Smiths 1200 htz horn x over

[swilce]

I have some smiths 1200 htz horns which I am planning to use with some JBL 4508 bass enclosures.
The bass enclosures are not recommended to be crossed over above 800htz.
Does anyone know the usable range of the smiths horns, as I am hoping to take them down to 800htz but not sure how they will sound.
I havn't bought the compression drivers yet but am panning on using TAD or JBL. 800htz wont be a problem there, its just the horn I am worried about.
I am new to horns so excuse the question.

[Pano]

I'll bump this, tho I don't know the answer. The smith horns are a bit odd.
Given the 1200Hz rating, getting to 800Hz clean seems unlikely. Or if you do, the roll off under that will be very fast and distortion high. Well, with more normal horns, anyway.

Anyone here use the smiths horns?

[pos]

Is it a 2397 type smith horn, or a smaller one?
The 2397 can be used down to 800Hz without major problems (Westlake uses its version down to 800Hz in its designs).
What woofer are you using in the 4508? You could use it horizontally and do something like this:
TM-3

If you have to cross higher than 800hz then a 2.5 design would be good, with one woofer going up to 1200Hz (or as low as you can get the smith horn to go) and the other one LP filtred with a simple 6dB filter around 150Hz, as in the 4435 or everest2. You would have to lower the box tuning.

Be aware that the smith design is not that good above about 8khz, as each exponential section starts to beam, resulting in noticeable lobes in the polar response.

[EarlK]

Smith Horns have long been a topic over at LHF ( Lansing Heritage Forum ) .





Your best bet is to search (in the poster box ) for posts from " Mr. Widget " / while typing "2397 " into the topic box ( there are 5 pages of results ).

<> cheers EarlK

ps ; One can see that a 1200 hz recommended crossover point has some good "science" behind it .

Here's what Widget ended moving to for years of smooth listening ( TAD 4003 on TH-4003 horn )

[kevinkr]

Originally Posted by pos

Is it a 2397 type smith horn, or a smaller one?
The 2397 can be used down to 800Hz without major problems (Westlake uses its version down to 800Hz in its designs).
What woofer are you using in the 4508? You could use it horizontally and do something like this:
TM-3

<snip>

Be aware that the smith design is not that good above about 8khz, as each exponential section starts to beam, resulting in noticeable lobes in the polar response.

A friend loaned me a pair of JBL 2397 for long term evaluation and I can confirm that they work quite well over a range of 800Hz - 8kHz in a small domestic listening environment short throw (About 10' - 12') in my case.. High SPLs and longer listening distances (not more than 30') and you should cross over above 1kHz. The drivers are JBL 2440 with 2445 JBL diaphragms installed.

Orientation, height and listening distance are more critical in terms of the sweet spot than I initially suspected. Although they sounded pretty good in most listening positions there was a strongly pronounced sweet spot in my system where they sounded a whole lot better, and it was about a foot or so forward from where I was expecting it to be..

[kevinkr]

This is the most complete set of drawings I have ever seen for a Smith Horn, thanks for posting it here.

These aren't too hard to build, and building a really nice pair should cost significantly less than a pair of good used JBL2397..

Note that you can often get the 2328 throat adaptors for little money on eBay saving you the trouble of having to build your own. (Just get them first and make sure to build the Smith clones so that they will fit.)

[swilce]

Thanks for your fabulous replies. I am using JBL 2225J on the bottom end but am considering purchasing some ATC SB75-314 SC, instead,( pricey but fabulous drivers). I bought some JBL 2440 compression drivers, and am now thinking about a smaller horn and super tweeter to cover 11Khz and up as the 2440 slopes of pretty quick. I will see how it goes. Thanks for the comments, I will post images once I have completed the cabs

[Robh3606]

A JBL 2405 Slot tweeter is a natural used to extend the top end of those horns. Very similar dipersion pattern as well

Rob