URGENT!!!! Some digital sound leaking in my p12 patches.

The Dave Smith Instruments Prophet-12 Analogue Synthesizer

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RobbaSvenna
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by RobbaSvenna » Mon Aug 04, 2014 8:37 am

Hi Sylvain!

I'm aware that this forum isn't run directly by DSI (I'm a long time Tempest owner and member of this forum), but I voiced my agony here to see if any other users had this problem as severe as I do.
I e-mailed the DSI Support last night and I hope they can help me. I've dealt with them before, and they are very helpful indeed!

I hope there is "just" something wrong with the hardware on my unit, because without the 11k-noise this is the best damn synth I've ever played or heard!

Kermit
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by Kermit » Mon Aug 04, 2014 9:30 am

Of course I mailed Mark at the support at first!

...but I thought this forum was kinda´like the DUC (pro tools user forum) where people from Digidesign used to "hang".

The "hello DSI and please DSI" expressions will end from now on.

Thanks for telling me, so Pym won´t have a nervous breakdown. ;-)

But....I´m shure other p12 owners should be warned and aware about a problem like this. And the only way to get to other p12 users would be thru a forum so at least I will continue posting what I think is urgent matters about the p12.

Ah whatever, let´s stick to the topic so that other people with a 11kHz spike can and will be aware of a not acceptable thing for a 2650€ machine.

/Johan
silvain wrote:Hey Kermit and RobbaSvenna,
this forum is not run by DSI. Again a big thanks to our obscure and very quiet host!
Pym - developer for DSI - tries to keep up with bugs announced here. But if you find such things, best e-mail the support on davesmithinstruments.com and tell them. As we've seen they are good about replacing faulty hardware.

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silvain
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by silvain » Mon Aug 04, 2014 10:53 am

Yes, this forum is the place to reach a nice user base Kermit and Pym does read it. Only with so much going on here, there's no guarantee that he or other DSI employees will read something.
So please don't stop posting problems and even suspected hardware bugs! When confirmed, just remember to always send an e-mail to DSI support.

Kermit
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by Kermit » Mon Aug 04, 2014 12:25 pm

Great!! :-)

I´ll keep everyone updated on what the support says about this little thing that makes, at least mine, the p12 unusable.
silvain wrote:Yes, this forum is the place to reach a nice user base Kermit and Pym does read it. Only with so much going on here, there's no guarantee that he or other DSI employees will read something.
So please don't stop posting problems and even suspected hardware bugs! When confirmed, just remember to always send an e-mail to DSI support.

MakesSynthToMe
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by MakesSynthToMe » Mon Aug 04, 2014 1:32 pm

I've always thought this was just noise through my interface, but after going through the post here, I disconnected from it and went directly to two different pairs of monitors and a couple pairs of headphones, and it was still there. Its more pronounced on a set of 3 series JBL's and my AT M50's. Will be waiting to see what the response is from DSI. It does seem to be on just about all patches, but more emphasized on some.

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Fuseball
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by Fuseball » Mon Aug 04, 2014 2:50 pm

On Kepler, try turning off all the delays (Amount = 0). On my P12 the 11kHz spike drops dramatically when the delays are taken out of the mix. In fact all it takes is one delay to be active for the 11kHz spike to be more pronounced. Bringing down the active delay's LP Freq also reduces the spike, presumably because there's no signal from the delay still getting through to the mix.

Whilst I don't think the 11kHz spike is entirely down to the delays (it's still visible when viewed in Live's Spectrum), I think it is getting greatly amplified by the digital delay implementation.

Does anyone else get the same behaviour?
Prophet'08 PE #3591 | Tetr4 #2088 | MEK PE #1180 | Jupiter 6 | Juno 60 | Moog Sub Phatty | MS-20 mini | random digital stuff

AlanC
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by AlanC » Mon Aug 04, 2014 3:05 pm

Part of the problem is that the amount of 11kHz noise can vary wildly depending on the patch. When my P12 is set to the basic patch with no notes being played the noise is down around -102dB which is below that of my audio interface.

On the other hand, here's the worst example I found while experimenting: a "bowed string" patch playing a bass note. Note there is absolutely no EQ (or any other FX) being applied here.

Image

The 11kHz peak is approximately -36dB down from the fundamental. :shock:

So while it looks like some P12's are worse than others, particular patches can greatly exaggerate the peak.

Fuseball: Yes, I've noticed that the delays can exaggerate the peak.

Pym
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by Pym » Mon Aug 04, 2014 3:10 pm

Yeah, you've contacted support so there isn't much I can add. They'll take good care of you.

I'll be posting an OS update soon
Chris Hector
https://soundcloud.com/iampym
Dave Smith Instruments

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silvain
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by silvain » Mon Aug 04, 2014 3:41 pm

I can confirm the delays being noisy. I tried the Kepler and a few others. Interestingly my own patches don't suffer from it in the same way, although I use delays quite often, if only to boost the stereo width.
I also noticed that the headphones out has a worse sound -> bleeding ratio than the line-outs. Maybe something to do with my interface though.

RobbaSvenna
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by RobbaSvenna » Mon Aug 04, 2014 5:14 pm

Pym wrote:Yeah, you've contacted support so there isn't much I can add. They'll take good care of you.
Still I believe it would be greatly valued and interesting to hear your (as the software developer) opinion on this "11k-noise" that seem to exist on a lot of paying customers units. I'm for example intrigued if the DSI Team heard this during the development, and are aware of the problem etc.
Though I understand if it's hard for you to make a statement about it here.

Anyway, I'm still awaiting a response from the support.

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Fuseball
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by Fuseball » Mon Aug 04, 2014 5:36 pm

Razmo wrote:Has anyone tested, if this 11Khz peak is more pronounced when the delay volume is turned up or down?... and if it gets worse when messing with the tuned feedback as well?
Turning the delay volume up definitely boosts the volume of the 11kHz peak. Tuned feedback doesn't appear to make any difference as far as I can tell.
Prophet'08 PE #3591 | Tetr4 #2088 | MEK PE #1180 | Jupiter 6 | Juno 60 | Moog Sub Phatty | MS-20 mini | random digital stuff

Kermit
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by Kermit » Mon Aug 04, 2014 6:00 pm

+1
RobbaSvenna wrote:
Pym wrote:Yeah, you've contacted support so there isn't much I can add. They'll take good care of you.
Still I believe it would be greatly valued and interesting to hear your (as the software developer) opinion on this "11k-noise" that seem to exist on a lot of paying customers units. I'm for example intrigued if the DSI Team heard this during the development, and are aware of the problem etc.
Though I understand if it's hard for you to make a statement about it here.

Anyway, I'm still awaiting a response from the support.

AlanC
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by AlanC » Mon Aug 04, 2014 6:42 pm

Perhaps someone could check the following:

Certain delay times used in conjunction with feedback will greatly emphasise the 11kHz peak. A Delay Time value of 36 is a notable culprit: I can get the peak up to about -66dB with no notes playing if the amplitude and feedback are both high.

But there's an easy solution: on the Delay Filter tab, set the LP Freq to 126 (instead of the default 127). On my P12 this immediately drops the 11kHz peak down to about -90dB.

AlanC
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by AlanC » Mon Aug 04, 2014 7:11 pm

Now this is odd. The filter works a treat on my string patch that had the massive peak in the image I posted above, but it doesn't work on the Kepler patch, and turning all the delay amounts to zero only pulls the peak down about 2-3dB.

Razmo, I'm not sure I see how it could be the ADCs or DACs. Most of the time the 11kHz peak on my P12 is -96dB or less. Some patches (e.g. Kepler) can pull it up to about -78dB, and that one patch where the delay apparently got tuned to the peak pulled it up to -66dB so it's not remotely consistent, which I would have expected if it was a problem with the converters.

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Fuseball
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by Fuseball » Mon Aug 04, 2014 7:31 pm

AlanC wrote:Perhaps someone could check the following:

Certain delay times used in conjunction with feedback will greatly emphasise the 11kHz peak. A Delay Time value of 36 is a notable culprit: I can get the peak up to about -66dB with no notes playing if the amplitude and feedback are both high.

But there's an easy solution: on the Delay Filter tab, set the LP Freq to 126 (instead of the default 127). On my P12 this immediately drops the 11kHz peak down to about -90dB.
Delay times of 39, 46 and 54 are emphasising the 11kHz peak here. It reaches -80db with those settings but other delay times go as low as -97db.

Setting the delay's LP Freq to 126 drops mine from roughly -80db to -98db. The ratios seem pretty similar between our P12s. Certainly, that little bit of filtering appears to regulate the 11kHz peak so it is at least more consistent between delay times.

This was just using the Basic Patch. Sounds like its behaviour is inconsistent.

As you say, Razmo, it's all speculation at the moment.
Prophet'08 PE #3591 | Tetr4 #2088 | MEK PE #1180 | Jupiter 6 | Juno 60 | Moog Sub Phatty | MS-20 mini | random digital stuff

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elmquist
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by elmquist » Mon Aug 04, 2014 7:53 pm

And some pretty clear sighted instrument debugging. I am impressed by your analysis and findings! :-)

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BobTheDog
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by BobTheDog » Mon Aug 04, 2014 8:08 pm

I read somewhere that the 11K signal is due to the modulation system which runs at 11K, so maybe patches with heavy use of the modulations have higher noise.

Maybe the delays are also working at this 11K rate?

RobbaSvenna
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by RobbaSvenna » Mon Aug 04, 2014 8:56 pm

So, I did some more trouble shooting and I think at least my P12 have something wrong with the voices. This is what I did:

I created a Basic Patch from the Global Menu and selected a Sine. Then I started on Voice 1 and ended with Voice 12 doing a filter sweep on each voice. On Voice 1 the noise-spike I mentioned earlier is barely audible (however there is still some extremely high-pitched noise present) but as I cycle through the voices towards Voice 12 the digital noise spike gets louder, louder and louder until it gets unbearable.

http://hyperheart.com/SineVoiceCycling.wav

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elmquist
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by elmquist » Mon Aug 04, 2014 9:02 pm

RobbaSvenna wrote:On Voice 1 the noise-spike I mentioned earlier is barely audible (however there is still some extremely high-pitched noise present) but as I cycle through the voices towards Voice 12 the digital noise spike gets louder, louder and louder until it gets unbearable.
Interesting! Wonder if it could it be a hardware noise problem from either the power supply box or the main processor?

AlanC
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Re: URGENT!!!! Some digital sound leaking in my p12 patches.

Post by AlanC » Mon Aug 04, 2014 9:35 pm

BobTheDog wrote:I read somewhere that the 11K signal is due to the modulation system which runs at 11K, so maybe patches with heavy use of the modulations have higher noise.
I remember that one as well, but it doesn't seem to be true for waveshape modulation, at least, because I've got several patches where each of the four LFOs is modulating the corresponding oscillators shape, and that doesn't seem to increase the peak much, if at all.

The only times I've seen the peak go above about -80dB on my particular P12 is when the delay lines have been tuned so they resonate and reinforce that frequency, and the occasional patch here and there of which Kepler is probably just about the worst example.

RobbaSvenna: You haven't just got a peak at 11kHz, you've got double peaks at around 4kHz and 7kHz as well, that increase in amplitude as you step through the voices:

Image

If you haven't sent that file to DSI Support then I think it'd be a very good idea to do so, because there seems to be something very badly wrong with your P12.

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