greetings

i find it difficult to build synth sounds using the pd oscillators and amp them to sufficient levels without hearing distortion when playing 3+ note chords. this is especially the case with lower notes in proximity to each other

if i turn overall gain down, obviously it goes away. however this is a relatively low volume when compared to external sound through pd or even playing samples. i've used lop~, hip~, tanh~, clip~ and limiter~ to no avail

Hi Kenny,

I get the same results, up to [*~ 10] with single voice but lower as voices are added. But still, even with several voices, the volume is pretty decent on my side. I suspect this is due to the algorithm itself indeed.

And thanks for the patches, they are indeed very nice (I particularly likes [leslie~], such a handy way to add tremolo and overdrive to a signal!).

Take care,
Gilberto

Hi all, no distortion here. I played the 45-49-52 chord and it only produced audible distortion at [.~ 7], so [.~ 6] was the healthy value here.

I've added an array for visualization, just before the [dac~]. It graphs 1 second, (if your current sample rate configuration is 44100), about once per second.

Visualizing 1 second.zip

There you should see that the waveform is always far from distortion. It's only when you push it beyond [.~ 6] that you might start getting some distortion.

So the patch is working well. Do you see the same low level waveform as I see? Or do you see the waveform getting out of the visualizer/rectangle?

@LandonPD Hi Landon,

I think that those values for the multiplication are quite unorthodox (imagine multiplying an [osc~] by [*~ 7] and getting a decent waveform?!), but the problem is that Kenny finds the volume from the synth to be too low even when its sound is about to crack, and low volume means when compared to a sample being played by [readsf~], for instance.

I made some tests with your patch and it seems to me that the sound cracks before it reaches the limits of the visualizer's rectangle. For a 3 note chord, it cracks at around [*~ 5.5] for me. Now if you connect an [env~] and a number box to it, you will see that the more notes you have, the lower will be the amplitude given by [env~] in which distortions occur. I don't find the volume particularly low when it is about to crack, but I am starting to agree that it should show distortions for a little higher volumes.

Take care,
Gilberto

Hi all,

What about using a limiter in the following way? It seems to be working quite well now: synth-with-limiter.zip

Take care,
Gilberto

Hello again - Sorry for the delay.

LandonPd, I tried the patch with the array and the sound breaks up far below the the -1 to 1 limits. If I record the loudest 'clean' signal out to a program like audacity, it's definitely reflected as a weak signal. If I amplify the audio in audacity to fit the -1 to 1 limits the same crackling distortion emerges.

Gilberto, I wasn't able to fix the issue with the limiter. It does the job initially, but if I compensate afterwards to get a sufficient gain level, the distortion comes right back.

I think you might be right about the 'algorithm', but I'm confused about this since the patch seems to be basic additive synthesis with osc~s.

Here is one more patch with a simple two-note chord. I get distortion at *~6 with a weak signal in the array window.

The high *~ values I believe are just balancing out the low *~ values at the output in each voice-abstraction.

At some point I'll try sampled sine waves and see if that helps

.w:limiter.zip

OK, this is going to be a quick and short post due to time constraints, sorry! Maybe I can answer more properly later, and download the test files..

@gsagostinho Yes, I understand, I agree that the algo may have some issues. The thing that is making things complicated, as regards the original Hammond patch, is that when we play something it's always a little different. So, even though we play the same chord or note, the experiences differ because of the particular peaks and valleys combinations. This means that if I play the 45-49-52 chord three times I'm going to get three different results. Maybe the 1st played chord was clean, the 2nd played chord was distorted, and the 3rd played chord was clean again.

@kenny_t The patch may have some issues, but this seems to be mainly a problem in your system. I suggest that you generate a (full blast) sine tone in Audacity and see if you get distortion. Maybe you should choose the same output configuration as you have for Pd, thus the test will be more valid.

Hi @LandonPD, hi @kenny_t,

Look, I am also having distortions when the wavelengths are within the graph's rectangle (that is, when they still in between -1 and 1). That said, the patch w:limiter.zip does not produce any distortions on my system at all. So apparently it could be both things: the abstraction may have some strange problem and you may have a problem with your system as Landon writes.

Take care,
Gilberto

Hi Gilberto, your limiter improved the patch. I still get some little distortions but things improved a lot. It's clear to me now that @kenny_t has some distortion issue in his system...damaged audio driver, inappropiate sound settings?

"I'm confused about this since the patch seems to be basic additive synthesis with osc~s.".

Well, there's some [noise~] in there, and limiters, and envelopes...too many things going on. It's additive sinusoidal synthesis but there are various factors or parameters that alter sinusoids over time.

By the way, the array that I added (for visualization) uses Bezier curve. If I had used points instead, it would have been easier to see out-of-range samples with the naked eye. Choosing points is a good strategy when trying to see out of range values. In fact, they are not really points...the data is shown as horizontal lines.

@gsagostinho
@landonPD

turns out it was corrupted audio from the headphone jack. i'm so happy it wasn't the software! and i've never been so relieved to have something wrong with my computer! lol

i found this out when testing on another mac & testing on a firewire mixer - so i'll be buying one of those for now

thanks for the help - attached is another test patch that is unnecessary i guess, but may have some useful tools for the organ

h-organ.zip

edit - noted

Hi Kenny,

I am glad to hear that Also, thanks for the patch, I am particularly happy to find the drawbars abstraction, it is really handy!

Take care,
Gilberto

PS: when replying to someone, you can use the @ symbol, such as @LandonPD, so the person gets a notification of a reply (note that this is not necessary for the person who started the post, he will always receive notifications)

Great, Kenny. I'm also glad you've solved the problem.

And don't throw away that headphone jack...it might be great for heavy rock listening!

Also thanks for the patch, I'll be looking at that tomorrow.

Have a nice day