Gear / Technical Help > Recording Gear

Best Mic for Lectures?

<< < (2/2)

DSatz:
My first question would be whether the podcast is delivered in stereo or in mono. If by chance it is delivered in stereo, then by all means, record the lectures in stereo and keep them that way when you mix! The recordings will be far more engaging, and the words will be far more intelligible to your listeners for any given microphone type or miking distance that you use.

Your facts about the higher output levels of condenser vs. dynamic mikes are basically correct, but the conclusions that you draw from them would be relevant only if for some reason, your recording device can't handle the signal levels that a [studio] condenser mike would put out in the type of recording that you're doing. It would be a concern if your mike was very sensitive and was placed inches from a guitar amp during a heavy metal show. But you're talking about voice pickup from a distance, where the signal levels are much, much lower. Any preamp / mixer / recorder whose inputs could be overloaded under those conditions would be pretty unusable for live recording in general.

The most important thing is not the choice of microphone but its placement. If you can get your mike onto the podium or tap into the P.A. system, fine. If you can't, (as a distinct second choice) aim the microphone at a P.A. system loudspeaker from close range--12" to 18" away, maybe. The reverberation of the hall is your dire enemy, and it starts MUCH closer to the source than you probably realize--the human brain is very good at filtering that stuff out, but it depends on having the input from two ears and (to some extent) your eyes as well. Most people are unaware of the extent of that until they start recording and listening to the results.

Once you have a clean, "dry" (= little or no room echo) recording, you can equalize to taste as you mix the recorded signals into your podcast--for speech recording, this usually means reducing the "boomy" low- and low-mid-frequency sound due to microphone proximity and/or the P.A. loudspeaker if you ended up miking one of those. As a side benefit, a low cut or rolloff will also reduce any handling noise and some environmental noises.

Finally, back to the choice of a microphone: As I said, stereo is greatly preferred; one-point stereo microphones are quite common, and nearly all will have the kind of curtailed low-frequency response and moderately boosted mid-high-frequency response that are your friend for voice recording. Most of these nowadays are "electret condensers" which is a nice compromise of economy and operating simplicity--many can be powered directly by your recorder, while others may require an internal battery, but the battery should last a good, long while--just be sure not to leave a battery in a microphone (or anything else) for months on end; when they eventually leak, the equipment can be ruined.

If you're recording in mono, then the "driness" of the recording (= miking close to the source, with a directional microphone that's accurately aimed) becomes urgent, because you've lost the ear/brain processing that makes such recordings easily intelligible. The thing is, directional microphones are also more subject to handling noise, solid-borne sound, breath noise, and "popping" on consonants (p, b, etc.) than typical omnidirectional microphones are, so those are issues to consider. One possible compromise that might be useful is boundary layer (or "pressure zone") microphones, which can create the effect of being somewhat closer than they really are; there are both mono and stereo versions of those, at all levels of quality and cost.

--Over the years I've done a fair amount of documentary sound recording with professional gear, and I have some pride at the quality of many of those recordings. But the most important thing is to get there and get a clear enough recording. Years later when people are trying to remember exactly what was said or done (particularly if some or all of the participants are no longer around), even a noisy, mono cassette recording with a poorly-placed, third-rate microphone is something to be immensely grateful for.

--best regards

kuba e:
Thank you for nice explanation. This is helping to clarify the principles. I agree, recording the lectures in stereo has better results, it is more pleasant to listen. A minor disadvantage is when the lecturer moves to the side and you have no possibility to angle mics.  But the stereo image can be centered in post processing. Or, we can use only one channel of stereo as mono recording, then all will be in the center.

Navigation

[0] Message Index

[*] Previous page