Front speakers blown, need factory head unit specs for suitable replacement

[matt-e]

Hi all,

I am looking to replace the front woofers on my girlfriend's mum's 2003 Cooper. She has the original factory install but has managed to blow both of these speakers leaving her with an annoying crackling sound. By ear it sounds like the original speaker is a 2-way coaxial incorporating a tweeter and it is the tweeter that has been damaged. This usually occurs because the amplified power from the head unit is underpowered for the speaker and therefore at high amplification provides a distorted signal which the tweeter can't handle. I did a degree in Audio Technology and can only assume the original install was badly matched to the head unit. I am looking to replace these two speakers for her birthday but I want to make sure the replacement speakers I put in have the right specification so they will not blow again so easily.

I am looking for the original head unit specifications; wattage per channel and impedance, and also the size of these front speakers. From what I have already read on here I believe these to be 13cm but what I am not clear on is can I replace this with another 13cm speaker or will I need a fitting adapter.

I have searched the internet all over but cannot find anything on these specifications. She also lives 180 miles away so I can't just pop round the corner to examine the car.

Thanks.

[cristo]

The fronts are a simple mid/bass unit (not coaxial) and the separate tweeter is higher up towards the inner
door handle release.

here's an excerpt from these threads from 2003, which talks about the fronts and rears and
replacements in some detail:

MINI COOPER :: North American Motoring - Question from Newbie on Audio Upgrade

MINI COOPER :: North American Motoring - what size are our front and rear speakers?

"The front door speaker on the base system is a 5.25". The HK system uses a 6". The grille opening, trim, and mounting depth easily accomodate most 6.5". Whatever speaker you install, in front, needs a bracket/spacer. This is simple to construct. I have made CAD drawings of the stock speaker, which gives me the info, I'd need to make a bracket to fit an aftermarket speaker. Let me know if you need help with the bracket.

The stock front speaker is pretty efficient (89.7 dB @ 1 meter with 2V input), and has reasonable low end extension (75 Hz resonance, Qt 0.68). It has good high end extension to 10 kHz. It's response is generally downward tilting (more lows than highs), and low excursion (2 mm). The latter are its relative weak points. I have a lot of data on the stok driver, if you're interested. (If you can make sense of it, it may help in finding a suitable upgrade)

I would prioritize finding a driver with equal or better efficiency, equal or lower resonance, and greater excursion (xmax). If you plan to keep the stock tweeter, you'll likely need a different crossover to work with most aftermarket drivers-they typically don't extend to the 9kHz crossover of the stock system.

I had been helping another MINI owner plan an upgrade, and found the Focal 165V2 kit to be my top choice for the front doors, if you don't plan to change the grilles, or cut the door trim. If you do have that in mind, then I think the Focal 7V4212 DB is by far the best woofer for the front door. I haven't found a tweeter efficient enough to work with it, but I do have a custom crossover in mind to "step up" the stock tweeter to work with it.

The stock 6x9 is a good driver. Efficiency 92 dB, resonance 74 Hz, Qt 0.83, excursion 3 mm, response to 6 kHz. I'd say that the limited high frequency extension is this driver's primary weakness. Any aftermarket driver with a good tweeter and crossover should yield a noticeable improvement. Finding something as efficient as the stock part may be difficult. If you find something only 89 dB (typical), the 3 less dB of efficiency is like driving the speaker with half the power. Keep this in mind while shopping. "

and this one:




"I just received and tested the stock speakers today. The front woofer is a 5.25", and is integral with a bracket/spacer. If you upgrade the speakers, you or your installer should fabricate a similar spacer for the speakers you choose. I don't know how to include pictures in these posts, but if you send me a PM with your e-mail I'll send pictures.

Since the front speaker is on a bracket, it really opens up the possibility of a variety of sizes of upgrade speakers. I recommend a larger speaker-6.5" to 7". I have also found that it is difficult to find an aftermarket front speaker with better sensitivity, better frequency response, AND more excursion (more bass capability). Many have 1 or 2 of these better, but I really think, you need to do better in all 3 to notice significant improvements.

I don't have all the data compiled into a concise report yet, but I can share info on the stock drivers off the top of my head.

DCR/Re: 3.5 ohms
SPL 1w/1m: 89.2 dB
SPL 2 VRMS: 89.7 dB
Qt: 0.7
Fs (resonance frequency): 75 Hz
xmax: 2.5 mm
Frequency response: OK: hole at 1kHz, rough response above 4kHz, with spike at 5kHz. Response extends to 10 kHz to meet passively crossed over tweeter (1st order, capacitor).
3/4" Voice-coil, good for 20-30 watts continuous"

[DaFlake]

Cristo posted a lot of great information but I also want to point out that if she has HK it may just be a dead amp and not the speakers. Also, if it is an HK system and the speakers are blown, you will need 2 Ohm ones for replacement.