Cellphone to room speakerphone connection?
May 11, 2009 10:50 AM   Subscribe

Next month my hobby club will meet in a local library meeting room. It has no phone and no internet connection. The library cannot provide any phone line to the room. We want to phone a fellow hobbyist in another state and interview him about an aspect of the hobby in which he is an expert, for about 30 minutes. Can anybody think of a low/no-cost solution to providing speaker audio to boost the sound to an acceptable level?

There will be ~35 of us present. Trying to use someone's cellphone speakerphone is not going to provide enough volume for the conversation to be engaging or entertaining. We have laptops and decent computer speakers that can be pressed into service. Is there some simple hardware or software way of jacking a cell phone into a PC for 'public address' purposes? I'm not technologically phobic, but I don't own a cell phone, and so I apologize if the answer to this is obvious. (We will have plenty of people with cellphones to use.)
posted by eaglehound to Technology (9 answers total)
If you can 'tether' a phone (share the phone's net connection (3G, EDGE etc.) via bluetooth) you can make use of Skype or any other audio/video IM on the computer. Or, look at getting a 3G USB dongle - in the UK at least you can get Pay-as-you-go ones
posted by gregjones at 11:09 AM on May 11, 2009

I plug my iPhone into my PC's speakers sometimes and have taken calls - the audio comes through loud and clear through the speakers. You'd probably have to put someone close to the phone to relay questions (or maybe pass around a bluetooth earpiece?), but everyone should be able to hear the responses over the large speakers.
posted by jquinby at 11:17 AM on May 11, 2009

Cell phones generally have an audio-out port that is meant to be used with a headset. It's usually a "2.5 mm" jack; you should be able to get a cable at Radio Shack or any store like that to connect the phone to a boombox or a powered set of computer speakers (so long as they are the kind with a regular headphone-jack connection, not the kind that connect via USB). You don't have to have a computer in between.
posted by bcwinters at 11:26 AM on May 11, 2009

Is there a WiMax provider in your city, such as ClearWire? I believe ClearWire will let you do a 7 day free trial (or least you can cancel the service within 7 days at no charge). But don't tell them what you're up to, just act like you're interesting in ongoing service and ask read about their cancellation policy.
posted by neuron at 11:27 AM on May 11, 2009

Why not prepare the questions ahead of time and pre-record it to play back on a computer or tape recorder? It's not going to be as interactive as a live conversation but you have a month to ask for questions from members.
posted by JJ86 at 11:51 AM on May 11, 2009

Maybe some kind of bluetooth speakerphone?
posted by gregr at 11:52 AM on May 11, 2009

Use a hands-free kit to plug a mobile phone into your sound system.

Many mobiles have a wired hands-free kit available: one end plugs into the phone, the other end goes to a small microphone and some earphones. All the sound that would ordinarily go through the phone's microphone and speakers gets received/sent through those instead.

More interestingly for you, you can get versions that plug into the phone then, at the other end of the wire, have a small microphone and a standard headphone jack intended to let you plug in your own earphones. Just plug your speakers into the headphone jack and turn them up as loud as you need for everyone in the group to hear. Note that you're still using the tiny and not-very-sensitive microphone built into the wire. This could be helpful in avoiding audio feedback, but means that only the person holding the phone and wire (you?) will be able to talk directly to your expert.

Phone > Handsfree kit > double-ended audio lead > microphone input on speaker system.

The exact handsfree kit you'll need depends on what model of phone you'll be using, as each manufacturer has their own setup. So you'll need to decide that in advance. You'll also need to check exactly what you can plug into the speaker system - probably an audio lead like the above link, but what size? 3.5mm is the standard for earbuds, but bigger sizes (7.5mm) are common for professional microphones.

Er.. have you asked the library if they'd be willing to run a phone extension lead into the room for you? If you can borrow an actual speakerphone / conference call system and just plug it into an extension cable, it'd probably be much easier. Even if you supply the cable, if you can borrow the speakerphone it'll probably be cheaper than the handsfree kit, cable and mobile phone bill.
posted by metaBugs at 1:23 PM on May 11, 2009

Actually, maybe I'll second the advice to tether the phone to a computer. If the mobile phone and computer both have bluetooth, it should be pretty trivial to do. Heh, although it's a couple of years since I last did this, so my memory is a bit hazy on the exact details.

Turn the phone's bluetooth on, and make sure it's "discoverable", so the computer will be able to detect it. Then use the computer to connect to the phone via bluetooth. After connecting, the computer should give you a list of "services" that the phone can support. If you choose something like "audio gateway" (or "audio bridge"?), all of the audio from the phone gets sent through the computer. So a microphone plugged into the computer will send sound straight down the phoneline, and any sound coming out of the phone will be sent through the computer speakers.

I think any computer (windows, mac or linux) with bluetooth should be able to do this. Any phone that can support a bluetooth hands-free kit should be fine. Note that you don't actually need a bluetooth hands-free kit for this, just a phone that can support one - you're effectively using the computer itself as a handsfree kit.
posted by metaBugs at 1:36 PM on May 11, 2009

One issue with using external speakers with a cell phone is the interference from the wireless signal, that buzz and hum that comes over speakers as incoming calls arrive. Pretty problematic to even use an iPhone with a docking station/speaker arrangement.
posted by Jawn at 1:02 AM on May 14, 2009

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