BillFitzmaurice.info

Flip a coin. The GRS looks like a real bargain.

That will work, but you double the build time, and if the panel placements aren't precise you won't be able to get the second side on. If you end up with a thin veneer use screws when assembling so you're not relying purely on the adhesive.

Chamber reducers are not used in the T39. The 10RS430 is not a recommended driver as it's far more expensive than twelves that have higher displacement.

It will make no difference. Horns don't work like guitar bodies.

The combination of higher Fs and lower Qes will kill the low end. There's nothing to be gained using a pro-sound driver in the THT, and much to be lost. The PD.1551nr1 isn't sub worthy, in any cab.

Nowhere in the plans is usable frequency mentioned because it's a red herring. What is listed is the Fs range, but what mainly determines the low frequency response of a horn is the horn, not the driver. SPL charts are posted for all the subs so you know which meet your needs and which do not.

The folds act as a low pass filter yes, but that's a good thing. It's one reason why THD is far lower than any direct radiator. However, when the distance between the panels and the bends gets longer relative to the wavelengths being passed response gets more ragged. Localization isn't an issue unle...

The only way to know is by testing them at a distance with and without the time align. There are factors that influence the result with close measurements. That's why I measure at no less than 2 meters, while Tom Danley measures at 10 meters.

Try it again at a normal listening distance.

Distance to the mic? Mic height? Ideally you want it on the axis where the two cabs meet. With the cabs that high and the mic relatively close you'll see some phase zits that should smooth out with distance.

The AT takes an eight or ten, but not a twelve.

Is it genuine Neutrik?

I used dado channels when I built the David prototype. It took considerably longer than simple butt joints, so I never did it again.

The TableTubas would be an upgrade, let alone THTLPs. The response and output of a horn is defined by the horn, not the driver, totally opposite to direct radiators.

There isn't, 18s won't fit, nor would there be any advantage to them. A horn loaded 12 will beat a ported 18, by a wide margin.