Since the real source is nothing like the theory, theoretical crossover shapes for the LP will never work right. You must end up with the correct curve after it goes through both the X-over and the driver. People who use fixed "named" electrical crossovers will not find that they work out like you want when joined to real-world drivers.
Hi Gedlee, I accepted it to be true because the polars I’ve seen reflect. I didn’t know that was possible for a horn to have directivity at a wavelength larger than the diameter of its opening, can you provide polar charts/graphs to illustrate to the thread, please and thank you.
I am so sorry, I misread your Email. You are correct. If the wavelength is larger than the mouth then the directivity is pretty much determined by the mouth diameter and the waveshaping aspects of a waveguide are lost,so lots of things can happen.
Since the real source is nothing like the theory, theoretical crossover shapes for the LP will never work right. You must end up with the correct curve after it goes through both the X-over and the driver. People who use fixed "named" electrical crossovers will not find that they work out like you want when joined to real-world drivers.
Gotcha, and very true.
I have happily found out (thx to Pos) how to get the electrical response of a crossover to equal the measured acoustic response of both crossover and driver.
It does require a fair amount of active IIR EQ's, but it doesn't depend on FIR or linear phase.
And I think it kinda makes it where there is no good reason to use anything other than fully complementary LR crossovers...just choose your order, and whether you want minimum or linear phase.
And I think it kinda makes it where there is no good reason to use anything other than fully complementary LR crossovers...just choose your order, and whether you want minimum or linear phase.
I never use LR crossovers and my crossovers are never even symmetric. I use what works best and have never found that "named" crossovers work. Actively it's pretty easy to do, but passively is another story.
The GSU-D04 is undoubtedly a very capable driver, but presumably also very expensive.
20 years ago, its performance was pretty unique. Nowadays, I would definitely consider the Axi2050 first.
A Faital HF201 is also an excellent 2" driver for a whole lot less.
Well, that Celestion CD certainly looks amazing, why is it not very popular? And why aren't we talking about it more? Only because of the price when old stuff sells for much more?
I have 15" woofers (JBL 2226) and 1.5" compression drivers (JBL 2453, spare 2447), so broadly similar use case to this thread, you, Wayne Parham and, just a little less, Earl.
My room suits a 90 to 70 horizontal beam-width, I aim nominally at 80.
Where I differ from Earl is that I aim for a little narrower vertical, around 45 to 50, partly because the house structure is concrete and brick and reverb is hard to control.
The optimisation of the directivity of non-axisymmetric horn + woofer is a problem that I haven't seen much written about.
Bill Waslo pointed me at Wayne's posts and they made me think.
When I did some calculation for the 80:45 ratio I came up with an answer a little different.
Somewhat to my surprise what looks to have promise is close to a square horn mouth.
This needs a little nip-and-tuck from mathematically idealised horn but should be minor.
Then the woofer is placed sufficiently close to the horn to hold the directivity but stop the waist band around crossover.
For a double woofer the extra distance is problematic if stacked vertically.
Vertical polars would improve if they were placed horizontally, obviously horizontal polars would need attention, not sure how this would play out in the 4722.
My idea really needs to be confirmed with a FEM/BEM simulation and I have started on ABEC3.
But it's a lot of work and I have physical speakers to finish first.
Best wishes
David
Dave: what would happen if rater than horizontal woofers or stacked woofers you placed oe right next to the horn and the second woofer around the corner on a side panel?
Only because of the price when old stuff sells for much more?
2+2=10😉
Tonight, I'll have to settle for this (x2 = 4 point):
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2 pairs of Sony SUP based MTMs and yes, those are 15" woofers.
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GM wants me to build this and put in my basement, average Michigan basement, maybe 8ft high lol?
This batch of Sony stuff from the Sony Studios in Culver City was sold on ebay about 15 years ago for 600.00 bucks, including all the cabs.
Not bad, if you consider 1 GTS clone of the Sony SUP-T11 costs > $4000.
Not bad, if you consider 1 GTS clone of the Sony SUP-T11 costs > $4000.
This is what the SUP-H11 horns look like from the front:
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GM wants me to build this and put in my basement, average Michigan basement, maybe 8ft high lol?
You live in Michigan? You should come by and hear my system.
We don't differ in principle.
I hope not. I think what I wrote reflects this.
Of course, there are differences in our requirements and cost/benefit trade-offs.
My home acoustics are different from the typical American (plasterboard construction), just for a start.
...I actually made a 90 x 60...far more complicated to fabricate.
Can you post any pics?
I am curious to see how you fabricated and what you came up with for the throat transition, mouth shape and so on.
I assume this was a while back, these days CNC fabrication is commonplace - a CNC router to cut a foam pattern seems routine.
Next, the lack of vertical control made the crossover situation worse in the vertical direction
This is the key, I think I can improve the vertical polars both above and thru the crossover frequency but I need to confirm this.
In my room I simply put a deflector... which solved the problem.
When you say "deflector" do you mean absorber or reflector?
Some treatment is on my to-do list too.
But it would still be nice to have the better vertical polars, makes a more tolerant speaker and a little more efficient.
Ideally I don't want to sent sound upwards and then have to put an absorber up there to soak it up.
Finally, it is the horizontal control that is imperative and the vertical is of secondary concern...
Yes, I commented on this in a prior post.
Best wishes
David
...[W]hat would happen if rater than horizontal woofers or stacked woofers you placed..the second woofer around the corner on a side panel?
Hi Moray
In my speakers it wouldn't fit... there isn't much in the way of side panels, the box has slanted front face to aim the woofer and blend with the horn.
But I have tried to work out some alternative set ups.
This idea could probably be made to work well with correct crossover to match the phases and amplitudes for both on axis and nice polars....what if I ran dual td15ms side by side and dual 15h side by side below the 15ms
Main problem is simply that it will be very expensive.
JBL used 4 woofers close packed in a diamond pattern (tall vertically) for some expensive cinema installations.
Best wishes
David
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So as I follow the thread almost since day one Ill ask a recap question that might help concentrate the HF options.
From the available for sale CDs if you want to crossover a 15in at a max of 800 (I would prefer less) and pay 500eur or less per side (so no cellestion 1000usd) what are the hifi (low power) top options?
Ive seen so many recommendations for different configurations that I dont know if there is a general verdict. Most CDs go up nicely to 17-18k but Im not sure which actually does a quality job up to 20k (not that my ears go over 15 but thats another thing).
Im planning to order a 4594he if I can’t get a single driver alternative.
Ill probably make a tratrix wood horn (300hz-400 size or thereabouts) for it or an 18sound as a of the shelf thing.
From the available for sale CDs if you want to crossover a 15in at a max of 800 (I would prefer less) and pay 500eur or less per side (so no cellestion 1000usd) what are the hifi (low power) top options?
Ive seen so many recommendations for different configurations that I dont know if there is a general verdict. Most CDs go up nicely to 17-18k but Im not sure which actually does a quality job up to 20k (not that my ears go over 15 but thats another thing).
Im planning to order a 4594he if I can’t get a single driver alternative.
Ill probably make a tratrix wood horn (300hz-400 size or thereabouts) for it or an 18sound as a of the shelf thing.
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