... which is normal, because your input signal has a short click, too. A limiter will not elimiate clicks of arbitrary shortness. A lowpass
filter
does that or a clipper.
Ok, thank you for that information.
Attached is a declicked version of your patch, which also has an input declicker.
Thanks! But can anybody help me with my 1st question: how to convert the limitation calculation in decibels back to values that limit the original signal correctly. At the moment, in my patch it doesn't really limit.
Best Mirko
Subtract 3 or 4 dB from the original 90 dB you used for the calculation? It has to do with peak-to-peak, which you need for absolute limiting, versus RMS which is what [env~] gives you, as I mentioned in the first mail...
D.
Mirko Maier wrote:
... which is normal, because your input signal has a short click, too. A limiter will not elimiate clicks of arbitrary shortness. A lowpass
filter
does that or a clipper.
Ok, thank you for that information.
Attached is a declicked version of your patch, which also has an input declicker.
Thanks! But can anybody help me with my 1st question: how to convert the limitation calculation in decibels back to values that limit the original signal correctly. At the moment, in my patch it doesn't really limit.
Best Mirko
Subtract 3 or 4 dB from the original 90 dB you used for the calculation?
I tried to compensate that, but it doesn't have an effect on the calculation.
Attached the last version of my (still not working) limiter. Thanx for any help. Mirko
#N canvas 685 212 1015 802 12; #X floatatom 426 284 5 0 0 0 - - -; #X obj 174 585 *~; #X floatatom 376 223 5 0 0 0 - - -; #X obj 376 172 env~ 64; #X obj 174 140 *~; #X obj 173 38 osc~ 440; #X floatatom 246 97 5 0 0 0 - - -; #X floatatom 426 345 5 0 0 0 - - -; #X floatatom 321 404 5 0 0 0 - - -; #X obj 298 374 *; #X floatatom 349 457 5 0 0 0 - - -; #X obj 301 638 env~ 64; #X obj 175 261 z~ 64; #X obj 375 255 moses 90; #X obj 426 312 expr 90/$f1; #X text 384 405 it's no problem to limit the number stream (limit is 90db); #X text 408 457 but it should be the same here! how convert?; #X text 66 38 test signal; #X obj 376 200 + 3; #X obj 173 736 dac~; #X obj 173 706 *~; #X obj 200 681 tgl 15 0 empty empty empty 0 -6 0 8 -262144 -1 -1 0 1; #X text 415 198 because of peak-to-peak?; #X text 298 96 any amplification , e.g. 4; #X connect 0 0 14 0; #X connect 1 0 11 0; #X connect 1 0 20 0; #X connect 2 0 9 0; #X connect 2 0 13 0; #X connect 3 0 18 0; #X connect 4 0 3 0; #X connect 4 0 12 0; #X connect 5 0 4 0; #X connect 6 0 4 1; #X connect 7 0 9 1; #X connect 7 0 1 1; #X connect 9 0 8 0; #X connect 11 0 10 0; #X connect 12 0 1 0; #X connect 13 1 0 0; #X connect 14 0 7 0; #X connect 18 0 2 0; #X connect 20 0 19 0; #X connect 20 0 19 1;
#X connect 21 0 20 1;
Jetzt kostenlos herunterladen: Internet Explorer 8 und Mozilla Firefox 3 - sicherer, schneller und einfacher! http://portal.gmx.net/de/go/chbrowser
You may want to investigate the relationship between dB and RMS further. Attached is a working patch, however very crudely. Have a look at the numbers given by the [dbtorms] and [rmstodb] objects. Note use of [line~] as well.
best! D.
Mirko Maier wrote:
Subtract 3 or 4 dB from the original 90 dB you used for the calculation?
I tried to compensate that, but it doesn't have an effect on the calculation.
Thank you, but it definitely doesn't limit the signal!
-------- Original-Nachricht --------
Datum: Wed, 26 Aug 2009 12:16:17 +0200 Von: Derek Holzer derek@umatic.nl An: Mirko Maier mirkom@gmx.de CC: pd-list@iem.at Betreff: Re: [PD] limiter questions
You may want to investigate the relationship between dB and RMS further. Attached is a working patch, however very crudely. Have a look at the numbers given by the [dbtorms] and [rmstodb] objects. Note use of [line~] as well.
best! D.
Mirko Maier wrote:
Subtract 3 or 4 dB from the original 90 dB you used for the
calculation?
I tried to compensate that, but it doesn't have an effect on the
calculation.
-- ::: derek holzer ::: http://blog.myspace.com/macumbista ::: http://www.vimeo.com/macumbista ::: ---Oblique Strategy # 173: "Voice your suspicions"
But this one does. Working in RMS values appears to be the solution to your problem.
D.
Mirko Maier wrote:
Thank you, but it definitely doesn't limit the signal!
-------- Original-Nachricht --------
Datum: Wed, 26 Aug 2009 12:16:17 +0200 Von: Derek Holzer derek@umatic.nl An: Mirko Maier mirkom@gmx.de CC: pd-list@iem.at Betreff: Re: [PD] limiter questions
You may want to investigate the relationship between dB and RMS further. Attached is a working patch, however very crudely. Have a look at the numbers given by the [dbtorms] and [rmstodb] objects. Note use of [line~] as well.
Too reiterate, try translating the values you put into your patch between dB and RMS. dB is logarithmic while RMS is linear, so your absolute gain increase of 4 times the original signal translates to 112 dB. 100 dB is the "clipping point", or a Pd signal level of "1", thus 4x the original signal is 12 dB over clipping. And your limiting threshold of 90 dB translates to a scaling factor of 0.316 times the original signal.
Confused? Want a picture?
http://www.phys.unsw.edu.au/jw/graphics/LI.GIF
(Source: http://www.phys.unsw.edu.au/jw/dB.html)
Where the author has written "power", think RMS. So twice the RMS value is an increase of +3 dB. Likewise, half the RMS values is -3 dB. Because you were calculating your limiter entirely in dB, the RMS values needed for correct limiting were all wrong (far too little) so it didn't appear that your limiter was limiting at all!
Best! Derek
Derek Holzer wrote:
But this one does. Working in RMS values appears to be the solution to your problem.
D.
Mirko Maier wrote:
Thank you, but it definitely doesn't limit the signal!
-------- Original-Nachricht --------
Datum: Wed, 26 Aug 2009 12:16:17 +0200 Von: Derek Holzer derek@umatic.nl An: Mirko Maier mirkom@gmx.de CC: pd-list@iem.at Betreff: Re: [PD] limiter questions
You may want to investigate the relationship between dB and RMS further. Attached is a working patch, however very crudely. Have a look at the numbers given by the [dbtorms] and [rmstodb] objects. Note use of [line~] as well.
On Wed, 26 Aug 2009, Derek Holzer wrote:
Too reiterate, try translating the values you put into your patch between dB and RMS. dB is logarithmic while RMS is linear,
dB is a unit of measurement. RMS is a thing you can measure. If you are applying [rmstodb] on a RMS linear amplitude, you get a value in RMS dB, whereas if you are applying [rmstodb] on a peak linear amplitude, you get a value in peak dB. However, the vocabulary used for Pd in this case confuses the concepts and says "rms" to mean "linear amplitude" regardless of whether it's "rms", "peak", "effective", or any other variation on how the unit is used.
Where the author has written "power", think RMS.
So why wouldn't power be the square of linear amplitude instead, as it usually is?... that is, MS, which is RMS without the R... (this also goes with how [dbtopow] and [powtodb] work)
_ _ __ ___ _____ ________ _____________ _____________________ ... | Mathieu Bouchard, Montréal, Québec. téléphone: +1.514.383.3801
Dear Derik,
thank you, that's the solution.
Mirko
-------- Original-Nachricht --------
Datum: Wed, 26 Aug 2009 12:59:20 +0200 Von: Derek Holzer derek@umatic.nl An: Mirko Maier mirkom@gmx.de CC: pd-list@iem.at Betreff: Re: [PD] limiter questions
But this one does. Working in RMS values appears to be the solution to your problem.
D.
Mirko Maier wrote:
Thank you, but it definitely doesn't limit the signal!
-------- Original-Nachricht --------
Datum: Wed, 26 Aug 2009 12:16:17 +0200 Von: Derek Holzer derek@umatic.nl An: Mirko Maier mirkom@gmx.de CC: pd-list@iem.at Betreff: Re: [PD] limiter questions
You may want to investigate the relationship between dB and RMS
further.
Attached is a working patch, however very crudely. Have a look at the numbers given by the [dbtorms] and [rmstodb] objects. Note use of [line~] as well.
-- ::: derek holzer ::: http://blog.myspace.com/macumbista ::: http://www.vimeo.com/macumbista ::: ---Oblique Strategy # 83: "How would someone else do it?"
-
Derek Holzer -
Mathieu Bouchard -
Mirko Maier