usb vs firewire?

[davesec]

i searched to see if i could find a similar thread. i know firewire is faster & usb is more capatible, but is one way way better than the other as far as recording goes? or does it all depend on the converters etc

thanks!

[Jeff White]

Firewire, always. I don't know the specifics, but I have seen it come up a whole lot on the net in discussions and firewire always wins out. I think because of drivers and actual real-world bandwidth.

Jeff

[chris harris]

I guess you're talking about interfaces?? I haven't seen many usb interfaces.

If you're talking about harddrives...
I've been using USB 2.0 drives for years. And, I have no problem playing back projects with 24+ tracks.

[Phiz]

Be wary of any USB interface that is powered by the USB connection. The USB specs do not allow for much power. Some phantom powered microphones will draw more power than the USB connection can provide and this results in degraded performance. A USB interface with an additional power source should not suffer from this limitation.

There are two different phantom power specs 2mA and 10mA (DIN vs IEC) from a +/-48 volt set of rails. P=IV=0.010*(48*2)=960mW

The USB spec is 5mA from a single 5 volt rail. P=IV=0.005*5=25mW

I can't find the Firewire spec, but I know it can provide several watts.

[Andy Peters]

Be wary of any USB interface that is powered by the USB connection. The USB specs do not allow for much power. Some phantom powered microphones will draw more power than the USB connection can provide and this results in degraded performance.

There are two different phantom power specs 2mA and 10mA (DIN vs IEC) from a +/-48 volt set of rails. P=IV=0.010*(48*2)=960mW

The USB spec is 5mA from a single 5 volt rail. P=IV=0.005*5=25mW

Not correct.

Phantom power is, by specification (48 V through paralleled 6.81k resistors), limited to 14 mA per microphone, and in practice you won't see more than 10 mA used per mic, as you only get 14 mA when you short pins 2 and 3 of the XLR to ground (pin 1).

Now, the USB spec allows for 500 mA -- NOT 5 mA! -- at 5 V; included in the spec is a descriptor that the device uses to tell the computer how much current is required. So to get 10 mA at 48 V your step-up converter needs at least 100 mA from a 5 V supply, which is fine for a bus-powered "High Power" device. 400 mA is plenty to power most audio devices. I can think of a bunch of USB audio devices which quite happily power two phantom-powered microphones with no problems.

Note that bus-powered HUBS can't supply more than 100 mA to their downstream port, so if you plug in a device that requires more current, the computer will pop up a dialog indicating that there's not enough power available and it will not start the device. The solution is to use a self-powered hub (one that uses a wall-wart for power).

Hope this clears things up.

-a

[ballpein]

I think the common wisdom is to stick to firewire. Having said that, I've used both (for drives and interfaces) without major issues - but, all things being equal, I'd chose firewire, if for no other reason than I always seem to be running out of USB ports, while FW can be daisy-chained. Both have their glitches and both can be hinky from time to time, but both should do the job.

[Shaka]

Technically USB 2.0 is faster than firewire 400. However, this is not the whole story.

Firewire has the ability to full duplex. This means that the drive can send and receive info at the same time. USB and USB 2.0 do not have this ability and are either sending or receiving at a given time but not both.

The ability to full duplex is why firewire is better than USB or USB 2,0

[Jeff White]

Technically USB 2.0 is faster than firewire 400. However, this is not the whole story.

Firewire has the ability to full duplex. This means that the drive can send and receive info at the same time. USB and USB 2.0 do not have this ability and are either sending or receiving at a given time but not both.

The ability to full duplex is why firewire is better than USB or USB 2,0

Well, as far as I am concerned, there you have it.

1) When you are using an interface to record, you are also using that interface to play back. You need to send/receive simultaneously.

2) When you are using a drive to record, you are also using that drive to play back. You need to send/receive simultaneously.

So I guess full duplex it is.

[Cyan421]

about the full duplex thing

Motu's 828mk2 is available in USB and is supposed to latency free monitoring (i.e. in audio doesn't go to the cpu and back it gets routed straight out the box, yes some AD converision latency). So light of this I don't think Firewire is an all out winner, unless im wrong about that.

[chris harris]

Well, as far as I am concerned, there you have it.

1) When you are using an interface to record, you are also using that interface to play back. You need to send/receive simultaneously.

I've used a USB interface to playback and record simultaneously.

2) When you are using a drive to record, you are also using that drive to play back. You need to send/receive simultaneously.

I've used a USB drive to playback and record simultaneously.

there's obviously some misunderstanding about this "full duplex" business. I've used a USB 2.0 drive to playback 16+ tracks while simultaneously recording 12+ tracks. And, the hard drive didn't even break a sweat.

[Ivon]

Well, as far as I am concerned, there you have it.

1) When you are using an interface to record, you are also using that interface to play back. You need to send/receive simultaneously.

I've used a USB interface to playback and record simultaneously.

2) When you are using a drive to record, you are also using that drive to play back. You need to send/receive simultaneously.

I've used a USB drive to playback and record simultaneously.

there's obviously some misunderstanding about this "full duplex" business. I've used a USB 2.0 drive to playback 16+ tracks while simultaneously recording 12+ tracks. And, the hard drive didn't even break a sweat.

What setup are you using to do that? I'm interested in purchasing a multitrack mixer for my pc. I've been using an analog mixer with a MobilePre, but I am unable to record more than one stereo track at a time to my pc with this setup. I use Tracktion and Vegas to record. What digital mixer/computer interface would you recommend if I wanted to say, record drums and guitar, but be able to record multiple tracks to my pc simultaneously?

[chris harris]

depending on where I'm working, I use either an RME Fireface 800 or a MOTU pci system. Lately, I've been using Seagate USB2.0 harddrives. Got 'em at Office Max. 250gig for $79 and 320 gig for $99.
I use Cubase SX and DP5 in both studios. Both computers are dual 2.0ghz Mac g5's.

[Ivon]

depending on where I'm working, I use either an RME Fireface 800 or a MOTU pci system. Lately, I've been using Seagate USB2.0 harddrives. Got 'em at Office Max. 250gig for $79 and 320 gig for $99.
I use Cubase SX and DP5 in both studios. Both computers are dual 2.0ghz Mac g5's.

Thank you. It's time to start upgrading for me.

[Andy Peters]

Well, as far as I am concerned, there you have it.

1) When you are using an interface to record, you are also using that interface to play back. You need to send/receive simultaneously.

I've used a USB interface to playback and record simultaneously.

2) When you are using a drive to record, you are also using that drive to play back. You need to send/receive simultaneously.

I've used a USB drive to playback and record simultaneously.

there's obviously some misunderstanding about this "full duplex" business. I've used a USB 2.0 drive to playback 16+ tracks while simultaneously recording 12+ tracks. And, the hard drive didn't even break a sweat.

Indeed there IS some misunderstanding.

It's worth noting that the ATA (or IDE, or whatever it's called) interface between the disk mechanism and the FireWire or USB chipset, or your computer if it's an internal drive, is half duplex. SCSI and Parallel PCI are half-duplex, too.

Whether the interface is full or half duplex isn't really relevant. As long as the interface has enough bandwidth to support what you're trying to do, then you're good.

-a