Background Fuzz

Cool_CM

I'm in the process of doing an electro accoustic music project trying to recreate this piece (http://en.wikipedia.org/wiki/I_am_sitting_in_a_room )with different microphones to compare and contrast the difference between the outcomes. The Mics we are using at the moment are an SM57, Sennheiser E835, a bad quality computer mic and a Gefell M930.
The basic idea is that you make a recording,play it back through a speaker and record the recording, which you repeat again and again until differentfequencies of the room begin to resonate, it's quite interesting when it works.
Trouble is we are having problems with background fuzz in the original recordings, have tried to turn down the mic levels but they keep on coming back. Obviously this is a big problem when playing it back through the speaker to be recorded again. We are using two laptops without soundcards and Soundforge(could just be a problem with the computer's current).
Does anybody have any advice on how we should go about trying to remove this fuzz? Any advice at all would be appreciated!
Cheers

cornbb

Interesting project!

What sort of audio interface/preamps are you using? A poor quality soundcard will add noise, try to get hold of a good quality interface. Ditto regarding mic cables. If the hiss gets drastically worse and worse with each iteration then this is probably the problem.

Use a 24 bit bitdepth to get an increased dynamic range and carefully adjust both the loudness of the speaker and the gain of the mics so that the waveform you record doesn't leave too much headroom, making sure it doesn't clip. Then again the loudness/gain settings will probably affect the rate the room's resonant frequencies become obvious so you may want a certain configuration for your project.

Also bear in mind that your laptop's cooling fans may add hiss or hum to the recording, try moving them to another room if possible.

have tried to turn down the mic levels but they keep on coming back.

Could you clarify that bit? Also feel free to post a sample of the noise.

studiorat

A really quiet pre amp and good omni mic. The dynamic mic's need too much gain and being cardioid will take more passes to reduce the clarity of the speech. Not using a sound card is going to make it noisier too. Also try make sure the gain structure for the playback system is as noise free as you can make it.

The original isn't exactly the quietest thing in the world either.

Contrary to what you might think the loudness of the playback will not change the way the resonances in the room differ, except maybe with respect to the frequency response of the equipment. The critical distance (the area where the reflected sound and direct sound are equal) does not change according to sound pressure level. It depends on the shape and size of the room and the absorbtion coefficients of the surfaces.

Cool_CM

I know this wqs a long time ago but thanks for the advice, ended up improvising and using an old tape recorder as a pre amp for all the different mics, the results are great, have used a few samples from them for electroacoustic compositions, can post up the results of all three if anybody is interested. Can anybody recommend as site for uploading audio with ease and i can post a link? Cheers.

frobisher

Did you manage to fix the problem?

studiorat

Cool_CM wrote: »

Can anybody recommend as site for uploading audio with ease and i can post a link? Cheers.

Gotta myspace?