Surrounder produces clipping!

dan_the_man · Jul 27, 2003, 06:55 PM

Especially to Eugene and Max

I've connected Peakmeter to all surrounderoutputs
and the wavegenerator(squarewave) to the L R inputs.
surrounder is in 2.0 speaker mode.
If i turn on 'use sub/lfe channel' and 'bass redirection'
of course I get output to the SW channel but I also get higher levels
on the frontchannels.
changing the splitfrequency has effect on both the front and SW volumes,
which should not imho for the front channels...

can anybody explain?

Max M. · Jul 27, 2003, 07:05 PM

>which should not imho for the front channels...

it should.

dan_the_man · Jul 27, 2003, 07:15 PM

I thought the deeper frequencies should be taken away from the main (front) channels and send instead to SW. So the main mix could keep the level or decrease but in now way should it increase! Am I totally wrong? maybe U have a longer explanation for me? thx. dan.

Max M. · Jul 27, 2003, 07:30 PM

>So the main mix could keep the level or decrease but in now way should it increase! Am I totally wrong?

No, you are absolutely right. The problem is that the "peak level" is not the same is "volume level" especially for the square wave signal... actually it's a looong story to explain but in short... Signals that have a lower _volume_ can have higher _peak_ level and vice-versa... Typically when you modify a square waveform in any way except plain "gain" function, the _peak_ level of result is typically higher then the _peak_ level of original square due to phase (and other) changes - even if you know that you _remove_ something from square and the actual _level_ is reduced - this is mostly due to very synthetical nature of the square but could be applicable to many other types of signal as well... Well, it's really hard to explain in short - (It's a "Findametals of Signal Theory" actually - probably someone could explain this better) but you can see all that in action with yourself:

Set the output of wavegenerator to -6db (for example) and record front outputs of the surrounder with and without bass redirection.. Compare the recorded waveforms visually....

Well, this is really the thing to always keep in mind - for example if you even _reduce_ the gain of some band in equalizer (and the average level - e.g. volume - goes lower) the clipping still could occure - this is digital world...

Jul 27, 2003, 06:55 PM	#1
dan_the_man DriverHeaven Junior Member Join Date: Jul 2003 Location: Berlin Posts: 33 Rep Power: 0	Surrounder produces clipping! Especially to Eugene and Max I've connected Peakmeter to all surrounderoutputs and the wavegenerator(squarewave) to the L R inputs. surrounder is in 2.0 speaker mode. If i turn on 'use sub/lfe channel' and 'bass redirection' of course I get output to the SW channel but I also get higher levels on the frontchannels. changing the splitfrequency has effect on both the front and SW volumes, which should not imho for the front channels... can anybody explain?

Jul 27, 2003, 07:05 PM	#2
Max M. h/h member-shmember Join Date: Dec 2002 Location: Evil Empire Posts: 2,639 Rep Power: 69	>which should not imho for the front channels... it should. __________________

Jul 27, 2003, 07:30 PM	#4
Max M. h/h member-shmember Join Date: Dec 2002 Location: Evil Empire Posts: 2,639 Rep Power: 69	>So the main mix could keep the level or decrease but in now way should it increase! Am I totally wrong? No, you are absolutely right. The problem is that the "peak level" is not the same is "volume level" especially for the square wave signal... actually it's a looong story to explain but in short... Signals that have a lower _volume_ can have higher _peak_ level and vice-versa... Typically when you modify a square waveform in any way except plain "gain" function, the _peak_ level of result is typically higher then the _peak_ level of original square due to phase (and other) changes - even if you know that you _remove_ something from square and the actual _level_ is reduced - this is mostly due to very synthetical nature of the square but could be applicable to many other types of signal as well... Well, it's really hard to explain in short - (It's a "Findametals of Signal Theory" actually - probably someone could explain this better) but you can see all that in action with yourself: Set the output of wavegenerator to -6db (for example) and record front outputs of the surrounder with and without bass redirection.. Compare the recorded waveforms visually.... Well, this is really the thing to always keep in mind - for example if you even _reduce_ the gain of some band in equalizer (and the average level - e.g. volume - goes lower) the clipping still could occure - this is digital world... __________________ Last edited by Max M.; Jul 27, 2003 at 10:19 PM.

Jul 27, 2003, 07:15 PM	Thread Starter #3
dan_the_man DriverHeaven Junior Member Join Date: Jul 2003 Location: Berlin Posts: 33 Rep Power: 0	I thought the deeper frequencies should be taken away from the main (front) channels and send instead to SW. So the main mix could keep the level or decrease but in now way should it increase! Am I totally wrong? maybe U have a longer explanation for me? thx. dan.