Hello,
New to the forum as I stumbled across a W7 home subwoofer project thread.
I used to have a 12 W7 in my car years ago with 1kw rms matching amp. It was great in a small car but my front room is 5 x 8m.
My current setup is a Sonos connect with coax out to an Audiolab MDAC. I'm using the XLR out for my active floor standing speakers (Adam Artist 6) and they are great but they roll off at about 60hz. I use my setup 50/50 music/cinema and I tend to like boosting the lower end. The MDAC has a L/R phono out to utilise which I plan to run into a DS Peaker Antimode 8033 stereo for EQ (also provides 3db gain to avoid straining the MDAC outputs.
So, here's the plan. Buy two 12" JL W7 AE's. Hand build two 1" thick and braced boxes and power them. As my towers are very fast (hail from Adam A3X monitors - 2 x 3" drivers each) I'm going to use sealed enclosures. The thread I stumbled across on here suggested 2.3cu/ft internal volume? Is this correct? The poster mentioned a vas of 0.7. That means very little to me as I have no idea how the physics works, just that a lower vas is fast, a higher vas is slower (more rumble for HT). Any guidance is much appreciated on the best internal volume for my room as the F112 Fathom (JL W7) seems smaller?
Amplification? This is the tricky part or so I assume? The impedance is quoted as 3ohm yet on the JL website it quotes 2.5ohm. Most plate amps are 4ohm. One person on the previous thread said the JL W7 has an impedance closer to 4 ohms?
Would a 1kw 4ohm plate amp happily power the sub? If so it simplifies everything. The 1kw plate amp is on BK electronics site. Top heading amplifiers.
I tried to post a link but the site won't let me as I'm new.
So, will that amp be ok or was the other person wrong about it being close to a 4ohm sub? He mentioned a different acronym to justify this but I've forgotten. Is 2.3cu/ft the optimum enclosure size? The other amp I can use is this one from the same company and it's 2 ohm stable - but more of a ball ache as it's a module, not a screw on plate.
It can be found as an MF module 1000 on the bk electronics site uk.
Would that be better? I could also use a Crown XLS2500 as it runs 2 x 1200w @ 2 ohms. Open to options.
Thanks for any help/guidance in advance.
Tom
JL W7 12 spec
Free Air Resonance (Fs)27.2 Hz
Electrical “Q” (Qes)0.514
Mechanical “Q” (Qms)7.807
Total Speaker “Q” (Qts)0.482
Equivalent Compliance (Vas)2.33 cu ft / 66.0 L
One-Way Linear Excursion (Xmax)*1.15 in / 29 mm
Reference Efficiency (no)0.2500%
Efficiency (1 W / 1 m)**86.2 dB SPL
Effective Piston Area (Sd)84 sq in / 0.0542 sq m
DC Resistance (Re)2.47 Ω
