Swan HiVi BG5N Project

[NotBlight]

Hello!


I have been experimenting with the following speaker, making several enclosures. My goal is to make a proper vented enclosure, and tune it slightly lower than the Fs of the speaker itself. The enclosure is 10.9 lts, vent diameter is 4 cm, this is the speaker's technical sheet:
Nominal Impedance (Z)(Ω) : 8
Resonance Frequency (Fs)(Hz) : 60
Nominal Power Handling (Pnom)(W) : 35
Sensitivity (2.83v/1m)(dB) : 88
Weight (M)(Kg) : 1.5
VC Diameter (mm) : 25 SV
DC (Re)(Ω) : 6.5
VC Length (H)(mm) : 10.0
VC Former : Kapton
VC Layers : 2
Magnet System : Shielded Ferrite
Force Factor (BL)(N/A) : 7.4
Gap Height (He)(mm) : 5.0
Linear Excursion (Xmax)(mm) : 2.5
Suspension Compliance (Cms)(uM/N) : 730
Mechanical Q (Qms) : 1.71
Electrical Q (Qes) : 0.41
Total Q (Qts) : 0.33
Moving Mass (Mms)(g) : 9.8
Effective Piston Area (Sd)(m2) : 0.0079
Equivalent Air Volume (Vas)(L) : 7.1
Cabinet Type : Vented
Recommended Box Volume(Vb)(L) : 6
Tuning Frequency(Fb)(Hz) : 55
-3dB Cut-Off Frequency(F3)(Hz) : 65



Is it even possible to tune this below the resonant frequency, and how?


Thanks in advance.

 

[NotBlight]

Thank you for your help, I was able to make the sub myself. The proper box has roughly 5.6 lts gross volume, with a 32 mm wide pipe for the vent, about 35 cm long - tuning at rougly 53 Hz (67 Hz peal\k for the woofer and 35 Hz peak for the vent).

 

[GM]

Greets!

Missed this first time around.............. Since you've done it you know you can at a huge expense in power handling; for future reference though, it's a good plan to limit tuning to < 1/2 octave [0.707x] below Fs and use some form of hi-pass ['rumble'] filter.

Note that specs are a bit off based on its BL, Cms specs, though with your extreme alignment it's moot.

FWIW for any others searching for help with this driver: with such low power handling [2.5 mm Xmax], the pioneer's [classic] reflex, [Vb] = Vas/1.44, Fb = tuned to actual Fs, maximizes power handling Vs size, tuning, though of course not the flattest response.

Regardless, what's the app and does it perform well, i.e. satisfied with it?

Now I can say you're welcome! 😉

GM

 

[NotBlight]

Thank you for your advice. I decided to disassemble the speaker one last time in order to shorten the vent. Frequencies under 60 Hz were severely diminished with no improvements in power handling in low frequencies. I actually ended up increasing the vent length by another 10 cm, and I am happy with it - this has actually improved the sound a bit as the vent peak is nearing 30-35 hertz, which are the exact frequencies which cause clipping (or underpowered clipping as my amp is a small 20W one), and the speaker's motion is slighly limited in that bandwidth.