White Noise

[greghouston]

This is my first post here.

I am using a Focusrite Saffire 6 USB audio interface, Shure SM57, Cubase 5, and Windows 7 64 bit.

My Focusrite USB ASIO Drivers are set at 44100 kHz 24bit . I have the Focusrite USB Driver v1.9 installed.

In Cubase, with my input set to 0 db, my vocal track set to 0db, and the master output set to 0db, and nothing plugged into the input XLR on the Saffire 6, I can set the gain of that input at about 7.5 before white noise starts becoming apparent. At 10 the white noise is incredibly apparent.

Now plugging in my Shure SM57 microphone with the gain set at 7.5 on the Saffire 6, once I record my vocals, they play back at -18 to -25db (depending on how loud I am singing) with no white noise. This is 18 to 25 db too low though, and is without any VSTs applied yet.

As soon as I add even a gentle compressor to my vocals, white noise becomes apparent. Once I add some saturation and a maximizer, getting my overall sound closer to 0db, white noise is very much apparent.

My question is, what options (minus using a gate) do I have to get my vocal volume near 0db without the white noise?

Different USB audio interface?

Different microphone?

Other options that as an amateur might not occur to me?

Much appreciation for any help.

 

[greghouston]

I just tested to see what my noise level is with my VSTs on that I am using, with the Saffire 6 set to 7.5 gain, and no mic plugged in. The noise level is -56 db. I would probably be happy with anything under -85 db.

Note that my trying to get 0db volume might be high, but even if I were aiming for -6 db, I would still have -62 db of noise.

I'm not sure if I could compensate somehow if my mic were putting out more power. My Shure SM57 doesn't have a lot of output power. Even though the Saffire 6 has built-in mic pre-amps, could I add a pre-amp between my mic and the Saffire 6? Any thoughts on whether or not this might help?

I'm guessing a condenser mic might help, and would probably purchase one ($300-$350) if I knew it would solve the issue, sound good with my voice, and not pick up too much ambient noise. Being that I live in a small town though, there is no place where I can audition condenser mics.

For a final recording, what is a good peak db to shoot for? I've just been assuming it needs to be around 0db in order to be as loud as other media.

 

[greghouston]

Saffire 6 USB noise:
EIN > 120dB (measured with 50dB of gain with 150 Ohm termination (20Hz/22kHz bandpass filter)

It looks like the Lexicon I-ONIX U22 may have a better noise rating, but I don't know enough about these ratings to know if it would make a significant difference for me:
-125 dBu @ 58dB gain typical (150Ω source) -129 dBu @ 58dB gain typical A-weighted (150Ω source)

The Lexicon seems to have 8 db more max gain than the Saffire, while having 5db less noise at that max gain ... If I understand the figures correctly. The specs for the Lexicon actually state that it's max gain is 58 db, whereas I don't see a similar stat in the Saffire specs, so I am not sure if 50 db is it's max gain or not.

 

[witzendoz]

Read this thread about digital ground noise, that is where you problem is, it is mostly with lap toips but you do have problems with desktops also.

Alan

 

[greghouston]

Thanks Alan. After reading that thread, and I may have not understood it correctly, I tried a few things hoping that I could discern for certain that it is a ground loop issue.

1. I removed my studio monitors from the equation entirely, unplugging them from the audio interface and the wall outlet. No change.
2. I unplugged all unnecessary equipment, and basically just had my computer and monitor plugged into my battery backup which in turn is plugged into the wall. I also removed all usb connections other than my mouse. No change.
3. I tried plugging my computer and monitor directly into the wall outlet bypassing the battery backup. No change.
4. I plugged my monitor and computer back into the battery backup, but did not plug the battery backup into the wall, so the monitor and computer, as well as the usb audio interface were all running off of battery backup. No change. Shouldn't this rule out most potential ground loops?

Is it still possible this is a ground issue?

I was really hoping running off the battery backup would solve the problem so I could just get an isolation transformer and be done with it.

Something I should also note, I live in a really old house, and do not believe that my outlets are grounded. I know it's not safe, and am planning on getting it fixed soon.

 

[greghouston]

Just some other notes that may or may not be helpful for troubleshooting...

The audio interface does not make any white noise when playing anything that was not recorded with it. So iTunes sounds fine being played through the audio interface, soft synths in Cubase don't generate any white noise when played through the interface. All the noise is coming from the xlr input on the interface, and even if nothing is plugged into it. With further testing I found I had to have the gain knob at slightly below 4 (it goes up to 10) for the noise to fall below -86 db, and that is with no vsts turned on and the input and output in Cubase set to 0 db.

Also, the only card installed in my computer is the video card. The only other extra components are a couple dvd player/recorders.

 

[jaygee]

I personally record individual tracks at -6 db peak.

Sounds like you're getting white noise from the preamps, have you tried a condenser mic ?
They require a lot less gain than a dynamic like a sm57 and would allow you preamps to
operate at a lower level to help eliminate the white noise.

Another method is to record the tracks at a lower level via the preamp and them apply
digital gain inside the daw to bring up the levels.

 

[mjbphotos]

Yes, sounds like it is the mic pre-amps that are your problem. Is this a new interface? If so, take it back and exchange it or another one.

 

[greghouston]

I personally record individual tracks at -6 db peak.

Yeah, most of my individual tracks are well below even -6 db peak. It's when I get to the master bus that I add the maximizer which gives a little boost too everything and then limits the peaks at 0 db.

Sounds like you're getting white noise from the preamps[...]

[...]have you tried a condenser mic ?

I ordered a rode NT1-A last night.

 

[greghouston]

Yes, sounds like it is the mic pre-amps that are your problem. Is this a new interface? If so, take it back and exchange it or another one.

Thanks, yeah that's a bummer. I purchased it September 28th, 2010, so less than a year ago. The issue has existed since I purchased it, but being new to these things it didn't start to occur to me that the noise shouldn't be so high until recently. I've just been using a gate to minimize it, which is no longer acceptable to me. I can't find on the Focusrite or Musician's Friend website what sort of warranty the Saffire 6 has, but I did email their technical support about the issue.

 

[jaygee]

Very quiet mic. You should really notice an improvement in the noise levels.

 

[greghouston]

The RODE NT1-A made a massive difference. I've got the 10db pad turned on the Saffire 6 XLR input, with the gain set to 2 (probably going to try 3), but now, rather than getting tremendous white noise I get a small bit of room noise, primarily from my computer. I've been working on making my computer quieter (installing quieter fans, turning on the variable fan controls in bios, and applying wall treatment behind the computer), but I'm probably going to end up having to just put it in another room entirely. Of note, I am also using an Auralex MudGuard.

It's also going to take some time to get adjusted to the sound of the new mic. The lows on the SM57 were always too boomy for my voice, and the mid-highs were harsh. The RODE NT1-A has a much flatter, softer, lusher sound, more like something I'd expect a low budget version of Lenny Kravitz to use.

A version of the RODE NT1-A with a much tighter cardoid pattern would be incredible.