BillFitzmaurice.info

Hi all,
Hoping for some advice.
Can the tiltback simplexx 12 airhead be stacked safely on a regular simplexx 12?
And would that be a good idea for Bass guitar? Idea is to use matching 8ohm 12s in each, allowing full power from a 4ohm head if both cabs are used, but maintain the tiltback feature when just using one.
Cheers, Doug.

Hi and welcome to the forum

Yes, you can do what you’re thinking, and that would be fine for bass.

Just so you know, you would be working your amp harder, with greater power draw from the wall socket, with a 4 ohm load

I'd check to see how stable it is in tiltback mode when stacked though...

It's fine. FWIW 'getting all the power out of my amp' is a myth. When you stack two identical speakers you get 6dB of additional voltage sensitivity, and 6dB of maximum output, because you're doubling the cone displacement. The amp does put out twice the power, because the impedance is halved, resulting in a doubling of current. But that's not what gives the additional output. It's a byproduct.

Hi, thanks for both replies. Much appreciated.

Bill, I am only about half way to understanding your answer, but I am intrigued. Can you - or anyone else - recommend a a good book or other resources to learn about this. I know that it is not a trivial thing to develop real understanding, but I figure I've got about half a life time left so where do I start?!

Cheers, Doug.

If only, but there's not much out there that's not really technical. To make it as simple as possible, you have one speaker being driven by an amp by a voltage. That voltage causes the cone to move X millimeters. When you add a second identical speaker parallel wired both speakers will receive that same voltage. This causes both cones to move X millimeters, while the cone area is doubled. That gives a 6dB increase in decibel output. It's volts that determine how far the cone or cones move, not watts.

Thanks Bill. That was well pitched at my level

Hi again,
Is the airhead option included in the regular simplexx 12 design pack too? Or is it only in the tilt back?
Cheers, Doug.

There's an airhead option shown in the Tiltback plans, but since the Simplexx 12 is also 20 inches wide you could do the same with it, adding a rack mount chamber above the cabinet top.

Thanks Bill.