Audacity Forum

Posted: **Sat Dec 25, 2010 11:52 pm**

garton wrote:Hi! I've been following this thread with great interest. There's clearly a great deal of knowledge in audio hardware here. I'd like to present a possible software-only (almost) solution.

Have you considered solving the many-headsets-connected-to-one-computer-problem using JACK? JACK ( jackaudio.org ) is a piece of software (open source, so it's free, and it's available for Windows, Mac and Linux) that, as I understand it, works as some sort of virtual patch panel, allowing you to wire virtual audio paths in your PC. And it works with multiple sound cards.

So my idea here is to get a USB sound card for each headset (they're really inexpensive, I found several on Amazon for less than $1) and a USB hub to connect them. Each of those acts as a sound card. Adding a USB sound dongle adds a sound card. Go ahead and use JACK to connect the inputs from all the headset microphones into a software mixer. Use JACK again to connect the output from the software mixer to the input of skype.

Please note; this is an idea. I have investigated it briefly, but I'm not sure it will work.

However, if it *does* work, it will solve this problem in a very elegant way. No soldering, no tabletop mixer, nothing.

(I've been looking into this beacuse I need to host a series of telephone conference calls where 3-5 people will be sitting in the same room, using headsets, with 2-3 other people calling in from other places. So far, we've been using a regular conference telephone with integrated speaker and microphone, with horrible results. The people who call in can barely hear the people physically present in the conference room.)

We know about JACK. There's some threads about it in the GNU/Linux forum. I'm a jack user in Linux, I don't use windows, so I don't know nothing about jack in windows. What operating system are you using? Are you using jack on Windows? Does it work?

USB sound cards for $1? Doesn't sound very promising... do they actually work?

Can you post a link to one of those devices?

Connecting more than 1 usb sound device to the same computer is known to cause troubles... Even if you manage to make it work it's expected some latency problems in the long run.

If you go ahead with your experiment let us know how it worked.

Consider starting a new thread about it... This is an old and very long thread... Starting a new thread would probably give you greater visibility and make things less... "fuzzy". Specially for those who haven't read the previous posts and are not willing to spend a few hours reading it all to understand what's this is about

Good luck!

Posted: **Mon Dec 27, 2010 12:06 pm**

bgravato wrote:We know about JACK. There's some threads about it in the GNU/Linux forum. I'm a jack user in Linux, I don't use windows, so I don't know nothing about jack in windows. What operating system are you using? Are you using jack on Windows? Does it work?

I've tried jack on both Linux and Windows but accomplished nothing on neither... I can't say that I really understand what I'm supposed to do with jack.

bgravato wrote:USB sound cards for $1? Doesn't sound very promising... do they actually work? Can you post a link to one of those devices?

They don't get very good user reviews!

http://www.amazon.com/External-Channel- ... 040&sr=8-4

Point beeing that even though maybe this particular ultra-cheap is not useful, you'll probably find something useful in a decent price range if you look around a little.

bgravato wrote:Connecting more than 1 usb sound device to the same computer is known to cause troubles... Even if you manage to make it work it's expected some latency problems in the long run.

That's what I hear, but it's not so easy to find out what those problems are, specifically. Since I'm not recording music, I don't need the sound cards to be very accurate. If I have 3-5 people in one room, each with their own microphone attending a phone conference, is it really a problem if the sound cards drift a little against each other? (This question is not rhetorical, I really wonder.)

bgravato wrote:If you go ahead with your experiment let us know how it worked.

Consider starting a new thread about it... This is an old and very long thread... Starting a new thread would probably give you greater visibility and make things less... "fuzzy". Specially for those who haven't read the previous posts and are not willing to spend a few hours reading it all to understand what's this is about

Good luck!

Thanks. I intend to do some experiments and perhaps start a new thread if there's any progress.

Posted: **Thu Mar 15, 2012 6:22 am**

I realize this is a REALLY old thread but if anyone's still out there lol...

I have a Yamaha mixer with preamps on 4 mic channels and I have the same problem with wanting to use three Plantronics Gamecom 367 Headset Mics with it.

I stared at the photos of the custom adapter boxes and diagrams for about a full day and decided there's no way I can even attempt building one without detailed instructions and pictures, etc.

I DID however find this guy's video that solves the same problem a different way. Is there any reason his method wouldn't work for me? He says something about not needing capacitors because the device has it's own and can separate the DC etc, etc.

"Making an adapter lead for a headset microphone so I can use it with an ordinary mic input"
http://www.youtube.com/watch?v=lh0RgXO4WWE

THANKS!!!

Posted: **Thu Mar 15, 2012 11:42 am**

acousticdj wrote:"Making an adapter lead for a headset microphone so I can use it with an ordinary mic input"
http://www.youtube.com/watch?v=lh0RgXO4WWE

My complaint about so many YouTube videos is that they frequently miss out important detail.
At about 5 minutes into the video he jumps from soldering the input socket to suddenly having the whole thing complete. Where did he connect the battery?

Fortunately there is a circuit diagram here:
http://www.epanorama.net/circuits/micro ... ering.html

: electret circuit.gif (6.29 KiB) Viewed 1479 times

He has missed out the capacitor on the assumption that the microphone input has a DC blocking capacitor capable of handling up to 9v on the input. That's probably a fairly safe bet for his old Akai reel to reel but I'd not like to rely on it for consumer grade modern equipment. Depending on the input design of the microphone pre-amp, 9v DC across the input could fry the pre-amp (irreparable damage). Even if it does not destroy the microphone pre-amp it could cause the microphone signal to be useless through either a huge amount of DC offset or high noise level. The purpose of the capacitor is to prevent DC going into the microphone pre-amp. The capacitor should be present.

Posted: **Thu Mar 15, 2012 12:46 pm**

This old topic is now locked.
The last two posts are now repeated here: http://forum.audacityteam.org/viewtopic ... 27&t=64269

For any issue relating to other parts of this topic, please start a new topic (on an appropriate forum board).

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