From my experience with other cars and some reading up on the matter with bmw/mini, there is more to be gained from changing the amplification of the standard speakers than there is from changing them. That's not to say there isn't something to be gained from changing them, just that it can be quite underwhelming due to the poor amplification in the standard head unit. I'd hazard a guess that the standard head unit delivers around 15W or so. To truly find out, I'd have to get a scope on the outputs which I'm not planning on doing in a hurry as my scopes are old CRT based monsters and I don't want to take the interior apart.

The most efficient sub I found in my searching was the Focal IFBMW-SUB V2 @ 90.5dB/W. The MTX TX6.BMW claims a sensitivity of 93.5dB/W but it doesn't state a sensitivity for each component so I reckon they've quoted the tweeter as it's likely to be the most sensitive.

 

Thanks for getting back to me kei-86, if thats correct in the region of 15 watts i think it would be a waste of money replacing the woofers unless as you said i could amp them. Wasn't really looking to spend out, maybe i will put up with the weak audio. Did i read somewhere that the front door speakers and the underseat woofers split the same audio feed? Would also explain why they are so weak. When i turn the fader all the way to rear, i only hear the rear speakers, but when the fader is set to front, i can hear front speakers and feel the underseat speakers if i put my hand ontop of the grills under the seat. Weird 🙄

 

Yes you are correct the front feed goes to the mid in the door and the sub under the seat but in parallel so that lowers the load for the head unit amp. This is good news for upgrades though as the full signal is sent. Just intercept the speaker cables at the subs and redirect them to an amp. Take the amp output back to the sub where it will go to the sub and mid using the existing wiring. Most of the underseat sub upgrades are designed to cope with the original power in case you want to keep things simple and not use an amp. That's a bit of a halfhearted upgrade though and will probably produce a halfhearted improvement. I have reasonable experience of F56 upgrades so ask away if you have other questions.

 

Thanks for your response. I have been researching some more and found this.

BMW IS BACK - New OPTISOUNDBMW4X giving even more compatibility - Vibe

The start of July will see VIBE introduce the brand new OPTISOUNDBMW4X-v9 the latest version of the BMW Plug and Play speaker upgrade. This means the the VIBE OPTISOUND BMW range will now cover 95% of all BMW models meaning we have something for you no matter model or year! The New 4X model fits …

vibeaudio.co.uk

Let me know what you think?

Could also upgrade the underseat subs with the blam 8" ones, they are the lowest rms wattage i have seen. So im assuming as the door and woofer are wired in paralled that they would split the 65 watt rms, i.e 32.5w rms each if using this vibe amp. Would that be enough to power the woofers? Cheers

 

Couple of quick points as the Vibe site isn't giving me the text at the moment. The problem for me with the amp is you have to get to the back of the head unit to connect. Doable but more effort than getting to the speaker cables imho. Parallel doubles the power and reduces the ohms seen by the amp. So if they are both 4 ohms (they aren't so I'll measure them later) you'll get 125 watts rms at 2 ohms.

 

I have done some measuring and the 6" underseat is 4.8 ohms and the 4" door is 7.6 ohms. So in this case the total load seen by the amp on the fronts is 2.9 ohms and 61% power goes to the underseat speaker and 39% power goes to the door speaker. All academic as Vibe will take this into account but just for your interest.

 

Thanks shineywheels, really appreciate your help! My knowlege is very lacking in this department. Would the 7.8 ohm speakers in the rear be ok with the 65w rms at 4 ohms being sent to them? Would they approximately be recieving half the 65 watts? Would that still blow them?

So in theory if the front is pulling 2.9 ohms then it is receiving more than 65 watts, maybe closer to 90 watts? Sorry for all the questions 😅 i just thought it would be more straight forward for me as i won't have to find an earth point or run wires about to power/battery. Interested to hear your views. Was thinking i could upgrade the subs as i doubt the 6's will go low enough. But im not a bass head, just like a full sound