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asb2m10 / dexed

DX7 FM multi plaform/multi format plugin
GNU General Public License v3.0
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LFO speed range twice too small #291

Open mtarenskeen opened 3 years ago

mtarenskeen commented 3 years ago

A quote from the original DX7 manual:

"The LFO output can be varied in "speed" over a range from under 1 Hz to about 50 Hz"

According to my own measurements it goes to just below 48 Hz. But now I measured Dexed output and it seems all LFO speed frequencies are a factor 2 too slow! The upper limit when LFS=99 that I measured using Dexed was 23.81 Hz. I have not checked the sourcecode (yet).

If Dexed wants to be as close as possible to a real DX7 I think this is a bug that should not be difficult to fix?

flubber2077 commented 2 years ago

Confirming the quote is in the manual, and that Dexed currently maxes out at 23.81 Hz for the LFO. However I don't have a DX7 to test against.

bryc commented 2 years ago

Not sure if this is related, but 0.9.6 has a noticeably different (faster) LFO period than 0.9.1.

I made sure both versions were set to "Modern" engine, opened the "LAURIE" patch, put Op4 level to 0, and played C4 on both:

(Also the reason I used "Modern" is that "Mark I" sounds different in 0.9.1 vs. 0.9.6 so they weren't comparable.)

https://user-images.githubusercontent.com/1408749/176983687-f339ca97-304c-4193-b46c-1d97a6202a0e.mp4

Edit: Ok this might be unrelated to the LFO and instead could be related to different 'Detune' behavior. Worth checking if it's a regression though.