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Noise floor issue Single-Channel Preamps
Old 7th September 2011
Here for the gear

Noise floor issue

Hi all,

I'm venturing into voiceover work and set up a modest home studio. While it's not soundproofed, it's very quiet. The only problem at first was that I was picking up the CPU fan from my tower pc, so I switched things up and put Pro Tools 9 on my quad-core Macbook pro instead. Now things are super quiet.

I then plugged my SMB7 dynamic mic into a Focusrite ISA One then out to an Mbox 3. I am using the "Cue mix" feature so I can use the headphones on the ISA One to hear my mix.

The problem is I get really great vocal sound at about 60db, but anything over 50db and I start really hearing the noise floor. If I keep it a 50db everything sounds great but my waveforms are tiny.

I've tried making sure I have clean, grounded power, replacing cables, playing with impedance settings and adjusting the Mbox control panel settings, but unless I keep the gain low (I've read that the SMB7 likes a lot of gain) I just get an unacceptable SNR.

Anyone have any suggestions?
Old 8th September 2011
Here for the gear

Some progress

I've been reading everything I can find on this issue and have tried many things, but this is what has helped the most: disabling all plugins while recording.

I was using the "Podcasting" template in Pro Tools 9 which comes set up with a few tracks for voice overs and some aux sends using buses to route to a master reverb control. As soon as I killed the plugins it helped greatly to reduce the hiss I was getting.

Now I can set the mic in the 60 - 70dB range and it sounds MUCH better. I like to hear a bit of reverb in my headphones when doing vocals, which I can achieve through the Mbox control panel FX Returns without using a plugin, and as an added bonus, it ups my sound input slightly without adding noise. (In fact, if I use the Mbox reverb instead, I can bounce to disk without ever using a reverb plugin at all which seems to save me added noise).

I'm also finding that after I record, I can use EQ to get rid of any excess hiss in the higher frequency ranges. I started down the path of using EQ with a compressor before this, but doing things the way I described earlier, I find I don't need to use a limiter/compressor plugin at all, and can keep my headroom when/if mixing/mastering using these tracks.

If there is a better way or a workflow you use that might benefit me, please let me know.


Last edited by Amplitude; 8th September 2011 at 09:32 PM.. Reason: Typo
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