"Nasty resonances" in condenser mics.

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"Nasty resonances" in condenser mics.

Post by claz »

I've read the phrase "nasty resonances" a number of times in these pages, usually in reference to LDCs.

Under what real-world circumstances might I actually worry about inducing said resonances?

Would this contraindicate using the same mic multiple times in a project (e.g. to record stacked vocals)?

If you want a concrete point of reference, I'm thinking of my AT2035 as an example, whose published frequency plot is fairly flat until the high end -- but I'm also curious about the general case.
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Re: "Nasty resonances" in condenser mics.

Post by James Perrett »

The main issue is with poorly controlled resonances at high frequencies. In my experience this gives an effect similar to using an Aural Exciter which may sound good on some sources but not all. This also mainly affects mics which use the generic far eastern large diaphragm capsules rather than mics from manufacturers that use their own capsules.

Audio Technica have been in the mic business for a very long time and I wouldn't expect their mics to suffer too much from these problems. The frequency plot for your mic looks fairly well controlled.
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Re: "Nasty resonances" in condenser mics.

Post by Tomás Mulcahy »

Aural exciter is a very good description of what it sounds like. To me it sounds like there is an added whisper track shadowing the vocal. I've always liked the AT4033a because it does not do this, compared to stalwarts such as the C414 where it's quite apparent, or the U87 where it's not as pronounced but still there. I use an AT2020 which is a little less smooth sounding than a 4033 but it still does not do the whispery thing. Having listened to all the AT LDCs on Audio Test Kitchen, they all seem to sound very similar, getting smoother/ flatter as they increase in price, with the valve models have just the right amount of flattery.

In short, IMO the AT2035 is a very fine mic, performs far better than the price would suggest.
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Re: "Nasty resonances" in condenser mics.

Post by Sam Inglis »

Another possible cause of nasty resonances is ringing in poorly designed headbaskets. There is at least one Oktava model that is notorious for this.
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Re: "Nasty resonances" in condenser mics.

Post by Hugh Robjohns »

claz wrote: Thu Jun 23, 2022 11:03 pmI've read the phrase "nasty resonances" a number of times in these pages, usually in reference to LDCs.

Capacitor mics use a taught diaphragm which has a natural resonant frequency. The relatively large size of LDCs mean that resonance is typically near the top of the human hearing range. For SDCs it's usually just above hearing range and thus less of an issue.

There are various techniques to try and control the resonance, such as using rectangular or triangular capsules, centre termination, and so on, all to try and raise the frequency or introduce additional resonant frequencies which broaden the effect and make it less pronounced.

Under what real-world circumstances might I actually worry about inducing said resonances?

I'm not sure 'worry' is the appropriate response. It's a recognisable character of that kind of mic, to a greater of lesser degree. It tends to be more noticeable with close/loud sources that have well-defined and extended harmonic structures, and Sam's description of being like an aural exciter is a good one. The effect is a 'sizzle' around sounds...

If you hear it and don't like it, all you can do is swap the mic for something else... but often it's a welcome enhancement. And not a bad thing at all. It all depends on context and expectations/ requirements.

Would this contraindicate using the same mic multiple times in a project (e.g. to record stacked vocals)?

Good question! I don't think the HF resonance is the issue here. Rather, it's the overall character of the mic. If it has a pronounced character, the response peaks and dips will colour all the sources in the same way, and that might emphasise the mic's individual tonality in a distracting way...

But plenty of records have been made with stacked vocals recorded on the same mic... so it really depends on the specific mic.

If you want a concrete point of reference, I'm thinking of my AT2035 as an example, whose published frequency plot is fairly flat until the high end -- but I'm also curious about the general case.

Most AT mics are well-engineered and don't generally suffer 'nasty resonances' in the way described above — they're all quite smooth and well-controlled in my experience. But beware some of those using low-cost Far East LDC capsules....
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Re: "Nasty resonances" in condenser mics.

Post by Tim Gillett »

claz wrote: Thu Jun 23, 2022 11:03 pm I've read the phrase "nasty resonances" a number of times in these pages, usually in reference to LDCs.

Under what real-world circumstances might I actually worry about inducing said resonances?...

It's not like resonances we hear which get "excited" and seem to "take off" under the right stimulus. So a peak in a mic at say 10 kHz will likely be there regardless of the source and its loudness. It's more like an EQ fader boosted somewhat. The degree of boost doesnt change according to the source. It's not level dependent. That's my understanding anyway.

*Cross posted before noticing Hugh's more detailed answer.
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Re: "Nasty resonances" in condenser mics.

Post by claz »

Excellent, this all helps clarify what to watch out for, and what not to worry about! Appreciated as always.

Aural exciter is a very good description of what it sounds like. To me it sounds like there is an added whisper track shadowing the vocal.

Out of curiosity, is there a recording where I might hear this?
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