High Efficiency Speaker Asylum: Re: Eminence LAB 12 drivers by Wayne Parham

Hello again John!

You wrote:

> > The thump I get from the horn is capable of rattling my ribs,
> > the reflex doesn't. The reflex does sound magnificient, but
> > without the acoustic power. Man, do I like power!

Yes, I like a lot of dynamic range too. And I like horns. But I've found that there's more than one way to achieve most goals, and to expect a portable basshorn to generate output below 30Hz is unrealistic. In this region, there is little choice but to deliver a lot of power to a direct radiator. Permanent horn installations may be large enough for good performance below 30Hz, but in the case of smaller, portable horns, they just aren't loading the diaphragm at this frequency so they are acting as direct radiators anyway.

The sound of a good basshorn is excellent. But we're beginning to become self-deceived when we talk about the performance in the bottom octave. The fact of the matter is that 20-30Hz output falls off sharply in a basshorn the size of a refridgerator or even twice that size. And supposed time alignment is even more problematic, because we have a fixed delay from path length, and moving delay in the lowest frequencies where the horn unloads and begins to act as a direct radiator.

> > I'm not trying to discourage your posts, but I think you must give
> > Tom his due. I wouldn't be listening to this fabulous woofer if
> > Tom hadn't been on the scene. In fact, I'm going to purchase
> > another 6 of these drivers this year just in case they are discontinued.

Eminence makes great speaker components and they'll provide anything you want, within reason. In fact, until recent years, their product offering has largely been components made to order. They have over five thousand speaker specifications on file, each corresponding to a custom part made as a request for a particular need. So frankly, I'm not comfortable iconifying one particular part in a family of similar components.

Personally, I'm impressed with Eminence's new Magnum series parts, because a lot of attention was paid to making the motor's flux field more linear. They've used a copper shorting ring like JBL's Flux Stabilized Magnet Structures and this technology delivers significantly better 2nd and 3rd harmonic distortion performance. So I expect that this technology will make its way into their other product lines in the near future.

I don't know if the LAB12 part uses one of these flux stabilized motors as its core technology, but I think that's more important to overall quality than T/S specs modifications using diaphragm weight or slight suspension changes. Eminence can easily tailor diaphragm weight and suspension of any speaker to suit the needs of the customer, so the core product chosen is really the primary determinant of quality here. Whatever motor technology was used to base the LAB12 on is the most significant feature of this part, not its particular tuning by weight or suspension features.

Take care!

Wayne