How to manually time align multiple subs to acoustic timing reference speaker?

[serko70]

Ok. So if I understand you correctly, are you saying that I should manually convert the actual distance (2,32 meters) to what the AVR thinks the distance is? 2,32 m / 343 m/s = 6,76 ms, so that equals 2,029 m (6,76 ms / 300 m/s)?

Is that the only manual SOS adjustment I need to do?

Yes, AVR only applies the correct delay for your actual distance with that setting due to lower speed of sound it uses. This and REW's sos set up to 300 will suffice.

 

[Spennis]

Yes, AVR only applies the correct delay for your actual distance with that setting due to lower speed of sound it uses. This and REW's sos set up to 300 will suffice.

Got it. An unexpected but important discovery

Tha actual distance of SBL is about 3,71 m and SLA is 2,60 m.

Is there a benefit of measuring the speaker distances with REW, or might it be better to do it by hand with a laser?

 

[serko70]

Got it. An unexpected but important discovery

Tha actual distance of SBL is about 3,71 m and SLA is 2,60 m.

Is there a benefit of measuring the speaker distances with REW, or might it be better to do it by hand with a laser?

Always use REW, it takes into account internal delays.

 

[Spennis]

Volume levels are results of REW "Align SPL" for 2.5 octaves each way around 100kHz which gave the least variation between your 1/1 smoothed speaker responses.


You certainly can but this will decimate the IR and cause its sampling rate to drop (unless you have unticked "decimate IR" in REW default settings). IR peak shape will look more handsome but will be less accurate.

I'm trying to replicate what you did. Following you tutorial, I ran "Align SPL" and added the SPL offset after first having cross-corr aligned and vector averaged each speaker's measurements. I did this for the speakers separately, and the subwoofers separately. This is all in the .mdat file I supplied.

When did you "Align SPL"? Straight away with the .mdat file I supplied, or after EQ? Furthermore, did you use 5 octaves around 1 or 10 kHz? I suppose it was not 100 kHz

In case you have time and are curios about why we got different results, I also uploaded the RAW measurements (named "...tep 1 B - Measurements in order + mic position C removed.mdat".). In that file, there are six mic positions for each speaker (0 A, 1 A, 2 A, 0 B, 1 B and 2 B) where "0 A" is the MLP to which all the others are to be time aligned. There are also measurements for SW1, SW2 and SW1+2 for all six positions (but I did not use the "dual sub" measurement, it was just for reference).

Is your "adjust clock with acoustic reference" option ticked in REW?

I checked, it is ticked.

Audyssey has inverted both your subs and has decided to apply a 0.78m relative delay to the second sub (2.6ms in 300m/s sos terms) and moved the combined response to 9.12m which is not applicable.

Did you find that in the .ady file? If I open that file in the MultEQ editor app, I see that Audyssey has set SW1 to 6 m and SW to 8,34 m (which is equal to the center speaker distance of 2,34 m + SW1). Is the maximum distance cap a feature of Audyssey or Denon/Marantz? They should really adress this issue.

Your extreme subwoofer delay remains a mystery unless it's caused by the center speaker (which also strangely seems to need around -6-7dB volume alignment). I'd try using another speaker as acoustic timing reference and remeasure the sub to opt out some possible causes. Also, if there's a phase dial on the subs, move it to 0 degrees.

How could the subwoofer delay be caused by the center speaker? As noted, Audyssey correctly detects the center speaker distance and also find the subwoofers to be far away.
I can try and measure with another reference just to try, but I need to use the Atmos sweeps in the end to be able to calibrate my 7.2.4 system. Phase dial is at 0 degrees as instructed in the subwofer manual.

@serko70: Always use REW, it takes into account internal delays.

OK, thank you. So if it turns out REW gets it wrong for some reason, I should use Audyssey's distance settings rather than laser measurements?

 

[serko70]

You've to align SPL before any EQ, create a target curve from the aligned speakers average and EQ every speaker to that target level. 5 oct around 1000Hz, sorry for the typo.
To see Audyssey's subwoofer settings, open the ady file you have shared in the online Json editor and dig into last 2 channels.
Maximum distance is related to the DSP chip in the Sound United gear.
Center channel is producing the acoustic chirp at the beginning and at the and of each measurement and REW calculates all timing based on the time between these two chirps.

In case you have time and are curios about why we got different results, I also uploaded the RAW measurements (named "...tep 1 B - Measurements in order + mic position C removed.mdat".). In that file, there are six mic positions for each speaker (0 A, 1 A, 2 A, 0 B, 1 B and 2 B) where "0 A" is the MLP to which all the others are to be time aligned. There are also measurements for SW1, SW2 and SW1+2 for all six positions (but I did not use the "dual sub" measurement, it was just for reference).

I will try to look into it later. I hope you used a different speaker as acoustic reference this time.

 

[Spennis]

You've to align SPL before any EQ, create a target curve from the aligned speakers average and EQ every speaker to that target level. 5 oct around 1000Hz, sorry for the typo.
To see Audyssey's subwoofer settings, open the ady file you have shared in the online Json editor and dig into last 2 channels.
Maximum distance is related to the DSP chip in the Sound United gear.
Center channel is producing the acoustic chirp at the beginning and at the and of each measurement and REW calculates all timing based on the time between these two chirps.

I will try to look into it later. I hope you used a different speaker as acoustic reference this time.

Thank you. Strange that we got different SPL offsets. I tried 5 octaves around 1000 Hz, gave me different results.

I hope Denon/Marantz will fix this, should be a priority. Wonder if the same limit applies to Dirac in the 2023/2024 lineup.

Sorry, it's the same acoustic reference, but the RAW measurements prior to any cross correlation alignment, vector averaging etc. I'm going to try a different acoustic reference, but it will take a few days until I have the opportunity.

 

[serko70]

I tried 5 octaves around 1000 Hz, gave me different results

Did you use 1/1 octave band smoothing beforehand?

 

[Spennis]

Did you use 1/1 octave band smoothing beforehand?

I did not. Should I? If so, should I remove that smoothing after SPL aligning?

 

[Spennis]

Quick update with some interesting info:

I reached out to both XTZ, Denon, Audyssey and Dirac to ask about these delay and delay setting issues.

Firstly, XTZ responded that they actually have a new firmware for my subs' DSP chip that improves the delay, so I will send them my plate amps for a firmware update.

Secondly, both Denon and Dirac told me that Dirac is not capped to a maximum of 6 meters between speakers in the 2023/2024 Denon AVRs that support Dirac. Dirac said the maximum delay difference is 50 ms, and Denon said the maximum distance difference corresponds to 18 meters (i.e. almost the same). Did you know about this @serko70 ?

Denon and Audyssey also confirmed that Audyssey is capped at 6 meters still, and Audyssey does not seem very happy about this and encouraged me (and others) to complain to Denon. So, we should all send Denon an e-mail if we want this resolved.

Thirdly, I am going to remeasure my system with another sub to diagnose the delay issue, as well as with a different acoustic reference speaker, as soon as possible. I will also remeasure with my current XTZ subs once I have the new firmware

 

[serko70]

Quick update with some interesting info:

I reached out to both XTZ, Denon, Audyssey and Dirac to ask about these delay and delay setting issues.

Firstly, XTZ responded that they actually have a new firmware for my subs' DSP chip that improves the delay, so I will send them my plate amps for a firmware update.

Secondly, both Denon and Dirac told me that Dirac is not capped to a maximum of 6 meters between speakers in the 2023/2024 Denon AVRs that support Dirac. Dirac said the maximum delay difference is 50 ms, and Denon said the maximum distance difference corresponds to 18 meters (i.e. almost the same). Did you know about this @serko70 ?

Denon and Audyssey also confirmed that Audyssey is capped at 6 meters still, and Audyssey does not seem very happy about this and encouraged me (and others) to complain to Denon. So, we should all send Denon an e-mail if we want this resolved.

Thirdly, I am going to remeasure my system with another sub to diagnose the delay issue, as well as with a different acoustic reference speaker, as soon as possible. I will also remeasure with my current XTZ subs once I have the new firmware

İ had heard about that some time ago. Dirac also can apply more crossover frequencies in the same reciever compared to Audyssey. I'd support Audyssey if there's a way we can help to convince Sound United although I seriously doubt it.

 

[sm52]

new firmware for my subs' DSP chip that improves the delay

How can firmware improve latency? The delay is caused by drivers. The amplifier introduces such small delays that they are not worth talking about.

Secondly, both Denon and Dirac told me that Dirac is not capped to a maximum of 6 meters between speakers in the 2023/2024 Denon AVRs that support Dirac. Dirac said the maximum delay difference is 50 ms, and Denon said the maximum distance difference corresponds to 18 meters (i.e. almost the same). Did you know about this @serko70 ?

You should consider replacing your AVR with a 23/24 model that supports Dirac.

So, we should all send Denon an e-mail if we want this resolved.

If after such a letter there are no changes.

 

[Spennis]

İ had heard about that some time ago. Dirac also can apply more crossover frequencies in the same reciever compared to Audyssey. I'd support Audyssey if there's a way we can help to convince Sound United although I seriously doubt it.

Interesting. Worth a try!

You should consider replacing your AVR with a 23/24 model that supports Dirac.

If after such a letter there are no changes.

I am considering it for a number of reasons. This just gave me another one.

How can firmware improve latency? The delay is caused by drivers. The amplifier introduces such small delays that they are not worth talking about..

I don't know. If XTZ says they can improve it, I'm willing to try.