Mac's built in digital I/O+AD/DA vs Audio Interface

[autodidactic]

I've just noticed that the majority of Macs these days come with spdif built in. This is purely out of curiosity but why do I never hear of people using the digital I/O of the computer? I realize that most people require more than 2 channels in either direction but I wonder why those of us that record alone don't take advantage of this feature. Is there any disadvantage of using a converter box and dedicated pre's with the built in sound as opposed to a firewire/USB/PCIxx audio interface?

[DrDeltaM]

If you only need 2 channels, it's very interesting, as it's a very low latency interface. Only drawback is 48kHz as maximum sample rate (no big deal to me). I'm using my G5's optical out to feed a Benchmark DAC-1, works great.

[autodidactic]

So the latency is good eh? (rubs his hands together greedily ) If it works well then I will have to think about the possibility of getting a two channel converter like the RME ADI-2 later on. I just ditched my i88x in favour of downsizing to an maudio firewire solo plus PTMP for compatibility. Otherwise I mainly use Logic. It would be nice to cut out an unnecessary interface when using Logic.

[max cooper]

Originally Posted by DrDeltaM

If you only need 2 channels, it's very interesting, as it's a very low latency interface. Only drawback is 48kHz as maximum sample rate (no big deal to me). I'm using my G5's optical out to feed a Benchmark DAC-1, works great.

Does this mean that the quick way to get iTunes into my nearfields is to go Toslink out of my G5 into the Toslink on my Rosetta 800?

And further, does it mean that I could get 2 channels at 48kHz in AND out of Cubase SX3 with just the Rosetta and the G5?

Is the S/PDIF carried on the Toslink?

Sorry for the ignorance; I've only really ever used ProTools, which is like only ever having used AOL and not knowing how to configure Email.

Why am I too lazy to climb under the desk and just try it?

[DrDeltaM]

The Rosetta800 doesn't have optical spdif I/O I believe, only supports ADAT on it's optical I/O.

[autodidactic]

Originally Posted by DrDeltaM

If you only need 2 channels, it's very interesting, as it's a very low latency interface. Only drawback is 48kHz as maximum sample rate (no big deal to me). I'm using my G5's optical out to feed a Benchmark DAC-1, works great.

Good News:

http://gemma.apple.com/documentation...ection_16.html

The 48khz limitation might be true for g5 owners but for powerbooks (and I'm assuming for the new mini's as well) the built in optical S/PDIF does up to 24 bit 96 khz

I'm liking the idea of a new dual core Mac Mini+RME ADI-2 more and more

[DrDeltaM]

Originally Posted by autodidactic

Good News:

http://gemma.apple.com/documentation...ection_16.html

The 48khz limitation might be true for g5 owners but for powerbooks (and I'm assuming for the new mini's as well) the built in optical S/PDIF does up to 24 bit 96 khz

I'm liking the idea of a new dual core Mac Mini+RME ADI-2 more and more

Sweet!

[tengu]

I trigger sounds in Logic/G5 from my MPC as well as using the MPC as a sequencer. I set Logic's to the digital outs of the G5 into my RME Fireface to bypass the firewire latency. I set the ADAT2 connection to send digital in to Bias peak. I only ever record two channels at once so it works great. I need as low latency as possible to be able to use my MPC with Logic effectively. I also send the RCA digital to the MPC for drum sounds so I can bypass the MPC's converters. The digital in/outs on the macs are genious.

[autodidactic]

Originally Posted by tengu

I trigger sounds in Logic/G5 from my MPC as well as using the MPC as a sequencer. I set Logic's to the digital outs of the G5 into my RME Fireface to bypass the firewire latency. I set the ADAT2 connection to send digital in to Bias peak. I only ever record two channels at once so it works great. I need as low latency as possible to be able to use my MPC with Logic effectively. I also send the RCA digital to the MPC for drum sounds so I can bypass the MPC's converters. The digital in/outs on the macs are genious.

Hmmmm....I wonder if you could do a latency shootout between the FF and the built in spdif at 2 channels each. I wonder which would win.

[TonyBelmont]

Originally Posted by autodidactic

Good News:

http://gemma.apple.com/documentation...ection_16.html

The 48khz limitation might be true for g5 owners but for powerbooks (and I'm assuming for the new mini's as well) the built in optical S/PDIF does up to 24 bit 96 khz

I'm liking the idea of a new dual core Mac Mini+RME ADI-2 more and more

I've been thinking the same thing, I'm going to probably pick one up.

[TonyBelmont]

Plus, I'm having thoughts of linking 2 x Mac mini's with the Logic Node software....

[jslevin]

The current series of Power Macs, with the dual-core G5 chips including the Quad model, supports up to 96K over S/PDIF, in and out. The previous models did not.

[AdamJay]

i use a DAC-1 with an iMac G5 (rev. B 1.8ghz) via spdif optical out.
24bit/96khz. its fantastic.

only thing is you dont get any software control for volume, as you do when using the onboard analog. you can mute it however. not a big deal as i've got it going through a Coleman M3 and thats my main volume knob.

the iMac is slowly becoming my "legacy" machine of sorts for PPC software.
with the MacBook Pro soon to be doing most of the heavy lifting. But it is handy having a digital link between both Macs.

Another bit of information that folks should know about .... the minijack optical out on the macs requires a minijack adapter for an optical cable.
RadioShack has discontinued these adapters, but you might still be able to find them on clearance at RS (like i did) for under $1. There are other sources to buy them from of course, but i grabbed a few of them because no one other than mail order has them now and they're so small and easy to lose. So, yea i'm a hoarder.

[max cooper]

Originally Posted by DrDeltaM

The Rosetta800 doesn't have optical spdif I/O I believe, only supports ADAT on it's optical I/O.

I'm determined; I figure this Toslink S/PDIF to AES/EBU converter is what I need.

http://www.altex.com/product_info.ph...oducts_id=2411

[autodidactic]

Originally Posted by TonyBelmont

Plus, I'm having thoughts of linking 2 x Mac mini's with the Logic Node software....

I was thinking of using a mini as my main machine at home but just using it as a node with my powerbook when on the road. If Apple could get the node thing to work with third party plugins, it would let the mini basically give as much extra muscle to my laptop as an expansion chassis would. Heehee Christmas is gonna be good this year. lol

PS...BTW I looked at the new imacs and they only have optical on the output, not on the input.

[DrDeltaM]

Originally Posted by autodidactic

Hmmmm....I wonder if you could do a latency shootout between the FF and the built in spdif at 2 channels each. I wonder which would win.

The build in optical will win. The Fireface adds 48samples of latency to everything (extra buffer for reliable Firewire communication).

[ToddS]

The optical I/O works great on my G5 dual 2.5. I use it for things like iTunes, games etc. I have tried recording with it using Garageband, and the latency was not that bad really, so maybe they are low latency, but I have never measured them.

[TEMAS]

These new mini macs have got loads of potential.

I haven't used the distributed audio features yet in Logic yet, but I must say I'm really tempted. Quick question: If it is only processing power that is distributed, I guess there's no need to load the node mini mac(s) full of RAM? Only the master Mac would need all the RAM and hard disk space?

Also, I understand that you can not distribute non-logic plugins or virtual instruments(or the exs24 - which is a bummer), but is it possible to distribute a track that uses no 3rd party plug-ins to a node, if it is being sent to a bus which uses a 3rd party plug-in? In other words, so long as I keep all my 3rd party plug-ins on bus channels can I still get away with distributing audio tracks which are routed to those busses?

[Phil Cibley]

.... the minijack optical out on the macs requires a minijack adapter for an optical cable.


Core Sound used to sell these, and still might. Sony portable minidisk units used
the same connector so a Sony accessories dealer might have them as well.

[T_R_S]

Originally Posted by max cooper

I'm determined; I figure this Toslink S/PDIF to AES/EBU converter is what I need.

http://www.altex.com/product_info.ph...oducts_id=2411

Hosa makes one too ...fifty bucks

[jslevin]

The build in optical will win. The Fireface adds 48samples of latency to everything (extra buffer for reliable Firewire communication).

I have to be skeptical of this. First of all, the Fireface manual says that its internal mixer/router adds 3 samples of latency ... we were just discussing this on another thread. Second, 48 samples of latency ain't squat anyway ... 1.1 ms at 44.1 kHz.

But mainly, there's no reason to expect better latency out of a stock built-in port than out of a FireWire device. Just because a port is physically on the chassis doesn't mean it isn't still part of a subsystem that has to interface with the motherboard and CPU in some fashion.

I would point out that Apple has little if any incentive to worry about latency when designing these built-in ports, as Joe User -- even Joe Power Mac User -- could really give a rat's ass about latency.

If you have some real technical source on this, I'd be very interested to see it. I'd also love to hear from anyone who's tried it in a real work situation.

[DrDeltaM]

Originally Posted by jslevin

I have to be skeptical of this. First of all, the Fireface manual says that its internal mixer/router adds 3 samples of latency ... we were just discussing this on another thread. Second, 48 samples of latency ain't squat anyway ... 1.1 ms at 44.1 kHz.

But mainly, there's no reason to expect better latency out of a stock built-in port than out of a FireWire device. Just because a port is physically on the chassis doesn't mean it isn't still part of a subsystem that has to interface with the motherboard and CPU in some fashion.

I would point out that Apple has little if any incentive to worry about latency when designing these built-in ports, as Joe User -- even Joe Power Mac User -- could really give a rat's ass about latency.

If you have some real technical source on this, I'd be very interested to see it. I'd also love to hear from anyone who's tried it in a real work situation.

My mistake, it's actually more then 48samples that the Fireface adds, as mentionned in the manual. See pages 80-81 "Safety buffer (64 samples on playback side only)" and "Core Audio's Safety Offset (32 samples)"

The last one seems general to CoreAudio, so the internal spdif port will have that too.

FWIW, you can run the Mac internal spdif port with a latency setting of 32 samples. Add 32 samples Core Audio Safety Offset to that, and you still have a lightning (pun intended) fast audio interface with optical spdif I/O.

The Fireface can also run at 32samples buffer latency setting, tho less reliable in my experience, so I run it at 64 samples now. Add to that the 64 samples Safety buffer and the 32 samples Safety Offset, and the 3 samples for TotalMix. It's still fast enough, but the Apple internal optical is faster.

[tengu]

Logic Audio integrates extremely well with the Macs built in Audio and allows you to run at lower buffer settings. This is advantages in itself.

Here are RME's pages concerning firewire latency

http://www.rme-audio.com/english/tec...s_tests_01.htm

My understanding is that everything would be coming off the same bus but firewire adds an additional 64 samples as the RME page states. This is a firewire safety buffer.

Don't expect any test results from me but when I set it up the difference was noticeable. I sometimes do midi latency tests and the like only to find my suspicions true. Not about to do any test this time but trust my fingers on the MPC and my ears. There was definitely an improvement with no sound degredation. It may have been the lower buffer settings using that using the built in digital audio allowed. It could have been a combination of both but there was a definite improvement. Without it there was a noticable latency, with the digital outs there was no noticable latency.

[jslevin]

Very interesting stuff ... thanks to both of you for taking the time to elaborate. 64 samples seems very manageable to me, but I certainly could see how you might want to take the issue to an extreme when working with an MPC.

[ptbarnum]

well, i thought this was a neat enough idea to track down a coax-optical converter (ramelectronics has all this stuff). it should arrive tomorrow, i'll hook up my minime to my macbook and give it a whirl

[Diskordia]

you think apple would get on the ball and make that optical output able handle more than 2 channels...with Frontline..they are trying to move them towards home theatre..that is an important step

i'm still running G4s though so maybe i'm missin something

[theblue1]

Originally Posted by max cooper

Sorry for the ignorance; I've only really ever used ProTools, which is like only ever having used AOL and not knowing how to configure Email.

[ELI-173]

This thread really helped me out.
I just ordered a G5 today. I already have a Lucid A/D with Genx Clock that has toslink optical spidf, and I just ordered a DAC-1 from Mercenary for the other side.

I didn't know about the option of using the optical ports, in fact, didn't see that it had any before ordering. THANKS AGAIN!

[sharky]

Originally Posted by ELI-173

This thread really helped me out.
I just ordered a G5 today. I already have a Lucid A/D with Genx Clock that has toslink optical spidf, and I just ordered a DAC-1 from Mercenary for the other side.

I didn't know about the option of using the optical ports, in fact, didn't see that it had any before ordering. THANKS AGAIN!

I second that. I didn't think of it either and got my G5 in a few weeks ago. It and my Lucid's have been getting along swimmingly and at lower latency than my old PC setup with an RME 9636.

It'll get me through till the verdict comes down on the Apogee Ensemble I'm eyeing.

Another example of how much of an insanely great resource this board is.

[ELI-173]

Hey guys,

I have a problem. I've been having no problem with using the DAC-1 with the optical out on the G5. It sounds great!

The problem is with the input. I'm feeding the optical in with a Lucid AD/96. When I go to the control panel and look at sound>input you can see that it's getting signal.

Now, in Logic 6 Pro (maybe the problem) I have it set to core audio and I'm getting no signal. Everything seems set up right, but Logic isn't seeing it.

Any ideas? Help!

Eli