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High Efficiency Speaker Asylum Need speakers that can rock with just one watt? You found da place. |
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High Efficiency Speaker Asylum Need speakers that can rock with just one watt? You found da place. |
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In Reply to: Re: prior art posted by Bill Fitzmaurice on May 11, 2005 at 05:33:18:
Hi Bill, Guys,A problem with using a vented system combined with any significant acoustic loading is that the box / port resonance you are depending on is too greatly damped as soon as any significant acoustic resistance is placed on it. The horns acoustic resistance could be likened to box losses in a “normal†vented system so far as its effect on “Qbâ€.
This approach would work when the horn was pretty much out of the picture at the low cutoff as to not load the port significantly.Part of the goal of the tapped horn was to have a condition which allowed the acoustic source resistance of the driver change as a function of frequency. Also (the part that makes it work) is to do so in a fashion which (as much as possible) off sets the changing radiation resistance the horn presents, as it nears the low corner. These would tend to have a less or not droopy response as one goes down in frequency.
Here, unlike a “normal†small horn, the driver does not become a direct radiator until well after the low corner and does not show the 180 degree phase shift / lag associated with a vent assisted low corner (in either a vented horn or vented box) but rather is more resistive than even a normal horn of the same mouth size.
So far as “howâ€, you guys are generally on the right track and nibbling around the edges and like one of the other posters, I also got the idea from what I tried from something I saw in the Unity horn. I probably should keep the details “quiet†a while longer, at least until they know for sure at work that another Speaker Company or two has bought one.
So far as prior art, I have compiled everything I knew of in the application and now it is a coin toss as to “if†it will go through easily or hard or if I get an examiner that really should be in another field. I don’t bother to write patent application drafts unless I think there is a decent chance it is useful / novel from a patent perspective.Bill, I know you like small bass horns for live sound, today or tomorrow there will be measurements for a new tapped horn at the web site. It uses 1, 15 inch driver and is a tapped horn. Ivan measured them yesterday out in the parking lot, 4 are 50% efficient or better from about 38 Hz to 175 Hz ( 109 dB 1W 1M equivalent or more, this was measured conservatively at 100 W RMS slow swept sine, half space ground plane at 10 meters).
Notice how flat it is, there is no ripple in the response, the acoustic phase and so group delay are both near zero.Got to run,
Tom Danley
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Follow Ups
- Re: prior art - tomservo 09:53:48 05/11/05 (3)
- Re: prior art - Bill Fitzmaurice 10:32:52 05/11/05 (2)
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