Please Evaluate my $1,500 Classroom Miking Proposal

[Cornelius Allen]

"a freak'n mess"

I also agree. I just watched two demonstration videos showing how a panel discussion audio setup benefited. The first video showed of the use of auto mixer turned off compared with the second video showed the auto mixer turned on. Huge difference in audio quality. I don't want subpar results.

So, I have decided it's best if we hold off on a cheap audio "solution" until we can afford a much superior (and expensive) one. That means that we'll have the lavaliere-miked lecturer repeat questions from those inside the classroom.

I thought about expanding our future "wishlist" to three Shure SCM410 automatic mixers (since we will never have a dedicated person for audio) to accommodate 12 condenser mics, like the Shure CVG12-B/C Gooseneck along with their separate desktop base with built in foot-long XLR cable

The only question I have is how am I going to reconcile the "Last Mic Lock-On" feature if the only mic we want "locked on" is the lecturer's? Some kind of daisy-chaining or something? And it appears that since three of those mixers will have to be purchased, then I'll have to get another mixer to take the feed from all three of these.

Cost of this superior setup: ~$4,020

[Brian P. Reynolds]

The is also an 8 channel version of the Shure auto mixer and they do have a cascade function so multiple units work as one.....no need for a summing mixer.
The last mic open function is fine, when the lecturer starts it will switch to that mic.

[Rick Reineke]

Auto mixers are fine (well almost), if everyone is close mic'd.. but I don't think that would work in the OP's case.

[Cornelius Allen]

Auto mixers are fine (well almost), if everyone is close mic'd.. but I don't think that would work in the OP's case.

Actually I've modified the plans to have everyone mic'd. All the students in the classroom will have a dedicated microphone. I've axed the original plan to have one mic per two students.

The is also an 8 channel version of the Shure auto mixer and they do have a cascade function so multiple units work as one.....no need for a summing mixer.
The last mic open function is fine, when the lecturer starts it will switch to that mic.

I've been looking for those, but they all have euro/phoenix block connections which is unusable for me. I take it that is for a fixed installation, whereas my setup is mobile so I need XLR or 1/4" connections, which the 8-channel versions of those mixers do not offer.

With that said, if I have to opt for three 4-channel SCM410 mixers, what am I going to do about the the "last on, locked" feature that will essentially leave one mic open per mixer. I only want one to be open (the lecturer's).

[Greg Miller]

I share Rick's reservations about this setup... All the students should be miced as closely as possible.

I also think it's very important that all the desktop mics have very good isolation mounts, otherwise the thumping of the desks, when people type, might confuse the gated mixer. Using a fairly steep HPF on all the student mics might help with this, too.

It would be ideal if you could somehow get the equipment on a trial basis, to be sure it will do what you want in this particular situation, before making a final and irrevocable purchase. Again, a trustworthy local dealer is worth a million bucks in a situation like this.

[Greg Miller]

Originally Posted by Cornelius Allen

they all have euro/phoenix block connections which is unusable for me. I take it that is for a fixed installation, whereas my setup is mobile so I need XLR or 1/4" connections, which the 8-channel versions of those mixers do not offer.

If this is for a portable setup, have the mixer(s) installed in a road rack/case. Also, mount a panel with the XLR connectors you need, and permanently wire the connectors to the mixer with short pigtails.

[Cornelius Allen]

Originally Posted by Greg Miller

I share Rick's reservations about this setup... All the students should be miced as closely as possible.

I also think it's very important that all the desktop mics have very good isolation mounts, otherwise the thumping of the desks, when people type, might confuse the gated mixer. Using a fairly steep HPF on all the student mics might help with this, too.

It would be ideal if you could somehow get the equipment on a trial basis, to be sure it will do what you want in this particular situation, before making a final and irrevocable purchase. Again, a trustworthy local dealer is worth a million bucks in a situation like this.

Do you know where I could get "isolation mounts"?

I think the trial basis purchase is a good idea. Thanks for that.

[Cornelius Allen]

Originally Posted by Greg Miller

If this is for a portable setup, have the mixer(s) installed in a road rack/case. Also, mount a panel with the XLR connectors you need, and permanently wire the connectors to the mixer with short pigtails.

I am aware of the portable rack case, but I'm not sure about the XLR connector panel. How is that done?

[Steve House]

Originally Posted by Cornelius Allen

I am aware of the portable rack case, but I'm not sure about the XLR connector panel. How is that done?

Visit an online pro-audio retailer such as Full Compass and search the site for XLR audio patchbay.

[Rick Reineke]

Sort of like a patch bay w/ XLRs.
TecNec TecNec XLR To XLR Patch Bays Patchbays & Panels Accessories at Markertek.com

I'm not sure about the 410 auto-mixer, but some have a priority channel mode, which is locked on.
Depending on the mics, shock mounts are plentiful.. I don't think there are that many options for goose neck mics, some come with a shock mount base.. others must be 'permanently' installed.. using a hole saw..
<rant> My problem with goose-neck mics was they're very susceptibility to plosives.. folks 'eating' the mic. to the point of bottoming-out the diaphragm.. major distortion.. and not easily repairable after the fact. </rant> If the speaker is eight or so inches away, they're OK. So again, the auto-mixer may or may not work good.. even in best environment, they're not fool-proof and must be set-up properly.. so an experienced audio tech should still be enlisted.

[Greg Miller]

You don't exactly want a patch bay, though. You want a panel with eight (or more) XLRs mounted in the panel, and pigtails soldered on the back end of the XLRs. They you connect the bare end of those pigtails to the screw terminals on the mixer. Again, a local retailer should be able to source these for you, and, in fact, should be able to mount the mixer and panel, and wire everything so you're ready to "plug and pray."

[Cornelius Allen]

Does anyone have a better (priced) suggestion than those wildly expensive Shure gooseneck condensers I sourced? With mic and base, those are costing ~$160 per unit, which I think is unnecessary given that we are only capturing brief, intermittent speech.

[Richard Crowley]

PyleHome - PDMIKC5*-*DJ Equipment*-*Microphones
Street price appears to be ~$30 and widely available.

[Rick Reineke]

There ya go. Sensitivity ain't too bad. (-40dB)
Don't expect top shelf performance for $30 though.
Probably very susceptible to plosives and table noise. Likely unbalanced and a 1/8" plug as well.

[Greg Miller]

Originally Posted by Cornelius Allen

With mic and base, those are costing ~$160 per unit, which I think is unnecessary given that we are only capturing brief, intermittent speech.

I can give you a good deal on a couple of intermittent microphones.