Alignment Tool ?

[Gregory Livingstone]

I am trying to align a pair of subs using the USB input of a MiniDSP 2x4HD. Initial config was made by trial and error. I then tried using alignment tool. I could make better FR curves, but I found that making a curve with the settings I used during trial and error didn't match.

When making measurements, I configured loopback w/o an offset. In measure notes it usually reports delay of 0.0000 ms though at times it is 0.0001 ms. Is it valid to use the MiniDSP USB input this way?

With additional efforts with alignment tool, I noticed I could make FR curves that were very close to measured, however the offset were different with the actual measure delay being 4-5 ms higher. I am thinking it is worth using Alignment tool to generate a better FR and then add 4-5 ms by trial and error with measurements to align the subs. Does that seem reasonable?

If there is a better alternative, I am all ears.

 

[jtalden]

The 8.5 ms timing appears to be very close just based on the phase and SPL chart posted.
We need to use 'acoustic' timing reference rather than 'loopback' timing reference when using a USB mic.

 

[JStewart]

With additional efforts with alignment tool, I noticed I could make FR curves that were very close to measured, however the offset were different with the actual measure delay being 4-5 ms higher.

We need to use 'acoustic' timing reference rather than 'loopback' timing reference when using a USB mic.

To add to @jtalden ’s observation:
See Using a Timing Reference on this page https://www.roomeqwizard.com/help/help_en-GB/html/makingmeasurements.html
And this tutorial from MiniDSP https://www.minidsp.com/applications/auto-eq-with-rew/measuring-time-delay

My experience is using the alignment tool with a timing reference has always resulted in the measured response matching the calculated response.

 

[Gregory Livingstone]

The 8.5 ms timing appears to be very close just based on the phase and SPL chart posted.
We need to use 'acoustic' timing reference rather than 'loopback' timing reference when using a USB mic.

Are you indicating that a good sub integration should have as few phase transitions as possible? I was planning to find an alignment w/o the bass dips using the alignment tool and then add 4-5 ms, load that into 2x4, and measure (adjusting by .1 ms till I get the intended response). The ones I looked at have 3 transitions from 18 hz - 100 hz.

To get the acoustical reference, is it possible to make a file with REW using sub sweep that includes it and then play it thru USB interface? So is there a low frequency chirp or would a higher frequency chirp be picked up?

I was trying to get the subs aligned separate from the system(s) and then use the systems to EQ and time speakers / subs.

• I have a NAD C658 playing thru 7.1 inputs of a Marantz 8003 with Dirac. I may be fooling myself that Dirac will manage speaker / sub alignment. I care more about this being right, so an acoustical timing will have to use crossover to get sound to subs. My earlier efforts show that I was getting some bass out of the speaker providing the timing (the selected as unplugged). The speakers are bi-amp so I could disconnect the bass on the timing speaker (only thought of that recently). Would this be better than the trial and error above (I do think I can start close, the 4-5 ms difference seems consistent).
• The Marantz has older Audyessey with 6 measures.

 

[jtalden]

Are you indicating that a good sub integration should have as few phase transitions as possible?

Generally; The phase transition near 20 Hz is due to normal phase rotation and can be ignored. A phase transition near the XO frequency is also expected with an ideal setup. It would also be due to normal phase rotation. Others in the bass range are either interference due to SW timing or to the room setup. It is common to have one or 2 of these in typical setups.
Sound arrival timing to the LP position from the 2 subs should be reasonably close to each other to avoid unnecessary SPL dips. The room setup may cause other dips in the SPL. Those are due to room dimensions and locations of the SWs and LP .

I was planning to find an alignment w/o the bass dips using the alignment tool and then add 4-5 ms, load that into 2x4, and measure (adjusting by .1 ms till I get the intended response). The ones I looked at have 3 transitions from 18 hz - 100 hz.

Depending on the situation, that DIY approach is a reasonable one, but what is the limitation of the Dirac automated setup capability that requires the MIniDSP and manual setup steps? I may not be much help as I have no experience with Dirac capabilities or limitations.

To get the acoustical reference, is it possible to make a file with REW using sub sweep that includes it and then play it thru USB interface? So is there a low frequency chirp or would a higher frequency chirp be picked up?

REW can play a sweep from a file as explained in the link that JStewart posted.

I was trying to get the subs aligned separate from the system(s) and then use the systems to EQ and time speakers / subs.

• I have a NAD C658 playing thru 7.1 inputs of a Marantz 8003 with Dirac. I may be fooling myself that Dirac will manage speaker / sub alignment. I care more about this being right, so an acoustical timing will have to use crossover to get sound to subs. My earlier efforts show that I was getting some bass out of the speaker providing the timing (the selected as unplugged). The speakers are bi-amp so I could disconnect the bass on the timing speaker (only thought of that recently). Would this be better than the trial and error above (I do think I can start close, the 4-5 ms difference seems consistent).

Dirac has a good reputation so that would seem to be the best option. Just let Dirac handle the setup. If the measured SPL result is reasonable that is the most important factor. If you want to prealign the 2 subs using the miniDSP before the automated setup then just use the difference in distances of the 2 SWs to the LP position to calculate the delay timing needed for the closer sub (1ms for each 13.5"). If the final timing is within ±1 ms of the ideal timing that is close enough to avoid any significant impact to the SPL due to timing error.

 

[JStewart]

I have a NAD C658 playing thru 7.1 inputs of a Marantz 8003 with Dirac. I may be fooling myself that Dirac will manage speaker / sub alignment. I care more about this being right, so an acoustical timing will have to use crossover to get sound to subs. My earlier efforts show that I was getting some bass out of the speaker providing the timing (the selected as unplugged). The speakers are bi-amp so I could disconnect the bass on the timing speaker (only thought of that recently).

Hmmm...
Does the C658 Dirac implementation correct right and left channels only or right/left and sub channel separately?
Does the C658 implement bass management with high and low pass filters at the crossover or is there just a low pass filter for the sub out?

 

[Gregory Livingstone]

Generally; The phase transition near 20 Hz is due to normal phase rotation and can be ignored. A phase transition near the XO frequency is also expected with an ideal setup. It would also be due to normal phase rotation. Others in the bass range are either interference due to SW timing or to the room setup. It is common to have one or 2 of these in typical setups.
Sound arrival timing to the LP position from the 2 subs should be reasonably close to each other to avoid unnecessary SPL dips. The room setup may cause other dips in the SPL. Those are due to room dimensions and locations of the SWs and LP .

Depending on the situation, that DIY approach is a reasonable one, but what is the limitation of the Dirac automated setup capability that requires the MIniDSP and manual setup steps? I may not be much help as I have no experience with Dirac capabilities or limitations.

REW can play a sweep from a file as explained in the link that JStewart posted.

Dirac has a good reputation so that would seem to be the best option. Just let Dirac handle the setup. If the measured SPL result is reasonable that is the most important factor. If you want to prealign the 2 subs using the miniDSP before the automated setup then just use the difference in distances of the 2 SWs to the LP position to calculate the delay timing needed for the closer sub (1ms for each 13.5"). If the final timing is within ±1 ms of the ideal timing that is close enough to avoid any significant impact to the SPL due to timing error.

Thank you for the phase insight! Interpretation of measurements is hard to come by. Much appreciated.

I tried the physical measurement and my idea to add 4-5 ms to alignment tool generated curve. The latter approach worked, though I also did many measurements so it still ended up being more time consuming. The better approach would be using acoustical timing reference measurements, then use alignment tool and trace arithmetic to identify specific settings. This rules out the 2x4HD USB input in this case 1) for what you noted that USB mic requires acoustical reference 2) most subs are not able to play high frequency reference (I didn't even try so that is conjecture).

I got the subs dialed in using 2x4HD USB input. I switched input to analog thru NAD. I was dismayed by what I saw. Big dip at 67 hz. I had earlier replaced the Y cable I was using after earlier measurements. This 67 hz has been a bugaboo since February so I eventually realized the laptop port was broken. On another computer I had USB sound card dongle which I used on laptop. Now I got a FR that matched what I saw when using the 2x4HD USB, except for the phasing. The xover is set to 200hz (max on NAD). I don't understand why playing thru NAD xover does this or if I need redo the sub dial in. Advice?

At this point, I realize that I can get a clean sub only bass in the measure thru NAD, so it would have been possible to do all with acoustical references. From my experience, I trust that I can get a FR that was derived using the alignment tool! That's the good. The bad is my last speaker placement was made with faulty laptop port.

At this point, I will make acoustical measurements of subs separately w/o delay thru NAD with xover at 200hz, both speakers as out put but with one unconnected and the other with bass unconnected, so I can still get reference w/o bass. Suspect, I'll see if speaker placement can help with dip at 117Hz. Then I need to run Dirac and on the Marantz Audyessey.

I wish I could get more output between 25-40 Hz, but thinking its a sealed sub + room issue. Suppose that is another thread.

Attachments:

1. Physical measurement > 5.8 ms delay (didn't like dip) 2x4HD USB source
2. Alignment tool chosen curve 9.8 ms delay, but had to add 4-5 ms (lucky I saw a pattern) 2x4HD USB source
3. Source changed to Laptop port thru NAD input with XO at 200hz, speaker bass disabled
4. Source changed to USB soundcard dongle
5. Subs and Speakers thru NAD no Dirac

 

[Gregory Livingstone]

Hmmm...
Does the C658 Dirac implementation correct right and left channels only or right/left and sub channel separately?
Does the C658 implement bass management with high and low pass filters at the crossover or is there just a low pass filter for the sub out?

I think Dirac would measure each channel L, R, Sub1 and Sub2 if I had it connected that way, but as is its L, R, Subs on mine. What it does in the correction is less clear. During filter generation it can display corrected target curve which doesn't reflect what I expect if a XO was in play. It also squiggles as though it thinks it will get there.

I haven't measured NAD with sub enabled but subs turned off so don't know for sure.

 

[jtalden]

Gregory,
Chart 1 suggests SW1 is about 6.5 feet closer than SW2 so you added a 5.8 ms delay to SW1, but the SPL and phase results do not look favorable. That may be the room influence, but to really understand the reason we would need to have 3 measurements; SW1, SW2 (each separately) and SW1+SW2 (both together). Chart 2 at 14.3 ms looks much better and that may be as good as you will find. It is not unusual to sometimes see a better SPL and phase result with some timing mismatch. The extra 8.5 ms is okay, but I usually try to stay closer to the target timing.
The poor looking phase of charts 3-5 may just be due to the impulse location being shifted away from 0 ms. I would need to see the mdat of those measurements to tell. You can move the impulses near 0 ms in REW and check it out yourself.

Thinking again about loopback timing:
You now have acoustic timing working properly with the NAD to 8003 setup? All is good then. No need to use loopback timing. However in case you still haven't gotten repeatable results using acoustic timing setup we could check out using loopback timing again using the MiniDSP as you did before.
I'm understanding now your music setup path is direct from the NAD to the 8003. The MiniDSP is was used instead of the NAD to allow loopback timing as that was apparently not possible within the NAD. I'm thinking now this MiniDSP setup may work well enough for SW1 to SW2 timing adjustment, but I have no USB mic to experiment with. The error may not be a significant for this task of SW alignment.

If you want or need to find out:
Note the current delay setting for SW1 and SW2 in case we want to use this data for timing adjustment. Measure SW1, SW2, SW1, SW2, SW1, SW2, SW1, SW2, SW1, SW2. That is alternately measuring each SW in that order so we have 5 measurements of each SW. We can then see the scatter in timing error that results. I would pause at least a few seconds between each measurement, but just switching the active SW to be measured may be adequate time. Post the mdat here. You may need to split it into 2 files to post it here due to file size limitations. These results should give us a good idea if the error is significant or not. Others here

Note regarding XO timing confirmation:
There is an alternate method to determine the SWs to mains XO timing. So we don't need to get either acoustic or loopback timing working if they are a problem. If Dirac does this job we can confirm the timing if it looks to be a problem.

 

[Gregory Livingstone]

Gregory,
Chart 1 suggests SW1 is about 6.5 feet closer than SW2 so you added a 5.8 ms delay to SW1, but the SPL and phase results do not look favorable. That may be the room influence, but to really understand the reason we would need to have 3 measurements; SW1, SW2 (each separately) and SW1+SW2 (both together). Chart 2 at 14.3 ms looks much better and that may be as good as you will find. It is not unusual to sometimes see a better SPL and phase result with some timing mismatch. The extra 8.5 ms is okay, but I usually try to stay closer to the target timing.
The poor looking phase of charts 3-5 may just be due to the impulse location being shifted away from 0 ms. I would need to see the mdat of those measurements to tell. You can move the impulses near 0 ms in REW and check it out yourself.

Thinking again about loopback timing:
You now have acoustic timing working properly with the NAD to 8003 setup? All is good then. No need to use loopback timing. However in case you still haven't gotten repeatable results using acoustic timing setup we could check out using loopback timing again using the MiniDSP as you did before.
I'm understanding now your music setup path is direct from the NAD to the 8003. The MiniDSP is was used instead of the NAD to allow loopback timing as that was apparently not possible within the NAD. I'm thinking now this MiniDSP setup may work well enough for SW1 to SW2 timing adjustment, but I have no USB mic to experiment with. The error may not be a significant for this task of SW alignment.

If you want or need to find out:
Note the current delay setting for SW1 and SW2 in case we want to use this data for timing adjustment. Measure SW1, SW2, SW1, SW2, SW1, SW2, SW1, SW2, SW1, SW2. That is alternately measuring each SW in that order so we have 5 measurements of each SW. We can then see the scatter in timing error that results. I would pause at least a few seconds between each measurement, but just switching the active SW to be measured may be adequate time. Post the mdat here. You may need to split it into 2 files to post it here due to file size limitations. These results should give us a good idea if the error is significant or not. Others here

Note regarding XO timing confirmation:
There is an alternate method to determine the SWs to mains XO timing. So we don't need to get either acoustic or loopback timing working if they are a problem. If Dirac does this job we can confirm the timing if it looks to be a problem.

After looking at the measurements with acoustical timings, my estimate of difference is wrong. The front left sub is further away than the right rear. Delta of the delay = 4.328 ms. In the alignment tool that looks pretty good.

Yesterday afternoon, I redid speaker placement with USB SC on laptop. After that made some effort to check sub alignment thru NAD. First start I had left XO at 110. Realized that and set to XO 200 and made measurements. I looked at polarity change (the new impulses suggested they started different directions). I make the assumption that the little REF pointer indicates the peak to pay attention to.

Then I went back to delay of closer RR sub. In AT held > till curve looked good ending at 5.05 ms. Did trace math. Then I set MiniDSP and measured. It had a dip at 58.9 Hz which shook my conviction I understood the tool. It was getting late and wanted to use system that evening, so I set delay back to 14.32 ms. Ran measure to check. As an aside checked several XOs and settled on 90 Hz.

At this point I think using the acoustical timing is better as it helps make the Impulse chart more useful. I don't think multiple alternating sub measurements are needed.

Attached the mdat with just subs from yesterday. It has 5.05 ms actual measure as well as the individual subs. There is also what the AT predicted. I don't know what you would check, but would like to know the how and results.

Next I was going to redo the Dirac configuration and then do some listening.

I do expect to spend more time in tool. If I correctly assess impulse chart then, I think inverting a sub is called for. If there is a way to use a smaller delay, I'm game to give it a try in a day or two.

This has helped me to learn a lot and gain confidence in using REW. Thank you Jtalden!

 

[jtalden]

Measurement 11 looks favorable. It is basically the same as The calculated Measurement 9. I also used the alignment tool on measurements 6 and 7 as you did. I chose a delay adjustment of 6 ms. That is basically the same as the 5.05 ms answer that you found. My result is shown below as measurement 14. The real/actual timing of all 3 of these measurements is basically the same timing within maybe 1.5 ms of each other. I don't know why your setting change of 14.32 ms in measurement 11 was needed to provide an actual timing change of about maybe 4.5ms. [estimated value for scale - as I did not record the number I found and promptly forgot what it was]. No matter the reason the timing you set for Measurement 11 is favorable and nearly the same as we targeted with the tool. You are indeed ready for the Dirac setup.

FYI, below is the SPL, phase and impulse charts of Measurements 9, 11 and 14. I adjusted the impulse locations as needed to near 0 ms and such that the similar impulse shape and phase rotation of the 3 measurements can be seen.

 

[Gregory Livingstone]

Measurement 11 looks favorable. It is basically the same as The calculated Measurement 9. I also used the alignment tool on measurements 6 and 7 as you did. I chose a delay adjustment of 6 ms. That is basically the same as the 5.05 ms answer that you found. My result is shown below as measurement 14. The real/actual timing of all 3 of these measurements is basically the same timing within maybe 1.5 ms of each other. I don't know why your setting change of 14.32 ms in measurement 11 was needed to provide an actual timing change of about maybe 4.5ms. [estimated value for scale - as I did not record the number I found and promptly forgot what it was]. No matter the reason the timing you set for Measurement 11 is favorable and nearly the same as we targeted with the tool. You are indeed ready for the Dirac setup.

FYI, below is the SPL, phase and impulse charts of Measurements 9, 11 and 14. I adjusted the impulse locations as needed to near 0 ms and such that the similar impulse shape and phase rotation of the 3 measurements can be seen.
View attachment 30655

View attachment 30656

View attachment 30657

I think I duplicated what you did to get the overlay charts. I went to Impulse chart>Estimate IR delay>Shift IR. That lined up the major impulse peaks except the 14.32 ms one was bit to left. For 14.32 impulse chart used the Offset t=0 to set a -07 ms delay Which got peaks more or less lined up.

Will have to figure out the why of it. I get the value of doing it for comparison (similarity in this case).

I cannot out how you reduce the the legend to the 3 measurements. Thinking if the measurement number is preset so must be the other measurements. How do you manipulate the legend?

Post Dirac EQ, I see more lower bass on familiar songs using Spectroid app on tablet. Looking better. I'll do a proper measurement soon and while the gear is out test other lower RR delays.

The rear sub driver and MLP do not have line of sight as the chair back is high. Would something like that cause a dip like one measured for 5.05 ms actual? Based on your earlier reply I'm thinking I should try multiple measures to rule a fluke.

 

[jtalden]

I cannot out how you reduce the the legend to the 3 measurements. Thinking if the measurement number is preset so must be the other measurements. How do you manipulate the legend?

A save operation of a overlay chart only shows the measurements currently selected in the legend.

The rear sub driver and MLP do not have line of sight as the chair back is high. Would something like that cause a dip like one measured for 5.05 ms actual?

I wouldn't expect it to. A 60 Hz wavefront should not be disrupted significantly by a chair. The mic should be placed in direct sight of the main speakers for measuring, but the SWs should not be too critical of this. The only way to be sure in your situation is to try it.

 

[Gregory Livingstone]

FWIW, with EQ. I'm happy with the 20-50Hz improvement, think 50-80 degradation is bass mixing below 90Hz crossover. I consider adding the MiniDSP a significant improvement.

The Dirac target is a slope +3dB @ 20Hz to -3dB at 20K Hz. The House boost lower bass further and aligns with Dirac at 80Hz.

The other chart is a snip of Dirac app before generating new Dirac target filter.

 

[Gregory Livingstone]

I also did a set of sub only measurements. The ones the alignment tool say good, measure poorly in my room. I went to previous sub data and used the AT at 14.32 ms, which is quite different. Started thinking offset and found 7.08 ms looked about right. The third chart has a measures of 4.33 and 5.32 with offset added.

Wondered if MiniDSP was faulty and did some RR sub solo measurements and calculated delays. It isn't perfect, but delay offset close enough.

I'll keep working on it as a curiosity, but I'm happy with current results. Think I'll get more out of learning what a smooth FR is and understanding impulse.

 

[jtalden]

The alignment tool will always correctly predict the actual measurement result when the changes are properly applied. There is a problem with your process if that is not the case. If you find that the acoustic timed measurements are not repeatable for impulse location when repeatedly measuring a SW that is at least part of the problem. The overlay impulse chart should show all the repeated measurements on top of each other.

 

[Gregory Livingstone]

I did do double measurements on some of the attempts. The overlay charts attached. The 5.32ms one has most deviation. Is it enough to indicate measurement process issue?

These were back to back. When change Minidsp, I just change the delay value in GUI. The mic is on a studio tripod. The REW configuration is same. I am physically sitting by wall in front of RR sub by 3 feet and that is 2.5-3 feet from mic.

There are variance in reported delays as well:
For 6.69 ms:
Delay 7.3223 ms (2.512 m, 8 ft 2.9 in)
using IR start time relative to Acoustic reference on SPEAKER L with no timing offset
Delay 7.3250 ms (2.512 m, 8 ft 2.9 in)
using IR start time relative to Acoustic reference on SPEAKER L with no timing offset

For 6.0 ms:
Delay 7.3217 ms (2.511 m, 8 ft 2.9 in)
using IR start time relative to Acoustic reference on SPEAKER L with no timing offset
Delay 7.6680 ms (2.630 m, 8 ft 7.5 in)
using IR start time relative to Acoustic reference on SPEAKER L with no timing offset

For 5.32 ms:
Delay 7.3201 ms (2.511 m, 8 ft 2.9 in)
using IR start time relative to Acoustic reference on SPEAKER L with no timing offset
Delay 7.6588 ms (2.627 m, 8 ft 7.4 in)
using IR start time relative to Acoustic reference on SPEAKER L with no timing offset

I realize that perhaps need to repeat more for a better sampling. Does this small sample indicate process problem or suggest what it might be?

 

[jtalden]

Yes, that looks repeatable. The pairs overlay each other. The reduction in delay of the 3 sets of measurements is reflected in the proper shift of the each toward 0 ms. It would have been more clear to have zoomed in much closer so we could better see the offset change was accurately made, but this was good enough to confirm the acoustic timing is working properly.

I don't pay attention to the reported delay in the REW measurement notes. It is difficult for REW to pick an accurate delay based on the SW impulse shape. That value probably has its uses in other methods, but it is not directly involved with this process of using the alignment tool to make adjustments. We just find a favorable change of delay within the tool and then enter that change into a MiniDSP/AVR/music server or whatever vehicle we are we are using for delays. If the delay was already set at 5 ms during the SW measurement and the tool finds a change of +1 ms is more favorable then we set 6 ms as the new delay in the hardware. We would have to reduce the value is we are setting AVR distances as reducing the distance is increasing the time delay in the AVR. A new measurement will then reflect that delay change just as you demonstrated in these 3 set of measurements.

Other general DIY notes:

• Step 1 is to adjust the SWs timing to find a favorable timing for the groups. Step 2 is then to adjust XO timing so the SWgroup hands off properly to the mains
• We need to be careful not to accidentally shift the other more distant SW (Step1) or the mains (Step 2) in the tool as that just complicates calculating the changes to be made.

 

[Gregory Livingstone]

I decided to measure the subs with the Marantz. Installed ASIOALL. I made multiple measurements to see if there was variation. There was. Attached .mdat of subs individually. Another oddity I don't understand is the impulse peak being in negative time. Is this usable at all?

LF Sub (1,4,5) similar and (2,3) similar but different than first group.
RR Sub (6,8,9,10) similar and (7) is different.

Also, unexpected is using the alignment tool with (1,6), I get suggested FR curves that align with my measurements at least for the 5.05 amd 14.32 ones.

I admit to not disabling WLAN, Anti-virus. Are the impulse measurements differences likely caused by computer issues?

I figured that using 7.1 inputs skipped all processing (EQ, timing/distance). When I saw this thought perhaps timing/distance is still used. Can the negative timing of the peaks be caused by this?

To measure the sub(s), I ran output to L & R speakers (get less output with just one), which were unconnected. Sent timing reference to RSurr, Set LPF/HPF to 160 Hz. I don't see a way to disable the distances/timing short of zeroing them in manual speaker setup. Should I be doing that?

Could you expand on the DIY Step 2 about adjusting timing though XO?

In the impulse charts for LF sub in attached, the peak is south. The AVR also suggests the sub(s) are reversed in auto configuration. With AT inverting either sub lowers low end output though also lowers the 47 hz on part with 50-100 hz output. Would you sacrifice output for what might be smoother more typical sealed sub response?

 

[jtalden]

I don't understand is the impulse peak being in negative time. Is this usable at all?

This is no problem. The impulse location can be shifted away from zero either direction a result of the reference speaker sound arriving before or after the sound from the measurement speaker. If the reference and measurement speaker distances are the same then the impulse will be very near 0 ms. A small shift like we saw here is not an issue. We can use the REW 'timing offset' option in the measure panel to automatically plot the measurements nearer 0 ms if necessary for easy analysis.

LF Sub (1,4,5) similar and (2,3) similar but different than first group.
RR Sub (6,8,9,10) similar and (7) is different.

The 2 groups in each speaker set are shifted about 10 ms from each other. That is a significant difference even for bass frequencies and explains why we did not get the predicted result when we set the alignment tool delay change into the hardware and remeasured..

Also, unexpected is using the alignment tool with (1,6), I get suggested FR curves that align with my measurements at least for the 5.05 amd 14.32 ones.

I did the alignment tool on 1,6 also and found an increased delay of the RR SW by 13 ms provides a good alignment. We just can't be sure if the relative timing between SW measurement is correct however. We must have repeatable measurement results to get accurate predictions from the tool.

I admit to not disabling WLAN, Anti-virus. Are the impulse measurements differences likely caused by computer issues?

It normally isn't necessary to disable those. Some computers may benefit however.

I figured that using 7.1 inputs skipped all processing (EQ, timing/distance). When I saw this thought perhaps timing/distance is still used. Can the negative timing of the peaks be caused by this?

I also think that 7.1 inputs are a pass through. Even if they weren't the delay would be consistent; not changing from measurement to measurement.

To measure the sub(s), I ran output to L & R speakers (get less output with just one), which were unconnected. Sent timing reference to RSurr, Set LPF/HPF to 160 Hz. I don't see a way to disable the distances/timing short of zeroing them in manual speaker setup. Should I be doing that?

The settings you used are good for SW alignment. There is no need to zero the distances/timing as the changes we find in the REW alignment tool are just offsets from whatever those settings were.

Could you expand on the DIY Step 2 about adjusting timing though XO?

I just wanted to emphasize that these are 2 distinct steps in a DIY setup. Creating a favorable SWgroup needs to be finalized before moving on to XO timing. The measurements needed for XO timing is also a little more restrictive. In your case, just let Audyssey do the setup for XO, distances and EQ. Make sure Audyssey sets the L, R mains to small and check that the SPL is reasonably smooth in the XO range. If it is not, It may be worth following the step 2 process to confirm that Audyssey did indeed find a favorable XO delay setting.

The AVR also suggests the sub(s) are reversed in auto configuration. With AT inverting either sub lowers low end output though also lowers the 47 hz on part with 50-100 hz output.

If the SPL is not favorable with the initial SW polarity, I would run Audyssey with the SWs reversed if it allows that. Check each setup for SPL smoothness and extension. Make adjustments to the SWgroup distance/timing as needed based on the alignment tool. The correct polarity for SWs is the one that provides the smoothest SPL and if it is a tradeoff of bass extension vs smoothness in the XO range I would favor the latter.

Would you sacrifice output for what might be smoother more typical sealed sub response?

Loaded question. I have no issue at all running either ported or sealed. Use either one that provides acceptable smoothness in your room and hopefully reaches to the desired extension target.

I have no good thoughts as to why the acoustic timing is not working normally. I did note that the reference signal is set lower than the measurement signal, but at -30 dB or so it should have been fine. I think REW will warn us if it gets too low. If you are easily hearing the timing chirp before measurement sweep then all is well in that regard.

 

[Gregory Livingstone]

Thanks for this input.

My Marantz 8003 processor is older and the Audyssey thinking of time follows THX thinking of time, mainly to set speakers large if the meet criteria. I end up setting them small in manual setup afterwards. It may have individual XO for speakers, but I can only change the HPF/LPF 60 - 160 (or 180) hz. When I did the most recent measurements I thought 120hz was best.

I don't think there is unique Audyssey delay setting for XO, so I think you mean the distance settings and gather I would only adjust the sub's setting. If I'm confused about that please let me know.

On measurements, I did recently, attached SPL and Phase for comparable measures at XO 80, 100, 120. Reject 80 as get two dips. Chose 120 as dip is to right of 100 and slightly less deep. I'm guessing the possible timing issue is the phase transition over 70-100hz & the one 100-120. If I tweaked sub distance would the goal be making the two transitions one? Or do I look for something else.

Given, can't explain what gets wacky inconsistent timing, I'm thinking if I do multiple measurements and can say a majority are the same, that I could go with those for purposes of using the AT. Then of course measure to confirm. Following that reasoning, I'm looking at FR, Phase to have clearest "N" like shape avoiding narrow band transitions (distance between vertical lines) to find target delays to try. Might look to waterfall if all else is close to see which is less bloated. For instance 13 ms or 14.32 ms look very similar to me for FR & phase.

My plan (hope to do in/over next several days):

• Reset subs to factory default and then set volume / gain to -18 matching today (clear any lurking phase changes I made previously)
• Measure at higher volume ~ 90dB
• Measure each sub individually through Marantz (R&L disconnected XO at highest setting 160) with acoustical timing using surround though could be center which might be better. Do each sub 5 times. If still see variance repeat alternating the sub measured (more time between measurements).
• Using most consistent repeating results sample from each sub try the AT tool at 14.32 and 13 ms. Compare to existing measurements, Think will see same and will thus set the delay of rear sub to what I think is best. Otherwise if new measurements result use AT to find what delay should be.
• Make at least 5 combined sub measurements expecting consistency
• Do a single step auto configuration. If sub channel is reversed use MiniDSP to invert both subs, repeat single step auto conf. If normal sub leave that way though might also repeat combined sub measure to confirm same FR and phase.
• Set Marantz EQ off, turn Minidsp input channel off or both outputs, connect each main speakers, then by selecting each in the measurement set up get 3-5 measures of each main speaker by alone. The make 5 measures with both L&R enabled, sub off.
• Enable the sub channel in MiniDSP and make 5 measures of mains and subs. Check results though unsure what I would do if I see variance. Want to make sure I have data from same time.
• Switch to measuring NAD w/Dirac disabled, using ASIOALL instead of Java but do switch USB sound card dongle. Measure with NAD XO at 200 (off) and then 70-120. For where I think I will set the XO make 5 measurements to check for variance.
• Do Marantz full auto-config.
• Do Dirac config on NAD (same mic attachment boom mount)
• Measure NAD EQ (3-5X for 3 main filters I do)
• Measure Marantz, set mains small and determine best XO. Make 3-5 measures
• Here I think I have solid baseline of normal critical measurements with possible signs of variance or evidence of repeatable measurements.
• I don't know if I'll understand whether I have a XO timing that could be improved at this point. Bit if I do, presume I'd do that post Marantz auto config.

I already know I am getting improved bass response for movies (deeper more impact). For music (NAD) I can see some music has bass in 30-60 hz in Spectroid app that was missing. Given the bass measure well using Dirac filter in REW, I'm convinced that musicians rarely play lower bass notes loud. Notes in 70-120 hz are loud but not the 30-70. The MiniDSP is an improvement.

 

[jtalden]

It may have individual XO for speakers, but I can only change the HPF/LPF 60 - 160 (or 180) hz.

I don't think there is unique Audyssey delay setting for XO, so I think you mean the distance settings and gather I would only adjust the sub's setting. If I'm confused about that please let me know. Audyssey may turn off if you go to the manual settings and change the XO from 80 Hz or whatever Audyssey chose.

I'm was confused in referencing Audyssey in Post-20. I lost track of your setup. The Marantz is just a 7.1 pass through as you said so there will be no setup of any kind needed there. I should have said that the NAD Dirac setup is ready to run to set XO, timing and EQ. I assume it will take care of all that in the automated setup, but I never used Dirac so I don't know its capabilities or limitations. I only hear good things about it.

On measurements, I did recently, attached SPL and Phase for comparable measures at XO 80, 100, 120. Reject 80 as get two dips. Chose 120 as dip is to right of 100 and slightly less deep. I'm guessing the possible timing issue is the phase transition over 70-100hz & the one 100-120. If I tweaked sub distance would the goal be making the two transitions one? Or do I look for something else.

Choosing an XO frequency can get complicated. I tend to look at L+R vs SWs SPL measurements (taken full-range with no XO) and try to find a frequency where there are minimal dips in either SPL response. Often this is difficult to find. If Dirac will chose that for you when run that may be the best option.

Given, can't explain what gets wacky inconsistent timing, I'm thinking if I do multiple measurements and can say a majority are the same, that I could go with those for purposes of using the AT. Then of course measure to confirm. Following that reasoning, I'm looking at FR, Phase to have clearest "N" like shape avoiding narrow band transitions (distance between vertical lines) to find target delays to try. Might look to waterfall if all else is close to see which is less bloated. For instance 13 ms or 14.32 ms look very similar to me for FR & phase.

My plan (hope to do in/over next several days):

• Reset subs to factory default and then set volume / gain to -18 matching today (clear any lurking phase changes I made previously)
• Measure at higher volume ~ 90dB
• Measure each sub individually through Marantz (R&L disconnected XO at highest setting 160) with acoustical timing using surround though could be center which might be better. Do each sub 5 times. If still see variance repeat alternating the sub measured (more time between measurements).
• Using most consistent repeating results sample from each sub try the AT tool at 14.32 and 13 ms. Compare to existing measurements, Think will see same and will thus set the delay of rear sub to what I think is best. Otherwise if new measurements result use AT to find what delay should be.
• Make at least 5 combined sub measurements expecting consistency
• Do a single step auto configuration. If sub channel is reversed use MiniDSP to invert both subs, repeat single step auto conf. If normal sub leave that way though might also repeat combined sub measure to confirm same FR and phase.
• Set Marantz EQ off, turn Minidsp input channel off or both outputs, connect each main speakers, then by selecting each in the measurement set up get 3-5 measures of each main speaker by alone. The make 5 measures with both L&R enabled, sub off.
• Enable the sub channel in MiniDSP and make 5 measures of mains and subs. Check results though unsure what I would do if I see variance. Want to make sure I have data from same time.
• Switch to measuring NAD w/Dirac disabled, using ASIOALL instead of Java but do switch USB sound card dongle. Measure with NAD XO at 200 (off) and then 70-120. For where I think I will set the XO make 5 measurements to check for variance.
• Do Marantz full auto-config.
• Do Dirac config on NAD (same mic attachment boom mount)
• Measure NAD EQ (3-5X for 3 main filters I do)
• Measure Marantz, set mains small and determine best XO. Make 3-5 measures
• Here I think I have solid baseline of normal critical measurements with possible signs of variance or evidence of repeatable measurements.
• I don't know if I'll understand whether I have a XO timing that could be improved at this point. Bit if I do, presume I'd do that post Marantz auto config.

I already know I am getting improved bass response for movies (deeper more impact). For music (NAD) I can see some music has bass in 30-60 hz in Spectroid app that was missing. Given the bass measure well using Dirac filter in REW, I'm convinced that musicians rarely play lower bass notes loud. Notes in 70-120 hz are loud but not the 30-70. The MiniDSP is an improvement.

I am not really following the process here. My understanding is that you identified a delay setting for the MiniDSP that resulted in the most favorable timing as shown in Post-11. Just use that setting in the MiniDSP. That is all that is needed. Dirac will handle the rest. If the SPL result is smooth through the XO range you are done. If there appears to be an SPL issue there it may, or may not, be related to SW group timing. If you have a concern about the SPL in XO range I can provide help to determine if it is a timing issue.

If you are still concerned about the acoustic timing issue there is not need to resolve that to complete this setup. I can confirm if the XO timing that Dirac sets is favorable without using acoustic timing. If your plan above is just to investigate further to better understand setup issues then enjoy the learning process.

 

[Gregory Livingstone]

I am not really following the process here. My understanding is that you identified a delay setting for the MiniDSP that resulted in the most favorable timing as shown in Post-11. Just use that setting in the MiniDSP. That is all that is needed. Dirac will handle the rest. If the SPL result is smooth through the XO range you are done. If there appears to be an SPL issue there it may, or may not, be related to SW group timing. If you have a concern about the SPL in XO range I can provide help to determine if it is a timing issue.

I was OK where I was, though still troubled by the timing variance. Also with various issues my old data was useless. I remembered someone in a forum suggesting that a sub's setting hadn't cleared when they undid a setting. Wondered if that was my problem. Also, given that ASIO4ALL was on my system, thought a new baseline with that was appropriate.

Before doing anything I rotated the subs FL facing rear, RR facing front. Earlier measure they faced opposite side. with faulty measures that seemed a bit better. I was confident I'd be able to use the AT to get similar curve.

Resetting the subs to factory default fixed the repeatable measurement issue! I made 5 measures of each sub w/o delays using the center speaker for reference. For each sub all 5 were same FR, Phase, Impulse (used overlay tool to quickly check). Also the timings were positive. Used AT tool to identify a number of reasonable RR sub delays. Then measured those. All essentially matched AT. I made all AT tries with 1 FL and 6 RR. At end I settled on RR delay of 13.1 ms. Now I can say I know how to use AT

I went on to check subs against speakers and look for XO for both Marantz and NAD. Ran the Auto config Audyssey and Dirac on respective devices. In a day or two I'll use REW to see how things look.

FWIW, DIRAC doesn't set XO or rather if it does it is internal and unseen. The NAD lets you change XO or disable the sub. Remove the sub and Dirac deals with it.

I am really happy you were emphatic that the AT will produce target settings that would be validated by measurement. It kept me going. I fixed my issues I didn't know I had. And in the end I was able to use AT exactly as you said Can't thank you enough for your continued help and support

 

[jtalden]

Well done!