Experts please help . . . what should my crossover settings be on my PPI Ax400 amp?

[bdonkersgoed 10+ year member]

Hey Guys,

I am trying to switch around my system, but don't know much about crossovers. My PPI Art Ax400 has a fairly complicated built-in crossover and I am not sure how to set it. It has six switches that determine the crossover's setting.

Currently I have my RE-XXX 6.5" mids running off the front channels of the amp (I was only using two of the four channels), and now I would like the rear channels to power my Focal Utopia's. Currently, according to the dip switches, my amp is set to "FRONT: HIGHPASS 70 HZ, REAR: HIGHPASS 70HZ" with just the RE-XXX's on the Front channel.

The PPI Ax400 instructions say:

Inputs:

 

On the Ax400, the internal crossover's setting will determine the function of the four inputs. Depending upon your application, it is important that you refer to the 'Adjusting the Internal Crossover Section' before proceeding. The rear inputs are not active when thee crossover is set in the high-pass / low-pass or dual high-pass mode. Refer to the Adjusting the Integrated Crossover Section for more information.

 

Adjusting the Integrated Crossover (Ax400 only):

 

The Ax400 incorporates a two-way, electronic crossover featuring 18 dB per octave slopes and 4 adjustable frequencies -- 70 Hz, 110 Hz, 260 Hz, and 300 Hz. The crossover is designed in a tracking configuation and only requires 2 channels of input when engaged.

 

You can select four different modes of operation -- 4 channels full-range, 2 channels high-pass and 2 channels full-range, 2 channels high-pass and 2 channels low-pass, or 4 channels high pass. Integral to this design is a set of RCA low-pass outputs. These outputs are always available to send a low-pass signal to another amplifier or signal processor.

 

The four different modes of operation will affect the number of available inputs. The following list details available channels (pairs) of input versus operational mode (Refer toAx400 Crossover Modes):

 

4 Channels full-range: 2 pairs - front & rear

2 Channels high-pass & 2channels full-range: 2 pairs - front & rear

2 channels high-pass & 2 channels low-pass: 1 pair - front only

4 channels high-pass: 1 pair - front only

 

Switching is controlled via a 6 position dip switch (located through the bottom panel of the amplifier). Five of the six control switches adjust the different functions of the crossover (refer to Figure D. above). The function of each is denoted by its relative 'on / off' position.

 

It is important to note that the low-pass outputs (RCA-jacks) are always availablee, and the front inputs are their signal source. The position of switch 2 & 3 will determine the frequency available at this output.

Does anyone know how I should set the crossover when I have the RE-XXX's hooked up to the Front channel "as it currently is" and the Focal Utopias hooked up to the Rear channel? My Utopias are in the front of my car, so is there any disadvantage to putting them on the rear channel of the Ax400? I just don't want to rewire that portion of the setup if it isn't necessary.

Thanks!

Bryan

Click to read more...

 

[bdonkersgoed 10+ year member]

Picture of crossover instruction sheet (sorry about poor quality):

http://img330.imageshack.us/my.php?image=crossoveraj2.jpg

Thanks,

Bryan

 

[bdonkersgoed 10+ year member]

As an update, I have put the crossover so that it is full range for all channels and then used the crossover in my Alpine CDA-9835 HU to eliminate the unwanted frequenies in the speakers. Is this an OK way to do it, or should I be using the crossover in the amp itself as well?

Thanks,

Bryan