Driver Choices

[CIGARBUM]

In my quest for the selection of a driver for wooden horns, I'm not sure I understand what I'm looking for. It seems that JBL would be a good choice if you can find them at a reasonable cost. The ones that I have seem used are the following: 2482, 2440, 2441, 2445, 2446, and for a 1" the 2470. The first five are 2", the horns I will be using are the 260 and 225. I am assuming, to take advantage of the wooden horn you want a driver that goes almost as low as the horn, the only driver in the bunch that goes to 300hz is the 2482, the rest are at 500hz. Am I correct that another way to compensate for not having a driver that goes as low as the horn is to use an extreme slope crossover.

There are probably other drivers that fit into the mix, as the BMS 4592, but the cost exceeds my point of dimishing returns, at almost $1000 per pair is more than I really wish to pay.

Would appreciate any comments and opinions on the subject

Thanks

CB

[seti]

Have you checked out B&C. I got two B&C DE82TN driver for $500. They perform very well. I'm using this from 600hz-18khz.

[CIGARBUM]

Seti, what type of speaker are you using the driver in?

CB

[kevinmi]

CB,

I got those Selenium 405D phenolic's in the mail today. They are quite large and heavy. The box with both of them in it was 40 lbs! Anyway, I hope to try one out this weekend to see how it sounds. My horn is a 210hz monster that I am building for my Khorns, and I'll be using ALK Universal crossover clones built by Gothover. I believe they cross at 400hz. I'll take some pics and post them this weekend. -Kevin

[CIGARBUM]

Kev, let me know how they sound compared to the high priced spread. My application will be for my DBB with a 225HZ wooden horn on top with Beyma on top. I understand the perfect driver would be the JBL 2482, but can't find any.

CB

[seti]

Seti, what type of speaker are you using the driver in?

CB

I'm using it with a K403 and Jub clones. It is the driver Roy and PWK chose. There were other horn designers who also recommended B&C drivers. The quailty is surprising. I'm a big fan after listening them for a few months.

[oscarsear]

I use the JBL 2482's with AlK's extreme slope crossovers on Khorns. For now I am using some P-audio horns but hope to be obtaining some 300K Edgar horns soon. You want the lower frequency of the horn about 1 octave lower than the ability of the driver. As I was informed you want the midrange to easily drive well inside the specifications of the driver/horn/crossover combination. The lower range of the 2482 does easily achieve the 400 Hz crossover junction of the extreme slope crossovers and is well above the lower range of my horns. It fits well and performs flawlessly in the 3 driver configuration. There is no distortion at any volume. Hard to describe the sound of the 2482. I have not heard other products (other than the stock Klispch midrange). It is solid, deep, warm..... all those nice terms. It is also huge. Personally I would only replace it with a JBL 2480 and they are even more scarce (like moon rocks). The 2480 is not even listed on the JBL website but they made them for their most demanding applications. I have 3 of the 2482's using one in a center mono channel. I am pretty durned tickled with the arrangement.

[kevinmi]

Kev, let me know how they sound compared to the high priced spread. My application will be for my DBB with a 225HZ wooden horn on top with Beyma on top. I understand the perfect driver would be the JBL 2482, but can't find any.

CB

CB, check out my thread on updates/ modifications-early review on Selenium 2" drivers and a couple pics of half-built wooden horns. so far I'm impressed with the Seleniums, but only have 1 built so far, so I can't hear the whole picture.

[JohnA]

CB,

You didn't specify your intended crossover frequency, so I can only stick to theory.

The optimum horn has a cut-off frequency at least one octave below the crossover frequency. This makes sure driver's diaphragm is fully loaded as the crossover reduces the energy sent to the driver. Obviously, if the driver is tough enough, or is not asked to tolerate high power, the rule can be fudged, like the K-55/K-400.

Manufacturers spec a minimum crossover point and power handling for their drivers based on a certain crossover slope. IF you don't send that level of power to the driver, OR you limit the diaphragm excursion with a steeper crossover slope (or both), you can lower the crossover point. I believe that is what Mr. Paul and Roy did with the home Jubilee. I don't know how to advise you on how to change the crossover slope vs.lowering the crossover point.

However, this article says the diaphragm excursion increases 4x for each lower octave. That matches the 12 dB/oct I've always read is required to limit cone excursion. I suppose you could increase the slope 12 dB/oct for each octave you lowered the crossover point below the recommended crossover point.