Lowering Backround Noise!!!!

[Raydio]

I have an AKG SolidTube and an Art TubeMP preamp running into my computer running Nuendo and sometimes CEPro2. Im recording in a closet, but I added a few elements to deaden the reverb in the room. For some odd ass reason when I record vocals in the booth I get this electric humming backround sound that sounds like a television interference when you try to watch a channel you don't have. When I raise my recorded vocals the sound shows up and makes the audio sound bad. I can do noise reduction in cool edit, and it disappears... but!!!!!!

Here is my question, since I have Waves Native Bundle and other software Noise Gates, Compressors, and stuff; is it possible of me to add some kind of effect to the track im going to record to before I record, so that I can bypass the backround noise without having to run a Noisegate or Noise Reduction after its recorded??? The Noise Reduction process is so tedious because it takes about a 1 minute to remove the noise from each vocal track. HELLLP!!! LOL.

[Emeric]

You really should trace down the cause of this noise rather than try and fix it with noise reduction before or after it gets to tape.

Does this noise only occur in that closet? Does it occur outside of it? Have you checked the obvious like shitty cables, dimmer switch interference or any type of EMI interference? Do all mic's do this or just the ST? Is it the MP?

I'd remove all these variables first, before considering any type of noise reduction. I record in a rather noisy room, computers, traffic etc, but I know they are there and what the sound is, and how to live and work around it. Find out what is causing this buzz.

[Track Rat]

The Solid Tube is going to have its own power supply and doesn't require phantom power from a mic pre. You're not by some slim chance feeding phatom from the ART to te mic are you?

[c7sus]

Do you have a flourescent light in the closet or anywhere near your rack?

[Raydio]

Well I know its not the cords because i purchased new ones since. There is no florencent lights or phantom power. I have a regular closet with clothes everywhere. Not sure what EMI Interference is, but I noticed that when I turn down the input and/or the output on my preamp, the sound disappears. I can even hear the sound when its not recording; when I have my microphone on, you hear the annoying sound through my speakers. I have Mackie824's so I dont think they could be causing interference. What do you guys think?

[tmix]

R,
It is the tube MP.
I have one that I use all the time for Bass guitar and it is very picky about the relationship (gain staging) between the input gain and output gain. Use your ears. Turn up the input gain about half-way (and while listening through headphones or?)then start turning up your output gain until you start hearing that hum,then back off a little. If this doesn't push the gain stucture to what you like (for tube sound) readjust your in-out relationship. You will always find a sort of sweet spot where you have a near dead quiet relationship until you push it a little further and then you will have the hum.
For what it's worth.

[ambi]

also try turning off your computer monitor, and any other tv or computer monitor anywhere near where you are recording.

Someone mentioned before that they lived near some sort of broadcasting tower of some sort, maybe a radio, or cell phone transmitter, and they picked up the noise in their tube mp.

Im sure its not this case, and most likely what was said about about the mp. I find i get a lot of noise from the TUBE MP as well, but i haven't really used it because of this. I want to replace the tube i think mine maybe befaulty. but i have had it for a year so good luck to me bringing it back.

[Raydio]

Im glad to see Im not the only one suffering. Well its like this... I tried playing with the input and ouput controlls to have it so I dont hear the hum; what happens is I have to compensate for low volume signal on my vocal tracks. I only bought the TubeMP to amplify my signal because without it, virtually no sound comes through to my sequencer. I have two Mackie824's, a Radioshack mixer, and the AKG Power souce thing for my SolidTube mic; all in the same area. Could this cause the hum? Maybe, huh? Let me know if you have any more tips or inexpensive advice. Thanks guys!

[ambi]

try plugging the mic into a seperate outlet?
or maybe the preamp too, or something like that.
i heard someone talking about that in another thread and it seemed to quiet it right up. But it may have been a different situation.

[c7sus]

Actually you want all of your rack gear and computer stuff on the same circuit. This eliminates ground loops in your supply voltage.

Conditioning may help. Also, check your ground on your outlets to make sure it is properly connected. If your outlets aren't grounded that is going to be where you start having problems.

[jugalo180]

it's me again.

originally posted by raydio

I get this electric humming backround sound that sounds like a television interference when you try to watch a channel

i'm 99 percent sure that it is the soundblaster card. i had the same problem. but to check it out just incase i'm wrong. record something, listen for the noise, then keep your mic plugged in but, turn it off this time. press record, check your mixing meter and if you are getting noise registered on your meter and even recorded without your mic being turned on then bam, there is your problem. the outlet (may) be your problem (also), but i'm pretty sure that soundcard is jinxing ya set up duke.

[jugalo180]

originally posted by slackmaster 2000

BigT, the first part of the answer lies in processing.

If you were simply recording one stereo track and not processing it in any way, then recording at 16/44 or 24/96 wouldn't really make much difference.

But that's not what we're talking about. You're going to be doing a serious amount of "math" with the raw data files. The higher the resolution your raw tracks are at the better sound quality you end up with in the end. Consider a graphics artist doing artwork that will end up on the web. Just because the final distributable image will be rendered at 72dpi doesn't mean that the artist started at 72dpi. On the contrary, he/she was probably working with resolutions many times that.

The second part of the answer lies in "headroom."

Digital headroom is not the same as analog headroom, because in the digital realm nothing exists above 0db. However, higher the bit depth, the lower the levels you can record at without sacrificing quality. Remember that the decibel scale is logarithmic, which results in an interesting relationship between resolution and sound level.:

Every 6db of gain requires one more significant bit. Thus, in a 16bit system, -96db to -90db is represented by one bit; -96db to -84db is represented by 2 bits; and so on and so forth until you conclude that -96db to 0db is represented by 16bits, or 65536 (2^16) discrete values. Likewise in a 24bit system -144db to 0db is represented by 24bits, or 16777216 (2^24) values.

That's all pretty obvious, but now think about this. The range -96db to -90db in a 16bit system is represented by *one* bit, which yields two discrete values (1 or 0). Now, try to imagine what a waveform looks like when each sample can only consist of two voltage levels! But of course who cares, right? It's way down at -90db which is pretty hard to hear. Well, let's keep doing the math. The range -90db to -84db is represented by how many discrete values? 2^2 - 2^1 = 2. Again, two discrete values. The range -84db to -78db is represented by 2^3 - 2^2 = 4 values. The range -78db to -72db is represented by 2^4 - 2^3 = 8 values. Let's make a picture:

_____________________ -96db
0000 0000 0000 0000 = 0
0000 0000 0000 0001 = 1
_____________________ -90db
0000 0000 0000 0010 = 2
0000 0000 0000 0011 = 3
_____________________ -84db
0000 0000 0000 0100 = 4
0000 0000 0000 0101 = 5
0000 0000 0000 0110 = 6
0000 0000 0000 0111 = 7
_____________________ -78db
0000 0000 0000 1000 = 8
0000 0000 0000 1001 = 9
0000 0000 0000 1010 = 10
0000 0000 0000 1011 = 11
0000 0000 0000 1100 = 12
0000 0000 0000 1101 = 13
0000 0000 0000 1110 = 14
0000 0000 0000 1111 = 15
______________________ -72db



Continue on, and you soon realize that your prime tracking range of -6db to 0db is represented by 2^16 - 2^15 = 32768 discrete values. Can you now see why people using 16bit systems recommend trying to stay in the yellow? If you track at -12db to -6db, for instance you just halved your resolution, and your waveform is represented by just 16384 discrete levels.

Now a 24bit system looks like the following. Remember that 0db is our hard limit, thus when you increase your dynamic range by increasing the number of bits you use, that range is found at the bottom of the scale:

______________________________ -144db
0000 0000 0000 0000 0000 0000 = 0
0000 0000 0000 0000 0000 0001 = 1
______________________________ -138db
0000 0000 0000 0000 0000 0010 = 2
0000 0000 0000 0000 0000 0011 = 3
______________________________ -132db
0000 0000 0000 0000 0000 0100 = 4
0000 0000 0000 0000 0000 0101 = 5
0000 0000 0000 0000 0000 0110 = 6
0000 0000 0000 0000 0000 0111 = 7

Hmm, looks very similar to the 16bit illustration, except that we've sort of shifted everything way down to -144db. That's true, and at first it might not seem like a big deal, because who cares what happens at -144db? Nobody does. What's actually interesting is what happens up at the TOP!

In a 24bit system, the range 0db to -6db is represented by 2^24 - 2^23 = 8388608 discrete values. Continue on with the boring math, and you'll find that you don't even get into 16bit resolution until you hit -48db (ah, 6db * 8 extra bits = 48db!)!

That means that speaking purely from a resolution standpoint, tracking at -42db to -48db in a 24bit system is equivalent to tracking at -6db to 0db in a 16bit system! Of course our electronics aren't quite that good, and we still have converter self-noise (coming up next) to contend with, thus nobody would actually want to track that low. However, in a 24bit system you don't have to pound the yellow to maintain signal resolution like you do with 16bit....and if you do, you're simply rewarded with exceptionally higher resolution which can result in better math yeilding better end results.

Here's a fun example. Take any 16bit audio file and decrease the volume on it by 90db. This will effectively squash the sucker into just a couple bits. Apply the volume change, reopen the file (if necessary), and turn the volume back up by 90db. "ZZZZZZZZZZgarblegarbleZZZZZZZZZgarble" Well what did you expect? Do the same thing with a 24bit file and what do you end up with? Well, you basically get a 16bit version of your 24bit file...and that ain't so bad

The third part of the answer lies in noise.

Noise is an electronic problem that creeps into our digital world. No converter is going to be perfect, thus way down in lower sound level ranges you're going to have noise. Yick. In the extreme case, take something like an old Soundblaster 16. The noise floor (where the noise level sits) on those suckers was in the range of -40 to -30db! Extremely damaging! In the opposite extreme case, you might find that the noise floor in a very professional 16bit system is down in the -84db to -90db range, which is much more acceptable. But in a properly designed 24bit system, the noise floor can be way down in the -102db to -96db range, thus giving you the FULL 96db of dynamic range that was once promised by 16bit systems, and it can do so at much greater resolution!

Now I should put a disclaimer up. The most important thing about any converter is how it sounds. You want what you hear back out of your recording system to sound as close to what went into it as possible. Converters *damage* incoming sound in a very audible, unwanted way. A cheap card like a soundblaster damages the sound quite severely. A better card like an m-Audio Delta 1010 will still damage the sound in an audible way, but to a much less extent. The point I'm getting at is that it is possible to have 16bit converters that are less damaging than 24bit converters. In fact, I would suspect that a very pricey apogee 16bit converter would sound much better than the converters found in the $600 Delta 1010. Your DSP would sound worse on the 16bit data, but it would probably be worth it to preserve those sources that you've worked painstakenly to capture. The rule of thumb, though, is that 24bit converters really aren't that big of a deal to manufacturers anymore...thus on your better soundcards and converter boxes made today, you're just going to see 24bit converters...that's all there is to it.

Slackmaster 2000

this is where i got it from
http://homerecording.com/bbs/showthr...t=soundblaster

check the rest out if you wish

[ambi]

I had the same problem with my Studio MP. I did a few things that took away most of it.

I think the main thing was i plugged it into a different power socket, and it's now about 10 feet away from my computer and speakers. Also i got a new mic cable, but i doubt that helped.

Give it a shot, you don't loose anything buy plugging it into a different socket.

[Dani Pace]

I had a similar problem, different amps but similar prob. The solution was so simple it's almost funny. I simply had things sitting too cloce to each other and was picking up hum from one amp to another. The transformers set up electrical and magnetic fields that other amps will often pick up. A little rearranging and spreading out got rid of about 98% of my hum, if you have the space, you might want to give this idea a try before spending a bunch of money to solve what might be a simple problem. You might want to check and be sure that everything is grounded really well, even one weak ground can cause hum and make your gear succeptable to outside interference.