The Logic Off Topic list

I don't have a clue, but the Apogee Rosetta has a 'soft limit' which I 
believe converts the linear signal to a log signal above a threshhold. 
Mu, is often used for the mean or average by the way.

>What I know of it is that it acts as a normal compressor reducing the 
>output level above a given threshold by a given ration, but if the input 
>level should rise above another given threshold (call it Mu for 
>convenience, which is higher than the Threshold level...) then the input 
>will be passed through as an exponential in excess of the Mu level, ie. no 
>big discontinuity when the Mu level is reached.
>
>Is this correct? Are there any other factors involved? Can anyone point me 
>to where I might find info online or elsewhere? I need to know this as I 
>am trying to write a Variable Mu VST compressor.

> I don't have a clue, but the Apogee Rosetta has a 'soft limit' which I
> believe converts the linear signal to a log signal above a threshhold.
> Mu, is often used for the mean or average by the way.
>

Thanks Greg,
yeah, I use the log signal trick with some wave shapers (read as :
overdrive ) and it works real nice!

I think Variable Mu may be a misnomer - possibly? - when  I have some head
space I'll try and see if variable average makes sense in this context, ta.

p.s. Greg winsomness suits you! :) but for Debs sake would you let up? I
think we all get the point by now :|

cheers
--
Mark Lennox
Consultant

ENDUSER
Guinness Enterprise Centre
Taylor's Lane
Dublin 8
Ireland
--
e-mail : mark@...
phone  : (+353 1) 4100 665
direct : (+353 1) 4100 707
fax : (+353 1) 4100 985
web    : http://www.enduser.ie
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>p.s. Greg winsomness suits you! :) but for Debs sake would you let up? I
>think we all get the point by now :|

I'm not going to say anything more about Debs one way or the other. She 
actually seems to be a nice young girl. However, I think there was a 
lesson for everyone about the subtle nature of gender discrimination - 
not just jokes about 'logic being like a beautiful woman' for which I was 
moderated and scorned, but in these simple things. I hope Deb gave some 
thought to her study habits, her preconcieved ideas, and her cloying 
attitude which reinforces stereotypes - perhaps more than she was looking 
to find out. I'm done. 

When's the next big argument brewing? 

Love to everyone

XXOOOO

Mu is a term for a type of gain in a tube amp stage.
Basically, since most tube amps (in audio) have been class-A (at least until
the power stage), it controls the slew rate of one polarity - the other one
being fixed by the resistor in the circuit.  What does that mean for the
average bear?  Level of second harmonic distortion (as balanced against
third).

> From: GAmoore@...
> Reply-To: logic-ot@yahoogroups.com
> Date: Mon, 26 Nov 2001 12:21:31 EST
> To: logic-ot@yahoogroups.com
> Subject: Re:  [L-OT] Variable Mu COmpressor - explanation anyone?
> 
> I don't have a clue, but the Apogee Rosetta has a 'soft limit' which I
> believe converts the linear signal to a log signal above a threshhold.
> Mu, is often used for the mean or average by the way.
> 
>> What I know of it is that it acts as a normal compressor reducing the
>> output level above a given threshold by a given ration, but if the input
>> level should rise above another given threshold (call it Mu for
>> convenience, which is higher than the Threshold level...) then the input
>> will be passed through as an exponential in excess of the Mu level, ie. no
>> big discontinuity when the Mu level is reached.
>> 
>> Is this correct? Are there any other factors involved? Can anyone point me
>> to where I might find info online or elsewhere? I need to know this as I
>> am trying to write a Variable Mu VST compressor.
> 
> 
> 
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>

Kool,

you are a font of knowledge and wit! Thanks for the pointers, look like they
are exactly what I want.

I realise the compressor I'm writing is a little strange, I'll have to make
up my own name for it. Or hey! what about a competition, like when Blue
Peter named their pets!

So come on children, send in those names!

:)

ta
--
Mark Lennox
Consultant

ENDUSER
Guinness Enterprise Centre
Taylor's Lane
Dublin 8
Ireland
--
e-mail : mark@...
phone  : (+353 1) 4100 665
direct : (+353 1) 4100 707
fax : (+353 1) 4100 985
web    : http://www.enduser.ie
--
----- Original Message -----
From: "Kool Musick" <koolmusick@...>
To: <logic-ot@yahoogroups.com>
Sent: Wednesday, November 28, 2001 2:36 AM
Subject: Re: [L-OT] Variable Mu COmpressor - explanation anyone?


> Mark Lennox wrote:
>
> >I need someone to set me straight on Variable Mu compressors at a
detailed
> >level.
> <snip>
> >Can anyone point me to where I might find info online or elsewhere? I
need
> >to know this as I am trying to write a Variable Mu VST compressor.
>
> Well ... I don't know if anything I say will "set you straight", but I'm
> willing to try to offer you the very little I know if it's any good.
>
> As marc lindahl said, mu is basically just the term used by the
tube-loving
> audio fraternity for 'gain'. The term 'Variable Mu Compressor' became
> famous because that's basically what Manley called their gear. The more
> general, and so probably more accurate, name is "variable gain compressor"
> or "vari-gain compressor". However, the Manley stuff is so famous that
> everyone pretty much thinks that the name they trademarked for their
> compressor is what all such compressors are called. Bit like Polaroid or
> Biro, I guess.
>
> There's five basic kinds of gain reduction used by compressors:
> 1) Optical isolators using LED's, photoelectric cells and the like
> 2) FET's (field-effect-transistors) which use transistors
> 3) VCA's (voltage controlled amplifier)
> 4) Digital compressors (e.g. plug-ins)
> 5) Variable gains
>
> Variable gain is pretty much a catch all in that it covers those
> compressors that include specific circuits incorporating specific
> electrical/electronic components that do not belong to the other
categories.
>
> If you're building a VST compressor then YOU probably don't need to know
> any of this, but for those who want the gen on compression here's a
15-page
> article which should set them straight:
>
http://www.digitalprosound.com/cgi-bin/getframeletter.cgi?/2001/02_feb/featu
res/big_squeeze/big_squeeze1.htm
>
> And ... since you're trying to build one then here's a longish pdf file
> which will probably really fascinate YOU but pretty much give everyone
else
> insomnia!!
> http://www.geofex.com/PCB_layouts/d&rpub.pdf
>
> Here's the real McCoy ... the Manley site where there's lots of stuff
about
> that really famous Manley Stereo Variable Mu Compressor. Yippeeeee!!
> http://www.manleylabs.com/containerpages/mu99.html
> Long time since I looked at it and it might well be where I got some of
the
> links I've given above. If so, sorry for the repetition.
>
> Then finally (BIG YAWN) here's some graphs taken direct off the Manley
site

> that tells you what you really want to know 'cause it's some really dinky
> actual real life graphs showing relative gains 'n' stuff. Enjoy. And ...
> see how I really enjoyed keeping the good stuff until close to the end!!!
> http://www.manleylabs.com/PDF/PRO_Manuals/Var%20Mu/gr%20chart.pdf
>
> Hope I've helped you some.
> Helpful is what I generally try to be, to be honest ... but ... best not
> say any more, ay??!!!!!!
>
> Kool Musick
> Keep Musick Kool
>
>
> _________________________________________________________
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> Get your free @... address at http://mail.yahoo.com
>
>
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>

Mark Lennox wrote:

>Thanks for the pointers, look like they
>are exactly what I want.
I'm very glad they were helpful to you. Sorry for the delay in getting them 
to you. There were .... Reasons.

>I realise the compressor I'm writing is a little strange,
Errr .... while you're in a good mood and drunk with excitement and all 
that ....
would this be a good moment to ask for a freebie of the finished product? 
Not trying to take advantage or anything!!!!

>I'll have to make
>up my own name for it. Or hey! what about a competition, like when Blue
>Peter named their pets!
>So come on children, send in those names!

Yeah ............ I got a few:

The Kool Kompressor

The Kool Komp

The Kool Mu Kompressor
(Kool Mu-sick, geddit!!)

The Kool Mu Komp


Oh ... the possibilities


Wheeeee!!! This IS exciting!!!!!!! I may be about to be immortalized!!!!!!

Kool Musick
Keep Musick Kool


_________________________________________________________
Do You Yahoo!?
Get your free @... address at http://mail.yahoo.com

>I realise the compressor I'm writing is a little strange, I'll have to make
>up my own name for it. Or hey! what about a competition, like when Blue
>Peter named their pets!

How about a compressor connected to a filter or affect so that the more 
compresor compresses, the more opens the filter, but otherwise its left 
alone.

GAMoore wrote:
> How about a compressor connected to a filter or affect so that the more
> compresor compresses, the more opens the filter, but otherwise its left
> alone.
>

thats an envelope filter (sorta..), also in the works :)

I did have an idea for a distortion effect that would heavily distort low
level signals but reduce the distortion for higher level signals, should
sound like some weird compresser effect...

I'm sure I asked the question before, but what class of effect are most
people looking for? tremelos, chorus, flanger, delay, distortion, filters
etc.  or what??


cheers
--
Mark Lennox
Consultant

ENDUSER
Guinness Enterprise Centre
Taylor's Lane
Dublin 8
Ireland
--
e-mail : mark@...
phone  : (+353 1) 4100 665
direct : (+353 1) 4100 707
fax : (+353 1) 4100 985
web    : http://www.enduser.ie
--

Hi Mark,

> I did have an idea for a distortion effect that would heavily distort low
> level signals but reduce the distortion for higher level signals, should
> sound like some weird compresser effect...

The 3rd Ohmforce plugin does frequency dependent distortion and it's 
lovely imo. Level dependent distortion doesn't exist yet afaik.

> I'm sure I asked the question before, but what class of effect are most
> people looking for? tremelos, chorus, flanger, delay, distortion, filters
> etc.  or what??

I personally love phasers and can't have enough phaser algorithms, but 
I've heard several people are looking for things like AmpFarm  and 
guitar stuff... (don't ask me what exactly, I'm not familiar with it).

Good filters are also welcome. I LOVE the Ohmforce filter and I also 
love Emagic's Autofilter, but another very good multiband filter would 
be nice. Mind: a "good" one... it's not easy to do a good one, I think 
(there are many crappy ones on the market imo). And now that I think of 
it: a DUAL multiband filter as separate plugin doesn't exist yet afaik. 
Something that we can switch in serial or parallel mode. I'd die to get 
one of those... IF it sounds good, that is!

I wouldn't do a delay if I were you. I know other companies who're 
working on delays now, so better wait and see what the 
"competition/colleagues" release.

Bye,
Joeri

-- 
Belway Productions

Dolby made a box like that a few years ago - a spectral compressor they
called it I think.

> From: GAmoore@...
> 
> How about a compressor connected to a filter or affect so that the more
> compresor compresses, the more opens the filter, but otherwise its left
> alone.

> From: "Mark at Enduser" <mark@...>
> 
> I'm sure I asked the question before, but what class of effect are most
> people looking for? tremelos, chorus, flanger, delay, distortion, filters
> etc.  or what??


Naahhh.. there's plenty of those... how about something "off the map"??

>I'm sure I asked the question before, but what class of effect are most
>people looking for? tremelos, chorus, flanger, delay, distortion, filters
>etc.  or what??

Actually there are a lot of these already. I wonder why we need any more 
of the same thing. What I would like is something different and new. I 
like Frohmage - it has quite a range of affects. 

Have you checked out the GRM plugs? Maybe you can do something like that. 
You take an audio region, say a half measure long, you cut it into 16 
slices (32nd notes) - or take a single slice and copy it automatically 16 
times, then you apply affects selectively to each slice. For example, a 
pitch shift down, a low-pass filter to cut the treble, and flange, 
whatever. And then you  have a graph like Hyperdraw, where you define how 
these will take place. 

This would be different and give some cool affects real fast.

>  > I did have an idea for a distortion effect that would heavily distort low
>>  level signals but reduce the distortion for higher level signals, should
>>  sound like some weird compresser effect...

Low bit depth does this.  Actually there used to be an audiosuite 
plug-in that could do this it was Chip Burwell's Power Transformer. 
I think you can do something like it with Cyanide too which is a 
little like PowerTransformer.  I really wish that Chip Burwell would 
come out of hiding and write a VST version of power transformer.  It 
was extremely simple and extremely cool.

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