Time Align Tool says the delay between Left speaker and subwoofer is +10ms. B -16ms for LR/Sub, but +10ms for L/Sub and R/Sub. Am I missing something?

[donka]

Yeeesh. Sorry about the mangled title y'all. Looks like I can't edit it either. Ah well.

I'm sure I'm misunderstanding something, but I would expect the delay between individual speakers and sub to be about the same as the combined speakers and sub. Here's what I did:

1. Took SPL measurements for L, R, L+R, and Sub.
2. Clicked Controls --> Alignment Tool
3. Selected "Sub" in the first drop-down, and "Left" in the second.
4. Placed cursor at the crossover point
5. Clicked "Align phase at cursor"
6. Repeated 3-5 for "Right", and "Left+Right"

Here were the results:

Speakers being compared	Subwoofer Delay (after clicking "Align phase at cursor")
L vs Subwoofer	10.35 ms
R vs Subwoofer	10.34 ms
L+R vs Subwoofer	-16.39 ms

I assume I should just go with the L+R measurement, but it's such an unexpected result that it makes me wonder if there's a deeper problem with how I'm using the tool.

 

[jtalden]

If you post the mdat file, I will take a look at it and advise.

 

[donka]

If you post the mdat file, I will take a look at it and advise.

Sorry about the delay! I can't seem to find the exact mdat that lets me reproduce the numbers above, but the same effect occurs with this mdat file (individual speakers produce a positive offset, combined L+R produce a negative).

Some relevant info:
1. I use a Denon AVR-X3500H with Audyssey to handle room equalization, crossovers, etc
2. This mdat was measured with the receiver in "Surround" mode
3. "SB-1000" is the sub. "Tekton L" and "Tekton R" are my fronts.
4. My Denon Receiver crosses the fronts over to subwoofer at 40Hz.

Let me know if you need any other info, or additional measurements. Thank you!

 

[jtalden]

Audyssey did a very good job of setting up your system.
The SPL chart and the phase chart are both smooth across the frequency range. If there was an issue related to speaker distance or EQ settings there would be deviations in the charts near the crossover frequency.

I suggest:

• Change the Denon XO for all speakers to 80 Hz as the Audyssey setting of 40 Hz is very low. This is a common recommendation. Most main speakers are being pushed too hard using a 40 Hz XO. It's possible to use a low frequency XO setting like 40 Hz only if your listening levels do not overburden the main speakers.
• Confirm that all 5 main speakers are set to 'small'.
• If you do change the crossover frequency to 60, 70, or 80 Hz or other frequency it is a good idea to repeat the measurements of the 5 main channels to assure the SPL is still smooth in the crossover range.

Comment:
Placing the cursor at 40 Hz, I confirmed your delay findings using 'Align phase at cursor'. The measurements provided here do not meet the requirements for using the REW alignment tool however so those delays are meaningless.