[Curby]

I apologize first and foremost if this has been discussed already. I did my best to search for a previous topic and came up with nothing. I hate to be the guy that makes a redundant topic.
 
Anyway, I'm curious; can using too many USB devices interfere with a USB DAC? I personally use multiple things beyond just the standard USB keyboard/mouse. I have an external drive, a microphone, etc. Basically, I've been thinking, can these interfere with my DAC's audio playback? I'm running a 955, so processor usage is no concern.
 
Mainly, the concern is USB's ability to interface with all these devices at once. I'm sure the DAC should work fine when these devices are sitting idle, but what happens if I want to perform a file transfer while talking to someone over Vent during a game? Can this cause problems bandwidth-wise? (IE: dropping/clipping audio.) Or what about quality wise? Can it effect the quality of playback? (IE: distortion, jitter, static.)
 
Many thanks to anyone in advance.

 

[FallenAngel]

Directly - Not likely.
Indirectly - Yes, USB root hubs are shared on a motherboard, and putting a USB DAC with other USB devices on the same hub will force software priority processes and multiplexing to work, that's not "ideal".  Next is a potential latency issue if you simply have a lot of USB devices running.
 
As for jitter, distortion, and certainly bandwidth, they are not related.

 

[Curby]

Jitter has to do with timing, correct? Please excuse my ignorance in this area, I've been reading threads on this forum for a few hours now. My brain is totally fried from all the information here.
 
Well, as far as prioritization goes, what problems would likely arise from that? (assuming it even becomes an issue) My first thought was that the DAC would start having to 'wait in line' so to speak for the other devices. Obviously, this isn't good for something you want to be consistently streaming.
 
Quote:

Directly - Not likely.
Indirectly - Yes, USB root hubs are shared on a motherboard, and putting a USB DAC with other USB devices on the same hub will force software priority processes and multiplexing to work, that's not "ideal".  Next is a potential latency issue if you simply have a lot of USB devices running.
 
As for jitter, distortion, and certainly bandwidth, they are not related.

 

[MerlinWerks]

I don't know the answer to your question, but I always try to isolate my usb dac on my PC's port/hub structure. Most PC's USB architecture will have two internal hi-speed hubs and one standard speed hub, usually with 6 ports on each hub. You can use the program USBView located HERE (scroll down ~ 1/4 page) to see what devices are plugged into what hub/port combo. Of course if you have many USB devices then you might not be able to get your dac isolated on it's own hub.

 

[leeperry]

I think it makes sense to put an audio device on its own unshared USB root controller, I've put my mouse and Griffin Powermate on another one.

 

[GuruTech]

hmm that was informative!

thanks for the information

 

[Curby]

EDIT: Cool. According to USBView and Device Manager, I have 7 (or 8, can't remember) Root Hubs. Guess I'm all set.

 

Thanks for that program! That'll be very helpful. In a worst case scenario, I usually have 6 USB devices (including the DAC) and a hub plugged in. (my monitor's integrated USB ports, that is) Given this, I don't think it'll be too difficult to set myself up in a position where this isn't a problem.
 
Still, I'd like to know what the potential problems are with the prioritization of my devices.
Quote:

I don't know the answer to your question, but I always try to isolate my usb dac on my PC's port/hub structure. Most PC's USB architecture will have two internal hi-speed hubs and one standard speed hub, usually with 6 ports on each hub. You can use the program USB View located HERE (scroll down ~ 1/4 page) to see what devices are plugged into what hub/port combo. Of course if you have many USB devices then you might not be able to get your dac isolated on it's own hub.

Makes much sense to me as well, but given that music isn't my only hobby, coming up with a solution may be a tad difficult.
 
Quote:

I think it makes sense to put an audio device on its own unshared USB root controller, I've put my mouse and Griffin Powermate on another one.

 

[Curby]

Bump, still curious about what effects possible problems could have on my audio.