Subwoofer options with LG driver, measured impedance and TS params

[lene]

Hello there!

I need a sub for a small living room. Asking about recommended enclosure config, I have two possible ones to get started with.

Are those reasonable setups?
What would you pick?

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I got this driver from a wireless sub that came with a LG soundbar. I didn't use it much. It seems there are a few different drivers labeled LGZ40. It came in a ≈ 9L ported enclosure.



I measured this (attached full file).

fs 71.1 Hz
Re 3.51 ohm
Qms 7.663 Qes 1.118 Qts 0.976
Mms 37.23 g Cms 0.134 mm/N Rms 2.171 kg/s
Vas 3.91 litres Bl 7.223 Tm
Lp (1W/1m) 83.05 dB
Dd 13.50 cm Sd 143.1 cm^2

I see two configurations that look interesting.

1) Ported @ 30Hz in a 18L box. 10W.

2) 4th order. 10w.

Thanks.

 

[KaffiMann]

Looks like you have everything well in hand, I guess either would work, though I am wondering if the excursion numbers are somewhat high. Seems like you will be running this thing a little bit hard.

 

[lene]

Seems like you will be running this thing a little bit hard

Thanks for the feedback.
10W to see how it behaves 🙂 But not sure how much I'll need in real life. I guess less for the small room.

It seems it makes sense to tune it a bit higher and use less power. Same SPL and less excursion. Smaller box.
15L, 5W, tuned at 40Hz.




I have buffers, so the idea is to fill the low frequencies and have early low-pass.

 

[KaffiMann]

Looks really good to me, though personally I prefer a bit more sloping roll off because it helps with group delay a bit.
So perhaps mess with the port a little more, see if it is possible to get the FS around 30-35 like your first post, only with a soft knee instead of a hard one if you know what I am talking about.

Other than that, nice little project.

 

[lene]

I never reported I built the ported version as recommended. I had this heavy box around and I ended up using it. I didn't measure a lot, other than a quick session to set the low pass. Much better than in the original box. 🙏