Increasing sound by bouncing?

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microchip

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The situation...

I have a few cases where some of my tracks were recorded at low levels and to raise them up to where I need them to be also creates background hum/hiss.

However, when I bounce either a single track or an entire set of tracks to another track within the recording, then I basically double the sound.

Is this a good way to increase volume without increasing floor noise? And since I am doing it digitally, I would not think that mixing down the bounced tracks and the original tracks together would cause any drop in quality of the sound...would it?

Micro
 
Bouncing is no different from "mixing down". You are basically just creating a project from mixdowns. This doesn't mean anything necessarily has to suffer (in the digital realm), but it does of course mean that you lose control of the details, which might result in a poor mix.

It sounds like your talking loud as in average level and/or perceived loudness. That is, you might have a guitar track that's peaking near 0db, but it doesn't sound very loud. This is where you need to try two things, in this order:

1) Try to make a "louder" guitar sound. Remember, loud doesn't just mean "level"...the human ear doesn't hear all frequencies equally. It is possible to hear two sounds at exactly the same level of volume, and to perceive one as being louder than the other...it's common in fact.

2) Throw a compressor into your signal *before* going to tape. You could compress after the fact if your noise floor wasn't so high. Are you recording on a PC? If so, you should really consider investing in a good soundcard and suddenly your problems will be quite easy to fix.

Slackmaster 2000
 
Ooops, I just realized you said "some of your tracks". I still think you should probably invest in a better soundcard.

There is no good way to do this....you can try a gate or manually silencing the dead parts of the track so that the hiss is only heard when the instrument is playing. Other than that, your only good option is to retrack. Noise reduction units are horrible.

With a decent 24bit soundcard, your noise floor will drop so low that it won't be nearly as big a deal if you accidentally track a little low.

And pay attention to your levels. Retrack if they're not there!

Slackmaster 2000
 
Slack...

I have been perplexed by this issue...and I will go into it a little further.

I do have a Delta 44 soundcard and I am recording at 24bit. The problem is that I have 2 synths going into the Delta, but very rarely do they seem to get up to 0 levels, even with the volume on the synths turned up all the way. Because of the type of music I do, alot of the soudns I use as my main sounds are usually what others use as background sounds. And it are these sounds (like pads) that get poor levels when I record. That only leaves me to turn up the trim in my Cakewalk settings, which in turn increases the floor volume.

That is what prompet this question and perhaps you might have some further advice...I have thought about getting an Audio Buddy to increase my input. Your thoughts on that?

Micro
 
Micro - When you "bounce" a single track, you are in essence just doubling the track (assuming you keep the original in the mix). While that would, of course, double the volume, it should also double the noise.

I don't understand why you say you get more noise when you raise the volume of your original track, but you do not get more noise when you double (bounce) the track. Seems to me you're doing essentially the same thing.
 
I agree with Slack and dachay2tnr. Bouncing isn't going to help. Your noise will be noise whether you physically increase the gain or if you bounce the track (effectively doing the same thing).

Couple of things...


1) Your signal doesn't need to be at 0db. Remember that anything above 0 is your clipping point (in most cases), and you want to make sure you don't spike above that. At 24 bit, you can never go above -3db and still have a solid track.

2) If your snyth is cranked when you're tracking, then that's probably where your noise is coming from. I've never used a synth that had an output that low, but have heard of the problem before. Sounds like you need a pre. The volume on your synth shouldn't need to get over about 1/2 volume, 3/4 at the absolute extreme.

3) Also, like Slack was explaining, you can do other things to your track to raise it's "percieved" loudness - things like careful EQ cuts from other instruments, panning, etc...
 
Oh, I see what you're saying. Did you set the Delta input to -10? That's the first thing I would check.

I would assume your synths output somewhere near line level (-10/+4 or somewhere in between). If for some reason they're not putting out enough level, maybe because they're noisy at higher volume or whatever, then *sometimes* a preamp or line level preamp will help.

An audio buddy is an adequate starter microphone preamp, but you might overload its input with a source near line level. You won't damage it, but it would sound bad. (it really depends on what the buddy can handle, it was designed to be multi-purpose). Otherwise there are line level preamps out there...but first I would want to understand why your signals are so low. It could be that you need to switch the delta input to -10, in which case no additional amplification would be needed. It could be that your synth is noisy when you increase volume, but this noise might always be present and amplifying a weak signal even with a clean preamp might just put you back where you started.

Also, why are you bouncing. You should only bounce if your computer cannot handle your project size.

Slackmaster 2000
 
I have no idea why I said bouncing...I should merely have said copy and paste. In other words I simply cut the clips from one track and paste them into another so the tracks are identical...did not mean to say bounce. I don't bounce my tracks (I was actually helping someone else on the topic of bouncing and had it on my brain).

And yes, the Delta is set at -10

And the 2 synths are a Roland RS-5 and the Korg MS2000.

One thing that may be of interest... when I play the lead sounds on these instruments (like synth and guitar) recording level is not a problem. Only when I record these 'ambient' type sounds is this a problem (and when I say low levels, I am talking about getting a -12 signal with the synth all the way up).
 
-12db shouldn't be bad with a Delta44, who's noise floor should be well under -75db.

Doubling your tracks is effectively the same thing as increasing a single track's level by 6db with a fader, except that you risk phase issues if the software doesn't do it exactly right.

Are you competing with the noise of your synths, or the noise of the Delta?

Slackmaster 2000
 
I find that most keyboards need a mixer/preamp to boost the levels a bit. If you have the volume cranked and are trying to play some soft passages then the level will be too low.

You might also make sure that volumes are up in the individual patches. Sometimes they lower the volume of certain patches so they match better for live performance but that eats up your SNR when you are recording.
 
It seems likely that the noise would be from the synth simply because I do have it turned up all the way. I have changed the meter readings, and with the synth up that high I usually have floor noise at about -60, but it goes away when the synth is turned off or I turn the volume knob down.

So, it seems getting a pre for the synths would be ideal. But, if I have 2 synths and 4 cables going to the Delta, would I then need 2 pre units?
 
Try editing the patches on the synth. It may be that the soft patches were programmed with their volume low so as to be softer when used live, without having to quickly adjust volume after the patch change.
RD
 
If you’re doing midi sequencing where you can exactly replicate the synth line you’re recording, you do have a chance of reducing the noise level by mixing down multiple takes.

Here’s how it could work:

  • Step 1. Begin the sequence with a sharp high frequency cracking sound that will be used to synchronize all the recorded takes.

    Step 2. Record several identical tracks, the more the better.

    Step 3. Use the very start of the cracking sound to align all the tracks as closely as possible.

    Step 4. Mix them down and you will have less noise!
"Huhhh… why should this work… aren’t you just adding up the noise too?"

Yes the noise from all the tracks gets multiplied as well, but it’s different than the keyboard signal. The noise on each track is random and, therefore, uncorrelated with the noise on the other tracks. When you add two equally loud uncorrelated signals together the RMS amplitude increases by +3db. The keyboard signals, on the other hand, are essentially identical. And if you go to the effort of carefully synchronizing the tracks, they will be phase correlated as well. When you add two identical phase correlated signals together the RMS amplitude increases by +6db. That’s +3dB more than the noise increase. So adding together two identical separately recorded tracks increases the signal to noise ratio by 3dB. Every subsequent doubing of the number of tracks raises the S/N by another 3dB.

So the S/N increase goes like this:

  • 2 tracks -> 3dB
    4 tracks -> 6dB
    8 tracks -> 9dB
    ....etc.
The really nice things about this method is that, unlike filtering or gating; the noise reduction occurs across the entire spectrum; noise is reduced at all signal amplitudes, not just when the signal drops below the threshold; and low level signal is not chopped off with the noise.

The downsides are that the slight but inevitable errors in track alignment will create uncorrelated phases in the very high frequencies. So, there will be high frequency attenuation (in practice this will likely become significant above 10kHz). And, of course, it’s just a lot more work. But nothing good ever comes for free.

I’m not 100% sure if this addressed your initial question microchip, but if it didn’t it’s at least an interesting little footnote.:)

barefoot
 
Cool Barefoot. I think you're smarter than I am. I would never have thought of that.


Matty
 
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