Horns - Necessary to complete the Audiophile Journey?

[tuga]

OH SORRY, Do I have to call the JBL's "wave guides" to be PC?
Yep I Guess.

At best your JBLs have a horn tweeter. Perhaps it's a horn, or maybe just a waveguide.

At Klipsch there is no "old way" , There's only Paul W. K. way.

Perhaps that's not a good thing. Klipsch's horn designs have crystallised in time.

 

[MakeMineVinyl]

Bondo, an unusual product to use for dampening? It does become very hard after fully cured but I imagine a nice thick application would have positive results if from nothing else than it's pure mass.
I wrapped my old Klipsch LaScala's with something that I can no longer remember.
Quite often today when I see those TV commercials for that FlexSeal product I think about how it might just be the perfect substance to dampen something like the outside of an ole school horn. Comes in a very thick liquid form and could ultimately be applied about as thick as you wanted. Dries to a very pliable rubber like substance.

Thank goodness that's something we don't have to give much thought to with modern horn speakers.
In any case I'm not about to start tearing apart my JBL HDI-3600's, it might void my 5 year warranty. LOL
View attachment 160407

Aquaplas is the most preferred damping material but unfortunately it's impossible to get as far as I know. The white color on older JBL speakers was Aquaplus being sprayed on the cones. I put about 3/8 of an inch to half an inch of Bondo and it does work very well and makes the horn absolutely inert. You're more likely to injure your knuckles rapping on the horn then to hear any resonance. There's adoptedly other good products to dampen horns such as tar and tar paper but Bondo sets up nice and fast, and of course it can be worked after it hardens.

 

[mhardy6647]

Bondo, an unusual product to use for dampening? It does become very hard after fully cured but I imagine a nice thick application would have positive results if from nothing else than it[]s pure mass.

Adding lots of mass and rigidity (baffling) definitely helps the ringy Altec horns, as does crossing over well above their nominal cutoffs - I think 1k will help with both the 811 & the 511.

 

[mhardy6647]

I wrapped my old Klipsch LaScala's with something that I can no longer remember.

Many, many layers of thick blankets might be helpful.
Face-down placement of LaScalas is always a plus - unless they can be placed in someone else's domicile entirely.

 

[Sal1950]

Perhaps that's not a good thing. Klipsch's horn designs have crystallised in time.

Not quite, there have been a number of changes & improvements to the crossovers and drivers over the years. The math on the big horns was done long ago and hasn't really changed over the decades. I haven't found any solid info on the changes to the big K-Horn that make up the AK6 upgrade, whats avalable is all pretty vague.

 

[Sal1950]

Many, many layers of thick blankets might be helpful.
Face-down placement of LaScalas is always a plus - unless they can be placed in someone else's domicile entirely.

Bah Humbug
Truely amazing speakers in many ways.

 

[MakeMineVinyl]

Adding lots of mass and rigidity (baffling) definitely helps the ringy Altec horns, as does crossing over well above their nominal cutoffs - I think 1k will help with both the 811 & the 511.

I've been all over the map with crossover frequencies with my A7-500s. When I worked as an engineer at Altec in the late 70s / early 80s, the 'official' factory crossover frequency for the A7 series was 1,200Hz. By this time, they were spraying the exterior of their 511/811 horns with Aquaplas to address the ringing - I don't think there are many of those Aquaplas treated horns still in the wild because Altec went belly up in Anaheim shortly thereafter. I tried crossing over at 1,200Hz, but the LF horn / driver gets kind of ugly up that high. I use the 'stock' 500Hz because of this problem with the LF horn, and because I like the extra projection and sense of 'there' from the range above 500Hz coming from the HF horn. Crossing over at 800Hz sounds sort of in the middle between the two and frankly sounded kind of boring, so I stay with 500Hz.

 

[mhardy6647]

Bah Humbug
Truely amazing speakers in many ways.

Definitely amazing.

 

[egellings]

A bass horn would be awesome, but would be unmanageably large if you want to get down to 30 Hz or so. I recall seeing a picture of such a horn in which an entire wall of the house was open and comprised the horn's mouth, and the exponential horn went way back into the yard, with a little dog house behind it holding the driver setup. Somehow, the name Ed Blount comes to mind when I think about it. It was outrageously preposterous! Loved it!

 

[tuga]

A bass horn would be awesome, but would be unmanageably large if you want to get down to 30 Hz or so. I recall seeing a picture of such a horn in which an entire wall of the house was open and comprised the horn's mouth, and the exponential horn went way back into the yard, with a little dog house behind it holding the driver setup. Somehow, the name Ed Blount comes to mind when I think about it. It was outrageously preposterous! Loved it!

These are quite radical.

 

[egellings]

Whew!

 

[Sal1950]

These are quite radical.

I want one, or two.

 

[Ro808]

You have chosen wisely
Is the woofer a 515B or a 416 family member? Looks like the former.
What treble driver are you using?

Gratuitous and unsolicited tip (sorry!). Consider losing that 811B (or is it a 511B?) and swappin' in an EMILAR EH-500-2, EMILAR throat adaptor, and an 802D driver.

DSC_6853 by Mark Hardy, on Flickr

The EH500 is indeed a much better horn compared to the Altec 511/811 family, not only in terms of material properties (it doesn't ring), but also because of the horn path.

As can be seen, not much gets in the way of the wavefronts emitted by the driver, except for the circular to rectangular transition and a slight narrowing in the vertical plane.

If we compare the Altec 511B, several sources of interference can be identified:

• The interior of the throat section isn't exactly smooth, but it also ends in a diffraction slot, which is a source of astigmatism and higher order modes.
• Beyond the slot, the wavefront is allowed to expand rapidly, though only in the horizontal plane. The vertical plane is constricted - after initial expansion in the throat section, which gives rise to additional distortion.
• Finally, the length doesn't improve things either.

 

[mhardy6647]

yup. The above reflects my understanding, from a couple of thorough discussions on the merits of the EH500-2 elsewhere.
Do we know each other from... Elsewhere, @Ro808 ?

 

[Ro808]

Perhaps from diyaudio, hifihaven, or wbf.

Someone made a CAD model of the EH500-2, making it possible to modify the horn for 1- or 1.4-inch drivers,
eliminating the need for a throat adapter.
Given the size of the EH500, I would only use it in combination with a 1" driver.
Starting point for modification could be the narrowest part in the horn mouth, subsequently morphing the remaining section towards the throat to 1".

However, I think much better horns have been developed, although not all of them are commercially available yet.

 

[Ro808]

Rendering will improve by eliminating the ringing. Nevertheless, it remains a sub-optimal horn, due to the previously indicated imperfections.
Which doesn't mean it's unlistenable.

This is the horizontal directivity sonogram of a contemporary take on the radial horn theme, so somewhat similar to the 511/811B and EH500-2.

 

[MattHooper]

Bah Humbug
Truely amazing speakers in many ways.

I'm with you there Sal.

Dunno if I'd live with the La Scalas myself, but now that they are gone from my friend's house (where I listened several times) I'm already missing them.

 

[MakeMineVinyl]

Rendering will improve by eliminating the ringing. Nevertheless, it remains a sub-optimal horn, due to the previously indicated imperfections.
Which is not to suggest that it's unlistenable.

Gee thank you for at least giving my speakers that much credit. But since you seem to be designing a competing horn, might you be guilty of at least a wee bit of bias?

 

[Ro808]

Not exactly competitive, as this is not a commercial product. Besides, the 511 and 811 have long been out of production.

Don't get me wrong, I'm a big fan of the Altec & Western Electric legacy.
Nor do I belong to the category that believes that (all) modern equivalent products are better.
However, horn science has progressed over the past 70 years.

 

[Thermionics]

Good choice (re: the 511).
I'd love to stumble across a nice (ahem, and affordable) pair of 414s.
I would do this (or something like this)...

Altec 753C

jelabs.blogspot.com

As Mark knows, I'm running a variant of these at home, and I think a large part of the magic is that the 414 runs up to ~ 4k and the 802/808 isn't brought in until 3k, so you are basically running the full range of most instruments (other than the bottom octave) on just the 414.