Hmm, he claims to have a L7 15D2, which has identical specs displayed in HR except with 6.28 ohm.......... As it turns out though, the 08S15L74 has some different specs, yet display identically in HR except for the 7.1 ohms. Wonder what the odds are on that?
GM
Sorry I didn't get those specs dug out of the manual yet. My plans seem to change constantly. It is one of the first L7s when they came out in 2002 I think. Way before they did the L5s. I had also been researching the lilmike cinema F20 but didn't want to buy a new sub. Then I saw parts express had their DVC15s on sale I got one and built that horn. Turns out the spider was not glued properly and was loose. So now I'm sending it back and wondering if I made the right choice. I'd still like to build this tapped horn too. Just wondered how simple it would be to lower the tuning frequency a bit and if it was advisable. I've never dealt with horns of any type or hornresp. I built the F20 since he did all the leg work and published plans. I know thats not on the DIY spirit.
Don't know, you need measured specs to be sure, but based on the published specs I have, it has a horn BW = ~7 - 99 Hz, so can go lower, though don't recommend lower than ~13-14 Hz.
Of course the lower it's tuned, the less peak SPL across its usable BW and the lower the first notch will be, so tuning it lower may require a lower XO point.
GM
Of course the lower it's tuned, the less peak SPL across its usable BW and the lower the first notch will be, so tuning it lower may require a lower XO point.
GM
Peak SPL isn't my main concern. I'm barely driving it at all in the ported box and its output is definitely decent. Like I said I'm very new to tapped horns am I correct in my thinking that a TH only had about 3 usable octaves? So a 20 hz tune is only good up to 60hz? That's not ideal but may not be horrible either. I have Polk rti1000 mains with the built in "sub" that will grab down below 60 rather well.
That design is not a true tapped horn. It's a tapped quarter wave pipe (TQWP), straight flare and EASY build since there are no angles to deal with. A true TH has a positive flare, is more efficient, and requires a bigger box for the same 19 hz tune. If you want a wide frequency response and smaller box, then a tapped-tapered quarter wave tube (T-TQWT) is what you want. T-TQWT's have a negative flare and are less efficient than TH and TQWP's. I built a T- TQWT for my L7 because I wanted 20-80hz. I would have built a bigger enclosure if I had bigger spare pieces of wood lying around. I'm cheap! My wife & kid bought the L7 for me for xmas in 2008. I would have NEVER spent $300 on a single sub for myself.
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How about 130dB's @ 20hz with 550w @ 8ohms (1100w @ 2ohms) in a room corner or van/suv???
16" W x 12" H to 16" W x 6" H internally for 11 feet. Double fold box with 0.75" stock = 35.25" H x 39.75" D x 17.5" W externally.
16" W x 12" H to 16" W x 6" H internally for 11 feet. Double fold box with 0.75" stock = 35.25" H x 39.75" D x 17.5" W externally.
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