Low Input Levels Using Preamp

I am using audacity to record an acoustic guitar with a dynamic mic through a presonus audiobox. The mic has to be extremely close to the guitar and the input knob on the audiobox has to be all the way up for me to get a decent input level in audacity. Is there anything I can do in audacity to increase the input level so I don’t have to turn the preamp all the way up? Are there known issues when using preamps with audacity? Could this be an issue with the audiobox?

The audacity wiki on the subject did not specifically apply to using a preamp.

Any and all suggestions are appreciated. Thanks.

there is a gain adjustment in audacity
you can always amplify after the recording to make it louder

that is the way that such preamps and mikes are
you do need to be close
have a very loud signal - eg rock band

its a matter of physics
how much output can you get from a mike that sounds good
how much gain can a preamp have without other problems

twfm.com had an article in the last issue
you really need another preamp in front of your audio interface
in many real world situations


Such as? Model numbers?

It’s certainly possible to get an awkward combination of microphone and microphone amplifier. I have three microphone systems and only one has more than enough reserve gain to handle any volume level of performance. The other two run out pretty quickly and produce quiet shows.

The Shure X2U runs out too soon as does the Sound Devices Mix-Pre. The Peavey PV6 has enough spare amplification to deal with almost any shoot.


All other things being equal, you can use the Audacity tools to bring up a quiet show to more normal volumes.

Effects > Amplify > OK.

If you have something broken or sound problems in addition to low level, that’s more serious.


Thanks for the replies.

The specific mic I’m using is an Audiospectrum AS-420. I’ve played with placing it in different places while fingerpicking an acoustic guitar, and it isn’t picking much up unless I get right next to it. I’m not playing super loud, but it seems like I shouldn’t have to.

In the meantime I’ve made ample use of the amplify feature in audacity. Just wish I had more options with the preamp other than turning it all the way up. At half way, I get nothing.

Thanks again.

Grab a coffee and read through this thread. I believe it’s the longest in the history of the forum. This is Bruno trying to record his acoustic guitar…



Acoustic guitar is a “quiet” instrument so it needs close mic and high gain. I have no experience with dynamic mics, but you can read my experience in the thread koz mentioned.

There’s also an interesting SoS article about recording guitar (the link is somewhere in the middle of that long thread).

How close is the mic to the guitar (tell us numbers… cm or inches)? Which position? Classic mic placing for acoustic guitar is about 20-30cm in front of the 12th fret. Start from there.

I’ll check out that thread and play around with different things this weekend. Thanks for the ideas!