Is noise reduction always required?

  • Thread starter Thread starter aeg0
  • Start date Start date
A

aeg0

New member
Hi Everyone. I'm running a basic home setup:

AT2021 / AT4040 through a Tube MP
Tascam US122 mkii
Mbox2
Adobe Audition 3
Windows Vista x64

I find that all my recordings end up having a lot of background noise. I tried using Audition's inbuilt noise reduction plugin, but that sometimes reduces the clarity of the actual audio file - I'm recording a lot of acoustic guitar mainly, so I need the crisp highs. I hear other home recordings, and they seem to have no noise at all. Do they always run a noise reduction on their recordings? What about professional/semi-pro studios? Is noise reudction ever used in there? The AT4040 is supposed to be a decent mic, and a lot of people recommend it.

I guess what I'm trying to ask is - Is noise reduction a normal step in the recording process, or just a problem with my setup?
 
Noise reduction is usually only used as a "last resort" process. Find out where the noise is coming from and get it gone before the "RECORD" button is ever pressed.
 
What Massive Master said.

Noise reduction is a last resort, emergency tool that should almost never be used unless your speciality is audio restoration or something.

Your gear is good stuff and should be capable of producing recording with an impressively low noise floor. You should find out what's causing the noise and eliminate it at source.

If you have irreplaceable material which can't be re-recorded, a hint for using the Audition noise reduction (which is one of the best there is--people have won awards for restoration work on old records using Audition) you can generally do better by using several passes of very light reduction rather than one big one. Also, playing with the FFT size can help a lot.

Bob
 
In the many years I'e been recording I don't believe I've ever had to use any noise reduction. Now I've used it to clean up vinyl and cassettes but that's about it. As stated above, try to find the source of your noise and fix that.
 
Thank you all for the helpful replies.

Do external pre-amps such as the ART Tube MP add any noise to the recordings? I'm stuck in a situation where my levels are really low (Mic/Acoustic Pickup > Tascam USB interface), which requires the Tube MP to add some gain. My guess is that this will add some noise, but I cant seem to get a decent level without it.

Also, will using a shorter XLR/line cable help?
 
I suppose in theory an external pre amp could add a bit of noise but, barring a fault, the amount should be so low as to be un-noticeable.

Mic level signals on a balanced XLR cable should be good for hundreds of meters without noise--and even when you start to get some, it's usually some form of electrical noise, not just general background hiss.

Line live balanced signals are even more robust--I've seen them fed quite literally for miles with no noise.

A few suggestions:

First, maybe grab us a sample of the noise problem you have and post it here on the forum. Not always, but sometimes the character of the noise can suggest where it's coming from.

Second, as far as possible the best way to chase noise issues is to change elements of your system one bit at a time. Plug in a different mic, swap cables, leave out the mic pre, etc. If you come to one thing that eliminates the noise, you've found the culprit.

Finally, your comment about not having enough gain without an extra pre amp has me slightly worried. The Tascam should have adequate gain for the mics you mention. I wonder if there's some issue with positioning, gain staging or whatever.

Bob
 
aeg0 said:
Hi Everyone. I'm running a basic home setup:

AT2021 / AT4040 through a Tube MP
Tascam US122 mkii
Mbox2
Adobe Audition 3
Windows Vista x64

I find that all my recordings end up having a lot of background noise. I tried using Audition's inbuilt noise reduction plugin, but that sometimes reduces the clarity of the actual audio file - I'm recording a lot of acoustic guitar mainly, so I need the crisp highs. I hear other home recordings, and they seem to have no noise at all. Do they always run a noise reduction on their recordings? What about professional/semi-pro studios? Is noise reudction ever used in there? The AT4040 is supposed to be a decent mic, and a lot of people recommend it.

I guess what I'm trying to ask is - Is noise reduction a normal step in the recording process, or just a problem with my setup?
Click to expand...

aeg0,

The answer is "no," noise reduction should not be a normal step in the process, especially if you have a decent LDC mic in the AT 4040. If you're getting lots of noise, you've got something going on between the mic and the computer than needs to be solved. I'm guessing your problem is with hum or hiss or both. The first thing to do is check levels and gear condition at every stage. So first, check to see if the mic has any loose screws or anything like that. Then check to see if the cable connections are tight with no loose bits causing trouble.

The most likely thing, though, is your interface and/or computer. I didn't see mention of an interface. What are you using for that? You can get good, quiet ones for starting at around $100, possibly a bit cheaper. If you already have a decent interface, check your cabling. Mixing balanced and unbalanced cables and gear can cause all manner of noisiness. If it isn't the balance, you might check to see if your audio cables are too close to any power supplies or power cables, and separate them. Finally, if your interface is a USB type, try a different USB port to see if that helps.

It is much better to prevent as much noise as possible than to try to get rid of it after you record it. Using Noise Reduction should not be the norm.

Something in the above ought to help.

Good luck!

Ken Theriot
 
Everything adds noise.

Noise reduction software is the last resort - I've never used it as it tends to have a negative impact on the rest of the signal...
 
Bobbsy said:
First, maybe grab us a sample of the noise problem you have and post it here on the forum. Not always, but sometimes the character of the noise can suggest where it's coming from.

Finally, your comment about not having enough gain without an extra pre amp has me slightly worried. The Tascam should have adequate gain for the mics you mention. I wonder if there's some issue with positioning, gain staging or whatever.
Click to expand...

I've uploaded a few samples on Soundcloud. Please ignore the timing and the guitar tuning.

The first recording is directly through the Mbox2. So I used the AT2021 SDC > Mbox2 > Asio4All > Adobe Audition 3. The level on the Mbox2 was at about 70%, and then I amped it by 15 db.

soundcloud.com/aeg0/at2021-guitar

The second one, AT20201 > Tube MP > Tascam US122 > Asio4All > Audition 3

The input level on the Tube MP was 75%, Output level 50%, and then Tascam level at 75%.

soundcloud.com/aeg0/at2021-guitar-tubemp

Any help would be appreciated. Thanks.
 
jake578 said:
The most likely thing, though, is your interface and/or computer. I didn't see mention of an interface. What are you using for that? You can get good, quiet ones for starting at around $100, possibly a bit cheaper. If you already have a decent interface, check your cabling. Mixing balanced and unbalanced cables and gear can cause all manner of noisiness. If it isn't the balance, you might check to see if your audio cables are too close to any power supplies or power cables, and separate them. Finally, if your interface is a USB type, try a different USB port to see if that helps.
Click to expand...

Ken, I'm using the Tascam US-122 mkii, which is a low-end interface for around $150. I also borrowed an Mbox2, which I understand is a decent interface. I already made sure that the audio cables arent close to any power cables. I have tried different USB ports, I dont notice any difference.


Seidy said:
+1. Try to skip Tube MP and see what comes out.
Click to expand...

Seidy, When i skip the Tube MP, the levels are way too low. I have to end up amping them using software, which also amplifies the noise.
 
I had a listen to your samples (and downloaded them for a look in Audition).

It sounds to me like most of the problem is actual room noise (ventilation fans, computer fans and disks, etc.) rather than any electronic noise in your system. The solution I'd suggest is playing with the position and aiming of your mics--if you can figure out the source of the noise (your computer being the most likely culprit) use a longer XLR to get farther away from it and position yourself so the noise source is in the null zone of the microphone (directly behind the mic for cardioid pattern). Depending on how you're placing the mic, you might also be able to get closer to the guitar. I know purists argue that being more distant gives a more "open and airy" sound...but if the open air is fan noise, this isn't a good thing!

A good experiment might be to set you levels as if you were recording, but instead of playing slowly move and aim the mic in various directions to see the effect on the noise. If you use the vertical zoom function on Audition to change the scale, you should be able to see the noise waveform clearly. If you find a position and/or aiming that reduces the background noise, think about using this for recording.

Hope this helps,

Bob
 
All of the above advice is great. And they're right. I've never used noise reduction on any of my recordings. I'll use a noise gate to cut out noise below a certain threshold.

The only time I've used noise reduction is for restoration projects and for editing audio clips.
 
Bobbsy said:
I had a listen to your samples (and downloaded them for a look in Audition).

It sounds to me like most of the problem is actual room noise (ventilation fans, computer fans and disks, etc.) rather than any electronic noise in your system. The solution I'd suggest is playing with the position and aiming of your mics--if you can figure out the source of the noise (your computer being the most likely culprit) use a longer XLR to get farther away from it and position yourself so the noise source is in the null zone of the microphone (directly behind the mic for cardioid pattern). Depending on how you're placing the mic, you might also be able to get closer to the guitar. I know purists argue that being more distant gives a more "open and airy" sound...but if the open air is fan noise, this isn't a good thing!

A good experiment might be to set you levels as if you were recording, but instead of playing slowly move and aim the mic in various directions to see the effect on the noise. If you use the vertical zoom function on Audition to change the scale, you should be able to see the noise waveform clearly. If you find a position and/or aiming that reduces the background noise, think about using this for recording.

Hope this helps,

Bob
Click to expand...

^This^. Bob is absolutely correct. As he always is. :)
 
Thanks for the advice. I'll try moving the mic around, or moving to a different room.

Does my guitar cable or the patch cable (Tube MP to Interface) have to be balanced too? How about XLR - arent they all balanced? Is there any way of knowing whether my current cables are balanced or not?
 
I personally don't mind a bit of noise so long as it's not distracting. Some preamps are noisy, if that is the case just roll with it. If it's room noise try to minimize it, but as long as it's not loud crashing (like my upstairs neighbors all day EVERY day), it won't be a problem. A little fuzz from analog equipment is sometimes even nice. I'm not super hi-fi guy anyway, but that's my advice.
 
aeg0 said:
Thanks for the advice. I'll try moving the mic around, or moving to a different room.

Does my guitar cable or the patch cable (Tube MP to Interface) have to be balanced too? How about XLR - arent they all balanced? Is there any way of knowing whether my current cables are balanced or not?
Click to expand...

I don't hear a bunch of noise having to do with your cables. Mostly the mics picking up room noises. That is the beauty and drawback of condensers. They can pick up a SBD so clear, you can almost smell it. Sit quietly in your room. you can hear a clock ticking, the computer fan running, neighbors talking........ Your mic actually 'hears' better than you do. It then is amplified by gear that gives this noise more gain. Take steps to remove or lessen these noises and your issues will be cut in half.

Your MP is only going to add insult (distortion) to injury with these noises. Don't get me wrong here, I have actually gotten some good things out of similar cheap 'tube claimed' preamps. But not for clean and clear recording of acoustic stuff. Ever. I realize you feel you have an issue with low gain from your preamp. I don't think the problem with your noise is caused by anything other than the room that the noise is coming from.

Kill the noise.........
 
+1 Tube MP is VERY VERY noisy.

It can be a normal step if you have no options in terms of better gear. But if you have good gear, you have no need for it, unless you do something really stupid like set the levels really low and record in 16 bit. But with a chunk of change, lots of good mics with < 5dB noise (A weighted). Combined with other gear that maximizes that and you're in the zone.

I have a radio shack electret that requires it. But it actually takes to it quite well. It's also the last mic that I'd probably use on ANYTHING. Baring some theatrical recreation that needed a sort of blue light special sounding thing.
 
Bobbsy said:
..It sounds to me like most of the problem is actual room noise (ventilation fans, computer fans and disks, etc.) rather than any electronic noise in your system.
Click to expand...
+1
I'd be curious where you had the mic positioned. It sounds fairly close in some respects, yet lots of room noise.

Make some soft panels to mostly suround your recording position. Won't touch rumble' but it'll knock most of the mid and up room return stuff about 50%.

Seems to me the 'MP track has a bit more sparkle. :drunk:
 
You must log in or register to reply here.
Back
Top