So, the lengths of the 2 passages don't contribute to loading the cones to a lower frequency in any way, due to the passages being narrower than the speaker baffle openings? Would vertical expansion thru this region offer any compensation? What if the horizontal narrowing were made more homogenous with the addition of an obstruction closer to the mounting baffle (see attached)?
Bottom line, I've challenged myself to find a way to make the speaker baffle openings in this (or a similar) configuration act like proper throats.
Wayne Parham Messages: 18782 Registered: January 2001
Illuminati (33rd Degree)
They absolutely do contribute to loading the cones, and I would expect that one of the things they do is to increase acoustic loading at lower frequencies. The thing is it's hard to know without measuring or at least modeling. I'd model this device in Hornresp, or at least half of it (one side).
My intuition is the curved sections will act partly as front chamber and partly as part of the flare. They'll increase the overall length, which will help load at lower frequencies. If the overall area continually increases, they'll act more like "flare" and less like "front chamber." But if the area decreases, they'll act more like front chamber and less like flare. And in either case, the radius will affect the HF limit and probably cause some rolloff. You'll also have the combination of the two sound sources affecting HF performamce too.
But measurements trump intuition any day. You'll only really know what this device does after you've measured it.
It's tricky, trying to determine where the tipping point is by sheer intuition, but exploring the extent of intuition gives a better feel about whether to proceed with a physical investment.
My amateur intuition told me that I'd get the lower cutoff I needed (with the right driver), at the expense of some top end. I kinda knew that the constriction would cause problems. I'll tweak the concept a while longer; it doesn't feel quite right yet, tho it's close enough now for HornResp.
After kicking around my 2x10 horn design for awhile, I've given up on trying to get it to (theoretically) reach 1600Hz to mate with a coaxial 1" comp. Although I like the driver placement, I can't get away from the notion that I'm creating double front chambers prior to the 2 passages combining. Perhaps a better plan is to mate it with a larger format comp & cross in the region of 1kHz to 1.2kHz, then mount horn/driver on top.
I'm still hesitant to put any money into this project....
Unfortunately, I can't get the FR I need in a 1x10 straight horn that shallow. The LF Xover target is 150Hz. I'd either have to go 4-way (no-way), or vent the rear chamber. I've been wondering lately if the Delta 10A has a high enough Qts & low enough Fs to get away with venting? I currently own 6 Delta 10As, gotta do something with 'em! Over-excursion would be the main concern....
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