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Roland JP 8080 DC Offset with the Supersaw OSC
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| Eric J |
Anyone else seen any problems with the JP8080 having a large DC Offset when using the Supersaw Oscillator?
It seems to me that when I record a pattern on a patch using the Supersaw oscillator and the filter is around 75% open, the DC offset is pretty large, especially if I make sudden movements on either the filter or amp envelopes using a MIDI CC message.
Anyone else seen this behavior? |
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| Eldritch |
| This is perfectly normal for heavily detuned sounds. My Virus TI Hypersaw does the same thing. |
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| johno27 |
| Are you getting a continuous DC offset through-out the sound? (IE: can be removed from the sequencer/audio editor's remove DC offset function) or is it more like what we were discussing in the other thread re: my insanely odd saw/supersaw problem? |
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| johno27 |
| Are you sure this is DC offset? and not the same problem I was/am having? If it were DC offset I would be able to use Logic's "Remove DC Offset" feature to fix it, which doesn't seem to work. Eric did you try that? |
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| Eric J |
Yeah, I tried remove DC Offset and it doesn't help at all. The weird thing is that it is only present then the filter is more than 50% open and the amp sustain is set to almost full.
When I'm doing a filter sweep from 0% to 75% the offset appears at about the 50-65% mark. In addition, right at that point, I do a sudden amp sustain increase from about 20% open to about 80% open.
So it is not continuous, but right after the amp sustain change.
Eldritch may be right, it just may be a fact of hevily detuned sounds. by saw detune at around 60%. |
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| johno27 |
I seriously think we're onto something here.. This is very similar to what was happening with my jp8080 patches that are giving me so much grief in the other thread.
Granted that one has a very short amp sustain, but the filter starts at about 80% or so and drops suddenly, and thats where my spikes are making who wave NON symmetrical about the zero line. So it's not dc. It's almost as if some sort of beat freqeuncy or phase thing happens to causes the wave to self oscillate and have really annoying non symetrical dips in it.
I have spoken with another engineer and he reckons he's seen this alot when recording live instruments, he reckons is just a product of the sound/wave itself.
This being the case, and the fact that to my ears the sound "sounds" perfect and the way I want it.
How do we post-correct this for the mixdown/master.. or is it perhaps not a problem at all and should just be ignored?
I'm waiting to hear from some mastering engineers on their thoughts.
John |
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| Eric J |
| Im right there with you, johno27. Its not like it's killing me or anything, its just annoying. Hopefully we can get to the bottom of it. |
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| Subtle |
| I dont know if this is the case here, but the JP has a bug causing problems when making filter sweeps. |
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| beats and beeps |
| the problem with the JP8080 is that it is not a jupiter-4. |
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| T-Soma |
Now that you guys bring it up I think I remember something similar with my Roland SH32. I don't own it any more so I can't verify though. I remember having a serious case when using a mic to record vocals that actually caused me a lot of grief.
Here is something I managed to find that should clear a few confused minds. DC Offset: The Case of the Missing Headroom |
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| johno27 |
Got some feedback from a mastering engineer on these issues.
He reckons the two main causes of this are:
A) A floating DC offset - Sub content between 1hz-10hz which often can't be removed with normal eq/filters unless it has a very steep slope. He uses a 96db/Oct highpass at 10hz to remove this sub.
B) Apparently it's quite common in synths/patches that produce more frequency/power below 500hz than above it. They reckon it is completely normal and not something to worry about for mastering.
I suspect B is where our problem lies.
Eric J, as another idea to test, have you tried taking the same patch that gives the offset problem and play it in a really high octave to ensure that it's avg content is well above 500hz ? and maybe apply the steepest highpass you have at around 28hz ?
If that suddenly makes the wave more symetrical and balanced then I think we can just ignore this problem. |
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| Eric J |
| quote: | Originally posted by johno27
Got some feedback from a mastering engineer on these issues.
He reckons the two main causes of this are:
A) A floating DC offset - Sub content between 1hz-10hz which often can't be removed with normal eq/filters unless it has a very steep slope. He uses a 96db/Oct highpass at 10hz to remove this sub.
B) Apparently it's quite common in synths/patches that produce more frequency/power below 500hz than above it. They reckon it is completely normal and not something to worry about for mastering.
I suspect B is where our problem lies.
Eric J, as another idea to test, have you tried taking the same patch that gives the offset problem and play it in a really high octave to ensure that it's avg content is well above 500hz ? and maybe apply the steepest highpass you have at around 28hz ?
If that suddenly makes the wave more symetrical and balanced then I think we can just ignore this problem. |
Let me try that, I can use the UAD Cambridge to apply an Eliptical 6 High Pass which has a hella steep slope. |
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