rotary encoders mb64e

[kris]

forgive me for asking a dumb question maybe

im buliding a mb64e with the layout in the pic below

as you can see ive got 16 rows of 2 pots

im thinking of replacing these with rotary encoders maybe even encoders with      push-buttons

my question as ive never used rotary encoders before is what would the advantages

be over analogue pots

thanks kris

P1010044.JPG

[lylehaze]

Encoders are digital devices, Pots are analog. So connecting them is different.

More importantly, Pots are absolute devices, i.e. the if you turn it full left, it stays

full left until you move it again. Encoders give off signals like "I'm being turned right" or

"I'm being turned left". But they have no stops or limits to their motion.

Consider an encoder with a LED Ring (to show it's position). You turn the knob, and the

LED ring shows you the "current position". If some outside message (like a MIDI CC#7)

wants to control the same knob, the LED ring could show the changes, without needing

to resort to a motorized pot. If you want the Pot position to change, you'll need to

motorize it.

So, in this example, it's easier to combine local (the knob) and remote (the MIDI volume

command) with an encoder and LED ring, than it would be to buy, build, and operate

a motorized pot or slider.

Encoders usually ahve a longer usable life, too, as pots tend to get dirty and "scratchy",

but that might just be my opinion.

LyleHaze

[kris]

thanks for the reply

i wasnt thinking of using led rings

so i dont know if there would be any advantage for me

well let me put it like this to use rotary encoders ive got to order some plus dinx4

board (ive already got pots)

but not having used encoders before its difficult i might find ways of using them which would be very handy

  ??? ??? ???

kris

[lylehaze]

I guess the short answer is..

Encoders can ALWAYS be turned up or down.

Pots only turn until they reach the end of travel.

Because my mixer can be driven with a local encoder,

OR a remote console, OR by a sequencer, the use of

encoders is pretty much required.

Hope it helped.

LyleHaze

[kris]

yea thanks

its good to get the  input of someone whos using them

kris

[MRE]

Kris:

You do not need LED rings to use encoders. That was only one example (of visual feedback).

Think of an encoder as a 'never ending pot' It will continue to spin. There are many advantages to encoders, and a few advantages to pots.

as Lyle pointed out, an encoder can be dynamically altered by software without physically moving the dial. Let me make an example:

Lets say you have a sequencer with a knob for note selection.

As a pot the knob would act as follows:

Pots are absolute, so

1: a predefined maximum limit on the number of notes it can represent. This is based on the physical properties of the pot, and the Analog to Digital converter attached between the pot and the micro-processor. For example, an ADC may only have a resolution of 256 steps. Thus 256 notes. Which, may be just fine for musical notes. EXCEPT: a) as pots degrade over time, they become harder to 'lock onto' the note you want. b) 256 steps on a one inch arc sweep might actually be a bit too fine for 'realistic' use. The truth about most analog game controllers is that while the knob may produce 256 steps of resolution (or 512), the game software cuts this down to two or three!!!!

2: When power is removed, the pot 'stays put' so it is preset to a certain value when power is re-applied. This can either be an advantage or disadvantage depending on how you work. Just remember that it will be preset and sending out note data at that position value untill you drop it back to zero. Is this knob a volume control? a note control? a filter setting?

Every time you work with a song, you need to remember where everything goes.

(there are many ways around the limitations of pots for use in a sequencer, but that is a different discussion. Pots can be made to continuously rotate, and on power-up the processor must 'remember' what pot value represents zero.  For the sake of discussion this. [and for anyone who says: Thats not entirely true MRE ;) ] )

Encoders will behave as follows:

They are relative, so they are directly opposite to pots!  ;)    an encoder's resolution is only limited by software (and thus under your full control via MIOS/host software!  Yippiee!!). Each pulse is representative of one note (in our example). So, how far can your micro-processor count? How much knob turning do you want to do? There is no real limit here. Also, detented encoders give a nice solid click to let you know the note has changed, while non-detented give a smooth operation for volume or filter sweeps.

Finally, encoders have no 'memory.' When power is re-applied, they are affectively at zero (unless your software remembers the setting.) This is actally very nice. For example: Loading a new song into your editor has a filter setting at 20 percent at the beginning of the track... then that associated knob is at 20 percent.

For this reason, you will often see encoder knobs without a marker or pointer. It is all relative, and changes regularly.

If you want to bump something up or down, you just turn the knob a little up or down. You dont have to ask "how much further can the knob go?"

In most cases, encoders are best.

However, immediately to mind Volume controls generally are better served by pots or sliders. Volume is absolute, with a diffinitive start and stop, and you almost always want it to represent 'true' setting, not relative.

Case in point:

It should not matter what the volume setting was saved into the song. When I power up for the first time with the slider all the way down, I dont want to hear anything comming out.  Not a mistake my speakers can handle!  ;)

[MRE]

ultimately the choice is yours,

some general guides:

Pots are great for mixing sectios for volume, high, mid, low, cutoff, cross fade, headphone send, etc. These are things that dont change much, and often you want them to 'stay put' between power cycles/gigs/mixing sessons.

Encoders are generally better for instruments, sequencers, performance gear. Etc. From song to song, much of their duty is relative.

Again, some values you want to 'stay put' though, like the final output volume control of an instrument.

It looks to me like you are building a mixing console, and thus most of those pots can stay right where they are. If you plan on using some special effects plugins, you might want to change THOSE knobs to encoders.

[kris]

thanks very much MRE

 

  thats exactcly the imformation i was looking for

  the layout im making is for using cubase with reason rewired

  so i can add a few drum beats basslines etc with live musicians

  this time its going to be mios which is new for me

  id like to use encoders as ive never used them before but wonderd if they would   

be worth the extra exspense

    it looks like a mixer layout the rotarys are used to alter filters,pitch etc in reason and control vsts and effects in cubase

  why i thought about encoders is if i got the ones that push in and  out as well then each rotary could control two effects etc  ie pushed in turn one effect pulled out turn the second effect so doubling the amount of parmeters i could control

from the same panel space (please correct me if im wrong)

i think i might just have to go for encoders for the experimentation

  thanks a lot for the input

  kris

[MRE]

most push encoders only offer a clicky button to the encoder. The ones that operate as two seperate encoders (or as a toggled encoder) as you are thinking of are pretty damn expensive and hard to find (hope someone corrects me and has a good source for them).

So, push button encoders offer a button built into them. If you keep track of the button events then yes you could control two parameters. But it wont be push/pull.  More like, Push, turn, push again, turn.

You would have to ask someone who uses them that way, but I see them working better for enable, disable type events like muting, or filter on/off.