What's the advantage of bass horn?

[drobskyk]

Hi, it's me again

As you know there are lots of horn speakers with a direct-radiating,rather than horn-loaded, driver for lower frequencies. They can also reach the efficiency up to 107dB, and are claimed to be able to be well driven by triode amps with a few watts. Frankly I like the design of K-horn, but what's its real advantage over others?

Thanks!!!

[WMcD]

PWK's thesis was that efficency is the key to lack of distortion.

One of his "proofs" was that diaphragm motion leads to Doppler distortion. As you may know, the Doppler effect is heard when a train is approaching. The pitch of the whistle is higher than actual. When the train is moving away, the pitch is lower. You hear the rapid change of pitch as the train goes by.

By analogy, a bass radiator diaphragm may be reproducing a bass note at 50 Hz (F1) and a higher note of say 200 Hz. If the diaphragm moves in accord to the bass note. It is the train. The diaphragm moves closer to the listener and away. The pitch of the F2 note changes.

Overally, you get new "notes" at F1 plus and minus F2 and F2 plus and minus F1. These are not harmonics. Rather they are intermodulation.

The only thing to do is to reduce the motion of the bass radiator. It has to be make more efficent.

One way is to use a sophisticated megaphone. We know megaphones work to make one's voice "louder". But actually it is a matter of efficency. In a simply explanation, the diaphragm can push more air when there is a megaphone in front of it. The sophisticated megaphone is, of course, an exponential horn.

As you point out, there are units with treble horns and direct radiators, aplenty. In many instances the bass radiator system is darn good.

To my ear, many such combinations don't quite sound correct. Dr. Bruce Edgar has remarked that he finds the same. He suspects that our ear-brain combination detects the intermodulation and to some extent ignors consistent intermodulation distortion. A full non horn system sounds well integrated. A full non horn system sounds well integrated. But the hybrid is not quite "there."

Before anyone dumps on me, let me say that I love my Forte II, which is hybrid system.

None the less, a set of K-Horns have a wonderful sound which is striking, and quite unique to full horn loaded systems. This sound is also exhibited by other big bass horns, most of which are out of production. E.g. the EV Patricians and JBL Hartsfields. Tannoy make the Westminster which is also horn loaded in the bass, though a different design. I haven't heard them, but folks do hear something unique.

The reports of listeners are subjective and people search for words. Clarity of sound is always acknowledged. The words of "effortlessness" and ability to hear "inner voices" (of music) are common, and consistent with my experience.

If you have a chance to hear a pair of K-Horns, you should, and I think you'll agree.

Edit: And I should add that the smaller bass horn systems like the LS and Belle have the same qualities. Still, the K-Horn has the lowest bass and, at least to me, this makes a difference.

Gil

[jdm56]

Hi Drobsky -

I think acoustic efficiency is still the #1 advantage sited for horn loading a woofer. I personally don't know of any non-professional speakers using direct-radiating cone woofers that achieve 107db sensitivity. I'm not contradicting you; but I just don't know of them. Some Cerwin-Vegas quote a very high sensitivity spec. (and for that matter, Klipsch' own designs, such as the Cornwall, Chorus, KLF's, etc.) BUT, (and correct me if I'm wrong here), none achieve the 104db spec. the fully horn loaded Klipsch designs do. And again, I may be off the track, but I believe the horn loaded woofers of PWK's design require less driver excursion to achieve a given spl than even similarly rated non-horn loaded designs. And less driver excursion translates to lower modulation distortion, i.e, "faster" bass. Perhaps someone more technically proficient will set me straight on that assertion, though. (I'm not an expert; I just play one on the internet.)

[Ray Garrison]

JDM -

107dB with direct radiating woofers.

Avantgarde Trio at www.avantgarde-usa.com

Main disadvantage - somewhat expensive at $40,000 the pair (with the smaller subwoofer option - for the truly obsessed woofer maniac, check out this thread...

Big Subs

[sunnysal]

I know these speakers are all the rage right now, but I had a chance to hear them in the NYC showroom and thought the integration with the Bass was rather poor, in truth, I liked my k-horns better. these were very "hifi" sounding almost too much for my backwoods ears. what did surprise me was that the bass didn't work for me on them AT ALL. PWK did it right...tony

[drobskyk]

Gil,

Quite a lesson for me, very informative.

Thanks!!!

[drobskyk]

JDM-

For your reference:http://www.jkaudio.com.tw/english/jktad/sl-01.htm

[TBrennan]

Ray---The Avante-Garde claim of 107db is for the horn-loaded portion of the speaker and not that small direct-radiating sub. No way a box that small and with it's claimed f3 can have high efficiency, no way.

My dual direct-radiating JBL 4648s, a total of 4-15s, have an efficiency of 106db running their natural f3 of about 45hz. That's a total of 16 cubic feet of cabinet. But the 6db of EQ used to extend the response flat to 25hz reduces efficiency overall to 100db.

www.chicagohornspeakerclub.org

[J M O N]

The AG speakers that use direct radiator subs are actually active subs - meaning, there is a built-in amplifier driving the bass drivers. So, technically, the subs really don't have that 107 dB efficiency. The gain on the built-in amps are just set to match the output of the horn drivers. I could be wrong, but I don't think there is a direct radiating woofer that has a 107 dB efficiency. Since the AG bass modules are not horn loaded, they don't exhibit the advantages of horn-loaded speakers (dynamics, clarity, output, etc.).

I have heard the Unos, and while they do sound good, the bass just doesn't compare with a Khorn IMO.

The reason for having horn-loaded bass is the same for having horns in general -- you get higher efficiency, lower distortion, superior dynamics, and higher output in the bass portion of the sound.

[TBrennan]

drobskyk----I'm wondering if basshorns really have any advantages. A basshorn gives reduced distortion for a given output because it reduces cone excursion, there's no denying that. But for a given f3 a basshorn can be very large, large enough that one must consider multiple direct-radiators. Several DRs can match the horn's eficiency and low distortion, several DRs having less distortion than one because the excursion is low. And not take up any more room than a basshorn.

On the other hand the basshorn only needs a single driver instead of 4 so driver cost is cheaper. But for the horn cabinet cost is more expensive. Take your pick. Both basshorns and large arrays of efficient DRs can do the job of providing large amounts of clean bass. So I reckon there's no hard and fast answer here.

www.chicagohornspeakerclub.org

[drobskyk]

TBrennan,

I know the advantage(and power) of multiple DR's(thinking of the bass tower of Genesis I), but the phase discrepancy of the drivers is always a problem, isn't it? Of course I thinnk the ear will be the judge.

Thanks!

[pzannucci]

I think TBrennan has it right, there are tradeoffs.

Horns were created when speakers were needed to work with low power equipment. Now with hi-power and multiple drivers have come about, horns are not necessarily needed.

The issues of phase and timing delays will be inherent in a multiple driver horn, much worse than a reasonably designed direct radiator.

Doppler effect is much less likely to occur when a driver is run in its preferred frequency range and will likely not be able to be heard as distortion. There are many fine 2 way systems that will be cleaner than K-horns or La Scalas so doppler effect could be deemed inconsequential unless driver excursion is very high with very small drivers. Yes it does exist but is it audible at normal listening levels?

Although I do agree generally that I prefer the sound of a horn loaded bass section (even with the distortion added by the horn). It really ends up just being your ear and how the system sounds AS A WHOLE sounds. It doesn't matter what the technology is, just that the system is relatively clean blends from top to bottom. I find that the synergy between the components has to be there otherwise you only listen to a narrow portion of the music and don't grasp the whole presentation.

My opinions of course...

[jdm56]

Hi Ray,

WOW, that A-G rig was some set-up. I couldn't believe how close the couch was to all that hornage, though. (can you say "horn glare"! My gosh, you could drive that thing with half a watt!

drobskyk,

Thanks for the link. It seems that there are many (well heeled) Asian audiophiles who appreciate big, high-sensitivity speakers. They'd no doubt feel right at home here on the klipsch forum.

All,

I guess I really wasn't thinking about the extreme high-end, when I said I didn't know of any speaker designs that utilized horn mid and/or tweeter drivers, with direct radiating woofers, that exceeded the klipschorn/belle klipsch/la scala sensitivity. Of course, that big A-G rig was (I think) fully horn-loaded, right down to the subs. And that big godzilla of a speaker that drobskyk provided a link to is not available here in the good ol' USA. Also, as has been mentioned (TBrennan?), the A-G's use of a powered, eq'd bass section kind of put's them in a different category.

But, come to think of it, there are some other ultra expensive, high sensitivity hybred horn/cone designs available here. The big Westlake Audio speakers come to mind.

But when you consider the that PWK gave us his designs at prices that virtually anyone with a decent job could afford, it makes them all the more amazing. Arguably, world-class performance at real world prices. Thanks, Paul!

[sunnysal]

AMEN!