Multiple monitors and audio ... how many docking stations do I need ?


#1

Good evening,

I’m trying to determine how many of the docking stations (the higher res ones) I would need for my use case. I’m using a Toshiba Satellite A6645, and plan on driving 1x HP 24" 1080, 1x Dell … uhm, 19" I believe, and possibly a third Dell 15".

This will be for DAW use so I don’t have large graphics needs (other than the occasional Youtube/Netflix) but I do plan on running them at the highest resolution possible. They all have VGA and DVI inputs, and the HP 24" also has DisplayPort ( I know …) … so how many docking stations would I actually need ?

Also, I do plan on routing digital audio out through the docking station. Could you tell me a bit about the ADAC you use ? Can I presume it would be at least as high quality as in the Toshiba (not that laptops use particularly high quality ADACs).

If I’m running two or three monitors plus audio do I stand a chance of lagging or distorting the audio ?

Thank you !


#2

Hi Matt,

Thanks for asking ahead!

The Toshiba Satellite A665 is a nice laptop - plenty of horsepower for USB graphics with its Core i5/7 class processor.

Assuming you’ll have all monitors connected through USB (so you have single-cable docking to the 3 external monitors), you’ll want:

1 Plugable UD-160-A laptop dock http://plugable.com/products/ud-160-a/
2 Plugable UGA-2K-A or UGA-165 adapters [http://plugable.com/products/uga-165/…](http://plugable.com/products/uga-165/(the) only difference between the two is maximum resolution; both can support 1920x1080).

And as long as you have VGA or DVI connectors on every monitor, and they’re all 1920x1080 or lower resolution (which I believe is the case), you’ll just plug the two graphics adapters into the dock, and have single-USB-cable connectivity back to the laptop.

In terms of audio, we use the C-Media CM6300 chipset. Here’s the full specs: http://www.cmedia.com.tw/ProductsDeta…

One thing to note about the audio is it’s set for high-power output (for unpowered speakers). For people with amplifiers and powered speakers, that sometimes causes frustration with adjustability of volume. Check out this post for solutions: http://plugable.com/2010/10/28/howto-…

In terms of audio quality, USB audio on Windows is good for consumer use, but it’s not targeted at professional use. Latencies that most people wouldn’t notice, get noticed in the more professional use cases.

And in terms of running audio with 3 monitors - USB audio uses isoch transfers, which actually reserve bandwidth on the USB bus. So when the bus is constrained (which can easily happen in short bursts), the audio will effectively get priority over video (DIsplayLink graphics uses bulk transfers, which are scheduled by USB on an as available basis)-- so you’ll notice video lags before hearing any audio effects.

Hope that background helps. Thanks again!
Bernie


#3

I also wish to use this as a third monitor in my DAW (Cubase) set-up. I want to make sure that there will not be any noticeable latency between the audio (which will come from a separate interface) and the video displayed on the monitor. What do you think?


#4

Hi Gabriel,

The amount of latency with USB graphics controllers depends on how many pixels are changing on the screen (because that’s the only thing that generates USB traffic - a static image generates none).

There is no full-frame buffering or anything - only transfer time of changed pixels over the USB bus (via bulk packets).

So mouse movement is indistinguishable from a normal monitor. It’s instantaneous. Window drags and normal application drawing also isn’t normally noticeable, even with a discerning eye. Scrolling a big window like a web page is one of the first situations where some lag (or temporary interlacing to eliminate lag) may be noticeable. And, finally, we don’t recommend motion video or 3D gaming on the USB 2.0 attached display - many users will say it’s fine, but discerning eyes will see frame latency and/or dropped frames and other artifacts. That’s why we always recommend playing motion video or 3D games on the main (non-USB screen).

So for your Cubase setup, it’s difficult to tell. I would suspect that with a modern machine (Core i3/5/7) and a monitor that’s not super high resolution (1650x1080 or 1440x900), that the latency isn’t significantly different between the USB attached display and your main display – but it will depend on what’s being rendered, too.

Hope that background helps. All this is subjective, so we try to set expectations carefully – in the end, people usually end up being amazed at how well USB graphics adapters work (especially with several of them driving several displays).

Thanks and best wishes!
Bernie


#5