Conference Calls into Sound System

M

Marc Hayes

Freshman
Jan 12, 2011
59
0
6
Quad Cities, IL/IA
www.tnprod.com
We're working on a large conference room PA system and video system and the client wants to be able to take conference calls and be able to hear them loud and clear. Their thought was to be able to somehow input the call into the sound system we are putting in. Has anyone done this with positive results? If you've done it, what equipment did you use and how did you accomplish the task?

To me it seems like it might be a fight between intelligibility on both ends of the line between the loud PA reinforcement coming back through the phone line and back into the callers ears.

Any thoughts?

Thanks all!
 
Re: Conference Calls into Sound System

You will need something with Acoustic Echo Cancellation (AEC) as a minimum. BSS and Biamp, among others have offerings for this
 
Re: Conference Calls into Sound System

Dick Rees said:
A Gentner and mix-minus?
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+1

You're looking for what is known as a "telephone hybrid". It separates the send and return audio paths and allows the caller audio to be picked off separately from the listener's responses while also allowing external audio to be injected into the return feed.

Gentner, Comrex, and JK Audio are the companies I think of that make standalone versions. Other versions are available that use input card modules for DSP units.
 
Re: Conference Calls into Sound System

Marc Hayes said:
We're working on a large conference room PA system and video system and the client wants to be able to take conference calls and be able to hear them loud and clear. Their thought was to be able to somehow input the call into the sound system we are putting in. Has anyone done this with positive results? If you've done it, what equipment did you use and how did you accomplish the task?

To me it seems like it might be a fight between intelligibility on both ends of the line between the loud PA reinforcement coming back through the phone line and back into the callers ears.

Any thoughts?

Thanks all!
Click to expand...

I recently put one of these in, the client has frequent international phone conferences. The only issues have been callers with terrible sounding phones and accents.

JK Audio
 
Re: Conference Calls into Sound System

Matt Lillie said:
...The only issues have been callers with terrible sounding phones and accents.
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Same here…maybe a couple of bad connections or phone conference sessions that timed out due to inaction, but that's the main issue I have.

To the OP, here is my procedure for setting up with a hybrid:
1. Patch caller audio into line input. A note of caution: I've encountered hybrids with fried caller outs because someone patched into a mic jack without turning off phantom power; thus, my use of the line input.
2. Route all sound the caller needs to hear to an Aux Send (post-fader, preferably, so the channel muting follows).
3. Call in with your cell phone and then set your levels so that you can hear things "well" on the cell phone, but leave room to increase the volume if necessary.
4. While still on your phone, test the caller's audio into the sound system and get a good handle on what you might want to EQ out.
 
Re: Conference Calls into Sound System

Marc Hayes said:
We're working on a large conference room PA system and video system and the client wants to be able to take conference calls and be able to hear them loud and clear. Their thought was to be able to somehow input the call into the sound system we are putting in. Has anyone done this with positive results? If you've done it, what equipment did you use and how did you accomplish the task?

To me it seems like it might be a fight between intelligibility on both ends of the line between the loud PA reinforcement coming back through the phone line and back into the callers ears.

Any thoughts?

Thanks all!
Click to expand...

I think the best telephone hybrid is the Telos One because it has input, output and gain reduction meters as well as input and output gain controls on the front panel. It also has very clear names for "on hook" and "off hook" buttons, as opposed to Gentner or the Telos HX. It sounds great too. Unlike the Telos HX, it only works with POTS lines, you have to suffer with the HX for digital PBX lines.

Mac
 
Re: Conference Calls into Sound System

Is this for a production style event or an installed system for a conference room? Is there someone mixing or a bunch of mics on tables with automixing? A telephone hybrid addresses adapting to the phone line and line echo cancellation, but does not address acoustic echo cancellation for the receive audio in the room being picked up by the mics in the room. It sounds as though you may need something that provides all of these functions.

While Biamp, Polycom, BSS, Extron, Gentner, etc. all offer matrix DSP units with distributed echo cancellation, however getting those configured effectively can take some training and experience.
 
Re: Conference Calls into Sound System

mackerr said:
I think the best telephone hybrid is the Telos One because it has input, output and gain reduction meters as well as input and output gain controls on the front panel. It also has very clear names for "on hook" and "off hook" buttons, as opposed to Gentner or the Telos HX. It sounds great too. Unlike the Telos HX, it only works with POTS lines, you have to suffer with the HX for digital PBX lines.

Mac
Click to expand...

Another +1 for the Telos One ... my favorite to see on a job, out of the usual suspects.
 
Re: Conference Calls into Sound System

This is for an installed system, and there is no video component to this part of the project. (No videoconferencing.) The return path back to the caller are the 10 "delegate station" mics around the room. These are automixed by a BSS processor and output for recording only. Those same 10 mics do NOT get fed back into the house PA for reinforcement. So, I'm thinking the Telos unit might be the best tool for the job in this case? Or does anyone know a card for BSS that would suffice?

Thanks guys! This has been a big help.
 
Re: Conference Calls into Sound System

Marc Hayes said:
The return path back to the caller are the 10 "delegate station" mics around the room. These are automixed by a BSS processor and output for recording only. Those same 10 mics do NOT get fed back into the house PA for reinforcement.
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But would the far end audio end up getting picked up by the 'delegate' mics and fed back to the far end? If so then you might want to consider the AEC input cards available for the BLU-160 (see http://www.bssaudio.com/product_downloads/SoundwebLondonAppGuides/accoustic-echo-cancellation.pdf).
 
Re: Conference Calls into Sound System

Brad Weber said:
But would the far end audio end up getting picked up by the 'delegate' mics and fed back to the far end? If so then you might want to consider the AEC input cards available for the BLU-160 (see http://www.bssaudio.com/product_downloads/SoundwebLondonAppGuides/accoustic-echo-cancellation.pdf).
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Yes, you will need an echo cancelled input for every live microphone in the room. Any mics (or phones) not on echo cancelled inputs will defeat the AEC circuit and send echo to the far end.

There are several options of manufacturers, but the most common dsp boxes for this purpose are made by: Clearone, Biamp, BSS, Polycom (soundstructure) and Symetrix.
 
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