For the past couple of months, I have had two of the Lii Audio W-15 bass drivers sitting in the shipping carton and have been too busy to make a baffle for them.  Curiosity finally got the better of me and I mounted one in a baffle that wasn't in use.

Wow !!!

This driver is the real deal .....



Larger photo here.

It's certainly more expensive than the Eminence Alpha drivers I offer in my bass baffles ..... but there is a reason for that.
The thing is built like a brick outhouse.
It is heavy ..... and I mean HEAVY !!!

It has dual voice coils and binding posts which provides a lot of flexibility for amplification.
I am currently powering the one in my room with an inexpensive plate amplifier (connected to the SE84UFO via the high level inputs) and summing the left and right channels to mono.

The free air resonance is 28 HZ and the .QTS is very good for open baffle.
In addition to "digging deep", the detail and harmonics this driver produces adds a new dimension to the lower bass frequencies.

I have it paired with some Lii Audio Fast-8 baffles and the combo is absolutely wonderful sounding. It works equally well with the Betsy baffles.

The part that is really mind blowing is how much it adds to the Lii F-15 baffles, which roll off around 50 HZ or so.
The W-15 digs a lot deeper than the F-15 does .....

The "bad news" is that I don't think that shipping a baffle with the driver mounted would be a good idea. The weight of the driver would probably reduce the baffle to splinters and sawdust if the shipping carton was dropped .....

So ..... I will be offering a baffle without the driver and the buyer can order the driver directly from Lii Audio. The driver opening and pre-drilled screw holes will allow the driver to be mounted in five minutes or less.

Info can be found here.

I'm sure that there will be many more DIY folks who build their own baffles rather than purchase one from me ..... but that's OK.
If a person wants to add some seriously good bass to their system, this driver is a great option.
It's about the music .....

Happy listening,
Randy

Did you try it with power to just one coil?

By connecting only one the QTS is doubled to 1.58.

Hi Lin,

Wow !!!
That's pretty crazy .....
I was not aware of that, so thanks for the heads up.
I tried connecting the plate amp to both sets of binding posts today (in parallel).
The sound was "different" at the same volume setting and I am still trying to wrap my head around the differences.
I will do some more listening over the next few days to get a better grip on what I'm hearing.

Hi Stefan,

I won't be offering any baffles larger than the ones I am currently making because my packaging (for shipping) is set up for the one size of baffle.
I'm thinking that your suggestion would produce some serious bass.

If you decide to build something like this, I would suggest buying a hernia belt before trying to move it .....

As previously mentioned, these drivers are HEAVY .....

Best wishes,
Randy

how does the Open Baffle bass compare to the small parts express subwoofer you have been using - do you notice much difference in sound quality and ability to blend with various betsies.  Lii15s here and about to start blending with a Rel 7ti.

Casey, if you can add another T7i I think you will be very happy.

How do they compare to the hawthorne augies Randy?

Might they be replacement considerations in trios with the sterlings?

Thanks John

Hey Randy,
I wonder, have you ever tried to use the closed box subwoofer together with the W-15 and just use the closed one for the really low frequencies? Or would the closed box sub not mix well with the open baffle one?

Hi Stefan,

No ..... I haven't tried that.
However, based on all of the music I have used to test the W-15 baffle (acoustic bass, electric bass, synthesized bass, pipe organ, Hammond B-3, kick drum and kettle drum), if there is bass below what the W-15 is producing, I can't tell that anything is missing.

There might be an issue with the "speed" of the bass at different frequencies with open baffle bass and box bass ..... but I can't say for sure .....

This is with the W-15 being powered by an inexpensive 100 watt plate amplifier. If a better amp is used, the potential results would probably be pretty frightening .....

Even more important to me is the quality of the bass ..... which is superb.

Best wishes,
Randy

I just completed a set of F-15 OB's based on Steve's plans. I had extra wood and built a 3rd baffle for a W-15 woofer. So now I'm trying to determine the best option for connecting the W-15 woofer. I'm not at all opposed to a separate subwoofer amp, but could I connect(shared with the F15's connection) the W-15 directly to my ZMA using one set of the binding post on the W-15 for left channel and the other set of W-15 woofer binding posts for the right channel? Will it short? I'm unsure of what the dual binding post allow? In other words could I connect a pair of cables to each channel on my amp with one cable feeding the F-15's and the second cable feeding the W-15's without knocking the earth out of orbit?  Many thanks for your input.

Randy,
Thank you for help. I have ordered a plate amp as you mentioned. I couldn't get my head around the two post speaker connections! I never got past it and didn't even think about the freq., phase etc. LOL
Merry Christmas and thanks for the help.
Malcolm

My main concern was the frequency "overlap" between the F-15 and W-15 drivers, since the W-15 goes out to 5000 HZ .....

Having said that, I have not tried it in my system.

Due to the fact that the W-15 is so much lower in efficiency / sensitivity, it's possible that the blend is more "friendly" than I would have expected ..... just guessing.

The plate amplifier will definitely provide more control ..... crossover point and volume, but if the connection directly to the main amplifier is already working well, you might end up preferring that setup .....

I learned a long time ago that it's best to "never say never" in the audio hobby and I learn something new every day .....

Happy listening,
Randy

Hello joespride,

In my listening room, it depends on which drivers I'm using in the main speakers. Since I alternate the WBAL Betsy drivers, the Lii Audio Fast-8s, the Lii Audio F-12s and the Lii Audio F-15s ..... the crossover point is different for each of them.

The range is anywhere from 60 HZ (for the larger main drivers) to 150 HZ for the smaller main drivers.
In my experience, it will also depend on the room and the placement of the W-15 baffle(s) within the room.

When I'm "dialing in" a bass baffle or powered subwoofer, I sit in the primary listening seat and have an audio buddy adjust the crossover and volume of the bass until it sounds right to me.

After that ..... I usually back the volume off slightly and that sounds the most natural to me.  

Happy listening,
Randy

Clamps are of course temporary for testing  ;)

Several of us are using a Crown XLS-1002 sub amp. You only need one, and can run two bass drivers in stereo.

The Crown is not too expensive, and works very well. Using Palomino’s ‘magic cable’ recipe works great. These are a single wire run from each input on the Crown, with a resistor soldered inline to the positive pin on a RCA plug on the Crown side, and run to each positive speaker terminal on the main amp.

The Crown has volume/crossover settings that you just adjust by ear.

Best,

Geno

One particular plate amp (280W mono) I'm looking at has wiring for two drivers, so it looks like a possibility for hooking up to the W15. This has both low and high level inputs which is great as all my amps have high level outputs only.

One question I have is would it matter which coil is wired to which output wire as one of them looks to be inverted? Does this matter or is it something to experiment with?

OK, I can see that oppositely phased inputs to to the same driver won't work, so I presume this type of design suits a sub with two drivers. In effect you would get a "push pull" effect, so doubling the sub's output and effective power. I've heard of bi-amping a speaker this way, but never heard of it done with a sub. Seeing as this is a dedicated mono sub, it seems strange. This is the amp on Ali:
https://www.aliexpress.com/item/32842731715.html

As I recall in a 'Ripol' sub, the two drivers are out of phase. >>>>Correction<<<< as it turns out, I misread what they were describing about phase. It turns out that the 'Ripol' sub acoustically puts out one phase of bass to the front of the sub while also putting out a 180 degree out of phase bass to the rear. Says nothing about the electrical connection. Just trying to find something relevant for this topic.

 

Thanks Lin, that is an option. I was also wondering why a second driver, or voice coil, could just be wired to the out of phase channel output reversed. There we go, reversing the reversal. Then Both outputs would be of the same phase.
One output, 'phase correct' to one voice coil.... then the other output, 'out of phase' to the other voice coil, BUT reversed to be 'phase correct'.

Thanks Lin, so you think the SA100 will drive them OK?

Thanks Lin. Yes, I'm in Australia, but the Dayton stuff is available though agents, although VERY expensive due to the tyranny of distance and our crazy import tariffs and taxes. I'll look around and see if I can find a deal.

I see that the SA100 is 75W into 8 ohm, but the full 100W can be achieved by connecting the W15 in parallel, so the amp would see 4 Ohm. Convenient.

I experimented a bit today. I had an old 50W sub with an 8" driver, so I pulled the plate out and connected it to the W15. It was terrible and it barely drove the W15. However, driving a nice 8" Peerless driver, it sounds great, and is plenty fast.

Next I connected a Class D mono amp that I had. It doesn't have high level inputs so I made a divider to drop it to line level. Into 4ohm the amp puts out 600W and into 8ohm, 300W. I tried both ways and it did drive the W15 to acceptable levels, but the sound of it was terrible. Definitely not HiFi!

Hi tybee,

Many thanks for the kind words .....

Your visit to my listening room was a treat for me .....

Good tunes .... good conversation ..... it doesn't get any better than that.

Happy listening,
Randy

Looking good Randy

Hi jec3504,

I don't see any reason that this would not work .....

Happy listening,
Randy

With the help of Geno, JBzen, and a couple of other generous advisors I’ve pretty much got the room holding my Elekit TU8200DX driving DIY Lii F-15 Big Betsy pair sorted. I’m not feeling like there’s a lot missing, but winter will be coming to Vermont sooner than later and I’ll need a new project or two. Besides, I’d like to see just how much sound I can wring out of this system.

I’ve been reading this and other threads but due to my lack of knowledge and experience, I have questions.

I’m leaning towards a single Big Betsy baffle matching the ones I’ve got. The plate amp Randy recommends is certainly budget-friendly and I’m wondering exactly the best way to wire it to the single Lii W-15 driver. So, can someone offer Elekit/sub amp/W-15 connection-by-connection instructions for this undertaking?

I’m also wondering how those using this setup are mounting/housing the Dayton plate amp. And if you’re using some other sub amp, what is it?

Thanks!!

Geno said:
"Using Palomino’s ‘magic cable’ recipe works great."

What is this 'magic cable' recipe you mention?

I tried a search and it brought nothing more than your post and one more older.

On one of the other threads Steve and one of his clients spoke about removing certain fail safe components like fuses from the circuit and hard soldering interconnects acknowledging improved results but cautioning the risks. I may be mistaken but I believe he said the risk was real but was less likely because of the overbuilt transformer.

I’m using a Crown XLS1002 into a single W15. Should I bridge it to mono and use one of the coil taps or run a cable from each channel into each of the voice coils? Is there any danger to the amp or speaker doing one way over the other?