AP5 Grey with AP10 bass wide Design

[gmg733]

All,

Greetings! I am thinking of building some two-way Mark Audio units using the AP5 and AP10 bass wide drivers. Does anyone have any plans in regards to this, done any testings, etc? They would server a dual role, 50/50, between music and home theater. A couple of my goals was to keep the crossover as simple as possible, 1st order if possible, and crossover around 200Hz as to not be in the predominant voice region. Having done some modeling in WinISD, I suspect the 1st order 200Hz crossover might be a bit aggressive design goal as you get into max cone excursion pretty quick. To that end, I was wondering if there were any recommended/proven designs out there. I did not find anything on Marks site for such a configuration.

Regards,

[Inductor]

Try 250/300Hz xover. Use the Rvc ~5/6ohm@300Hz for calculation of the xover for the AP5. Rvc ~7/8ohm@300Hz for the AP10. Plan for some BSC.

[keith_correa]

This is what Mark gave me when I had contacted him some time ago. Hope this helps:

"I'm going to give a you a simple design brief to get you going. It's based on the Alpair 10 Bass driver paired with the Alpair 5 grey. These 2 drivers match beautifully. The 2 box arrangement is definitely the best way to go:

Bass box - Construct from 20-mm MDF or Marine Ply (can be thicker material is desired).
1 - INTERNAL size - 380-mm high X 180-mm wide X 220-mm deep.
2 - Place the Alpair 10 unit at the top of the cabinet, allow 40-mm clearance from inside the cabinet top to the highest internal point on the driver. This allows for at least 25-mm of sound proofing above the driver.
3 - Place the port at front of cabinet, at the bottom, again with 40 clearance to allow for proofing material.
4 - Port size - 40-mm diameter X 140-mm long. This should give a port tuning frequency of 37Hz. But be prepared to experiment on its length.
5 - Use 25-mm of good quality sound proofing on all inside surfaces of the cabinet.

Tweeter box - Construct from 15-mm MDF or Marine Ply (can be thicker material is desired).
1 - INTERNAL size - 110-mm high X 110-mm wide X 120-mm deep.
2 - Place the Alpair 5 unit at the centre of the cabinet. Stuff this cabinet with soft wool proofing or very soft OPEN cell foam. Take EXTRA care to make sure non of the wool gets on the cone or into the driver.
3 - position this box on top and centre of the bass box. Use very short legs or some thin pads to keep any vibration low.

Crossover
Very simple 1st order - crossing over at 1500Hz
Alpair 10 Bass driver - use a 0.6mH inductor on the + to the driver. Try to find a good quality inductor with a low DCR.
Alpair 5 driver - use good quality audio caps to get a value of 25mf. Also you may need to add of 2 Ohm or 4 Ohm resitor if you find the Alpair 5 being overdriven. You just need the A5 to fill in the middle to top end, not too much, let the A5 do most of the work.

Be prepared to experiment. Much depends on the your room, amplication and so on."