I’d like to record conferences with a PC running Audacity and a USB microphone, so that the wire can be longer without picking up noise and without having to use a battery-powered analog micrphone.
Which entry- to mid-level model would you recommend?
A USB microphone is always going to be limited to about 6 feet (2M) of cable before the data stream may become damaged. There are only painful, awkward ways of getting around that.
I did this job with an omni-directional microphone mounted on a heavy plywood board and floating on several layers of Duvetyne (towels work) in the middle of the table. The microphone is actually sitting in a shallow hole in the wood so it doesn’t roll around. The board is 32" on a side and is the recommendation of one of the microphone makers. It’s all painted black in actual use. Past the first day, everybody forgot it was there.
Because it’s a professional analog microphone, there is effectively no limit to the length of the microphone cable. I’ve seen them 100 feet or more. From there I plugged it into a small, well behaved sound mixer, a Peavey PV6, and then on to a computer soundcard. It was captured as a sound record of the meeting. It could hear the Polycom conferencing unit and so had all the voices from the other four cities as well.
Thanks for the feedback.
Being a digital device, I thought a USB microphone could be able to have a much longer cable to reach the computer :-/ I guess I’ll use an analog microphone, with a shielded cable, and keep the computer close to the speaker.
Does it have to be battery-powered, or is a static microphone good enough?
Is there an consumer model you would recommend?
Just a clarification. A professional-style microphone with balanced output can go long distances.
Your typical unbalanced consumer microphone is probably as limited in cord length as a USB device, but the failure mode will be different, the analog mic will have more issues with noise and hum pickup the longer the cable gets.
However there are some pretty inexpensive “professional style” microphones. Orange County Speaker sells a Chinese made knockoff of the ubiquitous Shure SM-58 (which retails for about $100) for $40 which isn’t bad (that may be one in Koz’s picture). But you will also need a suitable mic preamp or small mixer such as the Peavey PV-6 (which comes in a version with integrated USB interface). There are also a number of small Microphone - USB interfaces out there like the Behringer UMC-202, M-Audio MTrack etc. I would suggest some shopping and reading of reviews is in order.
Microphones that take a battery are generally what are known as Condenser microphone or Electret Microphones. As a group they tend to have lower distortion and flatter frequency response. The battery is there because the downside of this microphone design is an extremely weak signal from the microphone element itself, so an amplifier is needed right at the microphone element just to get the signal to a level that is similar to “normal” microphones. In most professional microphones this amplifier is “phantom powered” and when shopping for mic preamps and/or mixers you will see “phantom power” advertised for running this type of microphone. (Battery powered professional condenser mics used to be quite common before the 48V Phantom power standard took over)
The SM-58 (or copy thereof) in Koz’s picture is a “dynamic microphone” structurally it’s construction is not much different that the construction of a small loudspeaker (working in reverse). Generally they generate lots of signal without the need for an amplifier, are considerably tougher (will survive being parked inside a kick drum, or a wanna-be rocker screaming into it from an inch away), but will have more “interesting” frequency response. For vocals (and in particular for recording speech) they work just fine.
By the way Koz: If that’s an SM-58 (or one of the clones we had) in your picture, then it’s not “omni-directional”.
It’s the microphone I used for the design and it is the microphone I used in the C building which needed the directional pattern. In the A Building conference rooms, I used slightly older Radio Shack omni-directional dynamic microphones. Same plywood. Same black paint. No batteries.
We didn’t have enough heavy black cotton Duvetyne for between the plywood and the conference room table to absorb noises, so I bought Black Snuggle from JoAnn Fabrics. I love ordering that in person. “Excuse me. Can I get a little black snuggle, please?”
I don’t think RadioShack carries those mics any more. At least not the last time I looked. They did expand their on-line inventory. You can buy a news-gathering shotgun microphone there now. Should you have any news you want to gather.
How would I do that now…? I do have a design for a Radio Shack 3013 microphone. I mount it on a smaller board and put that on a towel in the middle of the table. That’s about 12" by 9". Unfortunately, it doesn’t directly connect to a mixer. It has built-in batteries and a 1/8" Tip-Sleeve plug. I built the adapters to plug them into our mixers.
And you do have to keep up with the batteries, but they’re omnidirectional and they do work nicely.
I have to think about actual available products. Omnidirectional microphones aren’t popular. You can’t take them into most difficult recording conditions.