Opposing loading of multiple driver tapped horns.. Why?
Having studied a lot of Danley Sound Lab’s tapped horns, I notice where he uses multiple drivers in one horn, he often reverses (loads the driver(s) with the cone facing outwards or inwards) half the number of the drivers with respect to the other half. IE in the TH812, there are four drivers inside each mouth, but I can see two of these drivers are loaded with the cone facing outwards, unlike the single driver subs, where the driver is loaded in reverse.
I’m wondering why this is. Presumably something to do with phase.
As far as I’m aware, this is not currently possible in Hornresp. So I’m wondering what the exact effect is.
Any ideas?
Having studied a lot of Danley Sound Lab’s tapped horns, I notice where he uses multiple drivers in one horn, he often reverses (loads the driver(s) with the cone facing outwards or inwards) half the number of the drivers with respect to the other half. IE in the TH812, there are four drivers inside each mouth, but I can see two of these drivers are loaded with the cone facing outwards, unlike the single driver subs, where the driver is loaded in reverse.
I’m wondering why this is. Presumably something to do with phase.
As far as I’m aware, this is not currently possible in Hornresp. So I’m wondering what the exact effect is.
Any ideas?
my guess: cancelling out asymmetrical behavior in the drivers at high excursions.
Peter,
Using a "V" shaped horn "stub" at the horn throat apex, as done in several of DSL's tapped horns like the TH-812 or the dual drive DTS-10 does allow for "push-pull" (one driver's polarity is reversed) mounting, though Tom Danley has expressed that the arrangement was not used for the "benefit" of reduced even order harmonics, but for the loading advantage afforded.
In Hornresp, S1 (or A1) is area at the throat end .
S2 (or A2) is the area at the midpoint of the rear (throat side) of the driver.
The “V” creates a larger volume at S1, than S2, that air volume stub may tend to smooth upper response peaks.
A "stub" can be (and is) also used on single driver tapped horns.
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In other words they fit better that way. If the driver is reversed so is the polarity so that they are all IN phase, so no canceling of any kind takes place. Unless you're just refering to mechanical non-linearities of the suspension and what not.
Imagine you have just a simple closed box with two woofers.
Now you flip one of them facing inwards, you switch wires on the coil, no change in phase. No change in fr response.
So why would you do that.
Lower distortion. Simple as that.
I have done it in my subwoofers. SL done it in his subwoofers. You can measure lower distortion now. Its simple mechanism of eliminating some distortion by canceling out some nonlinearities.