Phase plug for cone driver in mid-bass horn design?

[mefistofelez]

I rather like Altec 515, consequently, I would like to use it in a mid-bass horn, covering frquency range from about 90 Hz up, ideally to 1200-1300 Hz.

It is my understanding (and please correct me, if I am wrong), that higher frequencies cannot be produced, among other reasons, because of cancellation effects. It is my further understanding (ditto about correcting it), that the cancellation effects may be aleviated by a phase plug.

I was, therefore, wondering if someone would know how to design a phase plug/throat assembly that would satisfy the above-mentioned requirements. Even better, would someone know any literature treating phase plug/throat assembly design?

Thank you,

M

[mwmkravchenko]

Yes you can do this. And yes there are places to get some of the theory. But having done this a few years ago. Build it and experiment allot and you will learn more with seat of the pants engineering than you will out of the references.

Start by listening to your favorite tracks of music using highs Ie cymbals acoustical guitar, if your into classical then try harpsichord music. Understand what it sounds like on a good set of head phones and then experiment with your loudspeaker set up. You may be surprised what you can and cannot correct for. And you will be much wiser afterwards.

Mark

[Ken L]

Originally posted by mefistofelez
I rather like Altec 515, consequently, I would like to use it in a mid-bass horn, covering frquency range from about 90 Hz up, ideally to 1200-1300 Hz.

While far from an expert on this subject -

a 1000 hz wave is approximately 13" long -

While I'm not familar with Altec model numbers, I'll assume that is a 15" woofer.

So a phase plug isn't going to come into play until the distance from the plug to the sides - would equal the wavelength -

I'n only guessing but my guess is that you're looking somewhere around at least 3k or more before a phase plug would begin to have any benefit with that driver, at which point you've run out of the response curve of the woofer, and is not int the band of the spectrum in which you wish that driver to perform.

I don't think I've ever seen a phase plug on a 12" or 15" woofer.

While there may well be some out there, at the moment I can't think of ever seeing a driver larger than 8" that had a phase plug.

Regards

Ken L