[Completed Beta] Automatic timing alignment for Main Speakers and Subwoofer

[slartibartfast]

Prior of this new update I get the same number no matter how many times I run it. Now it goes 1 then 8 then 1 then 8. It is important to check features when we get new update as may cause a problem from existing feature.

I bet both of those settings have phase cancellation at the crossover frequency anyway. It doesn't try to optimise the phase at the crossover.

 

[MrA]

The time alignment doesn't use the phone mic, it uses the mic in the device.

Yes, I saw that previously but that introduces a major flaw in the process - full time coherence needs to happen where the listener sits so all frequencies regardless of source arrive 'to their ears' concurrently. Measuring from the location of the WiiM equipment means full time alignment only occurs at that position in the room & 'that' is where music will sound most correct....illogical unless that device is mounted at a point between their ears!

Sorry to hark on about this but I have been heavily into this process since 2012 and any study into the subject will always take the listening position as the point where subs and main speakers should converge correctly.

WiiM have it correctly when asking to place the main phone microphone in the listening position for room correction and this should also be the same for time alignment.

As an experiment would you be able to place your WiiM device against the headrest of your listening chair and measure from there? (assuming we know where this supposed microphone sits in the casing - I am still dubious that this exists as I haven't seen anything locating it and in any case accuracy would demand that the mic is not obscured by surfaces surrounding it which would also cause reflections to certain frequencies etc. Time alignment in its most basic form will process the initial peak of the highest subwoofer frequency against the initial peak of the main speaker tweeters. Those tweeter frequencies will be compromised unless the mic stands free from surrounding surfaces).

See the attached images of the professional mic that I use which is typical of any other types. The main pic was taken during 'anechoic' time alignment & calibration of the various individual drivers in my OB speakers, outdoors on a quiet dry day, elevated high above & away from any other surfaces to avoid reflections and as you see there are no other reflective surfaces at the recording tip of the mic. Subs were also frequency time aligned here and then all were time aligned together in the music room from the listening position.

 

[harkpabst]

Yes, I saw that previously but that introduces a major flaw in the process

Slarti didn't make this up or conclude this from his measurement experience: It's been confirmed by WiiM that automatic timing alignment uses the mic built into the WiiM device.

And yes, I agree that it doesn't make sense. So, it's not so much about this function not trying to optimise the phase at the crossover frequency. It's technically impossible using this approach.

 

[s3igell]

(assuming we know where this supposed microphone sits in the casing - I am still dubious that this exists as I haven't seen anything locating it

Look at page 9 of the WiiM Pro / Pro Plus pdf manual (back side between USB-C Power and SPDIF-In).
Look at page 5 of the WiiM Mini pdf manual (right of the SPDIF-Out - labeled "1 AMIC for AirPlay2 Sync")
Look at page 10 of the WiiM Amp pdf manual (back side between RCA Sub-Out and bottom-left Speaker Binding Post)
Look at page 11 of the WiiM Amp pdf manual (back side lower left of the RCA-Out Red)

In all models, the mic is recessed within the case accessed through a small hole (that too many "pundits" have advised in various threads is the "Reset Button").

 

[guy48065]

Might it be better if WiiM were to make it possible to do the RC & time alignment externally? Like what if you could export the data gathered by the frequency sweep into a 2nd party program, or REW, or something downloaded from WiiM.

 

[slartibartfast]

Might it be better if WiiM were to make it possible to do the RC & time alignment externally? Like what if you could export the data gathered by the frequency sweep into a 2nd party program, or REW, or something downloaded from WiiM.

How would that be better than just using REW to measure the response?

 

[guy48065]

Is REW available as an Android app?

 

[slartibartfast]

Is REW available as an Android app?

No

 

[MrA]

Look at page 9 of the WiiM Pro / Pro Plus pdf manual (back side between USB-C Power and SPDIF-In).
Look at page 5 of the WiiM Mini pdf manual (right of the SPDIF-Out - labeled "1 AMIC for AirPlay2 Sync")
Look at page 10 of the WiiM Amp pdf manual (back side between RCA Sub-Out and bottom-left Speaker Binding Post)
Look at page 11 of the WiiM Amp pdf manual (back side lower left of the RCA-Out Red)

In all models, the mic is recessed within the case accessed through a small hole (that too many "pundits" have advised in various threads is the "Reset Button").

So yes, all time alignment measurements using a very small recessed mic will also be compromised by the surrounding casing material and also by measuring in a room location likely to be unrelated to the actual listening position. Both must contribute inaccuracy to the alignment process.

 

[hgo58]

It is about alignment of signal processing delays, not about phase alignment. So the placement of the microphone don't matter as long as it can pick up all audio.

 

[jxrxme]

When can expect to see this feature on my WiiM Amp? Firmware is 5.0.636055 from 20241119 and WiiM Home App is 3.0.2.

 

[harkpabst]

It is about alignment of signal processing delays, not about phase alignment. So the placement of the microphone don't matter as long as it can pick up all audio.

With the microphone put in a random place, how should the algorithm be able to tell apart if the delay has been caused by internal processing or by the distance to each speaker, unless the distance is entered manually?

If the processing delay was vastly longer (like >150 ms) than that cause by speaker placement (usually <15ms), the latter might be safely ignore. But I don't think this is the order of precision we had hoped for.

 

[hgo58]

With the microphone put in a random place, how should the algorithm be able to tell apart if the delay has been caused by internal processing or by the distance to each speaker, unless the distance is entered manually?

If the processing delay was vastly longer (like >150 ms) than that cause by speaker placement (usually <15ms), the latter might be safely ignore. But I don't think this is the order of precision we had hoped for.

I think it is. If the difference in the distance between the WiiM, the Sub and individual speakers are less than these 5 meters (15ms) it should be fine.

 

[canard]

you cut with 48db?frequency cut? what type of music?

 

[MrA]

I think it is. If the difference in the distance between the WiiM, the Sub and individual speakers are less than these 5 meters (15ms) it should be fine.

I'm afraid not.

I have a lot of experience of this & as a temporary 'party trick' I once placed the mic at the door opening to my room & took time delay measurements from there. Standing in that doorway, realism & soundstage became almost as precise as the regular listening position.

However, seated in the normal listening chair the soundstage then became less focused and bass around the speaker/sub crossover point was significantly out of step with certain frequencies sounding overblown or hollow. This is a position less than 5' behind and to the right of the chair, yet at the doorway the crossover was undetectable (as would be expected).

Feel free free to disagree but the science behind room time correction dictates that perfect alignment only occurs at the measurement point, be that by distance calculations or more precisely by microphone.

 

[guy48065]

Seems common sense to me.
In my listening room the sub is very close to the WiiM mic. In my listening position the speakers are closer to my ears than the sub is, because they are pulled out away from the wall.
There's no way the time-alignment would be correct.

 

[Smartplug]

Well, it would be great if wiim would say something regarding everyone comment.

 

[slartibartfast]

Well, it would be great if wiim would say something regarding everyone comment.

This what they said previously
Post in thread '[Completed Beta] Automatic timing alignment for Main Speakers and Subwoofer' https://forum.wiimhome.com/threads/...r-main-speakers-and-subwoofer.5153/post-87535

 

[harkpabst]

I think it is. If the difference in the distance between the WiiM, the Sub and individual speakers are less than these 5 meters (15ms) it should be fine.

I have never seen a subwoofer where the delay claimed by the manufacturer was >10ms.

Delay in the region of hundreds off milliseconds is typically rather found in multi-room setups or with Bluetooth.

 

[hgo58]

Let us say the active sub has a delay of 5 ms and the speakers (though an external DAC and amp) has a delay of 25 ms. You then want to delay the sub out by 20 ms.

It would however be beneficial if WiiM defined the conditions for the auto measurements. I don't see that in the documentation, except maybe for the drawings?

Tutorial: Syncing Your Subwoofer with Main Speakers