Hello,
As I'm aware the golden ratio is 1/10. If I have two holes per driver the max area of port should be divided by 2? If SD of driver is 213.8cm2 then for two holes each should be around 10.69cm2?
Max
As I'm aware the golden ratio is 1/10. If I have two holes per driver the max area of port should be divided by 2? If SD of driver is 213.8cm2 then for two holes each should be around 10.69cm2?
Max
The single flared port area should be as close to Sd as possible, and its length to diameter ratio should not exceed 3:1.
The way that I arrived at a 10:1 diaphragm area / port area is by the following figure from Harry Olson's Elements of Acoustic Engineering (2nd Ed.):
Assuming copper voice coils (multiply the square of the driver's area by 0.5), the yellow highlighted region of the graph gives one the impression of the amount of efficiency loss as a consequence of the compression ratio. While I do not know the mass of the voice coils in the woofers that I used for the K-402-MEH (Crites 1526C), I do have a figure for the Mms of the diaphragm (75.5 grams). Assuming the voice coils are ~1/10th of the Mms (which includes the cone, dust cap, former, epoxy resin, and a small portion of the surround mass), you can see that the efficiency of the system is likely still high.
I also looked carefully at the ports sizes of the Danley Unity and Synergy horns, and found that the diaphragm area to port area compression ratio to be between 5 and 10.
To answer your question: yes.
Chris
Assuming copper voice coils (multiply the square of the driver's area by 0.5), the yellow highlighted region of the graph gives one the impression of the amount of efficiency loss as a consequence of the compression ratio. While I do not know the mass of the voice coils in the woofers that I used for the K-402-MEH (Crites 1526C), I do have a figure for the Mms of the diaphragm (75.5 grams). Assuming the voice coils are ~1/10th of the Mms (which includes the cone, dust cap, former, epoxy resin, and a small portion of the surround mass), you can see that the efficiency of the system is likely still high.
I also looked carefully at the ports sizes of the Danley Unity and Synergy horns, and found that the diaphragm area to port area compression ratio to be between 5 and 10.
To answer your question: yes.
Chris
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