SQ / Dante / StageBox questions

[Chris]

Hello – firstly my apologies, it’s a bit of a long one!

Quick Summary
I’m looking to get back into Audio/Music, I’m a bit rusty but can normally find my way around an analogue console. I’m looking at an SQ with these goals in mind: recording drums (so need channel count ~12), play instruments (synths etc) without using a computer, potentially live sound and in the long term low latency recording. I’m looking for a flexible solution, hence why I’m not looking at two ‘8 pre’ audio interfaces which would only cover my recording needs. I’ve seen the information where some users have USB challenges with the SQ, I am not in the USB fan club anyway, so realistically looking at Dante longterm for its networking and flexibility, although slink maybe a possibility too for stage boxes, but would like to avoid dedicated switches. I won’t bore you with too much background information, hopefully I have the important points covered.

My Questions – I’ll try and keep my questions brief and hopefully yes/no or a numeric where possible.
1) What is the lowest latency you can achieve on the Dante network with the DT168s in a live sound environment? Is 250us possible in the right environment? (I’m assuming they work great, but just trying to understand the technology and its limits)
2) There is a thread in the troubleshooting section which highlights the delay between the inputs on the rear and the inputs on the AR2412 stage box. A) What is the smallest delay step available on a channel? B) Is phase coherence possible between the two inputs? (I saw the Avantis can add delay down to the sample – which is really cool)
3) From the DX/gigaACE white paper, the DX has a latency of 8 samples/83us.
If I connect SQ -> DX168 -> DX168 are both the DX168s running at 83us (and phase coherent with each other) or is the second one delayed by a further 83us, therefore total 166us (or some other value)?
4) From the Dante marketing material, all the devices should be synced down to the sample so I assume that multiple DX168s will be phase coherent – is this the case in the real world?
5) If I have 3 DT168s and configure 48 inputs running on Dante, with the 64×64 card, I’m assuming I can still use the remaining 16 ins on the Dante card (and 16 associated outs) for channel inserts and send to an external FX unit on the Dante network. Is my understanding correct?
I’m assuming the routing for this would be:
DT168 -(dante)-> SQ -(dante)-> EXT FX -(dante)-> SQ
rather than:
DT168 -(dante)-> EXT FX -(dante)-> SQ
6) From my understanding the second path [DT168 -(dante)-> EXT FX -(dante)-> SQ] should in theory be possible to setup within the Dante network but I would lose the ability to control/adjust the preamp on the DT168. A) Is this correct? B) Is it only the preamp adjustment that is lost?
7) A) Where is the channel processing completed, is it in the stage-box or the console? B) do the stage boxes contain the XCVI FPGA chip?
8) From a recording/Dante stand point and as I understand it from the Dante information, I should be able to configure the DT168 to send audio to the SQ and to my computer at the same time, obviously this would mean any processing on the mixer would be lost on the recording stream, but would be potentially lower latency. Is this possible on the DT168?

Have I missing anything obvious? Feel free to add comments or make alternative suggestions too 🙂

Thanks in advance.
Chris

[Nicola A&H]

Hi Chris, lots of good questions there!
1) Yes, 250us is possible for simple point-to-point connections. Higher latencies might be required when using multiple network hops.
2) The min delay on SQ is 1 sample on input channels, 2 samples on mix channels. So yes, you could manually compensate to align the inputs, but in most cases, unless the two sources are strongly correlated (an XY stereo pair for example), it doesn’t really matter. The acoustic delay from mic placement and actual sources on stage is likely to be far higher than any latency on audio transport.
3) The second expander will be further delayed.
4) I am not sure that Dante outputs will be synced across multiple devices. Dante sockets on the same device, yes, but my understanding from Dante certification is multiple devices will each have their own latency managed independently. I guess that’s a question for Audinate.
5) Yes, you can use all of your 64×64 Dante I/O. And yes, typically Dante FX would be patched from the SQ mixer or even inserted on a channel, rather than fed directly from the stagebox.
6) That’s correct, you would lose preamp control (gain, 48V and Pad). I’m not sure what you are trying to achieve but this would be a very unusual signal path.
7) With SQ, all processing happens in the mixer. The stagebox only handles preamps and ADC / DAC. It’s fundamentally different from our dLive system, where the MixRack IS the mixer, and the console is mostly a control surface.
8) Again, yes you can do that, but most people would just do a Tieline patch from the SQ to their computer for recording. Latency in the recording path isn’t really an issue unless you are doing overdubs.

I’ll let other users comment more broadly on the application and typical setups, but hopefully I’ve clarified some technical points above.

[Chris]

Hi

Excellent, thanks for the quick response and detailed answer. It’s all starting to make a great deal of sense!
For number 6 I was thinking you could have created the insert inside the Dante network, rather than route the audio through the SQ. This would remove the requirement for an input/output channel, reduce latency and network bandwidth.
However, I totally understand why this wouldn’t be the case as it would be completely different to how all other inserts work and add complexity.

I’m definitely going to look at Dante more closely.

Anyway thanks again for responses and your time,
Chris

[Jackson Harris]

Hi, I’m new to the forums so I’m not sure if this is the best place to put this, but I have a few questions as well, mostly on the same topic around Dante configurations.

We’ve been working on a whole new AV system and have started with the SQ7 with Dante as well as a DT168 on Stage. We really like the flexibility of Dante firstly being able to plug in anywhere on our network to access Dante as well as being able to effectively duplicate channels for full independent channel eq/fx/compression/etc since we’re mixing the show in several different environments (Large acoustically reflective room, a much smaller room, outside across a huge field, and online for a live stream). However, while we already knew we’d want a second mixer even without this consideration since we would still effectively have 4 guys mixing each area, being limited to 48 channels per board means we can only duplicate so many times before running out of channels. The other factor thrown into this is the thought of the any external effects to add potentially through the Waves card or otherwise. Our internal dispute is how best to move forward with this.

(Disclaimer: I am admittedly biased for the last option, but I hope to determine more objectively for my Team which makes the most sense for our current situation.)

The main options on the table so far are:
1. We get the new SQ5 board without the additional Dante card to save a mere $750 and just use Slink with tie lines from Dante as well as any external effects via USB with a computer. I feel like this option would add additional confusion/complication for some users should we need to re-patch or add additional inputs. But then even more predominantly, this would lose us our flexibility with Dante of being able to patch in anywhere on the network we’ve built for this. A potential scenario for this would be moving the smaller board outside if we ever want to use the full mixer for something more dedicated outside and/or to a isolated room in the building to mix the stream away from anything else.
2. Similarly, we get the SQ5 but with the Waves card to use with either a computer or even a SoundGrid Server which negates the $750 savings and even adds the possibility of more cost with the $1k Server while also losing the same benefits from Dante as the previous option. With both of the previous options any external effects would preferably not be run through a computer since the only computer we have for this is already managing several other workloads and I wouldn’t count on signal being close to real-time like it would with a dedicated server. And then again patching this would be a lot more complicated than it could be.
3. The option I’m leaning towards the most and want reasons for and/or against this is to get the SQ5 with Dante where connections, patching/routing, and configurations are, I would think, the simplest since Dante is already our main interface, and we have the most flexibility with managing devices, inputs, and outputs both physically and digitally. Further then offering a solution for external effects could easily be to just use the same temporary solution of a computer as before, but also for a SoundGrid Server is that there is a Dante option for SoundGrid Servers that we could invest in down the road.

Given external effects haven’t been on our plan or budget from the start of this, any consideration for it is extra; but I also don’t want to cut corners just to save a little. Also given we’re budgeting for a several thousand dollar overall AV upgrade and investment, we’re of the mindset that we want to it right and best the first time to have a solid system to last; thus is why the $750 for a Dante card is a relatively negligible amount. I’m all about getting the biggest bang for my buck while balancing quality over wastefulness in a budget. I’m not wanting to throw away money, I just want what we’re spending to make the most impact. Do you guys have any thoughts or feedback I could share with my team that we might not have considered and/or which of those three options makes the most sense?

[Yves Smit]

Hi Jackson,

I was thinking in a similar way and ended up with the SQ6+Dante card & DX168. Near future upgrade will be UAD Live rack + Focusrite Rednet d64r for easy dante patching of external I/O and UAD Processing inserts.
You can of course go the Waves direction in a similar fashion. This way you are future proof with Dante, don’t have to spend extra on the stagebox because it’s a bit cheaper with Slink. AND most importantly you can easily patch and route everything. You can also create tie-lines between the Slink stagebox directly to Dante. To set stagebox gain/48v/pad you do have to (temporarily) patch the channel on the mixer.
This also creates an easy upgrade path according to budget;
1: Mixer + dx168
2: Dante card for easy external I/O, think streaming/laptops I/O via ethernet (from other places in the building)
3: External Processing via Dante
4: Extra Slink DX168 (loop through) AND/OR Dante DT168 for I/O

Enjoy your system, whatever you choose!

[GGWO AV]

Hi everyone,

I’m new to the Allen & heath world and I have some questions. For our stage sound we are looking to purchase an SQ-5 that will provide sound to our Aviom personal monitors (thru the D400), to our physical monitors as well as our in-ears. I know that in order to have everything on Dante, I will need a Dante card for the SQ-5 but here are my questions:

1 – Do I have to go with the DT168 stage box and what are the advantages of that over the DX168?
2 – If I use the DX168, will it be on my Dante network when attached to the SQ-5 thru the SLink?

Thank you so much!

[Jackson Harris]

Hey GGWO AV,

I think you’ll need the DT168 for Dante. As far as I know, the DX168 only works with A&H’s systems like dLive DX Link or Slink, but someone could correct me on that.

As for how you’re doing monitors via the Avioms, have you considered just getting a Dante headphone unit and patching an Aux to each one? Then each person can use the SQ4You app to mix their own full mix with the Aux directly. That’s at least how I’ve been doing it lately and it makes it really easy for my stage members to use; they just select the channels they need and mix what they want to hear with that. Then it keeps the stage a tad clearer with the one ethernet to headphone unit on the floor than having an Aviom unit up on a stand near them. It makes it completely clear if you’re using wireless monitors like we’ve started adding.

There might be other options out there, but here’s a link to the headphone amp we’ve been using.

Virgil Dante Headphone Amplifier

[Martijn]

Hi GGWO,

The DT168 are Dante enabled boxes, The DX168 are DX (AH proprietary protocol) enabled boxes.
The DT’s need initial setup and can be mixed with any Dante enabled device.
The DX boxes are plug and play and always 96kHz (DT you can choose).
You can send the Inputs from the DX boxes thru Tielines (without processing) or thru direct outs/busses to an SQ Dante card.
The only disadvantage is that the SQ always have to on.
If you use the DT boxes depending on you config the SQ can be turned off.

In your case I would have a look @ the ME system as this would only require and extra slink card (Or you can use AB/AR audio racks).
This would lower your latency and will give more flexibility to your Personal Monitoring System. (40 channels instead of 16).

[Author]

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