Alpair 12P

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
LeifB60

LeifB60

Member
Joined 2015
I have made box in golden ratio. 17 - 18 liter is the volume.
Inside is the high 43 cm w 27 cm d 16 cm. 1.61/ 1.0 / 0.61 ratio. The golden ratio for no resonas.
I am happy for is very clean and sound like magic.
F3 is 55 Hz .
 
Last edited:
E

Elemental

Member
Joined 2014
I too have the 12P drivers but in an open baffle design, roughly based on the OBL-15. Yes they sound like "magic" but due to my room acoustics I'm thinking of putting them in an enclosure.
Tell us more about the box you made for yours - is it sealed, ported, how much and what dampening material?
Thanks
 
LeifB60

LeifB60

Member
Joined 2015
IT is ported. I have damping inside rearside with 2-3 cm and same left right and up and down. It is wool.
Port 1. Diam 45 mm and 60 mm long.
12 p have i placed 16 cm from upside. 14 cm from left side.
The port is placed 7 cm from left side and 20 cm from upside. It is placed same side as p12. In front.
Mirror left and right speaker.
 
Last edited:
Galu

Galu

Member
Joined 2018
For those wishing to experiment with the Golden Ratio:

How to obtain the 'Golden Ratio' dimensions of a loudspeaker enclosure

1. Width (in cm) equals the cube root of the enclosure volume (in millilitres).

2. Height equals width multiplied by 1.612.

3. Depth equals width divided by 1.612.
 
K

kp93300

Member
Joined 2007
I have done a rough sketch. Is this a correct interpretation?
 

Attachments

  • IMG_20180829_122439.jpg
    IMG_20180829_122439.jpg
    770.5 KB · Views: 446
Scottmoose

Scottmoose

Member
Joined 2005
wodendesign.com
It was Thiele who was largely responsible for popularising golden ratio for speaker cabinets back in the early - mid '70s. Nominally it spreads the eigenmodes (it does not prevent their existence), but pretty much any irrational number basis can be used as an alternative. It just happens to the best known one from architecture &c. It can be applied internally or externally to a sealed or vented box. Far from being a 'magic bullet' and it doesn't generally make a massive difference unless directly compared to something very bad, but assuming you don't sacrifice something more useful simply to achieve it, it's worth doing (or using an alternative acoustic / irrational based ratio), especially for larger cabinets.
 
Last edited:
Jason Shep

Jason Shep

Member
Joined 2014
Scottmoose said:
It was Thiele who was largely responsible for popularising golden ratio for speaker cabinets back in the early - mid '70s. Nominally it spreads the eigenmodes (it does not prevent their existence), but pretty much any irrational number basis can be used as an alternative. It just happens to the best known one from architecture &c. It can be applied internally or externally to a sealed or vented box. Far from being a 'magic bullet' and it doesn't generally make a massive difference unless directly compared to something very bad, but assuming you don't sacrifice something more useful simply to achieve it, it's worth doing (or using an alternative acoustic / irrational based ratio), especially for larger cabinets.
Click to expand...

Thanks Scott,
It’s always good for a complete novice to read an explanation of these things.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom