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Re: Favorite flavors [message #17461 is a reply to message #17454] |
Sun, 23 January 2005 20:29 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
Earl Geddes
Messages: 220 Registered: May 2009
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Master |
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Wayne You are falling into the common trap of assuming that waves follow the walls of a horn simply because you want them to. They don't. For instance at frequencies where the wavelength is comparable to the horn mouth the directivity is substantially smaller than the wall angles. It is only when the mouth is much larger than a wavelength that the device even begins to get CD. Thus for your mid horn to be CD it would have to be gigantic - about 8 ft. across at 250 Hz. Then this places the HF horn many wavelengths away - unless they are coaxial, which has a whole other set of problems - and there will be a great deal of polar lobing at 1.6 kHz - not CD. SO from where I sit this design is anything but CD. Unless you have data to support your contentions I will have to stick with my opinion that your hypothesis is unlikely. Mine claims, on the other hand, have substantial supporting measurements which I freely show on my web site. Sorry to disagree with you like this, but we don't see this issue eye to eye.
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Re: Favorite flavors [message #17462 is a reply to message #17461] |
Sun, 23 January 2005 20:58 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
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Wayne Parham
Messages: 18748 Registered: January 2001
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Illuminati (33rd Degree) |
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OK, Earl. Perhaps we don't see eye to eye. Or maybe there's more to it than that. There are seven π cornerhorn response measurements in the link on my last post, both on-axis and off axis. Beyond what is shown there, I don't see the need for additional measurements that prove π/2 radiation defined by a room corner. It is a radiating pattern definition, not a hypothesis or a speculation about an acoustic device. I really think it's needlessly combative to even bring this matter into question. It is easy to hear the difference in output from corner loading. It's immediately noticeable. The DI formula illustrates the fact that there is increased power due to directionality. That wouldn't be the case if the corner weren't providing directionality. As you know, the equation was written by C.T. Molloy to quantify the directivity index. I imagine the data on your website is probably specific to your speakers, and from your position here, I don't think it has anything to do with using room corners. I guess that means your arguments must be based on intellectual skepticism. Maybe it's best to limit your comments to a description of your thoughts and ideas. Or maybe you can substantiate your remarks with measurements that are relevant to this discussion. Don't hesitate to use formulas and include technical details. I'll do the same for you.
Let me ask you: - Do you believe that a horn's behavior is modified by the radiating space it is used in? Specifically, do you think a baffle mounted horn or one used in quarter-space or eighth-space can be made smaller than one used in freespace?
- Do you agree that a room corner produces 9dB DI over omnidirectional radiation?
- Since those things are accepted by most everyone in the industry, what measurements or other data might you have that suggest otherwise?
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Re: Favorite flavors [message #17464 is a reply to message #17463] |
Sun, 23 January 2005 22:23 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
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Wayne Parham
Messages: 18748 Registered: January 2001
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Illuminati (33rd Degree) |
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You're a smart guy Earl, and I think that if you have a valid argument you can probably discuss it intelligently. So I ask you again, what do you attribute the 9dB DI power increase from eighth-space radiation if it isn't from directionality? If you agree that a room's corner has DI ≈ 9, then maybe you'll consider taking advantage of that, combined with high frequency horns having DI ≈ 9 to provide constant directivity across the audio band.
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Re: Favorite flavors [message #17465 is a reply to message #17442] |
Mon, 24 January 2005 04:13 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
Rainer
Messages: 4 Registered: May 2009
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Esquire |
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"I want the power response to rise at lower frequencies in my rooms because I design them to have a lot of low frequency absorption. The increased power response at LF is exactly compensated for by the increased absorption." What about typical rooms that don't have your special absorption? Won't room gain add to abnormally boost the bass? How does that jive with "the increased power response at LF" of your speakers?
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Re: Favorite flavors [message #17468 is a reply to message #17465] |
Mon, 24 January 2005 09:14 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to previous message](/forum/theme/AudioRoundTable/images/down.png) |
Earl Geddes
Messages: 220 Registered: May 2009
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In the kind of room that you describe the bass from my speakers and any other speaker, will not sound very good. It will be boomy and resonant. I think that we are talking ideals here, not "How does one design speakers for bad rooms". And I continue to contend that it is inappropriate to talk about directivity or power response or any concept that requires thatthe space be acoustically difuse at LF (i.e. below about 200 Hz.) We ahve talked about this problem and the solution is lots of damping and several woofers. Directivity is not relavent.
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