Hiline Nav - Sound quality improvements. I've found something interesting!

[DMGRS]

Well guys, I've been having a root around my new Tourer and have found something rather interesting.

Most aftermarket headunits are around 4x40w @ 10% THD, a rather sizeable amount and perfectly capable of holding your own Bruce Springsteen concert while wafting down the motorway.

I've had my radio/amp module in bits this morning to try and sort out a grounding issue, and decided to find out what the MOSFETs in the amplifier module were capable of. I loaded the datasheet and...

We have just 4x 5.5w @ 10% THD! That'll explain the poor bass and lack of volume.

The BM24 Becker radio / amp module (from several BMW models, available on eBay) is a straight swap on our cars - simply purchase one and replace the amplifier / radio module in the boot (spare wheel well, right hand side) with a BM24 and you'll have 4x 38w straight away. You'll also have twin radio tuners, so a station list will be generated under the current station. You can then scroll through and select any of the pre-detected stations, rather than manually scanning.

Just a heads up before people go fitting aftermarket speakers etc. The speakers are fine - it's the amp that's the let down.

*THD = total harmonic distortion, a figure used to measure amplifier quality at a certain output. 10% is a pretty standard figure, however music will be heavily distorted at this level. THD needs to be below 1% for normal listening with quality.

[coab]

Hi Matty so in English for cavemen like me I just need a BMW Becker radio module? Thanks.

[DMGRS]

Indeed - you need a Becker BM24 (commonly known as just a BM24).

Massive improvement in quality - had one in the 75 Andy on here now owns, and just paid pretty silly money for another.

[Greeners]

Originally Posted by mattyprice4004

Indeed - you need a Becker BM24 (commonly known as just a BM24).

Don't you mean a BM54....?

[scoubix]

Originally Posted by Greeners

Don't you mean a BM54....?

No he meant BM24. I've had both, currently using a BM54. The BM24 is a direct swap as the connectors are the same, the BM54 needs a round-pins to flat-pins adapter. The sound quality of the BM24 is indeed a huge improvement over the standard Rover tuner, the BM54 improves over the BM24 but less dramatically.

[Ragman]

The BM54 also benefits from an upgrade that improves output but will set you back another £100 on top of the unit itself and the adaptor lead

[coolcat]

Originally Posted by mattyprice4004

Well guys, I've been having a root around my new Tourer and have found something rather interesting.

Most aftermarket headunits are around 4x40w @ 10% THD, a rather sizeable amount and perfectly capable of holding your own Bruce Springsteen concert while wafting down the motorway.

I've had my radio/amp module in bits this morning to try and sort out a grounding issue, and decided to find out what the MOSFETs in the amplifier module were capable of. I loaded the datasheet and...

We have just 4x 5.5w @ 10% THD! That'll explain the poor bass and lack of volume.

The BM24 Becker radio / amp module (from several BMW models, available on eBay) is a straight swap on our cars - simply purchase one and replace the amplifier / radio module in the boot (spare wheel well, right hand side) with a BM24 and you'll have 4x 38w straight away. You'll also have twin radio tuners, so a station list will be generated under the current station. You can then scroll through and select any of the pre-detected stations, rather than manually scanning.

Just a heads up before people go fitting aftermarket speakers etc. The speakers are fine - it's the amp that's the let down.

*THD = total harmonic distortion, a figure used to measure amplifier quality at a certain output. 10% is a pretty standard figure, however music will be heavily distorted at this level. THD needs to be below 1% for normal listening with quality.

The problem with a din/music power measurement is it isn't a set formula and doesn't really give a real world performance guide.
Manufacturers like to use it as a large number looks more impressive than an Rms ( root, mean, square ) figure which is much smaller but a far more accurate guide.
Just remember folks, double the power does not mean double the volume.
Look at the Db rating, a Db rating of 3db more is equivalent to doubling the volume.

Does sound like a good module for those that want to keep things oem but I can categorically state that the speaker systems installed in our cars, either the stock Goodmans or the HK system can be really improved upon as well.
Perhaps change the amp module and investigate a component speaker upgrade to really get it singing

[pollymol]

Hi
Will this new tuner/amp BM24 work with harmon kudron (spelling may be wrong) hiline speaker system. Thanks

[coolcat]

Originally Posted by pollymol

Hi
Will this new tuner/amp BM24 work with harmon kudron (spelling may be wrong) hiline speaker system. Thanks

The answer will be yes Sir, it would work with the Harman Kardon system

[suzublu]

Originally Posted by Ragman

The BM54 also benefits from an upgrade that improves output but will set you back another £100 on top of the unit itself and the adaptor lead

Flipping heck Col!! where've you been