** Does Bigger mean better **

[Ritch]

My question is pertaining to Tractix horns used in the RF series.

I was comparing the horns used in RF3's,RF5's and RF7's.

The RF3 have a 1 inch titanium driver with a 6" square tractix horn.

The RF5 has a the same driveer in with a 8" square tractix horn.

Does this mean the the RF5 is more dynamic then the RF3 because it is bigger?? Both speakers use the same dual cones, but the crossovers are set at different values. RF3 @ 1975 hz : RF5 @ 2500 HZ. I would think the horn on the RF3 would be more dynamic is range then the RF7 based on these specs. ???

What to you think of these's two speakers.

[justin_tx_16]

i think it increases the sensitivity the larger the horn.

[TBrennan]

A bigger horn in itself doesn't increase sensitivity, to do that (for a given driver) you decrease throat size. This can increase efficiency but will narrow the passband and increase distortion. Efficiency can also be increased by using a driver with a larger diaphragm and horn throat. Like if going from a 2" diaphragm, 1" throat driver and horn to a 3" diaphragm, 1.4" throat driver and horn.

There are a couple of reasons at least for a horn to be larger. One reason is so that the horn will respond to lower frequencies. Another reason is for pattern control, with CD horns a larger horn, for the same frequencies, will control the pattern better. And the pattern wanted will greatly effect the size and shape of the horn for a given frequency range.

www.chicagohornspeakerclub.org

[WMcD]

My suspicion is that "dynamics" is only a small part of the issue.

I was also a bit surprized that the bigger horn is cross over to at a higher frequency. But there may be several reason for it.

Don Keele, the inventor of constant directivity horns -- at least in as far as giving design parameters, pointed out that coverage control depend on the size of the mouth. This follows radio antennea design. I'm an old "ham".

Essentially, if you want a tight beam, the mouth must be large. (Antennae must be large to get directivity.) Also, if you want to control the beam down to a lower frequency, the mouth must be large. Where there is "control" depend on the wavelength, which is another form of frequency. So a bigger mouth should allow a lower crossover; i.e. the lowest freqency or largest wavelength at which they "work".

Why does this matter in the first place? It seems that the tratrix horns "work better" because they are a form of constant directivity horn. They project the sound out of a somewhat narrow wedge. This prevents sound from reflecting off the room walls. Hence there are fewer sounds arriving at the ear, late. This is good for listening and clarity.

My initial guess is that the designers wanted more strict control.

However, Tom B. has a very good point. If the available depth, or horn length, is constant, the larger mouth, with a constant throat size, means the horn will not load the driver down to a lower frequency. So perhaps that was a limitation in the design.

Again, I believe that "dynamics" is not the prime issue. Within their working range, the horns are probably equally good.

We look at the crossover frequency differences and the numbers seem remarkable. Roughly 2000 Hz versus 2500. We'd like a 25% increase in our income. And a 25% cut would hurt.

However, it is not that much different in our way of hearing music. I may be wrong on this, but I recall that going from a C to an E is called "a third", e.g. three whole notes up on the piano, and the E is 1.25 times the frequency of the C, if we're talking a "perfect third." Someone will pop up and correct me.

The bottom line is that the cross over frequency shift is not that material to our listening. It may have been necessary to meet a specification, though.

Gil

[Ritch]

Thanks for the Info,

The reason for the question, I have listened to the RF-5 and I like the RF3 better. I Like to listen to Vocals in my music. I only listen to misic with my RF3's. For some reason I think the RF3's sound better in the mid's, maybe because the horn is set lower at the cross-over point and is a tighter horn then the RF-5.??

Ritch

[Colin]

Bigger is better, though it may depend heavily upon the room in which you are listening, but no matter, there is not a large difference. As the horns got bigger on the Cornwall, La Scala and Khorn, in my open room with the same equipment, I noticed a starling improvement in clarity, wider and taller soundstage, sense of space and imaging with female vocalist Diana Krall. Realism was certainly enhanced. Not significant to many others. A one on a scale where Stereophile recommended speakers are tens. But to me,. It was an embarrassingly obvious choice. I needed the larger midrange horns.

[JohnA]

Gil is almost always correct. However, I'd like to add one other possibility. A larger horn will load the driver to a lower frequency. If Klipsch is using low order crossovers (12 dB/octave) loading the driver to a lower frequency will increase it's power handling capacity. The lower cut-off of the larger horn means the driver doesn't become "unloaded" just below its crossover frequency. That means the diaphragm won't hit the phase plug and clack or shatter.