New Lii-Audio “Fast-15” - anyone hear these yet?

[Zoran]

Finally got around to some tests today and the network that was supposed to tame the 5k peak does not seem to be doing much. Resistors were both set at the same value as the network by Steve Deckert/Decware described earlier in the thread. The plots shown here are of the right speaker with and without network and the third is of the left speaker with the network. I guess I was wrong to assume the resistance value he defined would be approximately right for my needs, although I think it should be the same value whether you're using a flea watt tube amp or a modest solid state amp like my F5. Right? I didn't drag the speakers outside to test but the mic is very close to the driver and on axis (see pic)

Thank You very much. That is one of 2 posts (from all of this 17 pages) that giving us something real.
cheers!

 

[Zoran]

Started to use REW and go for a first measurement from the right baffle.

View attachment 1172115

Thanks a lot !
One of 2 meaningful posts in these 17 pages...
Cheers

 

[GM]

I guess I was wrong to assume the resistance value he defined would be approximately right for my needs, although I think it should be the same value whether you're using a flea watt tube amp or a modest solid state amp like my F5. Right?

Not as stated since it's the total series resistance (Qts') the driver must 'feel' that must be the same, so the flea power might be a matching impedance = 8 ohms whereas the F5/whatever has much less, so would need more.

(Qts'): (Qts) + any added series resistance (Rs)

 

[Zoran]

Yes GM that should be tried too. Thanks for the link.
.
And CL circuit for "extending" bass very LF region.
First serial input C=1000-2200uF cca. and then L=15-22mH cca. parallel.
(like II order CL filter configuration)
The proper values can be simulated or calculated.
(I tried once with some M-core siemens L, very low Rdc, about 22mH...)
.
Unfortunatley that F5 is without "big" C @ output
(With amps that has Cout usage of "extending" CL circuit is not good because it will "short" total value of C in serial connection. But it could be used with parallel L because C already is present.)

 

[Zoran]

For RLC calculators serial and parallel use online to check and for starting point only.
Because they presented net out of the wider network context...
Pretty much as used...
.
https://www.circuitbread.com/toolbox/rlc-calculator (with Q factor, no damping factor)
https://ncalculators.com/electronics/rlc-circuit-frequency-calculator.htm (with DF, no Q factor)
.
present RLC net is
(DF is unitless cm is mistake...)
Center Fo is 6100Hz
BW is -3db (3236.5-6100-8963.5) Hz
(note -3db border against needed att. and more narrow BW in praxis...)

 

[Sinisterexaggerator]

Not as stated since it's the total series resistance (Qts') the driver must 'feel' that must be the same, so the flea power might be a matching impedance = 8 ohms whereas the F5/whatever has much less, so would need more.

(Qts'): (Qts) + any added series resistance (Rs)

Thanks @GM, makes sense. Here's the F5 output impedance from the owner's manual. "
The gain of the circuit is 15.15 dB. The input impedance is 101 Kohm, and the output impedance is 0.1 ohms, for a damping factor of 80."

 

[GM]

You're welcome! Surprised it's that low, same as most of the amps I've used over the decades, so can't go wrong IME , just assumed all his amps would be relatively high.

 

[Sinisterexaggerator]

So @GM, do you know the calculation to determine what range of variable resistor would be suitable for my output impedance? 50 ohms was not enough. If I ever went back to having other sources for music I might take another run at a passive network. Probably not though; there is still the high end needing a boost and I only use a digital source (Qobuz/Roon with the Muse DSP built into Roon) so the DSP solution makes rhe most sense to me. I may sell the networks I made on the swap meet if I can find a buyer. Nice parts.

 

[GM]

No clue, I'm strictly analog.

edit: FWIW, I use(d), recommend dialing in a critically damped speaker in room with a ~cheap 50 ohm pot and replace with a resistor or small resistor 'bank'/'grid', so use a larger one?

 

[Sinisterexaggerator]

Post 283 and 384 on this thread show the network, which is totally analog and only good for addressing the midrange deficiencies.

 

[Alffie]

I hope I won't need additional floor joists--it's an old house.

You DO need bigger baffles for these to work at their most.
I used them for almost two years with homemade baffles and twoRel subs.
Using the right baffles is what made them sing.The Rel's are in their boxes now.

 

[Sinisterexaggerator]

a

You DO need bigger baffles for these to work at their most.
I used them for almost two years with homemade baffles and twoRel subs.
Using the right baffles is what made them sing.The Rel's are in their boxes now.

I agree, and I would have gone for a few more inches on the sides and top if it wasn't for the hard limitation of my room size and the fact that the front door would hit the speaker when opened. I think my wife might have freaked out too. She's been quite patient with me and it's her house too.

 

[caisson rj]

F 15 and Fast 15 are totally different drivers. It's not about the bass it's also not playing in the same league. For the current product line Lii Audio has stopped producing F15. F12 remains and F18 but not F15. I am also sharing the Lii Audio recommandation cabinet for Fast 15 (this is the 2022 product).
There is chinese in the specs, because as I explained before, Lii Audio and Lii Song are 2 differents brands. The later copied the first one, as I already stated before. But to get deep in this you need to either speak chinese or travel to china (Hong Kong have some resellers).
I did not catch up with all the pages, long time i did not connect here.

 

[caisson rj]

I guess it would be this;

View attachment 1168127

See? It's red, vs green.

It's not about the color, it's about the sticker saying Lii Audio, not Lii Song.

 

[johnvb]

Those look like the ones I bought off of Amazon. Right now running them in test baffles, to determine the best height (looking like it's going to be 36"-37" off the floor to the driver center). Next step is to build larger proper baffles, and figure out how to incorporate four beta 15s for bass augmentation.

https://www.amazon.com/AVPLAY-FAST-...keywords=lii+audio&qid=1703523181&sr=8-3&th=1

https://imagizer.imageshack.com/v2/1024x768q70/922/jC7dQs.jpg

https://imagizer.imageshack.com/v2/1024x768q70/923/R1rsvO.jpg

 

[caisson rj]

Yes with the horn logo on the paper membrane, this is the real stuff. For info the horn is because it looks like a flower found in Hangzhou called morning glory (in english). So the full name in chinese could be translated like Lii Audio Xizi morning glory. Xizi is the name of the lake in Hangzhou.

I did not know that some people sell those drivers on amazon.

 

[Phloored]

Cool their on Amazon. I am intrigued by
This one . Pricy but that's a lot of alnico!
ttps://a.co/d/9Y1d17w

 

[caisson rj]

This is a smaller size than the music 10, another alnico. I did not listened to this one, but I know the founder is a fan of old alnico drivers, he collected quite a lot of them. I think he got the paper material pretty spot on, i saw some reissue of old alnico drivers from another brand and the paper cone was not on the same level as the pair i have. Light and stiff.

 

[Phloored]

That's cool. I'm going to try them at some point for surei am finishing a transmission line that is 140 let volume i will try it in.

 

[Phloored]

I think he should sub brand his drivers with the name "original trumpet flower". I sure hope he has a good customer base in China because it's a tragedy the deception that's taken place in the West with the lii audio website making people believe they are buying lii audio when they are buying the fake.