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-55 noise floor Fast Track Pro Condenser Microphones
Old 1 week ago
  #1
Here for the gear
-55 noise floor Fast Track Pro

Hi guys, long time lurker, first time poster

So today I cranked the gain on one of my Fast Track Pro inputs all the way up while the microphone was plugged in, with no phantom power on, the microphone is a condenser so it didn't record anything, and Logic showed an astonoshing -55 in pure noise. Furthermore, the noise doesn't only consist of white noise, but also a very high pitched whine(right word? Not sure. Not a hiss though). My question is; is this what the noise floor really is on my interface or is this not the way to measure it?

The way my system is set-up is as follows:

sE 1440a - FTP - USB to USB C adapter - 2017 MBP. The Fast Track is not connected to an external power source. If it had such a thing with the right specs to safely connect, I would've immediately tried it to troubleshoot. I also don't have any additional XLR in my possession at the moment and I tried this too late in the night to go and buy one.

I've read somewhere that the FTP is not recommended to be connected purely through the USB, but can it cause this sort of a noise floor issue? I am aware that the XLR might be the problem and I'm going to buy a new one tomorrow, but I just need some confirmation that my concern is justified. I also am aware that the FTP is not considered to be the best in its price range and it's also old as hell (i've had this for 8 years) and while I would love to change it, I'm not really comfortable shelling out over £100 for a new piece of gear right now
Old 1 week ago
  #2
Gear Maniac
Quote:
Originally Posted by Jorgensen2050 View Post
My question is; is this what the noise floor really is on my interface or is this not the way to measure it?
That is the noise floor of the system en gain settings of what you had it on.
Noise floor is the measure of the signal created from the sum of all the noise sources and unwanted signals within a measurement system, where noise is defined as any signal other than the one being monitored. (thanks to wiki)
By pushing your gain to max (Pre-amp Gain: greater than 40dB) your signal would be amplified to.
Noise floor is interesting in relation to signal.

p.s. what microphone is that?
Old 1 week ago
  #3
Lives for gear
Quote:
Originally Posted by Jorgensen2050 View Post
.... So today I cranked the gain on one of my Fast Track Pro inputs all the way up while the microphone was plugged in, with no phantom power on, the microphone is a condenser so it didn't record anything, and Logic showed an astonoshing -55 in pure noise. Furthermore, the noise doesn't only consist of white noise, but also a very high pitched whine(right word? Not sure. Not a hiss though). My question is; is this what the noise floor really is on my interface or is this not the way to measure it? ....
Check out the article on my website called "Triple Bypass - Pt3". In there, you'll see some Voxengo SPAN screenshots of a few different preamps with a ~1kHz test signal at 0-gain, 30dB-gain and 42dB-gain.

The change in the white noise floor is attributable to Johnson-Nyquist Noise. That's all an attribute of being in a universe of materials that aren't at absolute zero. The whine that you're hearing is a circuit problem in your interface/preamp.

The rest of the article series should give you some insights, and enough about the experimental setup so you can replicate the testing protocol for your specific hardware.
Old 1 week ago
  #4
Lives for gear
Your “test” doesn’t make sense to me. I doesn’t even tell you the noise floor of your interface with an input at maximum gain. You have a cable and a “dead” mic circuit plugged into the input, which may pick up noise. You don’t have test conditions which guarantee that you are not introducing noise such as RF at the preamp input.
Also, unless you actually use the preamp with the gain wide open, your test doesn’t reveal how the preamp performs at settings you might actually use. Some preamps, particularly some budget preamps, are fairly quiet for most gain settings, but in the last quarter turn of the gain knob the noise jumps up radically.
I would suggest that you shouldn’t be alarmed at your results because your test conditions are flawed.
Old 1 week ago
  #5
Here for the gear
Quote:
Originally Posted by BT64 View Post
That is the noise floor of the system en gain settings of what you had it on.
Noise floor is the measure of the signal created from the sum of all the noise sources and unwanted signals within a measurement system, where noise is defined as any signal other than the one being monitored. (thanks to wiki)
By pushing your gain to max (Pre-amp Gain: greater than 40dB) your signal would be amplified to.
Noise floor is interesting in relation to signal.

p.s. what microphone is that?
It’s an sE4400a, I messed up the name in OP lol
Old 1 week ago
  #6
Here for the gear
Quote:
Originally Posted by MediaGary View Post
Check out the article on my website called "Triple Bypass - Pt3". In there, you'll see some Voxengo SPAN screenshots of a few different preamps with a ~1kHz test signal at 0-gain, 30dB-gain and 42dB-gain.

The change in the white noise floor is attributable to Johnson-Nyquist Noise. That's all an attribute of being in a universe of materials that aren't at absolute zero. The whine that you're hearing is a circuit problem in your interface/preamp.

The rest of the article series should give you some insights, and enough about the experimental setup so you can replicate the testing protocol for your specific hardware.
Thanks, I’ll definitely check that out!
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