Taperssection.com
Gear / Technical Help => Microphones & Setup => Topic started by: hobbes4444 on July 30, 2008, 02:11:00 PM
-
So I can't decide whether i want to run my HEB or AT933 hypercards at an upcoming outdoor show (lo-pro). Crowd noise is likely to be a problem, so HEB not ideal; wind could be a problem, so ATs not ideal. In the hat mount not really an option at this point. If I decide to run them both so that the HEBs will essentially piggyback on the ATs, could that cause any kind of weird interference (assuming the cables of each mic are still properly shielded)? I'm thinking it would be fine, but i'm wondering if anyone has run a similar set up maybe in an open situation for A/B purposes, etc.
-
I've run my DPA 4061's and AT853's at the same time and attached very close together for a comparison. I had no issues with interference whatsoever. FWIW.
-
seems like mics get 'stacked' all the time. I have never done it but I don't see why it would cause a problem.
-
Appreciate the feedback. Kinda what i figured, but thought i'd ask as I thought, but wasn't sure, if others have actually done this in the field. coolio!
-
I read something somewhere about having stuff near your mics could "disrupt the sound field" but I doubt that it would seriously affect what most of us are doing. Maybe in scientific measurements, etc. Try it and see! After all, look at some of the pictures of people hanging multiple pairs of mics off one stand in the Rig Pics section. Most of those folks are experienced tapers and if caused a problem I think the word would be out. Granted, you are talking about much smaller mics, but I bet its the same.
-
Anytime you place anything near a microphone you run the risk of issues with sound reflections. But I would be more worried about the lack of boundary between the two omni mics causing real phase issues with any recording you might make. You need something between the two omni mics in order to avoid this problem like your head. As long as you have a boundary between the two omni mics LEFT/RIGHT then you should be fine. The effects of the cards will depend greatly on how you mount them together.
Chris
-
Cybergaloot, what you read is perfectly true AND it can be quite audible in everyday recording practice; it's not just an "academic" point.
You can find this out for yourself by making some test recordings--set up your mikes on a stand or at some distance above a tabletop, then speak into them and move your hands slowly closer and closer to the mikes. You can get some weird sounds due to partial cancellation at various frequencies (phase conflict due to reflections).
Last night I was watching the wonderful TV series "Slings and Arrows," and at some point during some dialog that was filmed outdoors, I realized that I was hearing the reflections from what must have been the relatively small booth in which the dialog had been re-recorded in post production. Perhaps you've had similar experiences of being able to tell the size of the recording venue from the sound on the recording (particularly noticeable when the sound source moves). What we're talking about here is the same effect on a slightly different scale.
Primarily this affects the high and mid-high frequencies, since low frequencies have long wavelengths and can "flow around" most obstacles that aren't the large-scale, rigid structural features of a room. But the wavelength of 1 kHz is only about 13 inches, and for any given wavelength, anything larger than about half of that size can deflect a significant part of the wave, causing reflection or diffraction.
That's why small-diaphragm microphones (and small microphones generally) are preferred for the type of recording that tries to recreate an accurate picture of the original sound. A large microphone "gets in its own way" at high frequencies, and the point in the spectrum at which that starts to be a problem is lower, the larger the microphone is. For most conventional large-diaphragm microphones the problem exists in the 2 - 4 kHz range (the most sensitive range of human hearing!) and above; smaller microphones can "postpone" these problems for another octave or two. This affects not only the frequency response and polar (directional) response, but also the impulse response in a major way.
Solid objects placed near microphones can benefit a recording, too, as in the case of PZMs, sphere stereo recording or the Jecklin plate approach. But to know in advance what type of setup is likely to work takes a knowledge of physics and psychoacoustics. Otherwise you can count on needing an enormous amount of experimentation, with most of the results being less than optimal.
--best regards