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Re: From Wayne Parham - Re: Patentable claim

You wrote:

> > If not acting as an acoustic transformer, what then explains the
> > impedance curves which clearly show "radiation resistance" and how
> > then do the mid drivers reach an electroacoustic efficiency
> > greater than the compression driver?

Filters modify impedance and act as reactance without matching impedance.

True, but the "efficiency" I was referring to was based on the radiated acoustic power compared to the electrical input
power, the fact that part of the system is electrical, part electroacoustic and part acoustic seems secondary as it is the
system I was testing.

I expect your horn will load the midrance
band for a couple of octaves and that's all. That - and the fact that you use several of them - is why midrange output is
higher.
But the horn unloads a couple octaves above its flare frequency, and afetr that, it is acting only as a reflector.

I think your starting to get it, YES each driver or set of drivers can only load the horn for a couple of octaves.
But also that the frequency range of the horn is dictated by the size of the horn and that one can stack up horns of
differing sizes and frequency range to get a single horn that covers a very wide frequency band using multiple sets of
drivers.
"All" one has to do after that is arrange the drivers, acoustic paths and electrical filters such that when in impulse or
wide band signal is produced by the compression driver, that it is "joined" at the right phase and time with the mid
components and then so on down.
Since it possible to actually measure the drivers and filters separately or in combination, it is not impossible to get
pretty darn close to dead on. At that point the results are as good as the drivers permit.

> > To date I have not made a horn which loads "the entire audio
> > bandwidth" ( the 10 octave span from 20 Hz to 20 kHz ), the
> > largest span is from about 200 Hz to 20 kHz but I am casually
> > working on one which I hope will cover 100 Hz to 20 kHz. Since
> > the math says it should work, I don't see why it wouldn't but the
> > issue is my efforts are governed by what makes the most logical
> > product.

Your use of the phase "cover 100Hz to 20Khz" is ambiguous. If you're talking about making a horn that provides
acoustic impedance matching over a span of seven octaves, you're wasting your time.
You can load the diaphragm(s) for two or three octaves, and not more.

I am talking about an efficient horn loaded system which uses one physical horn shape to cover that entire frequency
range. Polar plots SHOW that the radiation pattern of a Unity horn is that of of a single source, no lobes, no
interference.

> > You insist it won't work yet Energy vs time measurements show it
> > does, you insist it can't be a point source yet polar measurements
> > show it is.

Did you ever consider that your measurements might be in error? Not to be rude, but I've even considered that they
were "hand picked" and that you've only shown those that support your case.
You have distanced yourself from the Lambda graphs, but I find them to be extremely telling.

Surely you jest, dude, I have taken thousands of TEF measurements, I have had them at my disposal for nearly 20
years and I was even invited to present at a TEF workshop on "exotic measurements with the TEF" twice.
Ask anyone in Pro audio about our spec.'s and they will tell you our stuff meets its spec.'s.
For you to suggest that the countless measurements involved were all in error is, well, not likely.

I will tell you what I told Nick about the "indoor" measurements he took, that for one if it was a TEF measurement, it
would show that there were reflections leaking in and that since I don't use MLS I couldn't tell much more.
I urged him to get an old TEF machine.

> > You insist it is an "approximation" while it was designed, built
> > and fine tuned entirely based on actual measurements of time and
> > phase of the parts used.

If you've done good work, then it is a close approximation.
But to say it's accurate in both the time domain and the frequency domain simultaneously is not possible.
It is not a point source. It is an array, and the scale of frequencies within the array is too course.

An array of sources that are small acoustically (less than 1/4 wl in size) can combine totally and coherently IF they are
less than 1/4 wl (1/3wl if some directivity is acceptable) apart, center to center.
In the range they operate in, the mid driver exit holes and horn dimension are less than 1/4 WL and load the horn as a
pressure (being too small acoustically to make a beam).
As the pressure is presented in a dimension less than 1/4 wl, acoustically, that is a point source.


> > You assert that by using even a fastwoofer like the 2226 which
> > only has an internal delay equal to .64 feet (I just measured one)
> > and by using a crossover where signals above Xo come out
> > significantly AHEAD in time of those coming out of the low pass,
> > that by moving the hf source still further ahead in time,
> > that "this" fixes the time problem. Maybe fixes isn't what you
> > mean since you do say the ear is not sensitive to time.

No, Tom, I have not. I do not promote alignment of drivers, by either moving them forward or back. I submit that
neither will correct a speaker's time alignment.
There are two planar sources separated by a distance, so even if they are completely
100% synchronized with one another - crossover, drivers, everything - there is still parallax between them and the
listener. You cannot correct this problem in all positions and at all frequencies.
You can only pick a position and frequency, and make
an adequate compromise. The best solution is that which makes the best compromise for the task at hand.

You say "planar sources" but the drivers we are using are acoustically small, a "point source" and in fact do combine
seamlessly IF they are combined at less than 1/4 wl at the largest point.
I don't care if the compression driver is not "in time" at 100 HZ or where any driver is in time when its way out of
band, the only time the driver to driver relationship matters is in the range where the exchange from one to another is
being made and when they are in the operating band.

> > I am not sure if you really don't understand or are posturing in
> > defense of "your approach" that you refer to but if you really
> > don't get it, explain at what point the concept is inconsistent
> > with the physics and I will try to explain it further.

I understand completely. And "my approach" isn't germane to this discussion. My approach is actually no approach
because I assert that a filter cannot be accurate in both the time domain and the frequency domain, simultaneously.
Our loudspeakers are collections of filters - They are electronic filters and acoustic filters. So I have no approach but
rather a position - and that position is that the Unity device is also bounded by these same physical laws too.

Well I guess in Waynes world all knowledge is known leaving no room for a new approach.
You, in an earlier post, went on to recite how your work is based on a solid foundation and referred to a paper
written in part by Don Keele.
Next time you see Don, ask him about my designs, what I do, where I fit in the loudspeaker industry, I figure when he
hears the speaker, an explanation and then says "hey Tom that's a cool idea" that it means something too.
He "gets it" may he can explain it to you.

Tom, I'm sure that the Unity device is a good product. But you must understand - When you insist that you can make
a horn provides acoustic loading from 100Hz to 20Khz, you are saying something that is not unlike what would have
been said by snake-oil salemen of the 19th century. This is also true when you say you can make a filter - no, a
collection of filters - simultaneously accurate in the time domain and the frequency domain. I honestly expected more
from you.

Wayne Parham

Wayne I have to say I honestly expected more from you too.
I have been looking at a lot of old posts today , it seems that you have made dozens and dozens if not more posts
about the Unity horn in the last year or so, you had made this a personal crusade "to stomp this out".
In the end it is exactly the kind people I had wanted to Unitys to go to that you have harmed, how many that were
thinking about it didn't get it because of your tirades. Those tirades driven because you felt threatened or something
and based on your misunderstanding of how things work and lack of test equipment to find out for yourself..
Just as bad, you harmed Nick's business, he is a nice guy and one of relatively few places a DIY'r can get cool stuff,
these are the people that need support, not someone crusading against them, especially someone who is wrong to
boot..

You insist that the Unity doesn't work but will not or cannot answer any of my questions related to getting you to
explain on what grounds you base your insistence. You even suggest that the measurments are wrong, when the fact
is, you are wrong, I would guess most of the folks reading this know it too.
I suspect you are feeling like you took a good long Whiz into a campfire and now are finding having to stand in the
"steam" unpleasant.
After seeing what you have been saying to people, I realize I have been too patient, there seems to be no substance
to you technical argument and continued jumping up and down saying it can't work is boring.
Enjoy the steam, breath deep.

Tom



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