On Nov 1, 2:49 am, " wrote:
I picked one of your website topics at random just to see what talent
resides within... I chose

Ooh, that should bring some excitement to your day. But, tell me, Mr
Mayberry, wouldn't your wife and children prefer you rather to keep
your mind on earning a living?

"Point source speakers"

I wrote about point source speakers? Well, you can knock me over with
a feather.

You selected the Lowther Fidelio as your example. This is a folded
transmission line speaker enclosure using the EX2 drive unit with
integral phase plug.

Erm. It's a dual-channel horn; the horn is behind the driver, rather
than in front of it as in the sort of PA speakers you are no doubt
used to. Once you know that, perhaps you will wish to work out the
expansion without me telling you, just to show how much smarter than
me you are. There's a good picture of a Fidelio-type horn under
construction in my studio somewhere on my netsite.

In no way is this a good example of a point source loudspeaker.

Perhaps not from your perspective. I imagine Fidelio enclosures and
Lowther drivers would be a bit expensive for your system.

The phase plug "equalizer" alone would disqualify it, let alone
loading the woofer with the complex acoustic impedance of a
transmission line.

Do you really think so? Even better, do you really think that, given
the fact that you have already failed to bully me into submission, I
care **** what you think?

Think about what that plug is doing- changing the
path length of the signal transmission in order to lower the
directivity index and decrease on axis beaming. They are commonly
used in professional audio (see Engebretson's Altec Tangerine phase
plug paper from the early '70s for reference) compression horn
tweeters.

That's what techies are useful for, Mayberry. Why don't you make us a
precis of the paper and we'll decide if it is relevant or perhaps
interesting even if irrelevant.

The device has a number of different copyrighted names, but
the effect is the same- signal smearing.

The Nyquist plot of this speaker is going to be all over the place, as
will the polar plot as a result.

Actually, I own a couple of pairs of Fidelio with PM6A. I don't need
some clown who's never heard or seen one telling me what "this speaker
is going to be", I already know.

You really need to do your homework and crack open the textbooks to at
least understand what makes up a point source loudspeaker prior to
pontificating on it.

Crap. A point source speaker creates a sound emanating or seeming to
emanate from a single point. The "seeming: to take account of my Quad
ESL63 with their faux point source.

Don Davis's Sound System Engineering might be a
good start.

What a pedantic waste of time you are, Mayberry. Didn't it occur to
your cramped mind that I own these speakers and have measured them
but, even better, listened to them? Who cares about a "good start"
when you can instead make a permanently satisfying finish?

Are we done yet?

Andre Jute
"I was at a board meeting for the LA Chapter of the Audio Engineering
Society last night on XM Satellite radio audio and data transmission.
Sadly, we missed you there, and at the SMPTE and Acoustical Society
recent meetings as well. Everyone was asking, 'Where is that wonderful
Andre Jute? The world just doesn't rotate without him...'" -- John
Mayberry, Emmaco