Orientation of assymetrical tractrix mid/bass horn

[AllenB]

These larger floorstanding horns are often built with one pair of sides following the tractrix contour, and the other pair of sides offering a conical contour, more waveguide style.

I 'm interested in opinions as to which horizontal/vertical orientation you prefer.

[bear]

Imo, somewhat irrelevant which way it goes... a bit depends on how high you let it go.
But the flat side (conical) section would do better to match the floor, in all probability, since it looks more like an extension of that side, making the horn have a bit of better response in the LF (but not much). This assumes a direct contact with the floor.

Again, depends on what you mean by "mid" and how low of a "bass" horn it is.
It seems to me that if you are really going into the bass, then you do not want a tractrix, you want something that will extend lowest - more like a hypex? Or perhaps a longer folded horn, or a rear loaded driver (assuming ur interested in LF extension in the main).

Just my thoughts... others may differ, ymmv.

_-_-bear

[AllenB]

Hi Bear,

My thoughts have been pretty much that. The conical sides would hold a more consistent pattern and I pefer that in the horizontal....on the other hand, I'd like the flatter panel on the ground for the better half-space approximation as well as floor bounce issues.

The tractrix is a bit of a gamble. I'd rather a shorter horn but there's no free lunch, although tractrix has been done successfully before and isn't such a bad contour. I don't think it makes as much difference down here anyway.

But I do want horn loading in this band and not just pattern control. I'm flaring at 95 to 115. I'll probably do 115 and hijack a room mode to extend it a little. The shorter horn might be preferrable. I want to go beyond 600Hz.

[bear]

i said conical to the ground, if I wasn't clear...

There is no "pattern" to think about at those freqs in general...

Flare at 100 Hz will work to 200Hz in a usual Tractrix, with some room or floor coupling, it may extend lower, dunno... others may have practical experience in this specific sort of thing.

Horn loading, you mean 'gain', will depend on getting some compression, as the "pattern control" aspect will add some lift at the freqs where the horn comes into play, but if you have a driver with a "rising response" that will yield a flat freq response, then there is no effective gain over the freq where the horn has stopped doing much...

It should be ok, but the tradoff is really around the xover point that is chosen, and how that is handled. Personally I prefer to keep the widest range beyond the 300-3000Hz. band in one single driver (horn in this case) - say 200 to 4-5kHz. or better... which is likely impossible without a compression driver of some sort due to the throat dimensions mostly...

_-_-bear

[Brett]

My experience with three or four trax flares is that they tend to load to about 1.4x (root2) the design Fc. A hypex will load better lower than a trax for a midbass, especially if size is a consideration.

[AllenB]

Would you say this if they both had the same throat, mouth and length?

[bear]

yes...