Thanks or the feedback!! I have a good KS synthesizer patched up That gives me good results, with the block size for the waveguide set At blocksize one as you suggested.

The table is a good idea, instead of time dialating the excitation waveform or changing the delay time to get different pitches, I can just read / write the table (delay line) at different rates (in modeling terms, changing the speed of sound). Easier, and only requires a constant length table copy for each note.

I have been peaking into the source with the intent of creating an external which performs the same function as the current delay object (with vd~) but has an input to preload the delay line from a table.

Is there an example that you know of that uses tabread and write as a delay line??

Thanks!!

Michael

-----Original Message----- From: derek holzer [mailto:derek@x-i.net] Sent: Wednesday, November 29, 2006 8:01 PM To: Michael Garrett Cc: pd-list@iem.at Subject: Re: [PD] Pre Loading a Delay Line

Hi Michael,

Michael Garrett wrote:

I need to pre fill a delay line, in a Karplus Strong oscillator. That data will then be overwritten during the duration

Of the 'note'. Is there a 'built in mechanism for accomplishing this, or do I need to construct something using a table.

I need the delay line to be interpolating. I am setting the delay based on the incoming note, and ideally would fill the line with the same waveform, time dilated to fit the required length.

Short answer: no, there is no way to "pre fill" the delay that is native to the [delwrite~] object.

You're on the right track to use a table, however. You could also go a step further and build your own delay line using two tables, which transfer back and forth to each other with [tabwrite~], and could be preloaded with whatever you need. The [tabread4~] object should read your tables with enough interpolation for Karplus Strong synthesis. Otherwise, [delwrite~] and [vd~] are normally used for this, and [vd~ ] seems to interpolate well enough. You'll have to set a very low blocksize with the [block~] object to synthesize high frequencies in any case.

In the past, there's been quite a bit of discussion about KS synthesis on the list. And it sounds like you have a rather complicated approach to it (or at least more so than standard KS synthesis). If you're interested, it might be worth checking some of these threads for more tips.

best, d.

A little better explanation:

The idea is to read from the table, and feedback with and attenuated delay, back into the table, thereby modifying the table, the table at any given time, being the KS 'waveform' at that instant. So, reading attenuating and feeding Back the signal at varying rates, is equivalent to modifying the 'speed of sound' inside the 'waveguide'.

So something like this: Read out from the table at the current (or delayed) index, send that to the output, take that sample attenuate it, and write it back to the using the delay index, increment the indices (with modulo) thereby replacing the original table with the time modified data at each time (or sample index). The read .. modify.. feedback rate, is equivalent to the 'propagation' of waves in the 'waveguide' (or the KS 'delay' unit).

So of you were watching the table in real time, you would see the internal guts of the KS algorithm, modifying the wave (table)in real time.

Once the energy in the table has decayed to zero, silence would be output...

Another note would be triggered, by copying the table back into the 'waveguide' (or table or delay line depending on the implementation).

mcg

-----Original Message----- From: derek holzer [mailto:derek@x-i.net] Sent: Thursday, December 07, 2006 10:16 AM To: Michael Garrett Cc: pd-list@iem.at Subject: Re: [PD] Pre Loading a Delay Line

Hi Michael,

technically, reading from a table and changing the playback speed isn't really KS. That's more like wavetable synthesis with en envelope. I always thought KS was dependent on attenuated feedback. But if it works do it!

I don't have a handy example of tabread/tabwrite as a delay, unfortunately. Frank Barknecht has a [pluck~] abstraction in CVS:

"/abstractions/footils/foo/pluck~.pd"

But I'm sure it uses [vd~]. Might be interesting to have a look at. And this abstraction from Orm Finnendahl adapted by João Miguel Pais:

http://lists.puredata.info/pipermail/pd-list/attachments/20060412/75593d59/k s.obj

(textfile...save as "ks.pd")

Another idea, why not preload the delay line in realtime by triggering a sample when you need the note? That seems much more like "textbook" KS, which is usually triggered by a burst of noise (though I prefer a mic input).

best, d.

Michael Garrett wrote:

Thanks or the feedback!! I have a good KS synthesizer patched up That gives me good results, with the block size for the waveguide set At blocksize one as you suggested.

The table is a good idea, instead of time dialating the excitation

waveform

or changing the delay time to get different pitches, I can just read /

write

the table (delay line) at different rates (in modeling terms, changing the speed of sound). Easier, and only requires a constant length table copy

for

each note.

I have been peaking into the source with the intent of creating an

external

which performs the same function as the current delay object (with vd~)

but

has an input to preload the delay line from a table.

Is there an example that you know of that uses tabread and write as a

delay

line??

Thanks!!

Michael

-----Original Message----- From: derek holzer [mailto:derek@x-i.net] Sent: Wednesday, November 29, 2006 8:01 PM To: Michael Garrett Cc: pd-list@iem.at Subject: Re: [PD] Pre Loading a Delay Line

Hi Michael,

Michael Garrett wrote:

...

I need to pre fill a delay line, in a Karplus Strong oscillator. That data will then be overwritten during the duration

Of the 'note'. Is there a 'built in mechanism for accomplishing this, or do I need to construct something using a table.

I need the delay line to be interpolating. I am setting the delay based on the incoming note, and ideally would fill the line with the same waveform, time dilated to fit the required length.

Short answer: no, there is no way to "pre fill" the delay that is native to the [delwrite~] object.

You're on the right track to use a table, however. You could also go a step further and build your own delay line using two tables, which transfer back and forth to each other with [tabwrite~], and could be preloaded with whatever you need. The [tabread4~] object should read your tables with enough interpolation for Karplus Strong synthesis. Otherwise, [delwrite~] and [vd~] are normally used for this, and [vd~ ] seems to interpolate well enough. You'll have to set a very low blocksize with the [block~] object to synthesize high frequencies in any case.

In the past, there's been quite a bit of discussion about KS synthesis on the list. And it sounds like you have a rather complicated approach to it (or at least more so than standard KS synthesis). If you're interested, it might be worth checking some of these threads for more

tips.

best, d.

Attached is the base KS synth that I am using. It sounds like a PVC pipe Being hit which was my goal. The delay is excited with a cosine enveloped bandlimited noise pulse. If you add some spikes to the table, you can change the excitation sound.

Preloading the table, gets more low frequency energy into the table faster, allowing better generation of low frequency sounds. (I am a bass player!!)

mcg

-----Original Message----- From: derek holzer [mailto:derek@x-i.net] Sent: Thursday, December 07, 2006 12:26 PM To: Michael Garrett Cc: pd-list@iem.at Subject: Re: [PD] Pre Loading a Delay Line

I was wondering how you arrived at this idea of "preloading" the delay line. From reading this I would say definitely trigger your waveforms as samples into a delay line with feedback. The waveform should be the same length as your delay line. By setting your feedback and playback readpoints to the same, you can change the functional length of delay without changing it's actual (or theoretical maximum) length. So you'll need to be able to call up the length of the waveform (unless they are all the same in your implementation) in miliseconds and send that to the [vd~] used for playback and for feedback as a starting point, from which you would adjust to change pitch. The first thing you would hear then is the sampled waveform, and then after that iterations of that waveform decreasing in volume. Classic KS.

Or am I missing something? It seems you're taking a more complex approach to this than basic KS, and I wonder what the aim is in terms of sound...

best, d.

Michael Garrett wrote:

A little better explanation:

The idea is to read from the table, and feedback with and attenuated

delay,

back into the table, thereby modifying the table, the table at any given time, being the KS 'waveform' at that instant. So, reading attenuating and feeding Back the signal at varying rates, is equivalent to modifying the 'speed of sound' inside the 'waveguide'.

So something like this: Read out from the table at the current (or

delayed)

index, send that to the output, take that sample attenuate it, and write

it

back to the using the delay index, increment the indices (with modulo) thereby replacing the original table with the time modified data at each time (or sample index). The read .. modify.. feedback rate, is equivalent

to

the 'propagation' of waves in the 'waveguide' (or the KS 'delay' unit).

So of you were watching the table in real time, you would see the internal guts of the KS algorithm, modifying the wave (table)in real time.

Once the energy in the table has decayed to zero, silence would be

output...

Another note would be triggered, by copying the table back into the 'waveguide' (or table or delay line depending on the implementation).

mcg

-----Original Message----- From: derek holzer [mailto:derek@x-i.net] Sent: Thursday, December 07, 2006 10:16 AM To: Michael Garrett Cc: pd-list@iem.at Subject: Re: [PD] Pre Loading a Delay Line

Hi Michael,

technically, reading from a table and changing the playback speed isn't really KS. That's more like wavetable synthesis with en envelope. I always thought KS was dependent on attenuated feedback. But if it works do it!

I don't have a handy example of tabread/tabwrite as a delay, unfortunately. Frank Barknecht has a [pluck~] abstraction in CVS:

"/abstractions/footils/foo/pluck~.pd"

But I'm sure it uses [vd~]. Might be interesting to have a look at. And this abstraction from Orm Finnendahl adapted by João Miguel Pais:

http://lists.puredata.info/pipermail/pd-list/attachments/20060412/75593d59/k

s.obj

(textfile...save as "ks.pd")

Another idea, why not preload the delay line in realtime by triggering a sample when you need the note? That seems much more like "textbook" KS, which is usually triggered by a burst of noise (though I prefer a mic input).

best, d.

Michael Garrett wrote:

...

Thanks or the feedback!! I have a good KS synthesizer patched up That gives me good results, with the block size for the waveguide set At blocksize one as you suggested.

The table is a good idea, instead of time dialating the excitation

waveform

...

or changing the delay time to get different pitches, I can just read /

write

...

the table (delay line) at different rates (in modeling terms, changing

the

...

speed of sound). Easier, and only requires a constant length table copy

for

...

each note.

I have been peaking into the source with the intent of creating an

external

...

which performs the same function as the current delay object (with vd~)

but

...

has an input to preload the delay line from a table.

Is there an example that you know of that uses tabread and write as a

delay

...

line??

Thanks!!

Michael

-----Original Message----- From: derek holzer [mailto:derek@x-i.net] Sent: Wednesday, November 29, 2006 8:01 PM To: Michael Garrett Cc: pd-list@iem.at Subject: Re: [PD] Pre Loading a Delay Line

Hi Michael,

Michael Garrett wrote:

...

I need to pre fill a delay line, in a Karplus Strong oscillator. That data will then be overwritten during the duration

Of the 'note'. Is there a 'built in mechanism for accomplishing this, or

...

...

do I need to construct something using a table.

I need the delay line to be interpolating. I am setting the delay based on the incoming note, and ideally would fill the line with the same waveform, time dilated to fit the required length.

Short answer: no, there is no way to "pre fill" the delay that is native to the [delwrite~] object.

You're on the right track to use a table, however. You could also go a step further and build your own delay line using two tables, which transfer back and forth to each other with [tabwrite~], and could be preloaded with whatever you need. The [tabread4~] object should read your tables with enough interpolation for Karplus Strong synthesis. Otherwise, [delwrite~] and [vd~] are normally used for this, and [vd~ ] seems to interpolate well enough. You'll have to set a very low blocksize with the [block~] object to synthesize high frequencies in any case.

In the past, there's been quite a bit of discussion about KS synthesis on the list. And it sounds like you have a rather complicated approach to it (or at least more so than standard KS synthesis). If you're interested, it might be worth checking some of these threads for more

tips.

...

best, d.