. I use it to record to OneNote, much better than laptop mics. Slightly buggy but works. Full Review Michael Cartwright March 19, 2016 Latency issues The time between a spoken word and actually hearing it on the phone ( even through headphones) sucks. A true microphone or good microphone app has no latency issues. Full Review A Google User January 2, 2011 This is what I was looking for. Gaz honestly revealed why there is an annoying delay. I have left it installed in anticipation of an OS update. Full Review EZE V January 31, 2014 in moto g decent in moto g, sometimes it pops up googles own microphone search (quite annoying), but when it works its decent, i like that it works even with screen off. MY FATHER IS DEAF AND THIS MIGHT BE USEFUL AS A HEARING AID DEVICE, PLEASE MAKE THE VOLUME LOUDER AND I CHANGE TO 5 STARS.

Full Review A Google User May 31, 2011 Notification doesn't go away after I turn it off. I click it to cancel, kill the service, nothing works. I have to restart phone. Nexus S 2.3.4. Full Review A Google User December 31, 2011 Stupid people... All you other users must not know what a mic app is for. Its not meant for ur phone speaker duh. The speaker is way to close. I use it on my Bluetooth in my car to scare people walking by as I hide behind a tree or something lol Feedback Prevention: A Closer Look at Microphones and Monitors - Behind The Mixer Behind The Mixer Home > Church Audio 101 > Feedback Prevention: A Closer Look at Microphones and Monitors Feedback Prevention: A Closer Look at Microphones and Monitors Topics: microphones , Monitors | Author: Chris Huff | Date: October 11, 2012 It’s all about location, location, location. Photo provided by cricava Monday’s post on feedback prevention prompted a good question from Ryan, a reader. He said, “…there was one phrase that jumped out at me.

Specifically, ‘Regarding floor monitors, vocalists should be very close to their floor monitor.’ I wanted to ask what the reasoning is behind this? I would think the further away the singer is, the more the sound is diffused; ergo, feedback is reduced.” One of the hard parts of live audio production is taking into account all the different factors that are needed and finding the balance in using them all to create the best sound. Monitor usage is a perfect example. A musician needs monitors for hearing sounds to be in key and in time. The sound tech needs the musician to sing into a microphone using the right technique so they can get a solid sound for mixing. The audience / congregation needs to hear a great house sound. Looking specifically at a fictional vocal singer, we have five factors to take into account to make all of this work; The microphone they use. How they use the monitor. What they hear in the monitor. 1. The microphone they use Cardioid (named so because of the heart-shape. Picks up primarily in the frontal section with reduced pickup on the sides.) Microphones come in a variety of types with a variety of frequency responses but you need to focus on their polar pattern for now.

The polar pattern is the area around the microphone head and how a particular microphone picks up sound around it. For example, an omni-directional polar pattern picks up sound all around the microphone. A cardioid (see image) picks up sound in the front and sides but not behind the microphone. Let’s give the vocalist a common, albeit aging, Shure SM58 microphone. This is a dynamic vocal microphone with a cardioid polar pattern. As an aside, you need to find out the polar pattern of your microphones. They will either have a small picture of it on the microphone or you can check out the manuals. Most microphone spec’s are available online so don’t fret if you don’t have the manuals. 2. How they use the microphone Vocal microphones need to be held right up to a singer’s month, tilted at about a 45’ish degree angle up to their mouth. This way, you can get the clearest sound without getting other stage noises in the mix. While you can’t get total sound isolation in the live environment, by having the sound source so close to the microphone, you can get pretty darn close. Let’s say our vocalist is properly holding the microphone. 3.

The monitor they use Focusing on the source of this question and the original topic of feedback, two monitor types are to be noted; floor monitors, also called floor wedges, and spot monitors. Spot monitors are smaller and are usually placed on a stand. The vocalist, and any musician, sees the monitor as a necessity. If they can’t hear other singers, they can’t harmonize. If they can’t hear the right rhythm instrument, they can’t sing in time. It’s for this reason musicians might spend a lot of time asking for the right monitor volume and mix. Let’s put our vocalist in front of a floor monitor. 4. How they use the monitor Proper monitor placement. Our vocalist needs to be standing on-axis to the floor wedge. The moment they are off-axis, that is to say they are outside of the sound cone radiating from the monitor speaker, then they are hearing significantly less volume. But how close do they need to stand? This leads us into the topic of stage volume. Stage volume is the amount of sound on a stage. Sources of stage volume would be acoustic instruments, singers, drum kits, and monitors. These are all different sounds that can be heard on stage that don’t emanate from the house speakers.

Our vocalist needs to stand as close as possible to their floor wedge because of two reasons; They need to clearly hear their monitor You need to keep the stage volume to a minimum. Stage volume, when excessive, destroys the sound in the room because, at that point, the stage volume is exceeding the house volume. Excessive stage volume also makes monitor mixing a nightmare. 5. What they hear in the monitor Without going into detail on monitor mixes, I’ll hit a few highlights as it would relate to our vocalist. First, they need to hear voices for harmonizing and a rhythm instrument or two for timing. They DON’T need every sound in their mix. Second, they need to hear all of these in the right relationship to each other. Think volume. Only now can the question be answered… “‘Regarding floor monitors, vocalists should be very close to their floor monitor.’ I wanted to ask what the reasoning is behind this?” Bringing this all together and remembering we are scoping this around feedback… Feedback, in the case of monitors, is produced when a sound is looped between the microphone and the monitor to the point where the volume looping between the two begins to significantly increase. So why do we want our vocalist up close to their monitor?

The biggest point that I can make is that when you properly set the gain for that vocalist’s microphone, they keep it up to their lips, and you have ONLY enough volume coming out of the monitor, then feedback won’t be a problem. Where feedback does come into play is usually when; The microphone is too hot and picks up more monitor than necessary. This goes back to setting the proper channel gain. The monitor is too loud and the microphone is looping the sound. Going back to our stage volume discussion, we don’t want to negatively impact the house volume or produce too much volume from one monitor that it affects others on the stage. This all leads back to the original article and the three ways to easily prevent feedback; Place microphones in the right relationships to monitors. Close enough the singer hears the volume they need when they are standing on-axis to the monitor speaker cone. Teach musicians to use the proper vocal microphone technique. The moment a vocalist drops the microphone from their mouth to their chest or their stomach, a significantly greater amount of gain is required which can produce feedback and will pick up more sounds on the stage. And dropping the microphone to their side will certainly throw everything into a loop because of the close proximity from the monitor the microphone.

They need to keep the microphone up to their mouth or step away if they drop it to their side. Use the proper gain setting technique. The channel gain setting is foundational for all your work. It gives you the amount of channel signal you need and is the best aid in preventing feedback. A channel that’s too hot will cause just as many problems as a channel that’s not loud enough. The Take Away You have to keep several areas in check when producing live audio. These areas include stage volume, feedback, and monitor usage. To Ryan’s question, the farther away the vocalist from the monitor, the more monitor volume and thus stage volume. But when you place the vocalist in the right relationship with the monitor and they use proper the microphone technique, then they hear everything they need, you get the right sound signal you need, and the congregation hears the sound coming from the house speakers, not from the stage. *Tip: If you are having problems with feedback when the monitors are set and the musicians are properly using the microphones, check the type of polar pattern of the microphone. You are likely using an omni-directional microphone wherein a cardioid microphone would be better suited for your situation. Looking for all the details behind what makes microphones unique?

Check out this guide to microphones with a focus on vocal microphones. DOWNLOAD THE CHURCH AUDIO 32-POINT SOUNDCHECK CHECKLIST Get the FREE checklist so you don't miss a step! Everything from stage work to mixing to communications. Run a smooth soundcheck with maximum time for mixing. DOWNLOAD NOW

Question: What causes a screeching sound when a live microphone is put too close to a speaker?
Answer: Feedback