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J.S. Gilbert
Talent and/or Voice Producer - Voice Seeker
Joined: 09 Nov 2003
Posts: 629
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 Posted: Mon Feb 19, 2007, 20:17 (GMT) Post subject: Making studios quiet - some thoughts |
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There are a lot of things that can contribute to a high noise floor that is created electronically through the equipment chain and not through actual noise leakage. A simple way to get an idea would be to take your microphone and isolate the heck out of it - put it in a box inside a box, inside a box, etc. and then just turn on your recorder.
Many of the cuases for noise would include:
cheap cabling or other equipment causing Rf interference
issues between balanced (-4db) and unbalanced (-10db) inputs and outputs. Generally XLR connectors are -4db and 1/4" are unbalanced (although not always) -10db is generally considered consumer and -4db is often considerd professional (again not always)
Loud fans inside of computers and inexpensive components in the audio chain can introduce noise. Running background programs in Windows can introduce noise. I have heard that Vista addresses some of these issues, but I'm going to wait a couple of months before I upgrade.
AD/ DA onvertors located inside of the computer as opposed to outside can be nosier. I have heard laptops are genrally nosier than desktop computers.
Flourescent lights are real culprits and often introduce noise. Even the electricity coming into your home could be at fault and introduce noise. Furman and Equi-Tech are 2 companies that sell "Power COnditioners". These are expensive $1,000 - $5,000 and hooking up to one of them will almost always get you about 2 - 7 db better noise floor.
There's a reason why Monster Cable and Mogami cable sell cabling for huge sums of money. Gold plating, hand soldered point to point or really good quality sheilding on a cable costs money. If you are using a mic cable than ran $15 or less, you can probably get a couple db lower by swapping it out for Mogami or other high quality cable. And if your mic is plugged in via 1/4", swapping it for XLR will almost always give you better sound.
Because everybody's setup is different, there's no really great ways to troubleshoot. Try something and if that doesn't work, make sure you can return it. In some cases, especially with lower priced microphones (most are mass assembled in China) quality control can vary widely. I have seen identical microphones from the same manufacturer with widely varying specifications. If possible, bring the mic to where you bought it and ask to A/B test it with another exact same mic from the same manufacturer. Theoretically, if you keep the settings on the pre the same, they should have the same noise floor. You'll be surprised though and mics can vary significantly.
I have heard horror stories and even sat through a few of them at high-end pro studios where they couldn't figure out where the noise was coming from. One studio I worked at had me wait in the middle of a session for over an hour to troubleshoot. I'd peek in every now and again to se the engineers covered with cables, looking like they had just barfed a huge spaghetti dinner. It turned out that their main circuit was shared by the a washer and dryer located next door in a Japanese restaurant.
I have a handmade custom tube mic with power supply that works great here - really low noise. I brought it to a friends studio and tried to do a comparison against his Neumann M149's and he got a low buzz off my microphone. I brought my mic into 3 other studios and no buzz. Tried bringing it back to my friends studio and got a buzz again. Nobody seems to be able to explain this phenomena. Well actually somebody did venture a guess, but it was so over my head that I couldn't tell you what he said.
Hope some of this helps. |
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Colin Campbell
Talent and/or Voice Producer - Voice Seeker
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Joined: 27 Feb 2006
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J.S. Gilbert
Talent and/or Voice Producer - Voice Seeker
Joined: 09 Nov 2003
Posts: 629
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| Posted: Mon Feb 19, 2007, 21:32 (GMT) Post subject: Yes +4db |
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Thanks for catching that Colin. +4db and not -4db. My hands type faster than my brain works.
This site talks a little more about db's the various flavors, meanings, etc. It's pretty boring so I would suggest you invite and engineer friend over, order a pizza and ask them to explain this to you.
http://www.jimprice.com/prosound/db.htm#dBFS |
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Joseph Sinclair
Voice Seeker
Joined: 20 Jan 2008
Posts: 17
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| Posted: Tue Feb 05, 2008, 08:47 (GMT) Post subject: |
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My laptop is much more quiet than my desktop, which surprised me when I tried it. In fact, it seems to be the ideal recording machine. Consequently, I'm using my laptop for my recording setup---quieter and portable. And I edit on my desktop (more comfortable).
I do place the laptop on a 1/8" softcover oversize mouse pad instead of a hard surface, and that mitigates any fan noise. The laptop fan goes on and off as needed. Occasionally I do record the fan coming on in a quiet section. That's just the startup (less than a second), and it can't be heard if it happens when I'm talking.
Obviously, this is just one possible solution to a noise problem, but if one has a portable, it's worth a try. |
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Chris Clementson
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Joined: 14 Jan 2008
Posts: 216
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| Posted: Wed Feb 06, 2008, 09:42 (GMT) Post subject: |
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Sorry to contradict you, J.S., but some clarification is in order:
| Quote: | | issues between balanced (+4db) and unbalanced (-10db) inputs and outputs |
Voltage does not determine whether an audio line is balanced or unbalanced. A balanced audio line has hot, cold and ground, whereas an unbalanced line only has hot and ground. It is perfectly acceptable to have a balanced audio line terminating in a phone plug or a mini plug provided there is a hot, cold and ground connection (ring-tip-sleeve connector). Also, pro and consumer audio are measured in different units. Pro audio is measured in dBu (deciBels unloaded) and consumer audio is measured in dBV (referenced to one volt).
| Quote: | | Running background programs in Windows can introduce noise. |
No it won't. If your CPU starts to labor you may hear additional fan noise (this would be acoustical noise, not electrical) but this could happen even if you are only running your audio application. Background programs can steal CPU cycles when they are needed for real-time recording and this can cause dropped samples, resulting in pops, clicks and stuttering sounds. This especially applies if you're doing networking, which you shouldn't be doing while you're recording audio.
| Quote: | | Furman and Equi-Tech are 2 companies that sell "Power Conditioners". These are expensive $1,000 - $5,000 |
Or you could spend 1/10th that amount and run your gear off an uninterruptable power supply of the type used for computers. They basically consist of a battery and an inverter. The battery acts as a noise filter in essence.
| Quote: | | There's a reason why Monster Cable and Mogami cable sell cabling for huge sums of money. |
Yeah, it's called marketing. I won't go near Mogami cable after a serious RF ingress problem. I use Canare exclusively.
| Quote: | | It turned out that their main circuit was shared by the a washer and dryer located next door in a Japanese restaurant. |
It's always something. I once rented a (lousy) recording studio in Las Vegas and I had to ask the guys to please turn off the refrigerator because the compressor noise could be heard rather plainly in their (not-so-)soundproof studio.
I still have my cheap Chinese condenser mic. When I first bought it there was indeed a pronounced hum/buzz. The hum/buzz got worse when I moved the mic near an AC power strip or lighting dimmer. I correctly deduced that it was a shielding problem. It turns out that they used electrically non-conductive paint to finish the mic and when the two halves of the mic case were screwed together, there was no contact to ground for the upper part of the case and thus no shielding. I took a piece of fine grit sandpaper and sanded the paint off the rim of the lower half of the case so that there would be electrical continuity to the upper half. Voila! I can now hold it near light dimmers, AC power strips or anything else and there is no hum or buzz. Sometimes a little ingenuity and 5 cents worth of sandpaper go a long way  |
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Allen Brown
Talent and/or Voice Producer - Voice Seeker
Joined: 22 Aug 2005
Posts: 520
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| Posted: Thu Feb 07, 2008, 20:27 (GMT) Post subject: |
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| Chris Clementson wrote: |
| Quote: | | Running background programs in Windows can introduce noise. |
No it won't. If your CPU starts to labor you may hear additional fan noise (this would be acoustical noise, not electrical) but this could happen even if you are only running your audio application. Background programs can steal CPU cycles when they are needed for real-time recording and this can cause dropped samples, resulting in pops, clicks and stuttering sounds. This especially applies if you're doing networking, which you shouldn't be doing while you're recording audio. |
Pops, clicks...uh, isn't that noise? Isn't that what JS was saying?
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Chris Clementson
Voice Seeker
Joined: 14 Jan 2008
Posts: 216
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| Posted: Thu Feb 07, 2008, 22:17 (GMT) Post subject: |
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| Pops and clicks are due to intermittent dropped samples. It is not continuous background noise such as a hum, buzz or static. |
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Erik Sheppard
Talent and/or Voice Producer
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Joined: 02 Mar 2005
Posts: 1317
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| Posted: Thu Feb 07, 2008, 22:30 (GMT) Post subject: |
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Thanks for your input Chris.
Jeez, I know people like to argue with JS, but who brings up a year old thread to disagree? I cannot think of anything I would disagree with JS on in this thread.
To further fan the flames (I am a terrible Mod) I have also heard, and experienced, clicks from background programs running. Apparently LAN connectivity can cause this as well, presumably for the same reasons.
Because of a myriad of potential problems, I think it goes without saying that a professional talent should have a dedicated recording computer with tons of RAM, only the programs you need installed and no internet connectivity. Why invite problems?
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Joe Rodriguez
Talent and/or Voice Producer - Voice Seeker
Joined: 07 May 2006
Posts: 156
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| Posted: Fri Feb 08, 2008, 19:26 (GMT) Post subject: |
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| Chris Clementson wrote: | | I still have my cheap Chinese condenser mic. When I first bought it there was indeed a pronounced hum/buzz. The hum/buzz got worse when I moved the mic near an AC power strip or lighting dimmer. I correctly deduced that it was a shielding problem. It turns out that they used electrically non-conductive paint to finish the mic and when the two halves of the mic case were screwed together, there was no contact to ground for the upper part of the case and thus no shielding. I took a piece of fine grit sandpaper and sanded the paint off the rim of the lower half of the case so that there would be electrical continuity to the upper half. Voila! I can now hold it near light dimmers, AC power strips or anything else and there is no hum or buzz. Sometimes a little ingenuity and 5 cents worth of sandpaper go a long way |
Jeez, how'd you figure that one out. Which cheap chinese condenser are you using by the way.
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Joe Rodriguez
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Chris Clementson
Voice Seeker
Joined: 14 Jan 2008
Posts: 216
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| Posted: Sat Feb 09, 2008, 05:45 (GMT) Post subject: |
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| Quote: | | who brings up a year old thread to disagree? |
Well, I wasn't around a year ago
| Quote: | | I have also heard, and experienced, clicks from background programs running. Apparently LAN connectivity can cause this as well, presumably for the same reasons. |
Those are the dropped samples mentioned above. The CPU isn't available to service your real-time audio because it's off somewhere doing something else.
| Quote: | | Jeez, how'd you figure that one out. Which cheap chinese condenser are you using by the way. |
MXL 990s. They were originally acquired for the Mic Listening Room and can be heard there. Supposedly you can hotrod them by replacing three capacitors but you have to be handy with a soldering iron. I haven't done mine yet.
After 37 years in television I've learned a thing or two  |
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Gregory Houser
Talent and/or Voice Producer
Joined: 15 May 2005
Posts: 177
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| Posted: Sun Feb 10, 2008, 17:55 (GMT) Post subject: |
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| Chris Clementson wrote: |
Those are the dropped samples mentioned above. The CPU isn't available to service your real-time audio because it's off somewhere doing something else.
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Not always. It could be dropped data caused by an overloaded front side bus, improper RAM management, a bad RAM stick, a BIOS malfunction, RF interference caused by certain models of HDD (Maxtor is not used in several industries for this reason), I've even found dropped samples caused by inefficient driver design on certain motherboards (MSI and Tyan immediately spring to mind).
CPU and RAM are good first places to look, but there's a lot of places for this stuff to hide. But you're absolutely correct in the statement that it would cause dropped signals (with minor exceptions). |
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Chris Clementson
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Joined: 14 Jan 2008
Posts: 216
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| Posted: Mon Feb 11, 2008, 02:55 (GMT) Post subject: |
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| Quote: | | Not always. It could be dropped data caused by an overloaded front side bus, improper RAM management, a bad RAM stick, a BIOS malfunction, RF interference caused by certain models of HDD (Maxtor is not used in several industries for this reason), I've even found dropped samples caused by inefficient driver design on certain motherboards (MSI and Tyan immediately spring to mind). |
Those things can all cause dropped audio samples, yes, but they would also cause maladies which would affect the rest of the system in addition to audio, e.g. graphics, networking, disk I/O, etc. Absent any of the above, audio samples can still be dropped because the computer is simply doing what it was designed to do: preemptive multitasking. |
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Gregory Houser
Talent and/or Voice Producer
Joined: 15 May 2005
Posts: 177
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| Posted: Mon Feb 11, 2008, 05:15 (GMT) Post subject: |
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| Chris Clementson wrote: |
Those things can all cause dropped audio samples, yes, but they would also cause maladies which would affect the rest of the system in addition to audio, e.g. graphics, networking, disk I/O, etc. Absent any of the above, audio samples can still be dropped because the computer is simply doing what it was designed to do: preemptive multitasking. |
Depends, but again not always.
It's rare that I've run into graphics or networking issues when a chipset wasn't compatible with the drivers for PT-HD for example or some of Mackie's products. Same with several of the HDD issues I've been finding as of late (BTW: folks, feel free to scan your HDDs when you initially get and install them... might save you down the road).
Personal opinion is with you that it's best to look at the big stuff. Afterwards, work your way down. Even a bad IDE/SATA cable can cause dropped audio while tracking (and man those are a real bugger to track down). |
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Chris Clementson
Voice Seeker
Joined: 14 Jan 2008
Posts: 216
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| Posted: Mon Feb 11, 2008, 05:44 (GMT) Post subject: |
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| Quote: | | It's rare that I've run into graphics or networking issues when a chipset wasn't compatible with the drivers for PT-HD for example or some of Mackie's products. |
Well yeah, if your hardware is incompatible with your audio drivers then you're going to have audio problems (how's that for circular reasoning? ).
If you have a bum memory stick or a bad BIOS something-or-other then it could affect any part of your machine. |
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Gregory Houser
Talent and/or Voice Producer
Joined: 15 May 2005
Posts: 177
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| Posted: Mon Feb 11, 2008, 20:42 (GMT) Post subject: |
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| Chris Clementson wrote: |
Well yeah, if your hardware is incompatible with your audio drivers then you're going to have audio problems (how's that for circular reasoning? ).
If you have a bum memory stick or a bad BIOS something-or-other then it could affect any part of your machine. |
With Digidesign, anything is possible... it's usually an incompatibility with some of the HW in the PCI cards that I get a call for.
The wierdest thing was one app which, for some reason unknown to myself or most of the company which developed the product, send out a ping of death to other local systems on your home network. Scary thing was that it was intentionally coded into the application. That's some nice QA checking on the code there Lou
Bum memory stick or bad BIOS can affect anything, but if you check some of the coding for some stuff (see aforementioned companies), some of the stuff they get these developers to do is just plain wacky.
//I'm still trying to figure out some of the decision-making processes behind the FW drivers for Mackie's ONYX series of mixers. |
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