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In the Forum: Horn-Loaded Speakers
In the Thread: Problems with horns: upper bass
Post Subject: The Erick’s cheating upbass hornPosted by Romy the Cat on: 5/22/2006
 skushino wrote: |
• total horn length (incl. back chamber) shall not exceed 1,00m
• the horn shall have conical approximation of a hyperbolic flare contur with m=0.6
• the horn shall have a 5/16 mouth size of a free space horn
• the horn shall have a 1:1.6 mouth ratio to minimize mouth reflections
• the horn shall not be folded to reach 500Hz upper xover frequency
• the horn shall use an EV EVM15L |
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Well, if people threw the comments “the horn shall” then they should provide reasons for it. Perhaps the guy does have his reasons. I believe I know some of them and I do not agree with his reasons, not to mention that some of his reasons are absolutely laughable.
| skushino wrote: |
These horns are an alternative to my 150Hz Tractrix. They are 77Hz, 3/16 mouth front horns with a conical shape. This is because the simulated difference to initially designed hyperbolic m=0.6 horn seem to be negligible. The horns are built from 40mm MDF. So the horn shell is pretty stiff even without a surrounding box. The driver is an EVM15L. |
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No surprise he posted at AA: those morns swallow everything! Kill me but I do not see in this horn 77Hz, horn loaded. A 15” EVM15L has primary resonance of 40Hz, with this back chamber he might jack it up a little. Why the back chamber has such a huge volume (at least external) only God knows. If he runs Fs of this horn under the 77Hz then he screw his horn overloading the mouth with LF. To increase the Fs via back chamber from 40Hz to 75-80Hz he would need superbly small space behind the driver. In fact so small that it would make the driver too “stiff” and convert this horn in the acoustic suspension arrangement with attached horn. The only explanation would be if he uses in his horn an oversized throat: I would say 8-9 inches (considering the length of the horn). This would explain absolutely anything including how he was able to get 77Hz form this size mouth. I do not know the dimensions of this thing but if to pretend the MF driver sits at it default highs then this upper bass horn has a mouth of approximately 35”x20”. This thing, considering the 8”” throat is loaded as horn down 150Hz no more. All the rest the EVM15L driver shots through the horn like a direct radiator. This was the reasons why he need to make this huge back chamber because he needs a lot of exertion form this driver, actual he might wide open it with the same result.
I visited Erick site before and I believe his site is for years in the bookmarks of my site. I like him but it does not make his new upperbass horn to comply with my views of what good upper bass horns might be.
Rgs,
Romy the caT
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