[Heytree27]

Hi guys - I want to make some replacements/additions to my Logic 7 677 sound system in my e92. This is my first time modifying an audio system and will take the parts to an audio shop to have it installed and tuned.

1) The only thing I want to keep are all of the speakers.
From the documentation I read there are 9 channels total: 7 rated as 40w/2ohm and 2 rated as 70w/ohm. As far as I can tell, BMW does not publish RMS specs so I’m kind of at a loss as far as knowing how much power these factory L7 speakers can take?

I also plan on adding a Rockford fosgate 10 in sub in my trunk that is 2ohm/500w RMS. The amp is monoblock and rated as 500w rms at 2ohm or 300w rms/4 ohm.


2) I do not have satellite radio, phone or Bluetooth in my current stock logic 7 system. I want to replace the MOST HU with a joying HU that has TOSLINK OUTPUT. It also has Coaxial output and a sub out as well.

3) Because I plan on doing away with the stock HU and MOST altogether, I want to power my system with a 8 channel Audison AF C8.14 DSP Amplifier. This amp is rated as 100w rms at 2ohm and 65w rms at 4ohm. The ampl is bridgeable. I would lose the center channel - but I’ve been told that isn’t too big of a deal. The amplifier has digital input for my joying to hook up to it.

Another amp I am considering is the helix v eight mk2 which is 75w rms at 2ohm and also has optical input.

Would I need any adapters or harnesses? Or would I be good to go because I am not using the factory HU?

TIA

[ctuna]

The specs are actually published but may not be accurate.
Because they are at peak power and 10 percent distortion.
See first three in the block of links also.
Replacing speakers with drop in's is pretty easy on these.



http://www.e90post.com/forums/showthread.php?t=1144129
In the above has the output chip specs somewhere in the thread .
So for something like the underseat's the rms true power at 1 percent distortion
is something like 55 . But 1 percent is still a pathetic output spec.
(see entry 18)

BMW stereo types
http://www.e90post.com/forums/attach...4&d=1278871872
http://www.e90post.com/forums/showthread.php?t=352586
http://www.e90post.com/forums/attach...2&d=1266451970
http://www.e90post.com/forums/attach...2&d=1260829447
http://www.e90post.com/forums/showthread.php?t=641323
http://www.e90post.com/forums/attach...1&d=1209780605
http://technicpnp.com/menuDiagrams/d...e90_92_93.html
http://www.e90post.com/forums/showthread.php?t=343673
http://bmwcoders.com/forum/3-er-8/bm...1-e92-e93-291/
http://www.musicarnw.com/page-2/
http://www.e90post.com/forums/attach...1&d=1209780865
http://www.e90post.com/forums/attach...3&d=1169133185
http://www.e90post.com/forums/showthread.php?t=138949

The only amp that actually works with the BMW Most Bus is as a drop in is made by Mobridge
because the optical bus is a proprietary BMW Code.
This is the only amp that directly reads the code.

https://mobridge.us/products/

Technic Harness for Logic 7 retrofit will make life easier.
Also you will have to program out the Most Bus(optical Bus) for at least the SOS function if you replace
the head unit.

Most Audio shops are not good with BMW's do not listen to what they say.
You can get some real crappy results if you listen to what they say.
Helix Audio Fisher products are good.
Be sure to read the Audio build thread at the top of the stereo sub forum page.
Seems you are randomly choosing stuff and hoping it works without much research
so far.

OPTICAL input may be overrated especially in the stuff you are choosing.
Changing the Head Unit can be a can of worms and may not get you any better sound.
When people put in aftermarket head units they usually run RCA's to the new amplifier and use
something like a Technic Harness to adapt it to the old speaker wires.
Or if they are keeping the BMW head unit they reprogram it for Analog output or buy a analog
to Most Bus converter for the Logic 7 amp to get an Input.
If you buy a DSP amp you have to be ready to tune it.

https://musicarnw.com/ on the west coast and unexpected creations on the east coast are noted
as the two premier
BMW stereo shops in the US.

[Heytree27]

Originally Posted by ctuna

The specs are actually published but may not be accurate.
Because they are at peak power and 10 percent distortion.
See first three in the block of links also.
Replacing speakers with drop in's is pretty easy on these.



http://www.e90post.com/forums/showthread.php?t=1144129
In the above has the output chip specs somewhere in the thread .
So for something like the underseat's the rms true power at 1 percent distortion
is something like 55 . But 1 percent is still a pathetic output spec.
(see entry 18)

BMW stereo types
http://www.e90post.com/forums/attach...4&d=1278871872
http://www.e90post.com/forums/showthread.php?t=352586
http://www.e90post.com/forums/attach...2&d=1266451970
http://www.e90post.com/forums/attach...2&d=1260829447
http://www.e90post.com/forums/showthread.php?t=641323
http://www.e90post.com/forums/attach...1&d=1209780605
http://technicpnp.com/menuDiagrams/d...e90_92_93.html
http://www.e90post.com/forums/showthread.php?t=343673
http://bmwcoders.com/forum/3-er-8/bm...1-e92-e93-291/
http://www.musicarnw.com/page-2/
http://www.e90post.com/forums/attach...1&d=1209780865
http://www.e90post.com/forums/attach...3&d=1169133185
http://www.e90post.com/forums/showthread.php?t=138949

The only amp that actually works with the BMW Most Bus is as a drop in is made by Mobridge
because the optical bus is a proprietary BMW Code.
This is the only amp that directly reads the code.

https://mobridge.us/products/

Technic Harness for Logic 7 retrofit will make life easier.
Also you will have to program out the Most Bus(optical Bus) for at least the SOS function if you replace
the head unit.

Most Audio shops are not good with BMW's do not listen to what they say.
You can get some real crappy results if you listen to what they say.
Helix Audio Fisher products are good.
Be sure to read the Audio build thread at the top of the stereo sub forum page.
Seems you are randomly choosing stuff and hoping it works without much research
so far.

OPTICAL input may be overrated especially in the stuff you are choosing.
Changing the Head Unit can be a can of worms and may not get you any better sound.
When people put in aftermarket head units they usually run RCA's to the new amplifier and use
something like a Technic Harness to adapt it to the old speaker wires.
Or if they are keeping the BMW head unit they reprogram it for Analog output or buy a analog
to Most Bus converter for the Logic 7 amp to get an Input.
If you buy a DSP amp you have to be ready to tune it.

https://musicarnw.com/ on the west coast and unexpected creations on the east coast are noted
as the two premier
BMW stereo shops in the US.

1. I do not plan on keeping the logic 7 amp or hu.
2. This is what mobridge told me:
“ Ok so if you want to get rid of the logic 7 amp you have no need for a most adaptor on either end. It's going to be much easier to just run toslink out of the joying into an aftermarket amp like a mosconi. There is no point going toslink -> most then most -> toslink again. You might as well by pass most all together”

^ is that an accurate statement? If so , will the old speaker wires hook up to the Audison or helix amps? Without the need for an adapter or harness? Thats kinda why I was hoping with the amps being primarily 2ohm they would work with the factory speakers. But I don’t know.

3. What is the rms of the logic 7 , 9 output channels?

Thanks and I appreciate your response