Background noise

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Jubal
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I am just getting started with Ardour, and I am liking it so far.

The trouble I'm having is with background noise. No matter what I try, I always get a slight hiss behind anything I record. Is it possible to make recordings without this? Is there a plugin I can use within Ardour to eliminate the noise?

At first I thought it might be my computer making noise, but even when I move the microphone away there is still that hiss. Could it perhaps be the microphone?

Thanks so much for your help! I hope my question isn't too elementary :-)

philip8888
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Do not know about a plugin for that, and there may be one.

But this link here is a great tool to help you set your studio up to minimize these problems.

http://www.tweakheadz.com/guide.htm

hogiewan
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a lot of things in your setup may introduce the hiss.

peder
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You might want to open the harddrive and clean it. Perhaps you've got some dirt on the reading head. ;)

Seriously though; you need to describe your setup (soundcard, mixer, mic, way of recording et.al.) if we're gonna have a chance to help you.

I sometimes get a lowfrequent hum in my recordings, due to a ground loop I haven't bothered taking care of, but I can't think of anything specific that would cause hiss.

You can try to do a "silent" recording, disconnecting everything from the soundcard input, to see if you still get hiss. If not, start connecting things one at a time to see when the hiss is introduced.
If the silent recording has hiss you got a bad soundcard or some misconfiguration in the alsa/jack/ardour chain.

hippie
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Could be JACK as well.
May want to fiddle with the periods/buffer settings. I know for myself, the default settings produced a loud static and buzz behind my tracks. I had to change the Periods/Buffer to 4 and increase the Frames/Periods to 512.

Reuben
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A "hiss" sound generally comes from microphone preamps. The crappier the preamp, the louder the hiss. This is referred to as the "noise floor". Many times preamps will list a signal-to-noise-ratio in the technical specs in order to give an idea of how good they are. Read here for more info: http://en.wikipedia.org/wiki/Signal-to-noise_ratio

Generally you can minimize this by recording closer to your source so that you don't have to push the gain as high. Also if you use a compressor with a gain stage, that will also reduce your dynamic range, and hence reduce your signal-to-noise-ratio. (i.e. more hiss) Also condenser mics can help, because they are naturally much more sensitive, so you don't have to give them as much gain.

Ultimately, the best way to deal with it is to just buy a nice preamp. The cleanest preamp with the lowest noise floor I've ever personally used is the TRUE Systems Precision 8. http://www.true-systems.com/products_P8.html

hippie
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Speaking of recording gear... make sure you're using balanced mic cables too (and not any cheap unbalanced radio shack cables) to reduce line noise. Mogami cables will be your best friend. Expensive, but worth every dollar and comes with lifetime warranty.

hogiewan
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doesn't matter if the cables are Radio Shack or not, balanced is balanced, and any noise that is created in the cable will cancel out (yes I know cheap cable can effect the sound in other ways, but not added noise)

Reuben
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There is a difference in cable where the ground lead doesn't shield the other two leads. Some cable just has the ground running in parallel with the other two leads instead of webbed around them as a shield. The shield type will do a much better job at eliminating RF interference. (This does produce a cleaner signal over exceptionally long runs, but has nothing to do with the "hiss" problem that started this thread)

hogiewan
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The webbed ground helps to keep interference from inducing a signal into the audio leads. However, since the two audio signals are out of phase and any induced signal would in phase, all induced signal is canceled out at the balanced receiver.

I'm just saying all this because you introduced the idea of expensive cables as a possible fix to the noise problem that started this thread. I just want people to know that there is no need to drop cash on new cables if you are already using balanced cables, no matter their quality.

The better/more-expensive cables are worth the extra cost because of the resistance/impedance benefits, not noise reduction. There is a lot of misinformation in the realm of audio cables, especially on the internet, and I don't think that the ardour forum is a place to add more.

thorgal
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without more h/w info from the original author of this thread, it's hard to say. The thing that comes to mind is : onboard sound chip in a laptop. Whatever mic you use, this is probably one of the crappiest sound system you can use. If this is indeed the h/w config of the guy, no need to look further I would say.

hippie
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"I’m just saying all this because you introduced the idea of expensive cables as a possible fix to the noise problem that started this thread."

That was me.. my bad!

The better/more-expensive cables are worth the extra cost because of the resistance/impedance benefits, not noise reduction.

Not sure if this is a good example of what you're talking about, but figured I'd throw this out there. I bought 2 balanced cables from radio shack to plug up 2 condenser mics on my drumset. After getting really frustrated (thinking it was something wrong with Acid Pro or my 1010 breakout box/phantom power), it turned out that the cables were the problem. I ended up putting two Mogami cables on the condenser mics and using the "El Cheapos" on two other mics that didn't require phantom power... and I was off to the races.

Moral of the story.....
While Radio Shack balanced cables may not introduce "noise," they still suck. Suck it up and buy expensive Mogami cables!! =)

muzicman0
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so...what was the 'problem' with the radio shack cables? what problem did they cause?

It never ceases to amaze me when I go to best buy and the sales force tries to sell me monster cables, because they will improve the sound...yeah, right...we're talking line level, not speaker level...

mm0

hippie
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I know absolutely nothing about cables/audio/science of it all. But my absolute best guess was the fact that when I enabled "12v Phantom Power" to the line, it produced so much garbage that it effectively became useless. Using the cable on any other mic (that doesn't require phantom power) worked just fine. So... perhaps it is "shielding" or just the overall construction? Really, I have no idea. I just know using a balanced Mogami fixed it!

Monster Cable is name-brand whore for sure. Charging $60- 120 for an HDMI cable, or Component Cables is absurd. Online stores like Mwave and NewEgg sell em for like $10 and they work just fine. But I'm convinced now that cheap mic cables, balanced or unbalanced, do pose serious issues with recording. Perhaps the high cost for Monster mic cables is worth the price?

I paid $46 per Mogami cable and they come with a lifetime guarantee. Monster cables are about $12 cheaper than Mogami, but only come with like a 25-year guarantee. The Radio Shack cables were $25 ea. can only be returned within 30 days of purchase, and only work given certain scenarios. Choice is yours... I suppose.

muzicman0
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no, I mean, what was the symptom...was it excessive noise, just didn't work, etc...

peder
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Hmmm, wonder what happened to Jubal and his original problems (before we ventured off into cable-land)?

hogiewan
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What kind of condenser mics do you have. Most of them like 48v instead of 12.

Jubal
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Thanks for all the comments and suggestions. I just hadn't checked the forum in a while; I thought it would let me know if someone replied.

Anyway, I believe the noise was being caused by my mixing board, as a result of me not knowing how to adjust it. I have been able to minimize the noise substantially by turning the trim up nearly all the way, and adjusting the level a bit. So the noise is still there, just very faintly, but I am much happier with the result I'm getting.

Another quick question--maybe I won't have to start a new thread--I'm getting some popping sounds periodically in my recordings, and I'm thinking it may be because I don't have JACK adjusted right. Does anyone have any suggestions for this?

Thanks!

peder
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You are probably getting xruns in jack, they sound like pops or clicks in the recording. Try increasing the Frames/Period rate in qjackctl or the -n flag in jackd.
If you have a realtime kernel properly set up 64 or 128 should be possible. If not you should start at say 2048 and work your way down to see the lowest value you can safely use.