Upgrading B&O System Subwoofer: Measuring power output to the sub from the B&O amp

[otter]

Hi all!

I'm knee-deep in a quest to boost the bass in our B&O sound system. Thanks to the wealth of information in this brilliant forum, I've got a solid plan for upgrading most of the speakers (front dash, kick panel, pods). However, the subwoofer has me stumped.

Per the B&O website (https://corporate.bang-olufsen.com/en/partners/automotive/ford/bronco), our stock amp is a 660W, 6-channel unit. But what's the power allocation for the subwoofer channel(s)? I'm guessing the 6 channels are split as follows: 2 for the left and right dash, 2 for the kick panel, and 2 for the sub. Based on forum-found wiring diagrams, it seems the pods and center dash are wired straight to the head unit, bypassing the amp.

Many have ventured down the path of replacing the subwoofer and adding a separate amp — kudos to them! But I'm on a simpler mission: just swap out the subwoofer speaker, aiming for a plug-and-play solution. I'm on the hunt for an 'improved' (whatever that means) shallow-mount 8" sub with dual 4-ohm voice coils.

I'm fully aware there's a ton of subwoofer talk on this forum. But my query is more specific: I want to know the actual power being fed to the sub via the stock B&O amp. The valuable threads here (like this gem: https://www.bronco6g.com/forum/threads/b-o-sound-system-complete-upgrade-done-.41031/) often involve dedicated sub-amps, which I'd prefer to keep as a Plan B.

Here's what's running through my mind:

1. Equal distribution: Seems incredibly unlikely (way too much power to the dash), but could it be a straightforward 110W per channel?
2. Allocation based on speaker type: This seems plausible — more power to the sub to handle low-frequency sounds.
3. Dynamic distribution: A fantastic idea if the Bronco were designed by audiophiles, but seems unlikely — the amps dynamically adjusting power distribution based on the audio being played.

My money is on scenario 2, but measuring power output is beyond my expertise. It feels like a task for more than just a multimeter.

So, has anyone here untangled this enigma? Any thoughts on how the B&O DSP might interact with a new subwoofer speaker?

Thanks for sticking with me through this post. Any insights or advice would be massively appreciated!

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[MKZoom]

every channel is the same power, but the sub has 2 channels driving it.

 

[the314boss]

otter,

did you ever get anywhere with this? i just did the swap of all dash speakers and rear pods in a B+O system... might do the kick panels as well, but "rattle battle" is my first priority.

i'd like to approach it with the same thinking you noted above; use the factory amp amp and mod the driver and box (i.e.: seal port, polyfil, kilmat the enclosure and surrounding area).

 

[Ph4nt0m]

Hey all,

Just came across this thread and figured I’d share a bit about my experience with the rattle battle and a time crunch for a 12 hour drive I had a week later.

I’ve used sound mat, polyfil, sealed (then unsealed the port), cloth tape, foam blocks, you name it and still had issues with a buzzing/rattle from the stock B&O sub. I was going insane and had 30 hours til I hit the road and I was not about to deal with it for that long a drive.

I discovered after eliminating all other rattles, the real issue was that the speaker cone travel was smacking the magnet. No solution I could think of other than getting a better speaker itself. Knowing I couldn’t do a full sub and amp upgrade by then, I had to find anything that would just be clean for the drive.

I hopped on Amazon and found this for about $70. It’s a low powered, inexpensive, 8” JBL sub that was designed for drop in replacement on older cars whose subs have blown over the years.

200 watts RMS, 800 peak, single 4 ohm impedance and a sensitivity around 88dB.

The quality for the price is much better than I was expecting. Really solid speaker. The outer ring mounts within the limits of the box (except the small plastic alignment tab at the south end of the opening).

I spliced the two positives and two negative leads going to the sub from the factory speaker wires, drilled a couple new mounting holes, got it in and tried it out.

As I was expecting, it’s wildly underpowered so it’s quieter when EQ is flat. Turn up the bass a little and it is without question a cleaner sound. Being that it’s underpowered, I think it’s not the most responsive setup but I could finally listen to music and not cringe.

All in all, if I was never going to do a full upgrade to the sub I would say this is a solid option to try out for $70 and help solidify whether a full sub and amp setup is worth it to you.

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