mm465 / Alpine 7969 - 24db slope

[Jeff Kousal]

I have recently installed in a Mazda RX-7:

Alpine 7969 HU - 24db internal digital crossover. 80hz/80hz

Phoenix Gold ZX- 600Ti bypassed x-over running MM465 in front
(150RMS X 2 14.4v @4 ohm)

Phoenix Gold ZX- 475Ti bypassed x-over with 2) MM100's in rear
( 250RMS X 2 14.4V @4ohm)

The question I have is: When is it necessary to reverse the polarity given the 24db per octave slope? How do I determine this? Please explain.

This setup is very loud, tight, clear and highly impressive , but want to make sure all the final tweaks are done.

Signed,
Pepto User

[Kim]

Jeff,
The only way to tell if you need to invert phase is to listen to a disc that you know inside and out to see if you can detect a reduction in low bass frequencies. If there is a reduction in bass perofrmance then invert the phase of the subs. Most second order and fourth order crossover do invert phase. First and third order slopes are phase correct. But this is only part of the whole picture. There also can be a null or cancellation of bass frquencies at your listening position inside of the vehicle. This is where your "Golden Ears" come into play so you can fine tune the system to get the best possible perfrormance. Hope this helps.

Happy System Listening!!
Kim