Well, you can look at it this way - if he inherits the speakers from his dad, his dad probably also had a good tube amplifier to go with them! Just tell him not to mess with those new fangled solid state thingamajigs

PS: I didn't get my 106db/w speakers from my dad, nor his Jackie Gleason LPs

[This message has been edited by soundhound (edited January 26, 2003).]

Dear SoundHound:

Your post was exactly on point. Actually, I have been following this topic forum with great interest, but I thought (with a little nudge) you could make a more clear case for the existence of tube amps so that us deputy's could get a handle on it. You did a great job.

There are many who believe that solid state amps are the logical choice for all. Most of my clients are of the misconception that 'solid state amplification' means digital signal throughout, and that 'tube amplification' equals more coloration and distortion. Some seem to have suggested these falsehoods in this thread as well.

As I believe you stated, the crossover distortion of a typical solid state amplifier at very low power levels is a dynamic condition that is not compatible with your speakers. A speaker with 106dB sensitivity will benefit from the design/performance characteristics of your tube amps. It is quite simply... amazing how small the power requirement is for moderate levels of volume (signal level) in your situation.

It seems to me that it must be a labor of love for you to make your speakers work as well as they do. This level of passion and expertise serves you well. For the rest of us who will never jump in the deep end of the pool; less sensitive speakers, and more powerful solid state amps like those made by Outlaw are probably the logical choice.

Thank you for your kind response.

Allan

I think yhis has been a great post and I think many (myself included) have been somewhat educated. I've been wondering while reading, is there a benefit to either high or low sensitivity speaker designs. What I was wondering (especially from soundhound) if today you went to purchase speakers and you had all of you technical knowledge but had never listened to any speakers what would be your criteria for evaluating speakers. I guess what I'm asking is do you love your tubes because you love the sound of the horn speakers and that is the best thing to drive them? Or do you like the sound of the tube amp and you need those horns to make the package work at it's best. Or do you just enjoy having a setup that you can tinker with? My guess is you've spent a fair amount of time getting your system to the point it's at now and I'm just curious of the road you traveled getting here.
I would also request opinions on sensitivity vs sound quality. Is there any correlation of the two or does a speaker just end up at a certain sensitivity based on it's design?

I've listened to high, mid and low efficiency systems that sounded great. Horns are waveguides, so they have unique sonic properties. Whether you like them or they work well in your room is a personal choice - listen (to good ones) and see. Horns are complex and easy to do badly, moreso than some other sorts of designs, so QoI is a great concern with them.

Also, in bass systems efficiency = size, (generally) so that is something to think about.

Horns used to be the only way to get any sound out of the feeble power amplifiers available in the 1920's. They were used in large spaces like movie theaters to make a few watts of power fill an auditorium. And, of course, they were used on acoustic phonographs to get any sound at all!

Is there an advantage in using them now? Well, let's see.

They are still used in movie theaters, stadiums, concert halls and any other place where the sound has to be very loud, and fill a large space. One of their chief advantages is that because of their sensitivity and efficiency, they can easily take the wide dynamic range of motion picture soundtracks, live music, etc. If you tried to push any all-direct radiator speaker to the sound presure levels encountered in filling a movie theater, it would self-distruct in no time. Also, horns can be made to any directional characteristic needed. They can be made to fill a very specific area of an auditorium, with no sound wasted from being directed where it's not needed.

None of the above advantages have anything per se to do with home theater, or sound quality in general. In fact, the above systems sound pretty darn bad by hi-fidelity standards!

Now, Paul Klipsch of Klipsch Loudspeaker fame recognized the advantages of horns for home use in the late 1940's and created the Klipschorn. He championed one unique advantage to horns that does have a direct bearing on sound quality. That is low amounts of doppler and harmonic distortion. Simply put, doppler distortion arises whenever the source of sound moves, relative to a fixed point (the listener in this instance). What is moving? Picture the cone of a 15" speaker moving back and forth by 1/2" as it reproduces a 30Hz tone at a loud volume. Now superimpose another tone of 1000Hz on top of that 30Hz tone. The speaker cone is now moving that 1000Hz tone nearer and farther from you at a rate of 30Hz! The effect is exactly as that of a car passing you by while honking it's horn. In that speaker, it will make the 1000Hz tone sound like it's 'underwater', or 'gurgly'. You are literally frequency modulating that 1000Hz tone, and creating distortion sidebands in the process.

Paul Klipsch reasoned that since a horn is very efficient, it's moving parts (the diaphram of the horn) needed to move very small distances in order to create healthy sound pressure levels. Because of this, his horn speakers produced dramatically reduced levels of doppler distortion (and also lower levels of harmonic distortion, for the same reason). They sounded cleaner than what was available at the time.

This is still true today, and is one of the chief advantages of horn speakers.

Of course, speaker technology has marched forward since that time, and today's speakers are much better than they were in 1950. BUT - take any speaker system today with direct radiators and play a loud continous bass tone that the speaker can reproduce, and add another pure tone that will be reproduced by that same driver (that has not been crossed over to the mid-range speaker by the crossover network), and you will hear doppler distortion if the level is increased enough.

Does this still matter today? People who make horn speakers (like Klipsch) think so.

When hi-fidelity meant only two speakers and music only, all this was somewhat a non issue to all but a few crazies like myself. Now, with the advent of home theater, with it's requirement to reproduce all manner of explosions, gunfire and other acts of violence, maybe it does matter. There's no denying that horns reproduce movie soundtracks with more 'punch' than direct radiators do. Those of you who have Klipsch speakers probably purchased them because they sounded good with movies. But does this make horns better?

That is a personal question. Any good speaker can sound wonderful. Speaker manufacturing technology has evolved tremendously, and today's consumer speakers sound WAY better than they did 20 years ago. But here are a couple points:

As discussed above, horns reduce forms of distortion like doppler, and also harmonic and intermodulation distortion because the moving parts have to move so little to create high sound pressure levels.

Because horns can have a very well defined directional pattern, they are very adaptable to the principles espoused by certification entities like THX. It is much harder to control directivity with direct radiators. The sound can be controlled and kept off walls, floors and ceilings to a greater extent before it reaches the listener. This has become important in home theater.

With a all-horn system (like mine) it is possible, by nature of the length of a horn, to achieve precise time alignment between the low and high frequency drivers by simply moving them in relation to each other, forward and back. Moving their relative position while looking at the reproduction of a square wave is a good way to achieve precise time alignment. This is not possible with direct radiator speakers, when the drivers are all mounted on one flat baffle. This limitation can be overcome however by slanting the baffle, or having stepped mounting surfaces for each driver.

Then, there is the characteristic 'horn sound'. This can be absolutely wonderful and 'alive' sounding if the horn system is executed well. Horns can also have a unique way of imaging the soundstage. They can image well behind the speakers (in stereo) as most conventional designs can, but they also have the ability to image the performers well into the room and all around you, way beyond the confines of the speakers. I've yet to hear a non-horn system that can do that as effectively.

Horns are unfortunately not executed well a good deal of the time, and the resulting horns sound simply "honky". Horn systems such as these, and horns used for PA applications have given them a bad reputation for some people.

And, as I have outlined in my previous posts, as horn coverage of the audio spectrum is widened, it becomes increasingly important to use tube amplification. This is because of the uniquely wide "class 'A' window" these amplifiers afford.

Horns are used mainly for tweeters in consumer systems today. It is very expensive to make a horn. In fact, most all horns today do not make use of a very important component that complements the horn: THE COMPRESSION DRIVER. Most horns today could be more accurately described as horn-loaded tweeters. They use a conventional speaker driver with a horn in front of it. A compression driver has a diaphram that fires through a 'donut' shaped magnetic structure. But before it reaches the throat of the driver, the sound passes through a 'phasing plug' which corrects the phase of the signals that enter the throat from the various parts of the diaphram. Thus there is no phase cancellation from say , the sound coming from the edge of the diaphram and that coming from the center. The problem with compression drivers is that they are extremely expensive to make. They require machining of precision parts, and this makes them cost prohibitive for consumer use.

The makers of today's horn speakers have done an excellent job of working around some problems arising from the lack of a true compression driver. Some of the phase problems resulting from direct loading of a conventional driver remain, however.

As home theater has come into being, there has been a gradual shift upwards in the sensitivity of speakers. This is probably for two reasons. More sensitive speakers (especially horns) are more able to take the abuse of sound effects that exist in modern motion picture soundtracks. This is simply because the speaker elements do not have to move as much to generate a particular sound pressure level. Thus less likelyhood of damage to the drivers. Another reason is that higher sensitivity speakers makes it possible to lower the power requirements of the power amps that power them. This was not much of an issue when amplifiers only had two channels, but gets to be a very big issue when as much as seven channels are put into a single amplifier chassis. 7 times 1000 watts? Get 'outta town!!

Would I purchase horns now, knowing what I do? You bet!

Should YOU? Well, that is a question only you can answer. Shop around and give the various horn designs a listen. There are only a couple firms that market all horn speaker systems currently, most systems having horn tweeters. Therefore, for better or worse, your selection, and therefore how crazy you can get with it, is somewhat limited. That is, unless you go with professional speakers....

[This message has been edited by soundhound (edited January 27, 2003).]

Keta:

My affair with tubes started when I was about 10 years old. I had a phonograph (one of those cheap things kids have). I used to play records on it all the time, and when the needle wore down, I just stacked pennies on the tone arm till the needle stayed in the groove. Then one Christmas my parents gave me a 'nicer' phonograph. I played it, but I still preferred the sound of my old phonograph. The new one just didn't sound 'right' to me.

A few years later I discovered why. The older phonograph had a vacuum tube amplifier, and the new phonograph had a solid state one!

As I grew older, I had a lot of amplifiers, tube and solid state. I always preferred the sound of the tube amps. They sounded more 'like music' to me.

I attended college, majoring in electronic engineering. After bumping around for awhile (never leave a 22 year old kid to his own devices) I started working for Altec Lansing, while they were still headquartered in California. There, I was exposed to the whole spectrum of sound equipment, from speakers to electronics, and such esoteric things as transformers and microphones. I got to see first hand the various technologies involved. My job was to design automated testing equipment for use on the production lines, so I had to learn the engineering principles behind all things audio.

It is here that I was exposed to horn speakers. I actually wound my own diaphrams for use in my horn speakers, and learned all the things that make a good verses bad horn. The horn speakers I bought while I was there I still have, and are now my main left and right front speakers in my home theater setup.

I found my horn speakers worked especially well for home theater because they were literally speakers intended for use in movie theaters! I did a great amount of modification and tweaking to them to tame some of their bad personality traits, and to make the most of their strengths. All these things I learned to do from the engineers at Altec Lansing.

It was about this time I also came to realize the symbiotic relationship of horn speakers and tube amplifiers.

Later, I was introduced to single-ended triode tube amplification. I found that this was an ideal solution for driving high frequency horn speakers because of the pure class "A" nature of their output stage.

So that is the story of my life with tubes and horn loudspeakers

I demoed some Klispch (Tweeter UE model ranges) and decided against them. I find your last couple of posts informative because I’m always looking for the ‘why’ behind why I prefer one thing (or don’t). Wishing to understand the reason particular products, possibly by their design, will have qualities I gravitate towards.
When I had a very short demo period and ended by choosing the Vienna’s much of the material I took with me were CD’s the only DVD I included was ‘Donnie Darko’ which at a certain dB level and in certain portions of the soundtrack is difficult for speakers tending to push them into distortion so I thought it would be a great test. It’s funny you mentioned some choose Klispch for its dynamics for HT. Although this area of capability was very important to me…with the guys here we spend many hours on blockbuster DVD’s. But I prioritized in my purchase that the speakers could handle music in a certain range and in a certain way that the Klispch fell short (for me), and I went with the Vienna’s. I felt the Vienna’s did not do (what they shine at), with busy HT type passages, - the Vienna’s are capable but not jaw-dropping for most HT, (although they have moments) dependent on Soundtrack. . I do not mean to state I feel they are incoherent or thin in detail or any characteristics as negative as that for HT, - but there is some ‘lack’ I sense that I can’t quite put my finger on. Maybe in part the “drivers on flat plane effect” (among other possibilities I’m trying to decipher) that you were detailing. Regardless, - several other speaker choices like the Martin Logans or Klipsch did not ‘move’ me with CD’s. I won’t give up listening to Electrostatics or horns or any other implementation whenever available to hear. But reading posts such as yours help me understand why sometimes I might lean this way or that.

SH and Charlie, this is one portion of why I enjoy the forum, for when those with particular expertise in certain passionate favorite topics let go a little of that info for fun. I’d say in virtual terms it’s the night break, - when the saddles are on the ground we’ve rolled up our interconnects, the moon is full and the cattle are quiet and we are all hanging around the
keeping good company.

Thanks for the share. (and the patience).


[This message has been edited by Smart Little Lena (edited January 27, 2003).]

Lena:

Your choice of speakers does not surprise me, given your emphasis on music reproduction. It is exactly that focus that is the biggest challenge for horn speakers. Of all the tweaking and fiddling I've done, by far the largest effort has been in making the reproduction of music as good as that of movie soundtracks (after all, movies are comprised of music too). It can be done.

I have succeeded in doing this, BUT it has involved a lot of work and sweat!

Would I recommend horns for people whose focus is music reproduction instead of films? NO WAY! Unless one is willing and able to do a lot of work, or finds a horn system that already sounds great to them for music, I would recommend a speaker system with direct radiators.

I would be interested in hearing the feedback of the other Outlaws out there that have horn systems like the Klipsch. How do they think they perform for music, verses movies?

[This message has been edited by soundhound (edited January 27, 2003).]

My personal system is to start at the ear (or eye) and work backwards, that way at least token examination is given to things like distance and room.

YMMV!

Here are a few more things to ponder.

Horns allow a greater mass of air to be coupled to a driver. For instance in the case of a 6" driver the mass of the air that is actually coupled to the driver is typically much less than the mass of the driver. This causes the driver to behave badly. A well done horn provides an 'impedance match' that allows the designer to couple more mass to the driver. There is a school of thought that states this is what a good horn should do.

There are other ways to control this 'behaving badly', but they all have trade-offs.

For instance a bass horn, well done, will be absolutely enormous due to the huge wavelengths involved. Most bass horns are somewhat compromised (undersized, folded, etc.) due to this sheer scale involved, although they often produce decent results.

And to really throw a curve, there are a lot of folks who like a design called a 'back loaded horn' where a horn is used instead of an enclosure to load the rear of a direct radiator (or front horn) system.

http://hornet.hi-fi.hr/HedStart.htm
http://www.vt52.com/diy/diypage/hedlund/hedlund.html
http://melhuish.org/audio/horn.htm