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Playing filter resonance (Sub 37)

Posted: Sat Mar 03, 2018 7:04 am
by Dapifer
Has anyone had any luck using the filter resonance to create a sine wave and actually getting it to track properly? I tried this a while back and decided to revisit it after Moog posted a video on it the other day but I can't seem to get it to track in tune even across one scale (I'm using the KB track dial at 1:1 as the video suggests).

Anyone know what I'm missing here?

Re: Playing filter resonance (Sub 37)

Posted: Mon Mar 05, 2018 4:18 pm
by DrJustice
Two things may cause that: The pot positions/markings aren't precise and the filter tuning may be a little stretched or compressed.

On my Sub 37, I find that a tracking value of 8127, as indicated by the editor, gives me good filter tuning over at least three octaves. If I set the tracking knob visually to 1:1, the editor reports a value of 8256. The ideal 1:1 tracking value, as in the numerically correct half of the knobs range, should be 8192. So as you can see things aren't perfectly aligned. This will vary slightly with temperature and between different examples of the Sub 37. The patches I've made with resonating filter tracks fine (the room I have the S37 in is always at roughly the same temperature, so I guess that helps).

Re: Playing filter resonance (Sub 37)

Posted: Tue Mar 06, 2018 5:38 pm
by wave100
Hi - I have the Sub Phatty... on it I have to make sure that the filter envelope knobs are turned down as well as the filter envelope amount set to the middle, there has to be no modulation going to the filter. It works reasonably well in that situation.

Re: Playing filter resonance (Sub 37)

Posted: Tue Mar 13, 2018 7:17 am
by Dapifer
DrJustice wrote:Two things may cause that: The pot positions/markings aren't precise and the filter tuning may be a little stretched or compressed.

On my Sub 37, I find that a tracking value of 8127, as indicated by the editor, gives me good filter tuning over at least three octaves. If I set the tracking knob visually to 1:1, the editor reports a value of 8256. The ideal 1:1 tracking value, as in the numerically correct half of the knobs range, should be 8192. So as you can see things aren't perfectly aligned. This will vary slightly with temperature and between different examples of the Sub 37. The patches I've made with resonating filter tracks fine (the room I have the S37 in is always at roughly the same temperature, so I guess that helps).
Thanks, how did you find the sweet spot though? was it just trial and error, I find the variables between setting the filter freq and the key tracking make this very difficult.

Also how do you get the editor to display the values like that? When I adjust the key tack dial in the editor I just see percentage displayed.

Re: Playing filter resonance (Sub 37)

Posted: Tue Mar 13, 2018 11:18 am
by DrJustice
Yes, it was by trial end error. I used another synth as the pitch reference, then tuning the resonating S37 filter to a C (that can be a bit fiddly sometimes, you may have to adjust it from either below or above the C to hit it precisely since the filter may want to "stick" a little in some places), then testing if the tracking was stretched or compressed by playing an interval of three octaves on both synths, adjusting the tracking a bit (to the left if it was stretched and to the right if it was compressed), retuning the filter, rinse and repeat. It may take a few minutes to find the exact tracking value.

Do this when the synth is properly warmed up, say after 30 minutes. The value you end up with ought to be good for reuse on your specific example of the Sub 37.

The key tracking knobs in the bottom LFO section display a percentage, but the one in the filter section, which is the one to use, displays a number 0 and 16383.

Re: Playing filter resonance (Sub 37)

Posted: Sat Mar 17, 2018 6:41 pm
by Dapifer
You were right! Thanks. That sweet spot on the editor seems to work for me too.