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Topic: Balance steps (Read 1411 times) previous topic - next topic
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Balance steps

Hello.

How to low audio sound volume if I want the steps to be even?

I have eight (8) mono/16bit/44100/wav -audio files and I want to make them to stereo and use panning/balance effect.
Example, first file both channels are equally loud and you feel like you are in the middle.
Then, the second file left or right channel is little bit muted, so the balance is little bit left or right.
And last file is totally left or right panned/balanced.
But what is the step size between totally center and totally left/right?

I know that human ear is not linear and I probably have to use decibels, instead of percentage or 16bit/32768 values.
And the audio source is human (female?) voice, normal speak, so the frequence is about ~200Hz.

I might use more or less files than eight, so it might be a good idea to know the calculation value rather than pre-calculated copy/paste.

I'm using Audacity and Sox.exe.

Little bit off topic, but how to make multichannel (5.1, etc.) .wav file if I want to make more than two channels (stereo).
I know how to add channels, but how can I specify which channel is which (FL, FR, FC, LFE, etc.)?

Re: Balance steps

Reply #1
-3dB is half power and +3dB is double the power...    So if you have 50W coming from each speaker that's 100W total.    If you pan fully to one side you'll need to increase that speaker by +3dB maintain 100W.  This is called the "-3dB pan law".  

But there are psychoacoustic effects and you may not perceive constant power so many DAWs have a choice of pan laws. 

Note that with digital files you have to watch out for clipping when you boost one side.   (Mixing can also result in clipping.)

So the compliment of +3dB is minus infinity dB.    (By the time you get to -20dB relative to the opposite channel you won't hear anything from the -20dB speaker.)     The perceived pan-position isn't very precise and it depends on the speaker/listener position, room acoustics, and the listener.   With a 1 or 2dB difference it will probably sound like it's coming from around the center and with a 10dB difference it will probably sound like it's coming from one speaker.

You can make a spreadsheet.    I did that once but I don't have it now.

There are two formulas for decibels -
For power, dB = 10 X log(P/Pref)
Power ratio = 10 to the power of (dB/10)

For amplitude (voltage or digital levels), dB  = 20 X log(A/Aref)
Amplitude Ratio = 10 to the power of (dB/20)

You'll want to use the power ratio formula and you can just use a ratio or "assume" or "normalize" for 1 Watt.

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Little bit off topic, but how to make multichannel (5.1, etc.) .wav file
In Audacity, Edit -> Preferences -> Import/Export -> Use Advanced Mixing Options.

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But how can I specify which channel is which (FL, FR, FC, LFE, etc.)?
Audacity doesn't specify so you'll probably just have to do an experiment.   (Note that Audacity doesn't support surround-sound playback itself so you'll have to export and check on something that can play multi-channel/surround.)

Re: Balance steps

Reply #2
I have no idea what your source is.
Even if you find mixing formula that sounds good on one set of files, it might sound bad on another set of files.
You said you are using Audacity.



Drag all of your files into Audacity and play with sliders on the left side. You can do it in real-time.
Once you are happy with results you can downmix everything into stereo.
gold plated toslink fan

Re: Balance steps

Reply #3
Thanks @DVDdoug

I forget that sound perception also depends the volume level and human ear/hearing isn't linear.
I'll have to do some experiments, maybe -1dB, -2db, -3dB, ... or -3dB, -6dB, -9dB, ... from the full scale and "see" how it sounds.

The presumption is that the listener is wearing a headset or is positioned middle of the speakers.
And the speakers are approx 1-2 meters (3-6 feet) in front of you.
So the total power of the speakers is quite low (~10W?).

The goal is to hear the difference between these eight files without knowing the panning/balancing parameters.

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Audacity doesn't specify so you'll probably just have to do an experiment.
The problem is that I only have stereo devices (2.0), but plan is to get multichannel system in the future and before that get some experience.

@Markuza97
Quote
Even if you find mixing formula that sounds good on one set of files, it might sound bad on another set of files.
That is what I'm afraid of :)

For more detailed information to my question, I am making a co-driver sounds to rally game.
Normally, the sounds are mono, but it might be a good idea to use panning/balancing effect to them, depends which way the road is turning and how sharp it is.

Re: Balance steps

Reply #4
You are saying that game is using mono sounds. Are you sure that stereo or multichannel is supported?
If it only supports mono, then you cannot do anything about it. Mono will always be centered.
Game engine is doing the mixing, and it is probably hardcoded, so you cannot do anything about it.

gold plated toslink fan

Re: Balance steps

Reply #5
Quote
The goal is to hear the difference between these eight files without knowing the panning/balancing parameters.
Theoretically (ignoring any unpredictable psychoacoustic effects) if you want constant loudness you'd want constant power which you can calculate from the dB power formula.   i.e, If you start with 100% in one channel that calculates as 0dB in one channel and minus infinity dB (silence) in the other channel (you'll get an error if you try to calculate minus infinity).    50/50 would be -3dB (half power) in both channels.   75% & 25% calculates as -1.25dB and -6dB.

For example, calculating 50% or half power is 10 x log(0.5) = -3dB.

The same concept will work for multi-channel.  20W (or 20%) from 5 channels is the same as 100W (or 100%) from one channel.

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The problem is that I only have stereo devices (2.0), but plan is to get multichannevl system in the future and before that get some experience.
OK, I have a Dolby test disc and I opened it in Audacity.  From top to bottom the tracks are:
Left Front
Right Front
Center
LFE
Left Surround
Right Surround





Re: Balance steps

Reply #6
@DVDdoug

10 x log (0.5) =  -3.010 dB

10 x log (0.6) =  -2.218 dB
10 x log (0.4) =  -3.979 dB

10 x log (0.7) =  -1.549 dB
10 x log (0.3) =  -5.228 dB

10 x log (0.8) =  -0.969 dB
10 x log (0.2) = - 6.989 dB

10 x log (0.9) =  -0.457 dB
10 x log (0.1) = -10.000 dB

10 x log (1.0) =   0.000 dB

@Markuza97

You are right.
I tested and the game doesn't support stereo sounds in pacenotes.
Even when I convert all game audio files same parameters (I have a script.cmd).

I did make a assumption, because frontend music is originally stereo and I can panning/balancing these sounds.

The game has surround sound system (Creative EAX 3.0), but it is legacy and I don't know how it works.
Maybe I can use Indirectsound? https://www.indirectsound.com/

But I might have other purposes for panning/balancing -effects, so this topic wasn't useless.