A different look at horns vs direct radiators???

[DrWho]

I dunno what I'm gonna do.

To be honest, I know what the vented cabs will do, but I'm worried about screwing up the horn and I'm not sure I can guarantee outperforming the vented cab (unless I go rediculously huge with it).

[ZAKO]

VOT anyone?

[Don Richard]

I'm not sure I can guarantee outperforming the vented cab (unless I go rediculously huge with it).

Most commercial manufacturers of small to medium point and shoot sound reinforcement systems have gone to vented cabinets for that very reason.

[John Warren]

What's always bothered me about the Klipschorn is that the bass horn, operating alone sounds like sh*t when compared to a DR woofer operating over the same bandwidth. Yes, it is far more efficient (alot louder) but speech is unintelligible whereas speech IS intelligible in the DR woofer. And yes, this is a qualitative test BUT it is what it is.

Thus, I always have the little birdie reminding me of the EFFICIENCY- BANDWIDTH (ie. transient behavior) tradeoff. The fix is a good one but means bye-bye to the mid horns.

[boom3]

If you read the Augsperger paper posted here recently, and then re-read Paul's original K-horn paper, a light slowly comes on. Bass horns are not horns near, or below nominal cut-off. They are Something Else. What is that Something Else? Is it a T/L?

We used to accept this statement as an article of faith:

"With a corner horn, the listener sits inside the horn, which is formed by the walls and floor of the room, so the room completes the horn"

We now know this just ain't so. The horn ends where the physical structure ends, but the images of the horn assist the response. It is more accurate to say:

"A corner horn will energize all available room modes (eigentones) and make the optimum use of the room's capabilities in the bass region".

[djk]

"What's always bothered me about the Klipschorn is that the bass horn, operating alone sounds like sh*t when compared to a DR woofer operating over the same bandwidth. Yes, it is far more efficient (alot louder) but speech is unintelligible whereas speech IS intelligible in the DR woofer. And yes, this is a qualitative test BUT it is what it is. "

And if you run a steep low-pass filter on both, the DR will sound a lot more like the horn (but with more distortion, etc).

I still suggest going three-way, horn loaded above 150hz ~250hz.

[ClaudeJ1]

didn't know that horns were freq band sensitive. this is where bruce and i disagree.

take care,

roy

Yes. Not that I have any measuring experience in a chamber, but why he claims it works for mid and not bass? Is it the nature of the compression driver vs. the woofer? What's the difference?

[ClaudeJ1]

I dunno what I'm gonna do.

To be honest, I know what the vented cabs will do, but I'm worried about screwing up the horn and I'm not sure I can guarantee outperforming the vented cab (unless I go rediculously huge with it).

Why don't you just build a couple of Tom Danley's LAB horns? You could do that for less than $1,000/pair and they get to 30 Hz with 106 db efficiency in a 16 cubic foot enclosure.

[ClaudeJ1]

"What's always bothered me about the Klipschorn is that the bass horn, operating alone sounds like sh*t when compared to a DR woofer operating over the same bandwidth. Yes, it is far more efficient (alot louder) but speech is unintelligible whereas speech IS intelligible in the DR woofer. And yes, this is a qualitative test BUT it is what it is. "

And if you run a steep low-pass filter on both, the DR will sound a lot more like the horn (but with more distortion, etc).

I still suggest going three-way, horn loaded above 150hz ~250hz.

This is the direction I'm going..........the 10-12" driver/large midbass horn to replace the LaScala bottom. I want to go from about 250-1,000 Hz. with a straithg axis (not folded) horn. The get on with the treble section........possibly a 4 way if the EQ for the upper mid horn won't get me enough air above 5Khz. Do you know anything about a Peavey MB-1?

Anyone want to buy two MWMs bins?

[Deang]

Top secret where I got this.[:'(]

What's the big secret? It's from the Positive Feedback interview done by Dave Glackin.

http://www.volvotreter.de/downloads/The%20Edgar%20Interview.pdf

[bodcaw boy]

What's always bothered me about the Klipschorn is that the bass horn, operating alone sounds like sh*t when compared to a DR woofer operating over the same bandwidth. Yes, it is far more efficient (alot louder) but speech is unintelligible whereas speech IS intelligible in the DR woofer. And yes, this is a qualitative test BUT it is what it is.

Thus, I always have the little birdie reminding me of the EFFICIENCY- BANDWIDTH (ie. transient behavior) tradeoff. The fix is a good one but means bye-bye to the mid horns.

kill the bird....it's lying to you.[8-|]

take care,

roy

[sfogg]

"What's always bothered me about the Klipschorn is that the bass
horn, operating alone sounds like sh*t when compared to a DR woofer
operating over the same bandwidth. Yes, it is far more efficient (alot
louder) but speech is unintelligible whereas speech IS intelligible in
the DR woofer. And yes, this is a qualitative test BUT it is what it
is. "

When doing the comparison did you take into account that the folded bass horn acts like a low pass filter? If you didn't your comparison wasn't over the same bandwidth.

Shawn

[jwc]

Top secret where I got this.[:'(]

What's the big secret? It's from the Positive Feedback interview done by Dave Glackin.

http://www.volvotreter.de/downloads/The%20Edgar%20Interview.pdf

There is no secret Dean. That line was a goof man. I know no top secrets (at least in audio).

jc

[DrWho]

We used to accept this statement as an article of faith:

"With a corner horn, the listener sits inside the horn, which is formed by the walls and floor of the room, so the room completes the horn"

We now know this just ain't so. The horn ends where the physical structure ends, but the images of the horn assist the response. It is more accurate to say:

"A corner horn will energize all available room modes (eigentones) and make the optimum use of the room's capabilities in the bass region".

I'm not sure I entirely agree with that conclusion...

For starters, eigentones can only occur inside a room - which is a separate behavior from the effects of 1/8 space loading, which you can see if you have a large enough corner outdoors. But more importantly, the eigentones don't necessarily improve the low frequency extension - they're just standing waves and the listener will be in a null at some frequencies and peaks at others. It is going to be a very specific case to have a peak sitting at the F10 of your horn.

Besides, you really only start to see gains below the lowest eigentone, which is essentially the same effect as cabin gain in a car. The way I understand it, the wavelengths are long enough that the "ambient" pressure at the mouth of the horn increases, which in turn improves the impedance matching - and thus you get more output in much the same way as you get more output from having the horn in the first place. The same effect also happens with direct radiators (since radiating into that higher pressure improves its power transfer too). I've never actually measured it, but I would expect the room gains to be the same for both the horn and the direct radiator...or if anything, probably less gains with the horn since it has less room to improve (there is a maximum possible efficiency).

So all that to say, I agree more with the notion that the room's corners are redirecting power towards the listener, which in turn increases the intensity (SPL). Simply redirecting the power doesn't increase the efficiency of the system. However, having that energy redirected near the mouth of the horn causes there to be an increase in air pressure near the mouth, which in turn improves the impedance match and you DO see an increase in efficiency...you mostly see the increase at the frequencies that are matched more poorly, which is at all those dips you see in hornresp when the mouth is too small. I think this is also why the frequency response smooths out on bass horns when you've got a bunch of them sitting right next to each other (like you see all the time in PA scenarios).

[DrWho]

I dunno what I'm gonna do.

To be honest, I know what the vented cabs will do, but I'm worried about screwing up the horn and I'm not sure I can guarantee outperforming the vented cab (unless I go rediculously huge with it).

Why don't you just build a couple of Tom Danley's LAB horns? You could do that for less than $1,000/pair and they get to 30 Hz with 106 db efficiency in a 16 cubic foot enclosure.

I am trying to reuse the four JBL2226J drivers that I'm tearing out of the beat up vented cabs.

The Lab Horn is designed for the Eminence Lab12 (12" driver) and requires something like 4 cabs side by side to achieve usable output to 30Hz. Is that the one you're talking about?

[DrWho]

kill the bird....it's lying to you.

I can never remember which one to call...

http://www.peta.org

or

http://www.mtd.com/tasty/

[A]

[John Warren]

When doing the comparison did you take into account that the folded bass horn acts like a low pass filter? If you didn't your comparison wasn't over the same bandwidth.

Both you and djk are telling me to make an apples to apples comparison and both of you are correct.

I'm looking at it differently, more from a "what's the point of all this complexity", bear with me.

If you look at the anechoic response of the Klipschorn bass unit, it's Mt. Everest with it's summit positioned around 200Hz. So Bodcow Boy comes in with his big-gun notch filter and flattens it in the AK-5(?) network. In the process he throws away very, very hard earned dBs (after all why make all these compound angles and complicated wooden panels if, in the end you throw them away?)

OK, Bodcow Boy then tells me that the Birdie is a lying bastard. BUT he just threw away dBs (efficiency) with the notch filter because his horn is a low pass filter that increases the SPLs of the amplitude response of the driver over a relatively narrow bandwidth (peaky response).

So I ask the question "did he throw enough dBs away such that I can now come along and mount two K33s in a vented cab and give his notch-filtered bass unit a run for it's money? For example, (forget K33s) can I go out and get a couple of, say, McCauleys at 96dB/W/m and put them in vented cabs, two per side and I realize 99/W/m from Fs to 600Hz?.

My question then is this--> is the single driver, low-pass, high efficiency unit a BETTER engineering compromise than the two (or multi) driver, all-pass(?) unit.

jw

[bodcaw boy]

When doing the comparison did you take into account that the folded bass horn acts like a low pass filter? If you didn't your comparison wasn't over the same bandwidth.

Both you and djk are telling me to make an apples to apples comparison and both of you are correct.

I'm looking at it differently, more from a "what's the point of all this complexity", bear with me.

If you look at the anechoic response of the Klipschorn bass unit, it's Mt. Everest with it's summit positioned around 200Hz. So Bodcow Boy comes in with his big-gun notch filter and flattens it in the AK-5(?) network. In the process he throws away very, very hard earned dBs (after all why make all these compound angles and complicated wooden panels if, in the end you throw them away?)

OK, Bodcow Boy then tells me that the Birdie is a lying ***. BUT he just threw away dBs (efficiency) with the notch filter because his horn is a low pass filter that increases the SPLs of the amplitude response of the driver over a relatively narrow bandwidth (peaky response).

i threw away sensitivity not effciency. did you fry up the birdie?

So I ask the question "did he throw enough dBs away such that I can now come along and mount two K33s in a vented cab and give his notch-filtered bass unit a run for it's money? For example, (forget K33s) can I go out and get a couple of, say, McCauleys at 96dB/W/m and put them in vented cabs, two per side and I realize 99/W/m from Fs to 600Hz?.

what about polar pattern, DI, tranformer action, and distortion?

My question then is this--> is the single driver, low-pass, high efficiency unit a BETTER engineering compromise than the two (or multi) driver, all-pass(?) unit.

no matter how efficient a DR is, it still has to move to create a certain amount of spl. and the more it moves, the more it distorts. unless........you just don't want to mess with the stupid horn. [8-|] then i agree, do the DR dude.

jw

take care,

roy

[Don Richard]

What's always bothered me about the Klipschorn is that the bass horn, operating alone sounds like sh*t when compared to a DR woofer operating over the same bandwidth. Yes, it is far more efficient (alot louder) but speech is unintelligible whereas speech IS intelligible in the DR woofer. And yes, this is a qualitative test BUT it is what it is.

So a direct radiator is superior to a Khorn because one can hear the breakup modes of the driver better in a DR enclosure? This can be construed as distortion and more distortion isn't better, at least not for me.

[Don Richard]

"A corner horn will energize all available room modes (eigentones) and make the optimum use of the room's capabilities in the bass region".

It is not the function of any reproduction transducer to excite standing waves in a room. This does happen despite best efforts.

"With a corner horn, the listener sits inside the horn, which is formed by the walls and floor of the room, so the room completes the horn"

We now know this just ain't so. The horn ends where the physical structure ends, but the images of the horn assist the response.

Actually, the mouth of a horn may be beyond the physical dimensions of the horn's enclosure. Designers of horns apply what some call end correction to account for the true mouth size of foreshortened horns. The particle velocity of a sound wave at the physical mouth structure is quite high, and in the case of the Khorn this wavefront curves around the front face of the enclosure creating a virtual horn segment large enough to cause horn loading to below 40 Hz.