Horn Tweeter Question

[VW1974]

I’m looking to build a bass guitar cab with a horn tweeter. I’ve been looking however haven’t found an answer to my question. I’m thinking about using the Eminence PSD:2002-8 horn tweeter which does not come with a throat horn. My question is does each throat horn change the response curve of the tweeter? I know it will affect the dispersion, but can I use the manufacturer’s supplied response curve and trace that to plug into PCD? Will it matter a lot on which throat horn I get? Any suggestions?

FYI, the bass guitar cab I’m thinking about modeling would be using 2 Eminence Delta Pro-12A. I’m not set on the Eminence PSD:2002-8 tweeter so If anyone has a better suggestion let me know.

Thanks all!

[Sidi]

have you considered the fEarful ?

http://greenboy.us/fEARful/

[donprice]

My question is does each throat horn change the response curve of the tweeter? I know it will affect the dispersion, but can I use the manufacturer’s supplied response curve and trace that to plug into PCD? Will it matter a lot on which throat horn I get? Any suggestions?

Change the horn and the the frequency response changes. Some manufacturers give curves with the drivers mounted on a particular horn or waveguide. Some don't.

Does that really matter for a musical instrument application? A little weirdness in the in the response just might give you the killer tone you are looking for.

[wg_ski]

For this type application, you generally run the woofer(s) full range, and just "bring in" the tweeter where it sounds best. Usually a lot higher in frequency than sensible speaker design calls for, but it's what is typically done. If you wanted to design the cab flat, you'd need the .frd and .zma for that driver on that particular horn. Horns not only alter the response, they alter the impedance as well (perhaps in between the pass and stop bands if you cross below woofer breakup).

[mdocod]

My understanding is that, yes, different horns will modify the response. In real world applications, the differences can range from very important to completely unimportant depending on the goals of the system. For a live sound reinforcement device, especially with EQ options available, I'd say that the effects of different horns on response is not an issue.

If I understand correctly, different amounts of controlled dispersion will effect sensitivity... That should be taken into account. If you're going to go through the trouble of having a horn involved in the box, I suggest picking a proper x-over point, such that the natural dispersion of the horn selected, will match that of the woofer at the x-over point. For a 12" woofer paired to a 60 degree horn, that would be around 1.4Khz. IMO anywhere from 1-1.8Khz is "fine" to meet this goal close enough. I would not personally suggest running the woofer "full range" as previously suggested. That would create undesirable hot spots.

Regards,
Eric

[VW1974]

Thanks all for the replies!! I think I have enough to go on. I'll look into a horn driver that shows the response with a given throat horn.

The woofer I would like to use, Eminence Delta Pro-12A, looks like it has a useable frequency up to 4000hz. Since this is going to be for a bass guitar what crossover point should I shoot for? Should i go with a lower like 1800hz or higher like 3000 hz? Obviously this will depend on the tweeter but I'm just looking for something to work from.

I'll work on a design through PCD in the next few days and post 'em.

Thanks again

[mdocod]

Running a 12" out to 3-4K is not something I would do. At 4K, a 12" driver will have about a 20 degree "beam-width." To make matters worse, most 12" drivers are going to have a hefty bright breakup node filled with distortion somewhere up in that 2-5K range.

[biscuitbarrell]

Curious. Just how often does a bass guitar even approach 4Khz?

[Sidi]

harmonics and string/finger string/plectrum interation reach past 10k.