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Bertha BH-882 Build

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Young Croc
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jo bg Quote  Post ReplyReply Direct Link To This Post Posted: 08 January 2023 at 9:52am
Scaling everything will make a dfferent horn and lower the tuning. If you want to keep same tuning you have to keep same horn length and just find a way tofit bigger driver - check rear chamber too.
27 is already a low tuning, lowering it will probably lower efficency in exchange for not so useful 23hz output - unless you are going for cinema fx
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 08 January 2023 at 10:39am
Originally posted by Twintub Twintub wrote:

21"/18" = 1.1667
Multiply all dimensions by 1.1667Smile

 Very bad idea. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote BigSoundNorthWest Quote  Post ReplyReply Direct Link To This Post Posted: 08 January 2023 at 11:27am
Originally posted by Twintub Twintub wrote:

21"/18" = 1.1667
Multiply all dimensions by 1.1667Smile

Nope.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote csg Quote  Post ReplyReply Direct Link To This Post Posted: 08 January 2023 at 11:46am
Regardless of the change of scale, what exactly are you trying to achieve using 21” drivers in a box of this style?

The function of a horn is to provide a better match between the driver and the air it is trying to move. In essence a horn increases the effective size of the drivers you are using. This makes the coupling between the box and the outside world more efficient.

Bigger drivers in a horn does not automatically mean lower frequency response or more output, although this may be possible with good design. But merely scaling up or down an existing design to suit your purposes does not automatically work, there are far too many variables for that.
“The fact is this is about identifying what we do best and finding more ways of doing less of it better”
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Zitikaz Quote  Post ReplyReply Direct Link To This Post Posted: 08 January 2023 at 5:50pm
Originally posted by csg csg wrote:

Regardless of the change of scale, what exactly are you trying to achieve using 21” drivers in a box of this style?


HI

I would like to reach 25hz with good response natural bass, 21lw1400 seems suitable driver. Plan is to use Levan ext aswell
Maximum spl isnt primary goal, trying to get 25-60hz flat response.


or better look Rcf 18x401 and forget upscaling to 21"?



 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote csg Quote  Post ReplyReply Direct Link To This Post Posted: 08 January 2023 at 7:39pm
If huge SPL is not your main aim low tuned reflex would be my first choice. BMS18N862 is one option with its huge x-max.

Flat 25Hz Front loaded horns are going to be huge


Edited by csg - 08 January 2023 at 8:10pm
“The fact is this is about identifying what we do best and finding more ways of doing less of it better”
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