1 Topic by DanRand (edited by DanRand 2013-01-08 15:19:04)

  • Registered: 2011-11-02
  • Posts: 55

Topic: Fireface UCX - Incorrect Latency (Logic Ping)

Hi,

Just bought a UCX over christmas for use with my Digiface (adat in/out 2).

However, Logic is giving me incorrect Ping and click-based Loopback results, with outputs 5-6 on the UCX looped-back to inputs 5-6.

Logic is reporting a Ping/offset of +1 when the UCX is running from it's USB drivers, as clock master.

Also, when running the UCX from the Digiface (with UCX as adat "slave", either as clock master or slave), Logic is reporting a Ping/offset of +48 samples, 20 more than it should be.  According to this thread ADAT Latency - Fireface UCX, Logic should be reporting a Ping/offset of no more than 28 samples (21 for AD/DA, and 7 or less for TM FX).

The only sample rates that are showing a ping of 0 are 88.2k and 96k.  44.1k, 48k, 176.4k and 192k all show a ping/offset of +1.  Digital/SPDIF loopback is reporting a ping of -20 samples, and ADAT loopback is reporting -21 samples.

I am testing the latency from a completely empty Logic project, with absolutely no other plugins running.  I've completely removed the drivers & preferences, and tried installing UCX drivers 1.68, 1.76 and 1.78, and refreshed the firmware.  None of this has helped.  Incidentally, when I ran a UFX from the same Mac in November, the UFX correctly reported a ping of 0.  Nothing on my Mac has changed since then (Logic version the same, OS X version the same).

Logic should be reporting a ping/offset of 0 from it's USB drivers.  And 28 or less when hanging off the Digiface...

Please help, this is a head scratching problem.

Screen shots attached below.

Thanks,

D

http://rand.me.uk/Audio/Manufacturers/RME/Wrong_UCX_Latency_-_Logic.png

http://rand.me.uk/Audio/Manufacturers/RME/Wrong_UCX_Latency_-_Matrix.png

http://rand.me.uk/Audio/Manufacturers/RME/Wrong_UCX_Latency_-_TotalMixFX.png

http://rand.me.uk/Audio/Manufacturers/RME/Wrong_UCX_Latency_-_Fireface_USB_Settings.png

Logic 9.1.8 (1700.67) (32-bit) - OS X Lion 10.7.5
Digiface <-> [Fireface UCX & Prism Orpheus - ADAT]

2 Reply by MC

  • MC
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  • Registered: 2007-04-06
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Re: Fireface UCX - Incorrect Latency (Logic Ping)

I don't see where the probem is with a value of +/-1. Indeed the delays are not full samples, but fractions of, so there is no 100% accuracy.

The problem with the Digiface/UCX combo is that you run them as aggregate device. There is an option to decouple their clocks in software and use hardware clocking, which reduces latency in that mode.

Regards
Matthias Carstens
RME

MC's Website

3 Reply by DanRand (edited by DanRand 2013-01-09 16:57:44)

  • Registered: 2011-11-02
  • Posts: 55

Re: Fireface UCX - Incorrect Latency (Logic Ping)

I'm not concerned with extra latency of +1 sample per se.  Everybody says that RME drivers report a ping/offset of 0, and that's certainly my experience with the Digiface and UFX.  I'm concerned that my drivers/UCX are doing something strange.  Other users on the web have reported that the UCX returns a ping/offset of 0 with Logic, so I'm just wondering why mine isn't.

Also, I'm not running the UCX/Digiface as an aggregate when I get a ping/offset of 48 samples.  I'm running the UCX as a stand-alone AD/DA converter (with USB cable unplugged) and plugged into Digiface ADAT i/o ports 2.  This is when I'm getting a ping of 48 samples.  Don't think I mentioned aggregation anywhere?  It should be 28 samples or below?  21 samples for AD/DA and below 7 samples for TotalMix FX and ADAT routing.

To clarify, the UCX USB driver is reporting a ping of +1; I don't have anything else connected to the UCX when testing it's USB driver, although I've looped-back the ADAT out/in ports and likewise the SPDIF out/in.  Digiface + UCX (UCX stand-alone, USB unplugged) is reporting a ping/offset of +48.  A digital loopback (ADAT port 3 Out toslink connected to ADAT port 3 In) on the Digiface reports an offset of 0, as expected.

Thanks for your time,

D

Logic 9.1.8 (1700.67) (32-bit) - OS X Lion 10.7.5
Digiface <-> [Fireface UCX & Prism Orpheus - ADAT]
  • Wiz
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  • Registered: 2007-07-04
  • Posts: 69

Re: Fireface UCX - Incorrect Latency (Logic Ping)

My ucx reports ping of 1 sample in logic.

5 Reply by DanRand (edited by DanRand 2013-01-09 17:00:29)

  • Registered: 2011-11-02
  • Posts: 55

Re: Fireface UCX - Incorrect Latency (Logic Ping)

Thanks Wiz, good to know I'm not the only one getting a ping of +1 at 44.1k/48k.

I'm not really concerned about the higher than expected latency, I'm just trying to determine if my latency figures are correct, and that my UCX is working properly.

What I'm more concerned about is the ping/offset of 48 samples when running the UCX stand-alone via ADAT only (USB unplugged), running off the Digiface ADAT ports 2.  This seems contrary to the advice given to me here.

Either 48 samples is correct and that's how the UCX should be working in stand-alone, or I'm experiencing around 20 samples of additional latency somewhere.

As I said, I'm just trying to determine if my UCX is working correctly, I'm not complaining about the latency figures, which are still vastly better than running my Orpheus as ADAT stand-alone via the Digiface.

Perhaps RME could confirm my findings of 48 samples of latency for the UCX in stand-alone mode (ADAT connections only)?

Thanks,

D

Logic 9.1.8 (1700.67) (32-bit) - OS X Lion 10.7.5
Digiface <-> [Fireface UCX & Prism Orpheus - ADAT]

6 Reply by MC

  • MC
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Re: Fireface UCX - Incorrect Latency (Logic Ping)

I checked and confirm your findings. In stand-alone mode the UCX does not use the low latency filters for AD and DA conversion. This will be fixed in the next firmware update.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2011-11-02
  • Posts: 55

Re: Fireface UCX - Incorrect Latency (Logic Ping)

Excellent news.  Thanks very much :-)

Logic 9.1.8 (1700.67) (32-bit) - OS X Lion 10.7.5
Digiface <-> [Fireface UCX & Prism Orpheus - ADAT]

8 Reply by DanRand (edited by DanRand 2013-01-11 17:19:56)

  • Registered: 2011-11-02
  • Posts: 55

Re: Fireface UCX - Incorrect Latency (Logic Ping)

Also, could you please ensure that the UCX uses the low latency filters for AD/DA conversion when in a stand-alone configuration, but with the USB cable left plugged in.

With the USB cable still connected, I'm also getting a ping of +48 (@44.1k/48k) whilst using the UCX with a stand-alone routing (UCX ADAT In -> Analog Out -> Analog In -> ADAT Out).

This will allow me to access TotalMix FX via USB, but utilize ADAT from/to the Digiface to send/receive audio streams to/from the UCX.  So, effectively, ADAT stand-alone with USB control of mixer/settings.

Many Thanks,

D

Logic 9.1.8 (1700.67) (32-bit) - OS X Lion 10.7.5
Digiface <-> [Fireface UCX & Prism Orpheus - ADAT]

9 Reply by MC

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Re: Fireface UCX - Incorrect Latency (Logic Ping)

Update: positive news first: the UCX DOES use the Low Latency filters in any mode (normal, stand-alone, CC). That is important as you can be sure the sound quality is always the same, no matter how the unit is used. The not so positive news: we are still getting our heads around where this additional latency originates. We are talking about 15 to 20 samples unexpected delay when using the unit as in the above example, as AD/DA converter driven from the ADAT I/Os. Will update again as soon as the fog vanishes...

Regards
Matthias Carstens
RME

MC's Website

10 Reply by DanRand (edited by DanRand 2013-01-17 01:12:33)

  • Registered: 2011-11-02
  • Posts: 55

Re: Fireface UCX - Incorrect Latency (Logic Ping)

Good to know you're on the case.  As I said, mainly just making sure I'm getting the same latency figures everyone else is,  although a 20 sample drop in stand-alone latency would be welcomed.

I've just done a ping (UCX ADAT stand-alone) at 88.2/96k and I'm getting a ping/offset of 83 samples.  Don't know what the non-converter/TM FX delays are supposed to be with the UCX at Double Speed, so hard to compare with the figure of +48 at Single Speed.

Just thought I'd complete the picture a little more...

Thanks,

D

Logic 9.1.8 (1700.67) (32-bit) - OS X Lion 10.7.5
Digiface <-> [Fireface UCX & Prism Orpheus - ADAT]