Sending audio signal - Page 1
Forum section: electronics / projects

author: ElectricGuy
author_rank: Regular Contributor
timestamp: July 21, 2014, 06:15:17 pm
content: Hi everyone;In the past, before I moved house, had my PC connected to my HI-FI with a audio cable( PC Line-Out -> Hi-FI Audio In) ( 3.5mm jack to RCA ).Now i have a problem. I have my PC in one bedroom, and the HI-FI system in the Living room. I want to send the audio out of my PC to the Hi-Fi system, however cables is out of the question.Is was thinking in something like this, but i'm afraid getting interferences since i have wi-fi at 2.4Ghz, and also some other components at that frequency, like Xbee, etc.http://www.ebay.com/itm/2-4GHz-FM-Wireless-Audio-Video-AV-Transmitter-Receiver-Kit-CCTV-Camera-VCR-DVD-/200798785410?pt=US_Audio_Video_Transmitters&hash=item2ec08a4f82( I don't know the frequency channels of this equipment )I saw a long time ago powerline equipment with the possibility of sending A/V together with ethernet, however i do not see that anymore.Could you guys give me some more options?Thank you;

author: Prime73
author_rank: Regular Contributor
timestamp: July 21, 2014, 06:28:33 pm
content: I would just use Apple's airplay or similar in Windows world (i'm sure something should be available)

author: pyrohaz
author_rank: Regular Contributor
timestamp: July 21, 2014, 07:24:16 pm
content: An XBee would require a lot of surrounding electronics to transmit and receive data, namely an ADC and MCU on one end (16bit minimum, 24bit if you want "pro" audio), and another MCU with a DAC on the other end. Chances are that you'd get bits of jitter at times, causing your music stream to sometimes glitch. Wifi channels start at 2412MHz up to 2462MHz in steps of 5Mhz. The link you provided on ebay works on a choice of 4 channels, 2411Mhz, 2431Mhz, 2451Mhz and 2471Mhz. With the link you provided having spacings of 20Mhz, this makes me assume that the whole link requires a 40Mhz bandwidth (makes sense if its transmitting video I suppose). Unless your router is operating in the higher channels, you could probably get away with the 2471MHz channel. I couldn't tell you if you'd get interference or not however.

author: Rigby
author_rank: Super Contributor
timestamp: July 21, 2014, 07:34:52 pm
content: Quote from: Prime73 on July 21, 2014, 06:28:33 pm+1.

author: tonyarkles
author_rank: Regular Contributor
timestamp: July 21, 2014, 07:58:28 pm
content: I've heard good things about the Roku, and it's pretty cheap:https://www.roku.com/ca/what-is-roku

author: Circuitous
author_rank: Unknown
timestamp: July 21, 2014, 09:03:27 pm
content: You could try something like this from RocketFish:http://www.amazon.com/Rocketfish-Wireless-Sender-Receiver/dp/B003L1WR3SI haven't used that particular device, but I have a pair of their wireless speakers that I've been using for several years. My transmitter for the speakers sits just a few feet from a wireless router and I've had no interference.

author: ElectricGuy
author_rank: Regular Contributor
timestamp: July 21, 2014, 10:34:08 pm
content: Quote from: pyrohaz on July 21, 2014, 07:24:16 pmHi everyone;@pyrohazI never said it would use xbee to transmit audio.@all;Thank you for your answers... good equipment advised. I will check them all.Any other options?Thank you

author: pyrohaz
author_rank: Regular Contributor
timestamp: July 22, 2014, 08:36:57 am
content: Quote from: ElectricGuy on July 21, 2014, 10:34:08 pmMy apologies! I misread your initial post.

author: wiss
author_rank: Frequent Contributor
timestamp: July 22, 2014, 10:42:37 am
content: 10 Years ago I had a head-less, disk-less, net-booting SparcStation5 with 5V connected fan as (audio) media-player, now I have a Raspberry-pi and DLNA for the same purpose.

author: David Hess
author_rank: Super Contributor
timestamp: July 22, 2014, 04:22:16 pm
content: This is the kind of thing I would use audio over ethernet or IP for but I am unaware of any inexpensive hardware for this. Latency may be a problem in some applications.If you avoid ground loops, then running a physical cable will work well.

author: Rigby
author_rank: Super Contributor
timestamp: July 22, 2014, 05:14:03 pm
content: Quote from: David Hess on July 22, 2014, 04:22:16 pmRaspberry Pi, BeagleBone Black. Full Linux OS, support USB sound cards. netcat is a little known linux utility that will get you streaming audio in no time. it's like the 'cat' tool, except over networks.

author: m3ga
author_rank: Newbie
timestamp: August 30, 2014, 10:00:42 pm
content: Looked at the rocketfish solution and I would need to buy two, since my active speakers are in two different corners of the room only plugging into the power wall sockets in each respective corner...So this sucks...The better idea would be to have a simple IR sender and one IR receiver for each channel.Fully analog and works as robust and low power as a remote control.Would it be possible to modulate the two 20kHz audio channels to a fixed MHz carrier for the IR?Did someone do this already maybe?If not ... using three raspberrys over Wifi with netcat audio streaming would be a valid hack ;-) ...

author: David Hess
author_rank: Super Contributor
timestamp: August 30, 2014, 10:33:14 pm
content: Quote from: m3ga on August 30, 2014, 10:00:42 pmIt is certainly feasible and I have seen it done with wireless headphones. It might be interesting to use existing FM stereo modulation/demodulation but since there is no need for backwards compatibility, there are lots of different ways to go about it including PCM.

author: m3ga
author_rank: Newbie
timestamp: August 31, 2014, 10:09:05 am
content: I could shut up and buy this:http://www.amazon.de/Transmitter-Receiver-CM3-Wireless-Sender-blau/dp/B00DUUG8BM/ref=sr_1_4?ie=UTF8&qid=1409436304&sr=8-4&keywords=ir+audio+transmitterBut they do not even bother to publish the frequency range like 20Hz-20kHz and so it's likely to be less since this system is used for TV and not HIFI...Also I looked into a pair of wireless IR car headphones - that does the trick by definition, but need to be cracked open to get to the signal...Closest is this: (DE)http://www.elv.de/Stereo-IR-%C3%9Cbertragungssystem-SIR-1000-Teil-12/x.aspx/cid_726/detail_31653

author: David Hess
author_rank: Super Contributor
timestamp: August 31, 2014, 04:02:14 pm
content: One reason a direct modulation scheme over IR or RF may be preferable to a packetized digital scheme is that the delay will be constant and very short. Some IP solutions have so much delay as to require delay matching.

author: m3ga
author_rank: Newbie
timestamp: August 31, 2014, 06:57:06 pm
content: maybe these USB powered of the shelf components will cut it ;-) free line of sight between stations givenFM modulator 1x:http://www.amazon.de/TeckNet%C2%AE-Universal-Transmitter-s%C3%A4mtliche-St%C3%A4nden/dp/B00DG2KXQK/ref=sr_1_1?s=ce-de&ie=UTF8&qid=1409509672&sr=1-1&keywords=iphone+fm+transmitterFM demodulator 2x:http://www.amazon.de/Portable-Lautsprecher-Musik-Player-angegeben-Verzeichnis-2014-Gr%C3%BCn/dp/B00JVETNCC/ref=sr_1_5?s=ce-de&ie=UTF8&qid=1409510140&sr=1-5&keywords=mini+radioTotal cost about 40EUR - at least they look cool with the retro telescope antenna and the LED...LCD...I'm itching to try these toys out - would it be worth a shot or just bad noise....?

author: m3ga
author_rank: Newbie
timestamp: September 07, 2014, 02:53:15 pm
content: in a chip 20-20'000Hz for IR headphones etc:www.st.com/web/en/resource/technical/document/datasheet/CD00002597.pdf