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Foam Core Board Speaker Enclosures?
Foam Core Board Speaker Enclosures?
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Old 1st December 2012, 02:23 AM   #181
xrk971 is offline xrk971  United States
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Foam Core Board Speaker Enclosures?
Cochleus,
You are the king of foam core projects! You like building tall waveguides, I like thin flat ones... thanks for sharing your stash of tubes.
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Old 1st December 2012, 03:19 AM   #182
Cal Weldon is offline Cal Weldon  Canada
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Foam Core Board Speaker Enclosures?
Quote:
Originally Posted by cochleus View Post
Here is a pic of some of my experiments...
I like this guy. But I don't see any in the shape of a snail.
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Old 1st December 2012, 03:49 AM   #183
cochleus is offline cochleus  United States
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Old 1st December 2012, 03:53 AM   #184
xrk971 is offline xrk971  United States
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Foam Core Board Speaker Enclosures?
That's why he should build the Cornu spiral.
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Old 1st December 2012, 03:55 AM   #185
turk 182 is offline turk 182  Canada
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Cal you just got smacked

p.s. isn't cochleus the proper name for the inner ear?
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Old 1st December 2012, 03:56 AM   #186
klampykixx is offline klampykixx  Australia
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thanks for the comments,

just thinking out loud here for a moment, if i was to make the throat chamber larger, and the horn path shorter, what would that do to the response?
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Old 1st December 2012, 03:57 AM   #187
cochleus is offline cochleus  United States
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@xrk971

well actually, the cornu has been fuel for thought...I have a "new" idea...
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Old 1st December 2012, 10:58 AM   #188
picowallspeaker is offline picowallspeaker  Italy
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@ klampykixx

I don't see the two speakers, just one big....are you going to separate them ?
I wish.
Then, looking at the mouth of the horn which partially covers the lower driver, you should try a quasi-series arrangement of the two, shunting the lower speaker with a cap. So only one of them would emit the higher frequencies, which is the higher driver
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Old 1st December 2012, 11:04 AM   #189
xrk971 is offline xrk971  United States
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Foam Core Board Speaker Enclosures?
Quote:
Originally Posted by klampykixx View Post
thanks for the comments,

just thinking out loud here for a moment, if i was to make the throat chamber larger, and the horn path shorter, what would that do to the response?
The throat, or the pre-chamber behind the drivers larger? Making it shorter pushes the tuning freq of the design higher by proportional amount. For example, if length is 73 cm and you decrease length by 7.3 cm (10%), the 114 Hz freq will rise by about 11 Hz. If your channel width was not so skinny as to be the limiting area or choke point, increasing it helps increase the efficiency of the bass output, to a point. Increasing the throat area greater than the piston area does no good. Making the actual chamber larger is a more complex effect that must be modeled using MJK's Mathcad worksheets as it adds capacitance to the acoustic impedance of the tml.
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Old 1st December 2012, 11:22 AM   #190
xrk971 is offline xrk971  United States
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Foam Core Board Speaker Enclosures?
Quote:
Originally Posted by picowallspeaker View Post
@ klampykixx

I don't see the two speakers, just one big....are you going to separate them ?
I wish.
Then, looking at the mouth of the horn which partially covers the lower driver, you should try a quasi-series arrangement of the two, shunting the lower speaker with a cap. So only one of them would emit the higher frequencies, which is the higher driver
That would solve your undersized throat problem as the throat is only needed for bass extension.
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