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
Picture1.jpg

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.

Picture3.png

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.

[End of Page-1 Blog 4]

[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:
Picture5.png
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.
Picture6.png



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.


Picture7.png
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).

[End of Page-2 Blog-4]

[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.

[End of Page-3 Blog-4]

[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

[End of Page-4, End of Blog-4]

[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.

[Steve Guttag]

Q-SYS For Cinema
Blog-5 Hardware–Part-3, Amps and Speaker Voicing Picture1.png



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. Covered how to choose the right Core for your project.
4. Discussed the DCIO/DCIO-H, which gets the sound into and some cinema-specific sound out of the Core.

In this blog, I will discuss getting the sound out of the Core and into the theatre by way of amplifiers and speakers. At first, that doesn’t sound any different than we’ve been doing with conventional sound systems. However, with Q-SYS there are some additional configurations and features to consider.

• What sort of signal are you using to feed your amplifiers?
  • Q-LAN (e.g. CX-Q amplifiers).
  • AES67.
  • Dante.
  • Analog.
• What sorts of protection do you wish to apply to your speakers?
  • Limiters.
  • Compressors.
  • Impedance range.
• Voicing.
  • For most Q-SYS speakers, Q-SYS has their Intrinsic Correction™ that encompasses both voicing and speaker protections.
  • Do you have voicing parameters supplied by the speaker manufacturer?
  • Do you have your own custom voicing and speaker protection parameters that you need to load or configure?

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.

Choosing Your Output Type

Q-SYS can work with traditional analog amplifiers (you just need to have enough analog outputs in your design and hardware), AES67, Dante, and, of course, Q-LAN. For all examples in this section, I will use the same 4-way speaker, (QSC SC-424) wired up as a 3-way with 2-channels bridged for the Low-Frequency, one channel on the midrange, and one channel to the high and very high frequency. I will use the speaker’s passive crossover to split the high and very high frequencies.

Analog Amplifiers

If you are going to use traditional analog amplifiers, that do not have QSC Dataports, then you’ll need to ensure your system has enough analog outputs to feed those amplifiers. These outputs could be on the Core itself (e.g. a Core 110f-V2 can have up to 16 analog outputs or it can be used with other Cores, in peripheral mode, too). Or you can use a peripheral such as the QIO-L4o (Note, the QIO series of products are single-network only but they can be daisy chained so you could get up to 16 analog outputs in 1U of rack space by putting 4 of them on one shelf).
You will need to wire these analog outputs up as you would any other sound processor to the analog amplifier, including any bridging/parallel configurations.
You can use crossover components in your design or you can have “inline” speaker components reference a voicing component to handle the crossover (as well as voicing).
In this example, the SC-424’s speaker component was set to use inline processing in the right-hand-pain properties. This only provides for crossover and voicing. No speaker protection (limiting) can be provided since the output of the amplifier is unknown.

Picture2.png Picture3.png

Key Point: The speaker component normally references a voicing component for both voicing and crossover. For Q-SYS native speakers with Intrinsic Correction™, the speaker component carries all of the needed information within the component itself. In all of these examples, the crossover and speaker protection are completely defined in the speaker components. It will feel strange, at first, to “wire,” within QDS, the same signal to all of the amplifier inputs for a channel but that is how it’s done.

AES67 and Dante Amplifiers

AES67 and Dante amplifiers connect up and have the same relationship to voicing/crossovers as analog amplifiers. It should be noted that some analog amplifiers and most AES67 and Dante amplifiers have some form of DSP in them to also offer crossover and voicing options.

Picture4.png

If you are going to use the amplifier’s DSP to handle voicing, then you can connect the signal directly to the outputs (and likely just one signal per channel and let the amplifier distribute it appropriately).
Some of these AES67 and Dante amplifier companies, notably LEA and Powersoft, have made plugins for Q-SYS to make the integration of these amplifiers easier. It is worth looking into the various models as many have GPIO as well as analog inputs that could be routable inputs, just like Q-SYS native amplifiers. If you use a plugin (any), then your system must have the appropriate Scripting License for your Core.

Note, AES67 transmitters/receivers are “free.” Just ensure that you check to see what the limitations are of your Core for how many channels/streams it will support.
Dante transmitters/receivers are licensed. See the section “Dante Considerations”

Q-SYS (CX-Q) and Dataport Amplifiers (DCA)

The popular QSC DCA amplifiers can be wired up conventionally as analog amplifiers. However, it is still possible to take advantage of their Dataports from within Q-SYS. While the Core 510i remains in production (or via used I/O frames since the I/O frames have been discontinued) and using a sufficient number of CODP4 cards, one can use a DCA amplifier with most of the benefits of a Q-SYS native amplifier (CX-Q). In addition to the fast-easy connectivity that the Dataport cables bring, the Dataport modules also have internal DSP processing to handle voicing and speaker protection.

Picture5.png

Key Point: There are non-QSC amplifiers with Dataport (HD15) connectors. Those are not full Dataport connectors and only have the inputs as well as monitoring outputs. They lack the “Data” part of the Dataport to work with the Q-SYS module to provide the full amplifier feedback. (The QSC ISA amplifiers use a reduced function Dataport so that they could be used with the XC-3 and SF-3 crossovers/subwoofer filter, they are not suitable for use with Dataport cards).

[Page 1 of 4, Blog 5]

[Steve Guttag]

By far, the easiest implementation is to use Q-SYS native amplifiers. Currently, they are from the CX-Q line (there are also a line of utility amplifiers, the SPA-Q, which could be used for booth monitors or auxiliary/party/VIP rooms and, previously there were DPA-Q amplifiers).
CX-Q amplifiers support network redundancy and the current versions all have analog mic/line inputs as well as some form of GPIO control. SPA-Q amplifiers have Flex audio, and some GPIO. Note, older amplifiers that have an “n” in their name omit the analog inputs (e.g. DPA-8K8Qn).
With the CX-Q amplifiers (or Dataport amplifiers), you get to off-load the DSP needed to voice the speaker to the amplifier rather than covering that overhead within the Core itself (everything is still configured within QDS and feels like you are implementing it within the Core).

Dante Considerations

Q-SYS supports Dante. All new Cores come with 8x8 channels of software Dante and one may purchase larger Dante licenses to increase that amount, up to the limits of the Core. Additionally, the Core 510i can support up to two Dante bridging cards that support up to 64x64 channels each (no license is required since it is included with the card). Dante does support network redundancy!
Like with all Dante audio, Dante Controller (obtained from Audinate) is used to configure the signals between the Core and the amplifiers or other Dante peripherals (note most devices that support both Dante and AES67, will tend to use Dante Controller to configure the device for AES67).

Dante Networking Considerations

Dante uses different network DSCP values than AES67/Q-LAN. If you are using software Dante, you will need to change your DSCP values within QDS Design Properties to “Audinate.”

Picture6.png

If you are implementing a Dolby Atmos^® system, this could have some implications since Dolby Atmos^® uses AES67, which uses different QoS DSCP values.

Picture7.png

Depending on your switch’s performance, you might “get away” with not paying attention to QoS but QoS is there to ensure that critical packets, like the PTP clock and Audio don’t have to wait for other network traffic. Another consideration is that Dolby Atmos processors (IMS3000 and CP950A) want to be the PTP Grand Master clock and will be unreliable if they are not. This is doable with an AES67 system. Furthermore, Q-SYS has Dolby Atmos^® specific receivers (customized AES67 receivers).
I have not tried to combine Dolby Atmos^® with a software-Dante implementation. In those cases, I’ve used the Core 510i with a Dante Bridge card, which solves the issue entirely. Dante runs on its own network and Q-LAN (with AES67) run on their own network, with each optimized.

Amplifier Location

Something all of the networked amplifiers bring to the table is the ability to locate the amplifier(s) close to their speakers. This will significantly reduce the cost of using the large speaker wires going to the screen and subwoofer channels.
This will likely apply more to new-builds because power (100-240VAC) will be needed behind the screen or wherever you wish to locate the amplifiers.
Aside from the power, all that is needed for connectivity is 1-2 CAT5e/CAT6 cables. You can also locate a network switch with the amplifiers to reduce that long cable run to just 1-2 cables total. Then you can run relatively short speaker cables.
Unlike with traditional systems, you get full monitoring of the amplifier with Q-SYS, including amplifiers that have suitable plugins. If you are using Q-SYS amplifiers, you can even monitor the amplifier’s audio OUTPUT, as we have traditionally done. In fact, Q-SYS is bound to do a better job of monitoring its amplifiers since it can be proactive rather than depending on the staff to visually notice, or the patrons to hear the problem.
You can split the locations too. Locating the surround amplifier(s) in the booth has the advantage that the rear surrounds are just on the other side of the booth wall as well as the side-surrounds also come very close to the booth wall.
There are other benefits to locating (some of) the amplifiers behind the screen. Each amplifier has analog inputs, which could be quite handy for things like microphones. You might find that if you are using wireless microphones, locating the receivers behind the screen puts them closer to where you are using the mics, including having adjacent theatres share one or more wireless receivers. Furthermore, you have the option of going wired by putting in a suitable wall plate.
Each amplifier also has a GPIO terminal so you could use that to control things (including masking) or provided a wired interface for lighting, when renting out the space. Each CX-Q amplifier has one dry-contact relay on its GPIO terminal.
Remember, with Q-SYS, everything is an on or off ramp into the ecosystem. An input or GPIO is not for that specific amplifier/device.
Considerations for locating the amplifiers behind the screen include:

• Sufficient AC power. Don’t be afraid to run your amplifiers on 208VAC (USA commercial power). If you have a high-power system, you will need enough power coming in to support that power output. You may find that running at 208VAC can be more efficient/better means of meeting the power needs.
• Cable path/conduit for the Q-LANs cables (in lieu of a speaker cable path from the booth).
• Sufficiently clean to allow the amplifiers to cool themselves. It’s behind the screen, so it isn’t going to be spotless but the amps can’t get clogged up with candy wrappers. Consider using filters and cleaning/changing them on a regular basis and/or building a small closet for them.
• The ability to isolate the fan noise of the amplifiers (CX-Q amplifiers have significant fan noise so you would need a closet, hush box/rack or otherwise mitigate their noise while allowing for cooling).

Voicing and Speaker Protection

A Q-SYS video that discusses the voicing and speaker protection (as well as many of the topics shown above) can be found here:
Q-SYS training video on Voicing and Speaker Protection
Voicing

When I refer to voicing, I’m referring to the tuning that encompasses the crossover(s), if any, as well as any tuning that is speaker specific. This is different than room equalization, which is applied to mate the speaker(s) to the room and its environment.

Ideally, the manufacturer of the speaker will have voicing data available for you to enter into a Custom Voicing component. In the case of Q-SYS speakers, using the speaker from within the Q-SYS inventory will, automatically, apply Q-SYS’ Intrinsic Correction™. Here is a link to a pdf on Intrinsic Correction™:

Intrinsic Correction PDF

Just because a manufacture has either published voicing data or you are able to read what they are applying to another make of DSP/Amplifier does not mean that it will perfectly apply to Q-SYS’ DSP. All filters are not created equal.

Another reality of speaker voicing is that they are often done to achieve a mostly-flat response in an anechoic chamber or another, similar, non-reflective environment. The problem is, that is not representative of a cinema. I consider the manufacturer’s voicing parameters to be a starting point. If you find that after entering them in that you will have to EQ any/all of them out, then it is better to not EQ an EQ. This is true of Intrinsic Correction™ (which is more complex than mere PEQ; they use a combination of FIR and IIR filters) as well. I have definitely found where I was having to back out a response that was caused by the Intrinsic Correction™ filters.
It is beyond the scope of this blog to really get into voicing techniques. Suffice to say, a good voicing is one that seems to work in most/all cinemas (with reasonable acoustics) without having to EQ the same frequencies in every theatre.

[Page 2 of 4, Blog 5]

[Steve Guttag]

Custom Voicing Block

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The voicing block can have up to 9-filters per band. They can be of several filter types and it is also possible to ingest a set of FIR filters. Just know, the voicing block normally uses the amplifier’s DSP in an CX-Q installation, so your FIR filter capacity is very limited (just 200 taps on an 8-channel amp and 1024 taps on a 4-channel amp).
Setting the High-Pass and Low-Pass filters for each band forms the crossover. Most of the usual filter types and slopes are available. Delays for time alignment are also included.
One of the great things about Q-SYS voicing over traditional amplifier DSP (or even other DSP platforms) is that one need only have ONE instance of the Custom Voicing component and refer all of the speakers to it. You don’t need (or want) one for each copy of the speaker (one voicing works for Left, Center and Right speakers).

Generic Speaker Block

Picture9.png

The Generic Speaker Block is where you put in the specific parameters for your speaker (number of speaker sections (ways) as well as power handling). There are multiple means of getting this data. Ideally, the speaker manufacturer specifies their desired limiter parameters. These should always be used over other methods.

Q-SYS, in QDS versions below 8 had their own formula based on published power handling, combined with voice coil diameter as well as if it is a compression driver or a conventional cone driver. While they no longer use that and, instead, let the user put in the parameters directly, I have made a spreadsheet that utilizes the original formulas. I have posted it in the Facebook group “QSC Q-SYS Programming Super Group” in the Files section.

Facebook Group location of Excel File

And on Film-Tech:
Film-Tech location of the Excel File

There are other companies, like LEA, that have their own calculators that also take a manufacturer’s published data and gets you a good starting point.

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

Note, if you find that you are activating the limiter during normal playback, you probably should have specified the speakers/amps a bit better such that they properly fit the room’s power/SPL needs.

I have found that the Q-SYS original method is a bit more conservative for the RMS parameters but hasn’t intruded into any system where I’ve used it. The LEA calculator will calculate Peak Attack and Release times. LEA’s calculator is a little more conservative on the Peak Voltage.

For example, let’s use the JBL 2446H (8Ω), as used in the JBL 4675C speaker system. Historically, screen channel 2-way speakers set the crossover at 500Hz (keeps it out of the dialog region).

Picture10.png

Using a traditional Q-SYS limiter, it would calculate to this:

Picture11.png

Using the LEA calculator, it would be this:

Picture12.png

I think both methods have merit and I haven’t run into problems. Again, ideally, the manufacturer has done specific testing on their components to determine just what protections that they really need.

CX-Q Amps and Sizing

Since this is a blog on Q-SYS for Cinema and, likely, the most prevalent amplifier will be from Q-SYS, it is worth looking at how to best size/utilize the CX-Q (and the former DPA-Q) amplifiers since they are notably different than conventional analog amplifiers, like the DCA amps.

They are Class-D amplifiers and while this blog will not go into the various power amplifier topologies, you should be aware that the power relationship between the load (speakers) is not the same as with traditional, linear amplifiers. For instance, the power does not double (or nearly double) as the impedance is cut in half. In fact, you’ll likely find that the power output of Class-D amplifiers is the same for both 8Ω and 4Ω and less power for 2Ω and 16Ω. You really need to pay attention to what each specific amplifier’s output capabilities are for the loads you intend to connect to it.

In the case of the CX-Q amplifiers, think of the 8-channel amplifiers as two 4-channel amplifiers in one case. How the amplifier shares power in an 8-channel amplifier is split along two sets of 4-channels.
Max Power versus Continuous Power

Another characteristic of the CX-Q amplifiers is that they have very larger power rails. At present, they are approximately ±148V on all of their models, regardless of power rating. This is vastly different than traditional amplifiers where the power rails are sized based on total power output. What these large power rails allow for is a very large “Max Power” compared to their Continuous Power. So, for instance, on a CX-Q 2K4 (the smallest of the CX-Q line), the 8Ω Continuous Power is 400-Watts. However, its Max Power is 700-Watts. And each of the four channels have that rating! This puts that “small” amplifier somewhere between the size of two DCA 1222 and the DCA 3422, depending on how you hook it up and what your loads are.

Max Power takes advantage of the nature of music and speech in that they are not continuous tones. Instead, they have a rather low RMS power usage but there are very brief bursts (peaks) that may be significantly higher than their nominal level. In a conventional amplifier, if you go above its power rating, even briefly, it clips. The power rails are not high enough to deliver the signal. On the CX-Q amplifier, it does not have this issue.

For cinema applications, on all channels except the subwoofer, you can safely use the Max Power rating when sizing the amplifiers. Once you convince yourself of this, you’ll find that the smaller, CX-Q 2K4 (4-channel) and the CX-Q 4K8 (8-channel) cover a LOT of ground.

The subwoofer channel, on the other hand, can have sustained high-level signals. As such, I would recommend sizing the amplifier(s) for subwoofers based on Continuous Power.

Here is a link to a slightly dated video (uses DPA amplifiers and of the 1^st generation). The principles still apply. And you are free to do your own experiments.

DCA versus DPA-Q amplifiers.

Bridging versus Parallel Output

With conventional amplifiers, rarely are the inputs/outputs configured in parallel for more current (some amplifiers allow for this to attain very low impedances like 1Ω). With Class-D and, in particular, the CX-Q series, the use of parallel output and bridged output are means to get the best power transfer based on the load. In general, if you are presenting a lower impedance (like 4Ω and less) the best mode is likely parallel power. For higher impedances (8Ω and above), bridging will result in more power. The CX-Q provide for using 1, 2, 3 or even all 4 channels to get the power you need on a single output. They are VERY flexible that way.

Along with bridging and parallel output, you can drive Hi-Z (e.g. 70V) by configuring the output as such. Therefore, you could drive lobby speakers from the same amplifier that you may be using for the cinema audio, if you have a spare amplifier channel.

Here is a chart that shows the current amplifiers and what their power ratings are. The values in bold will indicate the highest power output for that impedance for both Max and Continuous Power using the same number of amplifier channels.

So, if you have a 4Ω subwoofer system and you want to see what is highest continuous power you can get from a CX-Q 4K4 using 2-channels, it is 1250-watts and it can be obtained from parallel mode. If you were to have used a more traditional bridged mode, you would only obtain 1150-watts. Mind you, that is only a 0.4dB difference. But it doesn’t cost you anything to configure it more efficiently.

Let’s say you have a 4-way Center speaker and a high-powered double-18 subwoofer (with two 8Ω drivers) and are using the CX-Q 8K8. You could let half of that amplifier run the Center channel and then, on the other half, wire each driver of the subwoofer to a bridged pair of channels for 1200-watts per driver continuous (3000-watts peak) for 2400-watts to the subwoofer system continuous or 6000-watts peak! Again, VERY flexible.

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[Page 3 of 4, Blog 5]

[Steve Guttag]

If you would like a more detailed explanation of QSC’s “FAST” (Flexible Amplifier Summing Technology) and the relationship of bridged versus parallel outputs as used in CX-Q (and related) amplifiers, here is a paper on the subject (it is a really good read if you are into amplifier technology):

QSC FAST Amplifier PDF

CX-Q Amplifier Considerations

As has been shown above, the CX-Q line of amplifiers have a very wide power range, if you take advantage of their FAST technology (from 200-watts to 8000-watts). They also have, potentially, convenient analog inputs as well as GPIO interfaces. However, all is not ideal for all situations. Here are some things to consider:

• [*=1]They only come in 4 and 8 channel versions. In cinema, we often need an odd number of channels due to the Center speaker so some consideration may need to be given to getting the right quantity and size to accommodate the varying power needs. Additionally, the needs of subwoofers versus the other channels can be drastically different. [*=1]Without using parallel outputs, they do not support impedances below 2Ω. So, unlike the DCA 1222, which can run down to 1.6Ω (e.g. five 8Ω surround speakers can all be wired in parallel), you either need to parallel two channel outputs to pick up the current capability or break up the string into two zones (per side) so, again, needing 4-channels to handle the side surrounds or using an 8-channel amplifier like the CX-Q 4K8 and likely have a couple of channels left over, which you may or may not have a use for. Or you could use dummy-load resistors to get the impedance back into the 2Ω-8Ω range. [*=1]Compared to the DCA amplifiers, they are physically noisy. In a projection booth, it is a non-issue as the projector is bound to be many times noisier than the amplifiers. However, if you plan on remote-mounting them (behind the screen), you will likely need to have some form of noise mitigation, as described above. [*=1]They have a bit of “hiss” associated with them. The more efficient your speakers are, the more likely you will hear it, as compared to the very quiet DCA line of amplifiers. In QDS 9.x.x (and refined over the various versions), they introduced a Power Saving feature for the Q amplifiers. It is configurable as to when it engages, if at all. In addition to saving power by putting the amplifier outputs (only) into a very temporary standby, it also, effectively, mutes the amplifier so you won’t hear the hiss. The PowerSave is on a channel-by-channel basis. It unmutes instantly so you don’t need to worry about it cutting off dialog or music. Part of the configuration includes how long there has to be no signal before it puts a channel into PowerSave (minutes, typically).

If you have a quiet screening room (noise criteria below NC30), you will likely find this line of amplifiers too “hissy.” Most commercial cinemas will likely never notice it due to the HVAC’s background noise level, let alone once an audience is seated. I don’t want to give the impression that it is like a mistuned radio station. It isn’t anything like that. They are noisier than our good friends, the DCA line of amplifiers.

SPA-Q Amplifiers I don’t want to spend too much time (on this already longish blog) on the SPA-Q line of utility amplifiers other than to make sure you know that they exist and that they may fill a need within your design.

• At present, they come in 2 and 4 channel versions with up to 60-watts per channel of output. They can be bridged for double the wattage but they cannot parallel their outputs for higher current. They are optimized for 4Ω and 8Ω but can play down to 2Ω. They also support Hi-Z (e.g. 70v) speakers.
• They are ½ of 1U of rack space so you can get up to 8-channels in 1U of rack space.
• They come with 2-channels of Flex Audio I/O as well as 4-GPIO terminals.

Where I think they can come in handy for cinemas would be for:

• Booth Monitor amplifier for when the DCIO’s 10W amplifier is insufficient.
• VIP room where you may wish to provide a 5.1/7.1 mix to that space on its own fader/EQ. The Flex I/O could provide a line level signal to a powered subwoofer. Just make sure that the VIP room audio (and light) doesn’t “leak” into the main theatre space such that you get a phantom rear-surround system!
• Lobby/Hallway speakers using a distributed Hi-Z system. They behave the same as CX-Q with respect to voicing and Intrinsic Correction™. Q-SYS does have multiple lines of utility speakers (ceiling, pendant, surface) to facilitate the lobby and entertainment center spaces.

Conclusion
Well, that was quite a bit of dialog and examples for just hooking up an amplifier! And, at the end of the day, that is really all it is. You drag the amplifier (or representation of an amplifier) into your design and hook it up. What I was hoping to convey in this particular blog is how to get the most out of your amplifier choice, particularly the CX-Q line of amplifiers in your designs.
Another aspect is to understand how powerful having a common voicing component that should make tuning go significantly faster and better. Once you have the voicing component and the speaker components, the first time (including Intrinsic Correction™), configuring a system in Q-SYS will go significantly faster and better than with other DSP implementations or conventional analog topologies.
There is a lot more technology and flexibility in these amplifiers than what we had in linear amplifiers.
©2024 by Steve Guttag

[Page 4 of 4, Blog 5, End of Blog]

[Leo Enticknap]

I have a customer who has requested that the mute button on the UCI be changed such that engaging it causes a fade out over three seconds, but releasing it restores the previous level (or whatever level the fader was changed to while muted) instantaneously.

I've thought about this and played around in Designer, but can think of no way to implement the request exactly. The nearest I've got is to use a gain ramp component placed between the master fader and the final output to the amps. I then added a block controller containing a "fade out" button, which triggers the gain ramp and then engages the regular master fader mute. It works but is a bit clunky, because it necessitates two buttons, one to trigger the fade out and another to restore the audio. Just wondered if someone had figured out a more elegant way that they are willing to share...

[Steve Guttag]

I had something similar. They wanted an adjustable fade rate so that they could time fade outs/ins.

Screen Shot 2024-12-22 at 12.04.55 PM.png

How it works seems a bit complicated because I did it without any scripting...all logic and "free" components:

Screen Shot 2024-12-22 at 12.08.15 PM.png

The first part of the equation was to divorce the Mute function from the fader and merely put this container in line with the audio, post selector. The Value Steppers are the Up/down values. In order to get ½-second increments, I let the Value Steppers have a range double what is needed and then multiply that by 0.5 (the Float custom Controls that feed a Value Product). Those two (up time/down time) get loaded into the next Custom Control as float values with a Toggle button and those values are sent onto a Control Router that is controlled by the toggle button. The toggle is controlled by the mute control (coming into the container on pin 11). These feed a gain component that is permanently being held to increase or decrease, depending on the mute status. The Control Delays are VERY short (10ms) and only serve to ensure that the ramp time is loaded before the Decrease/Increase are selected.

If you were to set the increase time to 0 and to use a Momentary button instead of a toggle, it should do what you want, if I read your description correctly.

Confirmed. This should do what you ask:

Screen Shot 2024-12-22 at 12.26.02 PM.png

I just added a Momentary button connected to its trigger pin (11). Press it, it fades at the speed of the left timer. Release it fades at the speed of the right timer...set to 0 is instant on.


FadeMute220601.quc.zip

[Elia Orselli]

Wouldn't you get a similar result using the gain ramp component as replacement for the normal gain block?

Connected with a flip-flop you have a momentary (toggle) button to trigger the two states: A would be the desiderd gain and B -100dB would act as mute. And if you have scripting lincese you can integrate the Dolby Fader component to control the A gain level
immagine.png

[Steve Guttag]

I'm guessing that should probably work...it would be better if the Gain Ramp worked in emulate mode so you could flesh everything out before pushing it live. For whatever reason, the Gain and Target Rates do not work in emulate so you don't know if you have everything configured right until you are live.