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Beyma 12CXA400fe coaxial. Enclosure build

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Category: Plans
Forum Name: New Projects Forum
Forum Description: Forum for new speakerplans projects, in memory of Tony Wilkes, 1953 - 2014
URL: https://forum.speakerplans.com/forum_posts.asp?TID=109016
Printed Date: 26 March 2026 at 6:55pm
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Topic: Beyma 12CXA400fe coaxial. Enclosure build
Posted By: doller
Subject: Beyma 12CXA400fe coaxial. Enclosure build
Date Posted: 02 April 2025 at 7:24am
m



Replies:
Posted By: DMorison
Date Posted: 02 April 2025 at 1:53pm
Thanks for sharing that, looks like an interesting project.
I'm a bit confused about the graph though, the dB axis looks to be scaled all wrong.


Posted By: doller
Date Posted: 02 April 2025 at 2:23pm
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Posted By: fatfreddiescat
Date Posted: 02 April 2025 at 4:01pm
Try using the measurement option instead of RTA, with a scale of 20Hz-20KHz log X axis, and a 50dB between min and max Y axis Thumbs Up


Posted By: Line Array
Date Posted: 02 April 2025 at 10:34pm
i like the radiused baffle !

perhaps you missed an opportunity to use flared vents on the bottom side of the enclosure with the flare shape matching enclosure shape 

i would have put three off them in there - one in each corner - would look sick !


Posted By: doller
Date Posted: 02 April 2025 at 11:51pm
Thank you, Freddi


Posted By: DMorison
Date Posted: 03 April 2025 at 2:15pm
Originally posted by doller doller wrote:

Elaborate please. REW updated and now I am seeing red then white for the rta.
Any input appreciated.

Your use of a 400+ dB vertical axis is almost certainly obscuring a lot of detail.
As fatfreddiescat says, adjusting to about 50dB vertical range will make it more useful.
HTH,
David.


Posted By: doller
Date Posted: 03 April 2025 at 11:56pm
I have removed the offending 


Posted By: Line Array
Date Posted: 04 April 2025 at 12:04am
Originally posted by DMorison DMorison wrote:

Your use of a 400+ dB vertical axis is almost certainly obscuring a lot of detail.

that reminds of the strange vertical scale used by Beyma in their charts.  they seem to use 5 divisions per 20 db so like what - 4 decibels per division ?  what's up with that ?

Beyma is a very bipolar company IMO - they make some amazing things but they also have a lot of head scratchers like that.

i guess their logic is you shouldn't trust published specs anyway - you should order samples and measure them yourself.  but still the 4 db per division upsets my OCD.

as for 400 db vertical scale yeah the atmosphere can only support 192 decibels so it seems a bit excessive LOL


Posted By: doller
Date Posted: 04 April 2025 at 7:06am
How did we get to beyma being bipolar as a company? All I did was made some speaker boxes.


Posted By: DMorison
Date Posted: 04 April 2025 at 1:52pm
Originally posted by doller doller wrote:

I have removed the offending 

Nothing was  offensive, IMO, indeed I thought they were good looking speakers.

I was only trying to encourage you to show a little of the info about them in a little bit more detail, to make that info more useful.

All the best,
D.


Posted By: Line Array
Date Posted: 04 April 2025 at 4:02pm
Originally posted by DMorison DMorison wrote:

I thought they were good looking speakers.

me too.  i thought the shape was cool and the ceiling mount was nice too.

didn't like the ports though.

sometimes a straight port with no flare is OK and this depends on box tuning and what frequencies are fed into the box.  

so with subs for example we can use long ports without exciting port resonances and that allows us to use wide enough ports that we don't need flare.

with tops that are meant to work with subs we can tune to a high frequency and that allows us to use short, wide ports that again doesn't cause issues.

but if you're in a difficult situation where you need to tune low but at the same time you will be feeding frequencies way above subwoofer into the box you risk coloring the sound with port resonances and to avoid this you will want to make the port shorter and therefore narrower which will push air speed up at which point you will likely want to add flare to the ports ( if round ) or if rectangular then have a variable cross section to the port that is narrower in the center and wider at the edges ...

with this particular enclosure shape it would be impossible to put flared ports on the back because it wouldn't mate to the non-flat surface, but it was still possible to put them on the bottom, which is what i suggested for any possible future iteration of this design.

and i love Beyma and i'm bipolar myself - my point is simply that Beyma is all over the map from leading the industry with drivers like TPL to knocking off obsolete JBL designs with their bullet tweeters to again leading the industry with technologies like MaltCross to again making ostentatious car-audio-centric woofers with carbon fiber cones etc.  you never know what to expect from Beyma

by contrast with B&C you can always expect a boring but functional product.

the way it was explained to me on another forum is that B&C basically owns the Prosound market in Europe while other companies like Beyma, Faital, 18 Sound etc. must look for openings / opportunities to create something unique in some Niche B&C hasn't occupied yet, which is why they often come out with interesting but also strange products while B&C products always make sense but are rarely exciting.



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