noise

[dobro]

Why should a C1000 thru an ART Tube MP be quiet, but a Rode thru an ART Tube MP is kinda noisy?

I got closer tonight than heretofore. What I tracked is a keeper, but I've got a question about noise. Don't read any further unless you've got patience and concentration.

I was tracking with three mics - two NT1s and a C1000. One Rode went through an ART Tube MP, and the other Rode went through a VC6Q. The C1000 went through another ART Tube MP.

After the dust had settled, and looking at the waveforms and listening to the individual tracks, I analyzed what had happened. The track with the Rode through the ART was noisier - even before the music started, the center line of the wave form was fatter, and I could hear some hiss. The track with the other Rode through the VC6Q was dead quiet by contrast, and the center line of the waveform was as thin as thin could be. If you've got Cool Edit Pro, you'll know what I'm talking about, and probably other editors are similar. So far, so good - the VC6Q's quieter. But the mystery for me was that the track with the C1000 through the other ART Tube MP was as quiet as the quiet Rode track. Why should a C1000 thru an ART Tube MP be quiet, but a Rode thru an ART Tube MP is kinda noisy?

Or should I stop asking stupid questions and buy another preamp for the vocal Rode?

[drstawl]

Sounds like you're describing unit to unit differences in those Art boxes. And to some, the coloration of the Tube MP is just what they're looking for.
Have you hugged your Meek today?

[bvaleria]

ALL mics have different noise floors... good ones or bad ones... that may be what your hearing...

Bruce

[dobro]

drstal - nope, I'm not talking about coloration, I'm talking about noise. I can hear it in the cans and see it in the waveform.

bvaleria - I understand that, but why would two identical mics display a different noise floor?

[bvaleria]

a-ha!!! Quality Control - or lack of it!!!!

What's his name - oh yeah Bruce Swedien - buys his overhead pairs with sequential serial numbers to ensure more consistency in the capsules. (And he's buying the $5K plus variety...) No wonder there are so many QA issues with mics of considerably less value!...

Bruce

PS - of course, I'm just guessing... there may very well be something wrong with your gear!!!

[Recording Engineer]

"Sounds like you're describing unit to unit differences in those Art boxes."

I agree that is most likely the case. I guess in your case of what you're describing, the greater difference is noise floor rather than tone. Now, who knows where in the circuits the difference is but your best bet is to look towards the tubes first. Yes, matched tubes as well as mics.

"...but why would two identical mics display a different noise floor?"

You mean two of the same model? Because they're not a matched-pair. It's an issue of tolorences and QC.

[dobro]

Okay, speculator, you're on!

I'll stop drinking this wine (well, soon, anyway), go to bed and get a good night's sleep, and when I wake up, I'll swap the Rodes around and try the very same thing I did tonight. If it's just a quality difference between mics, the noise problem should should shift from the vocal track to one of the guitar tracks. If that's the case, then I'll learn something we can all benefit from. Nyaah! If the noise problem doesn't follow the mic in question, then it's something else entirely, right?

Thanks for the input - it made me think of something new.

[bvaleria]

Hey Dobro,

Might be the wine too!!! (Noisier before a coupla glasses, afterwards not as noisy!!!)

Bruce

[Recording Engineer]

Since the sensitivity of the NT-1 and C1000S are different and I don't know if you had the mics at equal distance away from the sound source, I doubt the gain was set the same on the two ART units anyway. THAT would be your difference.

[dobro]

Distance from the mics was irrelevant, since I could see and hear the noise on that one track even before the music started. The gain was the same on the two ART units.

So, am I right in thinking that a Rode through an ART is noisier than a C1000 through an ART? Doesn't make sense to me, but that's the only conclusion I can draw.

Has anyone here noticed that Mic A through this preamp is noisier than the Mic A through a different preamp?

[pglewis]

Only change one variable at a time so you know for sure what made the change. Record 10-15 seconds of silence with the AKG. Then swap only the mic, and record another 10-15 seconds with Rodent number 1 (same pre, same gain settings, same cable, same everything). Then do Rodent number 2. Make sure to have the mics in the same position since room noise might be part of the problem. If one mic is pointed towards the PC fan and another away from it... well, you get the point. Then do the same with the other 2 pre's. It wouldn't take 20 minutes to check all 9 combinations.

[Recording Engineer]

You're wrong about distance from the source being irrelevant.

"...since I could see and hear the noise on that one track even before the music started."

What does that have to do with mic distance?

Which mic was further away and by how much? If the two ART units were at the same input gain, then I'd assume the NT-1 was further away since it has a higher sensitivity than the C1000S. Could the ART outputs be the blame?

Also, how much db difference was there between the tracks?

"So, am I right in thinking that a Rode through an ART is noisier than a C1000 through an ART? Doesn't make sense to me, but that's the only conclusion I can draw."

MMM... I wouldn't draw that conclusion before doing some simple "user tests" and eliminating some possibilities.

"Has anyone here noticed that Mic A through this preamp is noisier than the Mic A through a different preamp?"

OH YEAH... Mics have different noise floors, why wouldn't preamps?

[John Sayers]

Dobro - a friend of mine reckoned that the NT1 was noisier than a CAD plugged into the same pre.

[dobro]

My fuck, I can't believe I haven't noticed this before now. Okay, I tried the comparison test today, but strangely, I couldn't replicate the situation I had a couple of nights ago. The only thing I've determined without a shadow of a doubt is that the Joemeek unit is dead quiet compared to the ART Tube Pres, no matter which mic I run through it. Another thing I've determined without a shadow of a doubt is that I'm dissatisfied with the ARTs now.

So, if I couldn't replicate the problem (all the settings on the gear were the same), then I've got an intermittent problem, and intermittent problems are the toughest ones to track down.

So, how quiet is a Presonus Blue Tube compared to an ART? I have a particular reason for asking...

[El Barto]

Since they use actual tubes, and the amount of time the tubes have been warmed determine the sound in a way...during all tests, did you have the ARTs turned on for the relatively same amount of time?

[Stan Williams]

I would patch both art pres in with no mics, set output to 10, set input to 0 or 10 since you can't rely on settings between, and measure the noise. If one has more noise, swap tubes to see if it follows. If they are the same, i would then try the mics but only through one preamp to see the difference in the mics alone. Thats just what i would do.

[dobro]

Okay, I figured it out, and it wasn't the mics.

I hooked everything up as before and recorded three tracks simulataneously with the three mics. I didn't play or sing anything, I just fiddled with the gain knobs. When the output for the ART pres was at or near max, the noise started, and the waveform reflected it. Cut back on the output gain, and the noise and the waveform wrinkle disappeared. Same with the VC6Q, but not so bad.

So now I'm sacrificing a bit of output gain for the sake of quieter tracks overall. I'm tracking at 24-bit, so it should be okay.