Port size help

[tsenfw 10+ year member]

Ok, I have a 8" JL 8w3v2 that I'm bumpin till my 12 comes in the mail (also for testing purposes). I have it mounted in .77cu ft enclosure after sub displacement and it's obviously wayyyyyyy over the recommended .375 sealed enclosure size. The recommended ported size is .75cu ft.

If I wanted to add port(s) to this enclosure to tune it to 30hz what diameter and length pvc could I use? I couldn't find the correct answer with winisd, I was getting some really screwy results like 145" length!

I know it's ghetto, I just want some bass in the mean time and see what this 8 can do!

Sub specs:

# Size : 8"

# Free Air Resonance (Fs) : 34.5Hz

# Electrical "Q" (Qes) : 0.468

# Mechanical "Q" (Qms) : 7.84

# Total Speaker "Q" (Qts) : 0.441

# Equivalent Compliance (Vas) : 0.79 cu. ft. / 22.4 liters

# One-Way, Linear Excursion (Xmax) : 0.39" / 9.9mm

# Reference Efficiency (no) : 0.189%

# Efficiency (1W/1m) : 85.0dB SPL

# Effective Piston Area (Sd) : 33.2 sq.in. / 0.0214 sq.m.

# DC Resistance (Re) : 6.70-Ohms

# Nominal Impedance (Znom) : DUAL 4-Ohms

# Power Handling (Continious) : 125 Watts

# Mounting Depth : 4.31" (109mm)

# Approximate Weight : 8.3 LBS

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[tsenfw 10+ year member]

bump

 

[Trixter 10+ year member]

a 2" round port thats 11" long will do it for you....

ideally you would want more port area than that, but since you have such a small box, the port would end up being so long......even a 3" port would end up being almost 30" long.