KVR Audio

lebaron · Post by **lebaron** » Thu Feb 23, 2006 9:39 pm

To put things in perspective, the best sustained data rate you can get out of a modern 7200 rpm drive is approx. 75 MB/s, while the fastest external drives (no matter if USB 2.0 or Firewire) give you between 20 and 25 MB/s.

480Mb/s is about 218 times more than the bit rate required for a 24/96 track. If 200+ tracks is enough for you then USB2 is OK.

Can someone clarify this for us unfortunate individuals who consider it an act of bravery just looking at hardware specs, let alone actually understanding them.

What's the difference between the declared transfer rate of USB 2.0 of 480 Mbs and the effective or actual tranfer rate of ~20 Mbs? Or, why CAN'T we get 480 Mbs streaming from our external USB2.0 harddrives?

Thanks

musiclinks · Post by **musiclinks** » Thu Feb 23, 2006 9:58 pm

spaceman wrote:I DON'T KNOW IF A USB 2 DRIVE IS ENOUGH FOR AUDIO

WHAT DOES THE REST OF THE PEOPLE HERE THINK ABOUT THE SUBJECT?

DOES MY BUM LOOK BIG IN THIS?

LOOK AT ME! LOOK AT ME! DON'T LOOK AT ME!
I'M SHY!!

thanks for mocking me:roll:

to everyone else, thanks for the feedback. I was planning to run the audio off the internal drive, and if I need video playback, do that from the ext drive. I would also run samples off another drive (I would have 2 ext drives.)

pj geerlings · Post by **pj geerlings** » Thu Feb 23, 2006 9:59 pm

FWIW: 480Mb/s is approximately 60MB/s (there is overhead in the protocol)

b = bits
B = Bytes

susiwong · Post by **susiwong** » Thu Feb 23, 2006 11:03 pm

pj is correct, that's the first reason for the "discrepancy".
But even more limiting is the maximum speed of the chipsets used to transform the USB or Firewire protocol to IDE or SATA. Those chipsets sit on a little circuit board inside the external enclosures and they give you at best 25 MB/s.
Imagine a big, empty highway.
Good for at least 400 km/h. (USB/Firewire bus)
Your driving skills are good enough for, say, 200 km/h. (HD transfer rate)
And you're driving a big, fat, ferrari red tractor with a top speed of 75 km/h. (the chipset in the external box)
So what top speed are you expecting to get ?
Correct, 75 km/h.
The nice big, empty highway doesn't help you at all.
Of course the manufacturers, if giving away any data about their external enclosures at all, tend to only give you the theoretical max bus speed, which is not at all relevant in this scenario.
Please forgive me the silly example, I hope it helps to explain those rather theoretical dependencies a bit.
Cheers,
susiwong

eduardo_b · Post by **eduardo_b** » Fri Feb 24, 2006 3:00 am

musiclinks wrote:Hello All,

I'm going to be getting a new system shortly (hopefully), and wanted to know if I can stick with one internal drive and use usb 2 external sataII or ATA drives for audio. Are the external drives fast enough for audio or is internal SATA2 the way to go?

I don't know about recording to an external hard drive, but my Maxtor 250 gig USB external serves up samples into Kompakt and Kontakt and other romplers without problem. NI stuff uses DFD (direct from drive) and seems just fine to me.

Spyda KB · Post by **Spyda KB** » Fri Feb 24, 2006 4:50 pm

musiclinks wrote:I was planning to run the audio off the internal drive, and if I need video playback, do that from the ext drive. I would also run samples off another drive (I would have 2 ext drives.)

If it was up to me I would use the external drive for audio and use the internal drive for video. Streaming video from external drives would probably be more taxing on the system as opposed to streaming audio.

- KB

rockstar_not · Post by **rockstar_not** » Fri Feb 24, 2006 5:19 pm

I record and playback 2 channel 24 bit 48000 Hz data to a 5400 rpm 2.5" Toshiba drive in a USB 2.0 enclosure with no problems whatsoever. Been doing this for over a year.

-Scott

Hink · Post by **Hink** » Fri Feb 24, 2006 5:42 pm

I'm using a 200 gig external hard drive for my dfhs samples, music projects and now my new bass samples...I use it with firewire, though I could use usb2.0 because I have two free ports...it has not caused me any noticeable problems of any kind, and no signs of speed issues...

musiclinks · Post by **musiclinks** » Fri Feb 24, 2006 5:54 pm

Spyda KB wrote:
musiclinks wrote:I was planning to run the audio off the internal drive, and if I need video playback, do that from the ext drive. I would also run samples off another drive (I would have 2 ext drives.)
If it was up to me I would use the external drive for audio and use the internal drive for video. Streaming video from external drives would probably be more taxing on the system as opposed to streaming audio.

- KB

good point, I will try either one to see what works best for me.

pdxindy · Post by **pdxindy** » Sat Feb 25, 2006 8:44 pm

susiwong wrote:pj is correct, that's the first reason for the "discrepancy".
But even more limiting is the maximum speed of the chipsets used to transform the USB or Firewire protocol to IDE or SATA. Those chipsets sit on a little circuit board inside the external enclosures and they give you at best 25 MB/s.
Imagine a big, empty highway.
Good for at least 400 km/h. (USB/Firewire bus)
Your driving skills are good enough for, say, 200 km/h. (HD transfer rate)
And you're driving a big, fat, ferrari red tractor with a top speed of 75 km/h. (the chipset in the external box)
So what top speed are you expecting to get ?
Correct, 75 km/h.
The nice big, empty highway doesn't help you at all.
Of course the manufacturers, if giving away any data about their external enclosures at all, tend to only give you the theoretical max bus speed, which is not at all relevant in this scenario.
Please forgive me the silly example, I hope it helps to explain those rather theoretical dependencies a bit.
Cheers,
susiwong

DV is 25 MBs and any external drive/case combo these days captures DV fine, so it seems like the limit you are describing must be a bit higher. If it were 25 at best, then there would be constant capturing failures.

And of course one can have more than 1 external drive.

musiclinks · Post by **musiclinks** » Sat Feb 25, 2006 9:18 pm

pdxindy wrote:
susiwong wrote:pj is correct, that's the first reason for the "discrepancy".
But even more limiting is the maximum speed of the chipsets used to transform the USB or Firewire protocol to IDE or SATA. Those chipsets sit on a little circuit board inside the external enclosures and they give you at best 25 MB/s.
Imagine a big, empty highway.
Good for at least 400 km/h. (USB/Firewire bus)
Your driving skills are good enough for, say, 200 km/h. (HD transfer rate)
And you're driving a big, fat, ferrari red tractor with a top speed of 75 km/h. (the chipset in the external box)
So what top speed are you expecting to get ?
Correct, 75 km/h.
The nice big, empty highway doesn't help you at all.
Of course the manufacturers, if giving away any data about their external enclosures at all, tend to only give you the theoretical max bus speed, which is not at all relevant in this scenario.
Please forgive me the silly example, I hope it helps to explain those rather theoretical dependencies a bit.
Cheers,
susiwong
DV is 25 MBs and any external drive/case combo these days captures DV fine, so it seems like the limit you are describing must be a bit higher. If it were 25 at best, then there would be constant capturing failures.

And of course one can have more than 1 external drive.

I have to agree, 25 MB/s sounds to low, even with bottlenecks, I'll have to research this some more. But judging from the boards ppl seem to be having few issues using ext drives.

jupiter8 · Post by **jupiter8** » Sat Feb 25, 2006 9:23 pm

DV is NOT 25 MB/s. Uncompressed videos is.
DV is 3.6 MB/s.

pdxindy · Post by **pdxindy** » Sat Feb 25, 2006 10:22 pm

jupiter8 wrote:DV is NOT 25 MB/s. Uncompressed videos is.
DV is 3.6 MB/s.

you're right... DV is 25 Mbit/s ... I got confused

ARE EXTERNAL USB 2 DRIVES FAST ENOUGH FOR AUDIO??