horn loudspeakers, are there any disadvantages?

I'm not sure if my speakers qualify as horn speakers, but I do have a set of Norh 7.0 speakers in Monkeypod wood. Go to www.norh.com if you wish to see their current lineup - the Norh 7.0 speakers are available nowadays in synthetic marble or real marble - wood cabinets were discontinued a few years ago. I was fortunate enough to acquire mine for a very reasonable price, and they sound great, too.

 

I would love to hear the LaScalas or Klipschorns one of these days, though it is not clear if I have the space to accommodate them until that second home becomes a reality. In my current 18x15 living room, speakers with large footprints just will not work. Paul klipsch discovered the magic of horns some 50 years ago. The Germans are only re-discovering the same magic, never mind that they gave the world JS Bach and Beethoven...

 

Have you heard a pair of Cornwalls before Stuart? Smaller footprint and next to the Klipschorns they have the best bass that Klipsch has to offer.

 

If you have a large room, these would be fun to give a listen to.

http://cgi.ebay.com/MEGA-RARE-Altec...725358306QQcategoryZ50597QQrdZ1QQcmdZViewItem

 

revealing of heavily coloured upstream components maybe.

Despite the big-picture simplicity of horns, there remains very few that get all the little details right. Some are better than others, and it is no easy task to discover which ones do the least wrong. I've looked inside a few nice compression drivers, and saw evidence of the manufacturer learning how to do it better.

And then there is the horn itself. Do you want maximum horn loading, or best sonics, or some directivity performance?

Add all this to the physical requirements, and they're bound to turn out like any other loudspeaker...varied! It is no more realistic to lump all cone speakers into a single group than it is to lump all horns into a group.
cheers,
Douglas

 

Well I would not necessarily agree with this. I do almost all my listening on my main system at the same volume level and it is always critical from the sweet spot. I've often listened for many hours at a time. In fact, working in a studio one may listen for many many hours at a time. Granted, one should watch volume levels to avoid listener fatigue.

I tend to agree with your second point though. I don't know that horn speakers by definition are more fatiguing than other speakers, but it depends on the type of horn, on or off axis listening, and many other factors. As I mentioned earlier, some of the most impressive listening revelations for me were when listening to JBL 4320's.

 

Greg, I have heard the modern line of Klipsch speakers but have never had the chance to listen to any of the klipsch models in the Legacy line. Based on some old brochure I got almost 20 years ago, most speakers in the Klipsch Legacy line are very efficient that you do not need more than 10 watts to drive them. I notice we both own CJ gears, though my CJ amp is SS, which I use a Sonic Frontiers Line 1 tube preamp to drive. I am also considering the relatively new Rogue Titan series tube amp. But my primary system will always have a SS amp. I kind of believe a SS amp plus a tube preamp can give you most of the benefits of a tube amp but without the soggy bass.

 

Well I can't argue with that. Though I will say that some tube amps, especially modern day models like my Rogue, are faster (more like solid state) than some older tubed amps. If I'm not mistaken your Conrad Johnson amp is designed to not sound so much like a SS amp but have a bit of that tube magic. I wanted one of those CJ's for years and still may get one someday down the road.

As far as power goes, you're right again. It doesn't take much. I've got my Rogue in triode mode pushing 35 per side. With my volume at ten o'clock it'll fill my room with 100 decimals of music.

And BTW, it's the Klipsch Heritage Line you speak of

 

I'll take two of each please.


Clockwise from Top Left: 4312A, 4333B, 4320 & 4343

 

Greg, Thanks for the correction. By the way, if I remember correctly, I was not overly impressed with the sound of the modern line of Klipsch speakers. It does not appear they can distinctively set themselves apart from other speakers like the Heritage line of speakers can. The CJ SS amps do have a touch of tube sound, even in my Sonographe SA-400, the less expensive line that has been discontinued. Some would argue a powered subwoofer will cure the soggy bass problem inherent in most tube amps. Unfortunately, this would have defeated the purpose of having a tube amp since the amp that goes with that active subwoofer is almost always SS.

 

These speakers on eBay auction look almost like small picnic tables.

 

The Altecs? I'd love to hear those behemoths.

 

I'm sure the mention of this company's name will elicit some giggles from a few here, but Cerwin-Vega has been selling a series of speakers the past year with a high frequency horn coupled to a soft-dome tweeter* (supposedly supplied by Vifa):

CLS Series (click on home audio)

I always wondered if so many horns sounded overly-bright/analytical because they used materials like titanium, aluminum or phenolic plastic(?) for their diaphrams instead of softer ones like these Cerwins. Does anyone know if there is a technical reason for that?

I've always wanted to hear these non-traditional CVs but no one sells them around here (J&R does but for me the shipping for the 12" model is a weeeeee bit high from New York!).

BTW: It looks like these models are the result of a new team in their engineering department (the following is taken from Klipsch's forum). About 3 years ago I read on another audio forum that CV was nearing bankruptsy, then The Stanton Group bought them:

* these slightly redesigned models (the grill now covers the midrange too) include a new tweeter with a copper shorting ring - this helps to make the magnetic field around the voice coil more symmetrical, in turn driving the tweeter dome in a more uniform manner

 

Been using Cornwalls with a Fisher X1000 tube intergrated amp, couldn't be happier with the sound especialy with LP's

 

I don't know about offering a technical answer for you, but the reason that phenolic diaphragms became so popular in the early days is for durability. That plastic/composite material was far more durable than a treated cloth or paper diaphragm methods available in those days. Phenolic diaphragm construction is actually an impregnated cloth, but the methods of construction have improved dramatically since the early days. I own a pair of phenolic mid range compression drivers with alnico magnets that are fabulously smooth.

Aluminum was used for increased power handling and added high frequency extension, after new methods of drawing the material were developed. Being lighter, Al also offers more efficiency. Several top companies had Al domes bonded to Al coil formers, until Altec developed a one piece Al dome/coil procedure for even more increases in power handling, high frequency extension and smoother response over two piece designs.

The same reasons pushed the titanium domes to the forefront, mainly durability and flexibility with the addition of Be to the alloy in some cases, but smooth, even frequency response took a hit and the Ti diaphragms have a rising response to contend with, but being lighter have some extension to the top end and efficiency is increased. That rise in response at the frequencies coinciding with greatest human hearing sensitivity fools many people into believing they are more detailed. It is simply a response peak at 3 to 5 KHz range that causes the problems. The uneven midrange response makes the Ti/Be diaphragms a deal breaker in my opinion ... I would rather use a one piece Al and supplement the ultra highs with a different driver. Another disadvantage of Ti is the way it burns when overheated and in the event of failure from overpowering the magnetic gap is almost impossibly crusted with ash, making it difficult to save.

The smoothest horns I have seen have a phenolic (which I have read is ~6 times harder than in the 1940s) mid range driver, aluminum one piece high frequency driver. I would like to hear the cloth dome CVs. I would expect an even smoother response from treated cloth and possibly more extenson into the highest range, if they can keep them together under pressure. Maybe someone who has the Cerwin Vega drivers can comment further.

 

Break-up mode

There is a big difference between horn loading a conventional dome tweeter and a true UHF compression driver. It is the break-up modes inherent in the different diaphragm materials that give each one its sonic signature/sound quality, with all else being equal. The break-up mode is when a diaphragm is deformed and is no longer acting like a piston. If you could take a super high shutter speed picture of the diaphragm while it was producing sound, you would see it's dome deforming and causing distortion, with peaks at certain frequency points. You want a diaphragm's break-up mode to be as high as possible, ideally higher than it's intended prime operating frequency range. Titanium, while very light and stiff, has break-up modes as low as 4-6khz, even though it has useable FR well beyong that point. Aluminum is better at 7-8khz and Beryllium is about 14-15khz. Some companies have resorted to coating the diaphragms with a dampening material that calms this unwanted effect greatly, the JBL 2451SL and 435 Be. are prime examples. I'm not sure, but I think that the phenolic diaphragms have better/higher break-up modes than their Ti. counterparts and also are not normally used in a HiFi application much higher than 5-6khz anyways.

 

I had '79 Cornwalls and '88 La Scala's and currently own '80 Khorns. The CW is a more well-balanced speaker than the Las because of the BASS factor. The Las have a very LEAN BASS at around 50Hz or so. The midrange on the Las is much better than the mid of the CW though. I think the Las use the same midrange driver/horn as the Khorn? I got rid of the CW's because the midrange horn was somewhat harsh and fatiguing for me (I ran them with Yamaha SS, MC30's and Marantz 8b). I REALLY liked the Las...they were very exciting/dynamic speakers. But, the lean BASS just didn't cut it after a while for me. I ended up locating a pair of Khorns for a reasonable price and now have the best of both worlds... Better BASS than the CW's with the fantastic mids of the Las. If I had to choose between the Las and CW's, I would proabaly go with the Las with a sub just because of that fantastic mid it has. The CW is a great speaker in it's own right though... Probably splitting hairs here.

 

Flatlander/Ethos: thanks for all that info. IIRC horns are an acoustic transformer, where near the diaphragm the speed of the air is high (relatively speaking) but the pressure of it is low; but as the sound wave exits the horn mouth the pressure is higher now. I was thinking maybe that soft materials like a cloth dome would deform too much in that type of environment. Or maybe until now it has just been "accepted practice" to use very stiff materials?

Not to derail this thread too much, but does anybody know if an acoustic lens like many JBLs use qualifies as a type of horn? What are their advantages over a horn?

 

Horns

JBL used an acoustic lens to control dispersion with many of it's Legacy horns. They are used in combination with a horn, but are not horns themselves. Materials used in dome tweeters and other direct radiator transducers do not suffer from the same effects as their compression driver counterparts as far as I'm aware of, at least not to the same extent. I have found good quality silk dome direct radiators to sound quite smooth, BTW.

 

Good post Charles. I agree with everything you say here. I don't have the corners for Khorns (or so I'm told) so I'm enjoying my LaScalas with what bass they will give. There are some mods I've been studying on though that look pretty promising. A couple of subs are in the back of my mind also.

Again, good post .

 

As a young single man in my 20's in the late '70s, working at a music store, I managed to own 2 pair of Khorns, which I placed in my corners, one inverted on top of the other. Imagine a large MTM arrangement using KHorns, I had a very big, musical sound in a fairly large room that required almost nothing from my 60 Watt Mac to really hit you hard. Yet the tone was totally believable and you could never find the speakers, if you didn't know what that stuff in the corners was about. All I knew about room treatments was that you needed to "deaden" everything, so I had way too many velvet paintings everywhere. I was fortunate enough to have an open floor plan with large archways to break up directivity of reflected sounds, so I "had it all" and didn't even know it.

About that time in my life I experienced BIG sub 30 Hz bass for the first time and I was no longer interested in the K-Horns. Since the Ks had been in production 'forever' at the time I wanted new stuff that had a complete full range sound and I let the best sound I ever had get away, while I became a bass head for a while, and bought one of the MC2500s that I still own.

The K-Horns are killer speakers if you have the corners! Add to them some SUBstantial bass and you will approach nirvana, if you can integrate them properly.

Getting back to the thread topic - I must add that the only disadvantage I have experienced using horns is that to get really low bass out of them, you need to use very large horns and corner loading if possible. Otherwise, the truncated mouth designs like the horns used for PA systems usually exhibit a peaked response in the low ranges. Stacking them up in multiples will increase the effective mouth area and go a long way towards smooth low frequency response, but you would need a fork lift to stack them.

 

You've got some of the theory correct, but some of it backwards.

A horn is indeed an acoustic transformer. The most inefficient transfer of energy in our systems occurs at the point where the vibrating diaphragm meets the air. A horn is capable of adapting a small high pressure area into a larger lower pressure area. By doing so, horns increase efficiency of a system by as much as 10dB (and in some cases, more) compared to direct radiators of a size similar to the compression area.

So, near the diaphragm and throat of the horn, the pressure is extremely high in some horn designs and near the mouth, pressure has decreased, but the horn shape has widely dispersed the wave, exciting more air than possible without the horn. Hope that makes sense.

One other item that hasn't been discussed is what has become known as a phase plug or phasing disk. If you have a diaphragm in the shape of a dome 4" in diameter and you are pressurizing a horn throat that is 2" in diameter, there needs to be a way to capture the waveform and get it into the horn as efficiently as possible. The problem is that sound from the edges of the diaphragm travels a different distance compared to the center area.

A good phase plug will allow the sound pressure from center to be slightly delayed, while the sound pressure from the sides catches up and all the pressure enters the throat as a coherent, in phase wave. Another advantage to a well designed phase plug is that the pressures across the surface area of the moving diaphragm are equalized, which will help to control break-up modes and also increase the maximum power handling. A stiffer material becomes less of a concern if the pressure can be maintained at all points on the surface of the diaphragm. The phase plug is built into high frequency compression drivers, in most cases, and also makes a huge difference in the sound of the horns, by helping to smooth out frequency response ripples.

Sorry, this post has gotten so windy.

 

Visual aid

Great info Flatlander!. Here is a good visual example of the mass break up problem. The top is Beryllium and the bottom is Titanium. This is at 14.5khz

 

Thanks Greg, I miss my La Scala's... Man they sounded nice and looked purty too. Mine were DARK Walnut Laquered Birch. Beautiful sound with beautiful wood grain... If I only had the room for all...

As for subs w/La Scala's... make sure you do your research to find out which subs will be FAST enough to integrate nicely with the FAST sound of the La Scala's. Check with the Klipsch forum before purchasing anything.

 

Yes Charles, matching the subs to the LaScalas is critical from what I've read. Speed is the issue. Placement is an issue for me as well. If it's not one thing it's another. Oh what a great hobby .