G2 16 -> 24bit memory upgrade possibilities?

[DSPaudio]

Any ideas if the 16bit memory in the G2 could be upgraded to 24bit with a working result? I'm not familiar with hardware memory architecture but it seems like truncation is going on and if that truncation was occurring within the memory itself then we could just install proper 24bit memory no?


This and a DIY or aftermarket ADAT I/O board would really make my day.

Cheers

[Antimon]

Sounds fantastic enough to be true!

/Stefan

[dorremifasol]

Even if you could make that modification, probably all the G2 code is designed to work with 16 bit memory, so in the end you will not achieve any difference at all.

But you can sue Clavia for advertising a device with 24 bit memory (in all the places where it's mentioned), and selling it with 16 bit memory instead.

[drapdap]

[ark]

Aren't we getting just a little ahead of ourselves here? What exactly does it mean to say that "it seems like truncation is going on?" Can someone post a G2 patch that shows this truncation happening?

If not, I don't understand what the problem is that the original poster is claiming.

[Antimon]

I think it's been established that the delay modules on the G2 work with 16-bit audio, while the rest is 24 bit. So if you pipe an oscillator into a delay, the output from the delay will be 16 bit resolution.

Is there such a thing as 24 bit memory?

/Stefan

[ark]

[jksuperstar]

The external bus of the 56k series is indeed 24 bits wide. And it is possible that truncation is happening in hardware, not software. But it would be a series pain in the ass to wire up 24 data + address bits for 4-8 DSP processors.

[ark]

[DSPaudio]

[varice]

For memory external to the DSP the G2 system uses a SRAM SMD IC (one per DSP) organized as 262,144 words x 16 bits (I've seen an Alliance AS7C34098-12TC part used). That memory chip (and the main and expansion board layout) only has 16 I/O data lines connected to the DSP data buss. That number of words divided by the G2 96KHz sample rate gives you about 2.73 seconds of data storage, which matches the 2.7 second max time of the delay modules.

So,the main and expansion board layout for the this 16 bit SMD IC make a 24 bit DIY "drop in" replacement not possible. The DSP code also is almost certainly written to do bit reduction for the memory writes and to fill the unused 8 bits of the 24 bit DSP register on memory reads, I would think.

The DSP code could have been written to use 24 bit data with that 16 bit chip, but it would at least double the read/write time (two R/W cycles instead of one per sample, maybe a show stopper?) and require a more complicated memory pointer scheme. And of course, that also would reduce your sample storage time by 1/3 down to about a max of 1.8 seconds. Many digital delay devices have options to reduce bit resolution and/or sample rate if longer delay times are desired. Too bad the G2 delays do not have these kind of options and Clavia failed to mention that the delays were only 16 bit.

Availability and price may have driven the decision to use 16 bit versus 24 bit memory. There is a larger supply and selection of 16 bit parts. I have not compared prices, but I would think that the 24 bit chips are a bit more expensive.

[dorremifasol]

The use of 16 bit memory is understandable for a number of reasons.

The false advertising is not.

[3phase]

[varice]