Focal IFBMW-SUB 8″: Anyone tried yet in F8X?

[Technic]

Originally Posted by tonydt1g3r

also I read this disclaimer in case you have a HK upgraded system

* Compatible with Base Edition audio system. Non compatible with Business or Top Hifi Edition


I think aftermarket amp is the way to go, I am not positive but I think I read somewhere the stock subs are like 7ohms? Hard to find a match and if you do, I think the stock amp is under powered.

http://f80.bimmerpost.com/forums/sho...83&postcount=5

[tonydt1g3r]

Originally Posted by Technic

http://f80.bimmerpost.com/forums/sho...83&postcount=5

what aftermarket amp is going to be 7 ohm stable

[Technic]

Originally Posted by tonydt1g3r

what aftermarket amp is going to be 7 ohm stable

Most (if not all) car amplifiers are stable at 7ohms. The HK OEM amp is not stable at less than 7ohms.

Therefore, swapping the OEM woofers with the Focal woofers will induce the OEM amp to be not stable.

What "not stable" means is that the OEM amp will be outside its output impedance range, which will provoke the OEM amp to produce more power than designed -which in turn makes the OEM amp run hotter than designed thus triggering its overheat protection circuitry or simply shortening its designed and useful operational life.

[808M3]

Originally Posted by DFozzy

According to the spec sheets, these look like 3.6 ohms. Are the subs wired in series from the HK amp?

If Focals are 3.6 ohms, hook them up in series, the impedance will now be 7.2 ohms. Focals make high quality car and home speakers.

[Technic]

Originally Posted by 808M3

If Focals are 3.6 ohms, hook them up in series, the impedance will now be 7.2 ohms. Focals make high quality car and home speakers.

Therefore they will be playing either the left or right channel only.

Guys again... the Focal woofers are not compatible with the HK system. The OEM amp ($1299 MSRP) could be damaged.

Out!!!

[whatheheck]

I removed my stock subs last weekend to see what it looks like, see how much space there is in the subwoofer enclosure and also measure the voice coil impedance. It is indeed 7.2 ohms.

I havent seen any specs on its frequency range and power handling.

I will be installing an after market sub amp this weekend.
I have a subwoofer amp I bought 2 years ago now for my daily driver that I didnt get a chance to install. So I will hook it up to the factory subs and see how the factory subs perform.

My Sony subwoofer amp has a stereo speaker level input (I will disconnect connection to factory subwoofer and hook it up to the Sony Sub Amp stereo input).

Sony sub amp puts out 290 watts on a 4ohm load and can handle down to 2 ohms load. It has both L & R subwoofer output terminals but they are wired in parallel internally as its a mono amplifier.

I will crank it up and see how the factory sub performs.

If I blow the subwoofers out no problem as I plan on trying a pair of the Earthquake Sound SWS-8X subwoofers anyway. Info below.

http://smile.amazon.com/Earthquake-S...s-8x+subwoofer

Note that my goal is just to improve the lower end and make the subs a little louder than the stock HK amp. I dont play music that's so loud that people hear the car rattling 2 miles down the road.

I will post what I learned here for sharing once I am done.

Dan

[Denso]

BMW M4 INSTALL

Dynamat front doors and rear quarters and under seat pockets for subwoofer access

Fitted front focal bmw custom fit mid range and tweeters

Fitted rear focal bmw custom fit 2 way speaker kit

Fitted 5 channel Hertz amplifier


I couldn't go with the focals as the ones supplied were for the e92 and the well was not deep enough by 25mm in the F82 so instead two 8" custom fit alpine match subwoofers running at 2ohms were installed.


Massive sound difference and clarity is amazing

[RocketBoots]

Originally Posted by Denso

BMW M4 INSTALL

Dynamat front doors and rear quarters and under seat pockets for subwoofer access

Fitted front focal bmw custom fit mid range and tweeters

Fitted rear focal bmw custom fit 2 way speaker kit

Fitted 5 channel Hertz amplifier


I couldn't go with the focals as the ones supplied were for the e92 and the well was not deep enough by 25mm in the F82 so instead two 8" custom fit alpine match subwoofers running at 2ohms were installed.


Massive sound difference and clarity is amazing

25mm?! That's crazy.

What Alpine subs did you use?

Any pics of the custom enclosure/fitting?

[Technic]

Is this an HK system?

Originally Posted by Denso

BMW M4 INSTALL

Dynamat front doors and rear quarters and under seat pockets for subwoofer access

Fitted front focal bmw custom fit mid range and tweeters

Fitted rear focal bmw custom fit 2 way speaker kit

Fitted 5 channel Hertz amplifier


I couldn't go with the focals as the ones supplied were for the e92 and the well was not deep enough by 25mm in the F82 so instead two 8" custom fit alpine match subwoofers running at 2ohms were installed.


Massive sound difference and clarity is amazing

[Denso]

Originally Posted by Technic

Is this an HK system?

No this was the bog standard UK non HIFI or HK system it was just a Crappy six speaker stereo system, frankly an embarrassing system to put in a £70k with options car in 2015.

[robbys3m3]

So since focal isn't selling the drop ins now (so I'm told), we installed the 'gladen' brand drop ins. For $500/pair otd, it's not too bad, but i don't think they really compare to a dedicated amp/trunk sub. They are for sure better than oem, but arent ground shaking obviously. as for impedance issues, the factory amp has only went into safety mode once, and that was at a much louder volume and output then what I normally listen to while driving. Regardless, I don't want to do a trunk sub, so I have a zapco dc1100.1 laying around I'm going to hook up to truly hear hear the woofers capability.