Old 05-11-2011, 01:08 PM   #1
snatchman
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Default Reaper's Pan Law..?

Hello..Question if I may: I've readwhere in the pan law can effect the sound quality of a DAW's performance ( audio)..Is there such a thing in Reaper..? If so, how do you go about changing/eperimenting with the pan law in Reaper.? Or...is it something better off left to the Pros....? Thanks..
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Old 05-11-2011, 01:36 PM   #2
Blechi
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You can change the pan law globally in the project settings or on a per track basis by rightclicking a track's pan slider.

Happy experimenting.
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Old 05-11-2011, 01:48 PM   #3
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i leave mine a -3db fwiw globally
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Old 05-11-2011, 01:51 PM   #4
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Originally Posted by Blechi View Post
You can change the pan law globally in the project settings or on a per track basis by rightclicking a track's pan slider.

Happy experimenting.
Hey Blechi..Thanks..!..So, I can just try one channel's fader to see if there's any different without effecting the others and when you say global, that changes them all at once..?
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Old 05-11-2011, 02:37 PM   #5
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Hello..Question if I may: I've readwhere in the pan law can effect the sound quality of a DAW's performance ( audio)..Is there such a thing in Reaper..?
No... It shouldn't affect "sound quality" at all! Panning is simply adjustment of the signal level in the channels. Level adjustment is the most basic thing you are doing when mixing and it's a lossless process inside any DAW or audio editor that uses 32-bit or 64-bit floating-point data/operations. (And, I don't know of any audio editors that don't use floating-point.)

And, if you are permanantly-positioning a sound in the mix, pan law shouldn't matter either, except you might need to adjust your fader if you move your pan control.

If you are moving a sound around during the song, pan laws are important because they effect how the overall sound-level changes as you pan.

Last edited by DVDdoug; 05-11-2011 at 02:42 PM.
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Old 05-11-2011, 10:59 PM   #6
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No... It shouldn't affect "sound quality" at all! Panning is simply adjustment of the signal level in the channels. Level adjustment is the most basic thing you are doing when mixing and it's a lossless process inside any DAW or audio editor that uses 32-bit or 64-bit floating-point data/operations. (And, I don't know of any audio editors that don't use floating-point.)

And, if you are permanantly-positioning a sound in the mix, pan law shouldn't matter either, except you might need to adjust your fader if you move your pan control.

If you are moving a sound around during the song, pan laws are important because they effect how the overall sound-level changes as you pan.
"No... It shouldn't affect "sound quality" at all! Panning is simply adjustment of the signal level in the channels. "

Hello..Thanks for you reply.Do you mean fader volume.? As I asummed panning was just a left to right move or is that considered volume in the DAW world as I'm coming from analog..?.Thanks..!
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Old 05-11-2011, 11:02 PM   #7
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i leave mine a -3db fwiw globally
Hello. Thanks for your reply...So I asumme the nominal reference is "0"..?..Thanks...
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Old 05-12-2011, 06:53 AM   #8
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Hello..Thanks for you reply.Do you mean fader volume.? As I asummed panning was just a left to right move or is that considered volume in the DAW world as I'm coming from analog..?.Thanks..!
If you have a single source, going to two speakers at the exact same volume, the resulting sound will be louder than either of the speakers alone. To compensate for this, mixers (DAW or otherwise) incorporate a "pan law" so that as you move the pan toward center, the signal is attenuated by xxdB so that as you pan from hard left to hard right, the reletive volume stays the same.
Theoretically in a perfect environment the difference "should" be 6dB, however since no environment is perfect, it is often closer to 3dB.
That combined with the fact that a signal being passivly split, loses 3dB, means that in an analog circuit a 3dB pan law pretty much happens on it's own, and is fairly accurate in most listening spaces. So the default pan law on most mixers and DAWs (including Reaper) is 3dB. However, there are instances where you may want to change that (on stereo sources for instance), so Reaper has the option of changing it.
But as DVDdoug said, it is only an issue if you need to move the pan knob without affecting the mix.
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Old 05-12-2011, 07:51 AM   #9
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i leave mine a -3db fwiw globally
Something to bear in mind though is that this is okay for tracks with mono output, but tracks with stereo output need to be set to 0.
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Old 05-12-2011, 09:02 AM   #10
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Originally Posted by DVDdoug View Post
No... It shouldn't affect "sound quality" at all! Panning is simply adjustment of the signal level in the channels..
Pan law can affect the volume and the volume can affect the perceived quality (generally speaking, things louder sound "better")...
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Old 05-12-2011, 09:11 AM   #11
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Something to bear in mind though is that this is okay for tracks with mono output, but tracks with stereo output need to be set to 0.
This is true, but only if you have a "balance" style pan (which Reaper 3.x does). If youhave a true stereo pan (which Reaper 4 Beta has the option of) then you are panning each channel (l and r) individually essentially as two mono sources, in which case, panning one hard right and the other center, will result in a boost of the one panned center if a 0dB pan law is applied.
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Old 05-12-2011, 07:39 PM   #12
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Shucks..Just as I suspected..Leave it to the Pros...! (lol)
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Old 11-12-2012, 03:59 PM   #13
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Theoretically in a perfect environment the difference "should" be 6dB, however since no environment is perfect, it is often closer to 3dB.
Ok, with the proviso that I'm no expert in audio engineering (in fact, I'm no audio engineer at all!): I'm going to bite here because although this is an old post, it's also the first post I found when googling 'reaper pan law' so others will probably be referring to this post, too.

Let me start by saying, if reality differs from your theory by 3db, then maybe it's time for a new theory :-)

Now, if you play the same sound through two loudspeakers (instead of one) then you are essentially outputting twice the audio power into the room than you were before, since the speakers behave essentially independently. Put simply, if you put 100W into one speaker, then some (small) number of watts of sound energy will be radiated (the exact number dependent on the speaker sensitivity). If you put 100W each into two speakers (so 200W in total) then twice the total audio power is radiated (since the speakers' sensitivity hasn't changed, so each speaker will now output the same number of watts of sound as the single speaker did previously; twice the electrical power in in total, twice the sound power out in total). Twice the power equals 3db. So your sound pressure levels in the room will be 3dB louder, if you just played the signal, unchanged, through two speakers instead of one. (But see the footnote.)

Now, it's true, if you take the same stereo signal that was used in the above experiment, and convert it to mono the 'normal' way (i.e. by simply summing the two channels) then having the signal on both channels gives you twice the signal level, which equals four times the power or 6db (power goes as signal squared).

Yes, it's true, doing the experiment through stereo speakers gives a different result from converting the stereo signal to mono and playing that; that's because converting a stereo signal to mono makes it sound different from the original stereo source (but you knew that already). And one effect of that is that it makes sounds panned to the centre 3db louder than they did before conversion.

But anyway, playing a sound through both channels normally makes the result 3db louder (unless you're doing any subsequent processing that combines the channels again). Hence a -3dB pan law (which reduces the levels by 3dB when you pan to the centre) makes sense for the normal case - it keeps the sound pressure level constant as you pan given reasonable assumptions about the playback environment.

Quote:
That combined with the fact that a signal being passivly split, loses 3dB
That's true for certain kinds of signals, like radio frequency signals, where when you put then through an inductive splitter half the power goes down one route, and half down the other. But inductive splitters aren't really relevent to audio work.

For normal line-level audio signals, with a low impedance output and a (relatively) high impedance input, splitting a signal has no effect on levels. If my output is 0.7 volt RMS and I plug it into an input, that input sees 0.7 volt RMS. If I split it by a Y-cable into two inputs, both inputs see 0.7 volt RMS.

Put another way, normally with audio, it's levels that you're sending, not power. They actually work quite a lot like digital signals - you're just sending information, it's just the way you encode it that differs.

Corrections welcome, but I think the above is broadly correct

Regards

roy

Footnote:

Now, if you did the above experiment in an anechoic chamber, using a sine wave as your source, and moved a microphone about, you would find something interesting. At some points in the room, the signals would contructively intererfere - they would sum - and you would get the same 6dB effect that the stereo-to-mono conversion gives you. And in other locations, the signals would destructively interfere (because they'd be out of phase), and they'd completely cancel out resulting in silence. So although in total it's still true that you'd be putting out the twice the power - in some place you'd get four times the power (+6dB) and in others you'd get silence (-infinity dB).

In practice, in the real world, interference effects are rarely significant (and then only at very high frequencies). But interference effects are the reason you can never find the lost smoke alarm or other high-pitched beeping device - the sound gets quieter and louder as you move about - without giving you any clear idea as to where the source is.

[Edited slightly to correct and clarify]

Last edited by Roy Badami; 11-16-2012 at 04:41 PM.
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