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In the Forum: Horn-Loaded Speakers
In the Thread: Problems with horns: upper bass
Post Subject: Partial Disclosure For The Sake Of ClarityPosted by Dresden on: 11/21/2008
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I've only had the pleasure of listening to 'professional' horns (whatever 'professional' really stands for)--horn normally used in concerts and small venues.  (It was always so obvious to me--by listening--that the range of the horn-loaded 'bass cabinets' was being limited by the length of the horn [no equipment measurements immediately needed, since I'm very sensitive to Mid/Upper bass frequencies].)

I'll give you a basic idea of what the proposed design would look like:  two J-shaped horns back-to-back, as though it were a mirror image.  Thus the reason for the horn throat remaining the same--the drivers do NOT share the same throat, but instead each driver loads its own horn.  I'm sure the 'picture' is now clear, correct?

If you take into account the amplifying effects of nearby surfaces, the reasoning behind my approach for a Mid/Upper bass horn design becomes obvious.  One 'drawback' of this approach is the increased depth of the overall design, but it is one I believe I've been able to successfully accommodate (considering the dimensions) in the overall base design.

(I'll refrain from describing other parts of the overall design, given that it'll 'spoil the surprise' when the horn is actually built.  lol.  Plus, I may decide to file for a design patent on the horn [a design patent will only protect my commercial interests, preventing an exact design from being manufactured and sold without permission].  Nevertheless, I'm inclined to provide full design specs to the DIY community, since they have been a great resource in providing examples of what has and has not worked [provided my end design works at all, lol].  On another hand, patents can be such a frivolous process to impliment in an attempt to 'protect' anything, adding undue complexity and an imaginary sense of security at best, most of the time.)

In regards to a phase plug, the only reason I'm intent on implementing one is to provide a smooth reduction from the surface of the radiating area (the cone) to the throat.  I'm not interested in particularly concerned with higher frequencies being projected as a result of incorporating a phase plug, especially given the target range of 40Hz to 400Hz (500Hz dependant on the compression driver's capability).  I will be using an electronic crossover in the completed system, to attenuate any unwanted frequencies outside of the target range (the system will be an 'active' one), though the use of the crossover will be very judicious.  If the phase plug does help in projecting the higher frequencies in the target range in to any extent, it's an effect that will be most welcomed.

I do know that acoustically, given the target range, the phase plug may appear 'invisible' to the driver for a good part of the frequencies in said range, but it may still prove to be a positive in the overall end design.

Think of it as a consideration of 'no stone left unturned'.  lol.  I cannot prove on paper whether the time vested in implementing a phase plug will be a complete waste--the only way to be sure is to build the phase plug and test/listen to the horn both with the phase plug and with a conventional flat section in place of where the phase plug was, and comparing both tests.


 serenechaos wrote:

You're using a phase plug?  Why?  To try to get it to go higher? 
If using parallel drivers, and doubling Sd, it may be necessary to change throat area to not damage drivers... 

The third design type sounds quite different from the first two. 
In my opinion, so much better I've quit messing with the first two... 
Have you heard both type horns? 

"Compound Horn" is what I've heard many speakers with horns on both sides of the driver called... 
e.g. what I mentioned previously, & linked, what I've built,... 

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