Problem with Sub 37 (buzz sound)

gencomprodukts · Post by **gencomprodukts** » Mon Sep 08, 2014 8:59 pm

I just received my Sub 37 and it seems that i already have a problem

Indeed, there's a buzz sound in the spectrum of each oscillators between the square and triangle waves (nothing between the Square & pulse).
This annoying buzz sound is pretty loud on high KB octaves only and when i depress a key (it could be a problem with the VCA).
Prior testing my unit, i upgraded to firmware 1.0.3 but also sent the presets files for firmware 1.02 (sub37_presets_1_2.syx) as recommanded on the forum, so i was wondering if it could be a software issue?
Anyone with this buzz sound?
I need help.
Thanks.

gencomprodukts · Post by **gencomprodukts** » Mon Sep 08, 2014 10:34 pm

Audio file : https://dl.dropboxusercontent.com/u/975 ... nt%201.wav
As you can hear, it's pretty loud.
Never heard this "buzz" with my Sub Phatty.
Any help?

Updated message: 2nd audio file
https://dl.dropboxusercontent.com/u/975 ... nt%202.wav

EMwhite · Post by **EMwhite** » Tue Sep 09, 2014 10:50 am

Sounds perfectly normal to me, but I have Yamaha HS5 monitors so nothing fancy.

If you can scope the raw waveform (pre-filter), you'll see that when a triangle or even a sawtooth waveform flattens out, you get that buzz'ing; Try lowering the OSC volume and see if it's still present;

In modular, wave shapers and to some extent the original Moog CP3 mixer could overdrive waveforms to the edge of the normal voltage levels to the extent that clipping occurs. It's not the type of digital clipping that you experience when you push the amplitude of an audio signal beyond what an audio interface or mixing channel can handle, it's waveform clipping which as a rough hard edge to it.

At least, that's what I hear.

mmarsh100 · Post by **mmarsh100** » Tue Sep 09, 2014 12:32 pm

Sounds just like my Sub 37 and my Sub Phatty.

_DemonDan_ · Post by **_DemonDan_** » Tue Sep 09, 2014 1:18 pm

Hi gencomprodukts,

It's possible that you are clipping the signal somewhere (if not internally, then perhaps in an external mixer or amp).

Be sure that all your MIXER knobs are 12 O'Clock or less, the Feedback is all the way counterclockwise, and the MultiDrive is all the way counterclockwise.

Giving a synth the ability to distort in three different ways is awesome, but it comes with the additional responsibility of following the above three tips when you don't want distortion.

Also, some external meters on mixers or amps won't show correctly for simple pitches or certain frequency ranges, so it's possible to clip a preamp or amp without visual indication.

bartleby · Post by **bartleby** » Tue Sep 09, 2014 1:52 pm

gencomprodukts wrote:Audio file : https://dl.dropboxusercontent.com/u/975 ... nt%201.wav
As you can hear, it's pretty loud.
Never heard this "buzz" with my Sub Phatty.
Any help?

tbh, i don't hear any buzz there.

what i do hear however, at 00:13, is a strange and somewhat annoying artefact that i also noticed on my own s37: when sweeping the the osc wave knob between sawtooth and squarewave, the waveform doesn't morph as smoothly as it does between triangle and sawtooth. instead, near the 11 o'clock position of the knob, there is some kind of clicky jump.
this does not only occur when sweeping the knob, but also when sweeping the waveform via an lfo etc.
is this normal with this osc design?
can anything be done about it - other than try to avoid that part of the waveform sweep unless you want to hear some clicks?

gencomprodukts · Post by **gencomprodukts** » Tue Sep 09, 2014 2:01 pm

First thanks for your answers.
If you hear my audio file with headphones, you should see what i mean, don't u realy? No matter if the oscillators are all the way up or down 5, with or without multidrive (my recording is without, just the raw vco sound with the cutoff all the way opened, no resonance, nothing more), i have a constant buzz/hum sound in the spectrum and it's not the case with my Sub Phatty.
Unfortunately, in this state, i can't use the SUB37.
The strange thing is that it only comes between the Square & Triangle waves (starts below the square wave).
It is quite loud in high kb octaves (listen at 0:30 until the end of my file, it's is more evident on every notes).
Anyway, i've requested a return and replacement for another unit since it's defective for me (and i'm not a newbie with analog synths), it has been accepted but i will add another audio file in a few hours because maybe this one doesn't reflect what i want to explain.
I also have to mention that this buzzy sound comes not only when hearing the S37 with Headphones but also the Audio output, so for me it seems to be an issue with the vco or vca.
There's also some strange noises/artefacts in the spectrum when moving the waves that i have not with my Sub phatty (i'm not talking about the clipping between the waves, already discussed several times for the Sub phatty).

IgorCristo · Post by **IgorCristo** » Tue Sep 09, 2014 4:36 pm

The uncontinuous waveshape is related to the new oscillator design and one of the things I really hate about my Sub Phatty. I've asked this before here and someone from Moog did reply that this is normal behavior.

I don't hear any buzz... maybe it has something to do with your headphones or monitors. My 0.02.

gencomprodukts · Post by **gencomprodukts** » Tue Sep 09, 2014 7:08 pm

IgorCristo wrote: I don't hear any buzz... maybe it has something to do with your headphones or monitors. My 0.02.

No, unfortunately not. I've tried with professionnal headphones & monitors, asked to a friend to check with his monitors and the result is the same.

Here is my second audio file (please listen with headphones). I just hope you'll hear this buzz/hum sound this time

https://dl.dropboxusercontent.com/u/975 ... nt%202.wav

As i already said, i do have a Sub phatty and there's nothing like this with this new VCO core.
But if this strange behavior seems to be normal in your units, i will definitely ask for a refund

bartleby · Post by **bartleby** » Wed Sep 10, 2014 4:02 am

IgorCristo wrote:The uncontinuous waveshape is related to the new oscillator design and one of the things I really hate about my Sub Phatty. I've asked this before here and someone from Moog did reply that this is normal behavior.

that's what i feared - because both oscs on my s37 are behaving exactly the same way.

still i had been hoping, that there might be a trimpot or two in there that might help fix the issue.

JustABoy · Post by **JustABoy** » Wed Sep 10, 2014 6:51 pm

yes i get this too with a uk model. discontinuous between saw and pulse.
already swept this to good 'chipper' effect... sweeping from just above it, downwards to triangle. chzip chzip! admittedly not subtle, though.
im more bothered about the swiss cheese software. i can make it reliably lock up and permanently blaarrt when changing presets with the arp running.

gencomprodukts · Post by **gencomprodukts** » Thu Sep 11, 2014 7:40 am

JustABoy wrote:yes i get this too with a uk model. discontinuous between saw and pulse.
already swept this to good 'chipper' effect... sweeping from just above it, downwards to triangle. chzip chzip! admittedly not subtle, though.

Glad to see someone that can hear this buzzy sound. I'm not the only one and the phenomenon is worrying...
It is not subtle and i never got this behavior on non defective synths. Now, i'm afraid of a "normal behavior" with the S37

I just hope it's an issue.
Anybody else with the same behavior?

My unit is on the way for a replacement and i hope that the new one will not sound the same (clean vco's as with the SP), i'll let u now, but if this is not the case, bye bye S37

bartleby · Post by **bartleby** » Thu Sep 11, 2014 8:48 am

gencomprodukts wrote:
JustABoy wrote:yes i get this too with a uk model. discontinuous between saw and pulse.
already swept this to good 'chipper' effect... sweeping from just above it, downwards to triangle. chzip chzip! admittedly not subtle, though.
Glad to see someone that can hear this buzzy sound. I'm not the only one and the phenomenon is worrying...

uhm, sorry to disappoint you, but we were talking about a different issue.
we were talking about the annyoing discontinuity when morphing between sawtooth and square wave. there is a click there that doesn't belong there.
sorry for hijacking your thread. would probably have been worth a thread of its own...

@JustABoy: yeah i guess you could actually put this glitch to some good use with an eg or lfo deliberately triggering that discontinuity.

gencomprodukts · Post by **gencomprodukts** » Thu Sep 11, 2014 9:03 am

[/quote]
uhm, sorry to disappoint you, but we were talking about a different issue.
we were talking about the annyoing discontinuity when morphing between sawtooth and square wave. there is a click there that doesn't belong there.
sorry for hijacking your thread. would probably have been worth a thread of its own...
.[/quote]

No problem Bartleby but for sure another thread would be worth. This one is not taking about peaks between wave shapes already discussed (it's a normal behavior with the new vco core).

Amos · Post by **Amos** » Thu Sep 11, 2014 2:31 pm

JustABoy wrote:yes i get this too with a uk model. discontinuous between saw and pulse.
already swept this to good 'chipper' effect... sweeping from just above it, downwards to triangle. chzip chzip! admittedly not subtle, though.
im more bothered about the swiss cheese software. i can make it reliably lock up and permanently blaarrt when changing presets with the arp running.

the discontinuity between saw and pulse is a normal aspect of the continuous wave shaper. It's that way on the Voyager, the Little Phatty, the Sub Phatty and Sub 37. You can hear it better on the Sub 37 because we responded to a number of folks who requested brighter waveforms vs. the Voyager... so compared to the Voyager you can get a crispier high end out of the Sub Phatty and Sub 37... which also accentuates the discontinuity that is a normal part of the wave shaper.

As for the software locking up, are you running firmware v1.0.3 yet? This update fixes a lockup such as you describe.

Regarding the reported buzz sound, Moog engineering is taking this report very seriously and looking very carefully at all aspects of the oscillator design, to be sure it's behaving well. There's actually a Moog Model 15 modular on my desk at the moment, so we can compare the sawtooth from this classic instrument to the sound of the Sub 37. So far, all the things we have tested are performing correctly as designed. We have not conclusively proved that there is or isn't any extra harmonic content that isn't a natural result of a sawtooth running with filter cutoff greater than 20kHz... that's another thing about the Sub 37 versus Voyager and Little Phatty... the older instrument filters did not open up quite as wide as the Sub 37 does, so there is definitely more "stuff" in the top-end of the signal on the newer instruments, with the filter wide open. The thing that we are working on right now is making sure that all of that stuff is supposed to be there.

So far, so good, meaning that everything we've analyzed so far is indeed supposed to be there.

I don't want to say too much since this work is ongoing... just a note to say that we're taking your feedback seriously and working to make sure that everything is as good as it can be.

Cheers,

Amos

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