Retuning POKEY for better range

[Synthpopalooza]

So, one of my compatriots in the 7800 forum came up with this:

 

 

It's a series of retuned POKEY note tables, in 16 an 8 bit, 64 and 15 khz clocks.  The theory is, by changing the base tuning from A4=440 to something else, you can extend note accuracy into the 7th octave.  This is an ideal workaround if you are doing music exclusively in $Ax distortion. 

 

I played around with this, and I like the ideas.  I wonder if this would work in other settings, i.e. $Cx bass plus $Ax leads, or 15 khz $Ax bass plus 1.79 mhz $2x lead.

[ivop]

Good to see just tuning is explored! I once suggested something similar in one of emkay's threads. Depending on the key of your song, it could be beneficial to use a different AUDF table. It might even sound more in tune than the original, which was played on well tempered instruments

 

One can vary the A=440Hz variable up and down, and can either tune just or well tempered. Lots of tunings to explore! Maybe I should pick a random .rmt file, determine its key, and reassemble with different frequency tables. Then find the best A to base your just tuning on. Perhaps this could even be automated.

 

Regarding $Cx bass, there is a lot less leeway. But it could be determined which keys are mostly in tune having $Cx bass, and try to match your $Ax table as close as possible. Then create your song in one of those keys Songs that are in a key that's problematic could be transposed to the closest key.

 

[emkay]

3 hours ago, ivop said:

Good to see just tuning is explored! I once suggested something similar in one of emkay's threads. Depending on the key of your song, it could be beneficial to use a different AUDF table. It might even sound more in tune than the original, which was played on well tempered instruments

 

One can vary the A=440Hz variable up and down, and can either tune just or well tempered. Lots of tunings to explore! Maybe I should pick a random .rmt file, determine its key, and reassemble with different frequency tables. Then find the best A to base your just tuning on. Perhaps this could even be automated.

 

Regarding $Cx bass, there is a lot less leeway. But it could be determined which keys are mostly in tune having $Cx bass, and try to match your $Ax table as close as possible. Then create your song in one of those keys Songs that are in a key that's problematic could be transposed to the closest key.

 

 

For a lot cases, the 16 Bit resolution of POKEY is the "last saving point for music" . 

But, if a tune has to be clean from the start to the end, the full control of Pulse Width Modulations is strongly recommended. 

In theory it offers an 8 bit plus 8 bit resolution  and it multiplies with the available offsets that were also about 8 bit plus 8 bit possibilities. If you do the math, it's about a (almost)  "32 Bit" resolution. This can vary between full 16 bit sound and added waveforms with approximated "real notes" . 

 

It also offers some "magic"

 

 

 

 

 

Edited September 9, 2020 by emkay