The Eminence Beta CX-10 . What have you done with it lately ?

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revboden

revboden

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Joined 2011
saurama said:
Yes, you need almost 100 litres for ported box with 12CX. But! It works nicely in 50-60ltr sealed... I have three such versions (45 litres actually, very full of wool) behind my acoustically transparent screen at the moment. No, they don't go extremely low but neither does 10CX in same size ported either.

An outdoor ground plane measurement attached (the variation in lowest octave are because of the wind). Green curve is 12CX in 100ltr reflex tuned to about 40Hz, Blue 12CX in same box and reflex ports plugged (so not really closed but close...) and ugly yellow 10CX in 50ltr reflex tuned to 50Hz.


If you pack the 12CX to sealed 50-60ltr you get quite same bass as the 10CX in reflex but with 12CX's better midrange, directivity to lower frequency and sealed enclosures better impulse response.
Click to expand...

The reasion I wanted to go ported is for the reduced cone movement at low frequencys. I also like the upper mid-bass punch that 10" drivers give. Have used EAW quad 10's quite often doing special effects for Theatre productions. 12" drivers don't give the same tactile feel for some reason.

You make some very good points.

I'm going to have to buy both now and test this...

Thanks :D

Now back to learning XO design. After using only active XO's for the last 24 years this is like a petrol engine mechanic learning how to build a steam engine.
 
D

dumptruck

Member
Joined 2010
revboden said:
The reasion I wanted to go ported is for the reduced cone movement at low frequencys.
Click to expand...
Here's a sim in 55 liters @ 25W:
white = 10CX tuned 35Hz
grey = 10CX tuned 55Hz
yellow = 12CX sealed w/ heavy fill
 

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revboden

revboden

Member
Joined 2011
dumptruck said:
Here's a sim in 55 liters @ 25W:
white = 10CX tuned 35Hz
grey = 10CX tuned 55Hz
yellow = 12CX sealed w/ heavy fill
Click to expand...

Thanks, I've got the same sims using the same program actually :D I'm waiting for my replacement test leads to come in from Parts Express so I can measure the actual drivers in test enclosures... should be here on Nov 7.

I swear that waiting for DIY parts occurs in dog years. Gaaahhhhh!!!!
 
revboden

revboden

Member
Joined 2011
saurama said:
you get quite same bass as the 10CX in reflex but with 12CX's better midrange, directivity to lower frequency and sealed enclosures better impulse response.
Click to expand...

You wouldn't happen to have in box FRD and ZMA files for the drivers you used? :eek:

I am practising using XSim so when my test leads get here I'll be more experienced with the program.
 
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M

Michael Chua

Member
Joined 2006
ampslab.com
saurama said:
An outdoor ground plane measurement attached (the variation in lowest octave are because of the wind). Green curve is 12CX in 100ltr reflex tuned to about 40Hz, Blue 12CX in same box and reflex ports plugged (so not really closed but close...) and ugly yellow 10CX in 50ltr reflex tuned to 50Hz.
Click to expand...

Why are you getting a deep notch at 550Hz with both 10CX and 12CX?

The notch is not there with Eminence plot of the the 10CX.
 

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S

saurama

Member
Joined 2008
Michael Chua said:
Why are you getting a deep notch at 550Hz with both 10CX and 12CX?

The notch is not there with Eminence plot of the the 10CX.
Click to expand...

These are ground plane measurements and the notch is a reflection from ground (about 2m mic distance and 17-19cm from woofers midpoint to ground). These measurements were only to look the bass (below 200Hz or so...). So it is not a backwall reflection. 12-inchers prototype was 50cm deep, by the way :) .
 
revboden

revboden

Member
Joined 2011
saurama said:
These are ground plane measurements and the notch is a reflection from ground (about 2m mic distance and 17-19cm from woofers midpoint to ground). These measurements were only to look the bass (below 200Hz or so...). So it is not a backwall reflection. 12-inchers prototype was 50cm deep, by the way :) .
Click to expand...

What you are describing is not a ground plane measurement. A ground plane measurement would have the microphone laying on the ground.
 
S

saurama

Member
Joined 2008
revboden said:
What you are describing is not a ground plane measurement. A ground plane measurement would have the microphone laying on the ground.
Click to expand...

Sorry, of course the mic was laying on the ground. My bad... English is not my native language and seems like thinking and writing at the same time was too hard :) .

Anyway, that notch is a reflection from surroundings. I don't have a totally even surface, only grassy back yard of my "tool shed".
 
revboden

revboden

Member
Joined 2011
saurama said:
Sorry, of course the mic was laying on the ground. My bad... English is not my native language and seems like thinking and writing at the same time was too hard :) .

Anyway, that notch is a reflection from surroundings. I don't have a totally even surface, only grassy back yard of my "tool shed".
Click to expand...

I understand. I don't English so well myself. French Creole is my first language if you can call it a language :D;)
 
Pano

Pano

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Joined 2004
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It's not all that ugly. It looks like th cone had a major breakup around 2.6K. That's going to be hard on the ears, especially since you can't get out of the come much lower than that. The horn won't let you.

You may need a trap on the cone.
 
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