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chester 9th March 2006 01:22 AM

Difference small and large diaphragm mics
hi all!

whats the main difference between small capsuled and large capsules in condensator microphones?

is there any difference to consider when buying.

thanks in advance

ciao boing

Kiwiburger 9th March 2006 01:31 AM

Diaphragm size is a tradeoff between accuracy and voltage (hence noise).

A large diaphragm is exposed to a larger piece of air. As we all know, sound in a room varies dramatically depending on position in relation to standing waves etc. Moving a mic just 1" can make a huge difference. A large diaphragm is slightly less accurate, but it obtains more energy from the greater surface area so it is louder. This means less gain is needed, so generally they are fairly low self noise.

A small diaphragm is more accurate, and also more sensitive to position (unless it's an omni). But the small surface area means it needs a lot of gain, and so they tend to be relatively noisy mics.

For many sources, e.g. vocals, accuracy is not good. It's like a closeup photograph of a super model. You don't want accuracy, you want some photoshop or airbrush. A large diapragm can help to 'flatter' a close vocal sound. Together with low noise, that's fairly desirable.

Some things might respond better to accuracy - maybe acoustic guitars. If low noise preamps are used, the higher self noise may not be an issue.

I don't like noise, so I use LCD as much as possible. Even on drum overheads.

lofi 9th March 2006 01:44 AM

well how much noise are we talking about ? modern sdcs and ldcs (at least cheap ones that i use) got plenty of output...


Kiwiburger 9th March 2006 03:07 AM

Exactly. The mike maker has to use more internal gain to make the sdc as hot as an lcd. Electronic circuits always add brownian noise, and the more gain, the more noise. This is before you add more gain with preamps and compressors.

Take Rode as an example:

NT2A and NT2000 (lcd) have an EIN of 7dBa.
NT3 (sdc) has an EIN of 17dBA.

That's an extra 10dBa of hiss, before you get to your preamp.

Quite low compared to vintage stuff, and certainly useable. But I don't like to add 10db of hiss unless I really need like the sound.

chester 9th March 2006 03:49 AM

thanks so far!thumbsup

lofi 9th March 2006 02:32 PM

understood and agreed

how does that compares to dynamics or ribbons ???

bobby yarrow 9th March 2006 03:42 PM

I use sd mics a lot. Bass response is better, off-axis response is generally better (comparing cardiod to cardiod), and they sound different.

pkautzsch 10th March 2006 12:44 AM

Especially the off-axis linearity is a very good point. An LDC called "cardioid" is nearly an omni at 150 Hz (but NOT a pressure transducer!), whereas an SDC cardioid stays a cardioid a long way down. Same thing with HF: LDC more directivity at 4k due to larger diameter and "PZM" effect. --> An LDC mic will colour the indirect sound much more than an SDC (btw: LDCs generally add more colour), and it will pick up more LF reverberation.
Modern SD mics have also very good noise values (e.g. Schoeps or DPA...), and they are suitable for more purposes. You might have one $1500 female rock vocal mic, one $1500 male rap mic, and 3 different $1500 overhead pairs. Or you have a pair of good SDs and add any colour you like later on (with 3 different $2500 EQs...). It's different approaches. And of course LDs look much cooler cooge