With a measured 20 Hz Fs/~0.2 Qts, all it lacks is some room/boundary gain and excursion, which is supplied by the extra driver/channel and a couple of corners. Four corner loaded 515Bs do a pretty good job of mimicing a basshorn until you want to start busting drywall seams. Anyway, the system does ~111 dB/16 Hz/200W in-room before thermal power compression sets in, or about what a single driver room sized folded horn will theoretically do at ~2W. My house is a flimsy stick built one with a floating floor though, so they could do at least another 6 dB in a concrete foundation brick n' mortar built one.

WRT its low Qt rising response, this can be either active and/or passively EQ'd. Mine are EQ'd ~flat 20-20 kHz and still close to 100 dB system eff. above ~40 Hz. Not going to compete with the 'big boys', but good enough for my well abused ears.

WRT size, I grew up around huge mono consoles, 7-8 ft^3 end table speakers and 3-5 ft^3 'bookshelf' speakers, so 20 ft^3 seems right reasonable to me for a corner loaded app, especially since they use to be 30 ft^3 before I cut them down. This is the price you pay for having eff. and wide BW.

GM

You're welcome! Yeah, a pair of Concert Grands is quite an auditory experience! I use to 'clone' their tweeter 'horn' concept using recycled radio/TV drivers to make large 'el cheapo' ~100 Hz 'multicells'.

Its faceplate says Sony TA3200F (early '70s), but according to a service tech it isn't one under the cover, so we assume it's a Japan spec version that he didn't have data on. All I know for sure is that it's a very low -fb/distortion/noise floor, ultra wide BW 120W/8 ohm class A-B SS amp that I prefer over any other amp I've used.

GM

Can you help to design an Onken cabinet for a 15" SG38WNS GOTO driver?

Thanks,

Ming

If you have T/S specs, and I need to know your amp's output impedance (not tap rating) if tube.

GM

Thanks,

Ming
mingsu@yahoo.com

Without knowing either the damping factor or output impedance of the amp, I can use a 'worst case scenario' of 4 ohms and the cab may be too big, which can be offset by damping the ports some, but without the driver's 'Vas' spec I could be so far off that you would have to stick an Altec or other known high Vas driver in it to make it work well. If it's more like a JBL or similar and it makes the cab way too small, then you wind up with a high Q midbass box with no LF output to speak of. For example, using an Altec 'worst case' Vas, the basic cab's volume (Vb) could be almost 23 ft^3, but with a JBL's low Vas, as little as ~6.2 ft^3.

So can you find out its Vas spec, or feeling lucky and want to pick a number? I also need the VC's DC resistance (Re) to figure the effect of the amp's output impedance on Qts.

GM

Thanks,

Ming