Vibration analysis for beginners - Page 1
Forum section: electronics / projects

author: ruairi
author_rank: Frequent Contributor
timestamp: October 09, 2016, 02:53:58 am
content: Hi all,I'm interested in studying vibrations in flooring and wall panels in recording studio spaces and have just started studying the principles involved. In my googling I found this product which looks fantastic for my purposes (making baseline measurements, understanding issues, implementing fixes and verifying).http://www.mide.com/collections/shock-vibration-data-loggersHas anyone used the above? Or know of a comparable open source project or something more affordable for experiments?Cheers,Ruairi

author: singapol
author_rank: Frequent Contributor
timestamp: October 09, 2016, 04:33:16 am
content: I'm not an expert but you could use this thing if you can afford it. To be fair it's high tech and works out of the box with a pc and software. It works to 20Khz. the limit of human hearing.My take is that you want to "manage" sound vibrations or at least control and not eliminate it as you might as well put the recording studio in a anechoic environment and hear what kind of sound you get.In musical instruments when dealing with the harmonic frequencies and reverberations against walls/along floors that also has an effect on the sound but your targeted device only gets you 20khz. If all this is too expensive then get an accelerometer and a 10mhz. usb picoscope with it's software...less complications or is i?.PS. you would do well to learn the properties of hard woods and it's processing. and how sound travels through common materials like concrete and metal.

author: ruairi
author_rank: Frequent Contributor
timestamp: October 09, 2016, 05:04:35 am
content: Thanks Singapol,I left quite a bit out of my post in the interests of keeping things simple. I've been a music pro for a long time and in one of my jobs set up speakers for house hold name music producers and artists.I've got a good grasp on what works in room acoustics and speaker interaction but I defer to the true geniuses that I work with when it comes to room design. I've ended up in a situation where I need to rehab a temporary studio for a well known artist in a less than ideal space, and in a very short time frame. The original acoustician dropped the ball spectacularly.One issue in the room is a wooden floor over a cavity which is vibrating and resonating (the speaker system in the room is about 4,000 Watts), I will have contractors to help me rectify the issue but I'd like to measure it as I go.In this case I want to eliminate the vibrations in the floor and certain freestanding wall panels as much as possible, if it's not on the recording leaving the speakers I do not want to hear it! I'm mostly interested in low frequency stuff, approx 1 to 200 Hz.Absolute levels and calibration are not important, just getting an understanding of trends/frequency shifts as we add mass and bracing.

author: singapol
author_rank: Frequent Contributor
timestamp: October 09, 2016, 04:34:23 pm
content: Quote from: ruairi on October 09, 2016, 05:04:35 amNice to have work that is also your passion.Still don't be led by the nose by your geniuses as you shouldknow what they are up to yourself. Sure it takes effort to learn but it will stay with you longer or a lifetime.Let us know of your progress. Below are some links for acoustic virgins like myself.Room treatment:http://ethanwiner.com/acoustics.htmlhttps://randycoppinger.com/studio-construction/http://www.farrat.com/wp-content/uploads/2015/06/Acoustic-Floating-Floor-Systems.pdfhttp://www.auralex.com/wp-content/uploads/2014/10/acoustics101v3_0.pdfhttps://www.vocalboothtogo.com/soundproofing-5/http://acousticsfreq.com/how-to-build-your-own-acoustic-panels/http://www.controlnoise.com/how-to-soundproof-a-ceiling/Studio design:http://www.ahisee.com/content/rsdpart1.htmlhttp://recordinghacks.com/2008/10/07/touring-electrical-audio/http://www.soundonsound.com/techniques/practical-soundproofing

author: ruairi
author_rank: Frequent Contributor
timestamp: October 09, 2016, 05:04:15 pm
content: Thanks Singapol, I am indeed lucky to work in music.When I say geniuses I mean that I actually do some work with the best studio designer I know of, and master records in a room that he designed. I'm well aware of all of the sources you linked and some of them offer very questionable information. If I started dropping names of projects I have involved with it would be very cheesy but needless to say I've been involved in a lot of studio builds for for artists and studios that you have heard of.My question really is about vibration analysis, in ground up designs this is taken care of and in many short term studios it is ignored completely. This current project is a little unique in that I need to deal with the vibration issues and I'd like to use it as an opportunity to learn as I go.Most people strategies for dealing with vibration are to add mass and dampen, often without an understanding of the problem. I'd like to do a little better.For a little context/fun these are the speakers in the room (850 sqft) -http://pmc-speakers.com/products/professional/active/bb5-xbdThey are about 7 feet tall.

author: singapol
author_rank: Frequent Contributor
timestamp: October 09, 2016, 05:55:27 pm
content: Thanks for the headsup..to give others a sense of scale of the speakers you mentioned:I think not easy to tune?https://crustyloafer.smugmug.com/Electronics/PMC-BB5-XBD-Demo-Weekend/i-Krj5PzC/Have a look at this vibration analyser: more professional /real time vs a data logger?http://ei-calc.com/?gclid=CMji9ZWkzs8CFVAfaAod3tYFMA

author: _Wim_
author_rank: Super Contributor
timestamp: October 09, 2016, 06:48:39 pm
content: Don't know what kind of system you use to measure speakers (I assume mic + soundcard + pc), but if I were you, I would buy an accelerometer with a preamp that I can connect to my pc, and then use the same spectral software used for testing the speaker system. You can sweep the speakers and monitor for resonances the same way you would do with a microphone to test the speakers.If you have a little bit of time, accelerometers from MMF (http://www.new.mmf.de/standard_accelerometers.htm) regularly pop-up on Ebay for very affordable prices (especially on Ebay Germany). The accelerometers themselves go between 50€ and 100€, a matching pre-amp for around 150€ to 250€ (for example Robotron 00031, seehttp://www.messmikrofone.info/schwingungsmesser-00-031/)

author: _Wim_
author_rank: Super Contributor
timestamp: October 09, 2016, 06:57:25 pm
content: Apperently you can get them even cheaper if you are lucky:http://www.ebay.ie/itm/191844885769With 3 accelerometers and a pre-amp, that a nice bargain if you can use it...

author: ruairi
author_rank: Frequent Contributor
timestamp: October 09, 2016, 10:47:24 pm
content: Singapol,Not so difficult to tune, the speakers themselves sound great. They do sound very impressive when set up in a good space.Will look into that EI-Calc, thanks!Wim,Yes, I use a calibrated mic, REW and a Prism Sound Lyra interface for room measurements. It is incredibly powerful for free software.I will look into those accelerometers you mentioned.Cheers,Ruairi