The noise source for this machine is a MM5837N which internally is a 17 bit digital linear feedback shift register with a single feedback tap. x^{{17}}+x^{{14}}+1 Feedback length of 131,071 This will sound like pseudo random noise in short bursts but will repeat every 131071 clock cycles. This is the cyclic sound that you are hearing.
In fact, the Prophet5's noise generator is digital, and it was implemented using an MM5837 chip (which is basically a Linear Feedback Shift Register). Best Regards!
The "looped effect" is typical of noise generators that use a shift register: the duration of the loop depends on the number of bits the shift register is composed of and the clock rate that drive the IC. Your Prophet is ok.
In order to get a pure square waveform, the pulse width adjustment needs to be exactly at 50%. Anything else will sound like a pulse wave, and not a square wave.
@@rootstudio247 The Moog Rogue doesn't have a pulse width adjustment knob. On the waveform selector switch, OSC1 has a fixed 50% duty cycle (square waveform) and OSC2 offers 85% duty cycle (pulse waveform).
2:25 - is there a musical term for what he is doing here; this ascending scale? I'm sure there is... I'm sure I used to know it, but it's completely gone!
@@rootstudio247 Thanks. Possibly, but that's certainly not the word/description/term I was thinking of. I should have written it down years ago when I saw it. To be accurate, it's the ascending scale of notes played by Francis Monkman at the 30 second mark on sky's version of Toccata.
Someone else mentioned the extra noise in the square wave which I think is a factor, but the rounded corners I think are bigger - the sharper the corner, the stronger the really high upper harmonics. I bet the top end of the filter is just a little lower even when wide open, that usually rounds off the corners just like that. While the noise probably helps it sound a little less “clinical”, it definitely audibly lacks the very high “squeal” present in the Moog which definitely makes it sound more brittle. Edit: could also be a finely tuned slew control, since it is a very perfect rounded corner. Same overall effect on the harmonics though! Maybe slightly more complex partials… perhaps that’s part of the Prophet Magic.
@@rootstudio247 I’ve noticed a lot of early modulars had very round square and triangle waves too, both sounding more like a sine wave with just a slight hint of their shape character. Which sound a bit underwhelming on their own but often IMO sound better in a composition than very precisely-shaped oscillators. The Prophet is more distinct than those for sure, but they clearly took care in not going “too” perfect.
I am only a beginner,one observation I have noted was we often know what we don't want in a sound,yet do not know exactly what we do want,instantly knowing what isn't for us,and what is without knowing why.
First, all my thoughts and good vibes to Dave Smith, wherever he is now. He inspired so many and shaped the synth world so much.. In the re-issue of the prophet, they've added a three-way switch for the filter's keyboard tracking (off, half, full). It's not as powerful as let's say the "keyboard" knob on a moog matriarch, but it really does the job and gives you a ton of flexibility. The differences between "half" and "full" tracking, compared to no tracking at all, are really opening a new world in terms of patching, playing and sound. You're absolutely right to mention this is a real miss on the original P5, they corrected that over the years it seems! As for the square waves differences between the prophet and moogs in general, I definitely agree, the prophet has a more "pleasant" character to it, mostly because it has a bit more depth and randomness. Looking at your waveforms, maybe that amount of extra noise helps there, compared to a moog which might be a bit further from the expected waveform, and has a tendency to be and sound a bit clearer, and therefore a tiny bit less enjoyable and harsh to the ears. And the noise, I'm still relatively new to Prophet town, got my 10 reissue quite recently, and I haven't caught that, so thanks for enlightening us! I guess it's not that much of a bummer, noise is mostly used sparsely and at low levels with poly synths, filters are more often closed than wide open, so I guess a looping pattern becomes less obviously audible most of the times... but now I know that if I want presence for some noise, I'll stick to the moogs to let that happen! Thanks for sharing your findings, if that's all there is with a prophet, I'll still be very happy and thankful to have one right next to me then :)
Edit..: I just checked on the P10 Rev 4, and there's no audible pattern in the noise generator, I guess they changed that too...which would make total sense in 2020... i'll try to find what chip they're using, but I guess it's a bit smarter than the original, years have passed...
I seem to tremember that on the Prophet '08 the noise was digital. I guess it was an inheritance of the Evolver series, which had 2 analog and 2 digital oscs. So perhaps they borrowed some of the structure of the Evolver to implement noise generation on the '08. It doesn't seem completely unlikely that they did the same thing on the P5.. but that loop point is very poorly chasen indeed!
@@rootstudio247 Yeah I saw that just after I posted I have a 3.3 I've noticed uncertain pieces of equipment I can hear the operation noise through my amps things like that
@@rootstudio247 My Waldroff blofeld kicks out of bunch of noise When I have the game turned all the way up on my Baranger keyboard app Open grounds in an old house I Live in might have something to do with it too
I like that kind of videos, thanks! I would be happy to get more of these kind of videos about the Prophet 5/10 synthesizer. I have the Prophet 10 Rev4 and will try to find about it if it is the same with my Prophet. I will take my time to check it because my synthesizer are stored in cases, I have a small flat and I am no musician but of course I love the creation of music and especially the sound and flexibility of the Prophet 10. If you are interested then I could write about my results later but please be patient with me 😉
Can you upload a longer sample of the moog noise oscillator? Perhaps its my imagination, but I kinda hear a periodicity in it: `taptaptap..tap`, `taptaptap..tap`.
From the front panel control layout including the tape buttons on the top right of the panel, I'm guessing your P-5 is a rev 3 of some kind. My rev 3.3 noise does have a very slight looping effect like yours but is far less pronounced, "almost" imperceptible to hear. I do have the Rev-1 filter mod on her so maybe the filter noise is being smoothed out? No idea, but if other comments say it's normal, I certainly would believe that it's just a function of components, age, and the technology of 1978-83. Every analog synth has it's quirks. ;)
The noise source for this machine is a MM5837N which internally is a 17 bit digital linear feedback shift register with a single feedback tap.
x^{{17}}+x^{{14}}+1 Feedback length of 131,071
This will sound like pseudo random noise in short bursts but will repeat every 131071 clock cycles. This is the cyclic sound that you are hearing.
Thanks 😊
Dang.
In fact, the Prophet5's noise generator is digital, and it was implemented using an MM5837 chip (which is basically a Linear Feedback Shift Register). Best Regards!
Cool, thanks! Now it would be nice to know if it is supposed to sound like that or if mine has a problem.
The "looped effect" is typical of noise generators that use a shift register: the duration of the loop depends on the number of bits the shift register is composed of and the clock rate that drive the IC. Your Prophet is ok.
@@lucaxyz8938 Thanks again! At least now I know that it's not a faulty chip. I'm happy with that and I'
m not going to replace it 🙂
@@rootstudio247 Wise choice: if it was mine, I would do the same and keep it original. Have fun!!!
Thanks for the explanation. Very interesting!
You might want to check out the new Prophet 5 … both the noise source and the filter tracking issues are resolved
Yes, that and then some 😃
The Rev 4 still has that 0 - 50 -100% button.
Yes, I believe that’s what Paul Schilling above referred to 👍
Cool vid! Interesting stuff with the different wave forms.
Thank you 😊
Nice comparison P5 vs Rogue ... Thanks
Thanks 😊
In order to get a pure square waveform, the pulse width adjustment needs to be exactly at 50%. Anything else will sound like a pulse wave, and not a square wave.
Yes of course! I definitely made sure it wad 50%. You can easily train your ears to tell when it is square.
@@rootstudio247
I'm sorry but my trained ears tell me that the P5 is not precisely adjusted to get a 50% duty cycle. The Moog is.
@@AlainHubert interesting! Still the Prophet sounds better to me, no matter where I put the Moog‘s knob. There must be more to this.
@@rootstudio247
The Moog Rogue doesn't have a pulse width adjustment knob. On the waveform selector switch, OSC1 has a fixed 50% duty cycle (square waveform) and OSC2 offers 85% duty cycle (pulse waveform).
2:25 - is there a musical term for what he is doing here; this ascending scale? I'm sure there is... I'm sure I used to know it, but it's completely gone!
You could call this an arpeggio, although generally you'd expect an arpeggio to at least contain thirds also, not just octaves and fifths.
@@rootstudio247 Thanks. Possibly, but that's certainly not the word/description/term I was thinking of. I should have written it down years ago when I saw it. To be accurate, it's the ascending scale of notes played by Francis Monkman at the 30 second mark on sky's version of Toccata.
@@blastfromthepast-o1d Glissando? Do you have a link? I can’t find that thing.
@@rootstudio247 th-cam.com/video/QgbgUrp1a70/w-d-xo.html
Someone else mentioned the extra noise in the square wave which I think is a factor, but the rounded corners I think are bigger - the sharper the corner, the stronger the really high upper harmonics. I bet the top end of the filter is just a little lower even when wide open, that usually rounds off the corners just like that.
While the noise probably helps it sound a little less “clinical”, it definitely audibly lacks the very high “squeal” present in the Moog which definitely makes it sound more brittle.
Edit: could also be a finely tuned slew control, since it is a very perfect rounded corner. Same overall effect on the harmonics though! Maybe slightly more complex partials… perhaps that’s part of the Prophet Magic.
It’s definitely part of the magic. Which other synth would use the square wave for its strings preset?
@@rootstudio247 I’ve noticed a lot of early modulars had very round square and triangle waves too, both sounding more like a sine wave with just a slight hint of their shape character. Which sound a bit underwhelming on their own but often IMO sound better in a composition than very precisely-shaped oscillators. The Prophet is more distinct than those for sure, but they clearly took care in not going “too” perfect.
I always thought that triangle waves were redundant, because they’re basically just filtered squares.
I am only a beginner,one observation I have noted was we often know what we don't want in a sound,yet do not know exactly what we do want,instantly knowing what isn't for us,and what is without knowing why.
Yes, that’s what keeps the soundware industry going 😊
First, all my thoughts and good vibes to Dave Smith, wherever he is now. He inspired so many and shaped the synth world so much..
In the re-issue of the prophet, they've added a three-way switch for the filter's keyboard tracking (off, half, full). It's not as powerful as let's say the "keyboard" knob on a moog matriarch, but it really does the job and gives you a ton of flexibility. The differences between "half" and "full" tracking, compared to no tracking at all, are really opening a new world in terms of patching, playing and sound. You're absolutely right to mention this is a real miss on the original P5, they corrected that over the years it seems!
As for the square waves differences between the prophet and moogs in general, I definitely agree, the prophet has a more "pleasant" character to it, mostly because it has a bit more depth and randomness. Looking at your waveforms, maybe that amount of extra noise helps there, compared to a moog which might be a bit further from the expected waveform, and has a tendency to be and sound a bit clearer, and therefore a tiny bit less enjoyable and harsh to the ears.
And the noise, I'm still relatively new to Prophet town, got my 10 reissue quite recently, and I haven't caught that, so thanks for enlightening us! I guess it's not that much of a bummer, noise is mostly used sparsely and at low levels with poly synths, filters are more often closed than wide open, so I guess a looping pattern becomes less obviously audible most of the times... but now I know that if I want presence for some noise, I'll stick to the moogs to let that happen!
Thanks for sharing your findings, if that's all there is with a prophet, I'll still be very happy and thankful to have one right next to me then :)
Edit..: I just checked on the P10 Rev 4, and there's no audible pattern in the noise generator, I guess they changed that too...which would make total sense in 2020... i'll try to find what chip they're using, but I guess it's a bit smarter than the original, years have passed...
Good stuff - thanks for sharing your findings. This is great feedback 👍
Yep, a welcome upgrade without messing with the original in any substantial way.
I seem to tremember that on the Prophet '08 the noise was digital. I guess it was an inheritance of the Evolver series, which had 2 analog and 2 digital oscs. So perhaps they borrowed some of the structure of the Evolver to implement noise generation on the '08. It doesn't seem completely unlikely that they did the same thing on the P5.. but that loop point is very poorly chasen indeed!
Maybe the sound is caused by the tracking of the SZ80 Processor on the keyboard Scanning it being picked up by the circuit Or something like that
Actually, it’s by design as Luca XYZ pointed out in his comment. So at least all rev3 synths can be expected to sound like this.
@@rootstudio247 Yeah I saw that just after I posted I have a 3.3 I've noticed uncertain pieces of equipment I can hear the operation noise through my amps things like that
Yep, especially with unbalanced connections!
@@rootstudio247 My Waldroff blofeld kicks out of bunch of noise When I have the game turned all the way up on my Baranger keyboard app Open grounds in an old house I Live in might have something to do with it too
Old wiring certainly can add noise, e.g. ground loops.
I like that kind of videos, thanks! I would be happy to get more of these kind of videos about the Prophet 5/10 synthesizer. I have the Prophet 10 Rev4 and will try to find about it if it is the same with my Prophet. I will take my time to check it because my synthesizer are stored in cases, I have a small flat and I am no musician but of course I love the creation of music and especially the sound and flexibility of the Prophet 10. If you are interested then I could write about my results later but please be patient with me 😉
Great, please share your findings.
Does the Prophet 5/10 rev 4 use SMT or is it still through-hole?
SMT
@@rootstudio247 thank you!
Can you upload a longer sample of the moog noise oscillator? Perhaps its my imagination, but I kinda hear a periodicity in it: `taptaptap..tap`, `taptaptap..tap`.
That is just your desire to hear some pattern. It is totally random.
Still want to see you talk about that polymod section.
Hope I get a chance to do that, thanks 🙂
From the front panel control layout including the tape buttons on the top right of the panel, I'm guessing your P-5 is a rev 3 of some kind. My rev 3.3 noise does have a very slight looping effect like yours but is far less pronounced, "almost" imperceptible to hear. I do have the Rev-1 filter mod on her so maybe the filter noise is being smoothed out? No idea, but if other comments say it's normal, I certainly would believe that it's just a function of components, age, and the technology of 1978-83. Every analog synth has it's quirks. ;)
Yes, but the odd thing is that it’s actually a digital noise generatior. Live and learn 😀
@@rootstudio247 indeed…. I’ve had my Prophet since 1986 and never knew it myself until this video.
@@drsamurai009 great 😊 mine is a Rev 3.0 btw.
I got it for my birthday present
Good for you! That’s the best way to get one 💪
RIP Dave Smith
❤️❤️
❤️❤️