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Firewire/USB Latency when extended/adapted
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Author:  x00011011 [ Sat Dec 08, 2012 4:08 pm ]
Post subject:  Firewire/USB Latency when extended/adapted

Hi everyone. I'm currently using a Digidesign 003 (firewire) and planning to have the DAW in another "machine" room approximately a 35-40' cable run away. Does anyone have any experience regarding quality/latency/problems when running these cables longer-than-spec lengths for audio recording?

I was considering the following solutions:
- Firewire 15' active repeaters/extension cables (may need a couple of these)
- Firewire over Ethernet using baluns

Some such products:
http://www.lindy-usa.com/usb-firewire/f ... nders.html

Also for MIDI, instead of running 16 cables (8 pairs) from my live room to my machine room, I was considering putting a MIDI interface (such as a MOTU) in the live room, while running only the USB back to the Machine Room. But because this is roughly the same distance (35-40'), I'm afraid I would have to use a similar repeater or balun solution for USB as well...?

Author:  Soundman2020 [ Sun Dec 09, 2012 2:42 am ]
Post subject:  Re: Firewire/USB Latency when extended/adapted

The length of the cables is not a problem, and won't cause any latency. The speed of signals traveling on wire is around 50% to 90% of the speed of light, so it travels somewhere between 90 and 150 MILES in a millisecond. For those very short distances you are talking about, the latency is a tiny fraction of a millisecond, somewhere around 50 to 100 nanoseconds. Not a problem.

However, the devices you install to extend your distance (repeaters, switches, extenders, etc.) will very likely have some latency involved, especially if they have to convert from one physical media to another. Since each manufacturer has their own methods for conversion, you should check the specs of the equipment you plan to buy to find out how much extra latency they add. With good equipment, it should not be an issue. The latency should just be a few milliseconds.

Quote:
I was considering the following solutions:
- Firewire 15' active repeaters/extension cables (may need a couple of these)
- Firewire over Ethernet using baluns
I would not do either of those. You would need three repeaters, and each one will introduce it's own issues. Simple baluns might not be reliable for such high speeds. I would bite the bullet and buy some proper firewire extenders. Get a pair plus CAT5 cable. Problem solved. (Not cheap, though.)


Quote:
while running only the USB back to the Machine Room. But because this is roughly the same distance (35-40'), I'm afraid I would have to use a similar repeater or balun solution for USB as well...?
Same answer: a pair of USB extenders and CAT5 cable.

Author:  x00011011 [ Sun Dec 09, 2012 5:56 am ]
Post subject:  Re: Firewire/USB Latency when extended/adapted

Thanks you kindly. Sorry, I think I was using the term balun inappropriately. I found it refers to devices that change between balanced and unbalanced signals. Repeaters vs Ethernet Extenders is what I was meaning to convey.

Do you have a recommendation for particular products with acceptable latency or what's your opinion on these products?

The Newnex FireNEX-CAT5-S800 800 Mbps 1394b Cat5 Repeater
http://ntcdistributing.com/products/fir ... MgodJkUAsQ

Gefen GTB-USB2.0-4LR-BLK USB 2.0 Long Range 4-Port Extender over CAT5 up to 330ft
https://hdwise.com/product.php?producti ... Mgod_H0A2w

Author:  x00011011 [ Thu Dec 13, 2012 5:06 am ]
Post subject:  Re: Firewire/USB Latency when extended/adapted

Has anyone successfully used Firewire/USB extenders (over ethernet) between your Interfaces and DAW, without a problem in latency, or other?

I would really like to know what models you have used. Please share...

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