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KPT-415LF question


Dave A

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Wondering about using the top and bottom woofers instead of all four. Thinking to cap of the left and right middle pair and then also blanking one of the triangular ports on the bottom. Four woofers provide way more SPL than I need for a great system so my thought is rather than buying some woofers at $300 a pop to replace missing or damaged ones maybe I should just convert these into two woofer units and have spares. Has anyone done this?

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6 minutes ago, Dave A said:

Wondering about using the top and bottom woofers instead of all four. Thinking to cap of the left and right middle pair and then also blanking one of the triangular ports on the bottom. Four woofers provide way more SPL than I need for a great system so my thought is rather than buying some woofers at $300 a pop to replace missing or damaged ones maybe I should just convert these into two woofer units and have spares. Has anyone done this?

The box volume would be way off for 2 drivers I would think.  The distortion for a given volume would also probably double.  The 4 woofers purpose is to provide lower distortion than two drivers due to less cone travel for the same SPL.

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The same size cabinet is used for the KPT-884 sub, with just one 18" driver and open ports, so your idea could possibly work. Using half the drivers will reduce the max SPL, but for most applications, should sound similar to a 904. If you need to reduce the box volume, a block of Styrofoam can be glued inside a corner.

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Well the other option is to get the new DATS measuring thingy from PE and then look for a close match from Eminence.  If these woofers are like the ones in the 904's even when you have them cranked up loud the excursion is not much so I don't know how much worry that is. The cubic feet may be another story though but until I have a way to get the Thiel parameters of the driver I won't know. Looking like I will get DATS very soon. Talking with Bill H the other day and he mentioned that the 415 was split to run off two channels so  the amps could run 4 ohm. Taking them and using a jumper would make it a 2 ohm so that is a problem also. I did that with my only trial run playing these and it did not sound to exciting and I wonder if it was driving that Crown XLI800 too hard.

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5 hours ago, Khornukopia said:

Each of the 4 drivers is 6.4 ohms. Each parallel pair is 3.2 ohms. Using a parallel jumper across two pairs puts it at 1.6 ohms. That could cause an amplifier to overheat. 

 

I use a series jumper between the two parallel pairs to give the amp a safe 6.4 ohm load. 

OK I never thought about that but resistors in series add up so that makes sense.

 

4 hours ago, risingjay said:

Wish you were closer.  We could do a swap, 904LF's for the 415's. 😞

Before I do anything with these I am going to try the above suggestion for hookup and then I have a horn and some B&C DE-1095's I want to try on them. The DE-1095 is a 280 watt driver and I have used it with a horn lens elsewhere and have hope it might work here too.

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Easy connection for wiring these KPT-415 quad woofer pairs in series. Then with the speaker wires dis-connected at the amplifier end, I touch the wire ends to a 9V battery and watch that ALL the woofers move in the same direction together.                          (Don't use the 9V battery on the tweeters).

 

IMG_3793.JPG.e0d69f13181e8334b48d09b9da2cbd1d.JPG

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