Originally Posted by Erich H
I've had some questions about the difference between the Definimax and the Delta Pro 12A models. Basically, the Delta Pro gets the job done really well for cheaper and has a bit more mid bass kick. For theater use, or in a 2.1 system with a subwoofer, it would be perfect. The Definimax model is pretty much the same, except it can also be used full range when needed. The Definimax has a shorting ring which is suppose to make a cleaner sounding woofer. At volumes used in your house, I'm not really sure if it's noticeable or not until I hear them side by side. If I was making a choice, it would likely be based more on whether I wanted that extra mid bass punch or the possibility of running them full range or not.
Maybe I should clarify the differences. The Definimax woofer has a shorting ring in the motor and nonlinear distortion measures about 10dB lower than it does on the Delta Pro 12A and other similar woofers. It also has a longer Xmax at 6.4mm and a lower Fs.
My goal with the Definimax version was to design a system at a reasonably modest cost that could approach high-end audiophile performance, run full range with bass into the mid 30’s in most rooms, and have very linear frequency response. It’s lower distortion, longer Xmax, and lower Fs give it superior low bass performance. I believe it met my goals and is a speaker of fairly high-end caliber that approaches or matches the performance of some systems that cost many times the cost of this speaker.
Yes, there are some other Pro-sound woofers with more Xmax that also have shorting rings in the motor, but most of them cost quite a bit more, and I felt if the kit was too expensive very few would choose to own it. Also, I have worked with some of these woofers in the past and their bass performance can sometimes leave a bit to be desired. A lot of pro-sound drivers increase sensitivity at a sacrifice in bass performance by forcing Qes too low by simply increasing motor strength and lowering moving mass. Eminence did not do this with this woofer and as a result it is capable of some decent bass performance. I designed a very expensive commercial speaker that uses the JBL 2206H, and the Definimax compares very favorably to it in my opinion in practical terms, at a much cost . Here's the in-room response and the input impedance:
If you want a full-range, high sensitivity (95dB), higher impedance (8+ Ohms) two-way with waveguide, then I highly recommend the Definimax version, which I have called the “Zephyr”.
The version with the Delta Pro 12-A I have called the “Tempest”. It is a bit meaner by nature. It does not have the shorting ring in the motor, so its nonlinear distortion is higher. However, I can’t say that I can audibly recognize this by listening. It has a shorter Xmax, so it is more displacement limited in bass output, and it will not go as deep. But, it has almost 3dB more sensitivity. I used that extra sensitivity to favor the mid and upper bass in its response. The Tempest is technically not as flat, but to my ear sounds very satisfying, if not really downright enjoyable. I listen to a lot of jazz and classic rock and I have played this speaker full-range with no sub and was very happy. It’s a great rock speaker since a lot of rock music doesn’t go as deep as some people think it does, and this speaker reproduces it with an excellent sense of realism. It is a also a very economical speaker. Here's the in-room response of the Delta Pro 12A version:
In fact, these two versions offer the most bang for the buck of any speakers I have ever designed in a couple of ways. First, they are large and efficient, and fairly full-range and offer a lot of sound for the money. Second, in the world of high efficiency tube-friendly speakers, if these were finished in a beautiful cabinet with excellent craftsmanship then they would rival in every way systems costing many times their price.