Lii W-21 21" woofer, who will try it?

[JohnnyAudio]

This woofer is calling me... anyone else?
What kind of box for this monster? Or OB?
The imp vs freq is pretty wild.

 

[DVDdoug]

I also have a lust for big speakers!!! But an optimized box is probably huge. (With EQ/DSP you can usually get-away with a smaller box.)

What kind of box for this monster? Or OB?

Plug the Theile-Small Parameters into WinISD (or other speaker design software).

Win ISD doesn't support open baffle designs but that's usually not optimum for bass anyway.

The imp vs freq is pretty wild.

I haven't really studied a lot of impedance curves but it doesn't look that unusual to me and it will change in a box. . (Usually it's only the minimum impedance that I care about).

The low resonance frequency and low sensitivity put it in the "home" (or maybe "studio") category. Most "pro" subwoofers used live and in dance clubs have higher resonance frequency and higher sensitivity. The final designs (in a box) are usually ported designs that cut-off around 40Hz. That's a compromise that makes it easier to fill a large venue with bass you can feel in your body.

 

[JohnnyAudio]

I also have a lust for big speakers!!! But an optimized box is probably huge. (With EQ/DSP you can usually get-away with a smaller box.)


Plug the Theile-Small Parameters into WinISD (or other speaker design software).

Win ISD doesn't support open baffle designs but that's usually not optimum for bass anyway.

Maybe I could disguise the big box as a plant holder or poker table.

 

[Grotti]

Qts is over 0.8 and Vas is nearly 1000 liters....this driver is suitable for open baffle use only and it is advertised on AliExpress accordingly..... Perhaps a high pass filtered closed box design could work, but it would be huge!

 

[JohnnyAudio]

Qts is over 0.8 and Vas is nearly 1000 liters....this driver is suitable for open baffle use only and it is advertised on AliExpress accordingly..... Perhaps a high pass filtered closed box design could work, but it would be huge!

Lets put 8 or 10 of them in a dance club.

 

[Grotti]

Lets put 8 or 10 of them in a dance club.

I would prefer something like this:

Dayton Audio Ultimax UM18-22 Tieftöner kaufen

Bestellen Sie den UM18-22 online bei SoundImports ✓ Versand am selben Tag ✓ Kostenloser Versand

www.soundimports.eu

 

[JohnnyAudio]

I would prefer something like this:

Dayton Audio Ultimax UM18-22 Tieftöner kaufen

Bestellen Sie den UM18-22 online bei SoundImports ✓ Versand am selben Tag ✓ Kostenloser Versand

www.soundimports.eu

Oh my. Yes.

 

[MAB]

The impedance graph is actually quite typical. The peak is the resonance of the woofer, the right hand side is the impedance due to inductance of the voice coil (which is oddly omitted from the specs).
It could be roughly calculated from the impedance graph. It is trivial to measure. Silly to omit. Perhaps they aren't serious.

Here is a B&C 21SW152-4 21" woofer impedance. The Lii impedance trace is smoothed too much, B&C is showing a more detailed view.

Equivalent volume (VAS) of the Lii is very large (914 liters!)
Power handling of the Lii is quite low. Certainly not a dance club sub. Also would not be a good candidate for a small box with DSP alignment.
Lii claims it is optimized for open baffle. Uh, I'll hold my comments on that.
Should model it and prove to yourself what it is capable of, and what it's limitations are, but Lii typically omits key parameters for reasons I can't understand. I do wonder if they are serious. I tend to think not, but I have never worked with any of their drivers. They make some really expensive and really silly looking fullrangers, which is also a red flag for me.
These 21" have a nice look from the picture. But I rarely see the cones of my subs.

 

[DVDdoug]

If we get past the emotional and visual appeal, two 15-inch drivers have about the same piston area as one 21-inch. There are a lot more 15 (or 18) inch speakers to choose from so there are more design options.

I actually have pair of 15-inch DIY subs in rather-large ported boxes.