I am interested in improving the mic coverage in several of our conference rooms at Cisco. Some rooms require ~4 additional microphones others might require upto ~8.
I asked a Polycom Engineer about their unbalanced RCA AUX I/O jack on their phones (really it's on their powersupply) & was told the following:
> Signal levels are the same for the AUX I/O jack on the
> SoundStation Wall Module, SoundStation Premier Wall
> Module, and the Satellite. "AC" refers to
> the frequencies between 200Hz and 3kHz.
> The following all refers to the AUX
> I/O signal unless otherwise stated.
> When acting as an input, the AC impedance is >20k.
> When acting as an output, the AC impedance is < 500 ohms.
> The signal has a DC impedance of 36K to +15V. Because of
> this, we recommend that connections to AUX I/O be AC-coupled,
> and that any external capacitor polarity take account
> of this +15V bias. Path Gain, Input: 400 mV RMS (-5.7 > dBm) at
> AUX I/O produces 480 mV (-4 dBm) RMS nominal at Tip/Ring into 600
> ohms Path Gain, Output: 340 mV RMS (-7 dBm) at Tip/Ring
> produces 400 mV RMS (-5.7 dBm) nominal at AUX I/OFor reference,
> saturation on the phone line is 0 dBm, maximum sustained
> signal generally allowable is about -9 dBm (which is very loud).
I also know [according to their web site] that their Preimer phone:
-has Automatic microphone mixing that intelligently directs one of three console microphones to whomever is speaking, and can switch among the mics up to 250 times per second, so not a word or nuance is missed.
-Dynamic noise reduction automatically adapts to background noise???
-full duplex capability adapts to the acoustic characteristics of any
room, with a separate echo canceller for each of its three console mics.
The question is, should do I need the SCM268,or should I spend the extra$ for a SCM410? Also should I even consider trying to hookup a SCM800 or an SCM810? Or should I forget using the Polycom phone & move to a higher end echocancelling Gentner AP400/AP800? e.g. Will I hear clipping & have poor intelligibility?
The question is, should do I need the SCM268,or should I spend the extra for a SCM410?
* The SCM410 will provide better intelligibility because unused mics are attenuated. We feel it is worth the extra money.
Also should I even consider trying to hookup a SCM800 or an SCM810?
* Don't use the SCM800 - too many open mics. The SCM810 is just like the SCM410 but with more inputs. Do you require the additional inputs?
Or should I forget using the Polycom phone & move to a higher end echocancelling Gentner AP400/AP800?
* Suggest you ask Gentner or someone else that has a Gentner.
Will I hear clipping & have poor intelligibility?
* The Shure mixers will not "clip" syllables and they should improve intelligibility.
Can I get a loaner to test it out before I buy one/some?
* The local Shure rep may be helpful.