A history of Time Aligned Loudspeakers

[gberchin]

Here's a little theoretical study that I put together about driver offset effects upon frequency response. Please be aware of the disclaimers in the third paragraph.
Also please notify me if you find any errors.

 

[Thomas_A]

Ino Audio pi60 around 1985

 

[Salt]

Here's a little theoretical study that I put together about driver offset effects upon frequency response. Please be aware of the disclaimers in the third paragraph.
Also please notify me if you find any errors.

Excellent.

 

[robh36062]

If the Step Response doesn't look like this you need not apply. This is the audibility of Group Delay. Is time alignment worth it?

Rob

 

[Daverich4]

No Wilson speakers are time aligned

Isn’t that what they’re trying to do? On some of their speakers the different distances and angles of the tweeter and midrange can be adjusted. That isn’t effective?

 

[Henrik]

I miss my 1980 F3 Lyd Trapez by Ole Klifoth

 

[Sal1950]

The 'magic' of the Time Windows was in the crossover.

Thanks for the brain food.

It would not fit modern aesthetics and the practical reality (and economy) of most modestly sized homes, however.

Folks that can afford Wilson Autobiography's don't own "modestly sized homes".
Price: US$788,000 per pair LOL
Depending on your POV, they are very Kool looking.

 

[MFA]

Isn’t that what they’re trying to do? On some of their speakers the different distances and angles of the tweeter and midrange can be adjusted. That isn’t effective?

Drivers acoustic centers only. Not min phase as shows time vs frequency.

 

[MattHooper]

My favourite time/phase coherent
loudspeakers I’ve ever heard. Thiel 3.7s that I owned:

Though I sold those because they were a bit too big and I’m currently rocking the slightly smaller version, Thiel 2.7:

I’ve mentioned before: I have no idea whether the time phase coherence of the design figures into what I hear with these speakers, but the Thiels produce the most solid image focus, the most dense imaging, that I’ve ever heard from loudspeakers. It feels they lineup all the sonic information of any instrument or voice in such a precise tidy way, there’s a higher impression of palpability and sonic density which I find addictive.

My other pair of floorstanding loudspeakers from Joseph audio go a different way with a high order crossover with very steep filters.
I like the sound of both speaker brands, but even though the Joseph speakers have a great reputation for sound staging and precise imaging, they still don’t sound as precise as the Thiels.

 

[norman bates]

I used to be in the time aligned camp.

 

[Sal1950]

I used to be in the time aligned camp.

Until ???

 

[Torin Krell]

Another speaker designer that considered time alignment, phase, as well as diffraction before these considerations were common was John Bau who started working on his line of Spica speakers in 1978. This detailed IAR review of the Spica TC-50, likely John Bau's most popular speaker model, highlights its acoustical design features along with some measurements:

 

[mhardy6647]

Matt Polk (and company), ca. 1975, took a brute force/bargain basement approach towards time alignment.




The Polkstands - as they were known - had four tenacious (albeit not sticky per se) rubber pads attached to them that generally prevented unscheduled assembly of loudspeaker and stand.


Mind you -- this one is pushing 50 years old, and was purchased as a demonstrator anyway; i.e., it was a bit scruffy when I bought it in 1978.

 

[mhardy6647]

I think (?!?) that a case could be made for one of the suite of substantial improvements offered by Doug Sachs' EDIT Sax's [thanks to @Sal1950 for catching my error!). Mastering Labs crossovers for the venerable (and once ubiquitous) Altec 604 Duplex (coaxial) studio monitors - compared to the stock Altec XOs - was an improvement in 'time' alignment for the treble and LF sections of the Duplex.

The ML XOs were (are) a mammoth improvement over Altec's stock XO for the Duplexes of their era.

 

[Esprit]

Infinity Modus

 

[Sal1950]

This detailed IAR review of the Spica TC-50, likely John Bau's most popular speaker model, highlights its acoustical design features along with some measurements:

Wow, that's the first time I've heard J. Peter Moncrieff's IAR mentioned in like forever.
A early semi-objective review mag that along with Audio Critic let the way for sites like ASR.
Kool

 

[Sal1950]

I think (?!?) that a case could be made for one of the suite of substantial improvements offered by Doug Sachs' MasteringLabs crossovers

I think you mean Doug Sax, RIP Doug.

 

[Apesbrain]

First "time-aligned" speaker I recall is the B&W DM6:

 

[Hayabusa]

These speakers are excellent examples of misplaced priorities in audio. If you stagger your speakers on a baffle like that, you will ruin vertical directivity and possibly horizontal directivity as well, if not done properly. Bear in mind, sound travels 343mm in 1ms. So if the baffle is stepped by 34mm, it will provide 0.1ms of time alignment. Which do you think is more audible? A 0.1ms time alignment, or poor vertical directivity?

0.1msec timing error between mid and tweeter would give you cancellation at 5Khz and could be audible..

 

[xanalog]

Is "time-aligned" and "time-coherent" mean the same thing, in speaker design; or do they have different nuances?

In the case of KEF Uni-Q and MoFi SourcePoint offerings; they are coaxials/concentrics (AndrewJones calls his creation "co-incident").
Both align their acoustic centers but are not exactly time-aligned. Are they?

I used to be in the time aligned camp.

Me too!
RichardVandersteen was born as a cheap but clever designer. He gave us time-alignment but cut costs by having no cabinetry/woodwork.

I was a sucker for a few generations of his model 2C iterations and was perfectly happy.
I am no longer time-aligned since I have become a MoFi SP10MP fanboy of late.