11 Sep
2008
11 Sep
'08
4:50 p.m.
2008/9/10 Fons Adriaensen <fons(a)kokkinizita.net>et>:
On Wed, Sep 10, 2008 at 01:01:58PM +0200, Martin Horn
wrote:
Someone wrote a kind of tutorial some time ago:
http://ardour.org/node/405
Would be nice to have this as jack-rack file or in rackarrack.
exciter : audio-signal => highpass
=> dissortion => add to audio-signal
enhancer: audio-signal => (different) bandpass filters => dissortion
=> add to audio-signal
(so described in wikipedia)
I don't know if such a thing exists for the
linux audio world, but to get
the effect of an exciter you basically need multiband dynamics. That is a
compressor/ expander that works in multiple frequency bands which are
separated by crossovers.
That would be more a 'compellor' than an exciter.
Easy to confuse, both are originally from Aphex.
11 Sep
11 Sep
8:40 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user Digest, Vol 19, Issue 9
Back on Thursday 11 September 2008, Emanuel Rumpf was like:
2008/9/10 Fons Adriaensen
<fons(a)kokkinizita.net>et>:
Exciter has nothing to do with dynamics. And not really anything to do with
distortion so much as harmonics.
You use a harmonics generator, cut the fundamental, and add in odd ordered
harmonics, with each successice odd harmonic going in opposite directions.
The lower order harmonics are not very noticeable, but very smooth. The
higher order harmonics are much more noticeable, but very abrasive sounding.
I generally use all of the first, and about half of the third.
It goes:
original signal => high pass filter => harmonics generator => attenuator
(variable depending on how much you want to add in) => mix back in with
original signal.
Here's a jack-rack file demonstrating it. Route your source into the
jack-rack, and then direct jack-rack's output to the same destination as your
source. Change levels on the "simple amplifier" to adjust how much you need
added back in.
You need the proper ladspa plugins installed for this...
-Reuben
On Wed, Sep 10, 2008 at 01:01:58PM +0200, Martin
Horn wrote:
Someone wrote a kind of tutorial some time ago:
http://ardour.org/node/405
Would be nice to have this as jack-rack file or in rackarrack.
exciter : audio-signal => highpass
=> dissortion => add to audio-signal
enhancer: audio-signal => (different) bandpass filters => dissortion
=> add to audio-signal
(so described in wikipedia) I don't know if such a thing exists for the
linux audio world, but to
get the effect of an exciter you basically need multiband dynamics. That
is a compressor/ expander that works in multiple frequency bands which
are separated by crossovers.
That would be more a 'compellor' than an exciter.
Easy to confuse, both are originally from Aphex. 
9:14 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user Digest, Vol 19, Issue 9
On Thu, Sep 11, 2008 at 05:36:26PM -0500, Reuben Martin wrote:
Exciter has nothing to do with dynamics.
True.
And not really anything to do with
distortion so much as harmonics.
Adding harmonics is distortion. It may not sound as
such if the harmonics you add were already present
but it still is distortion.
You use a harmonics generator, cut the fundamental,
and add in odd ordered
harmonics, with each successice odd harmonic going in opposite directions.
What's the point of the 'opposite directions' (whatever
it means) ?
Ciao,
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
O tu, che porte, correndo si ?
E guerra e morte !
12 Sep
12 Sep
1:49 a.m.
New subject: [LAU] Exciter / Enhancer Plugin [WAS:] Linux-audio-user Digest , Vol 19, Issue 9
Back on Thursday 11 September 2008, Fons Adriaensen was like:
The magnitude can be positive or negative. It really doesn't matter which way
you go, you get a similar effect. But each successive odd harmonic needs to
be in the opposite direction in order for them to build upon one another.
Otherwise they begin to cancel each other out.
For instance you can have the first, fifth, and ninth be positive while the
third and seventh are negative. Or vice versa. But I never use anything past
the third harmonic. Anything above the third sounds way to harsh and gritty
to me.
If you open the jack-rack file I included, you can take a look at the
harmonics settings I always use. I push the first harmonic all the way
negative and the third at 75% positive. I don't like to push the third any
higher than that or it starts sounding abrasive.
-Reuben
On Thu, Sep 11, 2008 at 05:36:26PM -0500, Reuben
Martin wrote:
Well, I mean not the type of distortion people commonly think of such as
guitar distortion modeled after an overdriven tube amp.
Exciter has nothing to do with dynamics.
True.
And not really anything to do with
distortion so much as harmonics.
Adding harmonics is distortion. It may not sound as
such if the harmonics you add were already present
but it still is distortion. You use a harmonics generator, cut the
fundamental, and add in odd
ordered harmonics, with each successice odd harmonic going in opposite
directions.
What's the point of the 'opposite directions' (whatever
it means) ?
6:33 a.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
On Thu, Sep 11, 2008 at 10:45:35PM -0500, Reuben Martin wrote:
Well, I mean not the type of distortion people
commonly think of such as
guitar distortion modeled after an overdriven tube amp.
It still is just distortion.
The magnitude can be positive or negative. It really
doesn't matter which way
you go, you get a similar effect.
Positive or negatve *at what point* ?
Start gnuplot and type
plot [0:6.28] sin(x), sin(3*x)
At 0, both are going positive. At 1.57 one is positive and
the other negative. If you invert the second, they will
be 'in phase' at 1.57.
Simple fact is that you can't compare phases of two signals
that don't have the same frequency. It just depends on where
you look.
But each successive odd harmonic needs to
be in the opposite direction in order for them to build upon one another.
Otherwise they begin to cancel each other out.
Signals of different frequencies cam't ever cancel each other.
So what does all this mean ?
Ciao,
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
O tu, che porte, correndo si ?
E guerra e morte !
3:25 p.m.
New subject: [LAU] Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
Back on Friday 12 September 2008, Fons Adriaensen was like:
I'm talking in reference to the ladspa harmonics generator plugin.
On Thu, Sep 11, 2008 at 10:45:35PM -0500, Reuben
Martin wrote:
The magnitude
can be positive or negative. It really doesn't matter which
way you go, you get a similar effect.
Positive or negatve *at what point* ?
Start gnuplot and type
plot [0:6.28] sin(x), sin(3*x)
At 0, both are going positive. At 1.57 one is positive and
the other negative. If you invert the second, they will
be 'in phase' at 1.57.
Simple fact is that you can't compare phases of two signals
that don't have the same frequency. It just depends on where
you look.
No, but they can seriously mangle one another in an undesirable manner. If
successive odd harmonics are given the same positive or negative magnitude in
the harmonics generator plugin, the exciter effect is more muted and sounds
muffled, whereas if they are pushed in opposite directions of magnitude, each
odd harmonic intensifies the effect of the odd harmonic before it.
But each successive odd harmonic needs to
be in the opposite direction in order for them to build upon one another.
Otherwise they begin to cancel each other out.
Signals of different frequencies cam't ever cancel each other.
So what does all this mean ?
It means that if you run the third and fifth harmonic magnitude both in the
positive or negative direction on the jack rack setup I provided, it's
probably going to sound like poo.
-Reuben
3:40 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
On Fri, Sep 12, 2008 at 12:21:43PM -0500, Reuben Martin wrote:
Mangle ? How ? If the channel following the harmonic generator,
i.e. after the exciter plugin, is linear then this can't happen.
Ciao,
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
O tu, che porte, correndo si ?
E guerra e morte !
Signals of
different frequencies cam't ever cancel each other.
No, but they can seriously mangle one another in an undesirable
manner. 
4:44 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
On Friday 12 September 2008 13:38:48 Fons Adriaensen wrote:
On Fri, Sep 12, 2008 at 12:21:43PM -0500, Reuben
Martin wrote:
Mangle ? How ?
Can't you just listen and see? (I don't know that I could. I may try a bit
later.) You seem to want theory while he seems to be giving hands on answers.
(I would like the theoretical answers myself, but they may not be on the way.
Have you done the practical side and still don't see what he is getting at?)
Signals
of different frequencies cam't ever cancel each other.
No, but they can seriously mangle one another in an undesirable
manner. If the channel following the harmonic generator,
i.e. after the exciter plugin, is linear then this can't happen.
Ciao,
all the best,
drew
4:57 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
On Fri, 12 Sep 2008 14:44:22 -0400
drew Roberts <zotz(a)100jamz.com> wrote:
On Friday 12 September 2008 13:38:48 Fons Adriaensen
wrote:
I think the OP is referring to phase. Starting with sine waves,
depending on which phase each harmonic is, as you add odd harmonics the
resultant (for a given fundamental) can be made to move towards either
a square wave, or a triangle wave. Whereas if you add even harmonics
you move towards a sawtooth wave.
To me, square and triangle waves sound identical at the same RMS
amplitude. However, the triangle shape will overload an amplifier
faster, and noticeably change in character, while a square wave hardly
changes at all until you are into severe clipping.
Obviously the situation is far more complex with 'real' sounds :)
--
Will J Godfrey
http://www.musically.me.uk
On Fri, Sep 12, 2008 at 12:21:43PM -0500, Reuben
Martin wrote:
Mangle ? How ?
Can't you just listen and see? (I don't know that I could. I may try a bit
later.) You seem to want theory while he seems to be giving hands on answers.
(I would like the theoretical answers myself, but they may not be on the way.
Have you done the practical side and still don't see what he is getting at?)
Signals
of different frequencies cam't ever cancel each other.
No, but they can seriously mangle one another in an undesirable
manner. If the channel following the harmonic generator,
i.e. after the exciter plugin, is linear then this can't happen.
Ciao,
all the best,
drew
6:18 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
On Fri, Sep 12, 2008 at 02:44:22PM -0400, drew Roberts wrote:
Can't you just listen and see?
I have listened and I have done the maths.
Wouldn't care to post otherwise.
Ciao,
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
O tu, che porte, correndo si ?
E guerra e morte !
7:43 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
On Friday 12 September 2008 16:16:14 Fons Adriaensen wrote:
On Fri, Sep 12, 2008 at 02:44:22PM -0400, drew Roberts
wrote:
OK, just asking as from the posts it seemed that might be an issue. I don't
know if my ears would tell me even if I listened. Don't think I have the
maths. I haven't done any heavy maths sine I got out of college back in 81.
(Well, perhaps even only semi heavy back then even.)
I will try and make some time to listen and see what my ears say.
Can't you just listen and see?
I have listened and I have done the maths.
Wouldn't care to post otherwise.
Ciao,
all the best,
drew
8:04 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
On Fri, Sep 12, 2008 at 05:43:12PM -0400, drew Roberts wrote:
I will try and make some time to listen and see what
my ears say.
I don't yet have the complete picture (which is why I
keep on pushing) but one thing that's quite clear is that
this 'alternating polarity' thing may be much more related
to how the Harmonic Generator plugin works than to anything
essential to the 'exciter' effect.
The actual harmonic levels that are generated are
*not* independent as the interface would suggest,
and the interaction between them depends on polarity.
But that's quite different from harmonics 'cancelling'
or 'mangling' each other on their own - no such things
\happen, it's the plugin behaving in a much more complez
way than one would expect.
Ciao,
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
O tu, che porte, correndo si ?
E guerra e morte !
9:21 p.m.
New subject: [LAU] Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
Back on Friday 12 September 2008, Fons Adriaensen was like:
On Fri, Sep 12, 2008 at 05:43:12PM -0400, drew Roberts
wrote:
I've never been speaking about this in terms of theory or math. Quite honestly
I've never really looked into that aspect of it. At the time I created it the
jack rack preset, I just wanted an exciter, I did a little reading on what
type of dsp processing elements are involved, and just messed with different
setups until I got something I liked.
When I say "canceling out" or other terms, please understand I'm not
speaking
literal physics and math. I'm talking about what I hear. And in the end, what
I hear is all that matters to me. I'm simply trying to say that in my messing
around, I found that if I set the third and fifth harmonic both in the
positive or negative direction on the harmonics generator, it would start to
cancel out (i.e. negatively influence) the desired _effect_ of the exciter.
If you are truly that into the math side of it, the source for those plugins
is always available for you to pull apart and see for yourself the
innerworkings and algorithms used.
-Reuben
I will try and make some time to listen and see
what my ears say.
I don't yet have the complete picture (which is why I
keep on pushing) but one thing that's quite clear is that
this 'alternating polarity' thing may be much more related
to how the Harmonic Generator plugin works than to anything
essential to the 'exciter' effect.
The actual harmonic levels that are generated are
*not* independent as the interface would suggest,
and the interaction between them depends on polarity.
But that's quite different from harmonics 'cancelling'
or 'mangling' each other on their own - no such things
\happen, it's the plugin behaving in a much more complez
way than one would expect.
22 Sep
22 Sep
5:54 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
On Fri, Sep 12, 2008 at 06:17:38PM -0500, Reuben Martin wrote:
If you are truly that into the math side of it, the
source for those plugins
is always available for you to pull apart and see for yourself the
innerworkings and algorithms used.
I did some measurements on a real (hardware) Aural Exciter.
Whatever it does is *very* different from what the harmonic
generator plugin is doing.
- Almost all harmonics up to at least the 15th are present.
The first few (2,3,4) have almost the same level, above
that levels go down gradually, with a clear dip at the
seventh.
- The relative (to the fundamental) level of the harmonics
stays more or less the same for a wide range of input
levels. This is very different from any simple form of
harmonic generator, where the level of the Nth harmonic
would be roughly proportional to the Nth power of the
input level.
Ciao,
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
Wie der Mond heute Nacht aussieht !
Ist es nicht ein seltsames Bild ?
6:01 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
On Mon, 22 Sep 2008 21:51:27 +0200
Fons Adriaensen <fons(a)kokkinizita.net> wrote:
I did some measurements on a real (hardware) Aural
Exciter.
Whatever it does is *very* different from what the harmonic
generator plugin is doing.
- Almost all harmonics up to at least the 15th are present.
The first few (2,3,4) have almost the same level, above
that levels go down gradually, with a clear dip at the
seventh.
- The relative (to the fundamental) level of the harmonics
stays more or less the same for a wide range of input
levels. This is very different from any simple form of
harmonic generator, where the level of the Nth harmonic
would be roughly proportional to the Nth power of the
input level.
Ciao,
Interesting piece of research there. Not surprised about the 7th
harmonic. I believe it is reckoned to be the most dissonant
and unpleasant sounding.
--
Will J Godfrey
http://www.musically.me.uk
8:51 p.m.
New subject: [LAU] Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
Back on Monday 22 September 2008, Fons Adriaensen was like:
On Fri, Sep 12, 2008 at 06:17:38PM -0500, Reuben
Martin wrote:
I have an Aphex 104 myself, and have been curious in how it works. My hack
using the simple harmonics generator sounds nowhere near as smooth. It
generally does "ok" for live recorded audio, but it doesn't sound very
smooth
on snyth generated sources. And it is nowhere near what I get with the Aphex
unit.
I find it odd that the harmonics levels stay at the same level reguardless of
the input level. Very interesting.
-Reuben
If you are truly that into the math side of it,
the source for those
plugins is always available for you to pull apart and see for yourself
the innerworkings and algorithms used.
I did some measurements on a real (hardware) Aural Exciter.
Whatever it does is *very* different from what the harmonic
generator plugin is doing.
- Almost all harmonics up to at least the 15th are present.
The first few (2,3,4) have almost the same level, above
that levels go down gradually, with a clear dip at the
seventh.
- The relative (to the fundamental) level of the harmonics
stays more or less the same for a wide range of input
levels. This is very different from any simple form of
harmonic generator, where the level of the Nth harmonic
would be roughly proportional to the Nth power of the
input level.
10:01 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
On Mon, Sep 22, 2008 at 05:47:23PM -0500, Reuben Martin wrote:
I find it odd that the harmonics levels stay at the
same level reguardless of
the input level. Very interesting.
Yes, it must be some rather clever circuit doing that.
My guess (but nothing more) ATM is that they generate
a short pulse that is used to gate part of the original
waveform, then use the 'frequency dependent phase' i.e.
allpass filters to hide the impulsive waveform.
Ciao,
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
Wie der Mond heute Nacht aussieht !
Ist es nicht ein seltsames Bild ?
23 Sep
23 Sep
9:43 p.m.
New subject: [LAU] Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
Back on Monday 22 September 2008, Fons Adriaensen was like:
On Mon, Sep 22, 2008 at 05:47:23PM -0500, Reuben
Martin wrote:
Would the pulse always be the same, or do you think the original waveform
would influence the pulse in any way? I guess if you were using a pulse, it
would give a lot more control over the "texture" of the harmonics produced.
-Reuben
I find it odd that the harmonics levels stay at
the same level
reguardless of the input level. Very interesting.
Yes, it must be some rather clever circuit doing that.
My guess (but nothing more) ATM is that they generate
a short pulse that is used to gate part of the original
waveform, then use the 'frequency dependent phase' i.e.
allpass filters to hide the impulsive waveform.
24 Sep
24 Sep
7:48 a.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user?Digest , Vol 19, Issue 9
it isn't exactly a reply to this renewed thread about the subject of the
Exciter, but in the older thread someone asked to give an example of a
good-sounding exciter. The one that does a great job is the one in Reaper, a
windows program that runs rather well under wine.
I'd prefer working with Ardour and a ladspa version of an exciter as this
program gives no xruns at all (Reaper does). And of course because i think
an exciter should be 'normal' in the Linux audio world.
((Me i cannot make one, i'm not a programmer. But i think Linux shouldn't be
there just for programmers but for users also.))
Menno
-----
http://www.jamendo.com/de/album/6789/
http://www.jamendo.com/en/album/7428/
--
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12 Sep
12 Sep
2:03 a.m.
New subject: [LAU] Exciter / Enhancer Plugin [WAS:] Linux-audio-user Digest , Vol 19, Issue 9
Back on Thursday 11 September 2008, Fons Adriaensen was like:
Ack.. I just realized in the last message I sent I was saying I only used the
first and third and that anything above that was too harsh. Major TYPO!!
The first is the fundamental. What I meant is I use the _third_ and the
_fifth_ and anything above the _fifth_ is too harsh.
I have the third at 100% negative and the fifth at 75% positive (NOT the first
and third)
Anyway, the jack-rack setup is correct though. :)
-Reuben
You use a harmonics generator, cut the
fundamental, and add in odd
ordered harmonics, with each successice odd harmonic going in opposite
directions.
What's the point of the 'opposite directions' (whatever
it means) ?
3:23 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user Digest, Vol 19, Issue 9
2008/9/12 Reuben Martin <reuben.m(a)gmail.com>om>:
Back on Thursday 11 September 2008, Emanuel Rumpf was
like:
Thank you Reuben
Now where I tried your rack-rack file, I better understand the Exciter.
Is it a minor or mayor third?
Does one need to know the key / tonality, for adding harmonics ?
-Emanuel
2008/9/10 Fons Adriaensen
<fons(a)kokkinizita.net>et>:
Exciter has nothing to do with dynamics. And not really anything to do with
distortion so much as harmonics.
You use a harmonics generator, cut the fundamental, and add in odd ordered
harmonics, with each successice odd harmonic going in opposite directions.
The lower order harmonics are not very noticeable, but very smooth. The
higher order harmonics are much more noticeable, but very abrasive sounding.
I generally use all of the first, and about half of the third.
It goes:
original signal => high pass filter => harmonics generator => attenuator
(variable depending on how much you want to add in) => mix back in with
original signal.
Here's a jack-rack file demonstrating it. Route your source into the
jack-rack, and then direct jack-rack's output to the same destination as your
source. Change levels on the "simple amplifier" to adjust how much you need
added back in.
You need the proper ladspa plugins installed for this...
On Wed, Sep 10, 2008 at 01:01:58PM +0200, Martin
Horn wrote:
Someone wrote a kind of tutorial some time ago:
http://ardour.org/node/405
Would be nice to have this as jack-rack file or in rackarrack.
exciter : audio-signal => highpass
=> dissortion => add to audio-signal
enhancer: audio-signal => (different) bandpass filters => dissortion
=> add to audio-signal
(so described in wikipedia) I don't know if such a thing exists for the
linux audio world, but to
get the effect of an exciter you basically need multiband dynamics. That
is a compressor/ expander that works in multiple frequency bands which
are separated by crossovers.
That would be more a 'compellor' than an exciter.
Easy to confuse, both are originally from Aphex. 
4:43 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user Digest, Vol 19, Issue 9
Am Freitag 12 September 2008 schrieb Emanuel Rumpf:
Thank you Reuben
Now where I tried your rack-rack file, I better understand the Exciter.
Is it a minor or mayor third?
Does one need to know the key / tonality, for adding harmonics ?
No, it's not a third as in musical interval, it's the third harmonic (overtone)
of the fundamental ("sounding" frequency)...
-Emanuel
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Edgar
6:13 p.m.
New subject: Exciter / Enhancer Plugin [WAS:] Linux-audio-user Digest, Vol 19, Issue 9
2008/9/12 Edgar Aichinger <edogawa(a)aon.at>at>:
Am Freitag 12 September 2008 schrieb Emanuel Rumpf:
OK
Thank you Edgar.
Thank you Reuben
Now where I tried your rack-rack file, I better understand the Exciter.
Is it a minor or mayor third?
Does one need to know the key / tonality, for adding harmonics ?
No, it's not a third as in musical interval, it's the third harmonic (overtone)
of the fundamental ("sounding" frequency)...
5716
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22 comments
7 participants
participants (7)
-
drew Roberts -
Edgar Aichinger -
Emanuel Rumpf -
Folderol -
Fons Adriaensen -
menno -
Reuben Martin