Another Sub woofer & Amp Installation

[hand-filer]

First off, I have to thank nate.co and his excellent thread Mega audio upgrade -- sound deadening, speakers, stealthbox sub, GMRS radio for guidance. The information was invaluable and a major time saver.
I went with the following components:
Hertz MPS 250 S2 shallow subwoofer
Hertz DIECI POWER DP 1.500 Mono Class-D Amplifier
Stealthtech Sub Enclosure
Kicker Keylok & Harness

I used 6061 T6 Aluminum 2'' x 1/8'' Flat Bar for the mounting brackets.
Tools used to fabricate the brackets:
-hack-saw
-assorted hand files
-1/2" disk sander
-6" bench vise

The factory sub is a 5 1/2" driver in a tuned wave enclosure. It operates in a very narrow frequency range. It sounds hideous and does more harm than good if you leave it connected.
My advice to anyone contemplating a similar upgrade is to shit can it and utilize the space to mount your amp.
I too had to reduce the gain on the KeyLok as it is pre-set way too high.
Overall I'm very happy with the outcome. I didn't bother upgrading the rest of the speakers. They sound pretty good once you remove the factory sub and add a real one.
Here are some images of what I concocted for bracketry and the end results:

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[BrrRaptor]

Why the need for a separate amp? Can't you just take the wires from the factory sub and put them on new sub?

 

[pablo94sc]

No. It's a low powered amp with something like 50w for the sub. You need quite a bit more power to properly drive a sub in a small enclosure.

 

[maus92]

One of my complaints about the factory B&O system is the front to back balance - the front is way too weighted even when fading all the way to the rear speakers. How is this imbalance addressed?

 

[pablo94sc]

One of my complaints about the factory B&O system is the front to back balance - the front is way too weighted even when fading all the way to the rear speakers. How is this imbalance addressed?

Simple answer - The sound stage is supposed to be in front of you. The rear speakers are meant for fill, to help add some volume and depth to the midrange. Think theater, not nightclub.

Longer answer from another forum -

https://www.f150forum.com/f30/realities-rear-fill-why-you-should-save-your-money-445164/

Either way, you address by spending thousands of dollars. I personally have always moved my sound stage forward in my cars.

 

[maus92]

Yea, I still hate it - I like the immersiveness (I realize it is not a word lol) of quasi-surround sound.

 

[hand-filer]

After living with this setup for about 10 days now, I can honestly say I'm still amazed by how this has improved on the B&O system.
The key to making it work is:
1-removing the distortion inducing mediocre factory sub.
2-using the Kicker Keylok and harness from Sounds Good Audio to integrate the components.

 

[DaStockRR]

After living with this setup for about 10 days now, I can honestly say I'm still amazed by how this has improved on the B&O system.
The key to making it work is:
1-removing the distortion inducing mediocre factory sub.
2-using the Kicker Keylok and harness from Sounds Good Audio to integrate the components.

I have a Sounds Good Harness w/ KeyLoc, JL Stealthbox, and Audio Control 1.300 ready to install.

 

[mattcarson]

Can you let me know exactly what harness you bought? Also, did you have to run power direct from the battery to power the amp? Thanks.

 

[hand-filer]

Can you let me know exactly what harness you bought? Also, did you have to run power direct from the battery to power the amp? Thanks.

The information on the harness and Keylok is provided in the the original post.
Yes, a dedicated power wire from the battery to the amp is required.

 

[Canoman]

The information on the harness and Keylok is provided in the the original post.
Yes, a dedicated power wire from the battery to the amp is required.

The link to Sounds Good Stereo in the original post to the harness & Keylok takes me to a 404 error page, as of 6/10/2025, 2:50pm CST.

Is this the same setup? Factory Connection Harness to add a new Subwoofer Amplifier while retaining factory B&O including Unleashed

 

[hand-filer]

The link to Sounds Good Stereo in the original post to the harness & Keylok takes me to a 404 error page, as of 6/10/2025, 2:50pm CST.

Is this the same setup? Factory Connection Harness to add a new Subwoofer Amplifier while retaining factory B&O including Unleashed

That's the one.

 

[Buellsox]

That's the one.

Sorry for jumping on this thread late, really hoping “hand-filer” will come back across this…..I’m in the beginning phases of gathering all the pieces for a partial interior gut this spring (sound deadening, cable routing, etc.) and your thread has got me thinking. Considered the only solid choice was to go with the JL Audio pre-fabbed 10” enclosure that’s $1,200 bucks and always seems to be on back order.

But now that Aussie made box and running something like that Hertz 10” (which handles more power instead of dancing right off the 300W threshold which is the case with the JLA) seems like a better setup and will be hundreds less.
So my questions to you are if you don’t mind taking a minute…..what are you thoughts of the setup? Does it clear the seat bottom? Roughly remember the total cost to get that box here (or Canada in your instance) with shipping? Was it worth it? How does it stay put in the storage tub location?
And lastly (my apologies for all this) but do you have any pics of the install wiring setup from the Keyloc to the amp? Did you run a dedicated RTO line back to the dash or use utilize the Kicker cheater box that pulses the signal to turn the amp on and dismiss the separate RTO line?

It’s been since the late 80’s-late 90’s when I messed with car stereo and it was so much simpler then. Any pics of the wiring between the Keyloc & amp would be greatly appreciated! I’m definitely going the route of the SGS harness. Seems like a no brainer. Just want to make sure I capturing it all.

Great install BTW! Might be mimicking that setup if I get good feedback on that Hertz 10”!
Thanks a ton!

 

[hand-filer]

Sorry for jumping on this thread late, really hoping “hand-filer” will come back across this…..I’m in the beginning phases of gathering all the pieces for a partial interior gut this spring (sound deadening, cable routing, etc.) and your thread has got me thinking. Considered the only solid choice was to go with the JL Audio pre-fabbed 10” enclosure that’s $1,200 bucks and always seems to be on back order.

But now that Aussie made box and running something like that Hertz 10” (which handles more power instead of dancing right off the 300W threshold which is the case with the JLA) seems like a better setup and will be hundreds less.
So my questions to you are if you don’t mind taking a minute…..what are you thoughts of the setup? Does it clear the seat bottom? Roughly remember the total cost to get that box here (or Canada in your instance) with shipping? Was it worth it? How does it stay put in the storage tub location?
And lastly (my apologies for all this) but do you have any pics of the install wiring setup from the Keyloc to the amp? Did you run a dedicated RTO line back to the dash or use utilize the Kicker cheater box that pulses the signal to turn the amp on and dismiss the separate RTO line?

It’s been since the late 80’s-late 90’s when I messed with car stereo and it was so much simpler then. Any pics of the wiring between the Keyloc & amp would be greatly appreciated! I’m definitely going the route of the SGS harness. Seems like a no brainer. Just want to make sure I capturing it all.

Great install BTW! Might be mimicking that setup if I get good feedback on that Hertz 10”!
Thanks a ton!

I'm super pleased with results. The Amp and sub are an excellent match. I used JL Audio components in my last build way back in 2010. I would not hesitate to use Hertz components again and highly recommend them. This sub moves plenty of air for a shallow design, it pounds!

Total cost for the sub box was $245 CDN delivered. Shipping was $79 CDN. The box has since gone up in price by around $30. Keep in mind there's a trump tax on goods from Australia now.
The sub box is nice and snug. The seat touches the grill but does not put any pressure on it.
I did run a separate RTO line to the fuse panel.

If you do go this route you will need to turn the gain down on the Keyloc. It was set way too high for the Hertz Amp.

Sorry I won't be able to provide images of the wiring. Everything is tucked away now. What I can say is, it's super straightforward to wire up.

If I had to do it over again, I wouldn't deviate from this setup. I really like it.
I hope this helps your decision making process.

 

[Buellsox]

Great Stuff! & thanks for responding back. Really helped make up my mind. I just pulled the trigger on the SGS Keyloc kit so it’ll wire in super easy. Could go cheaper separately, but that loom looks super clean & it’s already done. I like clean & easy.

Believe it or not I’ve been sitting on a factory sealed RF Punch 300 since 2007 (a domestic made in USA model not overseas) that I think is finally going to see the light of day on this build. Only bugaboo is it’s going to require a 4G power lead & big fuse blocks, but it’ll tuck under the carpet. At least start it out that way since I have it and see what I think. It should pound a 10” in a small enclosure all day long. Those old RF Punch amps were a mess top choice back in the day.

Really leaning towards that Hertz shallow 10”. Lot of good reviews on that sub and you say you do it all over again with that component, so I’m sold.

Couple more ?’s if you don’t mind…..
How stable/locked in does that box stay in the storage tub location and where might I ask did you land back to for your remote turn on?
Thanks again!

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