Long USB Solutions

[kittonian]

First off a few corrections/updates:

1. The TI2 is USB 2.0 not 1.1
2. The max spec length of a single non-active USB 2.0 cable is 16.5ft
3. Active USB extensions are made so that the signal transmits over longer lengths without loss (at least the good ones). Will there be an increase in latency, perhaps, but it should be fairly negligible when we're only talking about 25ft (only 9ft over the max spec of non-active cabling).

That all being said, and having been in both the pro audio and technology industries for many years, I would say that it is the software that is the issue. I'll explain why.

• If I can plug in the USB cable with the extension and achieve flawless playback with no discernible increase in latency, why is it losing communication after not being used for a few hours?
• Why can I play the unit just fine, have it sync with the USB clock, and have it automatically (through the plug-in) pull up the correct patch(s) yet it won't show me the proper names in the software (but it will on the hardware)?

I truly love the Virus and when you have the TI2 close enough to the computer and on its own USB bus, at least with PT|HD, it works flawlessly. This is also one of the reasons we are an Access dealer. I own and use a TI2 Keyboard personally and wanted to ensure that the joy I get from this instrument is also offered to our customers.

My problem is that if one of the big plusses is going to be software integration, perhaps working on issues such as these would be in order. Most pro studios have a separate machine room where the length would need to be far greater than the 25ft I am dealing with. Even if Access came out with their own USB extension solution, that they developed with their software to ensure rock solid reliability, I would buy it in a heartbeat. At that point they could say, no 3rd party solutions will be supported, and honestly I wouldn't have an issue with that, even if their solution was a bit expensive.

[namnibor]

Originally Posted by kittonian

First off a few corrections/updates:

1. The TI2 is USB 2.0 not 1.1
2. The max spec length of a single non-active USB 2.0 cable is 16.5ft
3. Active USB extensions are made so that the signal transmits over longer lengths without loss (at least the good ones). Will there be an increase in latency, perhaps, but it should be fairly negligible when we're only talking about 25ft (only 9ft over the max spec of non-active cabling).

That all being said, and having been in both the pro audio and technology industries for many years, I would say that it is the software that is the issue. I'll explain why.

• If I can plug in the USB cable with the extension and achieve flawless playback with no discernible increase in latency, why is it losing communication after not being used for a few hours?
• Why can I play the unit just fine, have it sync with the USB clock, and have it automatically (through the plug-in) pull up the correct patch(s) yet it won't show me the proper names in the software (but it will on the hardware)?

I truly love the Virus and when you have the TI2 close enough to the computer and on its own USB bus, at least with PT|HD, it works flawlessly. This is also one of the reasons we are an Access dealer. I own and use a TI2 Keyboard personally and wanted to ensure that the joy I get from this instrument is also offered to our customers.

My problem is that if one of the big plusses is going to be software integration, perhaps working on issues such as these would be in order. Most pro studios have a separate machine room where the length would need to be far greater than the 25ft I am dealing with. Even if Access came out with their own USB extension solution, that they developed with their software to ensure rock solid reliability, I would buy it in a heartbeat. At that point they could say, no 3rd party solutions will be supported, and honestly I wouldn't have an issue with that, even if their solution was a bit expensive.

All good info! I also learned something from your post that I think via mal-informative posts about the Ti line, had always heard the whole Ti Line was USB 1.x and it never really made sense to me that in a version 2 (Ti2) they would continue to utilize lower bandwidth rather than USB 2.0....this makes me actually anticipate whatever Access releases next because by then there would be Ti2 or even a 'Polar' at a better used price when people tend to sell gear for the next best thing!!!
I did forget to add that Focusrite wanted to make sure I used a Ferrite USB cable and that was heavily shielded from outside crap, recommending me a particular Belkin cable, which really did not mind the $12. USD it cost on Newegg.com whereas in any big box store they wanted little more than twice that!!!
Love learning something new!

[MBTC]

Originally Posted by kittonian

First off a few corrections/updates:

1. The TI2 is USB 2.0 not 1.1

Actually Access touts it as a USB 2.0 compatible device that runs at 12Mbit data transfer rate, and that is the max data rate of USB 1.1 (a.k.a Full Speed mode, as opposed to Hi-Speed mode that USB 2.0 is capable of). This has been well discussed here and elsewhere.

But still, comments well taken and I do understand your point about potentially a software issue and it inexplicably working for a while and then stopping, and you very well may be right. The only thing I could say is that I have seen some USB devices (not synths necessarily) that do not behave well when the computer's power mode changes, for example powering down to a standby mode. It's a long shot but is it possible your system is in some way changing it's power state?

Interesting to me that a Virus dealer is highlighting the problems with software integration here. Perhaps you'll find more appreciation for your focus on this problem than I have. It is a big topic with me because I want to enter Virus ownership again but I keep waiting for a big announcement at NAMM to make a decision.

[Timo]

Originally Posted by MBTC

Actually Access touts it as a USB 2.0 compatible device that runs at 12Mbit data transfer rate, and that is the max data rate of USB 1.1 (a.k.a Full Speed mode, as opposed to Hi-Speed mode that USB 2.0 is capable of).

It's certainly confusing isn't it. Given that USB 2.0 is mainly available in two different chipsets - Full Speed (12Mbps) and High Speed (>480Mbps) - and that a USB 2.0 device with a Full Speed chipset cannot use the High Speed standard (due to requiring a different chipset), what in fact is the difference between USB 1.1 Full Speed and USB 2.0 Full Speed?

Both state they use the same bandwidth of 12Mbps and other similar specs. I wonder if the 2.0 standard added any additional back-end enhancements over 1.1 - such as hardware improvements, the way the data is handled, or error-correction or similar. I understand USB 1.1 fixed many problems that were present in the earlier 1.0.

As a layman, given that Access allow for 3 stereo audio outputs (6 mono outputs) at 16-bit 44.1KHz to be sent over USB...

44100 (sample rate) x 16 (bit depth) x 6 (discrete audio [mono] channels) = requires a bandwidth of 4,233,600 bits/second.

Tidying up, that's 4,233,600 / 1024 / 1024 = 4.0 Mbit/second.

I don't pretend to know much about how USB handles data, whether it is possible to use all the stated bandwidth available (12Mbps in the VirusTI case), but 4Mbits/s is well within the 12Mbit/s Full Speed standard of 1.1 and USB 2.0. In fact it still leaves 8Mbit/s available for Virus Control, MIDI bandwidth, error correction and anything else. On paper, at least, 12Mbps looks like it should be more than enough for the TI's current feature set.

If you started requiring multi-channel 96KHz @ 24-bit, that's a different kettle of fish, new hardware is required (USB 2.0 High Speed or USB 3). Virus TI mk3 material.