The final graph is available on the POC #2 page - see The Subwoofer DIY Page v1.1 - Projects : "Proof of Concept #2".
I wouldn't recommend this as a build unless you do a few mods, as I put it together to try out a few concepts and not as a "production" build. Bracing was initially left out on purpose, for example. Its performance suggests that even the bracing I subsequently added is not totally adequate, particularly before the first fold, and better results might be obtained by rear-mounting the driver and permanently fastening the top panel to the internal panel by a suitable bracing arrangement to cut down distortion-producing vibration at that location. The FR also suggests that a slightly larger mouth may produce better results. And with the DFD in place this is basically a 39 Hz tuned box with a 12" driver - not something you'd typically find in pro audio use. The THAM fold is a bit limiting too - for maximum path length, the box ends up having a square profile. Have a look at the Thorn F1 thread for an interesting "mod" that allows for greater path length and a box with a taller profile (more suitable for sitting tops on).
As for power handling, the POC#2 has done ok when paired with my 1200W car amp (effectively feeding up to 600W RMS into its 8 ohm impedance). If I have some time this week, I'll run some power sweeps with it fed by the amp to see what the distortion looks like at various voltages, to get an idea of what the peak voltage capability should be. Naturally it should be highpassed below Fb if running a lot of power into it (mostly because it will sound like crap if trying to produce frequencies below Fb).
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.