USB, Firewire or Optical

[Niner]

On Channel D's (Pure Music) website they have quite a lengthy and informative "getting started" section where they discuss that you should have the opposite connection to your external hard drive as your DAC. For instance if you run USB to your HDD you should run Optical or firewire to your DAC or visa versa.

 

The reason I'm asking is I'm in the market for an external HDD. In my short search finding one with firewire is more difficult and expensive.

Also, from reading several posts, it seems that USB is the connection of choice for the DAC. SO that mean finding a HDD with firewire.

 

Does any one have any validation for there reasoning.

Also any recommendations for a firewire HDD.

 

Thanks.

 

[scobek]

Check out the Seagate GoFlex Desk drives. Although USB, you can get a a relatively cheap Firewire 800 "Desktop Adapter" (with 1.2m FW cable included in the pack).

 

[SteveChicago]

I use a Glyph 1.5TB HDD via Firewire. It also has USB 2.0. The Glyphs are a bit pricey but great build quality and professional design. The FW and USB gives you flexibility.

 

[bottlerocket]

http://eshop.macsales.com/shop/firewire/on-the-go

 

This one has firewire 400 and 800 and USB 2.0 so you are completely covered and the firewire compliant version is only $20 more than the USB only. You can also use the drive as an internal drive replacement if you ever wanted to, as the case is very easy to get into. Or you could replace the drive later with a larger one and use the same case. I bought one of these cases with an internal replacement drive a few years ago and stuck the old 80 gig drive in it and use it as portable drive.

 

 

 

 

 

[krass]

you ask for the reasoning; I think it's simply to separate different types of traffic from each other on the computer: eg) have the FireWire bus servicing HDD I/O, and let the USB bus service the I/O with the DAC (or vice versa of course).

 

That way the "load" on each bus is minimized and performance of each bus maximized, supposedly better sound (by the same reasoning on MacMini it is suggested to check which internal users are using each of the 2 USB internal busses and put your audio service on the least used).

 

I cannot comment on whether there is any sonic difference as Ive never experimented.

 

[SteveChicago]

I should add, FWIW, that in my system I daisy chain via FW from the MAC Mini to the Glyph and from the Glyph to the Weiss AFI1 interface, which is also FW. Works flawlessly and I have no negative SQ issues. The interface is connected to the DAC via AES/EBU. But yes, if your DAC has USB in you will want to use FW between your computer and your HDD.

 

[losingmyreligion]

 

"you should have the opposite connection to your external hard drive as your DAC"

 

That makes sense if one has a USB DAC.

 

For Firewire DAC, one can (and should, IMO) still use a Firewire interface to the hard disk drive, without ill effect.

 

The logic for using Firewire disk access with a USB DAC is well known. Basically, the USB bus uses the central processor for everything. Contention becomes an issue, which is why it's important to connect your DAC to a particular USB port.

 

 

Firewire has a dedicated chipset that lessens the load on the CPU, while managing traffic from daisy-chained Firewire devices (peer-to-peer protocol). Firewire was designed for just such activity. USB was designed for connecting to peripherals, such as mice and printers.

 

Using a USB hard drive will only add to the load on the CPU, and thereby compete with the music player, whose primary method of improving the sound is to lessen undesired CPU activity.

 

so, use a Firewire (or eSata) disk drive, never USB.

 

 

clay

 

 

 

 

 

 

 

 

 

 

 

[Dj]

"Using a USB hard drive will only add to the load on the CPU, and thereby compete with the music player, whose primary method of improving the sound is to lessen undesired CPU activity."

 

I am using the USB ports on both sides of my MacBook Air and have never seen a CPU load of more than 0.7% for playing back FLAC files with Audirvana. That CPU load is nothing and won't do any harm to the SQ. But just to give in to the marketing hype "you have to use something else than USB" I will buy a Lacie Thunderbolt drive since I don't have any Firewire port on my MacBook Air.

 

[losingmyreligion]

 

 

If you don't understand (or just dislike) my use of the phrase "add to the load", please replace it with "increase undesired CPU activity".

 

It's generally accepted that the mechanism by which software players improve sonics is by eliminating unwanted (i.e. undesirable) CPU activity, as this lessens the noise generated by the hardware.

 

have a great day *

 

[Dj]

I understand what a CPU load is as I am an IT specialist. That is my day to day work. Just wanted to tell you that Using USB ports does not add any significant load to CPU. A 0.7% CPU load using Audirvana while reading files from the USB storage and playing back FLAC files is next to nothing.

 

I thought maybe you have read it somewhere not to use USB for DAC and storage and I wanted to share my experience. Don't take it personal.

 

Amarra uses around 13% CPU power idle without any playback and I stopped using it.

 

 

[losingmyreligion]

 

"I thought maybe you have read it somewhere not to use USB for DAC and storage and I wanted to share my experience. Don't take it personal."

 

It's generally accepted here on CA (and other forums) that - for best sonics - one needs to be careful which USB port to use, and also (as Rob Robinson of ChannelD says) to use Firewire or some other interface when accessing disk drives when using a USB DAC.

 

If you want to challenge that view, you'll need to convince the majority of posters here on CA. Given that, there's nothing for me to take personal.

 

 

The point of my post was to challenge the view that when using a Firewire DAC, one should use a USB disk drive. That's not been my experience. Nor is it my belief, for the reasons mentioned.

 

If I had a dollar for every time a self proclaimed IT "expert" thought he knew better than the collective wisdom of this forum, I could afford a dCS DAC.

 

 

 

 

[Dj]

It is clear that you have read something somewhere and put it in any thread you can.

 

I am not a self proclaimed IT expert but actually I was 10 years ago IBM's performance tuner. Checking CPU load has been my work for very long time.

 

I read the same blah what you are giving from yourself about using USB and went and tested it myself and actually took screen shots and published it in another thread here on CA. Most likely the recommendation is no more valid with modern computers. Maybe your experts tried it with computers they fed with kerosine in the 80s.

 

Obviously you don't understand that a 0.7% CPU load can not and will not have any sonic effect.

 

You may not have the money but I hope you have a USB DAC and a USB storage. Do the test yourself and stop citing other people. It is not bad to have your own test, opinion and knowledge and stop aping other people.

 

[losingmyreligion]

It is clear that you do not (yet) understand what I posted.

 

You're still hung up on the word "load", and assuming that I (and others) are claiming that the measured load on the CPU correlates to sonic improvement.

 

 

As I posted earlier, "If you don't understand (or just dislike) my use of the phrase "add to the load", please replace it with "increase undesired CPU activity".

 

Thus, the objectionable phrase (which you quoted earlier) would then read:

 

"Using a USB hard drive will only increase undesired activity on the CPU, and thereby compete with the music player, whose primary method of improving the sound is to lessen undesired CPU activity."

 

 

Then go and ask Damien why his software sounds better than iTunes.

 

have a great evening *

 

 

[barrows]

"Then go and ask Damien why his software sounds better than iTunes.

 

have a great evening *"

 

LOL, I hope this expert can explain the sonic effects of different playback software, I am still waiting for that...

 

 

 

[Dj]

barrows,

 

Nobody spoke from being an expert here. You are the expert!

 

I only reported my test.

 

[Dj]

Yep, You don't understand what I am saying. I did the test of using both USB ports and there was no increased activity on the CPU. I could take screen shots and post it tomorrow.

 

I don't need to ask Damien why his software sounds better I said already that I use only his software because of low CPU usage. Learn reading and stop being upset because someone challenged your citation.

 

[losingmyreligion]

For what it's worth,

 

Damien published this in his "white paper" at www.amr-audio.co.uk

 

"Furthermore, ... the computer load (and its variations) has an impact on sound quality. Minimizing such current demands and sources of interferences is key:

 

...

 

• Minimizing synchronous CPU load taken for the audio data streaming operations. In addition to reduce jitter, this also helps to reduce audible RF interference patterns, ..."

 

it's an interesting read, you might enjoy it.

 

clay

 

 

[Dj]

The reason why I chose Audirvana was because of low CPU load. When the CPU load is low it stay cold and there won't be any need for the fan to run and stay less noisy.

 

I didn't read Damien's white paper yet. I just did what I am used to do. Testing!

 

[losingmyreligion]

"I did the test of using both USB ports.."

 

Testing the CPU load will not measure contention between USB ports, which is the rationale most often cited for not using USB drives when using a USB DAC.

 

 

 

 

 

 

[Dj]

How do you measure contention between USB ports? I am sure you seriously have no clue what are you talking about. Are you a salesman or so? OK, I stop here.

 

[barrows]

I have read Damian's writings. Still no real facts as far as I can tell, all we really have is speculation on what really matters with playback software. This does not bother me so much, I find that both Audirvana and Pure Music sound really good, and could be happy using either.

 

"Nobody spoke from being an expert here. You are the expert!"

 

Thanks, but no thanks! I am no expert when it comes to computers and software... That is why I am honestly, always trying to learn more from those who know more about computers than I do. Like many things though, when it comes to audio performance, it appears to me that the more we "know" the less we know...

 

 

 

[losingmyreligion]

 

I just happened to notice this at AA, and thought you might be interested.

 

Tony Lauck was complimentary of Damien's "white paper" in this thread,

 

http://www.audioasylum.com/forums/pcaudio/messages/9/99062.html

 

... saying "the link described what goes on in computer systems used with audio. It said nothing more or less than what many of us have said. I don't disagree with these facts. At issue is what to do about them."

 

 

clay

 

[Audioseduction]

I myself am useing the USB 2 port for my DAC and the USB 3 port for the external Seagate 3TB USB 3 hard drive. The USB 3 port provides 5Gbps throughput. Each port has it's on bus so no data congestion issue. This setup is working extreamly well for my digital playback configuration.

 

[DM]

Stick with USB solution. Firewire will be faced out in consumer market.

 

My friend who is working in a electronic design company and certificated by Apple, Apple at the end of last year issued internal technical document which stated that "For new design, use USB interface. Firewire is only for exiting design and compatibility reason."

 

Also according to him, Asych USB is better than Firewire by design if implemented correctly.

 

Finally, forget Optical (I meant Toslink), which is the worst possible digital connection you can have. For SPDIF, the best is 75ohm coaxial cable with BNC connector, then it is the 110ohm with XLR connector, even the RCA coaxial cable is better than Optical.

 

[losingmyreligion]

 

"Also according to him, Asych USB is better than Firewire by design if implemented correctly."

 

I've been following the issues related to Async USB / Firewire since Gordon Rankin developed the first audiophile quality Async USB DAC.

 

I've owned 4 DACs for computer audiophile playback. All are Asynchronous - two Metric Halo Firewire DACs and two Wavelength USB DACs.

 

I submit that there's not a shred of evidence to support your friend's notion that Async USB "is better than Firewire by design if implemented correctly."

 

If one is better than the other, in my opinion, the evidence points in the other direction.

 

There are an awful lot of things that even the best engineers in computer audio haven't sorted out as it relates to the best computer audio performance via Async USB or Async Firewire. Unless your friend has experience with SOTA computer audio playback/recording, I'm not sure what value his opinion would have to discussions here regarding the superiority of one versus another.

 

BTW, Firewire is being phased out by Apple in favor of Thunderbolt, which is a superior design (as compared to Firewire and USB). I'll be able to use my world class LIO-8 Firewire DAC well into the next decade if I want, and performance will be improved once Thunderbolt Optical is released.

 

respectfully,

clay