Assistance with hiss diagnosis

[kozikowski]

There are two other considerations: Building a complex analog device isn't easy and each part has a tolerance. I built a big, take-no-prisoners microphone preamplifier and I hand-selected some of the parts because about half of the ones I got from the supplier may have been in tolerance, but either had wimpy amplification or were too noisy for the job.

That and it's possible the mic is broken. Neither of those is likely, but then having one of these fail like yours isn't likely either.

Koz

[kwartz]

I've been playing with the input volume in Audacity, along with changing the level on the mic itself. It seems like if I turn up the input volume any higher than 0.03 - 0.05, I start to get the hiss. This is even with the mic volume turned pretty low. The best levels I seem to get are with the mic volume at about 3/4 and the input volume at 0.03. But this leaves it pretty quiet, running about -20db - -18db. If I use Amplify, then the hiss is noticeable again.

I have two examples, one from the mic about 3/4: https://www.dropbox.com/s/i4n3ias56175l ... r.wav?dl=0

One from the mic a little above 3/4: https://www.dropbox.com/s/e3my7b04yxwc1 ... s.wav?dl=0

Thanks again everyone.

[Trebor]

I've been playing with the input volume in Audacity, along with changing the level on the mic itself. It seems like if I turn up the input volume any higher than 0.03 - 0.05, I start to get the hiss. This is even with the mic volume turned pretty low. The best levels I seem to get are with the mic volume at about 3/4 and the input volume at 0.03. But this leaves it pretty quiet, running about -20db - -18db. If I use Amplify, then the hiss is noticeable again.

From that experiment there isn't a "sweet spot" where the hiss is lower :¬(

From those WAV files I just noticed your hiss noise is quantized , (only discrete amplitude values are permitted) ...

Your hiss noise is quantized.png (62.98 KiB) Viewed 2162 times

The self-noise of a microphone isn't like that : self-noise is thermal noise which isn't quantized.

Some digital miss-match of bit-depth or sampling-rate between Audacity and the mic may explain your quantized hiss noise. Double check you have these settings in Audacity ...

Samson G-Track ... Set the computer control panels, preferences and Audacity drop-downs to recognize the Samson G-Track USB device for both recording and playback. The G-Track's USB name is USB Audio CODEC
Set Audacity Preferences:

Click on Edit > Preferences (on a Mac this is Audacity > Preferences)

in the Quality tab:
set Default Sample Rate to 44100 Hz
set Default Sample Format to 32-bit float
in the Devices tab:
Under Playback set Device to the microphone USB Audio CODEC
Under Recording set Device to the microphone USB Audio CODEC

http://wiki.audacityteam.org/wiki/Overd ... Microphone

Bold emphasis is mine : of the preference options available a bit-depth miss-match seems like the prime-suspect to me.

[kwartz]

I checked those settings, and they all match what you listed.

Reading up on quantized hiss noise now... looking on the bright side of things, this is giving me the impetus to learn a lot.

Thanks again for your continued assistance, it's much appreciated.

[Trebor]

I checked those settings, and they all match what you listed.

The only remaining thing I can think of is an audio-driver [conflict?] problem ...
http://forum.cakewalk.com/FindPost/1530985

If it is a due to audio-drivers, the quantized hiss problem will not be specific to Audacity,
e.g. will also occur on Windows built-in sound recorder.

[kwartz]

I'm traveling this weekend and won't have access to the laptop and mic until I return, so I'll run through this when I get back.

Thanks for the info.

[kwartz]

I tested recording using the Windows Sound Recorder. Here are links, wasn't sure if it was best to leave it as the normal WMA the sound recorder generates, or to convert it.

WMA - https://www.dropbox.com/s/beb4ieq95gdme ... d.wma?dl=0

WAV - https://www.dropbox.com/s/sypvsyzmb1ddi ... d.wav?dl=0

This was with the mic level at 50%. It sounds to me like the hiss is still there, but I haven't been able to figure out if it's quanitized...

If it is, from what you said earlier Trebor it points to a driver problem. I'm using the USB Audio CODEC, which, if I understand that page you linked, is what I should be doing because it's the default and not anything provided by Samson. But chances are high I'm misunderstanding something here...

Thanks again.

[Trebor]

I tested recording using the Windows Sound Recorder. Here are links ...
WMA - https://www.dropbox.com/s/beb4ieq95gdme ... d.wma?dl=0
This was with the mic level at 50%. It sounds to me like the hiss is still there, but I haven't been able to figure out if it's quanitized...

The hiss noise on that wma file doesn't have the quantized appearance, ( it does sound loud though for a $100 mic ).

A minority of "Samson G-Track USB Condenser Microphone" buyers report a hiss-buzz, e.g. ... http://www.amazon.com/gp/review/RXYYAR4 ... B0015MJE22

and claim it's a driver problem, ( e.g. a particular mic works OK on some computers, not on others ) ...
http://www.amazon.com/review/RKG9IWVLE6 ... B0015MJE22

[kwartz]

Thanks for looking up that info. I haven't noticed much change between the various computers I've tried it on. Normally use it on a Windows 7, which is what that poster says works well. But I've also tried it on another 7 machine (both are SP1), an XP SP2, and MAC OS 10, with not much difference. Maybe I just have a bad mic. Bummer that I bought it five years ago and only now thought to myself, "Hey, maybe I should try to track down the source of that hiss so that I don't have to mess with the Noise Reduction".

Guess I'll be working through any tutorial info there is on the Noise Reduction, to make sure I'm really using it correctly.

Thanks again.

[Black Dog Bluez]

Been there -- USB mics are not a good idea/they pick up all kinds of computer noise/computers were not designed for recording high quality, whether mic jack or USB route. It's possible newer mics are better, and of course more expensive ones--BUT if you have money to spend, go with stand-alone stuff designed for recording music. For about a hundred you can get a Tascam portable music recorder. Then upload to the computer for editing/mastering, sharing/selling and becoming world famous. Cheapest highest quality route, IMO. I get better quality recording with my iPod (until I can get better equipment) then I did with a USB mic. https://soundcloud.com/ronphilip