[sdiy] Pots vs Encoders, was Re: [sdiy] dave smith *instruments*

[Scott Gravenhorst]

Interesting thread for me because I'm in the thinking stage for a digital (FPGA)
synth design that I want to be "knobby".

I get the drawbacks and the advantages of both pots and encoders and I've been
wrestling with the question - pots or encoders?  Initially, I had wanted encoders and
a big LCD (well, kinda big, what I have is 128x256, but I may go QVGA).  I wanted to
surround the display with the encoders so that I could have multiple parameters
displayed at once.

This thread got me thinking - there's no reason why I couldn't have both pots AND
encoders.  They would all be assignable, but the pots could be used for those twisty
noodle things that are done during performance and the encoders would be mainly for
things that are set and then remain static during performance.

Of course the number of knobs is always an issue, but I do have to set a limit
somewhere.  I'm thinking 8 of each.

Since I would be using a PIC to handle the LCD anyway and it's over powered for doing
only that job, I could also use the PIC to read the encoders and it's 10 bit ADC to
read the pots.



Tom Wiltshire <tom at electricdruid.net> wrote:
>
>On 2 Feb 2010, at 13:06, cheater cheater wrote:
>
>> Tom,
>> are you saying people don't change the synth parameters during
>> performance anymore, because it's not the 70s?
>
>No, obviously not, that'd be silly. And I'm only silly after dark.  
>Mostly.
>
>I recognise that people want to tweak parameters and that you can't  
>do that using presets. You need to alter parameters, and that's the  
>function of a hardware interface. Designing a good hardware interface  
>is not an easy thing, and doing it for reasonable cost is even harder.
>
>I accept that a panel full of encoders and a single LCD screen isn't  
>much competition for pots, since the pot positions sometimes show you  
>something useful, and only the encoder whose value is on the LCD  
>tells you anything. But this isn't really comparing like with like,  
>although that is the situation on the P08 or Evolver, which is where  
>we came in.
>
>A better comparison would be something like the Solaris, which has  
>LCDs for each group of encoders, and consequently tells you exactly  
>what each value is for anything you can change. And furthermore, if  
>you change patch, it'll still be correct, which pots won't. Another  
>similar system is the Clavia Nord synths with their LED rings around  
>encoders. These provide instant visual feedback and update when you  
>change patch. Again, though, the resolution is limited - you  
>typically get 15 or 31 LEDs around the ring, which is 5-bit accuracy  
>at best. It's also worth remembering that having pots for each  
>function limits the number of parameters you can have. Most modern  
>synths have far more parameters than you could possibly put on a  
>control panel simultaneously. So you have to have some kind of multi- 
>function system, and this is the same situation as changing patches -  
>a pots position doesn't reflect the value.
>
>I think the ideal actually *is* fully motorised pots with one per  
>parameter. However, that is completely impractical (size & cost), so  
>we're left trying to find the best compromise solution. It isn't easy.
>
>T.
>
>PS: For what it's worth the interface for my monosynth has pots not  
>encoders. The encoder/LCD interface I'm working on is just a  
>convenience for testing things out.
>
>> That's what I was talking about.
>>
>> None of the situations I mentioned allows you to store presets:
>> - you can't perform on a synth using the parameters as a tool of
>> expression by just cycling presets
>> - you can't perform on a synth using the presets as a tool of quickly
>> accessing the sound you want, unless you're in a playlist band that
>> uses the exact same sounds over and over and never does anything
>> original on stage. Of course I'm not talking about this - if you just
>> want to use the same things over and over you're much better off using
>> a Kurzweil sampler, they're quite good at this. Miles Davis did not
>> have playlists for his songs and yet he was able to quickly recall all
>> the different sounds he made on his instrument.
>> - you can't directly use presets when mixing. They can only be an
>> entry point, but they will never work exactly the way you want with
>> the sounds you have, unless you're a 'loop musician' and are using the
>> same loops over and over. Every sound and every recording session are
>> different and require different compressor settings and reverb decays
>> and what ever else. Even when getting from an 'entry point' provided
>> by presets, to the exact sound you want, it's much easier to use pots.
>>
>> If the encoders don't show you anything ever, and pots don't show you
>> anything only after you've recalled a patch, then pots are not worse
>> than encoders. But all the above holds which makes pots better in my
>> opinion.
>>
>> D.
>>
>> On Tue, Feb 2, 2010 at 13:10, Tom Wiltshire <tom at electricdruid.net>  
>> wrote:
>>>
>>> On 2 Feb 2010, at 10:35, cheater cheater wrote:
>>>
>>>> I truly cannot come up with an idea of where in a musical studio
>>>> encoders are a good idea. Maybe alpha dials to move through menus
>>>> quickly. But for editing values?
>>>>
>>>> On a musical instrument you want to be able to change the sound to
>>>> what you have in your head quickly, and you get there by remembering
>>>> how the knobs were set up and how they were positioned.
>>>
>>> Encoders are a solution to the ancient problem of knob positions on a
>>> programmable instrument. You're completely right that people want  
>>> to change
>>> the sound quickly, and they mostly want to do that by patch  
>>> recall, not by
>>> setting the knobs up again - that was the 70s, man. And in the 70s  
>>> people
>>> responded by having a stack of keyboards set to different sounds  
>>> so that
>>> they *didn't* have to change all the knobs.
>>> As soon as you put programmability on a synth, it's easy to have a  
>>> situation
>>> where the knobs don't tell you anything. LCDs and encoders are one  
>>> attempt
>>> at a solution to that problem. I'm not saying they're perfect or  
>>> even the
>>> best solution, but I think it's worth remembering why they're  
>>> there and what
>>> they are good for.
>>>
>>> T.
>>>
>>>
>
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-- ScottG
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-- Scott Gravenhorst
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