Inverting or Non-Inverting modules?

Maddogg6 · Nov 10, 2005, 11:43 PM

In audio electronics - the 'phasing' of stages is a critical design criteria...

I was playing around with paralleling various EQ/Filters for multi-band compression/limiting and at times, seem to hear what I think is a combinaion of delay and (because of that) phase 'distortions' - then I noticed the 'Phase' plug-in - which I assume (???) inverts the phase. Its more useful to know when a module will invert as such and what kind of delay a module may introduce.

Is there an easy way to see how a plugin behaves in this way?

Also, can this 'delay' be forcasted by the number of 'INSTR' (or other resources) a plugin uses? - as it would seem that those INSTR would equate to a time delay for the signal to enter then exit that module. How far off am I on my way of thinking on this?

Russ · Nov 11, 2005, 12:22 AM

I do not think it is as simple as that. There are a number of ways to delay a signal. I think you would have to understand the DSP processor, the DSP instructions, and each filter (and also consider that some filters only delay part of the signal), etc. in order to try and calculate the delay from each plugin.

BTW: Regarding the phase plugin, you are right about what it is doing:
outl = 0 - (inl * 1);
outr = 0 - (inr * 1);

Tril · Nov 11, 2005, 07:49 AM

There's no delay between the time the signal enters and exit a plugin. Except if the plugin is made in a way that adds a delay (a delay filter, etc). All the code in all the DSP gets executed once for every sample. The emu10kX can execute all the 512 (or the number you have, I have 512) instruction for every sample.

Maddogg6 · Nov 11, 2005, 09:42 PM

Oh ok - thanks for the reply guys.

The 'phase filtering' Im hearing must be artifacts from DSP techniques/routines used with in a KX plugin/module.

I guess I was wondering if was hearing was a 'bug' or 'normal' - Ill sumize - normal.
I got confused a bit because phase plugin didnt seem to correct what I was hearing.

Russ · Nov 11, 2005, 11:03 PM

Have you checked out the AS10k1 manual? There is some good info in that you might find useful.

As Tril indicated, each of the instructions is executed for every sample, but you have to understand how the plugin (filter) works (as well as the DSP), in order to know if it will delay the siganl (which is what I was getting at with my previous reply).

i.e. Consider a plugin like the FxRouter. In that plugin, the signal enters and exits the same plugin mutiple times (going through other plugins on the way). Because of this (and the order in which the instructions of each plugin get executed, etc), even though the plugin does not really do anything to the signal itself (other than routing) there is a small delay (for each send/return that is used).

Maddogg6 · Nov 12, 2005, 04:47 AM

I was hoping that a simple 'sign' would indicate phase and/or ammount of delay introduced by a plugin. Nothings ever that simple i guess..lol leave it to a green horne to over simplify a complex subject

Oh and thanks for the link - but Ill admit a lot of the docs I have read are difficult to comprehend. I just seem to have trouble grasping this stuff.

Nov 10, 2005, 11:43 PM	#1
Maddogg6 Tail Razer Join Date: Jun 2005 Location: Bernyurass, AZ - USA Posts: 4,027 Rep Power: 50	Inverting or Non-Inverting modules? In audio electronics - the 'phasing' of stages is a critical design criteria... I was playing around with paralleling various EQ/Filters for multi-band compression/limiting and at times, seem to hear what I think is a combinaion of delay and (because of that) phase 'distortions' - then I noticed the 'Phase' plug-in - which I assume (???) inverts the phase. Its more useful to know when a module will invert as such and what kind of delay a module may introduce. Is there an easy way to see how a plugin behaves in this way? Also, can this 'delay' be forcasted by the number of 'INSTR' (or other resources) a plugin uses? - as it would seem that those INSTR would equate to a time delay for the signal to enter then exit that module. How far off am I on my way of thinking on this?

Nov 11, 2005, 12:22 AM	#2
Russ HardwareHeaven Extreme Member Join Date: Jan 2005 Posts: 5,507 Rep Power: 61	I do not think it is as simple as that. There are a number of ways to delay a signal. I think you would have to understand the DSP processor, the DSP instructions, and each filter (and also consider that some filters only delay part of the signal), etc. in order to try and calculate the delay from each plugin. BTW: Regarding the phase plugin, you are right about what it is doing: outl = 0 - (inl * 1); outr = 0 - (inr * 1);

Nov 11, 2005, 07:49 AM	#3
Tril S-3D enthusiast Join Date: Sep 2004 Location: Canada Posts: 1,675 Rep Power: 62 System Specs	There's no delay between the time the signal enters and exit a plugin. Except if the plugin is made in a way that adds a delay (a delay filter, etc). All the code in all the DSP gets executed once for every sample. The emu10kX can execute all the 512 (or the number you have, I have 512) instruction for every sample.

Nov 11, 2005, 09:42 PM	Thread Starter #4
Maddogg6 Tail Razer Join Date: Jun 2005 Location: Bernyurass, AZ - USA Posts: 4,027 Rep Power: 50	Oh ok - thanks for the reply guys. The 'phase filtering' Im hearing must be artifacts from DSP techniques/routines used with in a KX plugin/module. I guess I was wondering if was hearing was a 'bug' or 'normal' - Ill sumize - normal. I got confused a bit because phase plugin didnt seem to correct what I was hearing.

Nov 11, 2005, 11:03 PM	#5
Russ HardwareHeaven Extreme Member Join Date: Jan 2005 Posts: 5,507 Rep Power: 61	Have you checked out the AS10k1 manual? There is some good info in that you might find useful. As Tril indicated, each of the instructions is executed for every sample, but you have to understand how the plugin (filter) works (as well as the DSP), in order to know if it will delay the siganl (which is what I was getting at with my previous reply). i.e. Consider a plugin like the FxRouter. In that plugin, the signal enters and exits the same plugin mutiple times (going through other plugins on the way). Because of this (and the order in which the instructions of each plugin get executed, etc), even though the plugin does not really do anything to the signal itself (other than routing) there is a small delay (for each send/return that is used).

Nov 12, 2005, 04:47 AM	Thread Starter #6
Maddogg6 Tail Razer Join Date: Jun 2005 Location: Bernyurass, AZ - USA Posts: 4,027 Rep Power: 50	I was hoping that a simple 'sign' would indicate phase and/or ammount of delay introduced by a plugin. Nothings ever that simple i guess..lol leave it to a green horne to over simplify a complex subject Oh and thanks for the link - but Ill admit a lot of the docs I have read are difficult to comprehend. I just seem to have trouble grasping this stuff.