[How-To] Subwoofer Upgrade - Replacing/Upgrading the Factory Sub

[mpeugeot]

The Base auto system included in 2023 and later is a 2x2Ω 110 Watt... which is basically nothing for a subwoofer.

The original B&O system (2021-2022, and maybe early 2023?) was a 6-channel 660 watt total, with a 2x4Ω subwoofer output. I have no idea how much of that was 660 watts of power was devoted to the subwoofer itself, but if I were to guess they just split the amps up evenly and the subwoofer got 220 watts. Although I could also see them giving it up to 300 watts.

I honestly don't know the stats on the new B&O amp. It may be the same, it may not be, no idea. But I'm assuming the design is similar to the old amp/sub, because the power wiring feeding the amp is unchanged. Which means it's probably still a 2x4Ω DVC subwoofer.

---

If you are talking the Base audio system, several people tried to replace the factory subwoofer with a 2Ω DVC and found that it sounded muddled and somewhat sloppy. Which, considering the factory amp is only 110 watts, makes perfect sense. The minimum power level for most aftermarket 6.75" subwoofers is 150 watts, so 110 watts is definitely under-powering it a bit. Several people have said the ended up liking the 4Ω subwoofer better, which again... makes sense. Higher impedance means the subwoofer is easier to drive, which should help with the sloppy sound.

The 48CWR82 is going to want a 300 watt amplifier, which you are definitely are not going to get anywhere close with the Base audio system. And if my hunch is correct and the B&O amp is outputting only 220 watts, you aren't going to get it with the B&O system either. Which means it would make more sense to get the 48CWR84.

---

Also the Metra 72-6514 is not the correct connector for either the B&O nor the base amp. Not sure where you got that from.

It’s not possible for the B&O amp to output more than around 170 watts RMS (14v x 12 amps = 168 watts) except maybe briefly. I would expect it to blow fuses if the amp was drawing more than 170 watts (not all of which is allocated to the subwoofer).

There is no way that the B&O is pushing 660 watts, I might believe 280 watts total (110 from the head unit + 170 from the B&O dsp), even that's dubious. The 4 inch speakers are rated at 25w RMS, the 6.5's are probably 35-50w RMS, and the sub is most likely rated for 75-100w RMS.

5x25 = 125, 2x35-50 = 70-100, and 75-100 = 270 - 325 watts. Definitely, not 660 fantasy watts.

Sponsored

 

[Brian_B]

It’s not possible for the B&O amp to output more than around 170 watts RMS (14v x 12 amps = 168 watts) except maybe briefly.

Most amps (and speakers, for what it's worth) get rated by their peak power, not their RMS values. So not surprising.

The fuse is only 20A (I don't see separate fuse layouts for standard and B&O audio, but I suppose it's possible), so yeah, you are not wrong.

 

[mdube72]

The Base auto system included in 2023 and later is a 2x2Ω 110 Watt... which is basically nothing for a subwoofer.

The original B&O system (2021-2022, and maybe early 2023?) was a 6-channel 660 watt total, with a 2x4Ω subwoofer output. I have no idea how much of that was 660 watts of power was devoted to the subwoofer itself, but if I were to guess they just split the amps up evenly and the subwoofer got 220 watts. Although I could also see them giving it up to 300 watts.

I honestly don't know the stats on the new B&O amp. It may be the same, it may not be, no idea. But I'm assuming the design is similar to the old amp/sub, because the power wiring feeding the amp is unchanged. Which means it's probably still a 2x4Ω DVC subwoofer.

---

If you are talking the Base audio system, several people tried to replace the factory subwoofer with a 2Ω DVC and found that it sounded muddled and somewhat sloppy. Which, considering the factory amp is only 110 watts, makes perfect sense. The minimum power level for most aftermarket 6.75" subwoofers is 150 watts, so 110 watts is definitely under-powering it a bit. Several people have said the ended up liking the 4Ω subwoofer better, which again... makes sense. Higher impedance means the subwoofer is easier to drive, which should help with the sloppy sound.

The 48CWR82 is going to want a 300 watt amplifier, which you are definitely are not going to get anywhere close with the Base audio system. And if my hunch is correct and the B&O amp is outputting only 220 watts, you aren't going to get it with the B&O system either. Which means it would make more sense to get the 48CWR84.

---

Also the Metra 72-6514 is not the correct connector for either the B&O nor the base amp. Not sure where you got that from.

Thanks all for the great feedback @RagnarKon , @mpeugeot, @Brian_B - glad to have an awesome group of knowledgeable people in this forum. Going to move ahead with the external amp and subwoofer option after evaluating many options.

 

[KPLOBX]

If you watched my last video you will know that I installed the B&O subwoofer. This time I have upgraded that B&O subwoofer with a Kicker 8" sub!

Check below the video for a TON more information that I've collected.

Other videos/guides I've created on the topic of audio upgrades:

• [How-To] Factory Bronco Speaker Replacement
• [How-To] Amp Install - Kicker Key 200.4
• [How-To] FORScan Audio/Speaker Mods
• [How-To] Subwoofer Upgrade - Trim panel removal & Kicker install

AUDIO SYSTEM VARIANTS

As of now (mid-2023) there are four variants of audio systems in the Bronco. How you add/upgrade your subwoofer will depend on which setup you have.

2021 - 2022MY Six-Speaker
This was the audio system that was included in all non-Lux packaged Broncos. There is NO factory subwoofer, nor is any wiring available to support a subwoofer.

2023MY Seven-Speaker
Included in early 2023MY Broncos. This is identical to the 2021 - 2022MY setup, with the addition of an 110 watt amplifier and a 170mm (~6.75-inch) subwoofer.

2023MY Seven-Speaker with Sub Delete
Ford messed up and ran out of subwoofer components. Functionally the same as the 2021 - 2022MY setup. HOWEVER, it contains the wiring and the 170mm enclosure necessary to hook up a subwoofer & amplifier.

2021 - 2023 B&O
This is the premium audio system included with the Lux package. There are 7 speakers with a single subwoofer measuring 200mm (roughly 8") in size.

PICKING YOUR SUBWOOFER

At a high level... there are three decisions you need to make when picking a subwoofer:

• Voice Coil Impedance
• Speaker diameter & depth
• RMS power requirements

In addition those three items, there are other specifications such as frequency response, sensitivity, etc. etc. Most people will not have to worry about these items unless they are really trying to optimize their setups. Given I am gearing this post more towards the novice DIY type... I am going to ignore these items. However, you are free to ask questions about these topics or look online. In addition, if any of you car audio pros feel like there is an important aspect I am ignoring... post in in the comments.

Voice Coil Impedance

You will find that subwoofers intended for car audio generally come in two impedance ratings: 2Ω and 4Ω. There is a lot of electrical and power engineering I could dig into, but just to generalize it:

2Ω voice coils will be much louder and more more "boomy", as they can handle more power flowing through the voice coils. Those who dislike 2Ω voice coils often describe it as sounding very "sloppy", while those that like it often describe the bass as very "full" sounding. If you are driving those 2Ω voice coils with an underpowered amplifier, you run the risk of overheating your amplifier and/or creating very "muddy" sounding bass.

4Ω voice coils will have a more tight and clean sound. Uses less power than 2Ω voice coils, and generally more "safer" for underpowered amplifiers. For this reason... if you are running a factory amplifier rather than aftermarket, I generally recommend sticking with 4Ω voice coils. Those who like the sound of a 4Ω subwoofer would describe it as "accurate" sounding, while someone who dislikes 4Ω voice coils will often say it sounds "constrained".

Speaker Diameter

Generally speaking, the bigger the subwoofer the better. BUT, the bigger the subwoofer the more power and space it will require. Unless you are willing to devote your entire cargo space to a subwoofer, most of us will have to come up with some sort of compromise when it comes to the size of the subwoofer.

If you are mounting your subwoofer in the factory location—in the cargo area passenger side panel—you have two sizes available: 6.75" and 8" subwoofer speakers. BUT, there is aftermarket enclosures available—more on this in the enclosure section.

Obviously your subwoofer will need to be able to physically mount inside of whatever enclosure you select. This will be highly dependent on which enclosure and subwoofer you select, and there is a near-infinite amount of combinations available. The only real advice I can give here is "RTFM and measure before buying".

RMS Power Requirements

Obviously you need to pick an amplifier that is capable of powering your subwoofer. More on that in the next section...

PICKING YOUR AMPLIFIER

There is a TON of amplifiers out there in the marketplace. I definitely encourage you to shop around, and gather suggestions from the forum.

One of the more popular amplifiers is the Kicker Key 500.1, which is the amplifier I personally selected—largely because it was compatible with the Plug-n-Play Kit I bought. My brother—who generally knows more than me about car audio—also suggested the Kicker CX series of amplifiers. In my past I would have highly suggested AudioControl amplifiers, but admittedly I have zero experience with their current product offerings.

Arguably the most important part of any subwoofer amplifier is the amount of power it can deliver at a given impedance rating. It's probably easiest to explain this using an example...

Pretend I have selected the following components:

• Amp: Kicker Key 500.1
• Sub: Kicker Comp RT 48CWRT84

The amplifier I have selected has the following specifications. Notice that the maximum power output of the amplifier depends on the impedance rating of the subwoofer.

The subwoofer has the following specifications. Notice the recommended amplifier power is 300 watts. This is the recommended power output when the subwoofer's voice coils is wired in parallel.

What does this parallel business mean?? Well... there is two ways to wire a dual voice coil subwoofer. If you wire subwoofer in parallel, the impedance rating seen by the amplifier is HALF of the value of the voice coil rating. If you wire the amplifier in series, the impedance is DOUBLE the value of the voice coil rating. A 2Ω subwoofer in parallel will cause the amplifier to see 1Ω of impedance. If that same subwoofer is wired in series, the amplifier will see 4Ω of impedance. Wiring diagrams below:

In this case, our subwoofer has 4Ω voice coils, and when wired in parallel, the impedance seen by the amplifier is 2Ω. The Kicker Key 500.1 is rated for 300 watts and 2Ω impedance, which matches the subwoofer's requirements. So we're good to go.

Modern amplifiers are also typically packed with a ton of added features that you may or may not find helpful. Definitely read user manuals, check out reviews online, etc. etc.

SUBWOOFER ENCLOSURE

General speaking there are three choices for subwoofer enclosures:

• Using a powered subwoofer. This has the amplifier, the subwoofer speaker, and the enclosure in a single unit. The Kicker Hideaway series is a popular example of a powered subwoofer.
• Using an external enclosure. This can be as simple as an standard subwoofer box you stick in your cargo area, an enclosure that mounts to your tailgate—such as the Stinger TXFBB12, or even a DIY box you built yourself.
• Mounting it to the factory location. Three options for this:
  • 2023MY base audio enclosure - 170mm enclosure (~6.75")
  • B&O enclosure - 200mm enclosure (~8")
  • Aftermarket enclosure, such as the JL Audio Stealthbox.

Personally, I like the factory location as I value my cargo space, but obviously the choice is yours.

Whichever you decide... check your measurements.

HOW TO WIRE YOUR SUBWOOFER AMPLIFIER

Obviously this will vary widely depending on exactly what gear you purchase. So I am going to speak in extreme generalities. If you need help filling in the gaps, let me know.

POWER

Most people will have to pull their amplifier power from the battery, but the 2023 have the option to pull their power from the factory wiring, assuming they have a relatively low-powered amplifier.

Variant	Power from Battery	Power from Factory Wiring
'21-'22 Six Speaker	Yes	No
'23 Seven Speaker	Yes	Yes, but careful (12 ga. wire)
'23 Seven Speaker (Sub Delete)	Yes	Yes, but careful (12 ga. wire)
'21-'23 B&O	Yes	No

GROUND

Just about everyone will be able to use the ground near the passenger rear cargo area behind the panel. Those with the 2023MY may also use the factory wiring provided, but keep in mind the ground wire should be the same gauge as the power wire or larger (thicker cable).

AUDIO SIGNAL

This is where it gets interesting...

'21-'22 Six Speaker

Those of you in the unlucky 2021-2022 6-speaker camp will have to steal their subwoofer amplifier signal from the left and right kick panel speakers. There really is no other way around it. Of course, certain amplifiers and kits made by companies such as @plugnplaykits can make this task substantially easier for you, but fundamentally it all has to come from the kick panels.

Factory Setup

With Subwoofer Upgrade (Proposed)

'23 Seven Speaker / '23 Seven Sub Delete

2023MY Broncos have all of the wiring in place for an amplifier, regardless of whether you have the sub delete option or not. Upgrades are as easy as taking the old amplifier/subwoofer out (or their fake equivalents), and installing the new amplifier and subwoofer.

Note the 2023MY Broncos with the sub delete option will need to use Forscan to turn on the subwoofer output from the ACM. This output will be a low level (aka: line level) output, not a high level (speaker level) output.

Factory Setup

Factory Setup - Sub Delete

With Subwoofer Upgrade (Proposed)

'21-'23 B&O Package

The B&O package makes it tricky. The amplifier in the rear of your Bronco near the subwoofer is not just a simple amplifier. It is an entire digital signal processor (DSP) that also powers more than half of the speakers in your Bronco. That DSP talks to the factory Audio Control Module (ACM) over a digital connection using a protocol called A2B. Therefore you cannot simply replace the DSP with an amplifier.

There are several companies out there that have aftermarket equipment capable talking on the A2B protocol. BUT, if you are simply going for a factory subwoofer upgrade, your amplifier will have to daisy-chain off of the B&O DSP output.

Factory Setup

With Subwoofer Upgrade (Proposed)

MY PERSONAL SETUP

I have a 2022 Bronco with the standard 6-speaker setup. To feed the subwoofer amplifier I am using a Plug-N-Play kit from @plugnplaykits. That kit steals the signal from the front kick panels, passes it through a load resistor to clean up the signal a bit and give the factory ACM something to look at, and passes it back over the wiring harness to a Kicker Key 500.1.

OTHER THREADS/VIDEOS...

These are thread I've come across that I felt were extremely helpful. If you got one I missed, link it and I'll add it to this list.

Threads

• 2023MY Speaker/Sub Upgrade Megathread
• @jshapz - 2023 7 speaker subwoofer upgrade
• @cmcbronco - B&O sub installed on Base Bronco ….sorta….
• @John P. - John’s 2 Door Badlands Build (B&O Replaced with Active DSP)
• @Ksjrb03 - B&O sound system complete upgrade - Done

Videos

• Kicker Hideaway Powered Sub Install
• @1Five1 Garage - Interior Trim Removal and Soundproofing

FACTORY WIRING DIAGRAMS

Hope that was helpful!!!

I’m thinking of throwing a powered sub behind that panel, like a trunk sub. I can’t tell from the pics.. without the enclosure would I be able to fit a 11x19x5.5” box?

 

[RagnarKon]

It’s not possible for the B&O amp to output more than around 170 watts RMS (14v x 12 amps = 168 watts) except maybe briefly. I would expect it to blow fuses if the amp was drawing more than 170 watts (not all of which is allocated to the subwoofer).

There is no way that the B&O is pushing 660 watts, I might believe 280 watts total (110 from the head unit + 170 from the B&O dsp), even that's dubious. The 4 inch speakers are rated at 25w RMS, the 6.5's are probably 35-50w RMS, and the sub is most likely rated for 75-100w RMS.

5x25 = 125, 2x35-50 = 70-100, and 75-100 = 270 - 325 watts. Definitely, not 660 fantasy watts.

I'm just pulling numbers off of the B&O spec sheet... which admittedly is very sparse on information.

I know the B&O amp is fed by two separate power lines... do we know what the gauge/fuse(s) are?? That should be able to tell us pretty quickly what the ballpark numbers is. Ford's service manual lists 5 amps which is obviously wrong. I know the base audio system (and the number in the manual) has a 20 amp fuse, but I would assume the B&O amp is more than that.

 

[Brian_B]

know the B&O amp is fed by two separate power lines... do we know what the gauge/fuse(s) are??

There’s an Audio Processor 20A fuse under the steering column I think runs the B&O amp or the 7-channel discrete sub - but I don’t know for absolute certain

 

[mpeugeot]

I'm just pulling numbers off of the B&O spec sheet... which admittedly is very sparse on information.

I know the B&O amp is fed by two separate power lines... do we know what the gauge/fuse(s) are?? That should be able to tell us pretty quickly what the ballpark numbers is. Ford's service manual lists 5 amps which is obviously wrong. I know the base audio system (and the number in the manual) has a 20 amp fuse, but I would assume the B&O amp is more than that.

The amp itself is rated for 12 amps, not the fuse, my bad. I have it on my shelf in the garage.

 

[RagnarKon]

The amp itself is rated for 12 amps, not the fuse, my bad. I have it on my shelf in the garage.

Oh... like on a label on the bottom of the B&O DSP??

 

[mpeugeot]

Oh... like on a label on the bottom of the B&O DSP??

Yep

 

[RagnarKon]

Yep

Oh.... well if that's the case, then maybe the 20 Amp fuse in the manual is accurate.

If it is truly a 20 Amp fuse, then I agree. There is NO WAY that can be a 660 watt amplifier, and that spec sheet is just pure lies. It's just not even electrically possible. It's gotta be around 160 - 200 watts. Maybe 250 watts maximum.

Certainly explains a lot though. Always wondered why they designed the driver on the subwoofer the way they did (clearly prioritized efficiency above all else), but it definitely all makes sense now.

 

[MKZoom]

a power spec on a multi channel amplifier is not very helpful if you dont know how its calculated.
looking at the fuses can tell you a maximum long term power draw, but that also does not tell you much about the actual usable output. Music is VERY dynamic and multi channel amps with very different speaker types are going to be convoluting where/how that power is sent even more. i would recommend avoiding thinking of power at all when it comes to factory systems.
if you do choose to speaker swap you can monitor the voltage your speaker sees but really the better route is just using an LOC and your own amp. with whatever speaker you desire.

lastly, higher or lower impedance should not effect the something sounding "sloppy". while the damping ratio is important, you are likely not seeing much of a difference between a 4ohm and 2 ohm speaker. This impedance myth is widely spread.

 

[CalvinT]

It could be they're using the old IHF power rating. It was calculated from a 20 millisecond tone burst at one frequency in one channel. It's a single channel driven at a single frequency typically 1 kHz with 1% THD. It was used back in the 1970s to make cheap stereos seem good. It was called "music power."

The practice (for home stereos) ended when the Federal Trade Commission got involved with their own standards. The FTC rating required a 30 minute preconditioning followed with both channels being driven from 20-20,000 Hz with no more than the rated distortion.

For example a Pioneer SX-727 receiver had a music power rating of 195 watts one channel driven at 4 ohms. The FTC rating was 37 watts per channel, with both channels continuously driven into 8 ohms.

For some reason they never applied the same standards to auto sound systems.

 

[CalvinT]

A 12V amplifier driving a 2 ohm speaker can't put out more than 72 watts. Ohms law E=IR and the power law P=IE apply. Using those two equations you come up with P=I squared R. That's also assuming a perfect 100% efficient amplifier.

I think some very high end automotive systems can increase that by using a DC to DC voltage doubler. Then it's feasible to have an amplifier running on 24 volts. That could quadruple the power output.

 

[Brian_B]

RMS power yeah - you can’t exceed the average over time.

But sound isn’t DC - it’s a wave and it can peak much higher - just a function of how the amp is constructed. You will see a lot of audio components are rated “Peak” and you will see some fine print that has a much lower RMS power value

Here's an example - Kicker 8" sub that is popular. It's sometimes advertised as a 600W sub, but that's it's peak rating, it's really a 300W RMS speaker

The Kicker Key amps, however, are advertised at their RMS rating (at a very specific ohm load). They don't have a lot of peaking capacity (not a lot of capacitors to do that with due to their Class D and small form factor construction).

The difference between RMS and Peak power in Audio is significant.

 

[MKZoom]

and this is all without getting into the fact that the power rating on a speaker is a Thermal rating. it says nothing about the performance at that input.

A 12V amplifier driving a 2 ohm speaker can't put out more than 72 watts. Ohms law E=IR and the power law P=IE apply. Using those two equations you come up with P=I squared R. That's also assuming a perfect 100% efficient amplifier.

I think some very high end automotive systems can increase that by using a DC to DC voltage doubler. Then it's feasible to have an amplifier running on 24 volts. That could quadruple the power output.

the branded audio amplifiers are often running boosted rails, which would give them 20 some, 30 some or 40 some volts to drive the speakers with. of course, they still need to draw this power from the battery/alternator so there is still a limit on the maximum continuous power.

at the end of the day, the power numbers are not very helpful, not regulated, and do not correlate with performance or loudness. they should be ignored.

Sponsored