Tractrix vs. exponential

[WMcD]

There is also the notion out there that “conical” horns have fewer modes, or internal reflections.  Subjective reports are that they are less “honky.” 

 

There is an issue of nomenclature when it comes to “tractix.”  In a pure mathematic form it seems to have an area which is exponential or hyperbolic at the small end, and then more like conical as it expands, and then a wider flare at the big end – and the cross-section is round. 

 

Nonetheless, people make mid horn of various shapes which are not purely tractrix.  Roy Delgato describes his initial designs as a “modified” tractrix.  We can’t extract very much information from that except that it is not a pure tractrix.  Saying what it is not doesn’t tell us what it is.  The waters are muddied because Klipsch took out a trademark on “tractrix.” 

 

As far as coverage control, DB Don Keele did a lot of this.  He also credits PWK’s K-5 from decades before.  Some tractrix look like his work.

 

I really like the sound of the “tractrix” on the Forte II, and Quartets (I’ve not heard a Chorus II).  Now there is a Forte III which uses an improvement by Roy where he adds “mumps” in the mid horn.

 

My overall suspicion is that Roy has created a mid horn reducing modes (reflections) and having good directional control.    I dislike subjective reports, even my own, because anyone can say “this or that.”  With modern time domain waterfall plots we may see some objective evidence. 

 

 

[Chris A]

1 hour ago, WMcD said:

Saying what it is not doesn’t tell us what it is.

I would think that's a function of a certain Klipsch employee's wishes. 

 

If you're a horn person (i.e., a horn acoustics engineer), when you look at the modified tractrix, it isn't difficult to see what they're doing.  It's the "what are they trying to achieve" design requirements and the "what are they actually doing" which is where the sensitivity comes in.  The horn design wasn't patented, so anyone can imitate it (i.e., it's been a lot longer than 12 months since their first public disclosure...about 20 years ago). 

 

A description of how the horn profiles are constructed is pretty clear if go back to the original article by Dr. Bruce Edgar in Speaker Builder Magazine, 1981 on the Tractrix horn (see figure 9).   It's not rocket science, but I certainly wouldn't try to belittle the effort it took to come up with the original K-510 and K-402 designs: they're much better horns than one would guess just by looking as the resulting horn profiles. 

 

By the way, the Klipsch modified tractrix profile doesn't have conical section in it, either in area expansion or the curve shape of the horn walls.   If you do your due diligence you will see that very clearly.  But the horn walls are flat for about 2/3s of the horn's length, and I believe that trips up a lot of people to believe that a "flat sidewalls equal conical expansion".  It doesn't and it's important to note that fact.

 

Chris

[Dawson's Ridge]

18 hours ago, Chris A said:

 

If you're a horn person (i.e., a horn acoustics engineer), when you look at the modified tractrix, it isn't difficult to see what they're doing.  It's the "what are they trying to achieve" design requirements and the "what are they actually doing" which is where the sensitivity comes in.  The horn design wasn't patented, so anyone can imitate it (i.e., it's been a lot longer than 12 months since their first public disclosure...about 20 years ago). 

 

Chris

99% of speaker companies and audiophiles are not horn people. Horns have been around for a very long time. Not a mystery how that differ from direct radiators. I am fully aware of the usual reasons given why more people don't like horns but I can't quite come up with the real reasons. ???  

[jjptkd]

Horns can be a big pain in the arse! They are very sensitive to room acoustics, equipment matching, they are very directional and the high sensitivity of most horn systems really brings out the worst (and best) in recordings. I would say it is much easier to get things wrong when setting up a horn based system than a direct radiator designed system. Even when you get things absolutely correct and everything is bliss all it takes is one bad recording to make you question everything, it can be very frustrating at times.

 

 

[derrickdj1]

6 minutes ago, jjptkd said:

Horns can be a big pain in the arse! They are very sensitive to room acoustics, equipment matching, they are very directional and the high sensitivity of most horn systems really brings out the worst (and best) in recordings. I would say it is much easier to get things wrong when setting up a horn based system than a direct radiator designed system. Even when you get things absolutely correct and everything is bliss all it takes is one bad recording to make you question everything, it can be very frustrating at times.

 

 

You are right in that a bit more care is needed for setup.  Now, the part about one bad recording, I have a different perspective.  If your music collection is large enough, then you have a few bad recordings.  These are easily recognized and just aren't played much.  I don't question the whole system or start a hunt for new gear.

[Chris A]

39 minutes ago, Dawson's Ridge said:

I am fully aware of the usual reasons given why more people don't like horns but I can't quite come up with the real reasons. ???  

I have a pretty good one:  horns are much more difficult to do well than direct-radiating loudspeakers.  Almost all of the horn-loaded speakers that I've heard, other than Klipsch and a couple of others, are not worth much in terms of hi-fi reproduction.  Also, since the early 1950s most people have gotten used to seeing loudspeakers that are far too small to do a credible job of hi-fi sound reproduction.

 

Most horn-loaded loudspeakers over the decades since their introduction in the first successful cinema loudspeakers (notably the Shearer horn and the Altec and JBL upgrades/replacements for the Shearer horns) have been not without significant compromises and/or issues regarding their size. Paul Klipsch made his name on his hi-fi and compact (relatively speaking) corner-loaded bass horn design...as compared to an Altec A1 or A2.

 

It's only been more recently that fully horn-loaded loudspeakers of high quality and smaller overall dimensions have come onto the market and have really gotten people's attention.  The Danley multiple-entry horns (Unity, Synergy) come to mind.

 

Chris

[Chris A]

1 hour ago, jjptkd said:

I would say it is much easier to get things wrong when setting up a horn based system than a direct radiator designed system. Even when you get things absolutely correct and everything is bliss all it takes is one bad recording to make you question everything, it can be very frustrating at times.

Very good hi-fi horn-loaded loudspeakers reveal industry-wide issues with typical direct-radiating  manufacturers' loudspeakers, their driving electronics (i.e., too much power is required to realistically reproduce recordings, rendering low-power performance that's quite poor), and the recording industry's complicity in furthering the practices of these types of very poor loudspeakers by making recordings "sound good" on them (although "sound good" doesn't sound anything like the real thing). 

 

One of the reasons why i demaster my recordings is that almost all recordings have the artifacts of mastering exclusively for extremely poor loudspeakers and ear buds.  I've found that it's not only possible to undo much of that damage, it's amazing what you hear once that "fiddling around" is undone...and you get a glimpse of what the recording musicians did--with your ears.

 

But it apparently takes extremely good horn-loaded loudspeakers to plainly hear those differences once they're undone in the recordings. On Jubs set up well with good horn-loaded subs, the differences between commercially released and demastered recordings will simply knock you flat in terms of getting your listening attention.  It's not close: those commercially released recordings all sound like shrill and poor quality table radios.

 

I find it very unwise to blame your loudspeakers for recording issues.

 

Chris

[Dawson's Ridge]

2 hours ago, Chris A said:

 

Most horn-loaded loudspeakers over the decades since their introduction in the first successful cinema loudspeakers (notably the Shearer horn and the Altec and JBL upgrades/replacements for the Shearer horns) have been not without significant compromises and/or issues regarding their size. Paul Klipsch made his name on his hi-fi and compact (relatively speaking) corner-loaded bass horn design...as compared to an Altec A1 or A2.

Chris

I personally believe this, directionally, is the primary reason. Big and boxy horn speakers dominated the market and homes from the 1930's into the early 1960's. Then the Acoustic Research AR-3A and modern transistors came along. Now you could have big sound in a small cabinet. Even though bass reflex speakers were inefficient that was not a problem with the introduction of powerful solid state amplifiers at about the same time. In 1966 Acoustic Research had 1/3 of the US speaker market.

 

Today the audiophile has many choices. Bass reflex continues to be the most popular design for what I believe are the same reasons they became popular in the 60's. You can get big sound from smaller cabinets and the marketplace is full powerful solid state amplifiers. But today I believe there is another reason why bass reflex still rules. Cabinet construction, including materials and design, has progressed significantly and many cabinets are stylish and attractive to the majority of audiophiles. My Palladium speakers were designed by the BMW Design Group and they are an attractive addition to my living room decor. The cabinets are sculptured from 7 layers of different woods with high quality unique veneers, accents, and magnetic grilles.

 

Klipsch just introduced the Forte III. It is big and boxy and made from standard MDF with common veneers and looks just like the I and II. 

 

        

[Chris A]

I've personally found a high percentage of acoustic instrument musicians are drawn to horn-loaded bass reproduction.  Perhaps that's one of the reasons why the Khorn remains in production.  If you haven't heard a pair of well-set-up Jubilees, I recommend it.

 

I've never chosen a bass reflex box in a lineup: I don't prefer their lack of dynamic tightness.  But the Palladium is apparently one of the better implementations that hides that weakness well.  For me, BR gives up too much acoustic performance for a front loudspeaker --L,C,R.  They do fairly well as surrounds, however.

 

YMMV.

 

Chris