Speaker time alignment, does it matter?

[Andrew s]

Clearly a difficult issue to reach consensus. In choosing equipment I have followed a simple idea. Choose kit that has low distortions, flat frequency response across a wide bandwidth and is time aligned as far as possible. This seemed to me to be the best way to reproduce both harmonic and percussive sounds.

I may well not be able to hear differences from this ideal but why take an unnecessary risk if I can afford the kit?

Regards Andrew

 

[Snarfie]

I'm 62 an owned quite some speaker systems/brands most of them quality columm farfield speakers. Just some years ago i stumbled on pair of Vandersteen speakers i was first not impressed by them till i put them on the correct spot an tilted them as described in the manual. Till to day i did not hear a staging/Imaging as the Vandersteens deploye realy astounding. I notice that lots of professional musicians are owning Vandersteens.

Vandersteen brand is known by building specific time alignment/phase coherent speakers.

https://www.stereophile.com/content/musicians-audophiles-paul-wells

https://www.stereophile.com/content/musicians-audiophiles-billy-drummond

https://www.stereophile.com/content/musicians-audiophiles-john-escreet

 

[Rip City Dave]

Newb here. Are planar speakers like electrostatics or magneplanars inherently aligned in time?

 

[puppet]

As all the audio signals emanate from the same panel, then yes.

 

[FrantzM]

As all the audio signals emanate from the same panel, then yes.

This suppose one driver... If like some Magnepans, you have different drivers with crossovers and placed differently ... no.

 

[youngho]

Newb here. Are planar speakers like electrostatics or magneplanars inherently aligned in time?

No, not inherently. Unless they use a concentric ring design like the smaller Quad electrostatics (for example, see here: https://www.stereophile.com/content/quad-reference-esl-2805-loudspeaker-measurements versus here: https://www.stereophile.com/content/quad-esl-2912-loudspeaker-measurements), signal from different parts of the panel will arrive at your ear at different times, due to differences in path lengths from the parts of the plane that are further away from you.

[edit] I was thinking about time coincident

 

[Frgirard]

https://audioxpress.com/article/zero-phase-in-studio-monitors

 

[MrPeabody]

It would be better if this question were treated as two separate questions, pursued separately.

1. If two drivers are mutually offset in acoustic phase in a way that screws up the frequency response (in the far field), will the anomaly in the FR be audible?

2. If two drivers are mutually offset in acoustic phase in a way that doesn't screw up the FR (in the far field), can there nevertheless be an audible consequence?

The problem with making this question about time alignment rather than phase is that the question is too fuzzy. If a small driver and a large driver are mounted on a flat vertical baffle and acoustically phase-coherent crossovers are used, would they be considered time misaligned in spite of the acoustic phase coherence? There are several questions of this sort that reveal that the notion of "time alignment" is too fuzzy. This is something that often happens with certain questions in audio. The debate rages on because the question itself isn't as clear as it should be.

The first of the two separate questions is fairly mundane. If you end up with a peak or dip in the FR in the far field, does this matter? If there is consensus that it does, then it will be appropriate for other questions to follow, to identify the circumstances by which this will or will not occur.

The second of the two separate questions is the can of worms where we end up arguing about the usefulness of various kinds of test signals that will reveal variation in phase at different frequencies, and about group delay and so on.

In short, the question as asked is not a good question. Good questions lead to greater clarity in the understanding things, not to mass confusion.

 

[Frgirard]

The transducers alignment is a precise definition. Delay between the two transducers =0
Show by the step response
1.The suppression of the phase shift is a part.
2.The geometric an other part.

The 2 must be do with all brands. Is it the case?
The 1 no one has demonstrated the audibility.

 

[puppet]

Here's a thought experiment re: pathlengths of drivers as that pertains to time alignment.

When drivers are "time aligned" that refers to their individual audio signals/phase at the crossover region. We don't hear an individual response but a combined response when properly aligned. The "balloon", that is the wave front, is the result of the drivers combined response(s). Depending on the design of the xo network, the balloon is such that it covers a wide area and we don't/shouldn't hear an individual response. When we tilt such a loudspeaker, all we are doing is aiming the balloon in a different direction. The pathlengths don't matter as the individual driver responses still work to form the combined wave front, or the balloon, that we hear. The balloon shape and direction have to do with the xo network design, c-c distances, phase alignment and driver dispersion. Screw any of those up and the design becomes audibly flawed.

 

[Snarfie]

Clearly a difficult issue to reach consensus. In choosing equipment I have followed a simple idea. Choose kit that has low distortions, flat frequency response across a wide bandwidth and is time aligned as far as possible. This seemed to me to be the best way to reproduce both harmonic and percussive sounds.

I may well not be able to hear differences from this ideal but why take an unnecessary risk if I can afford the kit?

Regards Andrew

Besides low distortion an a flat frequence respons drivers must be inline (a physical soltution). Some say you can solve this problem with DSP thats a question to reach consensus on.

 

[Andrew s]

A certain resonance?

My KEF 201/2 with Uni-Q.
Regards Andrew

 

[ferrellms]

I posted this in a speaker review thread, and it got buried, so perhaps it was best to give it a thread of its own.

As I had mentioned, when I was getting into audio, companies and designers like Snell, Fried, and Thiel, amongst other notables, were the preeminent builders. As such, I recall them having a focus on time alignment of drivers. With many of today's powered models using DSP, I would imagine that this is a non-factor. However, does it make sense to ask Amir to measure things like step response, phase response (same? https://bksv.com/media/doc/17-198.pdf), and acoustic distance/source in the basic battery of speaker testing just to provide an additional perspective?

Also, I'm seeing lots of CSD's being posted that appear to have ringing or long settling times in the lower frequencies but no one is discussing them (or I missed it). Is the CSD plot being provided considered inaccurate, or are problems like this no longer considered a problem, audibly? https://www.audiosciencereview.com/...er-csd-waterfall-audio-measurement-png.67181/

Help a newb out!

I use Sonarworks with Genelecs and an SVS sub in a modestly treated room. Sonarworks correction will provide time coherence at the cost of a small time delay. This delay is noticeable when tracking or watching movies. Overall, the sound is excellent. But, as far as just sound goes, I cannot hear any difference between low latency (with no time correction), "optimal" with less time correction (11 ms delay), and full time correction (45 ms delay). This is with nearly instantaneous switching. So I just leave it in "optimal" which does not have enough delay to affect tracking or video watching. YMMV.

 

[dasdoing]

I use Sonarworks with Genelecs and an SVS sub in a modestly treated room. Sonarworks correction will provide time coherence at the cost of a small time delay. This delay is noticeable when tracking or watching movies. Overall, the sound is excellent. But, as far as just sound goes, I cannot hear any difference between low latency (with no time correction), "optimal" with less time correction (11 ms delay), and full time correction (45 ms delay). This is with nearly instantaneous switching. So I just leave it in "optimal" which does not have enough delay to affect tracking or video watching. YMMV.

find a nice kickdrum track at https://freesound.org/
not eletronic kick, find a really natural one with midrange content (batter sound).
after some switching you should hear a diference

 

[norman bates]

Some say jingling keys, rain, striking a wood block, or clapping are sources that are easier to "hear" a difference.
But yes dasdoing, a drum often has highs and lows that can be used to test "alignment".

Back on diyaudio, one said listening outside made it easier to get the acoustic centers matched up (sliding back and forth tweeter on a 6db time/phase alignment).
Assumably, inside, the multiple reflections reduced the audibility of "best" alignment of acoustic centers.

 

[ferrellms]

https://audioxpress.com/article/zero-phase-in-studio-monitors

Thanks a bunch - this pretty much settles it - zero-phase is not important for reproduction of music in a hifi system.

The article sums up the expert commentary (he commenters are all top, well-known, audio engineers (Toole, Klippel, etc) :

"As you can surmise from these remarks, everyone is pretty much on the same page. Phase is just not that hearable whether unaltered or rendered to a zero degree position. Zero phase may make very subtle improvements if you are listening in an anechoic environment, but whatever minor improvements you may have heard are lost in a listening environment where phase is scattered by room reflections."

 

[Keith_W]

Interesting discussion, thank you gents. I use Acourate, and because I have an 8 channel DSP system I am able to measure and time align the speakers. The procedure involved with Acourate is complex and time consuming, and after going through the whole shebang (took me hours), I determined that the time difference between tweeter and midrange was 5 samples at 48kHz, or 0.1ms. There was a greater difference between tweeter and woofer, at 40 samples (slightly less than 1ms). Theoretically, sound can travel 4m in 1ms, so the effect should be the same as placing the woofers 4m further away with respect to the tweeters (apart from volume). However, with actual listening I was unable to tell the difference between time corrected or not. But ... because I have gone through the whole exercise, and I know the values, I apply time correction anyway since it doesn't cost me anything, even though I believe the effect to be inaudible.

 

[ernestcarl]

Thanks a bunch - this pretty much settles it - zero-phase is not important for reproduction of music in a hifi system.

While I agree to the general sentiment of our expert consensus already, even "in-room" and not so perfectly "anechoic" environment, when time domain correction is performed "correctly" in the bass region and ABX'd properly... sensibly flattening phase can actually be really, really very easy to hear, say, with a infinitely looped kickdrum test signal/track. In fact, it may be so obvious that a simple A/B listening test with a convolution filter is enough. Testing and room acoustic conditions matter very much, of course...

 

[fpitas]

Phase, Time and Distortion in Loudspeakers

sound-au.com

Since I have the DSP, I time-align my drivers using digital delay. I can see that analog methods of time alignment can be tricky.