All Eminence OB

[Pano]

I know that 60uf is a bit little..

Actually, I was thinking the opposite. 60µF seems large to me.

I'm using about 17µF on my Hemp FR8c to mate with open baffle 15" Have not yet found the perfect value, but it's somewhere near there. Maybe as much as 25µF

That nominally puts the high pass at ~1150, but with the baffle step, impedance curves and woofer added in, the cross is more like 900Hz, though the overlap is large. Since these are 1st order filters, the drivers still contribute a lot beyond the x-over point.


But whatever works in your rig is what you should use, for sure!

 

[chakija]

12Pw3 instead of Beta...

Here are mine OB-s.This is still trial version ,but my first impressions are more than great!I think first problem that needs to be solved is bass...single 12pw3 in my aspect does not provide enough low bass ,but it plays well what is able to tho ,considering it's Fs...Tweeter is selenium ST324 ,and i am quite happy what it sounds like-crisp and wide ,with airy sound.Other impressions are pretty same like previous ,Yunick-s and hakunin-s.X-over is 2.2uF & 8,5 db L-pad on ST324 ,FR Alpha ,~8.2 mH on 12pw3...

 

[chakija]

...

And reality image 😀 ...

 

[hakunin]

Nice🙂 I see you placed it near corner to gett some extra bass!

 

[adason]

hi chakija,
is there a reason why you put tweeter so far apart from midrange?
ed

 

[Zen Mod]

hi chakija,
is there a reason why you put tweeter so far apart from midrange?
ed

youth ...............

 

[Vix]

Re: ...

And reality image 😀 ...

Nice! Hope you'll like them. You'll like some things, but others (bass) may drive you crazy. Imho. It can be a pain in the a** to get them to work properly.

Do you pull them out from the back wall during listening? Looks they are too close to the back wall...

Regards,

Vix

 

[chakija]

youth ...............

that's right...
i did not realize problem till i was in my listening chair.Now i have to put 2 pillow's under my butt to get the high's right
Either i'll buy taller chair ,or i'll route hole 5 cm lower and try to seal rest of opening 🙁 (or sit on pillows 😀 )

 

[chakija]

Re: Re: ...

Nice! Hope you'll like them. You'll like some things, but others (bass) may drive you crazy. Imho. It can be a pain in the a** to get them to work properly.

Do you pull them out from the back wall during listening? Looks they are too close to the back wall...

Regards,

Vix

Well ,so far i like them very much !Mids and highs (ofc with pillows) r geat ,but bass lacks and i hope that alpha 15" fill fix it.However ,it will be difficult get them right with passive crossover...]
Baffle is about 70cm away from rear wall during listening...my room space (about 17 m^2 ) just do not let me put them any further.

 

[Zen Mod]

that's right...
i did not realize problem till i was in my listening chair.Now i have to put 2 pillow's under my butt to get the high's right
Either i'll buy taller chair ,or i'll route hole 5 cm lower and try to seal rest of opening 🙁 (or sit on pillows 😀 )

that's not just problem you solve with pillows.......

bigger problem is phase blending between 6" and Tweet .... they must be as close you can get them

cut another hole ;

use old cutout piece to glue it back to place ;

make mix of wood glue and wood particles

 

[chakija]

i'm already on it!

 

[chakija]

beta 1.2...

Drilled another hole...Man this look really ugly now !Hope i'll finish them soon enough , as they r now bringing some serious feng-shui annoyance to my room .Sound ,became lot harsher with moved tweet and just 2.2uF i thik.Now i need to experiment with lower values and i am planning to try 1uF and 1.5uF.65uF on alpha is still missing but i hope i'll put it this week.
Bass lacking is more and more irritating to my ears ,and first rave with sound is slowly fading away 🙁.It just feels kinda to stiff ... Hope it will get better with finalized crossover&alpha 15"
Oh ,forgot to mention that my source is X222ES ,and amp is Trends audio 10.1 (probably a reason more of low bass extension...)

 

[chakija]

...

...

 

[Vix]

Re: beta 1.2...

Bass lacking is more and more irritating to my ears ,and first rave with sound is slowly fading away 🙁.It just feels kinda to stiff ... Hope it will get better with finalized crossover&alpha 15"
Oh ,forgot to mention that my source is X222ES ,and amp is Trends audio 10.1 (probably a reason more of low bass extension...)

Hi,

I know the feeling....

Bass speaker definitely needs a stronger amp. Then some things may improve...

I am still in love/hate relationship with my OB's....

Will write about it in another thread....

 

[adason]

do not give up
the problem with bass might be solved by compromise
that is if you are willing to make the compromise
i believe open baffle gives greatest benefits to midrange
it brings clarity, openness, lack of boxiness
can be easily heard
but bass is problematic, while it theoreticaly should be better than normal boxed woofer, it is not for obvious reasons
for baffle is too small, cancelation is significant, woofer cone area and excursion is not enough, efficiency lower than rest...
so what is the way out? compromise! make it box for woofer, open baffle for midrange....many diy went this way and are happy
and many commercial speaker makers too
ed

 

[adason]

check out lampizators speaker projects
http://www.lampizator.eu/SPEAKERS/Loudspeakers.html
ed

 

[adason]

or Nao speakers
http://www.geocities.com/kreskovs/John1.html
ed

 

[tinitus]

Or mid/tweet needs more attenuation

 

[adason]

or woofer its own amp (biamp it!)

 

[chakija]

compromise...

Well ,i wanted to stay with original idea of simplicity and with proper drivers.If you were referring to 12" woofer ,i must say that i did not purchase it 4 this project ,but it was in stack from my previous one.It just seemed like it would be nice to try it out in this setup(Qts=0.69 ,but Fs=50 and Xmax=1.25).I have already draw a baffle cutout for 15" woofer.I decided to spend my money on 15"Alpha ,and if i would not like how it sounds ,i will sell all stack and buy some cheap Jamo-s !!!