Time aligned speakers - do they make sense?

[Dogen]

I see some speaker brands claiming to be physically time-aligned, usually by titling the speaker back so the tweeter is farther from the listener. Is this truly effective? It seems if there’s a positive effect, it would be for only one narrow listening position (which may not be where you’re sitting ). Are there any demonstrated, measured benefits to this design, if your head isn’t in a clamp? Or are there other benefits to this design?

 

[ppataki]

If drivers are time aligned in a multi-way system that will clearly be visible in the step response curve. (= there will be one peak at 0ms instead of multiple skewed peaks representing the time misalignment between the drivers)

If this is audible or not......

I used to have a number of multi-way speakers and when optimized they sounded better (more cohesive sound stage, and speakers 'disappearing')
But this is subjective of course

Search for step response in this forum to get to know more

 

[Frgirard]

I see some speaker brands claiming to be physically time-aligned, usually by titling the speaker back so the tweeter is farther from the listener. Is this truly effective? It seems if there’s a positive effect, it would be for only one narrow listening position (which may not be where you’re sitting ). Are there any demonstrated, measured benefits to this design, if your head isn’t in a clamp? Or are there other benefits to this design?

If you call time aligned: all drivers plays at the same time with one peak in the step response, rare are the brands.
Psi audio do that. Athom only between the mid and the tweeter or the tweeter and the woofer...

With rephase you can do for any speaker. I did on my K+H o300 and my kh420. I have not heard a difference.

All brands are sensible to physically align the drivers.

 

[Mnyb]

I migth work better with true coaxials drivers , for a multiway with large separation between the drivers ( in respect to wavelength ) the correct phase sumation will possible only happen at one axis at one distance on one point , with wide directivity and a lott of room reflektion ? who knows

 

[DVDdoug]

It could be important but it's more about phase than time. If the waves from the tweeter and midrange (or woofer) are out-of-phase at the crossover frequency they will cancel and you'll get a dip in the response.

...Just checking with an online calculator, 5kHz has a wavelength of 2.7 inches. So if the midrange is 2.7 inches behind the tweeter, the tweeter will lag by exactly one wavelength and they are back in-phase. If there is a 1.35 inch difference that's a half-wavelength and they will be out-of-phase.

Exactly one-half wavelength is 180 degrees so that could easily be corrected by reversing the connections to one of the drivers. Also, crossovers often introduce a phase-lag in the low-pass and a phase-lead in the high-pass so that should be taken into account.

...You'd also have to calculate the effective radiation plane from the drivers, which are usually a cone or dome so it's not so obvious. (The manufacture should know this.)

At lower frequencies (longer wavelengths) it's not as critical since there will be smaller phase differences.

 

[MakeMineVinyl]

Time alignment helps with stereo imaging precision. If your room doesn't allow for optimal speaker placement to start with, you're not going to hear any differences time alignment can make. You also need to know what to listen for; if you've never heard optimal imaging or only listen to recordings without very good soundfield representation, you'll likely not hear the subtle differences.

Time alignment is a very old concept which goes back to the 1930s and the Shearer Horn.

 

[ernestcarl]

In most real domestic room listening environments, perfect linear phase response and time-alignment is kind of 'meh' anyway:

My main-floor family living room using conventional 2-way speakers -- left and right response measurements spread across all listening areas:

 

[gnarly]

If drivers are time aligned in a multi-way system that will clearly be visible in the step response curve. (= there will be one peak at 0ms instead of multiple skewed peaks representing the time misalignment between the drivers)

If this is audible or not......

I used to have a number of multi-way speakers and when optimized they sounded better (more cohesive sound stage, and speakers 'disappearing')
But this is subjective of course

Search for step response in this forum to get to know more

I share your subjective take from my experience with multi-ways and rather precise time alignment.
As luck would have it, moments ago i did a quick indoor tune on my current project.....
here's the step and impulse, and a pict of the speaker....a 4-way MEH main for use with a sub

I absolutely love the sound i get from fine tuning time alignments, to that precision.
Everyone should hear it outdoors to fully appreciate it, i think..

Oh, by time alignment I mean a flat continuous phase trace across all driver sections, with time-of-flight removed from the measurement.
Constant delays, be they digital, analog, or simple geometric stacking of acoustic centers, are just a part of "time alignment"

 

[itz_all_about_the_music]

I see some speaker brands claiming to be physically time-aligned, usually by titling the speaker back so the tweeter is farther from the listener. Is this truly effective? It seems if there’s a positive effect, it would be for only one narrow listening position (which may not be where you’re sitting ). Are there any demonstrated, measured benefits to this design, if your head isn’t in a clamp? Or are there other benefits to this design?

Comments from Jim Thiel (deceased), in the application on 1st order x-overs, may shed some light. See: http://www.soundstagenetwork.com/yfiles/yfiles200107.htm

 

[Sancus]

There are some active designs that provide linear phase down to some frequency, the sacrifice being increased system latency(which doesn't really matter for music listening). To me that's the only worthwhile way of doing this.

Genelec Ones and Kii3 support this, and tbh I don't notice much if any difference with the Ones in that mode. It's hard to A/B test quickly though. I just leave it on because why not, the +4ms of latency isn't important.

 

[HarmonicTHD]

Toole in his book (chapter 4 or so) says something along the line of „… no evidence, that differences of phase are audible …once the signal leaves the speakers …“. Or so. (I am not quoting exactly).

Is that a different context and therefore does not apply here?

 

[gnarly]

There are some active designs that provide linear phase down to some frequency, the sacrifice being increased system latency(which doesn't really matter for music listening). To me that's the only worthwhile way of doing this.

Yes, for sure. The modern way to fly imo

The step and impulse for the active DIY MEH i posted in #9, is a linear phase design.
Xovers at 100, 300, 750, and 6300Hz. All are 96dB/oct LR's.
Uses 170ms of FIR latency, and allows flat phase all the way to <30Hz.

Here's the mag and phase that went with the step/impulse. Again, just the main from 100Hz up....can't tie the sub in till outdoors.

 

[gnarly]

Toole in his book (chapter 4 or so) says something along the line of „… no evidence, that differences of phase are audible …once the signal leaves the speakers …“. Or so. (I am not quoting exactly).

Is that a different context and therefore does not apply here?

With all due respect to Toole...I'm totally unconvinced of his conclusions regarding phase audibility.
Certainly the uniform standard-type speakers that show up in the book, didn't have the capability to demonstrate flat phase across the board, my guess doubly so when a sub was added.

 

[mhardy6647]

The thing is, wavelength varies continuously with frequency, so even physical time alignment (a la the mid-1970s Polk Audio "PolkStands") is an approximation at best (except for a couple/three specific frequencies) -- I would think(?!?).

Like the Playtex Living Bra of an even earlier era the Polkstands were designed to lift and separate -- and, using brute force, to time align.

 

[Bleib]

Yes, it makes sense. Timing errors can lead to a bit of a muddy sound. This is why both left and right speakers should be measured to be as close as possible too.

 

[Dogen]

The thing is, wavelength varies continuously with frequency, so even physical time alignment (a la the mid-1970s Polk Audio "PolkStands") is an approximation at best (except for a couple/three specific frequencies) -- I would think(?!?).



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Like the Playtex Living Bra of an even earlier era the Polkstands were designed to lift and separate -- and, using brute force, to time align.

And an approximation in a very small area of space. So the tweeter moves back 3 inches, and the space where things are aligned moves a little. But what if your ears are not in that space?

 

[MakeMineVinyl]

And an approximation in a very small area of space. So the tweeter moves back 3 inches, and the space where things are aligned moves a little. But what if your ears are not in that space?

With Linkwitz-Riley crossovers at least, the physical vertical alignment (or digital alignment) of the drivers across the crossover point determines the vertical lobing between the drivers.

 

[Another Bob]

With non-coincident drivers, any speaker can only be phase- or time-aligned at one particular axis, regardless of whether the alignment is done electronically or physically. This is why the vertical off-axis frequency response looks so bad. I consider a speaker to be phase-aligned on the axis where the frequency response through the crossover region is smoothest. As mentioned above, it is time-aligned when the step response is optimized. I have time-aligned speakers using electronic crossovers, and I think there is subtle, but noticeable improvement, which I notice mostly as improved imaging.

 

[gnarly]

The thing is, wavelength varies continuously with frequency, so even physical time alignment (a la the mid-1970s Polk Audio "PolkStands") is an approximation at best (except for a couple/three specific frequencies) -- I would think(?!?).

yep, back in the day when phase could not be altered independently from frequency response ...and not to mention that all xovers were IIR with their various levels of phase rotation.....well, time alignment was at best a rough approximation

So a few frequencies matched up ...and manufacturers/folks made a big deal about even that...

Ironically, nowadays when phase can be precisely aligned for all frequencies, all wavelengths....
most folks refer to the past and say "we never heard phase matter before" (when it was impossible to get right, LOL)...
and think yesterday's impossibility applies to today....

Gotta love holding on to what "we know", huh?

 

[thewas]

Linear Phase in Studio Monitors - the responses of Dr. Floyd Toole, Dr. Wolfgang Klippel, Andrew Jones, and James Croft

Imho quite a good read. https://audioxpress.com/article/zero-phase-in-studio-monitors

www.audiosciencereview.com