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New f55 - Need to upgrade stereo

32680 Views 39 Replies 13 Participants Last post by  24seven

Just got my new 5-door diesel. To get a good deal I bought a demo-car which did not have the HK stereo option (Basic - 4 door speakers and small under seat subs). Love the car so far apart from the sound system which is really poor.

I plan to start with a building a under-boot-floor-sub, this weekend and then upgrade the door speakers later on.

My first thought was to get speaker signal from one of the rear door speakers, but I guess they have a lowcut at 100hz or so, does anyone know? I could off course remove a seat and get signal from one of the under seat subs, but I would prefere to tap in to a full frequecy source.

Any suggestions regarding tapping into the factory audio system are welcome!

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I don't believe the underseat speakers are actually subwoofers, just normal woofers. The crossover in the basic speaker setup is integral to the head unit so I'm not convinced it's possible but could be wrong

The HK setup is completely different and takes a digital feed from the head unit into a DAC amplifier and then filters the frequencies to the various speakers and subwoofers.

Thanks for your reply!

I guess my best bet is to take the signal from a under seat woofer, and hope that I have enough frequency adjustment on the amp that I´m adding to make it sound decent.

Read somewhere that the door speakers where 2ohm? which narrows the selection of replacement speakers down...
My aim was to finish the sub this weekend, but now the car had started popping out of first gear, so I'm not shure if I will keep it since this took all the fun out of buying a new car...
The biggest issue with the standard stereo besides lack of clarity, engagement and volume, is that it seems to have some sort of auto leveling loudness. Lets say you listen to a track at a certain volume, when the bass drum start playing (does not really matter what typ of music it is), the music sounds like you would expect for about 3 seconds and then the stereo cuts the lower frequencys changeing the sound drasticly. If you then lower the volume the lower frequencys are "reactivated" but if you raise the volume again they will drop after about 3 seconds. I know that this is done to eliminate distorsion, but other car stereos have a much more refined way of doing this, the inconsistansy is killing me.

All in all I would say that the standard mini stereo is about the worst sounding system of all cars In the price range.

I dont think that the under seat woofers are fullrange, there is some kind of high cut involved. Sorry the "taking feed from a underseat woofer" to get correct signal you would offcourse have to get signal from booth under seat woofers to the amp.
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Yes there is a "speed volume control" on the standard f56 sound system, I've tried it in off, max and middle position, but it does not solve the "auto loudness" issue.

The current situation with my car is that it will probably go back to the dealer next weekend at the latest. They've had it since yesterday trying to replicate the popping out of gear issue, and investigating the high fuel consumption.

There will subsequently not be a subwoofer build or audio upgrade, atleast not in this car.

However, I now drive a Countryman SD Worx loaner and find the Harman Kardon sound System in that car pretty good!
Ok, before I contradict my self regards saying I thought the sound was good, I listen to the radio mostly and have not heard this effect you speak of.
BUT using the USB input I have, and I am so glad you've mentioned it (you cannot believe how glad, as I though I was going mad as I've had problems with my ears lately and thought it may be that).
I have in fact borrowed music on an SD card and it's the same as through my Iphone.
Is it the same for you on the radio? Although I feel it's cuts the highs and sounds less clear but it's seems more to sound like a subtle volume lowering.
It bugs the f**k out of me, if I'm not the only one! I'm going to complain to the dealer.
Hi Matt,

Sorry, I never listen to the radio but I would guess the issue will be the same at louder volume. That makes atleast two of us hearing the issues with the standard sound system.

My car has been at Mini for a week due to a faulty gearbox. this, unresonably high fuel consumption, and a series of shortcommings that I guess I could have found with a more rigourus pre purchase investigation, but simply expected to work as good as other cars, has really put me off from the car.

The dealer refuse to take it back and offered me a trade in price about 3000 dollars lower than original purchase price after 3 days of use.

Will have to pour money in to it to even consider keeping it now and dont just take a loss to get it off my hands. Yes I am passionate about my cars :) and if the passion fades, the car goes.

Looks like there will be a stereo build after all...
Thanks for the encouragement, good to hear that it is possible get back to liking the car again, It has not really felt that way lately...

In an effort to get the feeling back i started and finished (almost) the under boot flor sub. The space under the boot floor is 5" deep, I'm using a shallow 10" Hertz sub and a hertz amp, there will be about 15mm space between the boot floor and speaker. The box is 15 litres, which is on the small side but the speaker is made for small enclosures and has 17 litres as a sweet spot so I guess it will be close enough to sound decent.


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As I dont want to cut in the wiring loom, the plan is to make 3-way splitters that plugs in to the under seat woofer (high level) signal, with one end still connected to the woofers and the the other to a longer cable going back to the amps high level input. The amp has auto start when a high level signal is detected.

Have not found any info on if the signal to the underseat woofers are fullrange with a high pass filter on the speaker or if the frequencys are cut in the headunit. If it is fullrange I will most likely get a 4-channel amp instead to drive booth sub and new front door speakers.

Fokal makes replacement speakers for BMW which looks like they could fit the Mini.
Good luck sounds complex.let us know how you get on
Thanks! I might need it :) I've soldered my way into factory amps once or twice before to make simular installations, but you never know until it's done.

Had all parts for the sub-build lying around, so there is still budget for other mods that would make me like the car again.
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After doing a bit more research, it looks like it would be fairly easy to upgrade the underseat woofers to one of the 8" aftermarket BMW upgrades availiable from: Focal, Rainbow, Gladen, SWS, Match, Bavsound etc.

Might try that and with an amp first...
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Ok, installed Sws 8xi subs under the seats driven by an amp, helix Match 4" coaxials in the doors and its a HUGE improvement. Still have some testing to do with setting levels on the amp.

I would suggest everyone with the standard soundsystem to at least change the front door speakers to quality coaxials as this makes a real differance in sound quality.
Yes. They sound decent for the price. Sounds much better than the oem speakers.
Looks like a good kit. Looked at all the simular kits (without included amp) but ruled them out because I did not want to make a hole in the windscreen pillars for the tweeters, and went with coaxials instead.

The speaker signal from the factory stereo is very tweaked EQ-wise (to make the oem $2 speakers sound anywhere near decent). This means that an external DSP or Amp with DSP is needed to to correct the signal or it will never sound really good.

I'm trying to solve this myself at the moment and right now a Mosconi DSP amp looks like the best solution.
Have not seen any sites that sell them, and I guess they would be on backorder as everyting else, or did your dealer sort you out with a pair?

Have so far spent half of the HK-option, but not keen on spending alot more since getting a really noticably better sound than the HK-package would involve rebuilding the doors to accept 6,5" and a 10-12" sub in the trunk.
Hi Stevens,

Its not like BMW, allthough alot of BMW audio components are used.

The HK option has an amp in the trunk that feeds from speaker level from the stereo. The basic stereo has a full range signal (allthoug heavily EQ:d) under the front seats.

The front doors and under seat speakers are paralelly connected under the seats (++ --) which makes the amp load 2ohms. This is one of the reasons why its not a good idea to drive the door speakers on the oem stereo and upgraded under seat subs on an external amp. Disconnecting the under seat woofers from the oem stereo makes the impedánce higher and result in lower power to the door speakers.
Sorry for the late response. As I don't have the HK-system, I can not be 100% shure, but from what I read before I started changing speakers in my car, the HK-system also feeds of speaker level. It would be easy to check when you get the car though. I´ve also had BMW:s with digital signals between HU and AMP before, so was a bit surprised when I read that Mini used speaker level to the HK amp...
They are wired in parallel at the at the under seat woofer connector. I took the feed from there.

I removed the bolts holding the seat sliders and tilted the seats (and sliders) back to access the woofers without disconnecting the airbag wires.

The problem is that the factory signal is so heavily EQ-ed (to make up for the crappy standard speakers) that there is just no way to get a decent sound without a DSP of some sort that flattens the frequency response of the signal. I does not matter how good speakers and amps you buy if the signal going in is bad...

I'm in the process of deciding which DSP to go with and what amps. Space is so limited in these cars its almost impossible.
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