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La Scala compaired to Klipschorn


lascala1983
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Are the horns in the Klipschorns and La Scalas the same(for similar years)? I know the boxes are different, however, the horns both say K-55 or K-77. Do the horns have the same dimesions? Are they interchangable? The reason I ask is I've seen a pair of Cornwalls with the same k-55 horns, but they didn't look as large as the La scalas. Also, are the crossovers the same? Last, are the Klipschorn really that much better or is it a matter or preference?

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Klipschorns have better (deeper) bass response than the La Scala

The midrange and tweeter horns are the same (Khorn, La Scala), basically

The midrange and tweeter drivers are the same, basically

The crossovers between the two are slightly different

The drivers on some Cornwalls will work on the La Scala and the Khorns, but the midrange horn on the KHorn and La Scala are much larger than the Cornwall

The K55 you refer to is the driver, not the horn.
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The elevation from the floor of the mid and tweeter I think makes a possible subtle difference, too. The KHorns are a bit higher... Also, the KHorn pretty much has to abide to a 45 degree angle toe-in (unless extraordinary measures are utilised), whereas the La Scalas can be toed in at various angles (mine work well at about 30 degrees from the side walls to extend a little further into my room). The LS can also be angled up a bit or even elevated a little - lots of versitility, most probably being attempts to make them sound more like the superior KHorn...? A lot depends on the room configuration with which you have to work. The general consenus I think is that if you have two good solid corners the KHorn will be best, the LS may allow more flexibility in some situations that lack good corners. Some here have both just to cover every situation!

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Let me simplify a bit to put things on the one page. And I'm talking about the classic K-Horn, Belle, LaScala, and Heresy.

Tweeter: K-77 in all. This is a combination horn and driver. They are the EV T-35. There are some variations in the driver but this is a minor issue for this discussion.

Mid DRIVER is, in all the K-55. This is the thing which makes the acoustic signal and screws on to the horn. There are various K-55s but they're close and again minor for this discussion.

It is the mid HORNS which vary.

The K-400 horn is used on the K-Horn and LS.

The K-500 horn is used on the Belle.

The K-600 horn is used on the Cornwall.

The K-700 is used on the Heresy.

The numbers on the horns generally indicate the lowest frequency to which the horns function, well. This is about 1.4 times the Fc of the horn (where in theory it stops working). The bigger the horn, the lower the frequency.

Why different? The smaller horns are used in speaker boxes which are smaller front to back. Generally (very generally), this lenght scales with frequency.

Crossovers vary in the systems in two ways.

1) They accomodate the varying lowest freq. of the mid horn.

2) They accomodate the lowering efficency of the bass systems. The K-Horn, Belle, and LS are horn loaded bass. The CW bass reflex - port is about 3 dB less efficient. The Heresy sealed box is about an additional 3 dB less. Therefore the mid and tweeter levels have to be knocked down (in the same amounts) with the autotransformer to match the output of the bass system.

The above is the Big Picture.

Gil

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Wow, thanks Gil. This explains everything very well. Thanks for puting it in regular person language as I'm not an electrical or sound engineer. One more question for you if you don't mind, does the length, depth and width of the horn make a difference on how far the sound is projected out distance wise and does it make a difference with loud volume capabilites? Thanks

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Thank you for your kind comments. I'm trying to simplify the issue and making a complicated issue simple is a bit difficult.

Basically, the family of exponential midrange horns in the Klipsch mentioned are the papa bear, moma bear, and baby bear of the family. Well, there are actually four, but you can see how it goes. I would say that once you get above the lower limit, they are acting fairly the same way for purposes of this discussion.

You have asked, in the last post, several questions.

Generally, these horns all have the same effect of loading the driver K-55 to make sound more effectively. The major difference is the lower frequency. But you ask about volume (sound pressue) capabilites. Roughly, they are the same. We get the same horn loading advantage of taking power off the driver.

When you ask about dimensions of the horn as an influence, there is a lot of difference.

This has to do with the radiation pattern of the horn. You may have seen horns described as acoustic lenses. As if they can focus sound. That is almost correct. Somewhat like a Maglite flashlight.

But. you see a horn which has a mouth (the big end) which is 4 inches tall, and the mouth is 8 inches wide. You think this works like there is light bulb in the back and of course the vertical pattern is narrow and the horizontal pattern is wide, as far as light.

Actually, this thinking is all wrong in practice in acousitics. This comes from antenna theory. If you want a narrow transmitted beam, you need a big antenna. Which means you need a bigger mouth in the vertical direction and a longer horn.

I do realize this does not quite answer your question. But suffice to say that size is a big issue in getting a lenses to work.

This wave mechanics is difficult to explain but is everywhere in the physical world once you get in tune to wavelengths.

Consider that telescopes which look at narrow parts of the sky must be very large. There is reciprocity there.

Gil

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If there is one subject I would like to have a much better grasp of, it is wave theory. Understanding crossovers better would be nice too! Thanks for the posts, Gil.

And just to show there's more than one way to skin a cat (as my dad was fond of saying)...

post-3900-13819329620774_thumb.jpg

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Well, I guess I got some attention here. Let me be pedantic.

The first thing about wave mechanics is to recalibrate your head to what I'll call "wavelenght land." I was going to put this up as a companion to mas' comments on Flat Land. Better that we don't confuence the two. mas gets too complicated.

The first issue is just mathmatical inversion of what we see as our sound sources. The higher the frequency, smaller the wavelenght.

One easy benchmark in audio and air is that 1000 Hz signal has wavelenth of 13 inches, about 1 foot. 10,000 Hz has a wavelenght of 1 inch. 100 Hz has a wavelength of 10 feet.

Do not get out your calculator to find the exact numbers. You have to get the big picture even if the numbers are not exact. It is very important that you see, or convert, these frequencies as-to wavelengths. It is very important.

Important Point: Wave mechanics always asks about wavelength. (That's why they call it wave mechanics!) You have to get into that "world." The 1 inch, 1 foot, 10 feet, is good enough for the big concept. The big concept is FAR more important than precision.

The next thing you have to do is look at a source of acoustic energy. Like your speaker. Say it is 1 foot wide in our world. That is about a woofer wide, or the mouth of a midrange horn. That is PHYSICAL SIZE. But things change in Wavelenght Land.

The most important thing you can understand is that the 1 foot dimension of physical size, varies in wavelenght land (which is also the inverse of frequency land). The 1 foot driver or horn mouth is one wavelenght at 1000 hertz. But it is 10 wavelengths at 10,000 Hertz. It 1/10th of a wavelength at 100 Hertz.

The paragraph above is the MOST important first step in wave mechanics. You have a physical size which you think is constant. But, as frequency and wavelenght of the signal varies,it becomes bigger and smaller._

= = = =

This is somewhat an Alice in Wonderland situation. (Please excuse if I'm being condescending for hi tech guys.)

But, if you (Alice) says my Heresy driver is 13 inches wide (or close to that). The Red Queen will question: At what wavelenght is that in Wavelenght Land? Alice will say, At 10,000 Hz, it is 10 wavelenghts wide. At 1000 Hz it is 1 wavelenght wide. At 100 Hz, it is 0.1 wavelenghts wide.

The Red Queen will say Alice is correct, if we're in Wavelength Land. Alice's 'Heresy has expanded and shrunk getting 100 times bigger from the smallest in Wavelength Land.

Of course in physical dimension land, it has not changed at all.

Gil

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The K400 is a 90 degree horn. The Khorn shape forces it into the corner, therefore NO early reflections off of side walls. In my mind, this is a very clear advantage in addition to the low bass of the Khorn, extreme efficiency, and the height of the drivers. To say nothing of the fact that they use up real estate in the corners of a room which is largely wasted anyway.

They literally disappear.

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OK, I think I grasp wavelength and frequency, but what about directionality of sound waves as they relate to driver / baffle size? Why is a 5" cone more directional or beamy at 5000Hz than a 1" dome. It seems logical to me that once a tone is generated and a wave begins to expand from the driver, it should behave the same regardless of driver size. I suppose the easy answer is because the larger driver is so much greater in size than the wavelength be produced, but that does not tell me why is this so. The answer to this may be over my big, fat head guys, so aim low!

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I spent the day thinking about jdm's question, and working up a good explanation. Most of the explanations were really "begging the question". I.e. that the answer about antenna size is just a rehash of the question -- that bigger is better.

Let me point out that there are analogies between electromagnetic waves and sound waves, but they are not the same. Otherwise relativity and the like would apply to sound, and it does not in fact.

I believe the answer is a consideraton of how the air molecules (gas) work.

Sound is typically analyzed as having two components of potential energy. One is pressure, where the molecules are bunched together and thus are dense in a given volume of space (inches cubed). The other is velocity (actually called volume velocity).

The molecules are spring-ey in that when they get close; they bounce off each other, somewhat like billiard balls. There are glancing blows where one molecule can send another off at an angle. This is an important point of discussion. It is like a moving car hitting a stationary car.

You can see how these two components play off each other. If the molecules are close together (and form pressure), they are going to be more collisions and they start moving. But when they start moving (volume velocity), they hit stationary molecules in the next region, and tend to bunch up, causing more pressure in the next region. Then the pressure (or density) causes more movement.

This is why sound propagates from high pressure to low pressure. Because of the possibility of a glancing blow to a stationary molecule or one which is moving in a random direction, sound can move sideways once it is out in open air. In a way, it radiates in all directions.

- - - - -

I think that is the center of the question. If sound radiates in all directions once away from the diaphragm because of collisions, how can it beam?

(Well, let me go back and say the spreading out is not exactly random, it is statistically away from higher pressure (density). Again, pressure or density causes more collisions and naturally they encounter fewer collisions where there is lower density, and thus velocity is that direction.)

- - - -

The answer to beaming is to consider that larger radiators influence more molecules. The surface is moving in phase everywhere and thus the large numbers of molecules are all going in the same direction from the initial hit. This means that a given molecule is not going to be able to hit the molecule just next to it. The one next to it has the same speed and direction. So there is no "closing speed." Moving in the same direction with the same speed is the same as saying they are not getting closer.

But, you say, these "in-phase molecules" must hit stationary molecules to give glancing blows sending them off in random directions. True. But statistically, for every left glancing blow there is a right glancing blow, and those two are likely to collide to go forward, again, in the same direction. It is not really random because the collisions occur at the same time (remember they are in step with each other). So the march of molecules in one direction is recreated.

- - - - -

Another way of looking at this is to consider the periphery of the localized organization. That is where a forward moving molecule is most likely to encounter a stationary molecule, or one moving in a random direction. The area of the disk of moving molecule (set in motion by the diaphragm) goes up as the square of the dimension of the disk. Pi*R*R. But the periphery (where the stationary or random molecules are located) is the circumfrence with is just Pi*2*R.

This means that when we have a big diaphragm, we create more forward marching molecules, in phase. The number of targets which could go off sideways at the edges, is relatively less.

- - -

This in phase motion is somewhat like having a cars on an 8 lane highway going in one direction. They can't collide with cars going in the same direction (no relative motion or closing speed) and only the cars at the sides can collide with the stationary signposts at the edges. The more lanes we have (bigger diaphragm), the lower the percentage of lanes near the signposts (random collisions).

I think that is the correct answer.

Gil

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Whoa there, I'm gonna have to chew on this one awhile, Gil! [8-)] I can see how any pistonic driver would tend to radiate sound in a hemispherical pattern due to the air molecules at the driver's edge being impacted from just one side, thereby pushy them outward, more or less perpindicularly away from the pole of the driver's motion. (Your billiard ball analogy) But I still don't see why that omnidirectional radiation narrows down to a highly directional beam as frequency rises. I know it relates to the diameter of the radiator, but why? What's going on here?

I think I'm gonna have to do some research unless, Gil, you can perform a Vulcan mind-meld via dsl! [co]

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It sounds like a narrow beam has proportionally more surface or perimeter compared with a wide beam, so a narrow beam of pressure waves is more affected (or easily deflected) by the surrounding air, tending to spread out sooner than a wide beam, which has many more air molecules in its larger center. Accordingly, the wide beam's center would be more protected from interaction with the surrounding air, so it would tend to continue in a straight line for a longer distance.

As for the frequency question, I'm not too sure.

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OK, I think I grasp wavelength and frequency, but what about directionality of sound waves as they relate to driver / baffle size?  Why is a 5" cone more directional or beamy at 5000Hz than a 1" dome. It seems logical to me that once a tone is generated and a wave begins to expand from the driver, it should behave the same regardless of driver size.  I suppose the easy answer is because the larger driver is so much greater in size than the wavelength be produced, but that does not tell me why is this so.  The answer to this may be over my big, fat head guys, so aim low! 

 


I once had a simple chart that explained this quite well....couldn't find it.....but read "Huygens Principle" at the below link.  It's pretty good and covers both ends of this omi-directional as well as beaming and intrestingly, also mentions factors that vary based on the type of driver architecture used.  Not to discount any of the comments already posted.

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