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Subject: Re: [korgpolyex] Bugs

From: Alex Drinkwater <the_voder@...>
Date: 2008-11-12


On 12 Nov 2008, at 14:00, Michael Hawkins wrote:

This email is much longer than it should be but anyway...

The Original Poly-800 Bug
The main reason that the nasty sequencer bug is fixed in the HAWK-800 is because the original Poly-800 had a shocking MIDI implementation and also a known bug. And the HAWK-800 code is based on the EX-800 code which doesn't have the sequencer bug. Then all of the HAWK-800 features have been added into that EX-800 code. That new code includes buffering of certain MIDI commands so that there is much less chance of MIDI data causing the HAWK-800 any problems. In the next minor firmware release, I will be including the stack overflow protection that I had previously talked about. The stack protection will cause the HAWK-800 to restart if the MIDI buffers overflow. This will put a complete stop to the Poly losing patches if it gets swamped by MIDI messages.
I do not think the Poly 800 MK2 suffered from the original MK1 bug at all. If patch 66 caused a crash of a MK2 Poly, I would think it was because of out of bounds data in the patch. The MK2 is more sensitive to out of bounds data in patches because of the effects parameters.

303 Accents and the Poly Sequencer
First of all, I am not that familiar with the 303 at all (I certainly know the sounds but never used or ever touched one myself). But I know the Poly sequencer is shockingly inadequate as it is now. The right way to improve it would be to replace it entirely with a completely rewritten software sequencer module. That is something I would LIKE to do but it is not in my plans to do so as yet. Having said that, there are a couple of short term improvements to be made.

OK, I have an idea:
If Mike can add NRPNs for all sound parameters, I can have a mess around and try and work out which parameters could be altered to make those accent sounds. The current MIDI controller setup is great for live sound tweaking, where you're only editing one parameter at a time, but is less easy to use when controlling parameters from a sequencer, so I'm still holding out for those NRPNs at the moment. Once that is in place, I can try some different controller tweaks, and see what works best, and post some examples here, and we can decide if it's worth pursuing some kind of accent feature, whether under local sequencer control, or as another play mode.

i) I plan to implement an arpeggiator with features somewhat similar to a cut down version of the Kawai K5000 arp. Obviously how much "cut down" depends upon time and my inclination to do it which depends upon musician input and how much pizza and beer is provided. :-)

I've never really been into arpeggiators, personally, but I know many people are. I can see it's a more obvious 'performance feature', mind you.

ii) Route the sequencer to VCF cutoff, resonance or EG1/2/3 attack (with the sequencer notes either playing or not).

That would be cool, but would it actually be possible to have the sequencer control ANY sound parameter? I actually think it would then make the sequencer a really inspiring tool for loop-making, rather than the rather sad afterthought it currently is.
If it only going to be able to control a selection of parameters, I'm not sure I'd list env attack as one of them. Off the top of my head, these are the parameters I'd want to be able to control:
Filter cutoff
Filter resonance
Filter env. decay
Filter env. attack (maybe)
One of more of the LFOs (rate, mod amount)
DCO1/2 Octave
DCO1/2 hormonics
Slide (I'd still want to be able to do this, whether it meant being able to overlap notes, or needed a special slide flag to be set for that step)

iii) Provide multiple sequencer patterns that can then be sequenced in a user set order.

I was thinking of this too. Maybe patterns could be switched from the keyboard.

Now the big issue here, is that the ARP will take a lot of work and I have it as the highest priority of things to do. But the question should be directed to HAWK-800 owners as to what they would rather see first. ARP or better sequencer? Since I think using a Poly as a sequencer is just plain silly ( :-) ), that is why I chose to work on the ARP first. I do know that I would like to have points ii and iii though because they would make a really bad sequencer - well - a little less bad.

Of course, it drove me nuts to discover just how bad the sequencer was when I bought my first Poly back in 1984. And the same "drive me nuts" problem is that you cannot hold a note or notes over while dropping others. The ability to hold notes and not others is such a fundamental feature of a polyphonic sequencer. However, I respect the Korg engineers that built the Poly because they were working to build a budget synth and they simply ran out of space to fit features into the one 8K ROM. The annoying bit is that I would have to rewrite the entire sequencer in order to fix just that one thing so I don't see this being addressed until I one day get to rewrite the whole sequencer from scratch.

Anyway, the bottom line is ARP or sequencer features - which to do first?

From my point of view:
well, it's dodging the question, but I'd like NRPNs before either. If I'm going to use it with a sequencer, then I can use my sequencer's arpeggiator, and if I'm going to be driving it from a sequencer, I'd like also to be able to change all the synth parameters with their own dedicated controllers. Don't get me wrong though; I think both the arpeggiator and the updated sequencer would be cool. I'd say, if I can have my slidey/accenty 303-style sequencer (or something that allows me to do something similar by altering certain parameters per-step, and having slides between certain steps), then I'd go for the sequencer as a priority. Otherwise, I'd plump for the arpeggiator, because you're obviously more excited about working on it, and I think more Hawk-800 users out there would want that, to be honest.


a|x




Mike


From: Alx <the_voder@...>
To: korgpolyex@yahoogroups.com
Sent: Tuesday, November 11, 2008 4:54:23 AM
Subject: [korgpolyex] Re: Bug

--- In korgpolyex@yahoogro ups.com, Russ <russdaren@. ..> wrote:
>
> I found out earlier this year (and had it confirmed by others on this board) that sending too 
much midi data can crash a poly 800. Like sending 1 minute's worth of note/pitchwheel in 1 
second.It would wipe out your patches!
> possibly similar?
>

It's a well-known issue with both the Poly-800 and EX-800. Very annoying. It's a major 
reason I was excited about the Hawk-800 mod, in fact. I was never able to use either my P-
800 or EX-800 under sequencer control, because it would periodically crash. Not only that, 
when it did crash, it would overwrite parts of the memory with random data, so I'd end up 
losing all my patches. Happily, after installing the mod, it seems perfectly stable, AND I can 
now tweak parameters from my XStation controller while it plays, which is a bit of a 
revelation!

a|x