Lii Audio F18 +++++?

Hi!
The Lii Audio F18s just arrived at my place. But I have a few questions.

This is an open baffle design.
Should I add another Driver to complement the F18?
I have an Eminence Alpha15A , can the woffer be smaller than a wideband speaker?
I also have a Lii Fast8 and F12can I use it?

Gretz
 
Usually i think fullrangers the other way arround --> everything but lows (crossed with sub below 80-250Hz). But in this case such low Fs and xmax (excpetuating they will be in a big room) its the other way. U ll even have some extra gain arround Fs due to the high Qts (the cone is not that well controlled). The company doesnt put any off axis response so its just guessing... i wanst able to find any in the web either. I found this: https://www.audiocircle.com/index.php?topic=174135.0 . Apparently there are some "old" ones and some "new" ones. There are the Thielle Small parameter to play a little, Basta! may also help u take baffle step into account.
There seems to be an apparent dip arround 400 Hz and an augmentation above 1.5kHz. You may solve that with dsp (i use EQapo and Rephase). Anyway above 12Khz things may get crazy.
U may be playing safe putting a real good tranducer for 8-20Khz. At least the crossover would be far from the 3KHz. There would be a problem since transducer distancce will be signifficant to crossover frecuency, and so signals from both transducers would reach you off phase, so maybe one would aim for a high order filter, or abandon the idea altogether. One may choose to limit 18' high frecuency from 1 or 2kHz (which is more than 6 octaves, which is already a lot for a single unit). Considering cone breakup and such a big mass moving at high frequency this may be the wiser constraint.
For starters u could make them and measure them and decide upon that... Anything that would be added later to it, will be, added.

"can the woffer be smaller than a wideband speaker?"
That quote i don't understand.

Regards!
 
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The woofer can be smaller, you will have to adjust levels anyway. As long as it does not have to work outside of its acceptable performance range. If it has to work so hard that it starts to distort noticeably, it is too small.

But I would try without the woofer first. 18 inches is a lot, even for a fullrange driver on a baffle.
 
Usually i think fullrangers the other way arround --> everything but lows (crossed with sub below 80-250Hz). But in this case such low Fs and xmax (excpetuating they will be in a big room) its the other way. U ll even have some extra gain arround Fs due to the high Qts (the cone is not that well controlled). The company doesnt put any off axis response so its just guessing... i wanst able to find any in the web either. I found this: https://www.audiocircle.com/index.php?topic=174135.0 . Apparently there are some "old" ones and some "new" ones. There are the Thielle Small parameter to play a little, Basta! may also help u take baffle step into account.
There seems to be an apparent dip arround 400 Hz and an augmentation above 1.5kHz. You may solve that with dsp (i use EQapo and Rephase). Anyway above 12Khz things may get crazy.
U may be playing safe putting a real good tranducer for 8-20Khz. At least the crossover would be far from the 3KHz. There would be a problem since transducer distancce will be signifficant to crossover frecuency, and so signals from both transducers would reach you off phase, so maybe one would aim for a high order filter, or abandon the idea altogether. One may choose to limit 18' high frecuency from 1 or 2kHz (which is more than 6 octaves, which is already a lot for a single unit). Considering cone breakup and such a big mass moving at high frequency this may be the wiser constraint.
For starters u could make them and measure them and decide upon that... Anything that would be added later to it, will be, added.

"can the woffer be smaller than a wideband speaker?"
That quote i don't understand.

Regards!

"can the woffer be smaller than a wideband speaker?"

Eminence Alpha 15'' -- Lii F18''

Eminence is smaller than Lii, doesn't it matter that he's only 15 inches compared to 18?
 
I think usually one doesn't overlap different drivers responses, at least:
Both drivers are the same, so u get an idea of how the sum will be (u also get LF boost),
Or they only overlap in LF where we are pretty deaf and phase problems are more forgiving, just to get enough below 200 Hz depending on room.
Whats for sure (i think, lol) is that both woofers shouldn't be playing high enough to make the distance among centers comparable to frequency wavelength. For example a distance of 45Cm between drivers centers is about 1/4 lamda of 200 Hz, and this is as far as i would overlap them. Of course then you would be using a fullrange as a regular lF unit xD
 
I wanted to add that that thing about driver distance is correlated with the distance of the listener. Phase effects from diference of time of arrival from drivers may be more forgiving far away from the speakers.
And about off axis response i guess u already know about conebreakup and how the response will have a lobular shape. But if u hear the OB rather on axis, and thats the only response u are worrying about, with some DSP (REPHASE for example, or a minidsp), u may use it as a real fullranger. You may attenuate the odd reflections in the room above cone breakup with absorption, and hear it rather closely to keep relation of reberverated and direct soundfields low enough. A rather big room may help here too.
 
Just get some 19mm MDF, cut to 1.0 meters wide, 1,7 meters tall....mount the driver offset 0.618 on the vertical & horizontal axis...lean in up against the wall & enjoy.

-----------------------------------------------------------------------------------------------------------------------------------------------------------Rick...
 
I now have these F18 in use in an open baffle. After initially starting with the F18 alone (thought they sounded like cardboard, wanted to sell them again) they did start to break in and I started to get more enthusiastic. Then bought a set of W15 with them and built a final version. Found the highs and lows lacking, and added super tweeters. All this is now driven by two Rotel rb-980bx and a MiniDSP. I still want to delve a bit deeper into adjusting this.

First test..........,
Testopstelling W-15 F-18.png
 

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