[sdiy] MIDI volume to volts formula

[Tom Wiltshire]

> On 10 Jul 2018, at 10:35, Hugh Blemings <hugh at blemings.org> wrote:
> 
> Hi Brian, All,
> 
> On 10/7/18 16:34, rsdio at audiobanshee.com wrote:
>> It took a month before I got started on a MIDI Velocity histogram app, but only a couple of hours to actually write it (thanks to CoreMIDI, etc).
>> 
>> I’ve only done a quick test with an Ensoniq VFX set to the defaults, so I’ll need to spend more time with other keyboards as well as looking into the velocity curve settings options.
>> 
>> With the VFX, I’m only seeing 45 unique velocity levels (not counting 0, of course). The VFX reaches up to velocity 127, as well as 126, 125, 124, and 123, but then there are gaps between the remaining velocity values at 120 and below.
>> 
>> Based on your description, the DX7 only implemented 5-bit velocity instead of the full 7 bits.
> Two questions come to mind on this;
> 
> Would you be happy to share the app ?
> 
> If so, does it make sense to build an export function and then dump the resultant data into (say) a Google Spreadsheet so that we can build up an archive of the histograms ?
> 
> I realise that without actual velocity measurements from the keyboard itself or timings from the contact closures the data only really gives general resolution/bit depth info, but might be interesting anyways ?
> 
> Just a thought :)

Timings from contact closings is going to depend on the specific mechanics of a particular keyboard mechanism anyway, so might not be that general.

T.