The Official Sequential/Oberheim Forum

SEQUENTIAL/DSI => Prophet-5/Prophet-10 => Topic started by: engineerjoel on May 26, 2022, 01:29:16 PM

Title: Noisy P5/10...Please Listen to MP3 file
Post by: engineerjoel on May 26, 2022, 01:29:16 PM

Prophet 5/10 Rev 4

Please listen to the attached .mp3 file.

With all Oscillator waveforms turned off and both Osc volumes (including Noise) turned down, you can still hear background information when I play the keys.   

You can hear me sweeping through both Oscillator's frequency knobs; then, you hear me turn up/down the Cutoff frequency.    It's pretty noticeable even with the Master Volume is about 10:00.

Anyone else hearing this phenomenon? 

Title: Re: Noisy P5/10...Please Listen to MP3 file
Post by: LPF83 on May 27, 2022, 05:09:49 AM

Prophet 5/10 Rev 4

Please listen to the attached .mp3 file.

With all Oscillator waveforms turned off and both Osc volumes (including Noise) turned down, you can still hear background information when I play the keys.   

You can hear me sweeping through both Oscillator's frequency knobs; then, you hear me turn up/down the Cutoff frequency.    It's pretty noticeable even with the Master Volume is about 10:00.

Anyone else hearing this phenomenon?

Yes, I hear it on my P10...  Oddly it seems to stop if I switch to Rev 1/2 mode from Rev 3, or if I toggle off "Preset"
Title: Re: Noisy P5/10...Please Listen to MP3 file
Post by: HockeBocke on May 27, 2022, 06:26:11 AM
Aaah ...  They try to replicate the leakage noice from old tonewheel Hammond's    ::)

But seriously, why playing the keys with sound off ?  Are you using the P-10
as a MIDI controller and that noice is heard on P-10's track when recording, or .... ?

Just curious about when this noice is an issue IRL ....

( My old DX7 MK1 is another story regarding noice / hiss ....    Cheesus Chrysler !   :o  )


Cheers !
Title: Re: Noisy P5/10...Please Listen to MP3 file
Post by: LPF83 on May 27, 2022, 07:17:18 AM
Aaah ...  They try to replicate the leakage noice from old tonewheel Hammond's    ::)

But seriously, why playing the keys with sound off ?  Are you using the P-10
as a MIDI controller and that noice is heard on P-10's track when recording, or .... ?

Just curious about when this noice is an issue IRL ....

( My old DX7 MK1 is another story regarding noice / hiss ....    Cheesus Chrysler !   :o  )


Cheers !

Well if nothing else, even if it is intentional it represents an interesting difference between Rev 1/2 and Rev 3 filter types that doesn't appear to be documented elsewhere, such as the fact one mode produces a saw wave and the other a ramp on init patch.  My first thought was maybe the Rev 3 had a higher noise floor than Rev 1 so they're being true to the original but that wouldn't explain why it disappears when the Preset button is toggled off.

I consider a certain amount of noise "normal" in analog synths (at times maybe even desirable), but I do think when present the cause for it should be identifiable.  Any amount of noise will get added into the individual harmonics and thus impact the overall tone of a synth in some ways.

Title: Re: Noisy P5/10...Please Listen to MP3 file
Post by: h4ndcrafted on June 21, 2022, 06:58:52 AM
Just checked my P5 , no I don’t have this at all, even when turning up max , I hear nothing right up to where the noise floor starts on my ssl six. Which is quite high up.
Title: Re: Noisy P5/10...Please Listen to MP3 file
Post by: LPF83 on June 21, 2022, 04:14:02 PM
I tried this again today and was not able to reproduce anything like your MP3, just a slight increase in what I consider "normal" analog noise (around -85db or so).  I did notice some noise when I was in manual mode (preset light off) with oscillators off and I didn't notice that the resonance was set high enough that it was starting to self oscillate but that was easily solved once I realized what was going on. 

@engineerjoel have you eliminated filter self-oscillation as the culprit? (set resonance to zero).
Title: Re: Noisy P5/10...Please Listen to MP3 file
Post by: maxoreilly on February 13, 2024, 09:34:35 PM
Did you ever find a resolution to this? I am having the exact same issue with mine! Never experienced this before in a synth.
Title: Re: Noisy P5/10...Please Listen to MP3 file
Post by: Manbird on February 13, 2024, 10:00:12 PM
Did you ever find a resolution to this? I am having the exact same issue with mine! Never experienced this before in a synth.

I've never had an issue with noise, but I'm happy to see Wasp Star represented for the only time ever on this forum!
And keeping things slightly on topic... English Settlement is one of the classic Prophet 5 albums, eh wot?!
Title: Re: Noisy P5/10...Please Listen to MP3 file
Post by: Ncapone on February 16, 2024, 08:12:20 PM
Unlike some others, my Prophet 10 does not do this.
Title: Re: Noisy P5/10...Please Listen to MP3 file
Post by: gus on February 22, 2024, 01:07:06 PM
It sounds like the file is normalized, or has had the gain adjusted to be quite high?

The noise floor on our synths is generally around -80dB. We recommend keeping the master volume at max, feeding an unbalanced line level input on a mixer/interface for best results.

Some noise is expected on the P5/10 given the density of analog components in the signal path. Even with the oscillators off (as is the case in the recording), you will still hear some bleed and noise as the VCA's open up. This is normal and shouldn't be a cause for concern, especially at normal playing volume. At the end of the day... it's analog!

If anyone still has issues with this, feel free to reach out to support@sequential.com and we can help you out.
Title: Re: Noisy P5/10...Please Listen to MP3 file
Post by: 558 on February 23, 2024, 05:02:23 AM

Prophet 5/10 Rev 4

Please listen to the attached .mp3 file.

With all Oscillator waveforms turned off and both Osc volumes (including Noise) turned down, you can still hear background information when I play the keys.   

You can hear me sweeping through both Oscillator's frequency knobs; then, you hear me turn up/down the Cutoff frequency.    It's pretty noticeable even with the Master Volume is about 10:00.

Anyone else hearing this phenomenon?

Sometimes I am able to get a reverby/phasery or other sort of effect when I have the pw LFO mod on.  Is the pw lfo mod on?  It sounds like one of those times.  I must have dozens of memories of times I have used this to get a sound with almost a reverb when there was none.  Can't remember the specifics of course.  Sounds like one of those though.  Sometimes you turn off the PW Mod LFO and it comes back a different sound.  Just cause the oscs are turned down doens't mean the filter's not on.  Tons of sounds with just filter.  You seem new.  A lot of people seem to think they are having problem but they are reall not. This a good sound you put up.  Very phaser.

After all there is a whole section of the synth just for filter.  You will find a lot of sounds with the oscillators turned down and or the wave forms off.  You will find a lot of sounds are a screaming ringing filter shaped different ways.  A lot of those bells you hear are pure filter.  There's just a ton of noise in this thing man.