Hello,
I've had a Focal 33S subwoofer lying around for a decade or so, and I'm gearing up to build a sub out of it. The 33S has been out of production for a long time, and it was originally intended to be a car audio sub in a recommended 50L sealed box with an F3 of 38 Hz. I'm thinking about using it in a vented configuration as a sub with fairly modestly-sized 3-way speakers.
WinISD shows that it has an F3 of 21Hz in a vented box of 5.8 cubic feet (166.4 liters) and a vent that is 8 inches (20cm) long and 4 inches (10cm) in diameter. Does that seem right? Is there any reason why this might be problematic in a vented configuration? I'm assuming the reason that it was recommended for a sealed enclosure is that sealed is the only way to fit it in a car-sized enclosure, which is not an issue for me. But if there's some other reason not to do a vented enclosure, then I'd want to know about that. For example, I don't have an impedance curve for this, so I don't know whether that's likely to be a problem with this vented box.
TS parameters:
Sd 530.93 cm2
Xmax 12mm
Fs 25.9 Hz
Qes 0.48
Qms 14.3
Qts 0.46
Vas 107.9l
Re 2.6 Ohm
Mms 139.1
Bl 11.2
1W/1m 87.8 db
Le 2.03mH
I've had a Focal 33S subwoofer lying around for a decade or so, and I'm gearing up to build a sub out of it. The 33S has been out of production for a long time, and it was originally intended to be a car audio sub in a recommended 50L sealed box with an F3 of 38 Hz. I'm thinking about using it in a vented configuration as a sub with fairly modestly-sized 3-way speakers.
WinISD shows that it has an F3 of 21Hz in a vented box of 5.8 cubic feet (166.4 liters) and a vent that is 8 inches (20cm) long and 4 inches (10cm) in diameter. Does that seem right? Is there any reason why this might be problematic in a vented configuration? I'm assuming the reason that it was recommended for a sealed enclosure is that sealed is the only way to fit it in a car-sized enclosure, which is not an issue for me. But if there's some other reason not to do a vented enclosure, then I'd want to know about that. For example, I don't have an impedance curve for this, so I don't know whether that's likely to be a problem with this vented box.
TS parameters:
Sd 530.93 cm2
Xmax 12mm
Fs 25.9 Hz
Qes 0.48
Qms 14.3
Qts 0.46
Vas 107.9l
Re 2.6 Ohm
Mms 139.1
Bl 11.2
1W/1m 87.8 db
Le 2.03mH
Good driver for a 1/4 wave.
Reflex is fine.
A >130L net gives a good reference for your sub. Look at what YonathanZ is doing for is sub & driver, having in mind that your alignment is different. What is your Fb or tuning? In your case a good reference is Vb 136 L/Fb 20-22 Hz. Consider the net volume more the space for ports, driver and bracing as extra.
http://www.diyaudio.com/forums/subw...-regarding-port-displacement-calculation.html
Reflex is fine.
A >130L net gives a good reference for your sub. Look at what YonathanZ is doing for is sub & driver, having in mind that your alignment is different. What is your Fb or tuning? In your case a good reference is Vb 136 L/Fb 20-22 Hz. Consider the net volume more the space for ports, driver and bracing as extra.
http://www.diyaudio.com/forums/subw...-regarding-port-displacement-calculation.html
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