Why not horns?

Well, alrighty then. Would anyone like a biscuit with their tea? I found the weather a little disagreeable this morning.

Unsound, I appreciate your last comment. It is where I was for many years, and to this day (and I expect for years to come) I still run into horn designs that are guilty of everything you mention in your first paragraph. When horns suck, they really suck. But like any technology, its all in the execution, and when you encounter good horns, they will lack most of the objections you have except size and maybe what it means to be ugly.

A special point with regards to

so sensitive that they amplify every minutia of noise and distortion

Really, every speaker must play every minutia of noise and distortion to be a good speaker, but the noise/distortion floor of electronics is definitely an issue with horns. When we first encountered customers with horns, I think we failed pretty badly on this point because our reference speakers at the time were 89 db. This forced us to really figure out how to get our noise and low level distortion floors down with the end result that we now build a much better product. That revealing nature is thus a boon to progress, but a bane if you have problems in the electronics.

O.K. Macrojack, I don't like horns because to my sensibilities the are honky, screechy, shouty, have a cupped coloration, are too big, can be so sensitive that they amplify every minutia of noise and distortion, are ugly, require a ridiculous amount of of space, get in the way of themselves in such a manner that time aligning them is next to impossible without the added expense of digital manipulation, image poorly, and due to the the exra needed labor to manufacture, the huge size, unusual shape and extra weight cost more than competing designs. IMHO, all told, horns offer an ugly sound for a very high price.

I offer my apologies for wandering off topic and mentioning other brands of speakers that don't offer horns. In my defense it was in response to other contributors that brought up the fact that current technology allows horns to now be time and phase coherent, something that was previously next to impossible to do. I applaud the effort. Another poster suggested that only one other very different speaker technology was capable of that. The inference was that horns are no worse than most in that regard. I thought it appropriate to point out that various other speaker designs offer that capability. Some of us find that important.

I feel that comments from the 60s 70s are still passed about as facts by many. Audiophiles have been told for decades that horns where not hi fidelity. Many audio reviewers from the past where anti horn. And much of there bias has been passed about as fact today. Note the all horns honk comments etc this BS is still passed about as a fact even in your thread. Getting over this wrongful bad press and bias. Much the result of AS designs and stereo coming out into the market. Many owned a horn speaker in a mono system,now with stereo and these new AS designs about they where told by the press and audio shops that horns are old fashioned and dated sounding. Since they could replace the 1 large horn with 2 smaller speakers many did so and denounced horns. But this is funny to me since the new AS designs from the late 50s 60s are not so collectible [AR Advents etc] but the old horns they shit canned sure are. Maybe that should say something about the performance of horns that even the old designs are relevant today. And some have values approaching that of new sports cars. Do not think the ARs that replaced the horns are worth more than a few $100 today. Seems this has gone on today with the slim tower these are cheap to build ship store pack etc very good at profits. But sound is so so from most such designs. But still the poorer performing tower is hyped as the best design for audiophile use. For HT we where told big speakers where not needed that small cubes suffice and are higher performing and many still believe this as fact. In our hobby most fall for hype BS Bias etc. Never really investigating for themselves. Easier to pass about others opinion and bias as your own and much easier too no thinking or work involved.

The last three posts seem to have wandered away from the subject of "Why Not Horns?". If there is relevance, I can't see it.
The brand names you guys are offering do not offer horns as far as I know so why are they being named? If you want to say something about why you chose a design that isn't horn based, you would be on topic and making a useful contribution but simply shouting out names we all know from the back of the room doesn't really help me answer my question.
I have used and enjoyed Sound Labs, Goldmund, Avalon, Magnapan, QUAD, Aerial Acoustics, NHT, Spendor, B&W, Zu, Vandersteen, and others over the years but these horns I use now provide a sense of "you are there" that my previous speakers did not arouse to the same degree, if at all.
Naturally, I'm not able to speak to "why not horns?" because I use them. Many of the respondents here do not like horns and I'm looking for reasoned explanations as to why not. Simply saying what you like or what another product does that you like does not really add to the discussion.
I am assuming that the majority have no real first hand experience with good horns and therefore no way to comment one way or the other. Some, however, have been pretty assertive about a dislike that has gone unexplained.

Personally I love my ribbons on my Apogees, they just sound right

Eldartford, I believe that some speakers from Dunlavy, Green Mountain, Quad, Vandersteen and Thiel can do a fairly good job of reproducing a square wave too.

Phase coherency, or lack thereof, is best evaluated by a speaker's ability to reproduce a square wave. The only speaker that I know of that does this well is the original full range Walsh driver.

Herman, I leave the design of speakers to someone else to prevent headaches. I was just pointing out that the crossover can be used to correct time alignment (sometimes this results in the need to reverse the phase of certain drivers as a result), and in fact a crossover will introduce some time alignment issues that might have to be otherwise addressed. I think its a bad idea to rely on that exclusively- doing some physical alignment is important too.

Phase shifts can occur because the drivers are different distances from your ears. This can be corrected physically with driver placement. That's one reason you see speaker boxes that slope back to get the tweeter voice coil aligned with the woofers. That's pretty easy to do or you can do the digital delay. If you look at various front loaded horns you almost always see that they are built with the mouths of the horns different distances away from the listener to align the voice coils.

The harder problem is phase shift caused by crossovers. In a simple first order crossover as you get close to the cutoff frequency you also start getting a phase shift. At the cutoff frequency there is a 45 degree phase shift. Different frequencies get shifted by different amounts. There are other filter configurations that have less or more phase shift but each is a compromise in some way.

I use a digital crossover and delay that they say has no phase shift but I tend to believe it must be screwing with the signal in some other way. I don't know enough about digital filters to prove that but I'm in the "you don't get something for nothing" camp.

.

Herman - Thanks, I needed that. Polarity and phase are different topics with different remedies. And polarity is fairly easy to diagnose and remedy. How about phase problems? What are the causes? How do you diagnose phase problems and how do you fix them?

Ralph, I'm glad we have found common ground on the horn issue after butting heads on single ended Vs. balanced, and I understand your point about phase shift in crossovers, but trying to do time alignment by phase shift in crossovers seems to me to be a hopeless affair. The amount of shift is frequency dependent so while I suppose you can shift a driver closer to another as you approach the cutoff frequency wouldn’t that leave you out of phase in the passband of each driver? I’m no speaker/crossover designer so maybe I’m missing something.

Macro, you are a bit off base on that one. It is one of the common misconceptions in audio. Your description of being physically aligned is correct but your description of phase and polarity isn't.

A difference in phase means a difference in time. A difference in polarity means one signal is going positive while the other goes negative. Phase and polarity are two entirely different things.

It is confusing because if you reverse the wires on one speaker (black to red) in a stereo pair then everybody says the speakers are out of phase. That is technically incorrect. The correct phrase is you have reversed the polarity to one speaker. One will be going in while the other is going out. They still happen at the same time so they are in phase but they move in opposite directions so they have opposite polarities. Unfortunately it is common practice to describe it as the speakers are out of phase, and it is awkward to say that one has its polarity reversed, so we are stuck with a phrase that is technically incorrect.

Same situation with balanced cables. While one line is going positive the other is going negative. Some people incorrectly say they are out of phase but actually one has inverted polarity.

If the speakers aren’t time aligned then there is indeed a phase shift, a difference in time.

.

Anybody know offhand if/how Klipschorns deal with time alignment?

Time aligned and in-phase are different issues. All of the drivers in a speaker could be mounted with their voice coils in the same vertical plane (time aligned) while one of the drivers is wired out of phase. So time alignment deals with physical relationship.
As explained by someone's post above, time delay can be adjusted to compensate when drivers are not aligned physically. Phase is another matter. It refers to the drivers all operating in unison electrically. This requires that all drivers are wired with the same polarity. As I understand it, a 6 db slope in the crossover causes a 90 degree phase shift. But from there I am lost. Who can explain this for me?

Phase can be adjusted to a fair degree in the crossover as well.

Mapman, the horns I listen to, as far as the soundstage is concerned, seem entirely recording-dependent as far was whether they are upfront or laid back. IOW they are neutral in this department. Some recordings will have sounds that seem inside the speaker. Others, the speaker seems to not exist as far as the music is concerned.

Herman,

That's a good point regarding time alignment.

Phase coherency is a must for good sound in my mind, yet this is the first I heard of it addressed in a horn design, yet horns would seem to be the most susceptible.

It would almost seem like a serious defect to not address it somehow when building horns to compete with other inherently more phase coherent designs?

Digital technology saves the day once again!

Herman thanks for the reply;something I never considered.

Herman, well said, no arguments from me.

Mapman, I see, then my horns are very laid back using your definition. IMHO this has everything to do with how speakers are place in the room and very little to do with the type of speaker. Don't let comments like those from Unsound dissuade you. You may not end up liking them but with 10s or 100s of thousands of us loving them they must have something to offer.

Rleff, Time align means that the sound waves from the different drivers arrive at your ear at the same time. Imagine a whack on a drum that was partially produced by the woofer and partially produced by the mid range and just to exaggerate imagine that the woofer is sitting 100 feet behind the midrange. You would hear the higher frequency part of the whack and then about a tenth of a second later hear the low frequency part of it. That applies to all speaker systems with more than one driver but it is exacerbated with a bass horn since they are so long.

In order to physically align my drivers the mid-tweet horns would have to be 16 feet behind the mouth of the woofer. I choose to digitally delay the mid-tweets instead of moving them.

Unsound, I guess that's why there are different types of speakers. I've never heard a Thiel I wanted to listen to for more than a few minutes. I've never heard the upper level Vandersteens but the 3A sounds to me to the slowest speaker in the world. I end up leaning forward trying to get to the music. Others say they sound wonderful. Go figure.

.

Devolution?

Unsound,

Yes I missed in reading first time that your reference was regarding horns.

You may be right. It would take a lot for me to live exclusively with horns I think, but I do find them intriguing, if not all that practical perhaps.

Luckily, I am blesed to have a house big enough to enable me to dabble when desired without having to say goodbye to what I have.

The bad news is my wife's sunroom is the room where I would most like to experiment with horns!

I've thought about it for a good while now but there are enough practical barriers to address that it has not happened, yet.

Someday I do predict there will be a set of horns in my house somewhere, even if it turns out to be just a nice looking old Victrola.

Mapman, I thought it was obvious that I was questioning the midrange purity of horns. Horns are about as different as omnis as can possibly be. Based upon your love of omnis, (which I do appreciate), I can't help but feel that horns would be an anathema to you. I find horns to be the most colored of all the different speakers. I will say that they do do dynamics and loudness as well or better than just about all other speakers (though the Wilson's can give them a run). If one were to listen to nothing but big band music, I could understand one choosing horns, but despite literaly hundreds of demos, including some high touted and expensive rigs, I find horns to be a bad joke.

"what do you mean by forward and laid back"

Laid back meaning the soundstage is mostly behind the plane of the speakers.

Forward meaning that the soundstage is not so much behind the plane of the speakers and some things may sound like they originate from locations that are in front of the plane of the speakers. In some lively rooms, due to reflections, sound might even sound like the origin is behind the listener to some extent.

I have heard both dynamic and planar designs have a quite forward sound in certain lively rooms, but not so much omnis. I expect horns might as well. granted, room acoustics play a big part in this.

I was wondering about some of the posts that mention time aligning of the horns;can anyone briefly explan this situation as I am not familiar in the setup of a horn based system.

I have my own ideas but what do you mean by forward and laid back? I would not describe my horns as forward. I would say the are transparent and very revealing so bad recordings are revealed as such.

.

Dan_ed,

Have you ever heard omnis like OHMs or mbl?

I believe setup can surely affect the tendency of a horn to be more forward or not, but I am not sure if I can envision them being as laid back as omnis I have heard.

And again, to me, a forward tendency is part of the attraction for me in taht I like to look at radically different approaches to achieving good results.

I also suspect though that along with a more forward presentation goes an increased chance to offend or irritate, but I do not think that this necessarily has to be the case and that is the sound that I would be interested in hearing.

Unsound,

Which approach's midrange purity do you question? Horn, Walsh or Walsh/CLS, or both?

If a single driver can cover most of the midrange with a flat response and have good dynamics, that to me would indicate at least the potential for midrange purity. Whether or not it is realized or not would depend on additional factors in each case though of course.

Mapman, as with any speaker driver one can change the presentation of horns. I have read man posts by horn users who prefer solid silver wiring. In some places I agree with them. However, I recently went through auditions of an interconnect cable that is made with solid silver wiring but comes with the option of copper or silver connectors. The silver connectors most definitely moved the musicians to the front and right into your face. The copper connectors, on the other hand, tended to move things back with a more relaxed presentation and that is the option I chose.

unsound, I assume you are generalizing? Yes, my horns do have midrange purity, and low and hi range purity as well. I'm sure we can all find examples of speakers of any type that do and don't have purity.

Midrange purity of horns? Ha! You can't be serious.

Johnk, do you have a link to that. I assume you aren't talking about the system you have posted here.

Here's a fresh question.

Are horns generally more forward rather than laid back sounding? is this always necessarily the case?

Reason I ask is that the Walsh drivers I currently prefer tend to be on the laid back side, in that most things happen behind the plane of the speaker in most setups.

That is the most distinctive characteristic of the omni Walsh driver I think. Other than tha, with my eyes closed, I believe I would be hard pressed to identify the driver technology used in that they have various characteristics of otehr driver types I have heard and read about, including the midrange purity of horns.

So part of the appeal of horns to me is that in my mind they represent the other end of the spectrum in terms of being more forward sounding than what I have. I'm not saying that is better or not, only different. I think what I have pushes things about as far as I would need to go in its direction, so horns appeal to me as a means of trying something completely different and comparing and constrasting. Were I to do it, I would also anticipate the need at some point to use a spearate amp for them from the rest of my system(s), probably a tube amp, in order to get the most out of them.

You do not need 35ft long horns. Herman I also have front loaded bass horn with 16ft horn path. You also have to consider the room if rooms right the bass horn can couple to floor ceiling to produce a even larger horn. I do this with all my horn designs.

I'll chime in regarding Klipschorns.
I had never heard nor seen a pair but decided to look to buy after becoming somewhat bored with my system over the past several years. I had Martin Logans and before that a couple of models of Maggies, Paradigms before that. I just thought it would be fun to try something completely different. I sold all my stuff, bought the KHorns the day I went to listen about a year ago and have been enjoying them since. I have a few SE amps to drive them. Sound is at least as good as what I had before, and even a bit cheaper ($2K for the KHorns, with less expensive amps).
KHorns (or horns in general) might not be for everybody, but they do work well. I'm sure I'll be playing Hi efficiency speakers and low power SE amps for a long time.

I love my Sansui sp-5500's MADE IN JAPAN! I had all the wires and crossover parts CRYOED

Macrojack, the folded horn you asked about is one of a thousand variations on the same idea. I can't speak to that particular model but as a general design it works pretty well if done right but has a few problems. You have parallel side walls which means you have resonant frequencies and it really doesn't flow like a what I would call a true horn. If you look at mine it is expanding in all directions as you go from driver to mouth so no parallel walls and no sharp bends like in a folded design. However, the folded horn is a good compromise.

Lokie, as you realize it is difficult to describe sound but the best I can think of is a box is muddy compared to a horn. Not that good subs sound muddy but horns are just a bit better. I think it is usually described as the horn is faster but I'm not sure what that exactly means. If you could hear one you would understand but unfortunately they are few and far between.

.

Can someone provide some general impressions regarding the difference between a horn bass, folded horn and a good modern sub woofer(s)?

Is the difference more sonic qualities, room loading or is it that only a horn can keep up with a horn?

I'm surprised there was no comment about the link I provided for a small DIY Tapped Horn design that is said to reach 25 Hz. in room. It's footprint is about 7 inches by 20 inches and it stands 30 inches tall. Here's the link again:

http://www.techfx.us/web/insubnia/Exodus%20Anarchy%2025hz%20TH.pdf

Klipschorns are pretty large and they reach down to about the mid 30 Hz. range. They are designed to be placed in corners so only certain rooms can actually accommodate them properly. The idea is for the walls running out from the corners to serve as extensions to the bass horn. It works pretty well. The K-horn can be found pretty cheaply used ($2500/pr.) and aftermarket upgrades to crossover, wiring, horns, drivers, connectors, etc. are widely available. There is much room for improvement in the original execution but the upside is very cost effective. Not a bad place to start at all and quite possibly all you will ever need. But you have to have corners. I've read that some people build extra walls just to provide corners for their K-horns.

Amen, Herman! Hey, I'm not poking a stick at digital xovers. I'm just hoping to impress on the uninitiated that there are several ways to go. Yes, everything is a compromise. No argument there.

Another compromise that can be found is that with bass horns. It is possible to get low enough with a folded bass horn. The Edgarhorn Seismics that I use are such a design and they are about the size of a refrigerator. These get down in the low 20s and can be EQ'd lower.

I'll chime in on the digital crossover question. My basshorns are 16 feet in a 28 foot room. It would be theoretically possible to physically time align if I sat against the far wall but for the sake of space I use Pure Vinyl running on a Mac Mini with an RME Fireface 400 which allows me to have digital time delay. It digitizes at 24 bit 192 Khz and does its calculations at 64 bits. By eliminating an analog RIAA and doing it digitally I avoid the phase shifts at the knees that analog RIAA networks must have. All in all I think it is an excellent compromise and sounds truly wonderful.

Wouldn't it be nice if we could all stop by for a listen to each others systems?

.

.

:The irony may lie in you insisting that horns are not for you over and over and over again."

Actually I have indicated that I am interested in horns and have researched them a good bit though I would surely not claim to be an expert.

I do not know if they are for me yet or not because I have never tried them.

And, its good that both the pros and cons are being discussed because like most anything it is a mixed bag.

Not for the faint of heart though I am fairly certain.

Don't Klipschorns achieve a fairly full range sound in a reasonable size (for horns) package?

My thought is that were I to test the waters with horns, that I would start with a proven design that has been around for a while like the Klipschorn. Its been a long time since I heard these, but I recall these to be one of the things that got me interested in audio years ago when I heard them.

You've been told repeatedly in this thread that true bass horns are unwieldy and that most of us have some sort of hybrid with bass reflex cabinet and midrange horn. The irony may lie in you insisting that horns are not for you over and over and over again. We got it and that's fine.
If more people take an interest in horns, better and cheaper horn systems will appear eventually. In a thread like this, we can become aware of each other and you can become aware of us. Perhaps this is the start of something that could benefit all of us in time. However, unless we start talking nothing will happen.

"Do you admire his system or not?"

Yes.

I just think it it a bit ironic to ask the question "why not horns" and then assert that a 35 foot throat is needed for full range bass. It may well be true but that fact does not support an argument that people should go the horn route.

Also I applaud those who strive to do anything right, but frankly this thread is scaring me further away from horns personally than when I started. Sorry.

Dan - I can hardly fault you for being an analogue purist but please keep in mind that everything in audio demands compromise. To my way of thinking the benefits and convenience introduced by digital processing outweigh the theoretical advantages held in place by analog austerity. Two equally valid approaches. Everybody is happy; nobody is wrong.
Mapman- Your cynical asides are not helping me any. Do they enhance your situation in some way? Do you suppose 32 foot organ pipes are used where a 3 footer would do just as well? Yes, bass horns must be that long if the frequency you strive to reproduce is low enough to require that length. Sometimes this is accomplished by folding the horn. Whatever you are using is a poor substitute for horn bass because you don't know the difference or because you can't accommodate the real deal. I don't have the room or the budget either. The photo link you provided is an example of someone who has the knowledge, dedication and wherewithal to do it right. Do you admire his system or not?

"the throat may need to be like 35 feet long"

I can see the converts lining up now.....

Ah, there is another interesting issue with horns. The question of whether or not to do digital xovers. Digital xovers do make it possible to time align even when the horns themselves are not. However, I am on of those who prefers vinyl source to CD. Naturally I am against ANY digital device in the chain so I chose not to use a digital crossover.

Instead I have the voice coils of the drivers, except the bass horns, physically aligned. (There is a bit more to it, but that is basically how they stack.) So I have a little more work to do with regards to reflections off of the other horns, but there is no digital xover I have found that sounds like I want.

I was hoping to solicit input from people who know and understand the parameters of horn design. Since we aren't hearing from them, I'll stick my neck out and mention a few things I think I know about the subject. If nothing else maybe we'll learn from the people who correct me.
Horns work for speaker drivers just as a megaphone works for Al Jolson or a cheerleader. It was used as a mechanical microphone, amplifier and speaker before we had electronic ones. I believe the idea is one of focus. The energy generated by your lungs or your driver is channeled through a narrow opening and allowed to disburse gradually, just like reducing the diameter of a water pipe increases the pressure.
The lower the frequency being reproduced, the longer the wavelength and the bigger the horn required. This is why bass horns need to be large. I don't know exact numbers but the mouth has be enormous and the throat may need to be like 35 feet long.
Because the mid and lower horns need to large, you need to be some distance back from them so that their presentation can blend sufficiently before the combined wavefront reaches you.
The aforementioned mechanical amplification also explains why horns are so efficient.
Some reasons why horns you have heard in the past were not very pleasant could be poor design, lousy amplification, too damn loud, poor driver integration, cabinet or horn resonance and placement. On this last point, I should stress that, while placement in a high end sound system isn't terribly critical, having the speakers fire at you from similar distances and the same direction could prove very important but be ignored completely by the company who was merely installing "reinforcement". Another matter to reflect upon is the source employed when you heard the horns. It could well have been an 8-track or a beat up record played with a broken stylus. In general horns have been misused far more often than they have been optimally installed.
Metal horns often ring. Many Klipsch owners have taken steps to deaden their horn bodies. Passive crossovers in horn designs of the past were quite rudimentary and cheaply executed. Woofer cabinets in hybrid horn systems have sometimes been constructed of broad pieces of plywood with little or no bracing and no dampening.

My horns are made of 12 one inch thick cherry wood petals. They are conical in shape, meaning the flare is perfectly straight with no elliptical contours. The throat is made of cast aluminum. No ringing, no resonance. I used a pair of JBL L-200 cabinets for my bottom end and mounted the horns with a simple pair of rudimentary brackets bolted to the back of the woofer cabinet. I completely bypassed the native horn and passive crossover and hardwired my amps to their assigned drivers. Then I bought a dbx Drive Rack PA to serve as active crossover, EQ, time delay and level matcher. Because of the extreme efficiency I am able to use excellent sounding low power amps for small money ($300 each) to drive this system and I must say that it will make you swallow your gum. Total outlay 18 months ago was under $5K for everything from the DBX to your ears. The preamp admittedly wasn't cheap. It's a Parasound JC-2.

So I hope this offers some clarification about product, price, placement, performance and pleasure.

Comments? Questions?

Mapman, that system looks impressive but that big white "bass horn" with the big driver is not a true bass horn. My bass horn is 16 feet long and gets down below 40 Hz. That is simply a woofer with a flared opening.

Jhonk, I realize how physically large your woofer cabinet is but I am one of those who would not call it a horn. You are correct though that there is no need to debate that. It's yours, you can call it whatever you wish. You are also correct that to go down to 15 Hz a basshorn like mine would have to be much, much longer so if you want to go that low you have made what I would call a good compromise. Getting down close to 30 is low enough for me so I don't have bass envy.

.

As Herman pointed out back loaded horns really are not horns at all. But this has been debated to death in other forums so most agree that a BLH design is a horn. Most as is mine is a combo or large ported cabinet firing into flared TL. Thus able to produce far lower frequency than equal size front horn. To reproduce 15hz a front horn needs to be near the size I mentioned. Most horns for monitoring or closer seating are hybrid designs horn tweeters horn mid standard woofers. I use a massive horn system in my office. I took much care with driver, horn integration, time alignments thus I can sit about 6ft from such. Hard to answer your questions for I'm not a technical writer just a designer. Some can do both not me sorry. I'm lucky I can write at all not my strong point. I does bother me a wee bit that so many in this thread say what I do and listen too can not be done but hey I know it can maybe thats all I need. I think herman was thinking my rigs a bit smaller than it is.

Great questions. John and Ralph are way ahead of me with horns but I think we are now getting to the reason why more horn systems are not found. Horns do some things similar to boxes but they also many things differently than boxes. There is simply a lot to learn about how horns work when one attempts to setup a horn system. This is especially true when one is doing a multi-driver system. The size of the mouth opening, the size of the horn opening, the flare rate, etc, all impact the freq. response and sound. And we should be considering whether the horn uses a full range driver, or if the horn is front or back loaded.

I listen rougly 11' from my horns. Ralph hit all of the reasons why we hornies like what we like about horns. It is NOT about volume as so many of the uninitiated think. I rarely listen about 90dB even with rock. I don't need to because I can hear very far into the background which I believe is indicative of a very low system noise floor.

And I chose to build a horn system long before I figured out what amps I would use. In the end, I am triamping. One 50+ watt/ch, PP amp for the mid-bass bins, another 50 watt PP amp for the mid and tweeter, and the bass horns are powered by a pro-audio SS amp. This is all controlled by a Marchand active xover.

So you can see that it can go from very simple to very complicated when we talk horns. Most peoples' eyes, especially those here at A'gon, start to glaze over very quickly. :-)