DIMENSION - waveguide (Physical Modelling) via Impulse responses?

Is there a tutorial on this feature as it's an area of dimension with heaps of sonic scope that I would truly love to explore myself.

I never did get a tutorial written for waveguide/wavetable synthesis in Dimension. Once I got started, it went on & on & on ...

For now, load up any of the wavetables in a single Element from the 00 - Wavetables folder in Dimension, or the 20 - Waveguide .sfzs. If you want to roll your own .wavs in something like Sound Forge, I believe that the limit on a .wav file is 2048 samples. That or under turns an Element into an oscillator or a waveguide automatically.

Strangely enough (<g>), it's remarkably similar to how PSYN works [the wavetable synthesis; that is]. If you're going to try the SF route, make sure to turn off the Auto Preview and/or turn you monitors'/headphones' volume way down. Those short cycles will really push some air with your speakers up, and the pop could be harmful to your ears/speakers at high SPL.

I agree; this process needs to be fleshed out with a few tutorials; the potential is huge. I might tackle this myself, but it'd had to be 100% accurate, because you never know who might be reading them here at the forum ... <g>

ORIGINAL: b rock
I agree; this process needs to be fleshed out with a few tutorials; the potential is huge. I might tackle this myself, but it'd had to be 100% accurate, because you never know who might be reading them here at the forum ... <g>

<scuffling and slight cough heard from Techead lurking in the background>

Each element in Dimension can make sound in three different ways: sample-playback, wavetable oscillation or waveguide. Which might result confusing at first is that the three synthesis types require a sample to play. Here's how:

Sample Playback
-------------------
I guess the first one is very well known: just drop a wav/ogg/aif/aiff/sfz file into Dimension, and presto. Any samplerate, any bit-depth, any format (mono/stereo), with any amount of loops. It'll follow all the mappings in any sfz format file, with all the bells and whistles.


Wavetable Oscillator
------------------------
In any synthesizer like Pentagon I or z3ta+, you'll see a 'waveform selector', which selects the waveform for the oscillator. Common choices are Sine, Square and Sawtooth, with some others called Partials, etc. That waveform is a mathematical representation of a single cycle of the oscillator, which be repeated over and over to generate a tone.

One might think that this is equivalent to 'loop' a single wave file, but it's not. To make a transparent, pristine oscillator, a process called 'bandlimiting' needs to be performed. This is, removing some harmonics in the spectra that would generate a nasty distortion when transposed.

Dimension features all those common oscillator waveforms, and more: it allows you to convert *any* wave file in the oscillator representation. To indicate Dimension that we want to turn the element into a wavetable oscillator, there're two methods:

1- Inside the sfz file
If you create an sfz file with the following:
<region> sample=MyWaveform.wav oscillator=on

The 'MyWaveform.wav' sample will be bandlimited and converted on load, and the element will behave as oscillator. When using this method, the file can be any size. This method offers the advantage of allowing you to map different waveforms on the keyboard, layer them, etc.


2- Direct sample-loading with less than 3000 samples
If you load a single file with less than 3000 samples, Dimension will say 'ok, it's a waveform definition'. This is the method used in all the factory wavetables. You can find them in the '00 - Wavetables' folder. Note that this works only for direct-loading: if you load the same file inside a .sfz file, you need to specify the opcode in (1). Note that the size of the file doesn't matter, as a 32-bit file will be four times bigger than a 8-bit file, both with 3000 samples.

So, when your neighbor asks 'how many waveforms does Dimension feature?', you now know what to answer: 'oh, just all'.


Waveguide Synthesis
-------------------------
A waveguide is a bidirectional delay line, at some wave impedance. In easy terms, you can think of it as a complex resonator, where if you make some initial short or burst noise, the resonator will continue 'vibrating' for a while, with a natural decay. This synthesis method has been introduced in the early nineties as a fresh way to synthesize plucked attacks and plucked strings. A waveguide is the most common component used in Physical Modelling.

In this method, we give Dimension a sample to provide the initial noise burst, or 'impulse'. This impulse has nothing to do with room/hall impulse responses used in convolution processors, but using those as bursts result in interesting sounds. This is the sfz syntax to turn an element into a waveguide:

<region> sample=MySample.wav waveguide=on

Beware of the length of the impulse you use: it might end in DC, with no sound produced. This is a normal consequence on waveguide synthesis. If you're up to investigate, just take a look at the stock impulses in '20 - Waveguide'. If you're after a sample of how waveguides can sound, check the 'PM Clav' patch, a physical modelled Wonder-like clav sound.

Hope this brings some light.

-René

Which brings me to another question: I have been converting some of the WusikSND format files into sfz format, however, it doesn't appear to have any loop points...is there any way to make these samples loop on the Dimension GUI, or is it another case of opening up the sfz and editing manually?

Seriously, Rene. Thanks for putting this one out. Doesn't matter where the information comes from, it just needs to be out there.
As usual, I learned a lot myself. It's always nice to get the information from the source.

Welcome Tom. However, I honestly think you do a much better job than me when translating information into human-readable text. The geek part in me is hard to turn off, and often won't spend time writing a decent an example here and there assuming something's obvious... when it might not. Just combine that with tarzan-level english, and presto: unreadable stuff.

So when you find some time, please translate my english-wannabe hieroglyphs. I use to read how you re-explain something I wrote a while ago just to capture more vocablary


Cheers,
-René

Yep, the loop_mode thing did it....

Regarding the oscillator=on thing: I assume it is only worth doing this in sfz files that reference one wave file? I presume that in any sfz that is made of more than one wave file (with different vel response ranges) won't work properly if they are all set to oscillator=on?

Regarding the oscillator=on thing: I assume it is only worth doing this in sfz files that reference one wave file? I presume that in any sfz that is made of more than one wave file (with different vel response ranges) won't work properly if they are all set to oscillator=on?

The oscillator= opcode works in a per-region mode. Therefore, you can have many parts of the keyboard with a different waveform, i.e. a sawtooth from C2 to B2, a square from C3 to B3, etc, or layers, or keyboard switching or any other type of input control defined in the sfz format.


-René