Gladen + Mosconi to M135i. Pics and problem!

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Gladen + Mosconi to M135i. Pics and problem!

Post by ixi » Mon Jan 29, 2018 4:49 pm

Hi there!

I am doing a quite ambitious audio upgrade to my 2016 BMW M135i. I have run into a small trouble and it would be great if someone here could give me ideas how to troubleshoot? I know I'm asking a lot so I try to detail my situation as well as I possibly can so that you'll have all the relevant info.

As a starting point the car has Professional Navigation and Hifi-package. So one step below Harman/Kardon. I felt the sound was okayish but I'm a bit of an audiophile and this would be my first time doing bit more extensive audio upgrade.

I am not that concerned of the back speakers as I believe the audio should come front as the music usually does. But for the sake of PDC gongs and desire to be pretty close to stock system (apart from sound quality) I'm keeping them connected.


Gladen 201 EXTREME set to replace everything I have in the front.

Mosconi Gladen D2 100.4 DSP 4-channel Amplifier with DSP so that I can adjust the sound and in general run the power hungry Gladens

BMW Hi Fi AMP Connector Harness for using the existing wiring in the car as much as possible without the need to cut and splice your way to error code madness. ... KR&vxp=mtr


I did the build over the weekend. Everything went relatively well although the underseat woofers were quite painful to change due to the lack of space. I disconnected the center speaker as I don't have need for it. In the back I have the OEM set, did not touch them.

So I've got that Gladen set in the front and the Mosconi amp powering them and the OEM back speakers. But the problem is that I have messed up the wirings somehow. Or that is my diagnosis anyway.

From the connector harness I connect all the four RCAs to the four inputs of the Mosconi (on the left corner):

And from the connector harness I connect the Front Right, Front Left, Back Right and Back Left wires to the channel outputs. The manual tells that channels 1&2 are for front and 3&4 are for the back speakers.
I set the input to be Low level (I think it is) and that's it.

When I play music and try to adjust the sensitivity level nob on the Mosconi for channels 1&2 it does nothing. But turning the 3&4 affects both the front and back speakers (!?). Also when I adjust the fader from the iDrive to play from the back nothing is audible. But when I set it 100% front the back speakers play as loud as front speakers. (Or actually louder as they seem to be much more sensitive than my Gladen front set).

Also there is something bit wrong in the audio quality I think. I can't put my finger on it exactly but not fully happy with the audio quality.

Now after finding these problems I took off the wiring harness and plugged back the OEM Hifi amplifier. And everything works. Fader works and in general the sound quality is okay. Much better than starting point probably due to the upgraded speakers. However I think it's running bit out of oomph as it's not that loud and bass could be bit stronger.

Does anyone have any idea what to do? I think I've wired the Mosconi amp somehow wrong but can't really tell how it should be then.
I am considering dropping the back channels from the mix altogether but before doing that I was thinking maybe someone has an idea how I should do the wiring?

Very thankful for all the help!

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Re: Gladen + Mosconi to M135i. Pics and problem!

Post by streamer » Sun Feb 04, 2018 4:37 pm

From memory the HiFi system doesn’t have separate tweeters so I believe the front door speakers are wired off the under seat subs - which cables are you using from the eBay harness back to the speakers? Could be they are mislabelled but the fact everything works normally when you switch back suggests a simple wiring issue. I had to go through a bit of trial and error on my install to get the connections right.

Also, the output from the OE head unit/amp will be heavily equalised (to compensate for the lack of tweeters in the standard system) so you need to utilise the Mosconi DSP to flatten the curve OR code your headunit accordingly.

I’d also suggest changing to the high-level input mode as you are connecting the speaker level outputs into the Mosconi. Low-level would be used if connecting to a line-level output.

Good luck!

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