KVR Audio

Scrubbing Monkeys · Post by **Scrubbing Monkeys** » Wed Jul 19, 2017 10:19 am

Cool!,

After playing Galaxian for a few minutes, trying to destroy the evil spectrum. I gave up realizing my artillery was never going to hit the evil spectrum.

now on to making sounds.

I see we now have a master velocity control. Thanks. Is velocity also an option to modulate parameters?

I may have given some bad info concerning how to use arftertouch as well. I was sure that it was a modulation option but I dont see it.

Any plans to modulate the filter faders on the main panel?

Thanks for all of your work on this.

RPH · Post by **RPH** » Wed Jul 19, 2017 3:28 pm

Cheers on the release!

I think panel mode name "filter" is a bit confusing, shouldn't it be named "EQ"?
Furthermore, can't really see a use for that overlay now as it lacks guidelines ( y-axis = dB, x-axis = freq in Hz ).
Same for panel mode "overlay", it lacks guidelines. When I play notes I only see the notelines, but which note it is I can't see ( I often play notes on my computer keyboard in Renoise ).

FathomSynth · Post by **FathomSynth** » Wed Jul 19, 2017 3:47 pm

SM, Thanks for your post. I just got done laughing for five minutes and am still recovering.

RPH, Thanks also for responding. Here's more details on both your ideas.

Yes, I will think of a better name for the filter option.
I agree, the overlay spectrum should have the frequencies labelled in some way.
Same goes for the notes, I will add the note numbers as small labels "C3" ect.
A lot of ppl have requested velocity as a modulator so I will try to get that in this next releases.

Yes, I plan on making the faders both modulate-able and host automate-able, and in addition
also able to function as mod sources like the 2D pads. I will try to get that in soon.

Ok, I need to go work on the Asteroids overlay now ...

overhishead · Post by **overhishead** » Wed Jul 19, 2017 8:35 pm

what sort of objects in Fathom require pre-calculation?

FathomSynth · Post by **FathomSynth** » Wed Jul 19, 2017 9:23 pm

Oscillators, Modulators and Modulations.

All the alias free oscillator waveforms are created from either an array of sin waves
or a Fast Fourier Transform of the raw edited waveform. In either case we must pre-calculate
the waveform cycle so at run time the oscillator fetches each sample from a buffer
rather than performing any kind of computation. This reduces CPU and maximizes polyphony.

Same for Modulator buffers. We want to avoid any computation of exponential curves
to create an envelope at run time so we pre-calculate the modulator buffer and,
like the oscilaltors, each sample from the modulator is a single table fetch (fast).

Parameters which do not affect a buffer such as Pitch Note or Pitch Fine will not have any
calculation delay. Parameters which do affect a buffer such as oscillator Partials or Envelope Period
will have a calculation delay. The dial delay is the price paid for super fast run time cpu.

In the future I will figure out a clever way of making the dial delay invisible to the ears
such as double buffering during the calculation so there is no blank spot.

RPH · Post by **RPH** » Thu Jul 20, 2017 10:24 am

Tiny bug:

SV Filter graphics between about 16kHz and 19kHz has a strange bump.

fathom-SVfilter.jpg

FathomSynth · Post by **FathomSynth** » Thu Jul 20, 2017 4:41 pm

That looks correct. The bump of course is the resonance.

But you are observant noticing the different frequency response of this filter compared to the others.

Standard second order digital filters normally use the Bi-Quad topology which consists of
two feed forward and two feed back circuits. The low pass version of the Bi-Quad
is pinned to zero amplitude at the Nyquist frequency which at 44100 is 22050 Hertz.

The SV or State Variable filter uses a completely different topology based on the
analog version of the filter. One of the reasons it is used is that the frequency response
is different than the Bi-Quad and at high frequencies of the resonant peak it is not
pinned down to zero at the Nyquist.

You can see this by adding both filters to the main view and gradually moving the
cutoff frequency up on both filters. You will notice that the State Variable filter
tends to keep its shape up into the high frequencies without getting "squashed"
as it reaches the Nyquist, as does the LPR Bi-Quad.

In practice you would want to use the SV LPR instead of the standard Bi-Quad LPR
when you want to bump the frequency response with a resonant peak in the high
frequencies but keep a minimal amount of very high frequency content from the original signal.

I really should change the frequency domain limits for this filter so you can see the whole
frequency response in the high end.

RPH · Post by **RPH** » Thu Jul 20, 2017 5:55 pm

Thanks for your explanation. Yea the bump is the reso, but it's only that high at the given freq range with the Q setting you see.
It acts that way up until almost Q = 8.
At Q > 8 the bump graphics displays correctly ( it seems when it hits the ceiling it's not going up that abrubtly ).

I made a video to show you what I mean, to be sure we're looking at it the same way: https://youtu.be/UMeOUzjgm0o

FathomSynth · Post by **FathomSynth** » Thu Jul 20, 2017 8:47 pm

Oh, That's a bug!

The gain should not be jumping like that.

I'll take a close look at that filter algorithm for this release and fix that.

Vertion · Post by **Vertion** » Fri Jul 21, 2017 1:33 am

FathomSynth,

Just bought your synth via KVR Marketplace without first trying the demo for 11 dollars. Fathom installation was clean and simple, and it works wonderfully. Good synth. Good idea. Good work.

V

FathomSynth · Post by **FathomSynth** » Fri Jul 21, 2017 4:13 am

Thanks! That's good to hear.

RPH · Post by **RPH** » Tue Jul 25, 2017 12:18 pm

I notice with the new overlay with notes that some of the notes played are not always displayed.
A pattern with melody that I made in Flstudio 12.4.2 is looped, while checking the overlay one time all notes are displayed and the next time around a couple are not.

The range is btw not all possible notes, it starts at C2 in Flstudio and ends at C7. So e.g. B1 note isn't shown.

koalaboy · Post by **koalaboy** » Tue Jul 25, 2017 3:13 pm

Is there any plan for the interface to be scalable ? It's tiny on a 4k display.

FathomSynth · Post by **FathomSynth** » Tue Jul 25, 2017 4:03 pm

RPH, OK, I will look into the note missing problem.
I tested it a lot and never saw it miss any, so could you save the preset and send me the xml file,
and also export the midi sequence and send it to me, also which host?
The note message is automatically disabled if CPU goes over a high threshold
so it could happen if you are on the edge with CPU usage.

Koalaboy, Yes, in the near future the UI will be resizable since I built that into the interface,
I just had not turned it on yet since it will require a lot of testing to make sure nothing is missed.
But could you send me or post a screen shot of the display with the GUI showing small, please.

FathomSynth · Post by **FathomSynth** » Tue Jul 25, 2017 4:19 pm

Also, friends, I need your help with something.

One of my user's reported a really bad audio clicking problem with the mono version,
and I will include the audio file here.

Sales dropped to almost zero after release 109 even though it had some really cool features,
and I'm strongly suspicious that I broke something really bad and did not find it in testing,
possibly with the mono version.

I test for audio quality extensively, but if a bug got through in the mono version and
new users hear clicking when they first try it, its understandable that most people would
simply never buy the synth, without necessarily reporting the problem.

Has anyone experienced any audio clicking especially with the mono version,
if so send me details such as which host, and even email me the preset xml so I can debug this.

Attached: Clicking audio mp3 (zipped).

Fathom Synth Development Thread