Hi,

Since I got the car, a 2011 Mk3 Focus, the rear speakers were shot, i had to divert the fader all the way to front so good music could play. I bought a pair of 45W MTX coaxial speakers. Installed them using some plastic rings, and adaptor cables for the wireing. And now, the rear speakers have a really low output volume, the output is so low, bass is not really heard from them. What I did wrong? The factory speakers were only 25W, is the differenece in power that caused this volume drop?

 

Thanks!

The stock headunit has a TDA7386 amplifier IC. This amplifier IC has a rated power of 4 x 49 Watt. This however is the theoretical rated power at an input (battery) voltage of 15,2 Volt.

At a much more realistic input (battery) voltage of 13,2 Volt the rated power of the amplifier IC is just 4 x 24 Watt. The standard 25 Watt speakers are matched to the output of the amplifier.

Your new rear speakers (compared to the original speakers) require double the power from the amplifier to be driven properly. The radio amplifier simply does not have the ability to deliver this power. As a result of this the volume will be much lower than the original 25 Watt speakers. Most aftermarket speakers will also perform a lot better when driven by an additional amplifier instead of a radio amplifier.

In this case I would also replace the front speakers to equal the power of both the front and rear speakers. If the radio amplifier does not have enough power to drive the speakers properly it is highly recommended to install a suitable amplifier between the radio and the speakers.

Thank you for the info, I think I will focus on replacing the rear speakers with stock ones and save the speakers for another project, as installing an amp is two much of a spending struggle.

Hi all,

Hope you don't mind me hijacking this old thread - I just stumbled across it looking for speaker advice.

@JW1982 - I have a 2010 Mk2.5 Focus, with a dead front passenger speaker. Last time it went, I just found a stock speaker on eBay and did a straight swap, happy enough with the results as I'm still just using the stock head unit (Blaupunkt Travelpilot FX). This time, though, I'm considering replacing both front speakers with half-decent coaxials, in the hope of improving the sound a bit.

Based on your knowledge of how they're powered, am I going to get bad results doing this? If I want acceptable volume, should I just get another stock speaker and not try to improve it? Like Octave, I don't really fancy the trouble of paying for and installing an amp, and I've no idea on the output of the Travelpilot unit unfortunately, struggling to find any spec info.

Any advice gratefully received.

Also @Octave, how did you get on in the end? Did you get results you were happy with without installing an amp?