"Can't Do 3D Like Other Technologies". Fair Criticism of Horn Speakers?

jdza

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May 3, 2010
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I never meant to suggest every person doing this is likely to destroy their driver if they open the back of the compression driver. I only meant to caution that it does significantly change the behavior of most drivers. If you are using 5-25W amplifiers on passive speakers, it's highly unlikely you could cause damage in even the worst case examples. It could create some significant changes in a passive crossover response, especially near and below the intended crossover. I recall both product examples more looking to the benefits of eliminating rear chamber confinement and resonances, with any rear driver output being a modest benefit. The intensity difference from the front vs rear will depend a lot on the horn type, angle, and size. The more loading and gain provided by the horn, the bigger the difference will be.

In the case of the impressive horns you showed pictures of, I would expect a greatly reduced output from the back side of the driver vs from the horn. Opening the back of the driver in your case likely reduced some chamber resonances and lowered the resonance of the driver. It appears the horn you have is much deeper and loads lower than the 2393, which is why the bulk of the impedance peak is much lower, but the rear of the driver removed likely shifts that peak lower as well as reducing chamber resonances. Both changes would be likely to contribute to the subtle benefits you described in an earlier post.
Thank you for a detailed response and making engineering and science from what to me was little more than a whim and maybe based on the odd report here and there.

In the days when the Audio Asylum High Eff forum was brimming with knowledgeable folk, there was one of the highly regarded inmates who had a near-legendary bipole horn system using ElectroVoice drivers. This was never discussed and only mentioned in passing by others. Maybe Duke remembers who or what it was?
 
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Duke LeJeune

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Jul 22, 2013
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Thank you for a detailed response and making engineering and science from what to me was little more than a whim and maybe based on the odd report here and there.

In the days when the Audio Asylum High Eff forum was brimming with knowledgeable folk, there was one of the highly regarded inmates who had a near-legendary bipole horn system using ElectroVoice drivers. This was never discussed and only mentioned in passing by others. Maybe Duke remembers who or what it was?

I don't remember the system you describe, and haven't been able to find it (yet). But you've got me curious!! Could it have been Magnetar?

I've been manufacturing bipolar and other polydirectional hybrid horn systems since 2007 and don't recall seeing any other manufacturers doing it, but wouldn't be surprised if DIYers had tried it long before me. There's not much that DIYers haven't tried.
 

jespera

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Jan 12, 2018
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Jdza, your system is just stunning. I shake my head in awe every time I see a picture of it.

I use rear-firing drivers which cover quite a bit of the spectrum, which is apparently what you are doing. Likewise my drivers are fairly directional, and are usually aimed in a direction which results in a fairly long reflection path length involving wall bounces (not many people have a bass horn handy!). Imo we do not want this additional reverberant energy arriving early, and in this context "early" would be "within less than ten milliseconds of the direct sound". So the rear-firing energy might be directed upwards and backwards, such that it bounces off the wall and then off the ceiling before arriving at the listening area. If the speakers are also toed-in aggressively (as I normally recommend), the path length for the rear-firing energy is further increased.

Here's an example, tucked into a notch on the back of a fairly large floorstander:

View attachment 71907

Below is another example, this is the back of a speaker stand. The driver on the top of the notch is a subwoofer and the one on the bottom of the notch is a coaxial which is dedicated to the reverberant field:

View attachment 71910

The holes on one side of the notch - the "bubbles" - prevent a cupped-hands coloration from sound bouncing side-to-side within the notch.

The top-end response of the rear-firing drivers is user-adjustable, as is the overall volume level, for tailoring to the specific room conditions. We have found that there's a "sweet spot" as far as how loud the rear-firing drivers are, relative to the front-firing ones. Above a certain threshold, clarity starts to be degraded.



Rear-firing tweeters dedicated to the region north of say 10 kHz can help by adding a bit of reverberant energy which is normally missing because of tweeter beaming. But ime the actual effect on ambience is usually pretty small... ime the main benefit of a very high frequency rear-firing tweeter is an improvement in inner detail and timbre and naturalness.

Just thinking: would it make sense to point the rear firing horn towards a scattering (bumpy diffusive) surface? The idea of this would be to simulate cave acoustics. Ie many scattered small beams of sound that bounce on the surfaces of the room. Arriving delayed enough not to mess up the direct sound.

Jesper
 
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Duke LeJeune

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Just thinking: would it make sense to point the rear firing horn towards a scattering (bumpy diffusive) surface? The idea of this would be to simulate cave acoustics. Ie many scattered small beams of sound that bounce on the surfaces of the room. Arriving delayed enough not to mess up the direct sound.

I haven't tried that, but it sounds like a very good idea to me.
 
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jdza

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May 3, 2010
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I don't remember the system you describe, and haven't been able to find it (yet). But you've got me curious!! Could it have been Magnetar?

I've been manufacturing bipolar and other polydirectional hybrid horn systems since 2007 and don't recall seeing any other manufacturers doing it, but wouldn't be surprised if DIYers had tried it long before me. There's not much that DIYers haven't tried.
I've got it! The answer is 58, not 42. That is the age one where one can remember trivia you read yonks ago but not where you put that banana plug you had seconds ago.

Paul Eizik .

From the Audio Asylum

Bruce, I thought you'd know batter than to wrongly use the term "direct radiator" the way HT magazine writers do.
I've only seen and heard one dipole system that wasn't a direct radiator, Paul Eizik who hangs at the HE asylum has a giant dipolar horn rig with EV components. Imagine a Maggie but with huge balls.
EV also makes a dipolar compression driver though that's not what Paul uses.
 
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Duke LeJeune

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Paul Eizik .
Thank you!!

This might be it, photos in the first post on this page, posted by Tom Brennan:


My recollection is that Tom was associated with Bruce Edgar for a while and presumably had horns, then at some point he moved and downsized to Martin Logan electrostats.
 
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jdza

Well-Known Member
May 3, 2010
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Thank you!!

This might be it, photos in the first post on this page, posted by Tom Brennan:


My recollection is that Tom was associated with Bruce Edgar for a while and presumably had horns, then at some point he moved and downsized to Martin Logan electrostats.
Thanks!

All I had ever seen was that one post. The power of words. I had somehow envisioned these enormous bat-like full range EV horns firing from and back. It is, after all, not much different from what we are both doing. Yet we were totally unaware of others' implementation. If we all, independently, came to the same conclusion does that validate the approach?
 

jespera

Well-Known Member
Jan 12, 2018
144
95
95
Copenhagen
Thank you!!

This might be it, photos in the first post on this page, posted by Tom Brennan:


My recollection is that Tom was associated with Bruce Edgar for a while and presumably had horns, then at some point he moved and downsized to Martin Logan electrostats.

Love the picture. Ladies are crazy about stuff like that. Must be difficult to build two that look the same.
 

carolus

Well-Known Member
Dec 20, 2013
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Belgium (Brussels)
Thanks!

All I had ever seen was that one post. The power of words. I had somehow envisioned these enormous bat-like full range EV horns firing from and back. It is, after all, not much different from what we are both doing. Yet we were totally unaware of others' implementation. If we all, independently, came to the same conclusion does that validate the approach?
Probably ....the same (subjectif) "impressions" ...
&
I admire his quick (clever) fabrication and certainly the "passif cross-over" .... to the point.
It's music ...
Karel
 

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