It's not measuring the physical distance, it's measuring the delay from the preamplifier thru the power amplifier and the speaker filters and then the speaker element and finally thru air to your mic. So it will always read a bit longer than the distance from speaker element to mic.

I don't know if that matters much. You'll need to have your head in a wise to not move it 1ft to either side or front to back. Someone needs to sedate you to immobilize you to make you sit that still. How do cinema theaters handle the delay times from speakers to make it sound good to a 500 person audience, if 1ft of difference in distance would have a major impact on the sound experience?

 

Without even asking how he’s routing the signal into the avr your making massive assumptions about the signal path being different between different speakers

For a distance measurement to be input and be accurate the latency though each channel should be roughly equal assuming all channels are internal amps… are you saying Denon don’t consider this and can’t set delays internally to adjust for this

everything should hit the central mic position at the exact same time, that is how audessey calculates distance and therefore timing within the system

 

I am running Audyssey on my Denon for my 11.1 system. But it looks like the impulse chart in REW is saying that the front LCRs (and 2 front subs) are 1ft (0.3m) further away than they should be. The 4 surrounds are closer to what I think should be zero, but are still about 6in (0.15m) away.

I am using the UMIK-1 mic in the seating position (with 90deg cal file), and setting the surround right as the acoustic reference (Ref in the image), which is the closest speaker to the mic.

I can go in and start tweaking the Denon distance params to get it zeo'ed, but I am very reluctant to do this.

View attachment 3274654

How did you insert the signals into the denon
7.1 hdmi via asio4all?

 

apologies duplicate post

 

Yeah if I wanted to start overriding Audyssey, those are some good tips for the process. But I would have to become 100% convinced its getting it wrong before I start trying to make changes, at which point you are ditching Audyssey since these measurements are tied into the core process. I mainly am just hoping get insight into why REW impulse is showing that they are off, if indeed they are.

 

I would expect the traces to be closer than that after autocalibration. My most recent one had the impulses within 200us of each other, so 2 inches.

Where's the "6 inches" you mention?

And are the reported measurements wrong by the tape measure?

Have you got any sort of upmixing or other functions enabled? It's possible the upmixer's doing something to delay the surround signal.

Those are the two most likely reasons for the offset - delay is actually set wrong (but why?), or some processing.

 

Where's the "6 inches" you mention?

I didn't have the surrounds selected in REW to make the image I shared easier to read.

And are the reported measurements wrong by the tape measure?

I just checked again. The measurements in the Denon setup are spot on, when measuring from the speakers to the 1st Audyssey mic position.

Have you got any sort of upmixing or other functions enabled? It's possible the upmixer's doing something to delay the surround signal.

No. It's a pretty simple setup. The signal path (for REW measuring) is laptop > hdmi > denon avr > speakers. When running Audyssey beforehand I am measuring in 3 positions, primary seating position at center width of room, then 2 more to the left and right about 16in (40cm) away.

I'll go through the laptop sound settings again with a fine tooth comb. This is a windows laptop, and it just occured to me I have a macbook I could test it with as well.

Those are the two most likely reasons for the offset - delay is actually set wrong (but why?), or some processing.

I guess maybe there is another type of REW measurement I could do where I play say the left speaker and the reference surround right speaker I was using at the same time, and check their phase alignment. Just need to learn how to that!

 

For clarity here is another run with all speakers showing. The black trace is the reference surround right.

Here are the generated note fields showing the delays. Again note how much closer to zero the Sur Left is (even though the reference was Sur Right). This might just be a coincidence though.

 

For clarity here is another run with all speakers showing. The black trace is the reference surround right.

View attachment 3275421

Here are the generated note fields showing the delays. Again note how much closer to zero the Sur Left is (even though the reference was Sur Right). This might just be a coincidence though.

The LCR speakers are aligned to within one inch, ≈ 77µs, or one wavelength at 13.558 kHz. If the resolution for the distance settings in your AVR is limited to .1 ft, 1.2 inches, then you are not going to get better timing then this through manual manipulation of the distance settings. Since the LCR speakers carry the most dialog/music information, the fact that the surrounds are 'off' by a foot, is immaterial. You're chasing diminishing returns with no discernible benefit.

 

Are any of your speakers dipole/bipole? That would explain it.

 

Nope. These are Triad Silver LCRs

 

For the 4 surrounds yes. The LCR's are in-room.

 

I don't know why it would be an issue using an in-wall speaker as a timing reference, but I would try to use the L, CC or R speaker instead just to see what results I got.

 

Yeah did that too. Results in the same 1ms difference between front and rear (just reversed). I even switched to a macbook and got the identical results. By all accounts REW is reporting correctly. Just need to process what this means.

 

I listened to Norah Jones reference CD, her first one, in stereo and changed the timing distance to the right speaker one, two and then three feet and all instruments stayed in their place and I moved my head +/- 1 ft to the sides and the only difference I could tell was that Norah's voice changed a little in the midrange but I couldn't tell if either setting gave the true sound as both sounded good to me. Then I changed to 5.1 and listened to the intro of the Doom movie that has some great surround effects. Changed right surround to have 1ft longer distance and couldn't hear any difference to the sounds that swoops from rear to front. How does those home cinema guys do with the distance settings when they have 3 seats besides each other, are only the middle one getting the proper sound bubble and the outer seats 3ft from the middle do not?

 

Yeah I think the issues are most relevant when it comes to lower frequencies and phase alignment of multiple subs, and also for the good LFE crossover performance. This is where most of my concern is at.

 

John over at avnirvana has convinced me REW is reporting correctly. So just need to convince myself now that Audyssey is ok as is.

Figured I would share this SPL-Frequency Response graph in case it meant something. For the Left speaker, it compares the default delays Audyssey set, to an adjustment I just made in the AVR to bring the Left delay into alignment to the reference Surround Right. The Left+SurRight is both speakers playing at the same time before the adjustment, and Left+SurRight (aligned) is after. I guess the notable thing is the general increased SPL of the aligned one.

Is my reasoning correct that if there were a phase issue between the two speakers due to a timing mismatch, the orange SPL line (before adjustment) would be suppressed, and the purple SPL (aligned) would in show the increased SPL as it shows?

I realize this test may not being testing what I think it is though.

 

My reference channel never comes at that close to 0 delay either - looking at my last set of measurements, the reference centre had "Delay -0.0163 ms (-5.6 mm, -0.22 in)".

Your results are certainly not as good as I'd expect given an Audyssey auto-calibration, a Denon receiver, and reported measurements that match your tape measure.

I would still expect everything to be within a couple of inches, not spread over nearly a foot. Mind you, that's with me having 7 identical speakers.

You say all the higher-level processing like Audyssey is off. What about bass management? Have you tried "Multi-channel direct" mode?

Phase issues are a bit unpredictable at higher-than-subwoofer frequencies, so summing test won't be totally clear.

You can test this interactively in the time alignment tool - "what would signals A and B sum to with a particular delay?" - dragging the delay slider - you don't need to make an actual measurement. That'll give you a feel for the effect, and you can seek the optimum delay by looking for the strongest low-frequency signal, dragging the slider. Testing it myself, the effects at 1ms aren't huge, but by 2ms they would be.

Another thing you could try, to try to figure out if it is the PC or the AVR generating the front/surround/rear difference:

Switch the PC's HDMI output to 2-channel, send the test sweep to left and reference to right.

Put the receiver into "all-speaker stereo" mode, so L -> L+Ls+Lrs+C, and R -> R+Rs+Rrs+C. (And ceilings? I'm still in 7.1-land).

Disconnect all speakers except L and R.

Then run the test - L does the sweep, R is the reference. Disconnect L and connect Ls to get the surround sweep, then do Lrs for the rear.

 

You can test this interactively in the time alignment tool - "what would signals A and B sum to with a particular delay?" - dragging the delay slider - you don't need to make an actual measurement. That'll give you a feel for the effect, and you can seek the optimum delay by looking for the strongest low-frequency signal, dragging the slider. Testing it myself, the effects at 1ms aren't huge, but by 2ms they would be.

Wow, thats an amazing tool! It's crazy how well it mirrors the actual measurement. One thing that is blowing my mind though. In my screenshot you can see the black prediction, with the 0.82ms delay added to align the speakers. How does the prediction know about those deep dips (nulls?) at 144Hz, 197Hz, etc? Those dips don't exist in the input signals (Left and Sur Right). I figured the dips were features of the room (the interaction of the combined speakers with the room), so how does the alignment tool know about them? Are the dips actually a feature of the two signals?

 

You may have tested to switch the + and - to one of the front L or R speakers and listen to a totally out of phase signal. You don't get a define placement of musical instrument or voices between the speakers, it's more floating inside your head but audio volume are more or less unaltered. At 1KHz a full wavelength are 1ft and if a signal are 1/2 wavelength out of phase in will be in the opposite phase. So 1ft difference in time delay at 500Hz will give an out of phase signal. Small differences in delay will move the dip in level where the phases are opposite to each other. Those dips at 150Hz and 200Hz in the graph might show the differences.

That long stretch of the purple curve with an increase of 6dB from 270Hz to 900Hz, with a dip in the middle, are something else as it goes thru several phase shifts over that frequency range. If you have a lab room with no reflections you would see phase issues more clearly but in a normal living room you got so many other reflections and standing waves that it doesn't matter much what you do. A Audyessey mic calibration can compensate for those level differences between the purple and orange curves.

Those dips at 200Hz and 150Hz are related to 3ft and 5ft distances, perhaps reflections to ceiling or floor.

 

Ah yep, I just turned on the phase traces option in that tool and it makes that much more obvious. Good stuff.

 

I am running Audyssey on my Denon for my 11.1 system. But it looks like the impulse chart in REW is saying that the front LCRs (and 2 front subs) are 1ft (0.3m) further away than they should be. The 4 surrounds are closer to what I think should be zero, but are still about 6in (0.15m) away.

I am using the UMIK-1 mic in the seating position (with 90deg cal file), and setting the surround right as the acoustic reference (Ref in the image), which is the closest speaker to the mic.

I can go in and start tweaking the Denon distance params to get it zeo'ed, but I am very reluctant to do this.

View attachment 3274654

I would not accept a 1ft / 1ms time alignment error in any of my systems, if it was correctable.

 

If you move your head 1/2ft to either side, then the difference between left and right surround will be 1ft/1mS. Are you measuring the delay from one golden position and will that be where you have your nose or to your left or right ear? I take it that your ears are almost 1ft from each other as a normal persons are.

 

Good news is yesterday I found a post on the Audyssey support desk where they officially say that tuning the delays will not effect the correction filter performance (ref). This was my major fear, fixing one issue and causing another.

Can I change the delay and trim levels found by MultEQ?

Yes, these can be changed manually if so desired. Doing so will not have any effect on the room correction filters that MultEQ creates. It will, however, impact the rendering of the soundstage and the blending of the subwoofer with the satellite speakers.

So I plan to manually align them all tonight and compare both in measurements and in listening.

 

I think you might be missing the point. The issue is if you know there is an error of this proportion at the same consistent measuring position, then something is wrong. What else might it be getting wrong, if indeed this is a bug? An avid hobbyist (like me) or professional would like to at the VERY least understand why. Fixing it would be even better. I agree with what you are saying in some respects, but not in others. What if its not applying the proper delays to my subs by 1ft? There is no debating about how bad that might be.

 

The issue is if you know there is an error of this proportion at the same consistent measuring position, then something is wrong. What if its not applying the proper delays to my subs by 1ft? There is no debating about how bad that might be.

...but also regardless a foot is a large amount for time alignment to be out

The measured differences in distance between different method used can be anything from how the guys did it that calibrated the mic to the app and how the calculations are done and probably lots of other things. But my point is, do we really need it to be that accurate, when our body position will be more inaccurate than the error in measurement?
At a subs frequencies one wavelenght will be 10ft and more and 1ft more or less should have absolutely no impact on the sound quality or air pressure from the subs. If you move 3ft to the side you probably change 1/2ft plus to one sub and 1/2ft minus to the other.

 

But you are missing out on the sweet spot. Do it!

 

Or get atmos speakers grafted in front and behind your ears and a sub inserted somewhere 😂

 

At frequencies < 300Hz or so you are no longer hearing the speakers directly, you are hearing the room. Here standing waves and the modes they create dominate, which is all dictated by room dimensions and wall construction. These good and bad areas of the room do not move, so it doesn't matter where you have your wiggly nominally sized head. But you can carefully place your seating, and multiple subwoofers to create a large sweet spot where you and others sit (which I have taken care to do). Bad phase alignment can work against that goal.

 

Bad phase alignment can work against that goal.

I agree. If you have a half wave length, 5ft, wrong in phase it would cancel out much of the direct signal, but 1ft? If it would cancel out 3dB theoretically at 2,5ft you might be able to hear it. The general opinion are that humans can barely hear a 3dB difference in sound volume. When you have several subs generating the exact same sound you will have multiple places in the room where their sound waves add and where they cancel each other out. It will only be phase correct at the mic position, if we disregard all reflections and standing waves. Have you done a A/B test with the calibrated values and then set all subs to 0mS to see what it does? It would be interesting to know. I'm gonna do that and see what the result might be. Some people say that running their AVR "naked" without the calibrated values produce the most pleasant sound to them.

edit: I had one sub at 4meters and the other at 2 meters and set both to 0 and could hear no difference. It could matter if you use a configuration where you run the sub frequencies to both the front speakers and the subs. But who in their right mind would do that.

 

Fair. I do think this thread has gone astray a bit though. We have devolved into debating psychoacoustics. Which is fine and interesting. But my OP was not about the specific values I am measuring, and their impact. I can fix that easily with some manual tuning. Its about whether I have found a bug, or an an unstated characteristic of Audyssey, Denon, etc. Clearly no one has noticed what I am pointing out in their own systems, which was the point of the thread. Moving on...

 

Clearly no one has noticed what I am pointing out in their own systems, which was the point of the thread. Moving on...[/QUOTE]To learn anything from this thread, what could the reason be, if you are alone seeing that difference, to help others not making the same mistake, or using the wrong software version or calibration file or whatever the issue might be? Everybody are stumped and have no explanation?

 

I always time align my subs. 0.5 ms is noticeable.

 

It will also affect the Haas precedence effect, which I think is the most-often cited reason for getting time alignment right. Having the fronts a millisecond early (or surrounds a millisecond late, depending on the way you look at it) will reduce ambience, and tend to pull things intended to phantom image to the sides towards the front.

So when talking about the phase effects of the delay, we're now actually two steps away from the point of the thread ("where is this measurement/output error coming from?"), cos that phase effect isn't even the primary problem of a real delay (assuming it is real).

@Easley - can you try my "2-channel input, all-speaker output" test? Or is it too much hassle? Of course, all-speaker output may have its own set of processing quirks to add more confusion. But it could rule out the PC having an output offset between its front and surround channels.

 

It will also affect the Haas precedence effect, which I think is the most-often cited reason for getting time alignment right. Having the fronts a millisecond early (or surrounds a millisecond late, depending on the way you look at it) will reduce ambience.

So when talking about the phase effects of the delay, we're now actually two steps away from the point of the thread ("where is this measurement/output error coming from?"), cos that phase effect isn't even the primary problem of a real delay (assuming it is real).

@Easley - can you try my "2-channel input, all-speaker output" test? Or is it too much hassle? Of course, all-speaker output may have its own set of processing quirks to add more confusion.

timing effects phase differences freq dependant, moreso the higher in frequency you get and that’s why we implement timing, it’s all the exact same thing and related

 

@Easley - as this is so mysterious, I still think there may be something we're missing (or not being told).

Can we have full details of what AVR and speakers you're using? I don't think you've revealed this yet.

It may also be helpful to actually show some screenshots of some of the config menus in the AVR, to see if anything's on that shouldn't be.

 

@Easley
Can we have full details of what AVR and speakers you're using? I don't think you've revealed this yet.

Its a Denon AVR-X6700H purchased in 2020. Running the latest firmware. Speakers are Triad Silvers (in-room for LCR, in-wall for 4 surrounds).

It may also be helpful to actually show some screenshots of some of the config menus in the AVR, to see if anything's on that shouldn't be.

Audio/Bass Sync
Bass Sync = 0ms

Audio/Surround Parameter
Cinema EQ = Off

Audio/Audio Delay
Auto Lip Sync = Off

Audio/Audyssey
MultEQ XT32 = Reference (tried this with both Flat and Off)
Dynamic EQ = Off (tried this with On)
Dynamic Volume = Off
Audyssey LFC = Off

Speakers/Amp Assign
Assign Mode = 11.1

Speakers/Speaker Config
Front = Small
Center = Small
Subwoofer = 2
Surround = Small
Surr Back = Small (2)
Top Front = Small
Top Read = Small

Speakers/Distances
(all in feet)
Front L = 12.1
Front R = 12.1
Center = 11.5
Sub 1 = 16.4
Sub 2 = 17.5
Surr L = 6.3
Surr R = 6.2
Surr Back L = 8.7
Surr Back R = 8.6

Speakers/Crossovers
All 80Hz

Speakers/Bass
Subwoofer Mode = LFE
LPF for LFE = 120Hz

 

Yeah I asked for clarification on what this affects. Recent Audyssey versions, only Denon's, etc. Will report back.

 

Huh... I wonder if this applies to Marantz since it's essentially the same company.