Q-SYS Corner

[Steve Guttag]

It would appear that the time away from the office at QSC has benefitted us with some pretty good blog posts:

Barry Farrell discusses DPA-Q amplifiers: https://blogs.qsc.com/cinema/2020/04/23/an-inside-look-at-dpa-q
Jay Wyatt presents some Non-Sync options in Q-SYS: https://blogs.qsc.com/cinema/2020/04...-your-nonsync/

A bit earlier, Rod Archer discussed the Q-SYS platform: https://blogs.qsc.com/cinema/2020/01...ema-processor/

There are also various webinars that QSC has been conducting on the Q-SYS platform (mostly with an eye towards A/V but most of that still applies to Cinema though most don't have to contend with VTC in cinemas!

[Elia Orselli]

The only thing missing is a second level online training

[Steve Guttag]

Actually...they have Control 201 now on-line. The problem is, both sessions filled up in like 30-minutes. In truth, I don't have the time, at the moment, to wrap my head around LUA. I'm busy on 3 active installations and using my home time for driver creation relating to them and getting those designs ready for deployment.

I have a command button component ready for a Sony UBP-X1100ES Blu-ray (I may develop it into a 2-way but, for now, just 1-way command buttons), I'm wrapping up my Extron DXP 42 HD 4K Plus component. That one is 2-way and has signal and HDCP status on the inputs/outputs and can accommodate password protection. Next on the list is an Extron component to control (2-way) XTP T 202 UWP 4K. Thankfully, the Block Editor is allowing me to keep moving forward.

Note, there are two good Facebook Groups on Q-SYS where you'll find many active users (some in cinema, but mostly A/V) as well as actual QSC employees from the Q-SYS group. Even the likes of Jay Wyatt show up there too.

[Steve Guttag]

Q-SYS Designer 8.3.1 has now officially hit the streets. For a full list of 8.3.1 features/resolved issues visit this link:

https://q-syshelp.qsc.com/q-sys_8.3/#Release_Notes.htm

Of note (because they don't come out and say it directly in the notes), the cinema version of the CORE110c does NOT incorporate software Dante. Furthermore, at this time, only the CORE110f ("Systems" aka A/V industry) is the only CORE that supports software Dante.

[Leo Enticknap]

Can anyone explain why, whenever I try to download a new version of the designer package, I fill out the online form with my details, get a screen promising me that I will receive an email link, and then it never arrives? I've checked my junk folder, tried from three different email accounts, and double-checked with our IT guy that the email wasn't being caught in a spam/malware filter upstream from our Exchange server, all with no luck. I'm having to email a contact at QSC every time a new version comes out to ask for a download link, and he must be finding this a bit annoying by now.

[Steve Guttag]

I don't know what to tell you. However, that is definitely a QSC question that I'd take up directly with them.

[Steve Guttag]

I've been working on a project and decided to formalize a surround delay calculator for Q-SYS. It follows the Dolby CP650/CP750 calculator rather than the old chart so it should result in delay times consistent with what has been in use for a couple of decades now.


Screen Shot 2020-05-24 at 6.41.05 PM.png

It follows the Dolby CP650/CP750 delay calculators. It does not require any scripting licenses to use (uses just logic blocks for calculations). We'll see if the user component attaches (my first time at this).

SurroundDelayCalculator200524.zip

[Steve Guttag]

Another user component some might find useful is my "logic fader." It does the 0-10 to dB conversion (follows the Dolby fader law) but uses only logic components. No scripting license is required.

Screen Shot 2020-05-25 at 1.40.48 PM.png

CinemaLogicFader200428.zip

[Marco Giustini]

Thanks Steve!

[Steve Guttag]

Not a problem. At present, the delay calculator only uses moon-landing approved "imperial" measurements . Some day I might add metric...but I wouldn't hold my breath! If god didn't want us using feet, he wouldn't have made the speed of sound so close to 1-foot to 1ms!

[Sean McKinnon]

Nice Job Steve!

[Steve Guttag]

Stay tuned...the delay calculator is going to be revised for Pro Logic delays. When I checked it, it tracks within a certain range...but it does drift as you move out of that range so there is a piece of the calculation that I'm missing. I originally used a simple scaling factor on the theatre length but I now see that it is a bit more sophisticated in how they are compensating the delay based not only on the straight up length and width but also the length/width ratio to some degree.

[Steve Guttag]

As noted, I've made corrections to the Surround Delay Calculator (thanks to some people that gave me a bit of help on that). This version pretty much precisely tracks the CP650/CP750 delay. Depending on how much one's room deviated from a "normal" shaped room, my earlier attempt would deviate a bit. In fact, the screenshot below, rounded to whole numbers yields the same results. The proper calculation has a bit more nuance to it than a simple scaling factor.

Screen Shot 2020-05-29 at 5.05.38 PM.png

SurroundDelayCalculator200529.zip

[Steve Guttag]

So what switches are everyone using for Q-SYS? Those of you using Q-SYS for audio only or audio and control (no video or Dante) are you implementing IGMP querying and snooping? And for those that are using one core per screen, how are you handling IGMP arbitration (presuming you have enabled a multicast scheme)?

I guess, along the same lines, those of you that have one core per screen (or perhaps just have broken up a complex so more than one core to handle the complex) have you implemented any form of QLAN streaming? If so, are you aware that if the core elected Grand Master, by virtue of a lower MAC address, if you haven't manually selected it, if that core is rebooted, all of the other cores lose the PTP clock until a new GM is elected so you could/will have sound drops on other theatres and not even realize you've set yourself up for that.

To answer my own questions:

• At present, I use TP-Link Jetstream series for my audio/control-only systems. These include the T1500G-10MPS and the T1600G-28PS. They do have PoE+ so peripherals like touchscreens are covered (and on every port). They now support both IGMP snooping and querying though they don't, that I've found, support IGMP Querying arbitration (what if two switches both are set to query? Only one should so an arbitration system would ensure only one is doing the querying). Thus far, they have been rock solid with no reported hiccups. In fact, I've yet to hear anyone complain about the TP-LINK (the lines mentioned) switches in QSYS.
  
  Thus far, I have not had multiple independent cores within a complex sharing audio on the QLAN so there isn't a situation where multiple querying switches has been an issue. I do ALWAYS run with a back up network. As such, I would feel comfortable still using a single larger switch at the "top of the tree" to handle IGMP queries since if it failed, QLAN-B would remain.
  
  The other switches I have used, and it was in a mixed discipline environment, was QSC's pre-configured DELL NS switches. https://www.qsc.com/cinema/products/...work-switches/. An advantage here is that everything "QSYS" has been figured out on them and pre-loaded before you get them. You just have to change the IPs to your site's needs. Note they ship with the same IPs per model but different IP for different models. Also, in the event of a change in the QSYS environment, it would be up to QSC to make available the necessary firmware/configuration change. All support for these switches come from QSC, not Dell. The ones I installed when in as painless as it sounds. Just configure the IPs and and plug in...they just worked. Please note, they are, on average about 5X the cost of the likes of a TP-Link or D-Link type switch so in a bigger plex, that could add up VERY fast.
  
  I have not tried but another make/model I see getting some traction are Cisco's SG-350 series. They price between TP-Link and QSC (closer to TP-Link) and do add IGMP arbitration so it is something to consider.
• At this time, my installations have been singles (one CORE110c or CORE510c, depending on the needs), ATMOS (separate CORE for that screen(s)) and we have an active project with one CORE510c (with a redundant CORE510c) on 9 screens so the IGMP arbitration isn't something that has come up. Even on the larger plex, it is just 2-hops (24-port switch connects to each screen with its own 8 port).

[Sean McKinnon]

I have been using primarily Luminex Gigacore Poe+ switches which are very pricey but require zero labor to configure. They are purpose built A/V switches that are pre-configured perfectly (in my experience) to work properly with Q-Lan audio and video and Dante out of the box. Creating VLan's is as easy as assigning a color to a certain port. They also support redundant inter switch links and fiber through SFP's and back up power supplies.

My cheapo Q-Sys switch has been the D-Link DGS 1210-P which works well but takes a little more configuration.

I have also used the Q-Sys Dell switches but my preference is the Luminex.

I had one project where someone else spec'd two different Netgear switches (sorry don't have the model #'s handy) both from the old "approved" list. One was located in a projection booth the other in an amplifier rack on the stage. The one on the stage never worked right. It randomly dropped packets which caused audio dropouts. You would lose for example left high for a few seconds then center low for a few seconds. I spent days with the Q-Sys setup guide for that switch and on the phone and screen share with QSC and Netgear but could NEVER get it to work reliably. We swapped it for a luminex switch and it instantly resolved the problem. Because of this experience I have pretty much sworn off netgear switches.