DIY OB Project using the Lii Audio F6 Full Range

[CJP]

This thread is to help document the OB project that was started off a while ago as part of a WhatsApp group. Thanks to @yogibear , who is the friend, philosopher and guide of the OB Group, for helping in identifying, sourcing and managing the group buy of this diminutive gem from Lii Audio, China.

I believe about 14 or 15 of us made it to the group buy, based on @yogibear 's experience and postings of several videos on WhatsApp. I did several simulations using Basta! from Tolvan Data, and after several reviews and inputs from other FMs, we concluded on a design approach, and that is the basis of this project.

A timely loan/donation from Shiva Prashant of a pair of unused FANE 15 inch 250W Drivers helped support the project's lower end frequencies. Incidentally the FANE driver has been discontinued. A really good substitute is the Eminence Alpha 15A

Here are some initial specs:-

Full Range – Lii Audio F6 - TS Parameters (as tested by @yogibear below)

Efficiency	90 dB
Re	6.7 Ohms
Fs	84 Hz
Qts	1.32
Qes	1.7
Qms	5.92
Le	0.126 mH
Mms	6.58 grams
Vas	0.633 liters
Power Handling	10 W

Woofer – Fane Sovereign 15-250 Bass Driver TS Parameters from the tech sheet

Fs	43 Hz
Re	6.2 Ohms
Qms	7.180
Qes	0.810
Qts	0.730
Vas	144 liters
CMS	0.140 mm/N
Mms	90 grams
Xmas	4.35 mm

I am leaving out a lot of the conversations that led to the design decisions out of this documentation, for two reasons, one - way too much trouble - transcribing over 3 months of chats from a WhatsApp group and two - the intent here is to document the project.

So while the group buy process was in progress, our guardian angel @yogibear took care of the whole thing, the next step was to start developing the simulations so as to understand the process itself and since this was my first OB project, learning on the way.

Simulation with BASTA!


and the OB that produced this response


After looking at the unbelievably flat response of the F6, I quickly added the Fane in and this is what it looked like


and the baffle


of course, the F6 is much more efficient than the Fane, but that was expected. Bi-amping was a decision taken at this stage, based on the above

Designing the OB
Having very limited skills in CAD, I typically use the free web version of SketchUp to develop my designs, here are the final drawings, in MM.

The two speaker view - so that the FR offsets are understood


F6 Top Panel - BACK view


F6 Top Panel - FRONT view


FANE - Bottom Panel - FRONT View


FANE - Bottom Panel - BACK View


You can see the 'foot' and the 'hat' here at the bottom and the top respectively.
the ISO view here will help understand


The LEFT panel


and the RIGHT panel



I'll post some pics of the assembled speakers a bit later, need to shoot some nice pics - the phone pics are really terrible.

 

[Kannan]

A very well and superbly presented build log that can serve as a tutorial for many who want to charter this route.

 

[Naveenbnc]

hi CJ, its wonderful to take time and put everything in the forum !!!! Waiting for the real pics
looking at the graphs, F6 delivers above 90dB and Bass driver delivers between 70 to 80dB.
Does bi amping help in level matching or something ??

(by the way im extremely happy that this whole thing didn't evaporate in whatsapp chats alone!!!
Thanks again for adding to this forum. It helps many in future!!

 

[CJP]

Thanks everyone, this project would not have seen the light of day, if it weren't for the tons of support, encouragement, feedback of the OB -Audio-Mania WhatsApp group, several of whom are members here. And a very special call out to @yogibear for getting us ordained into pleasures of the OB sound, the countless videos and sample clips that he patiently posted, even catering to demands for specific tracks - pretty much on a full time basis. Furthermore, for @yogibear 's infinite patience and guidance both of which were critical to my learning process.

Another FM who was very key to the success of this project was Shiva Prashanth Hiremath (not sure of his handle here), for the Fane Woofer, else this project would have been considerably delayed. Shiva also helped in the listening sessions helping to fine tune.

Just got back from work, it is a bit late in the day for taking pics (I don't use flash as a matter of principle and do not own one), will shoot some pics tomorrow and post it.

Some initial pics from the construction phase



Panels are double sheets of 20mm MDF, the greening tinge is due to the MDF quality - it is external grade, it is more dense and uniform


Speakers on the way home in the car.


Rear View - you can see the 'hat' over the woofer, and the Apex Jr. plate amp. Yes, the speaker cables are Finolex 2.5 sqmm



first placement of the speakers as they were unloaded from the car. They have now been switched. You can also see my towers, and the sub. To the far left is my DIY rack that holds all the equipment. This whole lot takes up a full wall in the living room - very questionable WAF at the moment

Listening Impressions

Here are the listening impressions that I posted on the WhatsApp group in chronological order, it will also show how the sound has changed due to breaking in of the drivers.

• First Reactions
  
  To me it just sounds natural and right, there is something RIGHT about the sound, an elusive quality that you keep looking for when you audition equipment, but you find something missing all the time. I am just listening to the third track and it sounds so good...
  
  No resonance, bass is tight and very smooth, there is no perceptible transition between the F6 and the Fane. The Fane is crossed at 140hz. And the F6 is direct to the amp
  
  I'll play some bass heavy tracks later today and share my impressions. Yesterday rock was sublime. Jazz even more so, esp. female vocals like Norah Jones, was silky smooth.
  
  
• about a week later

1. The OB loves hard rock and metal - both the F6 and the Fane seem to revel in it. Clear separation of instruments, great vocals and rounded out HFs.
2. The Fane needs to break in, hard rock and metal have a lot of hard hitting bass - the speaker has no choice but respond. However, some more hours of usage will surely free up the suspension a lot more and I do expect bass to open up
3. so far I've been using the XO settings on the Apex Plate Amp, there is a bypass option and I'm planning to switch to the pre-amp's filters (much better quality and wider range) to set the XO for the woofers. Also gives me some level of consistency between the channels.
4. Shiva Prashanth Hiremath felt that the plate amps don't have the strength to really drive the bass. Perhaps an upgrade to more powerful amps are needed. We did discuss the possibility of using a Crown or something like that rated about 2000 Watts to power the woofers
5. which brings me to my next point - these babies are really power hungry. The F6 holds out - even at somewhat elevated volumes. But the Fane needs more power, I guess it is not so much about the efficiency of the driver itself - but the efficiency of the system overall. Producing copious amounts of bass requires copious amounts of amp power.

• about a month later, @Kannan asked me a very relevant question: How does the OB compare to my towers? and my answer follows

The OB - sounds open, airy, detailed, lush, articulate and expressive, great for music, pretty much all genres, but really shines on all genres of rock, metal, pop, jazz and Western classical. On movies and TV (e.g. GOT), the dialogues are clear, and place beautifully on the sound stage, the imaging is spot on. Turn up the volume and the speakers can heard all the way near our gate, about 100 meters away. What surprises me is the power handling capacity of the F6 - I do believe it can handle much more than the 10W that it is rated for, I've turned it up to near ear bleeding volume with hard rock and it didn't miss a beat - am not sure how long the VC can handle this abuse, but I did not see any signs of stress or distortion.​

My Towers (The Sentinels - named by wifey) - sound laid back, mellow, smooth and un-fatiguing for all types of music, it is more forgiving of bad recordings and MP3s. Vocals are bit more rearward placed on the sound stage, with a more vertically diffused image. Bass is more punchy though not quite as articulate as the Fane's in the OB. The diff being, the Fane's get dedicated amps, as opposed to The Sentinels. The towers shine on movies, Batman, Transformers etc., with good background scores sound almost as good as the movie theater or even better at home. And when turned up, The Sentinels can pound hard.​

above feedback is based on my 55 year old years, that can't hear anything beyond 17KHz...​

• and now....

Fantastic imaging, natural sounding for all manner of vocals​

Instruments are nicely delineated and articulate​

Bass is tight, articulate, deep and powerful - another woofer and a stronger amp would be welcome - I love musical bass ​

Rock, pop, hard rock, classical, baroque and metal - in short all genres - some thru very clean and effortless.​

The F6 is very detailed and will bring out everything from the recordings - good, bad or ugly - on truly good recordings, I can hear detail that I haven't heard so clearly before....makes me want to listen to my entire music collection again.​

​

and surprise - sounds great for movies as well, dialog, music and action sequences - the F6 does not even blink and the Fane Woofer just keeps on going too​

​

OB has been a revelation of sorts.​

​

Equipment​

Source	Oppo 103 - portable HDD plugged into the BD Player
DAC	Emotiva XDA2
Pre	Emotiva XSP1
Power	Emotiva XPA 200
Subwoofer Amp	Apex Jr 250 W
Cables	All DIY
Room treatment	none

 

[arunlouie]

What are those towers?

 

[Naveenbnc]

We did discuss the possibility of using a Crown or something like that rated about 2000 Watts to power the woofers

There was a discussion on whatsapp saying even branded amps like crown can not deliver the power they claim. Since the input smps they use, can not deliver that power theoretically. Just have a word with our diy amp designers. I don't know much depth about this subject.

Having said that, if an amp like crown claims 2000w, even if it delivers half of that, still its more than needed for ur application.

 

[CJP]

What are those towers are?

Those towers are also DIY, really nice. 4 way, passive XO. I made it about 5 years ago. Perhaps a topic for another thread.

There was a discussion on whatsapp saying even branded amps like crown can not deliver the power they claim. Since the input smps they use, can not deliver that power theoretically. Just have a word with our diy amp designers. I don't know much depth about this subject.

Having said that, if an amp like crown claims 2000w, even if it delivers half of that, still its more than needed for ur application.

Thanks @Naveenbnc - I've thinking about a suitable amp., for the moment however, the Apex Jr will do. Need to figure some funds for bigger amps.

 

[CJP]

some more pics



The OB in the raw

View attachment X15C9820.JPG

The F6 - there is light filtering through the black surround - it is very delicate




this view gives a sense of the delicate whizzer and the metal (I think) dust cap



and this is the family group photo...the placement is temporary, all the speakers and the rack in the left most side of the pic., are all DIY

 

[Kannan]

Superbly made racks. Amazing DIY work.
Truly deserves a trip to Bangalore again just to visit this setup, and ofcourse enjoy the serenity of the place he live in and his hospitality.....

A humble suggestion....an open baffle setup should technically have lots of freedom to the rear and the sides of the speakers. Of course, I don't know your space constrains, but if you can move out your towers, the OBs performance should be truer to their design.

 

[CJP]

Superbly made racks. Amazing DIY work.
Truly deserves a trip to Bangalore again just to visit this setup, and ofcourse enjoy the serenity of the place he live in and his hospitality.....

A humble suggestion....an open baffle setup should technically have lots of freedom to the rear and the sides of the speakers. Of course, I don't know your space constrains, but if you can move out your towers, the OBs performance should be truer to their design.

Thanks for the feedback Kannan.

The rack is pinewood, glass shelves and a 20 mm granite top - originally meant to keep a turntable

The OBs have about 36" between them and the wall. The sides are somewhat constrained I agree. The big boys don't have anywhere else to go.

 

[CJP]

some more pics taken this morning...


The rear view to show the 'hat' and the holes on the side that let the FR breathe and prevent cavity resonances




brothers standing side by side...

Superbly made racks. Amazing DIY work.
Truly deserves a trip to Bangalore again just to visit this setup, and of course enjoy the serenity of the place he live in and his hospitality.....

Kannan, you are welcome anytime...

 

[Sumanta]

Thanks for the feedback Kannan.

The rack is pinewood, glass shelves and a 20 mm granite top - originally meant to keep a turntable

The OBs have about 36" between them and the wall. The sides are somewhat constrained I agree. The big boys don't have anywhere else to go.

Place OBs outward and Sentinels inside.

 

[Kannan]

The big boys don't have anywhere else to go.

In that case, when you are listening to the OBs, short the towers speaker terminals with a small cable.

 

[CJP]

In that case, when you are listening to the OBs, short the towers speaker terminals with a small cable.

Kannan, the Sentinels are not connected at all...

 

[Kannan]

Kannan, the Sentinels are not connected at all...

While playing the OBs, which has a woofer for lows, put your ear close to the sentinel drivers, I am sure you will be able to hear them as well.
Just short it to prevent it.

 

[CJP]

Hello Everyone,

The upgrade bug bites! In search of more bass, I've decided to add another woofer to the OBs. Just playing with SketchUp at the moment, to see how it will look, while reusing as much as the material from the previous version.

 

[srinisundar]

I will be more keen to follow these.. However I will try first with my 18" fane woofer with Lii audio 6" driver and next jump on to twin woofer.

 

[maxsumit]

Hello Everyone,

The upgrade bug bites! In search of more bass, I've decided to add another woofer to the OBs. Just playing with SketchUp at the moment, to see how it will look, while reusing as much as the material from the previous version.View attachment 42423

Its a great idea, waiting to see how it goes.

 

[Svo]

Hello Everyone,

The upgrade bug bites! In search of more bass, I've decided to add another woofer to the OBs. Just playing with SketchUp at the moment, to see how it will look, while reusing as much as the material from the previous version.View attachment 42423

Did you end up building these. I just bought the F6 drivers and plan to pair them with two grs 15pf-8 drivers.

 

[skdas]

Did you end up building these. I just bought the F6 drivers and plan to pair them with two grs 15pf-8 drivers.

How you sourced F6 driver?