This post is to explore why the KS12024 horn stands out as one of the best sounding of all small horns.
What is different from other horns? How do these differences influence its sound and can we understand them? It is important to remember that if we observe a difference and cannot explain it this lack of explanation does not mean there is no difference. It only means we have not yet been able to catalogue and attribute it but still the difference remains. Some electrical engineers have disagreed with this and argued that if it cannot be measured and explained then it does not exist. This is a banal error (so lacking in originality as to be obvious and boring) and can cripple eventual understanding. Science is a tool, and a very useful one, but if you let it run the show it will do so like a tool. In aviation to call someone a tool is an insult. It means they follow the book and cannot think for themselves – great for day to day activity but worse than useless during critical events. Music is a constant series of critical events. I had a nugget (student) once who held a PhD and he literally could not break procedure to save his life. Sometimes its just you and the big blue… (actually it always is) When science can make a Stradivarius we can speak of this again.
Let us begin with the observation – the KS12024 horn sound. I shall use other observations than my own – a conversation: from a Japanese publication:
Atarashi: The first listening of the Ks12024 horn is pretty good and very impressive. Colourful expression but very soft and right tone.
Shinoda: Good compatibility with the WE555 – very balanced.Doi: KS12024 horn is the core of Westrex sound systems.
Atarashi: You understand when you hear ‘’Casal’’ with such a good quality. The fact to clearly hear both the sound of the ringing and the sound of the string body, both being organically overlapped, gives the firm presence impression of the cello. Emotion is well transmitted, as if to express the music with the help of like Casals Bach. It is an emotionally rich sound.
Shinoda: I am not focusing on scratches on the SP record; I can concentrate myself on music. I feel a sense of depth and it sounds quite well.
Doi: More noteworthy, it is no fun listening to music. No likes and dislikes of music genres.
Atarashi: Yes. “Casal” as well as “Sonny Rollins” or “Kay Starr”, all are lively and enjoyable performances.
Shinoda: I think this system tends to give a HiFi tone, I’ve felt the energy impression and the thickness of the sound together. For example, “Sonny Rollins” in front of the stage, plays saxophone lively first, joined by strong sidemen from behind with Max Roach, you can hear the music even more impressive. That’s because there is a bodily sensation, you can feel the thickness part of the sound, performance is close to the human perception without being disordered.
Doi: There is an energy impression in sound, at the same time also the tone is beautiful. However, it is wide range, as if it was a full range system. This is a very valuable horn, which gives the best quality of the WE555 driver, according to me.
Atarashi: When you heard the sound of this combination, you think that extension of WE555 is not difficult to obtain (laughs!).
Shinoda: I agree. The WE555 is splendid, and this sound is difficult to obtain with many horns.
There it is – on the ground, laying in the grass, a perfectly good gauntlet.
On initial examination the horn incorporates:
1) Simultaneous and varying exponential and conical expansions.
They look like this at their beginning.
3) A 45° bend 90mm from throat origin where the conical opening angle increases from 30° to 50°.
This poses the question of a possible correlation of the bend and increase of conical opening angle.
4) Throat size is WECO standard 0.7″ or about 18mm
5) Cast aluminium has roughed surface perhaps performing boundary layer excitation (BLE) – the intentional creation of small modes which prevent larger ones from developing. Earlier in wooden horn building I was surprised that the horns sounded better before they were sanded and finished. The better they looked the worse they sounded. This is perhaps why. Of course we stopped finishing them…
A simular texture is used in reproduction for this reason.
6) Exponential expansion begins after 180mm from throat origin alongside the conical which continues and determine the output pattern. The conical propagates in the lateral expansion – the exponential the top and bottom. You might want to call this a radial horn however it is purely conical for the first 70mm and then a hybrid of some kind.
In conclusion the expansion is 30° conical for 70mm then at 90mm this is divided into asymmetric exponential cells which increase in to a 50° conical total for another 90mm where this 50° total then combines with another exponential top and bottom (going into radial) further increasing the expansion accordingly. It is a thus compound horn: conical, conical/multi cell exponetial, then radial multi cell.
Further interior examination shows there are two separate countours of the four cells at the beggining.
These are grouped as the two internal cells being equal and the two external cells being equal but the internal and externals are slightly different to each other. Moreover these individual expansions appear to be somewhat exponential.
They are different even if we consider the spherical wave expansion as can be seen in another x-ray view.
This is probably enough to get us started as there is enough here to separate the 12024 horn from the other horns we may know. One can only wonder how this horn was developed.
Material also makes a difference – as sound inevitably travels through it increasing in speed and altering its character. These leave the horn ahead of the sound waves traveling only in the air. The original aluminium has a ringing character or glare when compared to plastic, wood or bronze as can be expected. Plastic is already better than the aluminium in reducing this slight glare which is only noticeable when directly comparing the two materials side by side. AL was probably selected for it’s ruggedness in a commercial environment rather than for epicurean reasons. Bronze takes on an even quieter, clearer and more present aspect. It also lends a sweetness or naturalness something like nickel cores do in transformers. Wood has its own and lighter form of natural sound. Combining these works very well.
In the another post I will talk about different drivers and compare the LM555, TAD 2001 as well as a drivers with phenolic diaphragm. Watch for the dark horse.