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4,981 Posts
Discussion Starter #1
Back from china and taking a break from working on cars to work off my jet lag. perfect time to throw up this build log.

As anyone who have followed us knows, we tend to do stealthy space saving SQ builds...but once in a while, we get a request for something a bit more...naughty? :)

Now we have done big bass type of builds before but this one truly stands out because through it all, sound quality was still a bit factor, and secondly, the vehicle we were provided with for the job - a 2013 Audi S5 - is not what usually comes in mind as an ideal platform for such a project.

Aside from the excitement of building such a system in a compact german coupe, there was also the anticipation of trying out the brand new Focal Kevlar line of speakers and subwoofers.

As many of you may know, my preference for very smooth, laid back midrange and highs have precluded me from using many focal speakers in the past. The K2P line was perhaps the most stand out example. The speakers are very robust and can produce an exceedingly high level of output with great clarity and detail, but it was simply a bit too bright for my personal preference. Hence, you very rarely saw a SiS build with them in the past.

However, with the release of the Focal FLAX speakers over a year ago, my opinion of the "focal sound" began to change drastically. that set really impressed me with its smooth, natural and airy sound, and from the first time i heard it, i was quietly anticipating the release of the higher end focals endowed with the same sonic characteristics.

With the release of the new Kevlar ES line, I finally got my wish. In additional, i got an ever further surprise with the release of the brand new Kelar series of subwoofers. These on paper looks nothing like the old generation of KX subs. Gone are the spectacular array of red magnets (a moment of silence please), but the new driver simply looks far more beefy and capable from an output standpoint.

Either way, it was with great excitement as we pulled the S5 into the shop and started going to work. Joey did virtually all the fabrication work in the trunk, while i concentrated on the interior elements and wiring. Jesse pitched in at the end to help install it all into the vehicle.

The goals:

1. obtain a nice level of sound quality utlizing the new Focal Kevlar line of speakers and subwoofers

2. while maintaining SQ, have the ability to get very loud interms of subbass output

3. virtually the entire trunk is available for the build with no need for storage space, but it should incorporate some unique aesthetic factors and not just a plain squared off panel; in other words, make it look cool. :)

lets get started with pictures of the car, once again, not what comes to mind when you think of big bass :)

lets take a quick look at the front midbass. becuase the door grille can be removed and popped on, this car gives us a unique ability to see the midbass driver after the car is finished. so here, you can see the new kevlar ES 6.5" midbass behind the factory door grille:

before going any further, lets take a quick look at the entire Focal ES165KX3 3 way component set. cosmetically, it isnt a HUGE change from the older KRX3, but the tweeter is pretty different looking, along with the passive xover. the midbass retains the old KRX's super beefy appearance, with a substantial motor behind the kevlar cone. overall, it still gives us the impression of a very high quality of fit and finish, very high output and midbass impact, but somehow, it looks even more business like now than before.

lets get back to the installation of the midbasses. first here is the stock door panel. the oem speaker was removed and the door sound proofed with a combination of GP STFU composite damper, STP cld damper around the speaker opening, and blackhole tiles on the outer door skin:

i think fabricated a set of adapter spacers routered off the oem speaker mount, and coated them with several layers of truck bed liner:

the adapters were then bolted to the door using oem hardware and the focal kevlar midbass wired up and installed:

the inside of the oem door cards also received a liberal amounts of STP CLD damper to help reduce resonance:

the passenger side door got the same treatment:

moving on to the midrange and tweeter. these i molded them into the oem a pillars and wrapped them with factory matching vinyl. the tweeters are aimed about 30 degrees more on axis than the midranges:

here are some quick build pics of the pillars.

first, the oem pillar was cut, ring baffles aimed and attached:

next, mold cloth was pulled, resin applied, and the pods reinforced from the inside via a resin/filler mixture:

then a few layers of filler followed by sanding got them to be smooth and blended:

i then wrapped them with a single layer of dark graphite vinyl:

and the focal ES KX midranges and tweeters were installed:


4,981 Posts
Discussion Starter #2
next come a series of wiring pics as it turns throughout the car. as with any car featuring a rear mounted battery, virtually all the wires were run down one side, in this case, the driver side. ziptied to the factory bundle every few inches or less.

there were no open spaces in the oem molex door plugs, but the oem speaker wires were pretty substantial, so i soldered new wires on right before the molex plug in the kicks, and then soldered onto it at the other end as soon as it enters the door:

moving onto the signal source. here is the oem driver side trunk area, with the carpet off. you can see the oem bang and olufsen amp residing on a plastic rack:

the stock amp was removed, replaced with a mobridge DA2 MOST pre amp, and the relevant cables lead up into the front of t he trunk area, secured once again to the oem wiring bundle:

as the car will be running a hefty amount of power, we decided to run dual zero gauge for power and ground wire. here joey fabricated a dual MIDI fuse holder bracket and welded it to the oem battery tie down to form a single metal piece:

and then the two stinger fuser holders were secured, the entire structure bolted down, and the wires run. the two zero cables runs out of the spare tire well, into the passener side trunk, and goes forward towards the front of the trunk, also following an oem bundle:

the two factory side carpet pieces had holes drilled into them near the front, with grommets installed, to allow the wiring bundle to pass through them:

the final thing before we move onto the trunk was to thoroughly sound proof the rear deck, rear deck cover and trunk lid, as we know there will be a lot of bass hitting them :)

so, lets take a look at the main part of the show. :)

a total of 5 arc audio xdiv2 amplifiers provide over 4000 watts to the entire system. two 1200.6 6 channels were bridged into a big 3 channel with one amp running each side of the front stage, while 3 1100.1 amplifiers are in master-slave-slave mode running the subs.

joey designed a metal amp rack to display the array of amps across the trunk opening once you flip down the backseat. quite a unique appearance:

though it may be hard to see, but all the wire connections are the amplifiers are done with ferrules and arranged in a neat manner:

there is also a strip white LED lights recessed in a metal channel above the amp rack, so when its turned on, it casts a nice cool white glow across the entire area:


4,981 Posts
Discussion Starter #3
lets take a look at the construction of this amp rack by joey, which started out as metal bars formed into a rectangular rack:

then joey laid the amps onto the rack, marked out, drilled and tapped the mounting holes for the amps so they can be bolted directly into the rack. these were then test fitted to ensure proper fitment:

the amp rack is secured at 6 strong points, two into rivetnuts at the top corners,two into rivetnuts at the bottom, and two bolts the sub enclosure that is in itself, secured to a metal brace bolted to the car. so evreything locks together and you can literally town the car with the amp rack or subbox

here is joey fabricating and attaching the various mounting feet to the amp rack:

at my request, joe also welded in two thin bars on the back of the amp rack, this allows me to ziptie and secure all the wires and cables that will be running from the five amplifiers:

finally, the whole structure was test fitted in the car, with amps and lighting (using a spare red led strip we had laying around), to ensure proper fitment:

the amp rack was then painted black and turned over to me:

the first thing i did was to bolt the four stinger distribution blocks to the back of the rack. two for ground, two for power. one attention i had to pay was to try and hide the wires as much behind the back of the amps as possible, so very minimal amount is visible through the gaps in between the amps.

then, i had to figure out a way to securely prop up the entire rack, with the amps on them, so i can access both the front and the back of the structure at the same time.

after some head scratching, i figured it out by ziptieing the rack to a middle shelf of a storage shelf at a set angle

and then proceeded to spend the next day wiring the whole thing up:

once iw as happy with the look, i took it off the shelf and laid it on the bench...seems like there are a lot of wires going all of the places, but there was some method to the madness as the key was hiding the wires and also trying to keep front stage signal wires away from the power cables:

before i put the amp rack intot he car, there were a few other housekeeping items to take care of:

to hide the gaps on the floor infront of the amp rack and behind it, joey fabricated two boards which i wrapped in blacket carpet, and then dyed them slightly lighter to better match the oem carpet:

here ist he metal bar that joey fabricated to secure the floating sub enclosure at the bottom, the back of the enclosure is bolted tot he amprack as mentioned before.

this piece of metal was test fitted and four rivetnuts were installed on either side of the trunk to allow it to be bolted solidly into place:

this bar was then painted black, and bolted to the car. the floor of the trunk sound proofed, and the two carpeted panels shown earlier were test fitted:

then, the amp rack was bolted to the car, and all the wires coming from the car side were hooked up...this was another half day process that i think permanently damaged my back lol.


4,981 Posts
Discussion Starter #4
finally, lets check out the subbox. as mentioned before, the customer wanted something more than a standard custom flat angled enclosure, so joey came up with a neat floating design that suspends three focal Kevlar ES 30 KX 12" subwoofers in a big sealed enclosure in the trunk. ontop of the enclosure, he added some visual detail with a combiation of ridges and inserts made from mdf, filler and painted acrylic.

quite a unique visual statement and distinct from our usual designs. :)

so, lets check out the remaining build pics.

one thing we didnt touch upon is the signal processor, and that is because it is tucked up under the rear deck and almost invisible. but here, joey first installed a few rivetnuts into the rear deck, and secured a board with its own threaded inserts:

and i secured an arc ps8 that controls the entire system:

onto the subbox itself.

the main box conists of a four flat sides of mdf, with bracing, and two curved sections at the top made out of kerfed mdf. here ist he initial assembly, and then as it got sealed and smoothed over and test fitted in the car.

the front baffle was fabricated, and bonded to the enclosure:

joey wanted the front to be very thick to withstand the weight and output of the focal subs, but he also wanted a visual break in the front baffle. so in between the inner and outer baffles, he sandwitch in a piece of 1/2" trim player, painted black to break up the thick front portion of the enclosure. here it is painted, and then test fitted:

this is the build up of the top trim above the enclosure. which consists of a series of backfilled pieces of mdf that slides into a channel ontop of the enclosure, each of these pieces have their own backfilled channel to allow a pieec of black painted acrylic to slide into, adding a lot of 3 dimension detail to the overall structure:

once he was happy with how it all turned out, joey startd wrapping all the pieces and painting the acrylic trim inserts

then Jesse took over and installed the wire terminals on the back of the enclosure and wired it all up, note the two brackets on the back of the enclosure that bolts to the amp rack.


4,981 Posts
Discussion Starter #5
and before we install the subs into the enclosure, i took some close ups of the Focal Kevlar ES 30KX you can see, completely different than the old ones...these are so much more beefy looking that its not even funny :) while i do love the array arrangements of the old focal subs, i cannot debate that they were quite expensive and did not ofer earth shattering output and low freq extension, these, visually at least, seems to indicate a different path all together.

and finally, the subs were wired up and loaded into the box, not the brakcet below the enclosure which bolts to the bar that runs across the trunk floor.

from here, it was just another coupla hours of yelling and cursing as jesse and i loaded this 150lb beast into the car, secured it and wired it in.

after some basic tuning, i hopped in and gave it a listen. first, with the subs turned way down.

right away, it is very apparent that these new kevlars follows the smooth and natural response of the FLAX where did i feel they were screaming at me like the previous generation of kevlars. but one thing they did keep was the spectacularly robust output and midbass of their predecessor...i dont think i never reached the upper threshold of their output before it simply got too loud for me.

this car had decent imaging and staging, with decent width, center and depth and very good height.

the midbass is really really strong...even if i turned off the subs, listening to drum tracks gave my chest a really good pounding. this has to be one of the strongest 6.5" midbasses i have ever used...for sure top 3.. the midrange and highs were very detailed but never overbearing, and i did turn thehighes up a bit more than normal knowing just how much bass it may need to cut through.

the bass...holy hell. okay, so i am not really a bass head, and this is not your SPL comp please take those things into account. But the first time i played bass mekanik's toccata in the car with the subs turned up, i honestly wanted to vomit when the big low note hit...despite this being a well sealed european coupe versus a hatchback or open vehicle, the amount of air moving inside the cabin was quite impressive, well beyond the typical voice modulating, vision bluuring level. i am not an expert but id guestimate that the output is easily into the 140 range.

there was also virtually no drop off below 30hz on the rta or judging by ear, so quite an insane amount of subsonic output.

but what really impressed me was the quality of the bass...when i turned the subs down to a normal level, it honestly sounded like a single sound quality 12" blended really well with the rest of the front stage, and despite us giving it less than preferred power, there was no overhang, it wasnt slow and kept up with all sorts of music.

if i had to compare it with anything, it would probably be the illusion audio c12xl, i would need to gain more experience with the focal sub to make an honest comparison, but i would say, these badboys are perhaps every bit as good of an all around performer as the illusion, and may even be a little bit louder. but again, this is just conjecture, i will do a few more of them and then be able to give a more accurate impression.

so needless to say, i am beyond impressed by the new focal kevlar lineup...if you had told me 5 year ago that i would make this statement, i would probably bet on the idea of the "focal sound" is so deeply entrenched in my mind...but with the flax and now the kevlar, i have a new found admiration for the brand and i only hope to use more of them in the future.

for more information on the components and subs used in the build, see here:

K2 Power | Focal America

thats it for now, cheers,


2,204 Posts
Beautiful as always.

494 Posts
What about the sub enclosure inversion? :)

Joey, Bing

Honestly, speachless!

An old local joke - How do you fit in an elephant in to a VW bug?


This was the first thing came to mind when I've read Audi S5 + bigish bass.

Unique setup of amps and speakers.

Just out of curiosity (hope I'm spelling words correctly - I don't bother to correct my self without a spell checker)


What was indeed the strongest 6.5 midbass you've ever encountered?



494 Posts
Yeah just that were I am the common engine volume is 2.0 atmospheric while bing is running a 2.5GT customized and that is a "tiny" difference between one legacy which is a very lazy ninja to another which is a total killer.


494 Posts
"it takes a ninja to kill a ninja" (youtube - ask a ninja)

It is a special brand - I guess you have to own one to understand what it is.

Anyways - waiting for Joey's and Bing's replies - wonderful install! wonderful!
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