Stealth DSP-Tuned Audio Upgrade with Before/After RTA

[snowkarver]

Ok.. I never hooked up amps to a factory radio so I’m learning as I go lol.. I really wanted to do the loopback harness like you got from plugnplaykits but not sure if I can do that with having the crossovers. I know some people mount the crossovers right next to the amps but I’m not sure how they wire them up. I know there’s a company LLJ customs makes some type of loopback harness that has a crossover option that just has extra wiring for the crossover but I’m not sure how that works.

You can still do the PNP loopback with a passive if you don’t mind a bit of modification - I found it to be of quite good quality.

I would cut the front LR speaker signal coming back from the amp at the head unit (he uses a molex connector here making this quite easy) and redirect this to crossovers mounted behind the glove box. Then wire the woofer outs from that back to where you clipped the harness, sending it back into the stock wiring to the doors. Then new wires from the crossovers up to the tweets.

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[Ducky2022]

Very cool information! I got similar measurements as yours. Didn’t see any bass roll off with volume either. Interested to see how well you can EQ your system.

I used a fix82 to flatten the signal before going to the JL VX1000i DSP (to make it easier to tune). Only had 10 bands of eq to work with per channel. But their autoEQ function helped a lot.

 

[snowkarver]

Spent a lot of time over the past couple of weeks installing and tuning. Most of the techniques have already been posted and are well worn by now, and they work well, although I did pick up a few lessons learned along the way!

Equipment rack behind rear seat

Test fit on cardboard - there's just enough room for a Kicker HS10 and a small Class D amp. This is an Audison Prima AP8.9, which is a 9-channel PC-configurable DSP with 35W x 8 channels of clean power. Any pair can be bridged to drive 130W at 4 ohms, which is what is going to the door woofers. Dash tweeters and rear fills get 35W each. Each of the six speakers is independently controlled by the DSP and gets its own amp channel.

The board itself is 5/8" MDF with a layer of automotive carpet upholstered on the front, and a layer of Kilmat 80 mil on the back.

Everything is directly mounted to the rear wall with elevator bolts epoxied with JB Weld. Below was my first attempt with minimal sanding of the paint and using Kwik Weld - it did not go well, and they snapped right off from the torque of tightening the board. With take two, I sanded down to bare metal, and used conventional JB with a clamping rig for 24 hours, and it's solid.

Important note - if you are mounting a sub to the rear wall, the sheet metal is a weak point for resonance and it will vibrate badly. This is especially critical if you have a sliding window, as that will rattle even worse. Use butyl on everything back here, and dense mineral wool in the cavities - this is one place where deadening really makes a difference. I also have rubber isolation mounts between the board and Kilmat for a little extra decoupling.

Finished equipment rack with wires and cables in place for fitting. The turquoise bundle at the amp input is a pair of AudioControl AC-LGD load generating filters which simulate a 4 ohm speaker load so the head unit behaves properly at all times, and also stabilizes the high-level signal going into the Audison.

Power Run

I made a custom set of 4AWG cables with some nice automotive wrap and a 120A ANL master fuse.

The grommet in the firewall above the brake pedal where you run the line is a critical part! While building this harness, I drove for a day without it in place - and it is loud. It literally sounds like the fuel injectors are ticking inside the cabin. Once I discovered this, I didn't want to just drill a hole and shove the cable through. I got a locking 4 gauge bushing that clamps to the grommet and seals tightly around the cable. Didn't want to mess with any unnecessary sound leakage from the sewing machine up front.

Nice factory cable conduit at the rear door sill.

And another one at the driver door. There is ample room for a big power cable, but the Plug N Play signal harness has two 9-conductor speedwires that just barely fit through this sill on the passenger side.

Finished power harness at the battery. I mounted the all the way back against the firewall to make room for the Steeda strut tower brace I bought, but hasn't arrived yet.

 

[snowkarver]

Very cool information! I got similar measurements as yours. Didn’t see any bass roll off with volume either. Interested to see how well you can EQ your system.

I used a fix82 to flatten the signal before going to the JL VX1000i DSP (to make it easier to tune). Only had 10 bands of eq to work with per channel. But their autoEQ function helped a lot.

Thanks!

That's a great solution. The Audison DSPs have a de-equalizer built in into their first stage to do the same thing - you send it pink noise and it flattens out the signal internally. Agree that it's a pretty important step to make EQ easier.

 

[snowkarver]

Tweeters next.

As others have experienced, these were a pain to install when compared to some of the drop-in options from Focal or Powerbass, as they required some serious dash butchery. But I really wanted Morels for this build.

Luckily, I discovered that the flush mount they include in the box fits nicely in the factory opening if you remove all of the plastic used to clamp the stock tweeters. It took a 60W hot knife and most of an afternoon, but I was thrilled when my new mounts dropped in perfectly, and I am very satisfied with the result.

No one will ever really see this, but since I literally stare at the dash every day, I'm happy to know it was done right!

Removing the stock tweeter:

Morel tweeter flush mount, in the happiest test fit ever:

Cables pulled. I ran a new pair of 2x 16AWG cables all the way from the amp behind the rear seat as each speaker is actively driven with no passive crossovers. The original factory tweeter wiring is deadheaded in this bundle.

Tweeters installed. The mounting bracket has a perfect friction fit, so just a couple dabs of cyanoacrylate super glue to lock everything down, and the end result looks so nice I wish I could do some kind of custom removable grille.

 

[snowkarver]

Rear Speakers

The C-pillar trim is a pain to remove. Even though I knew the tricks and used a trim lever to push upwards on the panel clips, I still managed to rip one off. It's not a great design - even the smallest bit of sideways torque when pulling will probably do damage to the back of the panel.

The rear pillar speakers will never really be driven hard since they're like 6 inches away from the passenger's ears, but still, you can see the thought Ford put into these 75 cent drivers. Here they are next to the Kicker KS 4" that replaced them.

Broken trim clip plastic. JB Weld is your friend!

Drop-in replacement, and a little mini adapter from Plug N Play kits to connect it back to the factory harness without splicing.

 

[snowkarver]

Door Woofers

Pretty straightforward install here. The stock 6.5" drivers have probably the smallest magnet and voice coil I have ever seen in a speaker of this size! It's actually amazing the output they produce when you look at their business end.

Here they are next to the Morel Tempo Ultra Mark II woofers.

Door card off. It's pretty standard construction with easy trim removal.

Kilmat on the inside of the outer skin was probably the toughest part. Important lesson - for some reason, it did not occur to me that this vertical brace was actually the window track, as the design is different from other vehicles I have worked on. I had to trim it a little to fit the Morel's oversized magnet, but not enough to affect the structural integrity.

On the other hand, do not under any circumstances let sticky butyl foil get on the backside of this track. Ask me how I know, and what the window servo sounds like when it runs into a sticky mess. Luckily, it cleaned up with a scraper, some Goo Gone, and a nice coat of silicone grease.

New woofer in place with a thick ring of high-density foam which seals it up to the door card, plus a first layer of Kilmat 80 on the inner skins.

When everything is buttoned up, the slam is drastically different on the front doors versus the untreated rear doors. It sounds like a different vehicle, to the point where I might consider doing those as well, just for consistency.

Everything is now installed and I have begun the testing process. Early results are looking pretty good, stay tuned!

 

[snowkarver]

Final Results

Here's the frequency curve after two rounds of EQ. Red is stock, green is the current response, and the dotted line is my target curve, which is the JBL/Audiofrog standard for car audio.

Even with mid-level equipment, the Maverick cleans up quite nicely, on par with other economy vehicles. The three most noticeable changes are:

• The huge contribution that even a small packaged sub like the Kicker HS10 adds to the low end. Being able to EQ it via DSP provides the fine control needed to manage its limited 180W amp, but when done right, you can see that it ramps up very nicely right from its subsonic filter at 25Hz, hits 0dB at 33Hz, and then holds this cleanly right to the low pass at 80Hz. It's not going to win any IASCA competitions, but it's smooth and puts out about as much energy as I would want in the Maverick cabin (see listening notes).
• Pushing down the low mids from 200-800Hz removed a lot of boxiness from vocals and instruments. With better, more controlled speakers, it's no longer necessary to boost vocals and speech for clarity, so reducing the energy here removes the "megaphone" effect where human voices sound like they're being forced through a toilet roll.
• Bringing up the presence range immediately added dimensionality back to music. Killing the 4500Hz dip instantly created a soundstage between the dash and windshield - not a great one, but way better than being able to hear sound independently coming from four separate drivers, which I could do with the stock system.

Listening Notes

Bass - The Maverick is leaky, so sound pressure goes out, and road noise comes in, very easily. Even with the low end set correctly in the parking lot with engine off, once you start driving, a lot of low frequency energy disappears or is mixed with rumble, throwing off the perceived acoustic balance. The engine sound enhancement that Ford adds to many of the driving modes doesn't help either. After additional testing, I boosted the sub with an additional 5dB of gain to bring the 30-80Hz range up to +15dB, and it was much better. One last note here is that, for me, this is about the maximum bass energy I'd want in my Maverick. In terms of trim fitment, it's a pretty low quality vehicle, so even with this very modest amount of power, things are beginning to shake and vibrate, most noticeably in the rear wall and especially the rear sliding window.

Treble - As I expected, the vast expanse of hard plastic up front and tweeters positioned to reflect off the glass are not optimal for the high end. Although my RTA readings were perfectly lined up with the JBL curve above 5KHz, I found any music with a high frequency bias/mix to be extremely fatiguing after just a few minutes. The complex reflections with no absorbent surfaces just do a number on the high end. After experimenting with different roll-offs, the best solution I found was to reduce the energy going to the tweeters -3dB by trimming those channels in the DSP. It's not exactly a best practice, but the Maverick isn't exactly the best canvas. Lowering the tweeter volumes relative to the rest of the mix took a lot of the harshness away, without losing the sparkle and sheen that would happen if you just rolled off the high end more sharply.

Overall, this has been a worthwhile project. It's only been tuned for a day, so I'll have to listen some more and see if anything else crops up.

 

[colinl]

I'm so glad you shared this info, notes and your overall knowledge. I have not used the software you're using. I've never even used a real carfi dsp, just a parametric eq and what experimenting with what sounds best. I have an inexpensive Dayton iMM6 mic and audiotool, and I was just looking to see what I can learn, and maybe make a few tweaks.

I guess my first question is, when you've boosted the low end of your Kicker HS10 that much, how much SPL can it produce before it overextends? I see your tuning RTA is showing 85 dB SPL. To me, that's pretty low, especially given the Audison amp you're using, I bet your front speakers can drive over 100 dB fairly easily. What's the HS10 doing when/if you turn it up that loud? Granted, most music is going to have bass notes in the 40-60hz range, which it'll handle a lot more easily.

 

[snowkarver]

I'm so glad you shared this info, notes and your overall knowledge. I have not used the software you're using. I've never even used a real carfi dsp, just a parametric eq and what experimenting with what sounds best. I have an inexpensive Dayton iMM6 mic and audiotool, and I was just looking to see what I can learn, and maybe make a few tweaks.

I guess my first question is, when you've boosted the low end of your Kicker HS10 that much, how much SPL can it produce before it overextends? I see your tuning RTA is showing 85 dB SPL. To me, that's pretty low, especially given the Audison amp you're using, I bet your front speakers can drive over 100 dB fairly easily. What's the HS10 doing when/if you turn it up that loud? Granted, most music is going to have bass notes in the 40-60hz range, which it'll handle a lot more easily.

I'll take a SPL meter with me next time I drive and test. The FR curve shows the sub at 85 dB SPL because the reference test standard for response is to have your sweep tones (generated at -18dB) set at 75dB in the room to get the best representation of response at "normal" listening volume.

 

[billbillw]

Nice job! I had no idea that Ford had that much DSP/EQ on the signal. Holy crap! My old days in car audio (80s-90s and last install was 2010 in a MS3), the head units had relatively flat outputs and we adjusted crossover points and levels to make it work. I never messed with DSP other than on my Home Theater setup.

I might be DM'ing you for advice. I want to make some changes to my Lariat (non-Sync), but I'm looking to stay in a lower budget. I am pretty sold on the Kicker HS10 though.

Wasn't there some ebay DSP that was substantially less expensive than your Audison? I thought I saw it in some older thread. I wish MTC would create an audio only sub-thread.

I'm probably going to leave the rear speakers alone and leave them faded almost off. I don't need much rear fill. Any recommendations for a 6.5 component set in the $200 range?

 

[snowkarver]

Nice job! I had no idea that Ford had that much DSP/EQ on the signal. Holy crap! My old days in car audio (80s-90s and last install was 2010 in a MS3), the head units had relatively flat outputs and we adjusted crossover points and levels to make it work. I never messed with DSP other than on my Home Theater setup.

I might be DM'ing you for advice. I want to make some changes to my Lariat (non-Sync), but I'm looking to stay in a lower budget. I am pretty sold on the Kicker HS10 though.

Wasn't there some ebay DSP that was substantially less expensive than your Audison? I thought I saw it in some older thread. I wish MTC would create an audio only sub-thread.

I'm probably going to leave the rear speakers alone and leave them faded almost off. I don't need much rear fill. Any recommendations for a 6.5 component set in the $200 range?

Thanks. Yeah, digital domain processing has really advanced in the last couple decades to the point where it makes a significant improvement even at the lowest price points.

I really think the HS10 makes for easiest, most compact install if you're not looking for maximum low-end extension and SPL.

I believe the off-brand DSP folks were talking about is the Puzu - don't have any experience at all with this, but it probably works pretty well. If you don't want to mess around with PC configuration of the DSP, the Kicker Key is a great piece that I use in my XC60 build - it uses an automated tuning sequence that does a pretty decent job in 5 minutes.

For $200 component sets, there are lots of choices - pretty much anything blows the factory drivers out of the water. Focal ASE series, Kicker KS series, Morel Maximo/Maximus on sale - all good. I know some folks here had a good experience with some of the Powerbass OEM replacement stuff - not as familiar with them though. Depends on how much tinkering you want to do with the install.

 

[billbillw]

Thanks. Yeah, digital domain processing has really advanced in the last couple decades to the point where it makes a significant improvement even at the lowest price points.

I really think the HS10 makes for easiest, most compact install if you're not looking for maximum low-end extension and SPL.

I believe the off-brand DSP folks were talking about is the Puzu - don't have any experience at all with this, but it probably works pretty well. If you don't want to mess around with PC configuration of the DSP, the Kicker Key is a great piece that I use in my XC60 build - it uses an automated tuning sequence that does a pretty decent job in 5 minutes.

For $200 component sets, there are lots of choices - pretty much anything blows the factory drivers out of the water. Focal ASE series, Kicker KS series, Morel Maximo/Maximus on sale - all good. I know some folks here had a good experience with some of the Powerbass OEM replacement stuff - not as familiar with them though. Depends on how much tinkering you want to do with the install.

I thought about the Powerbass, but I saw some scary reviews where the surround glue gave up after two years.

Also thought about the Focal Inside drop in components (at a reduced price from a certain seller) and the Key 200.4, but the Key seems to be sold out everywhere.

Does the Key work in a front stage with sub woofer configuration? 4 channels for tweeter and mids and RCA output for the sub? I have yet to dive into the configuration options.

 

[snowkarver]

I thought about the Powerbass, but I saw some scary reviews where the surround glue gave up after two years.

Also thought about the Focal Inside drop in components (at a reduced price from a certain seller) and the Key 200.4, but the Key seems to be sold out everywhere.

Does the Key work in a front stage with sub woofer configuration? 4 channels for tweeter and mids and RCA output for the sub? I have yet to dive into the configuration options.

The Focal IS Ford would be a good choice to avoid messing with the tweet mounts.

If you’re not touching the rears, the Key if you can find one would be great as it can be set to bi-amp a 2-way front. It won’t actively DSP the sub though, so you’d be intercepting the fronts and using the internal low-pass crossover on the HS10 to blend in the sub-80 Hz stuff.

 

[billbillw]

The Focal IS Ford would be a good choice to avoid messing with the tweet mounts.

If you’re not touching the rears, the Key if you can find one would be great as it can be set to bi-amp a 2-way front. It won’t actively DSP the sub though, so you’d be intercepting the fronts and using the internal low-pass crossover on the HS10 to blend in the sub-80 Hz stuff.

I'm thinking in that configuration, it would require separate wires to be run up into the dash for the tweeters. Also, I'd have to put a capacitor on the 6.5" to give a 6db high pass around 80Hz and make sure I tapped the subwoofer before that...

Lots to think about. I'm looking at the Puzu also, but I found at least one person who had issues with that amp loosing a channel after a year or so.

I swore I would never do another install after my Mazdaspeed3 install. Since then, I've had livable stock stereos up until the Mav. I won't be doing anywhere near that kind of install though.

On the MS3, I took out the entire rear interior to cover everything in Raamat and ensolite (which was a cheap way of doing it at the time). I also drilled out and fished two pairs of wires through the molex connectors into the doors for a pair of PPI 356cs. A Dayton Reference 10" sub in a .7cu ft box all powered by an Audison SRx3. It was pretty good for a stealth, non DSP'd system. I took the main components out, but left the LOC and wiring before I traded that in. I left a note in the owner's manual that the car was pre-wired for an aftermarket system and that it had sound dampening everywhere. Probably never got utilized, but who knows...

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