Part 4: B&O Subwoofer Replacement

[Mav_Owner]

This is the fifth of six long posts; on the B&O sound system upgrade of my 2024 Ford Maverick with Lariat trim. Here are the titles of the 6 posts:

Part 1: Introduction and Conclusion of B&O Sound System Upgrade

Part 2: B&O Front Door, Tweeter and Rear Speaker Replacement

Part 3: B&O Center Speaker Replacement with a 4 inch Speaker

Part 4: B&O Subwoofer Replacement

Part 5: B&O Upgrade, Subwoofer Amp Installation

Part 6: Best Way to Install Kicker 6.75” Sub into the OEM Enclosure

Components for Subwoofer replacement:

- KICKER 48CWRT672 CompRT 6.75" Subwoofer, DVC, 2-ohm
- Door Speaker Adapters Fit for Dodge/Chrysler/Jeep 6X9 to 6.5 Inch Black

Since I posted this thread I have learned a way to install this subwoofer into the OEM enclosure with modification to the enclosure. I only wish I had thought of it for my installation. Please see Part 6 for details.

I selected the KICKER 48CWRT672 because of the experience and results with the 8” Kicker subwoofer installation in my son’s car. I gave a quick look at using a 6x9 inch replacement but good ones, were coaxial speakers and had to be bought in pairs. Both of which I did not want or need. I took the OEM subwoofer enclosure out of the truck and took measurements. Using the Kicker dimensional drawing, I knew I could make this subwoofer fit in a modified OEM enclosure. I wanted to keep the OEM enclosure because it fits a hole in the bed of truck which serves as a port for air passage. Below are photos of the OEM subwoofer and enclosure:

When selecting a speaker or subwoofer its peak power rating is not the specification to use. Peak power only represents the ability for a speaker to survive a surge in volume for a few milliseconds. Root Mean Square (RMS) power handling is the primary factor when selecting a subwoofer, speaker or amp. RMS power handling represents the ability of the speaker/subwoofer to sustain that power for a long period of time. For an Amp, RMS power rating is the power it can provide for a long period of time. If you drive 300 watts RMS into a speaker rated for 300 watts peak it will blow within seconds. Speaker/subwoofer and Amp should be selected as a pair where the RMS power handling of the speaker/subwoofer should match the RMS power rating of the amp. For a subwoofer, it does not have to be exact, a comparative a rating within 50 watt RMS will be fine. Meaning subwoofer rated at 300 watts RMS will be fine with an Amp rated at 250 or 350 watts RMS.

I went with this Kicker 2 ohm Dual Voice Coil (DVC) subwoofer because I knew I could make it fit in the OEM enclosure. It is rated 150 watts Root Mean Square (RMS), 300 watts peak. Being a DVC means 75 watts per coil. It is hard to find quality subwoofers with a single voice coil (SVC). Subwoofers have DVCs because of flexibility for multiple subwoofer installations and Amp matching. An amp can be wired to a DVC subwoofer with in a parallel or serial fashion. I selected the KICKER 46CXA4001T CXA400.1 400w Mono Class D Car Audio Amplifier Amp because it is rated 150 watts RMS into 4 ohm. I wired DVCs of the Kicker subwoofer serially to present a 4 ohm impedance to the Amp.

Below are photos of the finished modifications to the OEM subwoofer enclosure. Please note the green connector is the OEM subwoofer harness which provides the connection between the OEM amp and the OEM 6x9” subwoofer. I repurposed this harness for the RCA input of the new subwoofer amp.

Stop here go to Part 6: Best Way to Install Kicker 6.75” Sub into the OEM Enclosure

I used a Dremel cutting wheel to make the cuts. I used a file to clean up the shavings. I did make a mistake when fitting the subwoofer. I fitted the subwoofer without the 6x9 to 6.75 inch adapter. This adapter has to be used to install the subwoofer into the OEM enclosure. Without the adapter, I cut too much of the OEM enclosure. I used sound deadening material to cover up the openings I made to the OEM enclosure.

The 6x9 to 6.75” adapter had be tweaked at 8 locations so it would fit flush in the OEM subwoofer enclosure. You can see the silver marks in the picture below. I also had to trim the bend off the top and bottom front of the enclosure (where there are no screws) so the woofer meets flush to the adapter. Look at the above pictures to see the cuts where the subwoofer sits on the cardboard.

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[tmillz1996]

This is one of the better posts I’ve read about replacing the b&o sub. Thank you and congrats!! By the way, how does it sound now?!

 

[Mav_Owner]

From Part 1:

"Conclusion:

The system sounds great. What I thought was a VERY GOOD OEM sound system has been upgraded. The system has improved clarity with uniform and deep bass which emanates from all areas, front and back. The Surround Mode is drastically improved by setting a moderate bias to the rear speakers."

From Part 5:

"The KICKER 48CWRT672 is spec’d to have a frequency response of 30 Hz to 500 Hz. With the 4” rear speakers, the truck needs the added bass from the subwoofer. Being a smaller subwoofer and needing bass from the back of the truck, I set the crossover of the Amp to 200 Hz. If the truck had larger rear speakers I would set the crossover to 80 Hz. To establish the volume of the subwoofer, I first set the input gain of the amp and bass boost to its lowest setting. Next I power on the sound system, play some favorite music, with bass, and set the volume very high, below the point the system clips. Next I increase the input gain on the amp until the subwoofer is too loud. Now I lower the volume of the sound system to a comfortable but still loud volume. I adjusted the input gain of the amp and bass boost to my taste. Surprisingly, the subwoofer bass is not compromised with the seat back up. The bass emanates from rear and not just from the subwoofer location. A couple of days later, after driving with the normal volume, I made, my last, the input gain and bass boost adjustments."

 

[Carlitos_92]

From Part 1:

"Conclusion:

The system sounds great. What I thought was a VERY GOOD OEM sound system has been upgraded. The system has improved clarity with uniform and deep bass which emanates from all areas, front and back. The Surround Mode is drastically improved by setting a moderate bias to the rear speakers."

From Part 5:

"The KICKER 48CWRT672 is spec’d to have a frequency response of 30 Hz to 500 Hz. With the 4” rear speakers, the truck needs the added bass from the subwoofer. Being a smaller subwoofer and needing bass from the back of the truck, I set the crossover of the Amp to 200 Hz. If the truck had larger rear speakers I would set the crossover to 80 Hz. To establish the volume of the subwoofer, I first set the input gain of the amp and bass boost to its lowest setting. Next I power on the sound system, play some favorite music, with bass, and set the volume very high, below the point the system clips. Next I increase the input gain on the amp until the subwoofer is too loud. Now I lower the volume of the sound system to a comfortable but still loud volume. I adjusted the input gain of the amp and bass boost to my taste. Surprisingly, the subwoofer bass is not compromised with the seat back up. The bass emanates from rear and not just from the subwoofer location. A couple of days later, after driving with the normal volume, I made, my last, the input gain and bass boost adjustments."

I like what you've done, but was there a reason you didn't ditch the B&O subwoofer completely and put in a Hideaway HS10? It'd be half the wattage (not that you need 400W for your speaker), but with much lower frequency response.

 

[Mav_Owner]

There were a few reasons

HS10 specs:
- frequency response: 25-120 Hz
- variable low-pass crossover (50-120 Hz)

KICKER 48CWRT672 specs
- 30 Hz to 500 Hz
KICKER 46CXA4001T CXA400 amp
- Electronic Crossover Variable Lo-pass 50Hz–200Hz, 12dB/octave

My set up provides 150 watts of power, RMS, into 4 ohms.

The HS10 does provide a lower frequency response but being a 10" subwoofer its upper end is limited. For the Maverick the rear 4" speakers provide no bass. I selected the KICKER 48CWRT672 and set the amp low pass crossover, at 200 Hz, to provide additional bass, 200Hz to 500Hz. The low pass crossover filter is not a sharp drop but ramps down. If the rear speakers had more bass I would have went a different route, where the subwoofer only provides the most deepest base. The KICKER 48CWRT672 provides deep bass and fills in the bass that a 6.5" speaker provides.

I also did not want to consume the limited under the seat "cargo" space. Being a Hybrid the battery takes up a lot of the little available space.

The B&O subwoofer enclosure ports the bass through the rear, into the body of truck. After hearing it for a few weeks, I feel everyone should take advantage of this set up. The bass emanates from the rear of truck and not just from subwoofer. I believe all Mavericks have the square hole in the rear where the B&O enclosure could be installed. I see B&O subwoofers for sale on ebay. Search for part number, NZ6T-19A067-AB. The enclosure bolts (2-7 mm & 2-10 mm) into the floor of the truck over the square hole.

 

[Carlitos_92]

There were a few reasons

HS10 specs:
- frequency response: 25-120 Hz
- variable low-pass crossover (50-120 Hz)

KICKER 48CWRT672 specs
- 30 Hz to 500 Hz
KICKER 46CXA4001T CXA400 amp
- Electronic Crossover Variable Lo-pass 50Hz–200Hz, 12dB/octave

My set up provides 150 watts RMS of power into 4 ohms.

The HS10 does provide a lower frequency response but being a 10" subwoofer its upper end is limited. For the Maverick the rear 4" speakers provide no bass. I selected the KICKER 48CWRT672 and set the amp low pass crossover, at 200 Hz, to provide additional bass, 200Hz to 500Hz. The low pass crossover filter is not a sharp drop but a ramped drop down. If the rear speakers had more bass I would have went a different route, where the subwoofer only provides the most deepest base. The KICKER 48CWRT672 provides deep bass and fills in the bass that a 6.5" speaker provides.

I did not want to consume the under the seat "cargo" space. Being a Hybrid the battery takes up a lot of the little available space.

The B&O subwoofer enclosure ports the bass through the rear, into the body of truck. After hearing it for a few weeks, I feel everyone should take advantage of this set up. The bass emanates from the rear of truck and not just from subwoofer. I believe all Mavericks have the square hole in the rear where the B&O enclosure could be installed. I see B&O subwoofers for sale on ebay. The enclosure screws into the floor of the truck over the square hole.

Thanks. I'm sure you're aware that bass frequencies are non-directional - meaning, the front door speakers can already do the heavy lifting for mid-bass in the backseat, and in the base stereo, they HAVE to. I swapped out all my speakers as well, and was pleasantly surprised that sitting in the backseat, the door speakers provide the "oomph" back there to make up for the tiny 4" speakers. Anyway, I appreciate your attention to detail and am glad you like your new setup.

I don't have the B&O, so I couldn't follow your lead even if I wanted to - but in my case, I am finding that even DSP, 50Wx4, and all-new speakers don't allow me to get the bass I want unless I'm at really high volume levels... so an HS10 behind the backseat is in my future. Total cash outlay will be a little more than yours all told, but at least I saved some money buying an XLT I guess.

 

[graygoose]

I just got a new 2025 Ford Maverick Lariat Hybrid AWD. I find the B&O system so weak and terrible sounding.

Can I JUST drop in a Kicker HS10, splice into the rear speakers, power and ground at the battery, and not have to add an amp or any other equipment? Literally, just put the HS10 under the seat without opening any panels?

 

[Carlitos_92]

I just got a new 2025 Ford Maverick Lariat Hybrid AWD. I find the B&O system so weak and terrible sounding.

Can I JUST drop in a Kicker HS10, splice into the rear speakers, power and ground at the battery, and not have to add an amp or any other equipment? Literally, just put the HS10 under the seat without opening any panels?

Yes. It has been done:

https://www.mavericktruckclub.com/forum/threads/best-b-o-sub-drop-in-replacement.66913/post-1116581

 

[Ryom]

I just got a new 2025 Ford Maverick Lariat Hybrid AWD. I find the B&O system so weak and terrible sounding.

Can I JUST drop in a Kicker HS10, splice into the rear speakers, power and ground at the battery, and not have to add an amp or any other equipment? Literally, just put the HS10 under the seat without opening any panels?

The B&O actually does what it was designed for well... it's not designed to pound, but have a smooth frequency response overall and it accomplishes that. Adding in a powered box via a sub-level tap (keeping the B&O sub active) should drastically improve the deep bass response of the system.

Better to get a harness that taps into the sub input, the rear outputs have bass cutoff built into the line and will need a DSP to increase the bass level if you tap them. The B&O sub is also frequency limited due to being an infinite baffle enclosure which helps prevents it from bottoming out since there is no air cushion to push back on the driver... but it will be band-passed much lower than the rear inputs are.

https://plugnplaykits.com/collectio...020-ford-f150-with-b-o-plug-play-harness-kits

 

[ryan2366]

The B&O actually does what it was designed for well... it's not designed to pound, but have a smooth frequency response overall and it accomplishes that. Adding in a powered box via a sub-level tap (keeping the B&O sub active) should drastically improve the deep bass response of the system.

Better to get a harness that taps into the sub input, the rear outputs have bass cutoff built into the line and will need a DSP to increase the bass level if you tap them. The B&O sub is also frequency limited due to being an infinite baffle enclosure which helps prevents it from bottoming out since there is no air cushion to push back on the driver... but it will be band-passed much lower than the rear inputs are.

https://plugnplaykits.com/collectio...020-ford-f150-with-b-o-plug-play-harness-kits

Nice write up. I’ve done an almost identical setup to you minus the centre channel and rear setup. Looking to give it the needed help you accomplished.

I’ve been to the link you suggested before and wasn’t sure exactly what harness I would need to order.

I have the same kicker sub and setup as you but also wanted to power the upgraded rears and sub the same way.

What harness did you purchase to accomplish your setup?

 

[Ryom]

Nice write up. I’ve done an almost identical setup to you minus the centre channel and rear setup. Looking to give it the needed help you accomplished.

I’ve been to the link you suggested before and wasn’t sure exactly what harness I would need to order.

I have the same kicker sub and setup as you but also wanted to power the upgraded rears and sub the same way.

What harness did you purchase to accomplish your setup?

I'm not the OP, just an interested 3rd party who did some experiments with upgrading the B&O sub a little while ago

There is an email address ([email protected]) on that page you can use to contact the owner whom I'm sure will talk you through what you need.

 

[ryan2366]

Ahhh got it. Get lost in these threads sometimes. Thanks

 

[pasando]

This is all great information. Thanks to everyone for taking the time to post all the details

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