Bass driver for SET tube amp

[frangus]

I am designing a 3 way speaker for a friend who has a 6AS7 SET tube amp and need some advice on the woofer alignment and driver choice.

Woofer size will be 12". He does not play music loud. Efficiency is important but I'm also trying to get a decent extension in the bass to around 40-50hz in a 90 litre BR enclosure (about 3.5 cu.ft)

Is there anything out there that would work well with a SET amp that can give reasonable bass and sensitivity?

 

[Brett]

There are lots of pro drivers that will do this. Not knowing the Zout of the SET and how that will affect Qt makes it hard to make any sort of recommendation. I think you're gonna need to get a similator, get onto USSpeaker and try some.

 

[frangus]

Thanks Brett.

The Faital 12PR320 models well however I have not taken the amp output impedance into account. The owner is going to ask the amp manufacturer for that information.

Cheers

 

[GM]

Once known, calculate effective Qts' with the understanding that at a ~0.403 Qts' the max flat vented alignment is Vb = Vas, Fb = Fs and that the pioneers considered a Vb = Vas/1.44 was the optimal size Vs BW vented alignment: Calculate new Qts with Series Resistor

That said, SETs are best with tuning to Fs regardless of Qts' and with a base Qts = 0.52, it's best suited for sealed or damped TL.

Oh, and don't forget to add in at least a 0.5 ohms for wiring, etc., to whatever the amp's resistance is.

 

[AllenB]

It's not too hard to measure output impedance. So we're assuming, a SET can have low Zo too.