Sound Canvas characteristics (with similar SC's)

[Alistair]

A recent topic reminds me of a question I'd really like answered.

Most of us know that the SC-55 sounds different to the SC-8850. It's warner, whereas the 8850 is clearer, more professional. (Same for other ED modules.)

However- what about 'similar' Sound Canvas modules? I.e. the SC-55 vs the SC-55 mkII, the SC-55 vs the SC-88, and the SC-55 vs the SC-88 VL?

I'm tempted to purchase a SC-55 MK II or SC-88 sometime, BUT I won't bother if their 18-bit sound is that of 'newer' Sound Canvases, i.e. my 885- makes them redundant. I guess what I'm looking for is that SC-55 sound in a module form, but more polyphony. Serial port is nice too..

- Alistair

[Cloudschatze]

SC-55 vs the SC-55 mkII

I'm going to use the CM-500 as a SC-55 reference.

The difference in sound between the two is negligible. While the mkII does have an 18-bit DAC, I have no way of telling if the recorded PCM samples are 18-bit. Furthermore, unless flat-response monitors are being used, it's unlikely that the difference would be noticeable if they were.

[shad0wfax]

The difference between 16-bit and 18-bit DACs is hardly noticeable. With 24-bit DACs the overall sound is clearer and crisper, but there isn't a big difference after all.

Regarding the PCM samples, I know of no synths which use samples better than 16 bit at 48 khz. I suspect that SC-55's samples are 12 bit, like Roland's D and U (including the CM-32P and the CM-64) series, or like Yamaha's TG series. 12-bit samples with a good synthesis engine and good DACs can sound very well.

[NewRisingSUn]

While the mkII does have an 18-bit DAC

If the mkII has an 18-bit DAC, what kind of DAC does the SC-55 have? My CM-500, whose GS part is supposedly identical to the SC-55, has a B&B PCM61P, which, according to the data sheet, is 18-bit.

[Cloudschatze]

While the mkII does have an 18-bit DAC

If the mkII has an 18-bit DAC, what kind of DAC does the SC-55 have? My CM-500, whose GS part is supposedly identical to the SC-55, has a B&B PCM61P, which, according to the data sheet, is 18-bit.

Hmm...
You're right, of course. There is quite a bit of bad information floating about the net. Looks like I'm helping add to it, heh. The SC-55 does have a 16-bit DAC though.

In light of this, someone else will have to make a comparison.  :wink:

This site suggests 18-bit samples on the mkII, as opposed to just an 18-bit DAC:

http://xv2020.s14.xrea.com

Interestingly, according to the website again, there were non-GM versions of the SC-55, CM-300 and CM-500.

[NewRisingSUn]

This site suggests 18-bit samples on the mkII, as opposed to just an 18-bit DAC:

I wonder what the point is of using an 18-Bit DAC when you only have 16-bit samples. And I thought at least the SC-88Pro had 44.1 kHz samples, not according to the page.

Interesting: according to the page, the SC-8850 has a bug that prevents the pitch of drum notes to be changed via NRPN.

[Cloudschatze]

This site suggests 18-bit samples on the mkII, as opposed to just an 18-bit DAC:

I wonder what the point is of using an 18-Bit DAC when you only have 16-bit samples. And I thought at least the SC-88Pro had 44.1 kHz samples, not according to the page.

There are enough question marks on the page to cause me to doubt much of it.

[Great Hierophant]

I know that my SCB-55 has a chip marked NEC uDP63200, and according to the datasheet I read it is a DAC with 18-bit output.  Unless the SCB uses two DAC chips, I would be accurate in concluding that the SCB-55 has a 18 bit DAC.  The photographs of the SCB-7, seem to show a NEC uPD6376, a known 16-bit DAC.  But that is an easy one to figure.  Many people with modules don't care to open them and of those that do, how can they tell which chip the DAC is?  

Also, is it possible that Roland would put an 18-bit DAC chip on a PCB but keep it in 16-bit mode as some allow.  That would effectively make the DAC 16-bit.  

I wonder what the point is of using an 18-Bit DAC when you only have 16-bit samples. And I thought at least the SC-88Pro had 44.1 kHz samples, not according to the page.

An excellent question. Is this truly much ado about nothing, at least until the 8820/50?  Perhaps this involves upsampling, which if not done well, can decrease the sound quality.  (Witness the controversy surrounding the SB Live and Audigy.)  

Some mkII based GS synthesizers have 16-bit DACs, others have 18-bit DACs.  I think that Roland may have gotten a good deal on the 18-bit DACs or otherwise the price differential between the 16-bit and the 18-bit DACs may have been negligible.

[Alistair]

I wonder what the point is of using an 18-Bit DAC when you only have 16-bit samples. And I thought at least the SC-88Pro had 44.1 kHz samples, not according to the page.

Interesting: according to the page, the SC-8850 has a bug that prevents the pitch of drum notes to be changed via NRPN.

Yes, curious. I'm pretty sure those newer SC samples are 44.1 KHz.

What I find curious is that the 'ST' models all have pros over some of their counterparts, but have inferior sound quality 16-bit DAC's!

And we've discussed that 8850 bug. THere's a fixer Sysex on the web somewhere.

This site suggests 18-bit samples on the mkII, as opposed to just an 18-bit DAC:

Thanks for the site, Eric. I really woudl like a MkII. But given what it says (assuming the SC-55 mk II and the 88 series sound te same as the SC-55, except better), I might prefer an 88/88VL!

- Alistair

[moturimi1]

@ Alistair

you mean there is a firmware update which corrects the bug of the SC-8850.
You can only download is from Roland Japan.

[Alistair]

Yeah, that's the one

- Alistair

[Great Hierophant]

Can there be so great a difference between 16-bit DAC and 18-bit DAC output?  Consider that if the samples are recorded in 16-bit, 16-bit DAC should be able to do justice to them.  An 18-bit DAC would only insert two zeros after the most significant bit.  Of course, if the samples were recorded in 18-bit, then there would be an improvement.  The hardware would not have to interpolate or degrade the sound quality.

[Alistair]

Therein lies the question, GH. I believe the mkII has a 18-bit DAC, but does it have 18 bit samples? And do the 88/88VL?

- Alistair

[Laust]

It's not completely without merit to use a higher resolution DAC than the input samples. Just listen to some Amiga modules on the original hardware (8-bit samples, 8- to 14-bit playback, with hardware mixing) and then on a PC with 16-bit (or even beyond) mixing/playback. The quality difference is quite obvious.

The SC isn't just playing back a fixed set of samples. It's changing their pitch and volume level, mixing them with other samples, and applying reverb/chorus. All these things can benefit from the greater resolution.

Of course, the Sound Canvases may very well use >16-bit internally, but even so...

[Great Hierophant]

This is a gross oversimplification, but the SC modules are constantly outputting a digital audio stream, and the more bits that DAC can convert at a time, the better the resulting sound will be.

[Laust]

Can you make up your mind?

[Cloudschatze]

Looking into this early GM and "non-GM" module tidbit, the only difference I've found between the two is that one will respond to a GM System On command, whereas the other will not, effectively keeping it in a permanent GS state.

NewRisingSun and I have been discussing this, and he pointed out possible differences in the GS version strings. A Data Request query sent to his GS CM-500 returned "GS Standard VER=1.10" for the version ID. I ran the same query on a GS/GM unit and had "GS Standard VER=1.20" returned.

Furthermore, an SC-55mkII returned the string "GS-28 VER=2.00 SC", and a PMA-5 returned "GS-28 VER=2.00 IW-GS".

What does it all mean? Well, who knows? - Roland does not have a GS-version revision/difference list (RolandUS anyway), leaving us in the dark regarding the changes. What it does show is that two synthesizers, exactly alike in outward appearance, may not be exactly the same. Likewise, two outwardly dissimilar synthesizers may share the same engine.

[Alistair]

Geez, that's helpful. ;P Thanks Roland.
Though, thanks for the info, Eric. How do you do a  data request anyway? (Assuming it's Sysex, can you provide it?) I'm curious to test my SC 55 now.

What's the difference between 'SC' and 'IW-GS' in terms of your last example, anyway?

I guess I'll have to grab an 'intermediate SC' (not as good as the Pro/ED, but better than the 55) and hope my engine is good.

- Alistair

[Cloudschatze]

Though, thanks for the info, Eric. How do you do a  data request anyway? (Assuming it's Sysex, can you provide it?) I'm curious to test my SC 55 now.

It is a SYSEX message, and though the SC MIDI implementation describes how to do this in detail, I found it to be much less cumbersome to simply use Ginosoft's GS Editor.
 

What's the difference between 'SC' and 'IW-GS' in terms of your last example, anyway?

I don't know, really. [humor]Though, given Japanese naming-conventions, and the PMA-5's portable nature, I imagine 'IW-GS' is short for 'Incorrigible Wanderlust - GS'.[/humor]

I guess I'll have to grab an 'intermediate SC' (not as good as the Pro/ED, but better than the 55) and hope my engine is good.

With the exception of the SCC-1, which could be found with either SC-55 or SC-55mkII engines, I think everything else was a bit more standardized. (Note: the Japanese, mkII-based SCC is known as the SCC-2.)

[Great Hierophant]

With the exception of the SCC-1, which could be found with either SC-55 or SC-55mkII engines, I think everything else was a bit more standardized. (Note: the Japanese, mkII-based SCC is known as the SCC-2.)

So, at least in Japan, there are three SCCs:  

The first, early variety SCC-1s use the SC-55 engine, with 317 patches, a 16-bit DAC and 24 voice polyphony.  

The second later variety SCC-1s use a hybrid engine, with 354 patches, a 16-bit DAC and 24 voice polyphony.  Generally found in the SCC-1B package, probably also in the SCC-1A package.  

The final, Japanese only SCC-2 use the SC-55mkII engine, with 354 patches, an 18-bit DAC and 28 voice polyphony.  In the US, the  equilavent is the SCD-15 (MPU-401/AT + SCB-55.)

By the way, are there PC-9800 versions of the SCCs like there is for the LAPC-I?