I read in speakerplans FAQ that a high EBP is good for horns. However this is not the case with this driver... The low Fs is needed for the horn to go low, but isn't a lower Qts would make it a faster driver?
It also doesn't have tons of BL, however Xmax is good..

Thanks for the help
Adam

By the way, we don't use the LAB12 driver anymore. Ours in an OEM driver that is essentially the same as a LAB12, but that is machined to fit our cooling plug. This makes a big improvement in thermal performance, which is really important in high-power basshorns. Since excursion is reduced by horn loading, the effectiveness of the woofer's cooling vent is reduced too. Our cooling plug approach is what keeps the motors cool in our 12π hornsub.

• Heat exchanger effectiveness

Also, what are your thoughts about qms ratings in different types of horns, in regard to sound quality?

It's all about what you want to do. If you want a midbass horn, use a lighter cone, by all means. It will give better output up into the midrange. But if you're looking for drivers to use in a hornsub, you probably wouldn't need (or even want) the HF extension. For a subwoofer, I would prefer a driver that does its best work down low and is robust enough to handle high excursion and current.

What are your thoughts about "how much is left" from the original driver's specs like response graph, efficiency etc?
I've seen how midrange drivers that are predicted to have different efficiency in HR are much closer or even the "lesser" driver had better efficiency in real life, when talking with people about results they've had with horn loading.
For a subwoofer, the inital efficiency seems to have nothing to do with the outcome after the loading.. For a midbass, how should I look at that? How should I look at xmax requirements for midbass?
Is there any importance to look at a driver's efficiency at 100Hz if I aim for a 100Hz horn?

Many thanks for your time
Adam

At higher frequencies, from midrange up, the diaphragm begins to flex. The cone no longer acts as a rigid piston, instead, parts of the cone become decoupled and operate independently, like smaller diaphragms with less mass. This makes the response at higher frequencies different than what a rigid piston would produce. It usually has more output than expected. Some cones that are pretty well damped have relatively smooth response in this region, but many become jagged up high. As a result, I find that midhorns should be built and measured to know the high frequency response. The Hornresp model does a pretty good job of predicting response at the low end, but it doesn't have the input data to predict what happens up high. That would require more sophisticated FEM models.

Damped = low qms = good for midrange horn?
(BTW, how does cone breakup come into play in a midrange horn?)

So, as you see it, for a midbass horn (up to 250), you would trust almost blindly upon simulations? No worries if a superior modeled driver is 6 db less efficient then another?

I gather, from a list of driver characteristics and people view about them, that it's generally a good idea to have a good BL/mass ratio (low mid and up).. What do you think about that?

About basshorn simulations, it's not that I would trust them "blindly", rather it is my informed opinion that the simulations track reality very closely. I think that's probably what you meant, but it is important to be aware this isn't blind faith. I've done a lot of simulations and I've measured a lot of horns, built as specificed by the models. Under about 500Hz (depending on the cone), the models are very accurate. At higher frequencies, cone flex prevents the models from being accurate because the models assume pistonic diaphragm motion.

How can I know how stiff is the driver?

BTW, didn't meen to say you trust things blindly - I trust you not to do that.. I value your work and word and am thankful for your time.

Adam

Replace that with Qms...