Gremlin500 wrote:

Seems they all have the SAME subwoofer in the dash, not in the boot, according to the WM above.

Gremlin500 wrote:

Ah!

Sorry OP, I just realised that you already have the 825W, not the 380W system.
You can’t “upgrade” the 825W system simply by changing the speakers, forget it.
The speakers thing is only 380W>825W.
To upgrade to the “Signature” system is far more involved and expensive.
I find my basic 380W system has thumping bass if configured correctly, and the 825W system is even more so. Perhaps someone has disconnected the sub-woofer in the boot, or there is water ingress? It happens.

Technically maximum achievable just mid bass speakers in the doors can be replaced with signature speakers as amplifier will be able to work with them. But personally there is not much difference for my ear just waste of money.
To retrofit signature system will require massive job and loads of parts including seats (unless someone will be able to cut out space for speakers and wire them)
IMHO better spend it for some extra components if someone wants better experience than retrofit Signature system...

Sorry quote you and writing a bit different stuff after

Richie N wrote:

Ok, I believe the sub should be under the drivers seat but I can’t see it, hear it, or feel it under there. The L322 had the sub in the side panel in the boot and I am wondering whether early L405’s like mine did too.

I’m pretty sure I’ve see an L405 on YouTube with this grill and a sub was behind it. What’s the grill for otherwise?

There is no way the sub would fit here, as this space is normally occupied by the rear AC heater core & blower. Only if 3 zone climate is present it is empty.

Click image to enlarge

In all topix ddocumentsit says under driver seat. But driver seat could be a passenger side for UK models. I took this left panel off there were nothing... also no bass sound from this side. But in l322 sub is definitely there, i took it off to make more solid and not vibrate.

Quote:

In all topix documents it says under driver seat. But driver seat could be a passenger side for UK models. I took this left panel off there were nothing... also no bass sound from this side. But in l322 sub is definitely there, i took it off to make more solid and not vibrate.

It is true, L322 had the subwoofer under the rear side panel. I believe in the L405 the subwoofer was under the driver seat until the facelift in 2018:







After that it was moved under the boot and had a completely different shape.

I always liked more sub in the boot as it can produce more deep bass as if it hide under seat. I remember back in the days when I bought bmw 5series and switched music on the way back home it was awful. Then I read some reviews and all of the owners complained about sound distribution and how it sounds in the car.
So il ad that they learned the lesson and moved it away back into the boot.

Thanks for all the ideas and suggestions 👍

I have played with the settings as suggested and it is much improved. I turned the sub up to max and I can now feel it under the drivers seat - just about. It is very underwhelming.

I’ve seen a few videos on YouTube that suggest one of the best improvements is to put loads of acoustic material /sound deadening in the front doors and perhaps upgrade the speakers. Makes a huge improvement apparently.

Good to hear that. As I have same system and feeling myself comfortable with it.
I doubt you can do much better then you have in stock as it will require massive job to replace and married everything together.
For you convenience you can try to add some more insulation around the door's panel but I guarantee it won't be a huge improvement.
Just some curiosity, if you will do something let us all know.