Synth-DIY Yahoo! Groups Archives

Thread

Delay any Delay buying :)

2003-10-31 by Paul Schreiber

Just like I responded to the request for the ARP filter (I hope to have prototypes by mid-Nov), I
am in 'contact' with a potential source for a digital delay and sampler/looper MOTM delay module.
Stay tuned for more info as this progress.

I'm trying to do one with at least 2 CV "parameters" for <$400 (assembled only, as it's all SMT).
I'd like to get $300, but I don't think I can liscensing another design.

So, fell free to start posting "list of desired features". I can't say how flexible I can be in
changing the DSP code.

Paul S.

Re: [motm] Delay any Delay buying :)

2003-10-31 by Robert van der Kamp

On Friday 31 October 2003 18:24, Paul Schreiber wrote:

> Just like I responded to the request for the ARP filter
> (I hope to have prototypes by mid-Nov), I am in 'contact'
> with a potential source for a digital delay and
> sampler/looper MOTM delay module. Stay tuned for more
> info as this progress.

Ohhhh, a MOTM *looper*. :))
I own two Repeaters and a Lex MPX-G2 with 10 secs of delay,
but having this in MOTM format with sounds *very* nice.

Show quoted textHide quoted text

>
> I'm trying to do one with at least 2 CV "parameters" for
> <$400 (assembled only, as it's all SMT). I'd like to get
> $300, but I don't think I can liscensing another design.
>
> So, fell free to start posting "list of desired
> features". I can't say how flexible I can be in changing
> the DSP code.

For a good looper you need aprox 10 secs delay, the more
the better.

You'd need CV feedback conyrol. By reducing the feedback,
you get the chance to 'clean' the loop and make room for
new material to be fed into the loop.

A CV record/play mode switch is needed.

When switching in/out record mode, no clicks/ticks/whatever
should be produced.

No clicks/ticks must be heard when the loop 'returns' to the
start of the buffer, even when a long ambient sound is
recorded.

A lowpass filter for emulating an analog delay is needed,
with CV control. But because we all have filters around,
maybe it is possible to insert a filter into the loop
signal. That takes an DA and DA converter, so the built-in
LPF is probably a better choice.

- Robert

Re: Delay any Delay buying :)

2003-10-31 by cormallen

> So, fell free to start posting "list of desired features". I can't

say how flexible I can be in

Show quoted textHide quoted text

> changing the DSP code.

V/8ve input! Perfect for waveguide type stuff...

Harry

Re: [motm] Delay any Delay buying :)

2003-10-31 by Mike Estee

On Oct 31, 2003, at 9:24 AM, Paul Schreiber wrote:

> Just like I responded to the request for the ARP filter (I hope to
> have prototypes by mid-Nov), I
> am in 'contact' with a potential source for a digital delay and
> sampler/looper MOTM delay module.
> Stay tuned for more info as this progress.

I am very, very happy to hear to this!

> I'm trying to do one with at least 2 CV "parameters" for <$400
> (assembled only, as it's all SMT).
> I'd like to get $300, but I don't think I can liscensing another
> design.

Delay time and feedback would be my vote for delay parameters. Price
sounds fine by me, lower is always better, but 400 doesn't sound too
high.

Show quoted textHide quoted text

> So, fell free to start posting "list of desired features". I can't say
> how flexible I can be in
> changing the DSP code.

I think keeping the feature set to things that make since *within* the
modular signal chain as opposed to pre/post processing is pretty
important. There are plenty of other fx processors to handle those
tasks. It doesn't need a reverb, for example. It also shouldn't try to
replace your guitar looper, there are better tools for that.

Most importantly: This delay must never, ever, ever, ever digitally pop
or clip. Ever. At all. No matter how it's abused.

The feedback should be literal, that is, the final output stage of the
looper should have two outs and two inputs. To do feedback you take one
output, route it back into the CV controlled input and it's
remixed/limited/filtered with the main single. This allows for doing
things to the feedback signal in unusual ways, like passing it through
a '440 on an LFO'd cutoff . There is an ocean of sounds to be made from
screwing around with the feedback before it gets pushed back into the
delay line.

Changes to delay time should not clip. Play with the delay on the
access virus for an example of a very nice delay. Delay time should be
CV controllable, and sync-able. In other words, a re-trigger signal
for the delay. One should be able to sync delay to an LFO or pulse
wave, etc. Fun sampling like effects could be done with this.

There's certainly room for more than one kind of delay in the MOTM line
too ;)

Re: Delay any Delay buying :)

2003-10-31 by rreprobate

--- In motm@yahoogroups.com, Mike Estee <mikest@a...> wrote:

Show quoted textHide quoted text

> The feedback should be literal, that is, the final output stage of the
> looper should have two outs and two inputs.

Love the idea of it just being a delay line with no other features. Patch it into an echo
with whatever other modules you want. I do this all the time. The only drawback is
that it's way lo-fi compared to feedback done in DSP. As long as you could turn the
mix to 100% wet and feedback to 0% I'd be happy.

How about dual synced delay lines with windowing functions for granular effects?
Ow! Who just kicked me?!?!

Max

Re: [motm] Re: Delay any Delay buying :)

2003-10-31 by Mike Estee

On Oct 31, 2003, at 12:07 PM, rreprobate wrote:

Show quoted textHide quoted text

> --- In motm@yahoogroups.com, Mike Estee <mikest@a...> wrote:
>> The feedback should be literal, that is, the final output stage of the
>> looper should have two outs and two inputs.
>
> Love the idea of it just being a delay line with no other features.
> Patch it into an echo
> with whatever other modules you want. I do this all the time. The only
> drawback is
> that it's way lo-fi compared to feedback done in DSP. As long as you
> could turn the
> mix to 100% wet and feedback to 0% I'd be happy.

I would argue that it's not *that* lowfi ^_^, but yeah, you'd get
coloration over time as the delay line loops. Anyway, there are much
better toys for looping. I totally love the idea of just a delay line.
In addition, I very much like the idea of keeping the things analog
does well in the analog domain and the things digital does well in the
digital domain.

For example, I think it's silly to do the filtering with a DSP
algorithm, you end up having to code back all the variances and
imperfections found in a real filter that make them sound good. You'll
get better filtering from any of the 400 series anyway. Same applies
for the mixing. What happens when the feedback overloads? In a digital
algorithm? In a analog circuit? I think those edge conditions are
important.

Time scaling resolution should be high enough to avoid zippering.
Ranges are fine way to overcome this.

Just the thought of a feedback delay line that incorporates a 440 makes
me drool ^_^

ps: has anyone else here played with the evolver? it's a dsp/analog
hybrid.

Re: [motm] Delay any Delay buying :)

2003-10-31 by jhaible

> I'm trying to do one with at least 2 CV "parameters" for <$400 (assembled

only, as it's all SMT).

Show quoted textHide quoted text

> I'd like to get $300, but I don't think I can liscensing another design.

Hey, that's less than I paid for my TC Electronic D-Two!

The good thing about a Delay as a part of a _modular_ synth is that you can
add a lot of features just as you need it, with other modules. Don't worry
about the "right" Loop filter for these echoes growing "distant" (loosing
bass and treble) - you can patch this up with any regular VCF in the system.
Well, you might provide a simple 6dB rolloff with variable corner frequency
for the simple stuff. Other than that, just make the feedback loop "open"
such that you can patch in whatever you need. Ever tried a frequency shifter
in the feedback loop? Or a simple ring modulator? Hmmm ...
What you *do* need is a _limiter_. Really. Especially with a lot of
external stuff patched in, which will push the loop gain above unity
easily, you want a limiter. Digital, part of the DSP code.
And provide a lot of Delay time. 20 seconds minimum. RAM is cheap
nowadays, and all the Loop Artists will run and buy a MOTM delay
if they can use it as a Looper. Provide switches for clean doubling
and halfing (is that the word?) of delay time, in addition to CV inputs.
Loopers like this. And a CV input for adding Tape-echo-like wow and flutter.
Make it stereo, if it's possible.

JH.

Re: [motm] Re: Delay any Delay buying :)

2003-10-31 by jhaible

> V/8ve input! Perfect for waveguide type stuff...

Right, almost forgot that!

BUT! If you want to use it for physical modelling, the V/8ve
input must be compensated for the fixed delay of the ADC / DAC
process! Implement it such that it goes down to 1ms or less,
and that the whole chain (ADC, RAM-cycles, DAC) tracks
to 1VOct, _not_ just the RAM part!

JH.

Re: [motm] Delay any Delay buying :)

2003-10-31 by Mike Estee

> The good thing about a Delay as a part of a _modular_ synth is that
> you can
> add a lot of features just as you need it, with other modules. Don't
> worry
> about the "right" Loop filter for these echoes growing "distant"
> (loosing
> bass and treble) - you can patch this up with any regular VCF in the
> system.

Amen! This is exactly what I'm talking about.

> What you *do* need is a _limiter_. Really. Especially with a lot of
> external stuff patched in, which will push the loop gain above unity
> easily, you want a limiter. Digital, part of the DSP code.

Unless the feedback path is all software, wouldn't the limiter need to
be before the AD? :( Saturated ADs sound horrible :(

> And provide a lot of Delay time. 20 seconds minimum. RAM is cheap
> nowadays, and all the Loop Artists will run and buy a MOTM delay

You know, you could probably get away with supporting regular DIMMs and
adding a bit of glue to make delay time dependent on how much Joe MOTM
User is willing to pony up for RAM. This pushes the cost of RAM down
through volume ;) Heck, can you even *buy* a 16MB simm anymore? In my
music I personally have never found a use for a delay longer than about
4 seconds, but for looping 20 seconds is probably scraping by. Be the
first on your block to have 1GB delay/looper ^_^

> if they can use it as a Looper. Provide switches for clean doubling
> and halfing (is that the word?) of delay time, in addition to CV
> inputs.
> Loopers like this. And a CV input for adding Tape-echo-like wow and
> flutter.

It seems to me like a delay and looper probably belong in different
modules. There are a certain class of features you want for looping
that aren't all that interesting for a delay line, and vise versa. I
have to admit, my lack of imagination is drawing blanks as to how a
looper would be really useful within the signal path of a patch. It
seems like more of a post processing toy. I can certainly imagine using
an electrix repeater with a motm during a performance, but I have a
hard time imagining how it would make sense within a patch.

Anyone care to enlighten me?

Show quoted textHide quoted text

> Make it stereo, if it's possible.

I really like Paul's multi-use format modules. It's a VCA, but a two
channel VCA with slightly different behavior for slightly different
problems. Or the filters with their double duty as clean sine wave
generators with 1V/Oct control. Or the White/Pink/Slow/Vibrato/S&H
module. I get good milage out of that one ;)

--mikes

Re: [motm] Delay any Delay buying :)

2003-10-31 by Paul Schreiber

OK, I'll try this *again*.

The basic feature set (algorithms, delay times, delay length) I *cannot change*. If it loops,
then it *loops*. If the filters are in SW, *so be it*. There are some things I can add around the
"core" DSP/codec section, but there's not much I can do (right now) about the DSP code.

Paul S.

Re: Delay any Delay buying :)

2003-11-01 by Mike Marsh

Maybe it would help if you tell us what is in the DSP code so we
could talk around that? I've heard some really good suggestions
(two inputs, two outputs for full control of feedback, etc.) It
would be nice to know what's etched in stone and what isn't.

Or did I miss that post?

Mike

Happy Halloween!

Show quoted textHide quoted text

--- In motm@yahoogroups.com, "Paul Schreiber" <synth1@a...> wrote:
> OK, I'll try this *again*.
>
> The basic feature set (algorithms, delay times, delay length) I
*cannot change*. If it loops,
> then it *loops*. If the filters are in SW, *so be it*. There are
some things I can add around the
> "core" DSP/codec section, but there's not much I can do (right
now) about the DSP code.
>
> Paul S.

Re: Delay any Delay buying :)

2003-11-02 by Roger Rossen

Lotsa good ideas rolling around on this.

I just wanted to ask - and maybe I missed a post on this or whatever -

Are we talking a 'stereo' delay? I ask this because, as I babbled
on before about how delays and 'time shifting', etc - REALLY open up
a lot of new sound possibilities...these possibilities are seriously
diminished however - with a mono concept.

I realize this may offend any hard core 'analog' disciples - and you
can always just buy 2 (which is good for the revenue stream, but less
likely to happen on the part of the buyer) yet I thing this issue
should be dealt with from a 'biggest bang for the buck' sort of basis.

Or most importantly - the biggest 'aural capabilties' for the buck

Somehow or other my MOTM is going to be stereo- "end of
discussion...for me anyhow" - and I know we all know of various ways
to accomplish this - but delays, are REALLY a whole new world, in the
stereo domain. And they get pretty boring -in mono, especially when
you got a Lexicon (a few really good ones for really, really cheap
comparatively speaking to yester-year)

Plus being somewhat of an anal 'supreme audio quality idiot' and
having performed one too many times through Fender Twin Reverbs,etc
(with 20 grand in keyboards or such) - I have long since determined
that even my on-stage monitors be stereo. Its just too damn
depressing to have your $10K Kurzweil, Triton, etc.. coming out mono -
It drive me to pyschopathic proportions...and makes me want to kill
all guitarist and anybody else who can sound great via a mono signal
path!

I'll leave any discussiom on dolby 5.1 for a later date----lol

My 2 cents -
(Thats all I have left - after buying way too many toys.!!!)

Rog

Re: Delay any Delay buying :)

2003-11-03 by Scott Gibbons

>The basic feature set (algorithms, delay times, delay length) I *cannot

change*. If it loops,

>then it *loops*. If the filters are in SW, *so be it*. There are some things I

can add around the

>"core" DSP/codec section, but there's not much I can do (right now) about the

DSP code.

What sort of features are possible for us to request? I'm VERY excited about
this module, but I'm not sure what kind of features are possible for you to
work around in the core DSP. My ignorance, sorry. Can you go into it a
little more? I have a feeling for what's NOT possible in this situation, but
what IS possible for us to chime in about?

FWIW:
Robert's suggestion of having an insert available for filters is stellar. I
would prefer an insert over having a built-in LPF, because I use LPF just as
often as BP or HP with regen'd delay. Also, I'd love to be able to insert
chorus in there, some gain modulations (so delays become grainy over time!),
a digital resampler (lower the bit depth with each delay!), or some
reverb... Man, that would just open up so many possibilities. Is it
possible?

best,
- Scott
____________
http://www.red-noise.com
http://www.strawberryplanet.org

Re: [motm] Delay any Delay buying :)

2003-11-03 by Scott Gibbons

> on before about how delays and 'time shifting', etc - REALLY open up
> a lot of new sound possibilities...these possibilities are seriously
> diminished however - with a mono concept.

Not necessarily... Different techniques call for different tools. It depends
on how you mix and what your arrangement is like. If you're just working on
a single sound, sure, one mono delay is going to be flat. But if you have a
busy mix, a stereo delay could easily make the track feel cluttered and
murky.

best,
- Scott
____________
http://www.red-noise.com
http://www.strawberryplanet.org