Why such low recording volumes with dynamic microphones?

This question is not limited to the Windows version of Audacity - I experience it under Linux Mint too, but I’m posting here because there are about 12 times more posts in this area than in the Linux area! I’m sure parts of this question have been answered before but I don’t see the complete explanation.

I’m trying to make some simple voice recordings using Audacity 2.3.3. I connected my entry level ProSound YU-34 dynamic mic. to the mic in connector on my laptop and found the recording level in Audacity was in the range of -54 to -42 dB, even with the level control at maximum - too low to be clearly audible on playback. Moving the mic to within about 0.5 cm of my mouth I gained about 6 to 10 dB but then had unacceptable levels of plosives and sibilants and the reocding was still far too quiet. I swapped to a high quality, but much older, Sony dynamic mic. with no improvement. I then tried connecting through a semi-professional quality Focusrite Scarlett USB interface, which has significant gain control. Even on maximum gain the recording ‘graph’ in Audacity was essentially a straight line.

But when I switched to a very cheap (almost give-away) combination headset/mic from Edifier I had to hunt around in Mint sound settings to find ways of not exceeding the 0 dB level in Audacity (the mic level control In Audacity was not adjustable) - that is, there was something like a 40dB gain…

So, why does Audacity see such a low volume from my dynamic mics? The ProSound mic is 600 ohm impedance and, I think, about -76 db sensitivity

It’s not just Audacity. Dynamic mics “generate” the signal by converting the (tiny) amount of energy from sound waves hitting the microphone diaphragm. Even if a microphone is 100% efficient at turning sound energy into electricity (which they are not), the maximum amount of electrical energy that they could produce would still be tiny.

“Condenser” microphones (and “electret” microphones) work in a different way. The microphone is supplied with electricity (anywhere between about 0.5 to 48 volts, depending on the type). The microphone does not need to “generate” electricity, only “modulate” the electricity that it is supplied with. They are therefore able to produce much higher signal levels. The signal level from a condenser microphone may be as much as 1000 times greater than from a dynamic microphone.

in the range of -54 to -42 dB,

I’m going to guess you have more than one problem, but the main problem is that stage/studio mics are not compatible with the mic-input on a regular soundcard or laptop.

From what I found on the Internet your microphone comes with an adapter cable. Does it have a [u]2-conductor TS plug or a 3-conductor TRS plug[/u]?

If it has a TRS connector, a TS connector should work “better”, and a [u]transformer[/u] is better than that but it’s still not “correct”.

Does your laptop have a dedicated microphone jack, or a single microphone/headphone combo jack? If you have a combo jack you need a [u]4-wire TRRS adapter[/u] to make the microphone connection. (You still need the 2-wire connection to the microphone itself.)

…If you are doing “serious recording” you’ll need a USB audio interface with a “proper” microphone connection ([u]example[/u]) and you might need a studio condenser mic. Or you can get a “studio style” USB microphone (AKA [u]podcast mic[/u]) might work for you.

Stage & studio mics have a balanced (3-wire) connection with an XLR connector. Studio condenser mics require 48V phantom power (supplied by the interface, preamp, or mixer). Computer mics use an unbalanced (2-wire) connection and the laptop/soundcard supplies 5V for an electret condenser mic.

Thanks for these explanations - I conclude that my dynamic mics are not suitable for use with the other equipment I have (Focusrite USB Audio interface, laptop mic in or desktop on board and sound-card interfaces), but the cheapo Edifier headset produces acceptable recording levels. The unacceptable noise levels that this headset also produces, at not extra charge, can be reduced to acceptable levels, for the intended application, using the Noise Reduction filters in Audacity. So I think I have a way forward. Thanks for the help.

my dynamic mics are not suitable for use with the other equipment I have (Focusrite USB Audio interface)

You said the mic was plugged into your laptop… It should work with the Focusrite interface. You might not hit 0dB, but if you’re getting -40 to -50dB with a strong voice fairly close to the microphone with the Focusrite cranked-up, something is broken or something is set-up wrong.

Oh… Is what I found on the Internet correct, that the mic cable has a 1/4" TS/TRS plug? If so, that’s most-likely the problem. Try a [u]regular XLR microphone cable[/u]. Your interface may have a connector that works with an XLR microphone connection or with a 1/4" line/instrument connection (which has less gain).