24" IMac shared FW bus- Retarded

Discuss music production with Ableton Live.
dogma -
Posts: 33
Joined: Mon Mar 20, 2006 11:47 am

Post by dogma - » Wed Nov 08, 2006 9:44 am

I currently have a presonus fire box and any number of external FW 400 drives.
I am more looking at the future proofing ( an oxymoron I know when speaking of computers) because I want to get a glyph drive which have FW 400, 800, USB 2 and e sata ports at the back.
Also I'm looking to get a new interface when the PCIe cards start arriving.
I use a lot of samples and VST and AU's and almost never acoustic intruments, expect for my bass. The presonus has nice pre's but I dont really use them except for my bass and I also do some different sampling my tapping diffrent objects and then adding effects ect so latency is a big issue for me.
I spoke with the supervisors supervisor and they said I could cancel the Imac and get the MBP!!! Hell yeah. Its a rev a notebook which is a little worrying but I;ll spring for applecare I think

dogma -
Posts: 33
Joined: Mon Mar 20, 2006 11:47 am

Post by dogma - » Wed Nov 08, 2006 10:06 am

This may be of some interrest to some people - from the logic users forum:

Does it matter that the firwire 400 and 800 on the
> 24" imac are on the same bus? Some people have told
> me that may be a problem - don't know why exactly...

Two reasons:

1) If you use a FW800 device by itself, you get 800Mbps (100 MBps). If you combine FW400 and FW800 devices on the same bus, the FW800 device will operate at 400Mbps (50MBps), giving you a total maximum throughput of 100MBps, over the two devices.

AND...

2) The PCI bus to which both FW ports are attached has a maximum throughput of 133MBps. Even if the FW800 and FW400 ports operated at full-speed when devices are mixed (they don't...see point 1), you wouldn't be able to get full bandwidth anyway, since 100MBps (FW800) + 50MBps (FW400) = 150MBps, which exceeds the max bandwidth of the PCI bus.

Now, this limitation is a result of the underlying PCI architecture. The only way around this is to install a second FW bus, which is only possible on a MacPro or MacBook Pro, which have expansion slots.

Keep in mind that for 24-bit/44.1kHz audio, each track is:

(24 x 44100)/8 = 132.3 KBps = 0.1323 MBps

FW400, which can typically see real-world throughput of 30-35MBps (see www.barefeats.com), can deliver (at 30MBps, figuring conservatively):

30/0.1323 = 226 tracks.

Even moving to 88.1kHz would allow 113 tracks. And this is figuring at REAL WORLD throughput levels.

The point is this: unless you need VERY high throughput (and you might...keep in mind that a drum sampler like BFD can be streaming up to 30 tracks of 24/44.1 audio at once), two FW400 ports, each with up to 50MBps (which is the case with the 20" iMac), should be sufficient. FW800 should only be needed if you're doing very high throughput work (i.e. large, sample-intensive audio projects, real-time video encoding/decoding).

We're really getting to the point of diminishing returns for MOST people (although I recognize the need for FW800 or eSATA for some people). 100 MBps should be sufficient for most people.

For me, I plan to keep the computer for a couple of years and the Imac is totally closed as far as expansion is concerned.

Daisy chaining FW devices SHOULD be ok in theory, if all the pieces of gear work like they should but in the real world this isn't always the case and it also depends what type of recording you do. Its pretty hard to test new gear in a set up before you buy so its best to err on the side of caution. Trust me, I've had the pineapple inserted more than once with bad gear purchases over the years

mechcon
Posts: 234
Joined: Thu Oct 05, 2006 3:44 am
Location: Adelaide, Australia
Contact:

Post by mechcon » Wed Nov 08, 2006 10:55 am

dang, so your getting a macbook pro instead then? I was hoping to see from you how the 24" imac pans out, I feel that it will be a rarity in the communities :\

nevertheless, I did more research, and still got my eyes on it
MacBook Pro M3 Max, Scarlett 4i4 4th Gen, Ableton Move, LaunchPad Pro MK3, Behringer Edge, TecWav noise synth, Crank Sturgeon Plug Ugly contact mic, and oodles of effects pedals.

dogma -
Posts: 33
Joined: Mon Mar 20, 2006 11:47 am

Post by dogma - » Wed Nov 08, 2006 11:11 am

Yeah - the things about the 24", like the CD2 and FW 800 when I originally ordered it over two months ago have been negated by the new MBP CD2's.
Speedstepping worries me a little, but otherwise the MBP looks the go.
There seems no middle ground with apple. If they had an Imac with a conroe, heck the merom is a great chip so I guess thats not really a worry CPU wise but they noble the Imac with no expansion. There's not even a way to connect it to the next gen video devices (blu-ray and HDVD). And there selling movies as downloads? I guess there media iTV thing will do that so thats why they haven't added it to the 24".
To me, the MBP is the only flexible choice apart from a Mac Pro which is a little pricey for me.
So think about what you may need in two years. Damn beautiful screen though

Contra
Posts: 1263
Joined: Wed Nov 01, 2006 9:59 am
Location: Miami,FL. USA
Contact:

Post by Contra » Wed Nov 08, 2006 1:07 pm

John Sweet wrote:Ask for the supervisor's supervisor. They can do anything if you've just barely bought it.

Image


I am the fuckin supervisor.

pev
Posts: 93
Joined: Sat Jul 23, 2005 7:18 pm

Post by pev » Wed Nov 08, 2006 1:25 pm

Left Eye Dominant wrote:Is that the theory? Well strangely enough, I only seem to be able to get my Motu 828 MKII and FW HD drive to work without audio glitches if I chain the drive to the 828. If I run the 828 and HD drive on seperate FW ports I get snaps and pops all over the place even when just playing one stereo track (I am on a PC by the way). Works like a dream when chained.
Interestingly on my old G4 PowerMac MDD I used to have an 828/II and a Lacie big disk on two separate ports and it was fine. Now I've moved to an intel MacBook I have the drive daisy chained onto the 828. Seems OK so far but I haven't tried anything hardcore on it yet. If I remember I'll try doing an 8-track record to firewire disk whilst doing 8-track playback from disk when I get back later and report here...

~Pev

dazzer
Posts: 1240
Joined: Sun Feb 06, 2005 10:24 am

Post by dazzer » Wed Nov 08, 2006 3:14 pm

Maybe I'm misunderstanding the problem here. Is it that the iMac FW ports share the same bus? It's the same on my Powerbook and AFAIK the MBP too, 2 FW ports on 1 bus.

From what i read on the Interbutts, don't seem that PC users have much more luck with FW either, what with no bus power, dodgy chipsets, etc.

quandry
Posts: 1611
Joined: Tue Mar 18, 2003 2:31 am
Location: San Francisco
Contact:

Post by quandry » Wed Nov 08, 2006 3:56 pm

FORMAT wrote:
dogma - wrote:Daisy chaining FW devices for audio is a big no-no. In theory I suppose it would work but these things tend go wrong at the worst of times. In front of lots of people
I've chained a Motu Traveler, a HD and DVD burner on my only FW port, no problems!
yeah, not chaining fw devices is something I haven't heard of. I have three fw hds chained constantly, never a problem. I know two alesis multimix fw owners that chain the fw hd to their alesis, and for both the sequence (ie hd>alesis>computer of alesis>hd>computer) doesn't matter. I think people run into problems trying to power everything under the sun with their laptop--sure, I bet if you had four hds and a soundcard all fw daisy chained and all trying to power from the laptop the shit wouldn't work, but if you plug stuff into the wall and take the burden of powering stuff off of you laptop, it definitely can and does work.
Dell Studio XPS 8100 Windows 7 64-bit, 10 GB RAM. RME Multiface, Avalon U5 & M5, Distressor, Filter Factory, UC33e, BCR-2000, FCB1010, K-Station, Hr 824 & H120 sub, EZ Bus, V-Drums, DrumKat EZ, basses, guitars, pedals... http://www.ryan-hughes.net

quandry
Posts: 1611
Joined: Tue Mar 18, 2003 2:31 am
Location: San Francisco
Contact:

Post by quandry » Wed Nov 08, 2006 3:58 pm

dazzer wrote:From what i read on the Interbutts, don't seem that PC users have much more luck with FW either, what with no bus power, dodgy chipsets, etc.
geez, got to throw some mud at pcs here when everything in macland isn't perfect eh--nice. btw, some pc laptops have 6 pin firewire--do some research. and all pc desktops worth a salt have 6 pin and can power devices. ti fw chipsets are great, four years running here with no problems. blanket statements dissing one platform are just plain ignorant.
Dell Studio XPS 8100 Windows 7 64-bit, 10 GB RAM. RME Multiface, Avalon U5 & M5, Distressor, Filter Factory, UC33e, BCR-2000, FCB1010, K-Station, Hr 824 & H120 sub, EZ Bus, V-Drums, DrumKat EZ, basses, guitars, pedals... http://www.ryan-hughes.net

dazzer
Posts: 1240
Joined: Sun Feb 06, 2005 10:24 am

Post by dazzer » Wed Nov 08, 2006 4:14 pm

...

FORMAT
Posts: 1776
Joined: Thu Jan 10, 2002 12:13 pm
Contact:

Post by FORMAT » Thu Nov 09, 2006 8:05 am

mechcon wrote:hey FORMAT, in what order have you got them all connected? or it doesn't matter? and do you record to your external drive too from the audio interface?

FW out --> Motu --> DVD burner --> HD

Post Reply