I have a high quality 5" speaker and I know all the parameters. I have a speaker cabinet and I know the volume of the enclosure. Now... can anyone direct me to a formula or computer program that can specify the optimum port size (diameter and length) for my speaker and cabinet?? Yeah, I'm new to this 🙂
Thanks in advance!
Thanks in advance!
I personally use Transmission Line software from Leonard Audio, it can do ported enclosures as well. WinISD is a classic, and quite easy to use for a beginner.
What is the driver, and application? Ported alignment might not necessarily be the optimal, and even if so in this case there may already be proven designs - in other words, the math has been done. .
Assuming a fairly normal-sized cabinet for that driver size, 1-2" diameter, depending on how much excursion you'll be using. Length comes from the tuning frequency you want, but a 2" diameter port should avoid chuffing for the most part. Go smaller if you can't fit the bigger port in - bigger diameter = longer port.
Chris
Chris
Not to go into great detail, but the resonant freq. of the driver is 60hz and my cabinet volume is right at .55 cu. ft. (950 cu.in) I feel a ported "box" would be best for the sake of efficiency!
Doesn't really get you more efficency, just more extension at the bottom.
What are the other important specs? Fs=60,Vas? Qt?
Box vol - 15.5 litre.
dave
Compare the maximal SPL the woofer is capable of with the max output a port can do.
Hi,
Classic "flat" tuning would be at 55Hz, but I think 44Hz is much better.*
2" diameter 3.6" long gives 55Hz, 2" diameter 6.4" long gives 44Hz.
rgds, sreten.
* Vented boxes easily overload below vent tuning. IMO
optimise F-6dB rather than F-3dB with a lower tuning.
The alignment is generally room gain friendly.
Classic "flat" tuning would be at 55Hz, but I think 44Hz is much better.*
2" diameter 3.6" long gives 55Hz, 2" diameter 6.4" long gives 44Hz.
rgds, sreten.
* Vented boxes easily overload below vent tuning. IMO
optimise F-6dB rather than F-3dB with a lower tuning.
The alignment is generally room gain friendly.
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sreten, why do you like the lower frequency tunings? How does the sound quality differ from flat tuning? Thanks
Hi,
In this case you get less output above 50Hz with a softer
knee rolloff. However at 40Hz you get 5dB more output.
Basically its more like a cross between sealed and vented.
55Hz tuning :
flat to 70Hz, -1dB at 60Hz, -3dB at 52Hz, -6dB at 46 Hz, -10dB at 41Hz.
44Hz tuning :
-1dB at 110Hz, -3dB at 62.5Hz, -6dB at 42 Hz, -10dB at 35Hz.
Rolloff is almost a straight line of -3dB 100Hz down to 50Hz.
The main difference is the knee of the roll off is 50-70Hz
for 66Hz, and 40-50Hz for 44Hz. The latter sounds less
bassy but goes deeper. It will also go lower before
overloading. Conversely the former will go louder
further up before overloading, and should be used
if e.g. the speakers are filtered at 80Hz for AV,
in fact 60Hz is probably the best tuning for AV.
rgds, sreten.
A radical tuning would be 35Hz with passive low bass line
level EQ (simple CR circuit), which basically would be tuned
low enough not to overload on nearly all music low bass.
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sreten:
I'm curious and IN NEED OF HELP!
My speaker (as posted ealier) is as follows: Fs 60, Vas .41 ft.3, total Q (Qts) .44 and the cabinet, a volume of .558.
What would a 1-1/2" dia. 2 " long port tube yeald as far as f3?
Thanks,
Rev-
I'm curious and IN NEED OF HELP!
My speaker (as posted ealier) is as follows: Fs 60, Vas .41 ft.3, total Q (Qts) .44 and the cabinet, a volume of .558.
What would a 1-1/2" dia. 2 " long port tube yeald as far as f3?
Thanks,
Rev-
Thanks, that is interesting. Is there a formulaic way that you determine this type of alignment, or do you just lower the tuning while watching out for excessive group delay, or some other parameters, etc?
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