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Multi-Way Conventional loudspeakers with crossovers

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Old 14th August 2007, 06:22 PM   #1
Tyimo is offline Tyimo  Hungary
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Default BBC LS S/5 loudspeaker

Hi!

Could some body tell me where can I find detailed infos about the attached loudspeaker??? (sorry for the bad quality picture)
I am most interested for this "diffusor" panel.

Tyimo
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Old 14th August 2007, 07:03 PM   #2
Geoff is offline Geoff  United Kingdom
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Have a look at the following BBC document for the LS5/8 which uses a similar principle:

http://downloads.bbc.co.uk/rd/pubs/reports/1979-22.pdf

I cannot remember if it covers the design of the front panel cut-out for the bass unit.
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Old 14th August 2007, 08:14 PM   #3
Salas is offline Salas  Greece
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It widens the midrange dispersion of the 300mm woofer. Its the same principle as with slot tweeters.
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Old 15th August 2007, 06:33 AM   #4
Tyimo is offline Tyimo  Hungary
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Hi!

Thanks!

About the slots: if the slots opening is smaler than the out coming sound wave, than will be a kind of spatial sound?

Tyimo
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Old 15th August 2007, 09:37 AM   #5
sreten is offline sreten  United Kingdom
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Hi,

As alluded to in that article, if you make the slot too narrow you
will effectively turn it into the front chamber of a bandpass cabinet.

Which is not what you want .........

Also remember to leave enough clearance for the units max excursion.

/sreten.
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Old 15th August 2007, 10:20 AM   #6
Tyimo is offline Tyimo  Hungary
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Yes.

Thanks.
What could be the min. slot for an 6.5" (18cm) driver?
13cm =2600Hz?

Tyimo
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Old 15th August 2007, 11:14 AM   #7
Salas is offline Salas  Greece
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It can't be accurately decided by wave formulas alone. It takes experimentation and measurements for individual transducers. There are many things to balance. One is the off axis behavior of each 6.5'', since the dispersion is dependable on its cone flex and phase plug or dust cup. Then, the cavity behind the slot interacts with the cone shape and movement. The material and thickness of the slot baffle contributes also. Crossover frequency and slope is essential too. The goal is to get better off axis integration and certain desired dispersion without extra cavity and mechanical resonances coloring the area. In pro speakers that many such tricks are used, much wood is cut and many measurements are taken. Subjective evaluation and trial on error, is the order of the day despite the theory. I would try your 130mm starting point, it sounds logical.
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Old 15th August 2007, 01:04 PM   #8
Tyimo is offline Tyimo  Hungary
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Thanks!

I will try it soon.

Tyimo
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Old 15th August 2007, 09:42 PM   #9
ente is offline ente  Germany
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Default LS3-5a

.. maybe this helps to find something more


http://home.wanadoo.nl/dezaire/LS3-5a/LS3-5a_clone.htm


Regards
Heinrich
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Old 16th August 2007, 09:27 AM   #10
Tyimo is offline Tyimo  Hungary
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Thanks Heinrich!!!

Very good links!

Greets:

Tyimo
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