The Prophet '08 Among Prophets

Sacred Synthesis

Re: The Prophet '08 Among Prophets
« Reply #260 on: September 25, 2016, 10:20:28 PM »
I find the difference to be just barely discernible.  Nice patch, though.

I've always had my doubts about the whole "slop" approach to emulating a vintage analog synthesizer.  I've had enough experience with those old instruments, and honestly, I don't find the slop parameter to successfully simulate them one bit.  First of all, the worst thing about those old synths was the tuning problems.  How comical it is that now people pay to have a parameter meant to imitate the worst of their shortcomings.  But even more, the distinctive issue was that the oscillator beating rate gradually changed as you ascended and descended the keyboard.  At the bottom it would be one rate, and at the top it would be another.  But the rate did not change when you held a single note, unless the instrument had just been turned on.  On the contrary, the slop parameter randomly alters the tuning of each and every note.  This is not at all an accurate imitation of the actual vintage tuning problem.  So, I don't get all the hype over slop.
« Last Edit: September 25, 2016, 10:23:00 PM by Sacred Synthesis »

eXode

  • ***
  • 251
Re: The Prophet '08 Among Prophets
« Reply #261 on: September 26, 2016, 11:48:46 AM »
This is why I personally prefer the random approach that can be applied per voice, because it simulates the natural detuning that would occur between voices (or voice cards) on an older instrument, without introducing exaggerated drift, etc. To each his own but I love the effect from holding a chord and getting some natural detuning between the voices.

Sacred Synthesis

Re: The Prophet '08 Among Prophets
« Reply #262 on: September 26, 2016, 12:27:32 PM »
I should have written that my above comments concerned monophonic synthsesis.  I actually somewhat like the effect of a tiny amount of slop applied to polyphonic playing, and I do occasionally use it.  My point is, though, that the random and constant detuning of notes does not emulate the character of a vintage mono synth.  Whether or not one likes slop, it adds an effect that is quite different from the oscillator beating changes on a vintage instrument.  It's an attempt at vintage imitation as seen through the eyes of modern synthesis. 
« Last Edit: September 26, 2016, 12:43:22 PM by Sacred Synthesis »

Re: The Prophet '08 Among Prophets
« Reply #263 on: September 26, 2016, 01:52:43 PM »
My point is, though, that the random and constant detuning of notes does not emulate the character of a vintage mono synth.

There's no microprocessor in most vintage monophonic synths, so the notion of per-voice assignment / unison detune that changes per note couldn't and wouldn't happen. (Of course, one way to do this would be to pin the randomness values to individual oscillators, or alternately, have very-long-running LFOs to mimic a slow-drifting effect.)
Sequential / DSI stuff: Prophet-6 Keyboard with Yorick Tech LFE, Prophet 12 Keyboard, Mono Evolver Keyboard, Split-Eight, Six-Trak, Prophet 2000

Sacred Synthesis

Re: The Prophet '08 Among Prophets
« Reply #264 on: September 26, 2016, 02:05:08 PM »
What would accurately imitate the vintage analog character would be to offset to the slightest degree the keyboard tracking of one oscillator.  Then the relationship of the two oscillators would change ever-so-slightly as one ascended or descended the keyboard, thus effecting the beating rate.
« Last Edit: September 26, 2016, 02:07:59 PM by Sacred Synthesis »

eXode

  • ***
  • 251
Re: The Prophet '08 Among Prophets
« Reply #265 on: September 26, 2016, 02:07:06 PM »
I think the problem with slop, like I think have been touched upon already, has something to do with the frequency division and that is probably why you can never get a DCO with natural sounding drift.

It's the only logical explanation to me, as there is software out there today that is virtually indistinguishable from their hardware counterpart, and that emulates different VCO properties in a very realistic way.

That said, the Prophet 08 is still a fantastic instrument in it's own right, and offered at a very affordable price. I find it much more tempting than i.e. the upcoming Behringer synth (based on comparing features and interface alone).

Sacred Synthesis

Re: The Prophet '08 Among Prophets
« Reply #266 on: September 26, 2016, 02:12:56 PM »
That said, the Prophet 08 is still a fantastic instrument in it's own right, and offered at a very affordable price. I find it much more tempting than i.e. the upcoming Behringer synth (based on comparing features and interface alone).

Absolutely!  I'm not complaining at all about the Prophet '08.  I'm just trying to pinpoint a particular quality that so many folks like in VCO instruments.  The fact is, I don't like Slop at all for monophonic patches and would be fine without it altogether.  I only play around with it because it's there.  And I like DCOs specifically because they remain perfectly tuned in all registers.  I want the oscillator beating rate to be the same on the bottom octave as on the top, and DCOs achieve this.
« Last Edit: September 26, 2016, 02:15:25 PM by Sacred Synthesis »

eXode

  • ***
  • 251
Re: The Prophet '08 Among Prophets
« Reply #267 on: September 26, 2016, 02:15:22 PM »
That said, the Prophet 08 is still a fantastic instrument in it's own right, and offered at a very affordable price. I find it much more tempting than i.e. the upcoming Behringer synth (based on comparing features and interface alone).

Absolutely!  I'm not complaining at all about the Prophet '08.  I'm just trying to pinpoint a particular quality that so many folks like in VCO instruments.  The fact is, I don't like Slop at all for monophonic patches and would be fine without it altogether.  I only play around with it because it's there.  And I like DCOs.

Fwiw, I didn't think you were complaining. It's all good. :)

Sacred Synthesis

Re: The Prophet '08 Among Prophets
« Reply #268 on: September 26, 2016, 02:16:59 PM »
Gotcha.  ;D

Re: The Prophet '08 Among Prophets
« Reply #269 on: September 26, 2016, 03:47:41 PM »
I think the problem with slop, like I think have been touched upon already, has something to do with the frequency division and that is probably why you can never get a DCO with natural sounding drift.

It's the only logical explanation to me, as there is software out there today that is virtually indistinguishable from their hardware counterpart, and that emulates different VCO properties in a very realistic way.

I was wondering about that because the random modulation I'm applying to the oscillator frequency makes it sound "burbly" if that is indeed a word. I may be hitting the limits of the DCO frequency resolution. I suppose I could measure this resolution by using the mod wheel to modulate the Envelope 3 value modulating one of the oscillator frequencies. If I fix the other oscillator, I can nudge the mod wheel until I hear any evidence of beating. By measuring the beat frequency I should be able to determine the frequency resolution. To verify I should nudge the mod wheel again until I hear beating at a higher frequency. This frequency should be double the previous one.

I think I'll try to make this measurement. If the frequency resolution is the reason my tones are "burbly" then I should increase the modulation amount to make the effect more realistic. :-\

Re: The Prophet '08 Among Prophets
« Reply #270 on: September 26, 2016, 10:40:20 PM »
So I made the measurement. I played a D below middle C, which has a frequency of approximately 147 Hz. The minimum beat frequency I could generate was around 1/14 Hz or around .07 Hz. This gives a frequency resolution of around 0.04%. I'd expect that the total noise on the control voltage of a VCO would be in this ballpark, which would mean that the modulating a DCO with noise would not result in a normal frequency distribution as we'd expect with a VCO. Instead we'd get three spikes, one at 147 - 0.07 Hz, 147 Hz, and 147 + 0.07 Hz. Based on that I think that the DCO would have a lot of trouble sounding like a VCO just as eXode says. Darn!
« Last Edit: September 26, 2016, 10:43:13 PM by tumble2k »

Re: The Prophet '08 Among Prophets
« Reply #271 on: September 30, 2016, 01:14:00 AM »
The only vintage VCO-based polyphonic synth I've spent enough time with is the Jupiter 6. The one I have is surprisingly stable for a 30+ year old instrument.  The one thing I have noticed is the tuning/tracking of one voice is very slightly out with the rest. You don't really notice it when playing but it does give chords an extra bit of movement. Very subtle but it sounds gorgeous and very musical.

I personally find the P6 VCOs so stable as to offer no discernible benefits over DCOs. If anything, the P'08 has the edge as you can precisely fine tune both oscillators apart from each other. :)

Re: The Prophet '08 Among Prophets
« Reply #272 on: September 30, 2016, 07:14:36 AM »
When I dialed the output level down (to a very conservative value of 90) I found that the filter smoothed out quite considerably. Gone was the tendency to go instantly from too bright to muffled. The P'08 is definitely brighter than the P5 in the video, but in a nice modern way, as if the output stages aren't cutting everything off above 12kHz or so.

I opine that the bad rap the P'08 filter gets is due to the output clipping.

It turns out that the amp env amount can also cause clipping if it's set too high. If the system is clipping or is near clipping, it sounds subtly harder.

Re: The Prophet '08 Among Prophets
« Reply #273 on: September 30, 2016, 07:23:45 AM »
I personally find the P6 VCOs so stable as to offer no discernible benefits over DCOs. If anything, the P'08 has the edge as you can precisely fine tune both oscillators apart from each other. :)

Thanks for the information. I've been meaning to listen to a P6. I suspect it's impossible to hear the instantaneous variations in the pitch of a single VCO as small amounts of noise on the control voltage of the VCO cause it to trigger slightly randomly each cycle. However, if you combine that with another VCO that is also triggering with slight randomness, there might be something that's audible.

Last night I was playing around with extremely small amounts of random modulation on one oscillator while the other one was constant. I seem to be able to get lost in the sound a little better than without the modulation, but that's too subjective.

Re: The Prophet '08 Among Prophets
« Reply #274 on: October 09, 2016, 06:13:11 PM »
I hope this doesn't become tumble2k's Prophet '08 rant thread, but I thought I'd report on some more of my findings as I play with this amazing machine.

On slop:

I was playing the T8 Strings preset and tweaking it to my taste: enabling velocity sensitivity, disabling aftertouch, turning down the voice volume, which smooths out the filter, etc. When I was able to control it right I started playing some string pieces. Hmmm. Someone is playing out of tune. Is this high school orchestra? Oh yeah, slop! The slop was set to 2 or 3. I turned it to 0 and ... okay this sounds more professional! I think Sacred Synthesis said that slop recreates the worst quality of an old vintage synth, and I definitely agree.

On VCOs

I went to the local guitar center to play the Prophet 6 and the OB-6. The Prophet 6 struck me as an incredible keyboard. Everything I played sounded nice ... kind of the way a Moog always sounds nice. Very different from the '08! On the '08 you need to work for the good sounds. I have heard discussions about the sweet spot on the two instruments and now I understand what they mean.

Anyhoo ... I decided to take a careful listen to a single unadorned sawtooth and then a pair of sawtooths on the P6. I observed the following:

1. The single sawtooth on the P6 sounded pretty similar to the P'08's sawtooth, except it was maybe a little darker (but it could have been the sound system)
2. When there are two sawtooths running on the P6 with no detune, they always beat against each other. This is different than the P'08.

The same was true with the OB-6.

A bit discouraged, especially after my experiments with injecting noise into the DCO frequencies on the P'08 that turned out badly, I went home and played the P'08. Using a random LFO still sounded lumpy or burbly. On a whim I tried to use a reverse sawtooth LFO with a rate of 136 (about 120 Hz) and an amount of 1, the lowest possible.

Jackpot! The single sawtooth sounded pretty much the same. But when I combined two they tend to beat a little even with no detuning and no slop. The combined sound was very reminiscent of what I had heard from the Prophet 6.

I'm going to use the basic patch with these two LFOs, detune set to 0, and slop set to 0 as the starting point for my "VCO simulation" patches in the future.

I'm following mefistophelees's footsteps here. He said to experiment with rates and waveforms for the LFO. I think this works rather well. The reverse saw is a little like the ripple on a power supply (which is why I chose the LFO frequency of 120 Hz). I wonder if that has anything to do with anything.

Samples attached. First phrase is done with no detuning and no LFO modulation. The second phrase is done with a fair amount of detuning and no LFO modulation. The third phrase has no detuning and LFO modulation.
« Last Edit: October 09, 2016, 06:16:28 PM by tumble2k »

Re: The Prophet '08 Among Prophets
« Reply #275 on: October 10, 2016, 07:57:30 AM »
Two mistakes with my last post (I should probably create a new thread for this).

1. One of the oscillators in the example has no modulation.
2. The net effect of the LFO was to offset the DCO by a small positive amount. If I offset the oscillator by 6 or 7 cents negative the effect goes away.

I still haven't found a way to make the Prophet '08 DCOs sound like VCOs but I'll keep trying.

Re: The Prophet '08 Among Prophets
« Reply #276 on: October 10, 2016, 08:07:55 AM »
On slop:

I was playing the T8 Strings preset and tweaking it to my taste: enabling velocity sensitivity, disabling aftertouch, turning down the voice volume, which smooths out the filter, etc. When I was able to control it right I started playing some string pieces. Hmmm. Someone is playing out of tune. Is this high school orchestra? Oh yeah, slop! The slop was set to 2 or 3. I turned it to 0 and ... okay this sounds more professional! I think Sacred Synthesis said that slop recreates the worst quality of an old vintage synth, and I definitely agree.

That's funny. I always found that the slop parameter had only minimal impact that was barely noticeable. Definitely not to the point of anything being out of tune. Even in "The Definitive Guide to Evolver" the slop parameter is being described as subtle only, which made me - just like Anu Kirk writes of himself - set it to 5 by default.

This is also why - if I was going for that sort of effect - I always assigned two random (or random and triangle) LFOs at different speeds to each of the oscillators' pitch at an amount of 1. That gave me more slop than the slop parameter was able to produce.
« Last Edit: October 10, 2016, 08:25:34 AM by Paul Dither »

Re: The Prophet '08 Among Prophets
« Reply #277 on: October 10, 2016, 11:38:42 AM »
I looked up the slop amount for the T8 Strings patch. It was set to 3. I think that this is the setting where some may hear the oscillators as being out of tune. I certainly did. On a setting of 1 I can only hear the smallest amount of beating between to oscillators that have their fine values set to 0 so I don't expect that I'd hear the slop. It's also possible that the combination of detuning in the patch plus the slop put the frequency just in that range where it sounded "off." Additionally because I was playing classical music, my expectations for accurate pitch might have been more exacting.

Re: The Prophet '08 Among Prophets
« Reply #278 on: October 13, 2016, 10:56:00 PM »
tumble2k-

i tweaked the X-strings patch too.  Attached are a couple of examples.  It's just a test piece.  The performance is not that great, but i think it gives the flavor of an OB-X type string patch.  One is dry and the other has a little reverb and chorus added on for good measure.  Enjoy!  If you like it, I'll give you some of the tweaks I did.
Jim Thorburn .  Toys-  Dave Smith: Prophet 5, Rev 4; Prophet 08; Pro 2; Prophet 12 module; EastWest Orchestral soft synths; Yamaha S-90; Yamaha Montage 8, Yamaha DX-7; KARP Odyssey; Ensoniq ESQ-1.  All run through a Cubase DAW with a Tascam DM-24 board.

Re: The Prophet '08 Among Prophets
« Reply #279 on: October 14, 2016, 03:06:24 PM »
That does sound like an Oberheim string patch! I definitely would like to know the tweaks you did. Nice playing too.