840av/ Nubus DSP Question

[beachycove]

Is it possible to add a DSP Nubus board to the 840av, so as to create a multi-dsp-processor machine for sound editing?

I do know for a fact that you can add a DSP board or even three of them and use all installed dsp chips for certain Photoshop filters, which thus run very snappily indeed on such an 840av. I also have read that multiprocessing capacity (much better than the usual in the old MacOS) is built into the "mini-OS" that runs the DSP chips in the AV Macs (yes, an OS of a sort within MacOS). Does anyone happen to know if you can do the same with a DSP Nubus board and dsp-aware sound software like Soundedit 16?

If so, any suggestions as to what I'd need to look for? What would presumably be ideal is a card with an identical DSP chip or chips to the one already on the logic board.

 

[TylerEss]

I'm not sure that SoundEdit 16 is an ARTA program... the only DSP-aware sound app that I know of for sure is (old versions of) Deck.

You can do what you want, but only with certain DSP cards... the common ones like PhotoEngine and Thunder {II,IV} GX use their own software instead of ARTA.

I guess the NuMedia and Spectral Innovations NuBus DSP boards support ARTA, so with those you'd be able to do what you want. Also, they'll give you luvvin' with the AV DSP Power photoshop plug-in.

 

[Bunsen]

I seem to recall that Deck II is ARTA aware. It certainly is Nubus Digidesign Audiomedia II and 840AV DSP aware. If you want cheap, known good audio DSP speedup on a Nubus machine, I'd go the Audiomedia II. It only has one DSP onboard (56Mhz) but it's a sound card rather than a repurposed video accelerator.

The AMII also has S/PDIF digital coax stereo and 18 bit analogue stereo i/o. The AM 1 doesn't have S/PDIF.

 

[Bunsen]

Or you could set yourself up with an old version of Protools and a couple of these or similar.

 

[beachycove]

ARTA, yes that's it, I couldn't remember the name.

On Soundedit 16, this from James Wang's old MacAV FAQ:

SoundEdit Pro must be updated to version 1.0.5 to recognize the 16-bit audio capabilities of a 660av or 840av. Macromedia has since released the more capable SoundEdit 16.

I take it that means that "the more capable Soundedit 16" is ARTA-compatible.

 

[Bunsen]

Deck II is multi-track though. The faster the Mac and hard drives, the more tracks you can mix in parallel. Someone here (paging?) got 24 tracks out of an 8100/G3

 

[Unknown_K]

I would think you can. I have used photoshop 3 on my IIfx and the DSP control panel showed both the set of DSPs on my Thunder/24 with GX addon and a seperate Nubus DSP card in use at the same time.

 

[TylerEss]

I take it that means that "the more capable Soundedit 16" is ARTA-compatible.

Not in my experience using SoundEdit 16; i think that statement is more talking about the fact that SoundEdit Pro was less fancy in other ways... but I may be wrong.

Someone here (paging?) got 24 tracks out of an 8100/G3

That'd be me! I got about a dozen realtime effects out of it, too. It took *lots* of config-tweaking to get it there, but it sure did it! It actually could do more like 28-30 tracks, but at those levels it would occasionally hiccup and skip. 24 tracks was steady enough I felt OK about giving it to my father-in-law and forgetting about it.
Up to 16 tracks was really fun... I set the 10,000RPM drive's mode pages to statically segment the cache into 16 segments, and then set Deck's cache to 1/32 the disk cache, so each cache segment was twice the Deck cache size. With such a small cache, there was almost no lag-time between pressing 'play' and getting playback, but the playback was still smooth and reliable because the hard drive firmware's read-ahead kept the buffers full quite efficiently. I was really banging on the access time of the disk, which was great because a fast drive, even on a JackHammer, still doesn't have that great of a sustained data rate (9-14MB/s). While working on this method, I discovered a bug in Deck II that causes it to loop audio and crash if you set it's cache size too low (like, way way below the default, which they encourage you to _raise_ for increased track counts)

Once I moved beyond 16 tracks (the limit of the drive's cache segmentation) this method quit working and I had to go back to the standard method of "use a big buffer in Deck" which works, but results in much-increased latency on the play-button. For example, if you have a 256k buffer, a file with 24 tracks will have to grab 6MB from disk before it can even begin playing: this translates into a 1-2 second latency. This kind of configuration does *not* make the old 8100 shine, because it stresses raw transfer speed much more than access time.

I suspect that with a modern 15,000RPM drive that has a 32MB buffer that can be segmented into 32 or more segments, 32 usable tracks in Deck II on the 8100/G3 would be a reality, using the "tiny RAM buffer and let the disk do all the read-ahead optimizations" strategy. I mean, SCSI works a lot faster when everything you ever ask for is already in the drive's cache memory...

the DSP control panel showed both the set of DSPs on my Thunder/24 with GX addon and a seperate Nubus DSP card

Were you using the Thunder/24 GX and a ThunderStorm board together? I think that configuration is supported, because they're both SuperMac DSP Photoshop cards... Were the 4 DSPs (two on the GX, two on the ThunderStorm) substantially faster than 2?
I think a Thunder IV GX and a PhotoEngine together can load-balance, too, but I'm not *sure*. I can't say that I'd mind using Photoshop on an overclocked IIfx with a fast SCSI subsystem, 8 DSPs, and that NewerTech ramdisk NuBus card for a scratch disk. }

Are you using upgraded GWorld memory on that Thunder/24? If so, does it make scrolling in Photoshop as much faster as I think it should? I've always been really excited to get a Thunder/24 + GX or a RasterOps Horizon24 setup to try out Photoshop on GWorld memory...

 

[beachycove]

I may need to check out other software if I have the details wrong. Never tried Deck II but will take a peek.

The info on Nubus cards is also helpful. I do not have a sound card at present, but will keep my eyes open now that i know what to look for.

 

[Unknown_K]

I was using the STORM technologies DSP card I believe (has the same exact DSPs that are on the Thunder/24 with GX addon. I could have put a couple more DSP cards in but my IIfx was full of other cards. Never timed the difference between 2 and 4 DSPs.

Scrolling does seem faster with the GWorld ram on the Thunder/24 and photoshop 3. I was looking for ages to find Gworld RAM and ended up snagging some on a set of 3 AVID enhanced Targa 2000 Nubus cards (called the ABVB AVid card). The Targa has 4MB of VRAM and 4x4MB of 68pin Gworld SIMMs onboard. The Thunder/24 only seems to work with 2 of the SIMMs installed for 8MB max Gworld ram.

 

[TylerEss]

yeah, the SuperMac ThunderSTORM board is the same as the Storm Technologies board, 'cuz SuperMac bought STORM technology to get the DSP technology. That's awesome to load-balance across the cards.

Congrats on finding GWorld SIMMs for your Thunder/24; I think they usually get used just as a cheaper Thunder IV, so I'm really happy to hear that you're taking advantage of it.

 

[Unknown_K]

I hate looking at empty sockets, and it took me a few years to figure out what SIMMs go in them (never seen any for sale anywhere).

 

[Bunsen]

If you still want to give it a go, this card has the same brand of DSPs on it as the 840AV. I have no idea if this helps or not.