Page 1 of 1

Possible New AutoTune Method for the Phattys?

Posted: Thu Jun 23, 2011 5:26 pm
by Briman
Hey Amos...

Howdy. I am wondering if there is another way to implement AutoTune (AT) on all the Phattys?

Right now... with AT On... and when a Phatty is Powered ON... AT attempts to tune to whatever the last Midi Note it was sent.

However... AT seems to wait for the Phatty's Oscillators to warm up to their "normal operating temperature"... before AT can "Hold" it's tuning!

When I Power Up my SP... and play a "C" note using OSC 1... my Tuner says it's a G# note... "below" the "C"... so it starts down 4 semitones.

Then as it warms up... the pitch gradually rises UP to a "C"... but takes about 60 minutes on my SP to reach... then Hold... proper pitch!

Why not on Power UP... have AT "sense" that OSC 1 is Way Flat... and have it raise the G# note up to the "C" note right away?!
This would be similar to... if a Phatty was in "Fine Tune ON" mode... and a User tuned it up to pitch manually... with the Fine Tune knob.

So in effect... AT would raise OSC 1's pitch up to the "C" note IMMEDIATELY... meaning there would be "NO Warm Up To Pitch Time" to wait for!!! :)

Then... as the Phatty warms up... AT would effectively keep "lowering" OSC 1's pitch... while keeping it's "C" Pitch constant...
until OSC 1 warms UP to the "Actual C Pitch"! Then... when the Phatty is at "normal operating temperature"... AT would simply Hold it there... in tune!

Ideally... if this could be done... it should also apply to OSC 2 as well... so there's no waiting for any 2 Oscillator Patches'
"Detuned Amount" to stabilize... as AT would already be tuning both Oscillators Up to Pitch... so as to "Hold" a Phatty's Tuning constant...
"Right from Power ON!" :)

Hopefully... this makes sense to you... and could possibly be implemented in the Phatty's OS... sometime in the near future?! :)
Many thanks!

Brian :)

Re: Possible New AutoTune Method for the Phattys?

Posted: Thu Jun 23, 2011 6:04 pm
by ark
Are you really saying that when you first turn your Phatty on, the oscillators are 4 semitones flat? I find it hard to believe that that's normal behavior.

Re: Possible New AutoTune Method for the Phattys?

Posted: Thu Jun 23, 2011 8:21 pm
by Amos
4 semitones flat isn't at all unusual. The Voyager has the same oscillator design and is just as flat on power-on. Warm-up time can differ depending on a lot of factors, but the pitch-CV circuit temperature dependence causes about that much swing in pitch from room-temperature to full operating temp.

Re: Possible New AutoTune Method for the Phattys?

Posted: Fri Jun 24, 2011 4:03 pm
by Briman
Hey Amos...

Howdy. OK... only "ark" got an answer here?

Does this mean there is no real merit to my above... AutoTune revamp proposal then?
Many thanks.


Re: Possible New AutoTune Method for the Phattys?

Posted: Fri Jun 24, 2011 7:10 pm
by Amos
Sorry Brian :)

It should more or less already do the first part of your proposal... i.e. as soon as autotune kicks in it should start adjusting the fine tune voltage until concert pitch is reached. It's a moving target as the unit warms up and it stops doing it any time you play a key so it may seem to take a lot longer at first.

One thing you can try is turning the unit on and playing a note or two then going to the FINE TUNE page, set to AUTO and use CURSOR to move the cursor under the fine-tune note number. This forces the unit into auto tuning, and if you don't play any keys it will then proceed to do its thing until it thinks Middle C is in tune (60.00). This will take longer if the unit is cold and warming up but it should get there relatively soon. Then press PRESET to get out of that mode and try playing, see if the unit is anything like in tune.

Unfortunately, there's no way to auto-retune oscillator 2 while it warms up... Auto fine tune adjusts the fine tune voltage which is sent to both oscillators. It's a fact of physics, though, that the amount of detuning in each oscillator depends on the physical characteristics of the transistors involved. This means that each oscillator will have its own behavior as it warms up and though they'll all be very similar, they don't detune identically with temperature. So if you carefully detune the two oscillators a certain amount while they are fully warmed up, they will have to be fully warmed up again before the same tuning relationship will be restored. It's part of the living nature of analog circuits; we just have to live with it if we want to enjoy all the good things that come with the total package. :)



Re: Possible New AutoTune Method for the Phattys?

Posted: Sat Jun 25, 2011 7:55 pm
by Briman
Hey Amos...

Thanks for your reply. I've just been leaving my SP in AutoTune (AT) mode... so when I power it up... AT is already ON!
Then I immediately play it a "C" note to tune to. AT's first reading says 57.41 and then takes only about 5 minutes for it to read 60.00.

However... even when AT first reads 60.00... my SP is still 4 cents Flat on my Tuner... which is Way Too Flat to start playin Bass parts with!
It then takes another 55 minutes... for OSC 1's "actual tuning" to come up 4 cents to a "C" Concert Pitch... before my SP is usable to play Live!
(no opportunity for me to deal with tuning it Manually... in a Live situation!)

I just tried the method you suggested... with AutoTune OFF when I power up my room temp SP... then played it a "C" note FIRST, and THEN... I turned AT ON.
However... my SP didn't reach Concert Pitch any faster that way though... so I'll just leave AT always ON then.

Interestingly though... as mentioned in my post on... "SP Oscillator 2 taking forever to warm up"...
after installing your final OS 3.1... my SP's OSC 2 now only takes 30 minutes to reach Concert Pitch after power up...
and this is without any AT applied to it apparently!?

Anyways... so presently... I need to wait 1 Hour in Total before being able to use my SP to play Bass parts in tune... at Concert Pitch...
but I was hoping that a "Computer Controlled" Analog Synth could do better than that!?

Yes... I do understand all about Analog Circuits and warm up times etc... as I used to have an actual Minimoog D... and a Moog Source...
but unfortunately... they are both long gone.

It is great to have an actual Moog Synth again though... in the Slim Phatty... but with its present promo...
I didn't expect that it would have such a long warm up to Concert Pitch time. Nothing like a Real Moog though... once it gets goin! :)

btw: Here's the "MIDI BASS" Controller I will soon be using... as I have the 5-String Version on order: ... luxe-4.php

Meanwhile... I use the previous Midbase/Cyberbass model. This "Fret-Wired" technology works Great... as is Fast, and Accurate...
with no noticeable latency... unlike Pitch-to-MIDI systems! Video proof of this here:
There's nothing like playing a REAL MOOG... while not actually being a Keyboard Player! :)

Many thanks Amos & Moog!

Bye for now...
Brian :)