BrianInCO
Ex Member
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Your PPI are oonly 8 ohm? Thats part of the problem then, they aren't drawing as much power a dual 4 ohm coils wired parallel.
John C.
John,
That's true, but it's not a fantastic idea to run a Linear Power 2202 at 2 ohms mono, it's a voltage amp. I like my shiny rails of TO-3 transistors unblackened and the power supply toroid intact. The DB certainly was louder in the 4-Ohm mono isobarik configuration, but not in a flattering way, very boomy and uncontrolled.
To be fair, this is not a high budget project. I selected the PPI's because I bought them at an auction for $30 several years ago in mint shape, and they were just laying around in hard-to-tell-from-new condition.
All the components in my system, down to the wiring, cost less than $200 total. So I'm not expecting miracles, but it seems like it should do a bit better. I have a 15" CV Vega 154 that's going in there aperiodic as soon as I pick up the requisite parametric EQ and find the time to fab the box, so this was intended to provide some low end in the meantime and just be something to toy with a bit.
I played with it a lot over last weekend, several hours total. I will do some more movement of the insert and see how that changes things. Not sure cancellation is the issue, as I've moved the box about and fired the port towards the driver's seat (where it is now), towards the side trunk wall, and towards the rear of the car. I've tried reversing the speaker polarity. Some changes in the sound were obvious, but not much of an improvement. I'm happiest and it's the least boomy firing towards the driver's seat in the proper phase.
Here's some T/S params from the web, maybe this will shed some light on things?
* Size: 10" * VAS: 68.14L * FS: 25.24Hz * Impedance: 4/ 8 ohm * X-Max: 9.97mm * Power Handling: 500 watts (max) * Sealed Box: .5-1.0 cu. ft. * Ported Box: .75-1.25 cu. ft. * Displacement: .065 cu. ft. * Voice Coil: 4 Layer TIL * Peak Excursion: 17.25mm * Sensitivity: 89.64dB
It's a pretty robust driver, at least compared to more traditional woofers. It's not designed to be a W7 or something.
I'll play some more and report back, thanks to all for your replies!
Brian
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