Confirmation on Sub Wiring?

[2023bronco]

I asked my master, Chat GPT, and was told this is how to wire up a 4 ohm Dual Voice Coil subwoofer to the factory (B&O) amp - presumed to be a 2 ohm amp.

Subwoofer:
VC1 + --------\
+ -------- Amplifier + (both factory + wires)
VC2 + --------/

VC1 - --------\
- -------- Amplifier - (both factory - wires)
VC2 - --------/

I picked a 4 ohm DVC sub because I hear they sound cleaner/less muddy than a 2 ohm DVC sub.

The diagram above is "parallel" wiring -- presenting 2 ohms to the amp. That all makes sense to me.

My only question is, do I really combine both + factory wires and both - factory wires (see far right side of diagram)? When I asked my master another time, it told me to chose one set of factory + and - wires, and it wasn't sure which set.

And yes, I'm going to use the B&O amp, at least for now.

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[Brian_B]

If you are using the Factory Amp (or two channels of an aftermarket amp - not common for a subwoofer), it's a 2-channel amp, so you would just go one channel per voice coil - no combining of wires on either the amp or the voice coils.

If you are using an Aftermarket single channel amp - you only have 1 set of wires coming from the amp, you combine your wires per your diagram above for the speaker (parallel) to the single channel from the amp.

 

[2023bronco]

If you are using the Factory Amp (or two channels of an aftermarket amp - not common for a subwoofer), it's a 2-channel amp, so you would just go one channel per voice coil - no combining of wires on either the amp or the voice coils.

If you are using an Aftermarket single channel amp - you only have 1 set of wires coming from the amp, you combine your wires per your diagram above for the speaker (parallel) to the single channel from the amp.

If I use both sets of + and - wires coming out of that factory B&O amp (running one set to each coil), that is a 8 ohm impedance, no?

I'm pretty dang sure this needs to be wired in parallel to get to 2 ohms, and the only question is which factory wires to use.

 

[Brian_B]

If I use both sets of + and - wires coming out of that factory B&O amp (running one set to each coil), that is a 8 ohm impedance, no?

I'm pretty dang sure this needs to be wired in parallel to get to 2 ohms, and the only question is which factory wires to use.

No.

It's two channels, each channel seeing 4 ohms. They aren't bridged internally (to my knowledge) - and that's why you probably don't want to combine them externally either.

You are correct, the only way you get to 2 ohms is to wire the VCs in parallel. The only way you get there with what you got is to wire your VCs in parallel (to get 2 ohms), then send it to a single channel - effectively cutting your amp in half (you['d have 2 wires not connected to anything from one of your channels). And you'd be better off going 4 ohms to two channels than doing that, or returning your 4 ohm sub and getting a 2 ohm version.

All that said, I thought the B&O sub was 4 ohm coils and the standard was 2 ohm (I know for a fact the standard is 2 ohm, just not sure on the B&O one)

 

[2023bronco]

Yeah, I want to keep the 4 ohm sub for the supposed clarity. I was just concerned the all-knowing Chat GPT was telling me I needed to run the DVCs parallel -- and could not simply connect one channel to one coil and the other channel to the other coil (which is pretty simple with Metra adapters).

And I searched all over B6G and didn't find specific instructions/photos.

 

[RagnarKon]

All that said, I thought the B&O sub was 4 ohm coils and the standard was 2 ohm (I know for a fact the standard is 2 ohm, just not sure on the B&O one)

This is correct.

At least for 2021-2024... not sure for 2025.

 

[2023bronco]

I think this is the first time I heard the b&o is 4 ohm - good to know!

 

[wanderingjim]

The sound system in mine had been upgraded by the previous owner, but they kept their sub amp and tailgate-mounted sub. I just got a new sub amp and installed an 8" Polk Audio sub in the B&O enclosure and it works great.

You can check this thread, it has the info you need including which of the stock wires are +/-. Here's another thread with a lot of good info.

If you don't want to cut the stock wiring, you can get this plug-n-play sub wiring kit from Amazon to connect the stock wiring to the new sub.

Lots of people go with an 8" Kicker sub in the B&O sub box but they mention having to remove some cover plate from the sub. I went with a Polk Audio 8" sub and it fits right in, I just cut/filed a tab off the B&O sub enclosure and drilled new mounting holes. If you go with a Polk Audio sub I'm pretty sure you'd need the DB 842 DVC.

I also put some polyfill in the B&O sub enclosure, and covered all flat surfaces on the enclosure with the sound deadening mat. I knocked on panels around the enclosure and on the floor in the cargo area and put sound deadening mat anywhere I thought might rattle. I do have a rattle on one particular frequency at higher volumes but at normal listening volumes (for us) it sounds great and doesn't rattle.

 

[2023bronco]

The 4-ohm Kicker on the factory B&O amp is better than stock for sure. A lot clearer / less muddy. It's not going to knock anybody's socks off with the factory power, but it sounds very clean and works well with the 4" Alpine coaxials I put in the dash and pods. Good enough.

I stuck sound deadening on the box, added polyfill (leaving the port open and clear of polyfill), did the latest subwoofer rattle TSB, and stuck dynamat on the trunk floor and around the box. No rattles.

Also, I used the Metra adapters and de-pinned them to reverse the polarity to match the factory wiring. Easy to do.

 

[KEYSG6]

The 4-ohm Kicker on the factory B&O amp is better than stock for sure. A lot clearer / less muddy. It's not going to knock anybody's socks off with the factory power, but it sounds very clean and works well with the 4" Alpine coaxials I put in the dash and pods. Good enough.

I stuck sound deadening on the box, added polyfill (leaving the port open and clear of polyfill), did the latest subwoofer rattle TSB, and stuck dynamat on the trunk floor and around the box. No rattles.

Also, I used the Metra adapters and de-pinned them to reverse the polarity to match the factory wiring. Easy to do.

The 4-ohm Kicker on the factory B&O amp is better than stock for sure. A lot clearer / less muddy. It's not going to knock anybody's socks off with the factory power, but it sounds very clean and works well with the 4" Alpine coaxials I put in the dash and pods. Good enough.

I stuck sound deadening on the box, added polyfill (leaving the port open and clear of polyfill), did the latest subwoofer rattle TSB, and stuck dynamat on the trunk floor and around the box. No rattles.

Also, I used the Metra adapters and de-pinned them to reverse the polarity to match the factory wiring. Easy to do.

What Metra Adapter and how did you de-pin? Looking to do the Kicker sub myself. Thanks

 

[23OBX2.7]

Having used mid grade 2 and 4 ohm subs, and currently running 2 oh, on 1000W @2 ohm, I cant detect any difference beween the two using flac, wav, or streaming 320 mbs.

The 2 ohm 12" is very crisp and punchy but maybe because its a $1K sub on $700 amp.....I paid way less on sales. Worth every penny.

 

[brkdncr]

Use your ohm meter setting on your voltmeter and check the stock and then check your new one. They should read close to the same.

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