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Old 5th October 2014, 07:17 PM   #1
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Default Vented/sealed sub design

In reading on the net about Dunlavy Loudspeakers, I came across a post by someone who, if I recall correctly, worked for Dunlavy at one time.
The poster mentioned that Dunlavy woofer cabinets were ducted or vented enclosures that were inside of larger sealed cabinets.

Does anyone here have an opinion as to if this is even possible?
I'm getting ready to design a large enclosure that will house a smaller vented enclosure. Using either a 12" or 15" driver.

Opinions appreciated.
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Old 5th October 2014, 07:36 PM   #2
ODougbo is offline ODougbo  United States
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Something like this?
Loudspeaker enclosure calculating with Thiele Small parameter
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Old 5th October 2014, 08:13 PM   #3
sreten is offline sreten  United Kingdom
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Hi,

Its pretty pointless inside a totally sealed cabinet.

DCR or DBR reflexes

Click the image to open in full size.

Weems or Fostex are the sort of thing used with
FR's and are in all respects pointless for subs.

rgds, sreten.
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Last edited by sreten; 5th October 2014 at 08:15 PM.
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Old 6th October 2014, 02:55 PM   #4
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Default ELIPSON - Resonator

Quote:
Originally Posted by speedygg1 View Post
In reading on the net about Dunlavy Loudspeakers, I came across a post by someone who, if I recall correctly, worked for Dunlavy at one time.
The poster mentioned that Dunlavy woofer cabinets were ducted or vented enclosures that were inside of larger sealed cabinets.

Does anyone here have an opinion as to if this is even possible?
I'm getting ready to design a large enclosure that will house a smaller vented enclosure. Using either a 12" or 15" driver.

Opinions appreciated.
What you are describing looks a lot like a frequency trap (that I doubt!) used a lot by the French, eg. Elipson.
Provide more details of the Dunlavy speaker you know.
Elipson replica
Gamme ELIPSON en 1975
Résonateur ELIPSON
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File Type: gif Helmholtz Resonator Equivalent Circuit.gif (11.2 KB, 217 views)
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Old 7th October 2014, 02:57 AM   #5
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The post I read was rather vague but I believe he was an ex employee at Dunlavy Audio Labs. It was just something simple like " the secret to the extended deep bass was a cabinet that was vented inside of a sealed cabinet".
Nothing more than that and I doubt I could find the post again.

I see from one of your links that a French company used this technique.
My French is poor so I can't translate what the papers say.

Thanks for the info.
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Old 7th October 2014, 03:16 AM   #6
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also used in RH Labs subwoofers from 70s
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Old 8th October 2014, 08:42 PM   #7
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I see by the graphs,the Resonator behaves differently with a sealed chamber vented into another sealed chamber.

Sadly, I don't read French so I cannot tell what the graphs are telling me.

Are they saying that better bass and a lower F 3 are possible with this type of enclosure?
If so, how do I work a woofers specs to determine cabinet size, etc.?

The past quote of the Dunlavy employee who stated the use of this got my interest as the minus F3 points of Dunlavy speakers are always very low.
Much lower than the numbers I get when doing the sealed box math for the woofers he used.

Dunlavy used a pair of Scanspeak 8565 10" woofers in his SCIV A.
And, Vifa M30 12" woofers in the SCV.
Both speakers tested well below the F3 points that I get on paper when doing the math for them.

Thanks for your help.
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Old 9th October 2014, 12:07 AM   #8
Zero D is offline Zero D  United Kingdom
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Inductor appears to be right about the frequency trap. Untitled Document They are intended to filter out unwanted resonances.
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Old 9th October 2014, 08:15 AM   #9
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Quote:
Originally Posted by speedygg1 View Post
In reading on the net about Dunlavy Loudspeakers, I came across a post by someone who, if I recall correctly, worked for Dunlavy at one time.
The poster mentioned that Dunlavy woofer cabinets were ducted or vented enclosures that were inside of larger sealed cabinets.
The flagship Duntech Sovereign loudspeaker used a sealed enclosure.

SOVEREIGN

Duntech states - "An optimized, sealed enclosure is used to provide accurate reproduction in preference to a vented enclosure which very often produces a woolly or ill-defined sound."
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Old 10th October 2014, 03:19 AM   #10
Zero D is offline Zero D  United Kingdom
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As David McBean pointed out, Duntech does use sealed enclosures, but the F Trap "can" be utilised in such. I didn't see any mention of them though !
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