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 » Clavia Nord Modular » Nord Modular G2 Discussion
Was I supposed to know delay lines are only 16 bits wide?
Post new topic   Reply to topic Moderators: Nord Modular Editors
Page 1 of 1 [24 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
LLR3



Joined: Sep 10, 2004
Posts: 41
Location: Helsinki Finland

PostPosted: Sun Jan 16, 2005 7:25 pm    Post subject: Was I supposed to know delay lines are only 16 bits wide? Reply with quote  Mark this post and the followings unread

Does it say somewhere in the manual that the signal resolution for the delay modules (on G2) should be less than the normal 24 bits?

I was trying to make a signal packer in order to turn one 96 kHz 24-bit audio delay line into two 48 kHz 16-bit audio and sixteen 6 kHz 8-bit control signals (just to waste some spare DSP cycles of course!), but unfortunately I ran into the fact that the delay lines on G2 are only 16 bits wide...

Well, maybe you already knew all this, but in case you didn´t, you can try it yourself by attenuating a clock pulse signal so that it´s just barely strong enough to trigger something (ANYTHING above zero equals to condition true on G2 logic operations). Next try putting a delay module in between the attenuated clock signal and the trigger destination. Now, try re-amplifying the clock signal until it becomes visible on the trigger led again. And then count the bits!

I´ve yet to try the same on G1. (Though I´m quite sure it couldn´t possibly have gone unnoticed this long!)

*Llare
Back to top
View user's profile Send private message
Chet



Joined: Nov 19, 2004
Posts: 231
Location: Lititz,PA,USA
Audio files: 7
G2 patch files: 35

PostPosted: Mon Jan 17, 2005 7:01 pm    Post subject: Reply with quote  Mark this post and the followings unread

That's an interesting observation.

I've noticed on percussive Karplus-Strong patches (which use delay lines as tuned resonators) that there's some really nasty harmonic distortion audible as the sound dies away. I've never been able to figure out why. 16-bit resolution would explain it.

I think the G1 has 24-bit resolution on the delays, because I don't hear that distortion on my G1 patches. It was one of the first things I noticed when I began trying to copy some G1 patches to the G2.

Bummer.
Back to top
View user's profile Send private message
mosc
Site Admin


Joined: Jan 31, 2003
Posts: 18019
Location: Allentown, PA
Audio files: 166
G2 patch files: 60

PostPosted: Mon Jan 17, 2005 8:08 pm    Post subject: Reply with quote  Mark this post and the followings unread

If this is indeed the case, then maybe that is a good item for the Wish List, a button on the delay modules to put them into 24 bit mode. It will give you less time delay, but in some cases it may be worth the tradeoff, eh?
_________________
--Howard
my music and other stuff
Back to top
View user's profile Send private message Send e-mail Visit poster's website AIM Address
cebec



Joined: Apr 19, 2004
Posts: 1093
Location: Virginia
Audio files: 3
G2 patch files: 31

PostPosted: Mon Jan 17, 2005 8:20 pm    Post subject: Reply with quote  Mark this post and the followings unread

oh yeah, let's make this a wish list item... i tend to use short delays on the G2, anyway, and leave any longer delay/reverb duties for native or outboard processing...

hopefully it's possible!
Back to top
View user's profile Send private message
LLR3



Joined: Sep 10, 2004
Posts: 41
Location: Helsinki Finland

PostPosted: Tue Jan 18, 2005 7:39 am    Post subject: Reply with quote  Mark this post and the followings unread

I think the delay lines should have 24-, 16-, 8-, and 1-bit modes available for highest quality audio, "long play" audio, control and logic signals accordingly.

There should also be an option to use lower sampling rates AND a switch for turning the interpolation on or off.

*Llare
Back to top
View user's profile Send private message
Chet



Joined: Nov 19, 2004
Posts: 231
Location: Lititz,PA,USA
Audio files: 7
G2 patch files: 35

PostPosted: Tue Jan 18, 2005 8:23 am    Post subject: Reply with quote  Mark this post and the followings unread

Perhaps the external RAM is only 16 bits wide.

Even so, it's solvable. The delay module could split the 24-bit signal into two paths, send them through two parallel delays, and then combine them back together again. It would require twice as much RAM, but it could be done.

I'd bet the comb filters work this way, too. I've heard the same distortion on them when the signal level gets low.
Back to top
View user's profile Send private message
cebec



Joined: Apr 19, 2004
Posts: 1093
Location: Virginia
Audio files: 3
G2 patch files: 31

PostPosted: Tue Jan 18, 2005 8:55 am    Post subject: Reply with quote  Mark this post and the followings unread

geez, what else is or could be running with 16 bit depth and why?

Shocked
Back to top
View user's profile Send private message
Kassen
Janitor
Janitor


Joined: Jul 06, 2004
Posts: 7678
Location: The Hague, NL
G2 patch files: 3

PostPosted: Tue Jan 18, 2005 9:32 am    Post subject: Reply with quote  Mark this post and the followings unread

Chet wrote:
Perhaps the external RAM is only 16 bits wide.

Even so, it's solvable. The delay module could split the 24-bit signal into two paths, send them through two parallel delays, and then combine them back together again. It would require twice as much RAM, but it could be done.

I'd bet the comb filters work this way, too. I've heard the same distortion on them when the signal level gets low.


You could already do this. you could put a digitiser set to 16 bits (we have those, right?) in front of it, substract that from the original signal to get the difference between 24 and 16 bits. you could amp that difference up by a large (but known) amount, send it through it´s own delay and later recombine the two delay lines taking care to amp the "difference" signal down again by the same amount you just amped it up with.

I´d be carefull before blaming the manual. The manual walks a thin line between "inviting" and "explaining" and clearly "scaring" should be avoided. The people here can deal with this stuff but don´t forget the average synthesis enthousiast is not looking for little modems to get more out of the busses or whatever it is that this is meant to do in the end.

"modem" modules that do this out of the box would be sorta nice though, i could well imagine those getting a lot of use.....

_________________
Kassen
Back to top
View user's profile Send private message Send e-mail Visit poster's website
cebec



Joined: Apr 19, 2004
Posts: 1093
Location: Virginia
Audio files: 3
G2 patch files: 31

PostPosted: Tue Jan 18, 2005 10:35 am    Post subject: Reply with quote  Mark this post and the followings unread

the digitizer only goes to 12 bits or is 24 bits when OFF
Back to top
View user's profile Send private message
jksuperstar



Joined: Aug 20, 2004
Posts: 2503
Location: Denver
Audio files: 1
G2 patch files: 18

PostPosted: Tue Jan 18, 2005 10:38 am    Post subject: Reply with quote  Mark this post and the followings unread

I also support the idea of smaller bit width delays, such as 8b and 1b. That opens up the system for logic and midi delays, which would help alot with moving things from the audio signal chain to the control signal chains to improve DSP usage.


Just to do the math, how much RAM is hanging off each DSP? 96k * 3 = 288k samples/sec, * 2.7sec = 778kB of RAM. We might be able to calculate if Clavia is intending to use 24bit data in the RAMs, and there is simply a bug in how they juggle 3bytes at a time efficiently through the 2byte wide RAM, or if they really are only using 16bits at a time.
Back to top
View user's profile Send private message Visit poster's website
Kassen
Janitor
Janitor


Joined: Jul 06, 2004
Posts: 7678
Location: The Hague, NL
G2 patch files: 3

PostPosted: Wed Jan 19, 2005 3:33 am    Post subject: Reply with quote  Mark this post and the followings unread

cebec wrote:
the digitizer only goes to 12 bits or is 24 bits when OFF


Blast! so much for that plan. It was a nice idea though....

:¬)

Also a bit strange that the logic delay can´t function as a straight 1 bit delay because if it could we could make our own delays just like we need them with the dac and adc modules.

I suppose we can´t have it all.

_________________
Kassen
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Rob



Joined: Mar 29, 2004
Posts: 580
Location: The Hague/Netherlands/EC
G2 patch files: 109

PostPosted: Wed Jan 19, 2005 5:01 am    Post subject: Re: Was I supposed to know delay lines are only 16 bits wide Reply with quote  Mark this post and the followings unread

Llare wrote:
Does it say somewhere in the manual that the signal resolution for the delay modules (on G2) should be less than the normal 24 bits?

*Llare


A look under the hood reveals that the memory chips used in the G2 are indeed 16 bit wide.

As there are two bits of headroom used on the G2 the delays have an effective resolution of 14 bits.

I always felt that the G2 delay lines reminded me of the good old S900 sampler that has been my companion for so long a time. Now I understand. Smile
Back to top
View user's profile Send private message Send e-mail Visit poster's website
cebec



Joined: Apr 19, 2004
Posts: 1093
Location: Virginia
Audio files: 3
G2 patch files: 31

PostPosted: Wed Jan 19, 2005 9:30 am    Post subject: Reply with quote  Mark this post and the followings unread

What else is 16 bit, then? The G2 manual and Clavia website says the audio signal path is 24 bits... Are they incorrect, then? Apparently, the signal is getting degraded at various points that we are unaware of.
Back to top
View user's profile Send private message
Rob



Joined: Mar 29, 2004
Posts: 580
Location: The Hague/Netherlands/EC
G2 patch files: 109

PostPosted: Wed Jan 19, 2005 10:51 am    Post subject: Reply with quote  Mark this post and the followings unread

cebec wrote:
What else is 16 bit, then? The G2 manual and Clavia website says the audio signal path is 24 bits... Are they incorrect, then? Apparently, the signal is getting degraded at various points that we are unaware of.


All the rest is 24 bit. Processing like feedback and filtering within the delay modules is also 24 bit. Its only the chips themselves that are 16 bit, so whatever has to temporarily stored in the external ram memory is reduced to 16 bits width.
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Chet



Joined: Nov 19, 2004
Posts: 231
Location: Lititz,PA,USA
Audio files: 7
G2 patch files: 35

PostPosted: Wed Jan 19, 2005 1:22 pm    Post subject: Reply with quote  Mark this post and the followings unread

Would the delay lines in the comb filters be 16 bits, too? I think I hear the same artifacts on them when I use low signal levels.
Back to top
View user's profile Send private message
Kassen
Janitor
Janitor


Joined: Jul 06, 2004
Posts: 7678
Location: The Hague, NL
G2 patch files: 3

PostPosted: Wed Jan 19, 2005 3:21 pm    Post subject: Re: Was I supposed to know delay lines are only 16 bits wide Reply with quote  Mark this post and the followings unread

Rob wrote:

As there are two bits of headroom used on the G2 the delays have an effective resolution of 14 bits.


Could you go into a little more depth there? what good is headroom if you don´t get to use it for accidental volume spikes? That doesn´t realy sound like "headroom" to me, more like "throwing away two bits". Are those used when the delayline is modulated, perhaps? Is that strategy realy preferable to sensible use of gain?

This does sound a little strange to me, 16 bits isn´t that much if there´s going to be feedback and heaven knows what other stuff, going back to 14 is getting dangerously close to the edge... 24 and 14 only have a factor "2" in common so don´t those 2 spare bits lead to a lot of extra resampling for internal processing?

I´m not so much being critical of the design as I´m wondering what would cause people to take that desision.

_________________
Kassen
Back to top
View user's profile Send private message Send e-mail Visit poster's website
ian-s



Joined: Apr 01, 2004
Posts: 2665
Location: Auckland, New Zealand
Audio files: 42
G2 patch files: 626

PostPosted: Wed Jan 19, 2005 5:47 pm    Post subject: Reply with quote  Mark this post and the followings unread

The missing 8 bits are the LSB's, so a signal with a peak of +-64 (unity) is represented by only 14 bits. Scale the signal by 4 and all 16 bits are used but you are on the threshold of clipping.

This is a bit disappointing but I can't say I would have known if it hadn't been pointed out.
Back to top
View user's profile Send private message
Kassen
Janitor
Janitor


Joined: Jul 06, 2004
Posts: 7678
Location: The Hague, NL
G2 patch files: 3

PostPosted: Wed Jan 19, 2005 5:59 pm    Post subject: Reply with quote  Mark this post and the followings unread

Ah! check, that´s not as bad as I imagined it could be then.

Thanks for that. I probably wouldn´t have noticed either but I hear you can get realy clever if you ask enough questions. "curiocity makes the cat" as the old Russian saying goes.

;¬)

_________________
Kassen
Back to top
View user's profile Send private message Send e-mail Visit poster's website
mosc
Site Admin


Joined: Jan 31, 2003
Posts: 18019
Location: Allentown, PA
Audio files: 166
G2 patch files: 60

PostPosted: Wed Jan 19, 2005 6:58 pm    Post subject: Reply with quote  Mark this post and the followings unread

Kassen wrote:
"curiocity makes the cat" as the old Russian saying goes.
;¬)


Now I understand why we had the cold war. Here in the USA, the experssion is "curiosity KILLED the cat." Shocked

_________________
--Howard
my music and other stuff
Back to top
View user's profile Send private message Send e-mail Visit poster's website AIM Address
jksuperstar



Joined: Aug 20, 2004
Posts: 2503
Location: Denver
Audio files: 1
G2 patch files: 18

PostPosted: Thu Jan 20, 2005 8:19 am    Post subject: Reply with quote  Mark this post and the followings unread

I'm still not convinced that because the memory is 16bit wide, that the delay *has* to be 16bits wide.

Rob, can you confirm this was Clavia's intent (or mistake)?
Back to top
View user's profile Send private message Visit poster's website
Kassen
Janitor
Janitor


Joined: Jul 06, 2004
Posts: 7678
Location: The Hague, NL
G2 patch files: 3

PostPosted: Thu Jan 20, 2005 11:49 am    Post subject: Reply with quote  Mark this post and the followings unread

mosc wrote:
Kassen wrote:
"curiocity makes the cat" as the old Russian saying goes.
;¬)


Now I understand why we had the cold war. Here in the USA, the experssion is "curiosity KILLED the cat." Shocked


That must be founded on a translation error. When you think about it it makes no sense that way. (well, perhaps with the dmca it does in the u.s.....)

I´m teasing you, by the way, I don´t realy know a Russian saying that goes like that. All of the eastblock sayings I ever got explained to me went along the lines of "the bottle will break" or "the cow is going to die" and meant that thing might get worse. When i observed this they seemed quite puzzeled as none of it sounded depressing or negative to them nor did it all sound the same.

_________________
Kassen
Back to top
View user's profile Send private message Send e-mail Visit poster's website
davep



Joined: Jul 05, 2004
Posts: 467
Location: Oakland, CA
Audio files: 10
G2 patch files: 73

PostPosted: Thu Jan 20, 2005 12:13 pm    Post subject: (OT - funny translations) Reply with quote  Mark this post and the followings unread

That must be founded on a translation error. When you think about it it makes no sense that way. (well, perhaps with the dmca it does in the u.s.....)

I love funny translations! When I was in China recently I was in a park that had about 20 large signs - not painted on wood, but actually CARVED in STONE that said: "We can't stand the sight of mattress fragrant grass".

I assume it was supposed to be telling me to stay off the grass. I think the funniest part is the fact that someone went to the trouble of carving 20 signs into large rocks without checking the translation.

BTW, my favorite 'colorful' saying is from Romania and translates into: "A dog could walk between her legs with a stick in his mouth".

_________________
Dave Peck
Back to top
View user's profile Send private message
Rob



Joined: Mar 29, 2004
Posts: 580
Location: The Hague/Netherlands/EC
G2 patch files: 109

PostPosted: Fri Jan 21, 2005 1:34 pm    Post subject: Reply with quote  Mark this post and the followings unread

jksuperstar wrote:
I'm still not convinced that because the memory is 16bit wide, that the delay *has* to be 16bits wide.

Rob, can you confirm this was Clavia's intent (or mistake)?


Well, if someone is visiting the NAMM right now they could ask a Clavia guy.

Anyway, the chips are definitely 16 bit. Still, Clavia could use two words for one sample and so run delay lines at 32 bit at the cost of a few cycles.

My guess is that the comb filter and the stringosc both use the ram and so run at 16 bit. The clocked delays don't as apparently they do use the full 24 bit.
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Rob



Joined: Mar 29, 2004
Posts: 580
Location: The Hague/Netherlands/EC
G2 patch files: 109

PostPosted: Fri Jan 21, 2005 1:38 pm    Post subject: Reply with quote  Mark this post and the followings unread

mosc wrote:
Kassen wrote:
"curiocity makes the cat" as the old Russian saying goes.
;¬)


Now I understand why we had the cold war. Here in the USA, the experssion is "curiosity KILLED the cat." Shocked


Since magnetrons over here its 'curiosity FRIED the cat'. As after all its just a matter of perspective and what is not in the manual. Wink
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic Moderators: Nord Modular Editors
Page 1 of 1 [24 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » Clavia Nord Modular » Nord Modular G2 Discussion
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


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