I think the problem with crossing small drivers low is not that they will break, but that they start producing a lot of distortion.
Here's a measurement of the recent horn I 3D printed. Amplitude vs THD.
Now I'm not sure if this rise of distortion could be related to the material property of the horn (the actual horn ringing below 600)
Or if the increase of THD is a result of the decrease in gain below 700
Here's a measurement of the recent horn I 3D printed. Amplitude vs THD.
Now I'm not sure if this rise of distortion could be related to the material property of the horn (the actual horn ringing below 600)
Or if the increase of THD is a result of the decrease in gain below 700
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Antique Altecs somewhat modernized from new tooling for home or prosound:
http://greatplainsaudio.com/wp-content/uploads/2016/06/902series-1.pdf
http://greatplainsaudio.com/wp-content/uploads/2016/06/909series.pdf
Did you also measure distortion of the other horn, the deeper one with slot?
You may want to check the diaphragm + coil for damage and the gap + mounting plate for dirt. Assuming you've got a pair, you can try the other driver.
I've used the 4554 (the 1.4" version of the 4550) with the XT1464 from about 900 Hz. Distortion did increase below 800 Hz, but more evenly.
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Is there any pricelist for the Great Plains Audio drivers?
Edit: Just found here: Products – Great Plains Audio - a bit on the expensive side as expected.
Edit: Just found here: Products – Great Plains Audio - a bit on the expensive side as expected.
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The Altec drivers are pretty nice, but for a single GPA 802-8 you'd buy a pair of high-end drivers that can cover 500-20,000 Hz. Besides, the long snouts of the Altecs (similar to the TAD TD2001) are designed for exponential horns and won't work as well with waveguides.
That said, I still regret missing out on a pair of working 802s + vintage Ciare horns that were offered for € 25, years ago. At the time I didn't immediately recognize the drivers because instead of the usual decals there was only a serial number on the back covers. When I found out they were Altecs, they were gone.
The Ciare horns in question, clearly different from the average ATH4 horn.
That said, I still regret missing out on a pair of working 802s + vintage Ciare horns that were offered for € 25, years ago. At the time I didn't immediately recognize the drivers because instead of the usual decals there was only a serial number on the back covers. When I found out they were Altecs, they were gone.
The Ciare horns in question, clearly different from the average ATH4 horn.
Attachments
So what does it mean, an "average ATH4 horn"? Tell me, show me. I don't know what it means. Do you? Does anyone know?
Frankly, I'm getting tired of all this nonsense.
BTW, acoustic waveguides, when the term originated, were a clear distinction as a well-defined subset of general horns. You should look it up.
Frankly, I'm getting tired of all this nonsense.
BTW, acoustic waveguides, when the term originated, were a clear distinction as a well-defined subset of general horns. You should look it up.
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2nd paragraph from Dr. Geddes' document "What is a waveguide?":
"It should be obvious at this point that all waveguides are horns, but not all horns are waveguides."
Then:
"The difference is if the directivity of the device can be analyzed analytically or not. If the directivity cannot be analyzed then the device cannot be said to be designed for directivity control. This is why it is sometimes said that waveguides are used to control directivity, but horns are used for loading. There is some truth in this, but it’s not completely correct either."
From your website:
Advanced Transition Horns
by Marcel Batík
Ath - The generator of state-of-the-art acoustic waveguides
In the context of my post, I wanted to clearly state the difference between the vast majority of waveguides and horns generated to date using ATH4 versus the exponential Ciare horn in question, and compression drivers with a snout / long conical exit section.
And yes, I know you can design almost any horn/waveguide imaginable using your tool...
But that's beside my point.
And I end with a comment of a general nature.
The last thing the world needs right now is more competition and division.
"It should be obvious at this point that all waveguides are horns, but not all horns are waveguides."
Then:
"The difference is if the directivity of the device can be analyzed analytically or not. If the directivity cannot be analyzed then the device cannot be said to be designed for directivity control. This is why it is sometimes said that waveguides are used to control directivity, but horns are used for loading. There is some truth in this, but it’s not completely correct either."
From your website:
Advanced Transition Horns
by Marcel Batík
Ath - The generator of state-of-the-art acoustic waveguides
In the context of my post, I wanted to clearly state the difference between the vast majority of waveguides and horns generated to date using ATH4 versus the exponential Ciare horn in question, and compression drivers with a snout / long conical exit section.
And yes, I know you can design almost any horn/waveguide imaginable using your tool...
But that's beside my point.
And I end with a comment of a general nature.
The last thing the world needs right now is more competition and division.
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Is there anyone able to tell me what the term "average ATH4 horn" supposed to mean or not?
Am I asking too much when I want people to use meaningful terms in a technical discussion?
- So, was it supposed to mean a "vast majority of waveguides and horns generated to date using ATH4"? OK then, let's call it an average ATH4 horn, whatever that means.
Am I asking too much when I want people to use meaningful terms in a technical discussion?
- So, was it supposed to mean a "vast majority of waveguides and horns generated to date using ATH4"? OK then, let's call it an average ATH4 horn, whatever that means.
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That's a definition of a subset, right, as I said. But I have no clue why you brought that up. I use the terms mosty interchangeably, as only a few people today still understand the difference anyway. I could well use only waveguides, I guess.
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Marcel deserves naming rights as a courtesy. Without a mathematical, logical mindset ATH never would never have been born. Is it too much to require equal precision in choice of words?
As young engineers, myself and others of similar mindset couldn't help ourselves from pointing out logical inconsistencies in other's speech. Needless to say we failed to change anyone's manner of speaking ... but the process was enjoyable until we outgrew it. Now, I'm equal parts embarrassed and amused those few times I am caught out in a logical inconsistency.
Here we would benefit from agreeing on a term to use to refer to what results when Ath is used correctly and well. This would not be a matter of precision in speech but simply a definition. Having started as I did, it would be inappropriate for me to propose such a term.
As young engineers, myself and others of similar mindset couldn't help ourselves from pointing out logical inconsistencies in other's speech. Needless to say we failed to change anyone's manner of speaking ... but the process was enjoyable until we outgrew it. Now, I'm equal parts embarrassed and amused those few times I am caught out in a logical inconsistency.
Here we would benefit from agreeing on a term to use to refer to what results when Ath is used correctly and well. This would not be a matter of precision in speech but simply a definition. Having started as I did, it would be inappropriate for me to propose such a term.