Cheap conference room audio for non-profits
March 28, 2013 11:13 AM   Subscribe

I need a better audio setup for a projector in a conference room for a non-profit with no budget. Seriously: we're poor.

This question has been asked before, a few years ago, but there wasn't enough detail to help me.

We have an adequate projector, but I want to first mount it on the ceiling as a permanent installation, so someone (usually me) doesn't have to set it up every time, and all the cables end up back in the right bag instead of in the trash. I can do that part, and run the video cable down the wall and up to a table where a laptop can be placed.

Audio is a problem though. We have an old Samson wireless mic, with a small Bogen amp, which is underpowered and feeds back, but it works. But we can't run laptop sound. We have to set up a pair of cruddy computer speakers and plug into the headphone jack on the laptop, but the whole setup is cumbersome and unconnected.

We've even had people try to hold the mic up to the laptop speakers, or the phone handset, which makes me cry, and people's ears bleed. We've tried a big satellite conference room phone, but people steal it (anything that's not bolted down disappears within the hour).

What I guess I'm dreaming of is a wireless gizmo that plugs into the laptop headphone jack and connects to the Samson wireless receiver, or equivalent. I've seen cheapo USB transmitter/receiver sets, but I can't guarantee a free USB port on the computer, either -- it's old.

I'm also hampered by the fact that I don't know what the eff I'm doing -- I understand the computer and video end of it, but anything beyond a 1/8" headphone plug on the audio side confuses me -- I look at the specs and see all this "balanced output" and "600 Ohm" and I dunno what that is. I need someone to talk to me like I'm stupid.

And, as I mentioned, we have almost no money for this. In the other thread someone mentioned spending $750, and that's not likely to happen. $150 might fly.
posted by Fnarf to Technology (27 answers total) 1 user marked this as a favorite
Do you have the model number of the amp ? Cant you just get a headphone to mic input cable?
posted by majortom1981 at 11:40 AM on March 28, 2013

As the former director of a non-profit, let me suggest something. This is the perfect opportunity to do a specific "ask" to some of your supporters for both the expertise to get this set up correctly and for the funding to afford decent equipment. I found that people loved knowing exactly what they were donating for and would feel good about meeting a specific need.

Send out an e/mail, see what happens, it can't hurt. It might actually be an easier solution than trying to do it on the cheap.
posted by HuronBob at 11:41 AM on March 28, 2013 [1 favorite]

What does this amp (by which I assume you to mean a guitar-amp-like box with an amplifier and speaker in it) have in terms of inputs? It's not wireless, but you might get away with a long mini-trs to xlr cable (search Amazon for something like "stereo to mono mini trs to xlr").
posted by paulg at 11:43 AM on March 28, 2013

Some more details would be useful - what speakers do you have? Make & model of the Bogen amp? Of the wireless mic?

If you could give us this info it would be really helpful in determining if you can use your existing stuff plus maybe $150 or less in new pieces, or if you're just kinda borked and need to think about starting over (which could still possibly happen for $3 - 400.
posted by soundguy99 at 12:19 PM on March 28, 2013

I did a quick search and bogen sells a wide range of amps.

The smallest one I found has a aux rca port. If you have that model all you would need is a mono to stereo rca adapter and a headphone to rca cable.
posted by majortom1981 at 12:26 PM on March 28, 2013

Response by poster: The amp is in a closet , wired to the overhead speaker. Dunno what the speaker model is; it's just a generic round overhead speaker, the same kind our phone announcements come out of. You wouldn't want to listen to music out of them, but they're adequate for speech. There are three of them, in different parts of the room and one out in the hall for overflow. The amp is a Bogen C-10. It's not a guitar amp, just a little brick thing.

It does indeed have an aux RCA jack. The problem is getting to it; that's why I thought wireless. The way the room is laid out, the laptop has to be on the far side of the room or on a table in the middle, so a cable would have to run up one wall, across the ceiling, and down another wall and into the closet. The room is large, with a high ceiling; that could potentially be a run of a hundred feet. Is that even possible?

Other part numbers: speaker selector unit (I dunno what it's called, it switches the various speakers on and off): Russound SS-4. Mic and receiver: Samson UR-1. All of this was installed by someone else many years ago.

The "ask for a grant" idea is a good one.
posted by Fnarf at 12:52 PM on March 28, 2013

Response by poster: Rodrigo Lamaitre, the current setup is adequate for a speaker's voice -- it's the laptop audio I'm trying to capture. We increasingly get people who want their videos or Gotomeetings or whatever to play for a large group. The projector itself has audio that's no better than the laptop's.

I suppose I could run a separate set of computer speakers out of the projector, and mounted up in the ceiling next to it?
posted by Fnarf at 12:56 PM on March 28, 2013

Response by poster: What about those remote guitar thingies? What are those called? Plug into the guitar via 1/4" jack, then transmit wirelessly? I could get an adapter and plug that into the laptop instead, right?
posted by Fnarf at 12:57 PM on March 28, 2013

If I read the instructions right you should only need a 1/4 to 1/8 adapter. this would plug into the pc and the wireless pack with the 1/4 adapter should plug into that. This should work since it works with guitars.

if not use a mini xlr cable to headphone cable to connect the computer to the wireless pack.
posted by majortom1981 at 1:22 PM on March 28, 2013

The instructions state it comes with 2 of the wireless packs one for instruments and one for a mic. the instrument one just needs a converter adapter for the pc.
posted by majortom1981 at 1:23 PM on March 28, 2013

Response by poster: The instructions state it comes with 2 of the wireless packs one for instruments


Wish me luck finding the other wireless pack. That would be ideal, but this thing was installed two employees ago.
posted by Fnarf at 1:33 PM on March 28, 2013

how is the mic connected ? should either be a thing connected to the bottom of it or connected via cord to one of the packs
posted by majortom1981 at 1:57 PM on March 28, 2013

Response by poster: It's an all-in-one unit. Samson Ch-U2. If you unscrew the cover it says "TRANSMITTER MODEL UH1" inside, but that's not removable from the microphone itself.

Samson makes a whole range of radio guitar thingies. Would one of them work with my old model receiver? I know nothing about frequencies and so on. Also, are guitars comparable volume-wise to computers? I wouldn't want to get a functioning setup and blow the whole thing apart, or not be able to hear it.
posted by Fnarf at 2:09 PM on March 28, 2013

Response by poster: The mic is apparently also known as a Q-Mic.

The guitar transmitter that would have come with is a UT1G. That's the one that has the 1/4" guitar plug. The UT1L is a similar transmitter, only with a XLR or mini-XLR jack for a microphone, either a handheld or a lapel mic.

Is there such a thing as a 1/8" headphone jack to mini-XLR adapter or cable? I know nothing about this stuff. The reason I ask is because I found a UT1L on Ebay. If I can get that work, I think I'm all set.
posted by Fnarf at 2:23 PM on March 28, 2013

Response by poster: Except the one on Ebay says "CH 3" and my mic says "CH 2".
posted by Fnarf at 2:34 PM on March 28, 2013

Best answer: I think your best bet would be to get a long rca to headphone cable and plug it into the amps rca aux input.
posted by majortom1981 at 2:42 PM on March 28, 2013

Response by poster: OK, so here's a stupid question: which is better, a 100-foot 3.5mm headphone cable with an RCA adapter on one end, or a 100-foot RCA cable with a 3.5mm headphone adapter on one end?
posted by Fnarf at 3:13 PM on March 28, 2013

Best answer: Whoa, dude. Deep breath. This is solvable, but you gotta give us (well, me, anyway), a minute to organize my thoughts.

Except the one on Ebay says "CH 3" and my mic says "CH 2".

Won't work. The Samson Series One stuff is (as far as wireless goes) super-cheap, is pre-programmed with no ability to change channels.

The instructions state it comes with 2 of the wireless packs one for instruments and one for a mic.

I am not seeing this. The manual (pdf link here) explains how to use any/all components of the wireless system, but that doesn't mean the unit was actually sold with all possible components. It's very common in the audio world for one manual to cover multiple models or variations of a model.

You may have more serious problems with your wireless, however, assuming you're in the U.S. Making a long story short, as part of the transition to digital broadcast of over-the-air free TV channels, the FCC "took over" the "700 MHz band" of airwaves, which actually means 698 to 806 MHz. See this page from the FCC. Looking at page 6 of the Samson manual I linked above, it says the Series One wireless frequencies are from 801.375 to 804.750 - i.e., within that 700 MHz band. Which means, I'm sorry to say, that your wireless system is technically illegal. (Also pretty old, as the transition happened over 2009-2010, and all reputable & semi-reputable wireless companies had seen the writing on the wall and stopped selling wireless systems in that range for at least a couple of years before that.)

Now, I won't say that the FCC is gonna come crashing through your door any minute, but it is possible (although unlikely) that your wireless may interfere with something that's legally supposed to be on that channel, and the FCC may investigate & fine you. More likely is that something broadcasting legally on that channel will interfere with your wireless, causing your signal to drop out or horrible bursts of loud static and such.

Don't spend another penny on your existing wireless system. If you wanna use it, that's up to you, but buying anything else associated with it is probably a waste of money.
posted by soundguy99 at 3:20 PM on March 28, 2013

Response by poster: OK, the plot thickens: our existing microphone is illegal. We were supposed to have stopped using it as of June 12, 2010.

So I guess we have to get something else anyways. Sigh.
posted by Fnarf at 3:21 PM on March 28, 2013

Response by poster: Ah, soundguy99, we were writing at the same time. Yup. We need to come up with a whole new way of doing things.

The funny thing is, I found the BOX that the Series One came in, and it did indeed once have both transmitters in it. The space is there in the styrofoam. But the part itself is missing. Which doesn't matter since the whole thing is against the law now...

Now I'm looking at a Samson Concert 77 rig, which is pretty much the same thing but in a legal frequency.
posted by Fnarf at 3:24 PM on March 28, 2013

Okeydokey - so if I'm reading you correctly, the Bogen C-10 mixer/amp (pdf manual here) is sitting in a closet, outputs connected to the Russound speaker selector, output from that to speakers in the ceiling.

Where is the receiver for your wireless mic ? How is it connected to the Bogen?
posted by soundguy99 at 3:42 PM on March 28, 2013

Oh yeah, and "space in the styrofoam" still doesn't mean it came with more than one transmitter - it's cheaper to just manufacture one box & styrofoam mold, then load the box with only the components sold.
posted by soundguy99 at 3:44 PM on March 28, 2013

LIke I said I think computer wise your best bet would be to get a rca to headphone cable and plug the pc into the bogin c-10 mixer. then use the $150 to get a new wireless mic

That's the easiest way without having to get a new amp.
posted by majortom1981 at 3:55 PM on March 28, 2013

Response by poster: It was listed on the box copy as well. Whatever, it doesn't matter because that whole setup is going into the trash anyways.

Yes, you have the setup correct. The Samson receiver is sitting on top of the Bogen and Russound, in the closet. It's connected with a 1/4" jack into the back of the Samson that has had the other end cut off, and the bare wires screwed to the MIC 1 posts on the back of the Bogen.

I am assuming I can slap an updated Samson or other wireless mic/instrument receiver in place of the existing one, use the same cable, and be good to go.

However, there is a very ominous tag hanging from the Bogen's power cord that reads "CAUTION: Do Not Attempt to Operate Unless You Read and Thoroughly Understand the Instructions: DO NOT ASSUME ANYTHING!", which means I probably broke it already just thinking about it.
posted by Fnarf at 4:02 PM on March 28, 2013

Best answer: I am assuming I can slap an updated Samson or other wireless mic/instrument receiver in place of the existing one, use the same cable, and be good to go.

Pretty much, yeah. 1/4" can be tip-sleeve (TS) or tip-ring-sleeve (TRS), but in practice with less-expensive equipment it doesn't really make much difference, and I wouldn't worry about it unless/until you plug it in & there's a problem.

Now, how to get audio from a laptop to the Bogen.

First consideration - is the plan to have a wireless microphone for the presenter and then also be able to have sound from the laptop? This is totally do-able with your system, you'll just need to start to utilize the MIC2/aux input on the Bogen.


which is better, a 100-foot 3.5mm headphone cable with an RCA adapter on one end, or a 100-foot RCA cable with a 3.5mm headphone adapter on one end?

Neither. They're the same cable. This is "unbalanced" cable, and the problem is that once you get over 25', or especially over 50', this kind of cable is subject to picking up all kinds of noise and interference from environmental radio waves and electromagnetic fields, i.e. from the fluorescent lights in the room.

So you want to run "balanced" cable, otherwise known as "microphone" or "XLR" cable.

The other problem is that microphones put out a very very low-level signal, while the 1/8" output from your laptop puts out a much hotter signal, so the MIC inputs on the Bogen are set up for mic level signal input, and a direct connection from the laptop to the mic input is likely to be distorted. Luckily there are devices, called DI's (for Direct Injection) that convert from line level to mic level and from unbalanced to balanced.

I'd suggest the Whirlwind podDI for your purpose. Street price about $80. Plug a straight 1/8" to 1/8" or a 1/8" to dual-RCA cable from the laptop to the DI, the DI converts to mono properly, and then an XLR cable to the Bogen, and a short XLR to bare-wire cable to the MIC 2 input.


Well, first, I can't find a manual for the Concert 77 series any-damn-where, not even on the Samson website, so I gotta say I've got some doubts about how easily this particular wireless system would work for you - the devil's in the details, as they say, and without a manual I've got no details.

Anyway, the general rule is that you can only have one transmitter per receiver turned on at any time. Some wireless (generally cheaper ones) will allow you to make a trade-off of having two transmitters on simultaneously at the expense of reception, but the rule is something you should be aware of as you shop for wireless. Note that this is such a basic idea that a lot of manuals will not specifically tell you "YOU CAN'T DO THAT." So if you want to have a wireless mic for the presenter and a wireless connection for the laptop, you might actually have to buy 2 wireless systems.

Is there such a thing as a 1/8" headphone jack to mini-XLR adapter or cable?

Yup, apparently, although it seems they're pretty unusual. I found one here, but to be honest I've no idea why it says it's for AKG headphones and I've never encountered this particular website before. It might be worth some web-searching/call/email to some established pro audio companies like Sweetwater, Full Compass or B&H PhotoVideo to see if they can get you this cable. You might pay another $10 or $15, but they're all very reputable companies.

But your idea is spot on - get a cable like this, plug from the laptop to a beltpack wireless transmitter, then from the wireless receiver to the Bogen.

which means I probably broke it already just thinking about it.

Hey, as long as you haven't let the Magic Blue Smoke out of the unit, you're fine.
posted by soundguy99 at 6:25 PM on March 28, 2013

Response by poster: This is fantastic information, thanks.

I've already prevailed on you too much, but I have one more question:

I'm seeing lots of "dual" and "quad" systems, and I'm wondering, are they genuine dual-receiver systems, that can take two simultaneous non-interfering transmitters, or are they the junky kind you refer to?
posted by Fnarf at 10:36 AM on March 29, 2013

Mmm . . . hard to say with 110% certainty without knowing the manufacturer & model, but -

"Dual" can be a little tricky; "dual diversity" is a phrase that gets used a lot, but it just means "2 antennas for better reception", no relation to how many transmitters can be used simultaneously. "Quad" you're probably in safer territory.

It's certainly possible to build reasonable-to-excellent quality wireless receivers small enough to fit 2 or even 4 in one 19-inch rack space housing.

Quickie rule-of-thumb - how many screens are on the receiver? Since you can't have more than one wireless system on the same channel without interference, true dual or quad receivers need to give you the ability to set the channels on the receiver & transmitter, and most of them are built with one screen per receiver. So two receivers in one housing will have 2 screens, generally.
posted by soundguy99 at 2:14 PM on March 29, 2013

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