Notes on a MY2018 M3 with Arc Audio KS125.4 and Eton Neo underseat woofers - Bimmerfest - BMW Forums

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > M3 & M4 > F80/F82/F83 M3 and M4 (2015 - Current)

F80/F82/F83 M3 and M4 (2015 - Current)
F80 BMW M3 sedan, F82 BMW M4 coupe and F83 M4 convertible forum. This 5th generation M3 and all new M4 features a 3.0 liter twin turbo engine (engine code S55) 425hp and 406lbs of torque! Heavy use of light weight materials makes this generation lighter and faster then the outgoing E9x M3.

Thread Tools Display Modes
Old 09-29-2018, 04:14 AM
Technic's Avatar
Technic Technic is offline
'Fest Sponsor
Location: Florida
Join Date: Jun 2002
Posts: 8,175
Mein Auto: 2017 M3
Notes on a MY2018 M3 with Arc Audio KS125.4 and Eton Neo underseat woofers

Sister gets new 2018 M3 and misses the "boom, boom" (her words) of her old 2015 335i with SWS-8 underseat subs

Unfortunately, the SWS-8 were gone with the car but not the Arc Audio amps. I had a new set of Eton B195 Neo in my garage planned for an F48 X1 that I never got, and a new add-a-sub harness/LOC-XD kit for HK systems with signal sense remote turn on that really works with the MOST OEM amp.

This was really easy:

KS125.4 amp prewired for power/ground remote and bridged 2ch mode (250W per channel):

Ordered CD Changer trunk trim P/N 51487246299 so KS125.4 amp can be installed on top of the OEM amp, and easily accessed for gain adjustments from top:

Installed add-a-sub harness with the LOC-XD on trim door for gain adjustment access (if needed):

Tilt seats (no need to unplug OEM harnesses) back and replace OEM woofers with the Eton Neo woofers:


1. OEM woofers were tested with the KS125.4 before the swap. Sound is louder and deeper, obviously. The problem is that this is too much power (gain at minimum) even at 7ohms, and BMW seems to have cheapen-out in the quality of the HK woofers from MY2015 to now. Much shallower that they used to be so now they flap and complain if bass is increased just a notch at the iDrive screen. Loud but not accurate at this power level. Definitely will sound better with a less than 80W per channel amp. Used to sound great with more than 100W per channel, but no more.

2. Then the Eton Neo. The Neo are Eton's new line of PnP woofers for BMW with shallow enclosures like in the 2-, 3-Series and X1. Unplug OEM woofer, plug New woofer in. This is also a 4ohms woofer rated for up to 200W rms per channel. No complains, no floppyness, just deep and accurate midbass at any volume with this KS125.4. No need for the Bass Boost adjustment of the KS, no need of anything over minimum gain on both the KS or the LOC-XD LOC. Just straight inputs from the OEM amp with no modifications at the outputs. Bass level at iDrive can be increased or decreased by taste, but just left in center will produce more midbass than the OEM amp at any volume.

The Neo are not subwoofers as the SWS-8, they do not go as deep as the SWS-8. But the Neo do not lack the solid midbass that the SWS-8 do. And still the go quite deep, loud and clean.

Sister is again happy.

Last edited by Technic; 09-29-2018 at 04:27 AM.
Reply With Quote

See More Related BMW Stories

Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > M3 & M4 > F80/F82/F83 M3 and M4 (2015 - Current)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump

All times are GMT -7. The time now is 09:34 PM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
© 2001- VerticalScope Inc. All rights reserved.