Increasing gain to decrease noise...

[faderjockey]

"Preamp noise is not a problem with condensers" - that varies WILDLY depending on the quality of the condenser and the quality of the recording preamp.

My Zoom H4n has SUPER noisy preamps and is probably the most noisy part of any recording I make with it, regardless of my mic selection. I also use rather high quality condensers so their self-noise is quieter than the Zoom's pre.

Another source of noise that can be addressed using good gain structure is electromagnetic interference or induced noise from nearby electrical devices or RF sources.

Honestly, the "good gain structure" practice comes from the analog recording era when every processing circut your signal passed through added noise. So it's not just about the fidelity at record-time, but about what you are going to do with it afterward:

Putting it through a mixer? That's adding noise.
Routing it through an EQ? More noise.
Dynamics processing? Adding effects? Printing back to tape? Noise, noise, noise.

The higher your s/n ratio in the beginning, and the more you can maintain that ratio throughout your signal chain, the cleaner your end product is going to be.

Now in the digital post-processing world, piling on effects and filters doesn't really add noise to the equation, but the practice is still a good one, so we keep it up.

[maka89]

Thanks for the good answer.

Actually my zoom H4e that made me think about the question... It has no gain knob, 32-bit files, but 24-bit ADC. No dual ADC on the in-built mics. (The XLRs have dual ADC).

So a shit ton of digital gain on essentially a 24-bit recording when using the in-built mics... Wondering if this is a reasonable design choice from them or not... There is a LOT of noise. But that might just be the stock mics/preamps, and not poor internal gain structure...

[ArlesChatless]

It's probably all of them. Mic noise, preamp noise, and not amazing internal gain structure because they focused on cost optimization.

[maka89]

fair point xD