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When recording with my new mic, the Shure SM7B, everything that gets recorded is extremely quiet and gets a ridiculous amount of static after upping the gain and using a compressor.

I recorded it with an Akai EIE Pro interface.

Could this be because the preamp in the Akai is not up to par and that I need an external preamp or interface with a better preamp? Or is it another problem?

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  • Don't forget the possibility of a bad microphone or other equipment. Have you tried plugging the mic into something else? Have you tried a different mic with the interface?
    – Friend Of George
    Oct 1, 2012 at 20:35
  • No I have not. I only got my EIE right now. I'll have to try that out. Eventually going to buy a mixer or a new interface anyways after I build my PC, but can't wait till then! Will have to see if someone I know has something I can try it out on.
    – Travis Dtfsu Crum
    Oct 1, 2012 at 20:55

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Looking at the specs of the Akai EIE Pro (from here), this is the relevant section:

ANALOG INPUTS
Mic gain (MIC): +9dB to + 51.5dB

The mic preamp in the Akai is capable of putting out up to 51.5 dB of gain.

Looking at the spec sheet for the SM7B, search for "Output Level." You'll see that the output level for the SM7B is -59.0 dB. This means that even at max volume (not recommended) loudest the Akai can get the SM7B is -7.5 dB. You start hitting the top 20% (the hissy section) of your preamp gain at ~40 dB. This gives you up to -19 dB with clean gain.

Simply put: Your preamp isn't capable of putting out enough gain to support the SM7B. You need between -18 and -12 dB of clean signal to get a good tracked recording.

The options you mentioned such as external preamps and new interfaces are both valid options, and probably the best plan in the long term. However, preamps and interfaces can get expensive, so I'll suggest a third option.

You said you tried boosting the quiet signal by adding a gain or compression plugin, then increasing the output gain of the plugin while setting the plugin to make no changes to the relative content of the signal. This will increase the overall volume of the recording, which increases the noise floor as well. You may need to gate the signal before gaining to limit the amount of the noise floor which makes it into the final recording. You can also attempt to lower your noise floor, but this is very difficult to make a significant difference without a significant investment into acoustical isolation.

The other option is an external gain booster, such as the Triton Fethead. This is a very simple inline preamp that gives a flat 20 dB boost to your line volume before it hits the preamp. This would give you plenty of headroom to make use of your SM7B, and would be simple enough to use on other mics as well if needed.

You might check out this thread discussing the amount of gain needed for the SM7.

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  • You're not quite getting these specifications right. The microphone's output level actually has nothing to do with "max volume", it just means that the microphone is (at any given level) 59 dB quieter than a microphone with a sensitivity of 1 Vᴏʟᴛ per Pᴀꜱᴄᴀʟ of sound pressure. (1 Pa sound pressure or ~94 dBre20μPa is a reasonably loud sound, but nowhere near the limit of what dynamic microphones can take and less than you get in typical recording situations.) 51.5 dB gain means the EIE Pro's +6 dBV full scale comes down to -45.5 dBV, which the SM7B achieves at 110 dBre20μPa.
    – leftaroundabout
    Oct 1, 2012 at 22:19
  • 110 dBre20µPa may be fine if you're putting the mic up to a cab and blasting it, but to capture something with more dynamic range like vocals, you want to be able to get a decent track volume at 80 or even 60 dB. I wasn't implying that the microphones max volume was dictated by the output level. However, my target gain for recorded tracks is around -12dB on the meters. To get this, my preamp needs around 50 dB of clean makeup gain, which I wouldn't really expect to get from the last 10-15% of a <$300 pre.
    – WLPhoenix
    Oct 1, 2012 at 23:42
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    thanks for the input you guys. Really gained a lot of knowledge from your comments and answers. All puns aside, I was already looking into a preamp anyways to go along with my SM7 as I wanted to start an effects rack and this now seems the perfect thing (/^_^)/. It looks like everyone loves your recommendation of the FetHead so will have to snag one of those too. Money isn't an issue for me right now. But to make sure I'm getting this correctly, I could use the FetHead with a preamp? If I got a more colorful preamp this sounds like a good idea for a more transparent sound.
    – Travis Dtfsu Crum
    Oct 2, 2012 at 13:19
  • The FetHead is essentially a preamp that runs off phantom power that provides a 20 dB boost of fixed gain. It won't work with condensers, but should be fine for any dynamic mics.
    – WLPhoenix
    Oct 2, 2012 at 13:32
  • If I added a phantom power source between the FetHead and a dynamic mic would I work? This is just a question out of curiosity and would probably never do this since my condenser mic is loud enough. Oh and on side note, when videochatting with a group from LA I'm collaborating with, I have been using my SM7B and they said they could hear me and the music played of my monitors loud and clear enough. They were probably biased since it was enough to work but I found this quite interesting... only was really quiet when recording.
    – Travis Dtfsu Crum
    Oct 2, 2012 at 13:45

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