electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
 Forum index » DIY Hardware and Software
multi-channel panning
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 1 [17 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
blinky_Palermo



Joined: Feb 07, 2014
Posts: 7
Location: taiwan

PostPosted: Tue Mar 25, 2014 9:19 pm    Post subject: multi-channel panning Reply with quote  Mark this post and the followings unread

hi all -

i was wondering about how to split a single control voltage over several VCAs - i know there are probably a couple of different methods for doing this, but i couldn't find anything about it in the forums. does anyone have any thoughts on this subject?

thanks!
-bp
Back to top
View user's profile Send private message
bubzy



Joined: Oct 27, 2010
Posts: 551
Location: United Kingdom
Audio files: 61

PostPosted: Wed Mar 26, 2014 12:26 am    Post subject: Reply with quote  Mark this post and the followings unread

just some buffers would do it, assuming that you dont want to do anything fancy with the signal

I made a pcb a while ago for a buffer "array"
http://electro-music.com/forum/topic-51273.html

_________________
_Richard_ Smile
Back to top
View user's profile Send private message
fonik



Joined: Jun 07, 2006
Posts: 3756
Location: Germany
Audio files: 23

PostPosted: Wed Mar 26, 2014 6:49 am    Post subject: Reply with quote  Mark this post and the followings unread

a multiple! (just split)
_________________
Posted Image, might have been reduced in size. Click Image to view fullscreen.
cheers,
matthias
____________
fonitronik at
FlickR (pix) / SoundCloud (sounds) / YouTube (vids) / Vimeo (vids) / facebook (news)
Back to top
View user's profile Send private message Send e-mail Visit poster's website
bubzy



Joined: Oct 27, 2010
Posts: 551
Location: United Kingdom
Audio files: 61

PostPosted: Wed Mar 26, 2014 8:33 am    Post subject: Reply with quote  Mark this post and the followings unread

ill make a pcb for splitting now


0-0-0-0-0-0-0-0-0-0-0

there Very Happy

_________________
_Richard_ Smile
Back to top
View user's profile Send private message
blinky_Palermo



Joined: Feb 07, 2014
Posts: 7
Location: taiwan

PostPosted: Wed Mar 26, 2014 1:51 pm    Post subject: Reply with quote  Mark this post and the followings unread

i'm sorry, maybe i wasn't clear.. i'd like to be panning between the different outputs over a single voltage excursion, not turning them all on at the same time..
Back to top
View user's profile Send private message
Blue Hell
Site Admin


Joined: Apr 03, 2004
Posts: 20517
Location: The Netherlands, Enschede
Audio files: 147
G2 patch files: 318

PostPosted: Wed Mar 26, 2014 2:27 pm    Post subject: Reply with quote  Mark this post and the followings unread

You mean like http://www.schneidersladen.de/en/toppobrillo-mixiplexer.html probably ... crossfading (de) multiplexer ... it is not very easy I think as an analog module.

Probably the easiest way would be to use an arduino like thing with a couple of analog outputs to control VCA's with and an analog input to control it from. EDIT: but would bee hard to run at audio rates ...

When done all discrete maybe with one of 'm LED bar driver ICs, but it would have to use PWM then to be able to interpolate between LED outputs, and still a lot of random logic too.

_________________
Jan
Back to top
View user's profile Send private message Visit poster's website
fonik



Joined: Jun 07, 2006
Posts: 3756
Location: Germany
Audio files: 23

PostPosted: Wed Mar 26, 2014 3:09 pm    Post subject: Reply with quote  Mark this post and the followings unread

a scanner, you mean?
_________________
Posted Image, might have been reduced in size. Click Image to view fullscreen.
cheers,
matthias
____________
fonitronik at
FlickR (pix) / SoundCloud (sounds) / YouTube (vids) / Vimeo (vids) / facebook (news)
Back to top
View user's profile Send private message Send e-mail Visit poster's website
blinky_Palermo



Joined: Feb 07, 2014
Posts: 7
Location: taiwan

PostPosted: Wed Mar 26, 2014 3:29 pm    Post subject: Reply with quote  Mark this post and the followings unread

yeah, i've seen some of these scanner designs - but i'm not sure it needs to be that complex, i don't necessarily need to route four different sources to four different outputs. i'm not necessarily concerned with linear interpolation. audio rate would be nice, though. Wink

i feel like there must be some simpler ways to divide a single voltage..
Back to top
View user's profile Send private message
fonik



Joined: Jun 07, 2006
Posts: 3756
Location: Germany
Audio files: 23

PostPosted: Thu Mar 27, 2014 12:50 am    Post subject: Reply with quote  Mark this post and the followings unread

blinky_Palermo wrote:
i feel like there must be some simpler ways to divide a single voltage..

a LED bar driver as blue hell suggested would be a good solution. it comprises several comparators. it would be some inverting circuitry on the outputs needed to control the VCAs, though (you only need the VCAs to be on/off, i guess).

_________________
Posted Image, might have been reduced in size. Click Image to view fullscreen.
cheers,
matthias
____________
fonitronik at
FlickR (pix) / SoundCloud (sounds) / YouTube (vids) / Vimeo (vids) / facebook (news)
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Blue Hell
Site Admin


Joined: Apr 03, 2004
Posts: 20517
Location: The Netherlands, Enschede
Audio files: 147
G2 patch files: 318

PostPosted: Thu Mar 27, 2014 3:07 am    Post subject: Reply with quote  Mark this post and the followings unread

It is the fading bit causing the headache Rolling Eyes
_________________
Jan
Back to top
View user's profile Send private message Visit poster's website
fonik



Joined: Jun 07, 2006
Posts: 3756
Location: Germany
Audio files: 23

PostPosted: Thu Mar 27, 2014 3:16 am    Post subject: Reply with quote  Mark this post and the followings unread

ARs between the comparators and the VCAs? would be far from 'equal power' fading, though.
_________________
Posted Image, might have been reduced in size. Click Image to view fullscreen.
cheers,
matthias
____________
fonitronik at
FlickR (pix) / SoundCloud (sounds) / YouTube (vids) / Vimeo (vids) / facebook (news)

Last edited by fonik on Thu Mar 27, 2014 11:13 am; edited 1 time in total
Back to top
View user's profile Send private message Send e-mail Visit poster's website
blinky_Palermo



Joined: Feb 07, 2014
Posts: 7
Location: taiwan

PostPosted: Thu Mar 27, 2014 8:33 am    Post subject: Reply with quote  Mark this post and the followings unread

thanks for the ideas, everyone!
an LED driver might be a good way to go.. definitely considered the comparator+a/r method also.. i know there are analog multiplexing/demultiplexing ICs out there, has anyone experimented with those?
Back to top
View user's profile Send private message
kkissinger



Joined: Mar 28, 2006
Posts: 1214
Location: Kansas City, Mo USA
Audio files: 29

PostPosted: Thu Mar 27, 2014 9:42 am    Post subject: Reply with quote  Mark this post and the followings unread

Blue Hell wrote:
When done all discrete maybe with one of 'm LED bar driver ICs, but it would have to use PWM then to be able to interpolate between LED outputs, and still a lot of random logic too.


THis is a problem that I've wanted to solve for years -- namely, how to control an array of VCA's with a single CV (i.e., a surround sound system).

The problem is that one wants a VCA to respond to a voltage range. For example, say at <2v>4v the VCA is silent. At 3v the VCA is at max loudness. To effect the cross-fade, you would need to stagger the voltage ranges: 2v to 4v, 3v, to 5v, 4v to 6v... etc.

Consider a scenario with voltage detectors at 1/2 volt intervals (could be accomplished with something similar to the Aries threshold detector switch. Now, consider the possibilities if you sum the input CV with a 2v high-frequency sine wave. This means that for an input CV of 3v, it will sweep from 2v to 4v. The 3v comparator will have the largest duty-cycle and the duty-cycle will decrease farther away from 3v.

Thus, the 2v will have small duty cycle as will the 4v, 2.5 v and 3.5 v approaching 25%, and 3v nearly 50%. Each of these steps can be used to charge a capacitor (really, just a lag circuit) and then each voltage would be summed (check the simple and effective way that a pulse wave is converted to a discreet voltage in the Paia Theremax). It may be possible to sum the square waves and then run convert to a voltage. Will have to work with it.

I am going to check the schematics for the Aries threshold detector switch -- it accomplishes the same thing without the use of a s/h. I may be able to patch something up on my synth to check the theory (even though it will have a coarse resolution).

_________________
-- Kevin
http://kevinkissinger.com
Back to top
View user's profile Send private message Visit poster's website
Blue Hell
Site Admin


Joined: Apr 03, 2004
Posts: 20517
Location: The Netherlands, Enschede
Audio files: 147
G2 patch files: 318

PostPosted: Thu Mar 27, 2014 12:41 pm    Post subject: Reply with quote  Mark this post and the followings unread

Yup Kevin, that was the rough idea I had.

BTW the topobrillo module seems to do it with CMOS switches .. so I guess that adds some wave to the input as well to be able to make interpolation.

_________________
Jan
Back to top
View user's profile Send private message Visit poster's website
wackelpeter



Joined: May 05, 2013
Posts: 43
Location: germany
Audio files: 6

PostPosted: Thu Mar 27, 2014 1:14 pm    Post subject: Reply with quote  Mark this post and the followings unread

first thought about this:

a CV (sine,triangle or ramp from LFO or ADSR) fed into a multilpier (or CV mixer with several outputs) then those CV(s) fed into the input of several S&h Units... those clocked via the different outputs of an 4017 that is fed by another clock... so you get different values of that cv at the S&h Outs and can vary the s&h rate manually... the 4024 as divider could also be a good choice for clocking the s&h's...

all units simple to build and could be used in many different ways...


but it seems as i understood the requested/wanted solution wrong...

cheers bastian
Back to top
View user's profile Send private message
prgdeltablues



Joined: Sep 25, 2006
Posts: 174
Location: UK
Audio files: 11

PostPosted: Fri Mar 28, 2014 8:09 am    Post subject: Reply with quote  Mark this post and the followings unread

This may be completely on the wrong track, but I just happened to be mulling formant filters, and wondered if the CV shaper in Jim Patchell's vocal filter might be of any value in addressing this problem. See:

http://www.noniandjim.com/Jim/synthmodules/vocalfilter.pdf

It looks as if you could set breakpoints such that the output voltage rose linearly up to 3V (say) then fell linearly down to the next breakpoint. Or the output voltagr can be held constant over a range of input voltages. One of these for each VCA? Overlap the ranges, stagger the ranges...

Peter
Back to top
View user's profile Send private message
widdly



Joined: Jun 25, 2007
Posts: 265
Location: singapore
G2 patch files: 2

PostPosted: Thu Apr 24, 2014 2:37 am    Post subject: Reply with quote  Mark this post and the followings unread

I'm not sure I'm following properly but this design is pretty cool...

http://www.musicsynthesizer.com/Corpse/VCEOM.html


Posted Image, might have been reduced in size. Click Image to view fullscreen.

The dither idea is genius. Mixing a fast sawtooth with the CV creates Pwm type switching in the LM3914. Since the "VCA's" are vactrols they smooth this out and create a linear crossfade.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 1 [17 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use