Music Streaming through a self-powered USB Hub Question

[Fireblade]

Hi! I'm currently streaming music from my toshiba laptop (which offers two USB ports) to an HRT MS II+ USB/DAC(which demands 400 mA). I'm planning to run an external HDD from the second USB port to store my music files and to run the Foobar2000 player from that external drive, to avoid the internal HDD's noises.

 

The problem is my laptop's USB bus may be struggling to keep up demand from both ports at the same time. Thus, I was suggested to use a dedicated self-powered USB hub only for the MS II + and alleviate the host from the burden of HS to FS translation demands.

 

But I wonder if the addition of a self-powered hub between the host computer and the USB/DAC would contribute to some sound degradation of the player's signal going to the DAC.

 

If not, can you suggest a good self-powered model I should get?

 

If you think this is not such a good idea, could you provide an alternative?

 

I do not have FireWire nor Ethernet ports, except for a thin, longish 3rd port which shows a symbol that seems like an 'SD', which I'm not familiar with.

 

Thanks to all for your support.

 

 

 

[senmurv76]

You say " .. USB bus may be struggling .." .. can you elaborate further on what makes you think the USB bus is struggling?

 

I cannot recommend any self-powered USB hubs, but what I can tell you is that the total power output of the hub is usually divided between the number of ports you have in the hub.

 

For example, if you buy a 2.0 amp 7-port hub, each port will only be able to draw just below 0.3 amp of power which may not be sufficient to power some USB devices. Now if you buy the 4-port version of the same hub, each port will have 0.5 amp of power to utilize.

 

[bikemig]

I tried running an HRT MS II off a usb bus and was not too happy with the results (some pops and so forth). Your mileage may vary and since USB hubs are cheap, it is worth a try. I know with my mac laptop, one of the USB ports has more power than the other so that may be something worth exploring. Also why not simply have an external hard drive that has its own power brick rather than running it off the usb port?

 

[esldude]

http://www.monoprice.com/products/product.asp?c_id=103&cp_id=10307&cs_id=1030702&p_id=5328&seq=1&format=4

 

Less than $15. 7 port powered hub with 2 amp output at 5 volts. Obviously not really enough for all 7 if loaded heavily. But plenty for one or two or even three USB devices.

 

I don't think this will degrade your sound.

 

[Mark Powell]

Even though he uses one of these Mac things.

 

Much better to buy a USB disk drive with its own power supply. They are cheap enough.

 

[senmurv76]

http://www.monoprice.com/products/product.asp?c_id=103&cp_id=10307&cs_id... Less than $15. 7 port powered hub with 2 amp output at 5 volts. Obviously not really enough for all 7 if loaded heavily. But plenty for one or two or even three USB devices. I don't think this will degrade your sound.

 

As I stated earlier you got to be careful here. The 7 port USB hub I have, divides the available current equally between the ports. I.e. I can utilize only 1/7 of the total power, regardless of how many of the ports are being utilized. The hub I have outputs a total of 2 amps. However, I am not able to drive a bus-powered USB drive which requires 1 amp current, even if the USB drive is the only peripheral connected to the hub. This may be specific to my hub, though I have heard this is typical of all USB hubs.

 

 

[Fireblade]

Hi senmurv76! When I will be running both devices (HRT MS II+ and ext. HDD) while streaming music from the ext. drive through the DAC (both USB ports connected), the USB root may have problems providing energy for both high energy demands at the same time.

 

Each port in my laptop is rated at 500 mA. The DAC alone would nominally use 80% of that, so this one is bearly feasible. But, I don't know how much power an ext. HDD would demand.

 

Furthermore, I was adviced by HRT that the demands upon the hub root for HS to FS translation may be too much for the host to meet.

 

One evident solution is to use a self-powered USB Hub. The other is to use a self-powered ext. HDD. I'm not familiar with either approach, so I need your advice on which way to go.

 

Thanks for your assistance.

 

 

[Fireblade]

Thank you all for your assistance! I think so far the answer may be to get a self-powered ext. HDD and limit the demands from the USB root only from the DAC.

 

In addition to the energy/translation issues involved, this approach would also ensure there's no further sound degradation throuh the USB hub, connecting the DAC directly to the host's USB port.

 

Let me ask you one more thing, though: Are there advantages in sound quality by playing Foobar2000 from the ext. drive rather than using the internal drive? If not, I could simply pre-select a set of files from the ext. drive and transfer them to the internal drive before streaming.

 

What do you think? Thanks again for your support.

 

 

[Mark Powell]

I don't know, but those more expert than me *say* it is best not to have the music player and the music files on the same disk. So leave Foobar on the internal disk.

 

[Fireblade]

Hi Mark! To make sure I follow, you mean having Foobar2000 working from the internal drive, but calling the files to be played from the Ext. HDD, correct?

 

This would assume that there are sound benefits by not running the internal HDD for playing, as I have read.

 

Currently, I've increased Foobar2000's playback buffer to 500,000 Kbs to ensure the player runs the files from RAM (to avoid internal HDD noises getting through). Presumably, running the files from the future external drive would get rid of this problem altogether. Am I right?

 

Thanks for your assistance

 

[Quest]

i am not sure if this will help you at all, but i was in the search for a usb hub just awhile ago and bought a vaunix.

 

http://www.vaunix.com/products/high-quality-usb-hub/overview.cfm

 

i had two problems that i solved with it: (i) ground issue with my usb devices (ii) for some reason, my dac causes my PC to freeze during boot-up sometimes (i have to disconnect and re-connect). i'm wondering if it is power draw but in any case it's solved now.

 

the vaunix is not cheap so be aware ymmv. i did feel my sound quality improve with it in the chain though.

 

[Mark Powell]

Yes, that is exactly what I am saying.

 

However, I am only repeating the views of some others. Personally, I have JRiver on the internal disk, and my music on a wired ethernet NAS, though my broadband router. Works fine, and I am unable to tell any difference if I bring some music files to the internal disk and play from there.

 

But what they say makes sense. Also putting the player out on the external disk just complicates things.

 

What you don't want, however, is the music coming in from a disk on one USB port and the output to the DAC going out on another. A lot of people say that is bad, and it makes sense also. That is why I use a NAS. I don't have a USB drive so cannot try it any other way than what I am using.

 

[Fireblade]

I was planning to get this one:

 

http://www.bhphotovideo.com/c/product/655841-REG/Western_Digital_WDBAAU0015HBK_NESN_1_5TB_Elements_Desktop_Hard.html

 

But this is a desktop ext. HDD, so I'm not sure if the interface would be consistent with the laptop interface. I can't find self-powered ext. HDD for laptops. Any suggestions?

 

Thanks,

 

[Mark Powell]

It does not have to be a 'laptop' drive. Any self powered USB drive will do.

 

Don't drop it. Unless you have a good back up process in place!

 

[Fireblade]

So, essentially, I need to transfer the selected files for a listening session from the ext. HDD and place them in the internal disk, and then start the player to stream via the 2nd USB port - DAC, correct? This would make the processes non-concomitant, avoiding the problems you mentioned (USB port to USB port).

 

This would be fine, except the internal HDD noises would be possibly getting through the signal. I don't have a NAS, which I think is the best way of setting this up.

 

If I settle with the procedure outlined in the first paragraph of this message, I don't even need a self-powered ext. drive, as both processes would not be concomitant anyway.

 

Maybe running the files with a high pre-specified playback buffer on Foobar2000, from my internal disk, is the way to go in my case. This would eliminate the issues of internal HDD noises (files being played from RAM).

 

Thanks again for your support.

 

 

 

 

 

[Mark Powell]

Try it with 'in one USB port and out the other' If it's ok, no problem. Don't mess about with constant transfer of files from one to the other. Life's too short

 

[Fireblade]

Got it, thanks. I'll order the previously referenced self-powered ext. HDD then.

 

[drystream]

It sounds like your concerns will be addressed by getting a self-powered HDD, but to answer your initial question, I haven't noticed any problems with playback using a powered USB hub.

 

I was having some unsolved problem using my computer's USB ports so I picked up this hub: http://www.coolgear.com/productdetails1.cfm?sku=USBG-4U2ML

 

It uses a 5A power supply which must be purchased separately.

 

[esldude]

As I stated earlier you got to be careful here. The 7 port USB hub I have, divides the available current equally between the ports. I.e. I can utilize only 1/7 of the total power, regardless of how many of the ports are being utilized. The hub I have outputs a total of 2 amps. However, I am not able to drive a bus-powered USB drive which requires 1 amp current, even if the USB drive is the only peripheral connected to the hub. This may be specific to my hub, though I have heard this is typical of all USB hubs.

 

Typically, USB ports should provide 500 ma of current to meet 2.0 spec. I did not mean to imply a 2 amp 7 port hub would provide you with 2 amps if you hook up one device. However, that one device on one port would use only .5 amps and that means the supplying wall wart is not being overtaxed. Even 3 or theoretically 4 ports would still be within the supply's 2 amp capability. If you have a device that draws more than that it should have more than one USB plug (like some bus powered DVD drives) or have its own power supply. Of course some devices like laptops and netbooks don't always have the ability to put out 500 ma per USB port if all are filled like they should. Or you get people adding external bus powered hubs and over loading the ports.

 

Even this is now somewhat murky as they have revised aspects of USB 2.0 standard to accommodate USB chargers used in phones, music players, etc. etc. Some of those special ports and such are rated up to 1.5 amps per USB 2.0 port.

 

Assuming the OP's DAC meets the spec and doesn't draw more than 500 ma the powered hub would work for his needs. Even the cheap option I linked to has less HF noise on the ports of the hub than coming out of a computer when powered.

 

[phofman]

Just get it (it costs a few bucks) and try. If you hear no difference, good for you. And if you do - a USB hub is always handy to have around.

 

[Fireblade]

Mark said: Try it with 'in one USB port and out the other' If it's ok, no problem. Don't mess about with constant transfer of files from one to the other. Life's too short

 

Unfortunately, I was adviced against this by HRT, as detrimental to the host's USB root in allocating limited resources to competing demands for both the ext. HDD and the MS II+ requirements.

 

The good news is, I can just ensure these two processes do not concur. So, before playing files, I would make a pre-selection. Once in RAM, these files would be streamed down the USB/DAC. The two USB processes would thus be separated in time, therefore non-competing anymore. This also ensures no internal HDD noises getting through, as playing would be exclusively out or RAM realm (no HDD processing required).

 

It's not too bad. I have done this lately with excellent results (using MS II not MS II+ yet, as it has not arrived.)

 

I will try the self-powered USB hub also, to see if there are improvements on the very sporadic stuttering I get even with output buffer settings as low as 50Ms on Foobar2000. We'll see.

 

 

 

[Fireblade]

Thanks so much for all your very valuable inputs, guys. Once I get those two pieces connected, I'll report back. Oh, drystream, I will take a look at that self-powered USB hub you have suggested. Sounds like what I need to try for further improvements. Cheers!

 

[Fireblade]

Got it, esldude. Agreed. Fortunately, the MS II+ will require a nominal current of 400 mA, so well within the 500 mA spec for my laptop 2.0 USB ports. The key here is to dedicate the USB root to the MS II+ exclusively, while it's streaming.

 

Thanks for the explanation.