Dante DVS audio glitches - how best to configure?

[citysoundman]

I've been running Dante DVS on a Mac Studio for capturing multichannel audio at live event conferences. Anywhere from 16-24 track recording. On my recent job, I picked up some random audio spike/glitches across all tracks, it happened 5 times throughout the day. It's not a clock issue, since no clock errors were triggered.

I haven't encountered this issue before, and I'm trying to figure it out - could it be due to using Aux I/O for DVS? I'm using DVS for input only through AUX i/O, and a Focusrite Scarlett USB interface for monitoring, which is set as the primary playback engine device.

FYI on an old job I had DVS as the playback engine main device, and Scarlet as Aux I/O, but had some routing issues in DVS. When I swapped them (DVS to Aux I/O) the routing problem went away.

[JCBigler]

What is the main hardware that you're pulling the Dante stream from? And what kind of network switch are you using?

I don't understand how you are routing DVS to the Scarlet, since there's no Dante port on the Scarlet and there's no way to route actual audio out of DVS without a Dante enabled audio interface. It sounds like you should be using Dante VIA to do this.

The only other thing I can recommend checking without knowing a whole lot about your full set up is to make sure that the Dante Firmware and DVS are all on the correct current version.

I've seen spikes and clicks occasionally. Could be due to one of the settings in the network switch you're using. It can certainly also be a clock issue.

[uptheoctave]

Originally Posted by JCBigler

What is the main hardware that you're pulling the Dante stream from? And what kind of network switch are you using?

I don't understand how you are routing DVS to the Scarlet, since there's no Dante port on the Scarlet and there's no way to route actual audio out of DVS without a Dante enabled audio interface. It sounds like you should be using Dante VIA to do this.

The only other thing I can recommend checking without knowing a whole lot about your full set up is to make sure that the Dante Firmware and DVS are all on the correct current version.

I've seen spikes and clicks occasionally. Could be due to one of the settings in the network switch you're using. It can certainly also be a clock issue.

He said how, using AUX IO (Pro Tools Audio Bridge).

[uptheoctave]

Originally Posted by citysoundman

I've been running Dante DVS on a Mac Studio for capturing multichannel audio at live event conferences. Anywhere from 16-24 track recording. On my recent job, I picked up some random audio spike/glitches across all tracks, it happened 5 times throughout the day. It's not a clock issue, since no clock errors were triggered.

I haven't encountered this issue before, and I'm trying to figure it out - could it be due to using Aux I/O for DVS? I'm using DVS for input only through AUX i/O, and a Focusrite Scarlett USB interface for monitoring, which is set as the primary playback engine device.

FYI on an old job I had DVS as the playback engine main device, and Scarlet as Aux I/O, but had some routing issues in DVS. When I swapped them (DVS to Aux I/O) the routing problem went away.

I've not tried it but I can in a day or so as I'd like to know but speaking in general terms and assuming that the basics are covered then the things I'd be looking at are as follows:

1. What latency value did you set DVS to in DVS itself?

2. What hardware buffer size did you set in Pro Tools?

3. Was this on a mixed use network (with other audio/data/voice etc or was it on its own gigabit or better Dante network with no other traffic?
Does your network switch have EEE disabled? This is sometimes important.
If you use unmanaged switches, do not use Ethernet switches that support the EEE, because you cannot disable EEE operation in these switches. EEE is problematic because it reduces power consumption during periods of low network activity. In theory it shouldn't cause an issue but we know it does because of how *some* network switches implement it.

Here is a list of brands and models we know are incompatible with Dante because of this.

https://assets.audinate.com/wp-conte...audinate-1.pdf

This list is pretty comprehensive but there will be others not on the list that exhibit this behaviour.

5. Did you set up QoS? QoS is only required for 100Mbps or mixed 1Gbps/100Mbps networks. It can be good on mixed-use networks. It is not required for dedicated, all gigabit, Dante-only networks. When it is used, it must be configured with strict priority. I've seen people bugger up their Dante network by implementing QoS poorly when it wasn't needed.

6. Was IGMP snooping turned on or off? It is recommended that it be turned on if using multicast. Read THIS.

7. What switch brand/model did you use? I prefer Cisco switches but they are complex and can give you enough rope to well and truly hang yourself. Finding unmanaged switches that don't support EEE is increasingly difficult. I used to recommend the Netgear GS108 but I think they now support EEE.

8. Did the devices self assign IP or did you have a DHCP server or use fixed IP?
It is helpful to know that Dante devices continue looking for a DHCP address even when self assigned. This *shouldn't* cause an issue but is worth knowing and as part of a testing methodology I would use DHCP or assign fixed IP just to be sure.

Dante uses a distributed Leader Clock election protocol that automatically selects the best clock for the network, based upon information advertised by each Dante device.
'Random' spikes have been observed when opening Dante Controller partly due to this election protocol. I think it best to avoid opening Dante Controller or making any changes whatsoever when recording.

I don't especially like DVS- I find it flakey and annoying to use but it should be able to do what you want it to do. Did you test this before being on site? If this was my job to do I would have probably used something other than DVS

I should have a chance to test this by the weekend.
Will report back.

I might write a 'So you want to use Dante?' primer at some stage, because often the same issues crop up with clients and other audio pros.

Likely this is a Dante/DVS issue, simply based on probability, but just to be sure have you separated Dante and the Focusrite for testing? Use Pro Tools just with DVS and observe?
Also, try with another DAW.
It is good to have a DAW on hand that has no plugins enabled, simply to act as a troubleshooting step.

Or drag all your AAX plugins to the 'Unused' folder and relaunch Pro Tools.

[citysoundman]

Thanks for the replies on this. FYI I contacted Audinate support and they said that it wasn't a clock/sync problem, if it was then I would have seen errors on my log.

To supply a bit more detail, the Dante network was set up by a live sound company, they did the full audio installation which included wireless lavs and handheld mics, playback system for the hotel ballroom, Yamaha FOH console, and their Pro Tools recorders. I piggy backed onto their dedicated Dante network. They were also recording with Dante but not using DVS. They had hardware interfaces connected to the Dante network, feeding their Pro Tools recorders, and they didn't get any glitches like I did. So my issue was specific to DVS on my Mac. They also said they don't 'trust' DVS.

Some answers for @uptheoctave - I really appreciate your detailed reply! Very helpful tips :)
Latency was 10ms
PT hardware buffer, not sure, probably 256
Network admin did turn off IGMP snooping for my Mac. This was needed because I wasn't locking to Dante clock. Turning off snooping fixed it.
IP was DHCP for me.
My Pro Tools system had no 3rd party plug-ins installed. But I was using EQ3 and Avid Pro Limiter on my inputs to process audio. Although I can't imagine the plug-ins would cause this - I've used them before in this type of recording.

FYI I've used this exact setup on 3 previous gigs with same client. I never had these glitches before. But each gig has a different sound installation crew so different network each time. My main question is what's the best way to configure DVS in Pro Tools - is using AUX IO for DVS input a potential issue? If so maybe I should use DVS as the main Playback Engine device?

[citysoundman]

Originally Posted by JCBigler

I don't understand how you are routing DVS to the Scarlet, since there's no Dante port on the Scarlet and there's no way to route actual audio out of DVS without a Dante enabled audio interface. It sounds like you should be using Dante VIA to do this.

Pro Tools Aux IO (Mac only feature) lets users add additional external audio interfaces or internal routings, in addition to the primary interface selected in the Playback Engine page. Dante DVS shows up as inputs and outputs on the IO page when Aux IO is enabled. I was using only the inputs from DVS to feed my record tracks. The Scarlett was set as the main interface and I was using it for monitoring.

Originally Posted by JCBigler

The only other thing I can recommend checking without knowing a whole lot about your full set up is to make sure that the Dante Firmware and DVS are all on the correct current version.

Thanks, they were all current versions.

[Top Jimmy]

I had a problem with glitches in the audio with a laptop receiving 32 channels via DVS. My MacBook can do it reliably and I always capture with Tracks Live.

Aux I/O requires real time SRC and if I remember correctly the tech notes on it state that it shouldn’t be used for critical audio paths because of the possibility of artifacts. If I were you, I’d use DVS as the primary audio interface and the Scarlett via aux I/O.


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[citysoundman]

Originally Posted by Top Jimmy

I had a problem with glitches in the audio with a laptop receiving 32 channels via DVS. My MacBook can do it reliably and I always capture with Tracks Live.

Aux I/O requires real time SRC and if I remember correctly the tech notes on it state that it shouldn’t be used for critical audio paths because of the possibility of artifacts. If I were you, I’d use DVS as the primary audio interface and the Scarlett via aux I/O.


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thanks for the reply Jimmy! I found a good doc on Aux I/O and while the potential issues don't seem to apply to my situation, it does make sense to keep DVS as the primary interface.

On a previous gig, I actually had been using DVS as my primary interface and the Scarlett on Aux I/O, and I encountered a routing issue with DVS. A few of the input channels weren't coming in on the expected channels, it was a weird situation, with a couple of inputs not getting to Pro Tools. This got corrected when I switched DVS over to Aux I/O. Maybe it was a problem within Dante controller.

But yeah I'm feeling that like you said if it's a critical recording situation best to stay on the main playback engine connection.

[Top Jimmy]

Originally Posted by citysoundman

A few of the input channels weren't coming in on the expected channels, it was a weird situation, with a couple of inputs not getting to Pro Tools. This got corrected when I switched DVS over to Aux I/O.

Anytime I’ve had routing weirdness in Pro Tools, my solution has been to delete all paths on the input tab and then hit the default button. Then I’d also do the same on the output and bus tabs. Just hitting the default button alone doesn’t always fix the issue.


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[citysoundman]

Originally Posted by Top Jimmy

Anytime I’ve had routing weirdness in Pro Tools, my solution has been to delete all paths on the input tab and then hit the default button. Then I’d also do the same on the output and bus tabs. Just hitting the default button alone doesn’t always fix the issue.


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Nice, thank you!