Q-SYS Corner

[Steve Guttag]

Here are some Q-SYS ideas I have over in their Communities section. Please vote on them, if you too would like to see those features added.
Allow the DCIO to be upgraded to the DCIO-H in the field:
https://developers.qsc.com/s/idea/087TO00000214I9YAI/detail
Add Dolby TrueHD to the supported formats (so one doesn't need work-arounds):
https://developers.qsc.com/s/idea/0874X00000158yFQAQ/detail
Have a QIO-HDMI processor as a stand-alone HDMI, S/PDIF, and analog stereo sound decoder.
https://developers.qsc.com/s/idea/087TO000000y6k5YAA/detail
Offer extended warranties. Who hasn't had a Core or Amp die on them? Being able to sell the equipment with the confidence of support for out to 10-years would be a big plus:
https://developers.qsc.com/s/idea/0874X00000158ytQAA/detail
The ability to name pins on Containers.
https://developers.qsc.com/s/idea/0874X00000158pSQAQ/detail
Sticky Injector. Who hasn't been frustrated by an injector flying back to its parking space because you clicked on the wrong area?
https://developers.qsc.com/s/idea/0874X000000ThlfQAC/detail
More and more devices are using WSDL/Soap and HTML for control rather than traditional ASCII commands, It would be great if the Block Controller could add these to its capabilities
https://developers.qsc.com/s/idea/0874X000000iwhCQAQ/detail
It's a personal one...but I'd love for an Eprad eCNA plugin.
https://developers.qsc.com/s/idea/0874X000001598zQAA/detail
A Dataport I/O box. Who doesn't have DCA amplifiers in the their world? There are over 500,000 DCA amplifiers out there...having a Dataport I/O box with 6 dataport connectors would allow Q-SYS to move into existing systems without changing amplifiers or their wiring. With 6 such dataports, you cover most 5.1/7.1 sound systems up to bi-amped screen channels. With two such boxes, you cover all of the way up to 7.1 quad amped.
https://developers.qsc.com/s/idea/0874X00000158z3QAA/detail
Barco ICMP (Alchemy) server plugin (I've asked for a GDC one too but there seems to be friction there).
https://developers.qsc.com/s/idea/087TO000001emYPYAY/detail
I'd like the ability to create versions of scripts/block controller scripts so that they can have the benefit of when one updates the user component, one can update a design without the need to rip-out/replace all instances of the user component.
https://developers.qsc.com/s/idea/087TO0000025swHYAQ/detail

[Steve Guttag]

Q-SYS For Cinema
Blog-4 Hardware–Part-2, DCIO(-H)
_11/10/24
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Introduction

In the previous blogs, I have:

1. Gone over the concept of Q-SYS within the cinema environment.
2. Introduced the software (QDS).
3. How to choose the right Core for your project.

In this part, I’m going to talk about getting the cinema sound (and possibly control) into the system and some cinema-specific sound/control out of the system. The one piece of Q-SYS hardware that is dedicated to cinemas is the DCIO/DCIO-H (Digital Cinema Input Output). Nearly all cinema systems should have a DCIO or DCIO-H in the design. Possible exceptions would be those with a dedicated cinema processor where the sound is getting into Q-SYS by analog or other means. In our systems, we even use the DCIO-H on our immersive systems (e.g. Dolby Atmos^®).
In this blog, I also want to start you on the path of thinking like a Q-SYS designer instead of a traditional cinema processor designer.

Disclosure

I do not, in any way, work for QSC/Q-SYS. These thoughts are my own based on my own interactions with the product(s) and implementing Q-SYS within actual cinema environments. I do work for a dealer that has sold QSC products since the 1980s, including Q-SYS and its predecessors. For the purposes of this blog, I represent only myself and not my employer(s) or any other company.

DCIO or DCIO-H?

The only difference between the DCIO and the DCIO-H is the inclusion of an HDMI audio decoder on the DCIO-H. You must choose which version you want when designing/purchasing the system because there is no provision for upgrading a DCIO to a DCIO-H later (unfortunately).
The vast majority of our existing systems (possibly all) have been with the DCIO-H but we do tend to cater to cinemas that run alternative content where the HDMI decoding has come in handy and essential.

The Front Panel
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The front panel is the same on the DCIO and DCIO-H except the silk screen.

OLED Display

It has an OLED display that can provide design information as well as IP address information. It also functions as a display for signal presence and volume level (in dB).
The “NEXT” button works in conjunction with the display as does the ID (Identification) which is part of all Q-SYS native components to help identify which component you are talking to in the design or in person (when activated, it will signify in most every interaction with the component).

Level and Mute

Here is where I will start (hopefully) changing your mind on how to think of things within Q-SYS. The Level control is just a rotary-encoder control that has a range of -100 to (+)20. It isn’t connected to anything in the design. You have to do that and in any manner that suits your design. You might want it to be your main house fader. Or maybe you want it to be the local booth monitor fader. It’s your choice.
To drive the point home even further, you don’t have to use it as a volume control at all. You could have it control a dimmer or change colors in a lighting system or be part of a phone dialer, if you really wanted.

Key Point: Almost everything within Q-SYS is “General Purpose” and only gets a specific purpose when YOU assign it one.

The Level control is just a control “on-ramp.” YOU decide what it does, within its limitations (it can go between -100 to 20) and what you can turn that information into. For example, you could add a Control Function to its output that adds 100 to everything so then it becomes a 0-120 control.

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Note that it is located within the “GPIO” component for the DCIO. Sure, 99.9% of the time, cinema people will use it as the house fader but your hands are not tied to that. It is a general-purpose knob to be used as you need. For example, all of our systems turn that DCIO level control into a 0.0 – 10 fader (and back to dB again as a feedback loop to the control).
The Mute button follows suit. The Mute button is a general purpose “toggle button” with a state identifier (LED on the front panel). 99.9% of the time, people will use it as the system Mute button but nothing requires you to use it that way. It doesn’t actually mute anything until you connect it up to a mute somewhere in your design.

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[Steve Guttag]

The Rear Panel

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Referring to the image above, you can see that it covers a lot of ground and is quite cinema-specific. I believe we have used most every feature on it. The most conspicuous absence is the omission of some form of S/PDIF input (coax, optical or both). As such, if you need to support a device that uses S/PDIF audio, you’ll need to either convert it to analog stereo and bring it in the Line Inputs or use an external decoder and bring it in elsewhere (see below, Extron SSP 200).
Here is an example of how a Cinema Engineer and a Q-SYS Engineer will size up a Q-SYS device:

Cinema Engineer Analysis of the Rear Panel:
A traditional cinema engineer will look at the rear of the DCIO-H and see it as:

• Mic/Line input (but mostly mic). [*=1]Stereo non-sync on a 3.5mm jack.
• HI/VI outputs. [*=1]Booth Monitor output (both line and speaker level).
• Relay outputs (4) [*=1]AES3 audio inputs from the DCP server (8-pairs/16-channels).
• Automation inputs (6) [*=1]RS232 control (1).
• And, if the DCIO-H, an HDMI decoder with pass-through.
• Network Connections (2).

There is nothing really wrong with that way of looking at it. And that is the way it is labeled. However, it can be unnecessarily limiting. It is best to look at the labels as mere suggestions.

Q-SYS Engineer Analysis of the Rear Panel
Okay, here is how someone that works with Q-SYS equipment will look at the rear panel of the DCIO-H:

• Balanced Mic/line audio input (1).
• Stereo line unbalanced input (1) on 3.5mm jack.
• Balanced line outputs (3).
• Speaker level (10W) output (1).
• Relay outputs (4).
• 8-channel AES3 digital audio inputs (2).
• GPI inputs (6) for contact closure or 3.3V digital.
• RS232 control (1).
• HDMI audio inputs, with passthrough combined with AES3 port 2.
• Network Redundant capable QLAN.

It is very similar. The key difference is that a Q-SYS person will look at EVERYTHING as nothing more than on-ramps and off-ramps into or out of the system. The labels and intended purpose only provide a degree of ease in particular installations. Do you really need both line and speaker level outputs for a booth monitor? Odds are you are only going to use one so the other is available for something else.
You should see just what each port is capable of supporting. For instance, not all GPIO ports are treated equally. In the case of the DCIO series, the GPI (labeled Automation) can be selected within Q-SYS as either a contact closure type input or a level sensing type “digital” input (digital means it is going to sense only high or low levels, not an analog level as would be used with a potentiometer). The relay outputs are just that, relays and not the more delicate “Open Collector” style used on most GPIO systems. So, they could be used to switch dimmers, masking machines and other low-voltage, low-current devices.
Note that it has both QLAN-A and QLAN-B. So, it supports redundant-network systems and it is going to be highly reliable getting things in and out of the system. This is one reason we use the DCIO series even on Atmos^® systems. AES3 is more reliable/doesn’t need a carefully configured network, unlike AES67. So, getting the audio into the system is more reliable and the network-redundancy ensures a high degree of reliability getting it to the speakers. With an AES67 system, you are depending on every $2 cable working and all configurations working optimally. It isn’t that AES67 is unreliable; it is reliable. AES3 and network redundancy is, significantly, more reliable. Which is worse? Shifting back to 7.1 audio or cancelling a show? The DCIO gives your highest profile theatres more options to minimize cancellations.

Another reason to think about all of the inputs/outputs as generic is how it will be represented within QDS’ schematic. If you drag the entire DCIO-H into a schematic, it looks like this:
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Naturally, you’ll want to move things about so everything is located in logical places, with respect to your design. The key takeaway is, nothing is connected up, out of the box. What you do with the inputs/outputs is entirely up to you.

The DCIO-H Components
Status

It is, generally, good practice to provide status from hardware and scripts. That is its way of letting the user know if there are issues. As such, it is often best-practice to expose the status pin and wire it to a status combiner so you can present all of the statuses in a single place.
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In our systems, I normally have one box on the “home” screen (aka dashboard) that will show the result of all of the statuses being monitored.
Digital In (AES3 and HDMI)

This is where your normal DCP audio will enter.


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If you have the DCIO-H, HDMI audio enters here too. Please note, the HDMI audio shares the input with channels 9-16. One has to enable the desired audio on a format-by-format basis. There are good and bad aspects to this.

By sharing the input, it reduces your input channel count by not having to have up to 8 additional inputs. Since cinemas are input intensive, inputs are often the limiting factor in how many screens you can put on a single core.

The down side is you can’t use the HDMI as a discrete input, which could come in handy if you don’t want to have ten DCIO-H systems in a 10-plex but would rather just have three, for instance, to cover the worst-case need of HDMI sources and then route those HDMI sources to the needed theatres for a particular event.

Note, the HDMI decoder supports LPCM, DTS all of the way up to DTS-HD (Master Audio) but Dolby is only supported up to Dolby Digital Plus (no “high-bit rate” audio like Dolby True-HD). This can trip you up as some devices do not behave properly to the EDID that lists those capabilities. Some will refuse to send DTS-HD because of the lack of Dolby True-HD and some will send Dolby True-HD because they see DTS-HD. They shouldn’t but I’ve experienced both scenarios. So, watch out. It would be best if the DCIO-H also supported Dolby True-HD.

It does not support either DTS-X or Dolby Atmos but if you have those systems, odds are, you have a suitable decoder too (Dolby cinema Atmos decoders will decode consumer Atmos as well).

The HDMI audio decoder does feature an “up-mixer” so you can force an audio output that matches your channel configuration from 2-channel sources.

The other area of concern with the DCIO-H is on the video side. It’s EDID will list that it can support 4K but is 1080 native. Sources seeing that will send 1080 rather than 4K. Additionally, putting the DCIO-H in line between the source and the projector means it has to act as a “repeater” in the parlance of HDMI and HDCP. As such, you can open yourself up to HDCP issues if the source doesn’t interpret the “sink” properly, after it has been repeated through the DCIO-H. Test your set up with ALL sources.

The DCIO-H takes care of routing the audio in the order expected by digital cinema (Center and LFE are in their correct places). It also has the metadata for the encoding type as well as active channels for the encoding.
I have never needed to alter the input levels of the DCIO-H; however, I do put a gain control on the HDMI outputs to better balance them with DCPs (they often will be significantly lower).

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[Steve Guttag]

Analog In
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For the most part, you do not need to keep track of your gain structure, except where you encounter analog. The precision/bits within DSP are such that you aren’t going to digitally clip anything, even with heavy EQ. But you must monitor your levels when getting the audio in and out as there are definitely limits to the analog inputs and outputs. Furthermore, there are noise benefits by getting your gain set where it is best.

Key Concept: Analog inputs/outputs will tend to have two gain sections. The Analog gain comes before the Analog-to-digital converters so this is where to get your gain structure correct. The digital gains are no different than if you put a “Gain” component somewhere in your design.

Mic

It is labeled “Mic” but it will work with a mono line source as well. If you are connecting a microphone, this is where you will want to get your gain structure correct. It can accommodate mics needing phantom power and it has a wide gain range to get the microphone up to a nominal level suitable to your needs. Try to set all of the gain that you will need with the Preamp gain rather than adding it later, digitally.

Left/Right

There is just a High and low sensitivity setting rather than a variable level. Like with the Mic preamp, pick the level that best gets you into the range you need for your source. It is a 12dB gain when selected. You can then finish the job with the digital gain levels either right there on the input or elsewhere in your design with Gain controls.

Analog Out
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Again, while they are labeled for typical cinema installations, they are three analog line level outputs with a speaker level output.

Level Controls

By and large, you should adjust your levels in the digital domain to get them into the proper range, if necessary. The Analog controls are after the digital-to-analog converters so, really, they are only going to accommodate some outside device that doesn’t have its own input attenuators.

Speaker Level

The speaker level out is a 10-watt chip amplifier without any real headroom at all. A quirk of the volt meter in the component is that its range is such that you can clip out the amplifier long before it would, otherwise, show a full range. You will likely need to set the gain for the speaker level to match the speaker you are using and to avoid clipping (consider using a compressor and/or limiter components to avoid clipping).
While the amplifier is adequate for typical installations where the person is going to be right in front of the speaker, if your needs are such that the monitor speaker(s) need to get to a decent level, consider using the line level output to another amplifier (or perhaps the SPA-Q line of amps or you might have a channel or two left over from your CX-Q amplifiers).

Relay Mute

The relay mute is really an item of convenience. It mutes all of the analog outputs from a single point, which could be handy for integrating with a fire alarm system or even a system mute button.
Note, it is located in the analog section so it comes after the digital-to-analog converters. So, the meters will still show activity.

GPIO
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As noted, previously, you have a control that goes from -100 to 20, and a mute (toggle) button. Typically, they are your system fader and mute controls as they are connected to the physical buttons on the front of the DCIO.

The relay outputs are “real” dry-contact relays with both Normally Open and Normally closed outputs.

The inputs are opto-isolated and are typically used with external contact closure devices (i.e. switches or relays, like from a fire alarm system). There is a provision to turn them into a “digital level” sensing inputs by changing the properties in the right-hand pane. It terminates into an RJ45 connector where pin 8 is the ground (reference) and 1-6 are the inputs with 7 unterminated.

RS232

The last I/O is the RS232. If you have a device (e.g. Blu-ray player) that can be controlled via RS232, this is the place to connect it up. As will be discussed in a future blog, Command Buttons or Scripting can be used to take advantage of RS232 (and Ethernet) control of 3^rd party devices.

Alternately, you could use the RS232 as a means of an outside device to control Q-SYS in some manner. For instance, if you have an older server, like the Dolby DSS line, the RS232 port might be best way to interface the two.

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[Steve Guttag]

HDMI (and S/PDIF) Revisited

I don’t want to get too far into the details of handling video applications in this blog as it is a subject unto itself. However, as mentioned above, the DCIO-H has some limitations accommodating all that a cinema might encounter. Additionally, you might only have a DCIO and want to add HDMI later. You cannot update (at least at the time of this writing) a DCIO to a DCIO-H.

For 90% (or more) of the situations a typical cinema comes across, the DCIO-H does the job and integrates very well. For more intensive installations, you might want to consider an external HDMI (and S/PDIF) decoder.

S/PDIF to Analog

There are numerous S/PDIF to analog decoders out there for just LPCM audio, resulting in an analog stereo source. This can be brought into the DCIO via the 3.5mm stereo line input and then, if desired/appropriate, use a Matrix Decoder component to get a 4-channel result.

HDMI, AVRs and the Extron SSP 200

There are numerous means of decoding HDMI out there. There are consumer and “prosumer” Audio Visual Receivers (AVRs) and even prosumer type preamplifiers. The drawbacks of using this sort of solution are:

• How much space they take up in the rack (they are, typically, huge).
• The product life-cycles are typically very short.
• They don’t seem to hold up very well.

Extron SSP 200

If you are looking for a commercial grade (and controllable) HDMI and S/PDIF solution, the Extron SSP 200 may be your answer. Be prepared, it isn’t cheap and will cost more than the upcharge of the DCIO-H over the DCIO but it does remove quite a few of the limitations of the DCIO-H.

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It has S/PDIF in both coax (1), optical (2) (with Dolby and DTS decoding). It also can decode analog stereo.

For HDMI, it supports DTS and Dolby through their immersive formats (DTS-X^® and Dolby Atmos^®). Now, to use something like this, you will need sufficient analog inputs. And, if you plan on going beyond 7.1.2, you will have the added expense of adding an Extron DSP based processor too (that allows you to convert its “DMP EXP” output into Dante or AES67).

However, if all you are doing is 7.1 out, it can even provide a stereo mix-down for previewing.

I think, for most use-cases, in cinemas, its analog outputs will be sufficient, considering that most cinemas will have plenty of leftover analog inputs via the CX-Q amplifiers.

Conclusions

The DCIO/DCIO-H is an essential piece to any cinema implementation of Q-SYS. While the DCIO-H’s HDMI decoding does have some limitations, it does cover a very large percentage of the use-cases that might be asked of it. I can’t think of any cinema installation that wouldn’t benefit from having one in the design since it covers so much of what typical (and special venues) need.
©2024 by Steve Guttag

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[Steve Guttag]

If any of you were using Q-SYS before QDS 8.0, you may recall that they had an algorithm that one could use some physical parameters combined with rated pink noise power to calculate the limiter's parameters. In QDS 8 they opted to just reveal the limiter parameters and let you put them in directly. Now, if a manufacturer has their own parameters listed, those should be used as the manufacturer should know specific qualities of their product. However, if those are not provided and you need to start somewhere, then Q-SYS's developed methods is a good starting point and one that has worked for me.

Attached is my Excel spreadsheet that encompasses Q-SYS' original formula.

CustomSpeakerPower231027.xlsx.zip

There are other companies that have their own formulas too. Notably LEA (known for their amplifiers) has an on-line calculator:

https://leaprofessional.com/loudspea...er-calculator/

As well as the calculator available in Excel spreadsheet form:

https://leaprofessional.com/download...er-calculator/

The Q-SYS method is more conservative, in my opinion but I've found that I haven't had any speaker damage and I haven't found it intruding into any movie playback.

[Steve Guttag]

QDS 9.12.1 has been released. Other than the Control Links being fixed after a redundant-core fallover, I don't see this one affecting many/any cinemas:

Version 9.12.1 was released November 18, 2024. It corrects an issue where network processing was incorrectly allocated across the appropriate CPU cores when a Design contained CAT 2 processing (Acoustic Echo Cancelers (AEC) and Notch Feedback Controllers (NFC)). The issue affected Designs containing these components when deployed to Core 5200, 6000 CXR, 1100, or 3100. The observable symptoms after deployment of such a Design to one of these Cores may include missing Peripherals, Q-LAN streaming errors between Core and Peripherals, and networking or connection errors within Streaming I/O components.

Note: For a complete list of new product support, updates, and resolved issues in version 9.12.1, see v9.12.0.

Resolved Known Issues

• Platform: Resolved an issue that prevented Control Links from reconnecting after a Core failover event in systems utilizing redundant Cores.