Time-Phase-Alignment- Point Source-Classical Musicians


Here's my story. I owned a HiFi store in Providence, RI in the 80s. We had a huge customer base of professional classical musicians. They would come into the store and audition speakers....KEFs, EPI, Advent, AR, etc. We had a very well designed switching system that could balance the SPL of the speakers using a sound pressure meter for A-B comparison. As we would play various, extremely popular  speakers they would sit there patiently. Just about 100% of these musicians would light up when we would play B&O Red Line speakers, Dahlguist DQ10s and Magnepans......the only thing these speakers had in common was some form of "time alignment". The drivers were "aligned" in some fashion or in the case of the Magnepans, a single panel in space. They reaction always amazed me. And this happened time and time again (no pun intended) I remember reading an article many years ago about 15% of the population being very susceptible to what was referred to as "time distortion" in loudspeakers. I suggest that folks that really know what live music or maybe their particular instrument  is supposed to sound like are among that 15%.......I'm extremely impressed with my recent acquired KEF LS50 Metas and my Magnepan MMGs among all the hundreds of speakers I've had the pleasure of auditioned in a 50 year career in HiFi. 

 Recently , after listening to the Metas for a few months, I was smitten by the concept of Point Source loudspeakers. This led me to a number of Single Driver, no crossover designs that are receiving rave reviews. The brand that really got my attention is Pearl Acoustics and the Sibelius speaker. Since I couldn't afford tio buy a pair, I decided to build what some consider the DIY version...The Pensil 10.2.....Totally blew me away! So simple to build....So easy to listen to! (You can read all about my build here...

 So where is this going.....Is there any validity in anything I've written? Has anyone else experienced similar?  

rbertalotto

I feel that I get very good results using my DEQX HD4 DSP to time and phase align my triamplified fully horn loaded DIY speakerts. 

I've had Pearl speakers for the past few months and can support all of your remarks about point source speakers.  I find the "realism" and detailed soundstage quite amazing compared to any of the many speakers (most far more expensive) that I have had over the years... 

While the effect is similar, their sound stage imaging is far better that any electrostatic or membrane speaker I have listened to. As for those who think a small speaker won't be able to reproduce base well (as I was when I took the plunge to order a pair), everyone who I invite to listen is amazed (as I am) not only in the quantity, but in the quality of the base they produce. The tuned port they have designed produces excellent base.

Bravo to you for exploring the DYI possibilities inspired by the Pearl speakers!  Please keep us informed of your progress.

Not sure if this is applicable or not, I seem to remember Decware making some single point speakers for fair money.  

I wonder if you can measure time alignment outside of an anechoic chamber?

Yes, very easily, for the most part even using basic measurement tools like REW or OmniMic. Using an impulse response you would see the tweet and mid impulse fairly easily and even the woofer somewhat until the room reflections show up in the measurements.

You can at least see if a speaker is time aligned or not, but gettting precise measurements would be difficult due to room reflections.  Take a look at figure 7 in this review:

 

I wonder if you can measure time alignment outside of an anechoic chamber? Certainly don’t see ASR or others reporting any measurements if this is supposed to be important. I also observe many box speakers claiming time alignment in their design including Gershman, Wilson’s etc.

Always here for DIY!

A kind of interesting take too is the Woofer-Assisted Wide Band.

It is essentially a 1 driver speaker down to about 200 Hz or so, when a conventional crossover brings a woofer into the mix. Another way to think about it is a 2-way with a very low crossover point.  Many feel it has all the benefits of a 1 driver speaker, but with great bass.

My speakers are very good at 3D imaging/soundstage, but I had Thiel 1.6es in my system for a bit and there was something special about what they did in that realm that I attribute to being time/phase coherent.  Just my take. 

Thiel 1.6es were (are) great speakers.....A real bargain when you find them used in perfect condition...

 

My speakers are very good at 3D imaging/soundstage, but I had Thiel 1.6es in my system for a bit and there was something special about what they did in that realm that I attribute to being time/phase coherent.  Just my take. 

Roy,

The $6k Pearls attracted my attention as well. I am anxious to 

listen to a full range driver speaker. Nice work!

Vandersteen has been chasing time and phase and much more since 1977…. not everyone’s cup of tea but many professional use them in a variety of ways…. Enjoy your journey and congratulations on your successful DIY build…lovely cabinets - enjoy the music in great health ,

jim