Critique my Design - 8th Order Bandpass

The objective here is a pro-sound sub useable from 40hz upwards, with a net volume somewhere around 10 cubic feet.

The driver is a Planet Audio FU18, which is a clone of the old Cerwin Vega Stroker subs. It's a dual two ohm voice coil, so the power plot is really 2 watts, but I think the efficiency is pretty good anyway.


I anyone has the inclination to have a look at the Hornresp file, it would be very much appreciated.

Screenshot 2023-07-17 090737.png


Screenshot 2023-07-17 091035.png


Layout will be pretty well like this picture, but the upper chamber will have 4 ports passing through to the lower chamber to symmetrically load the woofer. It's an old speaker and I don't know that it has the strongest cone int he world. Two ports will simply be holes cut in The 17mm plywood used for the build for ease of construction.





Screenshot 2023-07-17 091938.png
Screenshot 2023-07-17 092227.png
 

Attachments

  • FU18_8thBP.txt
    2.7 KB · Views: 41
Looks like an interesting design you've got going there.
Are the specs you're using for the driver published specs or measured specs?
Leave some leeway in your design for tuning the vents, as some retuning might be required (I don't think the Hornresp 8th order bandpass model includes the effects of box losses.
If there's anything I'd change, I'd change the design so that the driver is vertically oriented, not horizontally orientated. A lot less possibility of cone sag then.
 
@Brian Steele thank you. 105DB efficiency is a 6db gain over a ported box for this driver.

The specs were measured with DATS V3. If I build the box, I'll do it in such a way that all three ports are accessible. The ones that are just holes in the ply can be made bigger or partially blocked off. The 4 long PVC ports will be made 8 inches or so short and extended with a socket end of PVC pipe. I should be able to modify all three ports once assembled.

I'll see if I can re-jig the layout so the woofer is mounted as you suggest. I don't want to take up much floor space, so it might not be possible, but it's worth a try.
 
  • Like
Reactions: 1 user