Amps

 

Rear dash.
3/4" pine plywood for 5x7-to-6x9 adapter ring

Adapter to OEM wiring

 

Door speakers: 5x7-to-6.5" adapter rings. OEM connectors, quick-disconnect pigtails in prep to run full wiring through OEM door port

 

Subwoofer and Small Box pt1

Sub: Diamond Audio TDX10d4
Box: ~0.8ft³

 

Sub and Small Box pt2

Internal bracing, gussets and doubling the front baffle for the ~20lb sub that has an 800w rms rating

Finished

 

Wiring the sub

My standard wiring practice for my subs are to wire them in parallel (+/+, -/-) because i usually have a sub that is able to handle more power than my amps put out.
2ohm

4ohm

Overkill (aka "future-proofing") is common practice in my personal builds
The blue/silver wire is 8ga and the black is 10ga

 

Airvent Tweeter install
(This took a while to get to. I didn't finish this install until until i ran the speaker wiring, but this is the process)

2.5" pvc pipe coupler and 3" rubber pipe cap

2.5" threaded internal pipe plugs into the feeder pipes from the air vent distribution box thing (behind the center console). Used an oscillating cutter to fit in there and cut the tubes

 

Amp wall/trunk-cabin divider

2 sheets of 3/4" MDF glued together for a 1 1/2" thickness because i want to reduce as much vibration transmission to the amps as possible. More future-proofing that will make sense further on in the build log.

Cardboard template because wood is expensive. Bottom cutout is for the wireloom that runs along the floor into the trunk from the driver side. Top corner cutouts are to clear the opening's corner ridges. I could have made this in 2 pieces and lap-joined them in the center....but i was on a roll and didn't think of it until everything was glued, cut and about to be installed

-Not shown- all the fitment trimming to get that final shape...in...out...in...out...in...out


Wall

 

New floor. More 3/4" MDF.
Traced the carpet and the spare tire cover, then cut into 3 pieces to ease install and accessing the spare

 

Riveted/screwed the wall to mount it.
Cabin side

Trunk side mounts are visible in the last pic

Shelf to cover the down slope from the rear axle hump to trunk floor

leveling the shelf and making the supports

Finished installation in the trunk. Laid the carpet.

 

Wiring time ya'll! Yay!

Knukonceptz kolossus 1/0ga (reality is 2/0) power and ground wires.

Just some teeny wires 😆

Positive distribution block and (for now) negative distro block. It ain't pretty, but it's possible, solid and in my defense, not what i ordered.

 

Alright, now for the nitty-gritty.

Because of the design for my battery block, I needed to modify the OEM clamp and extend the primary Pos for the car systems.
I used YC Industries tape for the final wrap, some people swear by Tesa tape and shun all others....it worked fine for me and is still holding strong, so who knows

Cut down the clamp then drilled a hole in the flat area so i can bolt it to the new terminal block. Prepped a length of 4ga wire (always OFC) heat shrunk one end at the lug/wire connection and left the other alone

Bolted the two connectors together (VERY tightly)

The heat shrink has glue inside to insure against it coming loose and the white loom is Techflex F6 because it has a high heat rating.

 

Power wire shenanigans

Only took 2 hours of back and forth measuring to drill that feeler hole

On to the big stuff
This is a waterproof grommet, used for exterior junction boxes

You can see the techflex in the bottom of the picture

 

RCA time aka tear-the-dash-apart. This is when i installed the plugs into the vent piping and the driver side tweeter. I have a little blue box in the radio area - ignore it - it's a scosche slc-4 line out converter that i thought i would need so i put it in when i installed the JVC radio, but ended up not needing so i took it out. The head unit (HU) has rca outputs for front, rear and subwoofer.
Apologies for the sideways pics

If you ever wondered why you would need a 1/4" drive, 18" extension...here:
Taking out the dash gauges

More techflex for abrasion protection

Under the dash area

Behind the driver seat

 

Now for the actual fun part: gear install

brackets to hold in the sub box

amps

In the upper left of the middle pic are the mounting screws for the amps. As a further protection from vibration, those are o-rings and rubber washers to put between the amps and the wall

Positive distro block/crossover plate. The Soundstream rn4.1400d is a 4 channel amp, problem is that i have 6 channels. Solution, use crossovers to split the front signal for the tweeter and midrange. These are also Bi-Amped (2 inputs) so i bridged the single input wires to the 2 inputs.


Crossovers: Focal ES165K2

 

Getting everything installed

Running speaker wire. Label everything!!!!

Gone fishin'
Pulled the speaker wire behind the center console in order to run it to the passenger side tweeter/midrange.

 

Remade the brackets to replace the OEM brackets. The adapters push the midranges too far out and into the door panel. Cut the mounting tabs off the OEM speaker brackets and used them to mount the new brackets to the door. Used rubber weatherseal to seal everything up between the bracket and the door metal. Rubber weather stripping to seal the speaker against the door panel in a good way and closed cell foam cups for the back of the speakers.

I don't have any pictures of the 5 hours it took to figure out how to run speaker wire through the molex clip in the door jam. Ended up running 18ga jumper through the molex and soldering the 10ga to make the 18ga as short as possible.

 

Rear seat bottom cushions installed. I ran the power wire through the passenger side seat belt hole because why not? I think it looks kinda cool, too.
At this point, literally the only thing to do is put the Main (underhood) fuse in. I was super nervous because this is, honestly, the most complex and time consuming personal project I've done.

I had to take a break and just stare at it for a while (after I hooked up the loose wires of course).

It wasn't "beautiful", per se, but it was the culmination of 19 months of planning, designing, research and gear acquisition...it was a slightly emotional moment 🤣

Full gear list at this point -
JVC-KW350BT
SoundStream RN4.1400D
Kenwood Excelon XR600.1
Focal ES165KX2 passive crossovers
db Audio PRO6K components
Kicker KS693
Diamond Audio TDX10D4
Knukonceptz Kolossus 1/0 power/ground
db Link 10ga speaker wire
Metra rca's
db Link main fuse block (100A)
Recoil BBPG5 busbar (bridged)
Shuriken busbar
Raptor inline MANL fuse holders to amps (80A to Soundstream, 50A to Kenwood)

 

Crackhead camo, held on by dismantled speaker magnets. $3 at walmart

Numquam Complevit

Fair warning, the following has caused quite a few people's eyes to glaze over when they ask "What are you doing?"
This is the part that customers don't see when they have an installer do a system in their car. Enjoy and feel free to ask questions.

Gain Setting.

As much as the Youtube Experts say you can, you can't just slap in an amp, crank the gain knob and call it done.

No, don't do it. You WILL make your sub/speakers release the magic smoke that allows them to make music.

All you need is a few test tones (sonicelectronix has a bunch on their youtube channel) and an oscilliscope. I got mine on Amazon for ~$40.

The purpose is to set the power levels on the amp to prevent "clipping" from over-amplification of the source signal. A clipped signal will have plateaus on the high/low points on the wave whereas a good signal will a beautiful sinewave.
The trick is to get it as close to clipping, without actually clipping.

Tones: I only really need two for the Soundstream, 1.5khz and 100hz. For the Kenwood amp, I used multiple frequncies to get a feel for where the amp like to boost its signal.
I didn't take any pictures of me scoping the Soundstream because, honestly, it was pretty straight-forward. Sorry. My gain set for it was:
(watt's law: Volts^2 / Ohms = Watts)
Front: 1.5khz for 16.1Vac 16.1^2 / 4= 64.8w
Rear: 100hz for 18.8Vac 18.8^2 / 4= 88.36w

Sub:
I confess that i cannot find the pics for this. All I can find is that i had it set for around 33.5Vac for 561.13w to the sub...Sorry. I do have the documentation for the amp I replaced the Kenwood with, if you could scroll to post# 23



This head unit has the ability to be a (limited) Digital Signal Processor (DSP) and control the frequency split to the signal outputs:
Front: Tweeter and Midrange
Rear: Midbass
Sub: Subwoofer

Here are the screens

Each output can be modified to control the signal level (gain), cutoff frequency (low pass/high pass) and how "quickly" the signal is affected by the cutoff (6, 12, 18, 24db slopes).
This is necessary for balance.
There are 3 main styles of audio setups
SPL: sound pressure, loud
Think competition vehicles with 10 subs or the youtube videos with women's hair dancing in the window...or that Suburban that is shaking your car at stoplights

SQL: sound quality, loud
My goal. The system has the capability to get very loud, but it is still very clear with no distortion and the musical balance is maintained throughout the volume levels. Sonic purity, if you will.

SQ: sound quality
Like SQL but not loud. Usual power rating is around 50w per speaker channel and maybe 300-400w to the subwoofer. Really not a lot of power.

This is where Tuning comes into play. The DSP in my HU is very, very basic, but it allows me to balance quite well actually and has surprised a few folks who have waaaay more money invested in their systems than I do right now.

Aside from gain setting and doing a basic cutoff setup (see pics), this was where I left my system for a few months. I did play with the equalizer settings to get a feel for different settings, but that was about it

 

I got bored and decided to see what all this talk was about Midbasses, so I clipped some wires on my Kicker KS693's. Wrong wires. I thought I had killed the 6x9's so i went and looked for some cheap replacements.
Behold, the Kicker RT67. Too small of a sub to actually BE a sub, but not built to play midrange frequencies.
Fabricated some brackets out of some scrap MDF to replace the 5x7-to-6x9 brackets.
Dual 4ohm voice coil, 150w rms, frequency range: 30hz-500hz
Perfect for a bridge between the midrange (what you think of when you hear "speaker") and the subwoofer

Wired them parallel for 2ohm impedance to take advantage of the power capabilities of the Soundstream amp.

 

Around this time I acquired a beauty of a sub: the Adire 12KH501d2. I also built a different box for it because the box for the Diamond sub was too small...and for a 10" sub, not a 12".

I decided this would be a perfect time to swap out the Kenwood amp with a Mercury Audio C800 as well.

Fitting the new power/ground wires. New amp, new wires.

Adire sub and box. I used 3/4" Birch plywood, double top baffle. 1.32cuft (gross).

Ran new wiring for the midbasses in the rear deck, new (matching, I have a touch of OCD even with what can't be seen) RCA's and insulated the rear dash using pipe insulation "tape" on the high spots to prevent rattling.

 

Gain setting the Mercury amp.
These are the o-scope readings, you can see the frequencies in the bottom right of the scope's screen. This amp has a subsonic filter which is basically a high pass filter - it cuts off frequencies below a set point. The Mercury's cutoff is around 15hz because the sub's excursion (how high the voice coil can rise in its channel without jumping out and causing damage) limit would be dangerously exceeded at frequencies lower than that.

With this knowledge and with the sub's voice coils wired parallel for 1ohm, we can do the following math to determine the wattage going to the sub.
Remember Watt's Law: V^2 / Ohm = Watt
20hz 24.3^2 = 590.49w
30hz 32.8^2 = 1,075.84w
40hz 31.8^2 = 1,011.24w
50hz 29.3^2 = 858.49w
60hz 22.5^2 = 506.25w

Now we go to the final aspect of tuning: measuring response using acoustical sweeps.


Forgot:
I have the Front channels on Highpass filter from the HU at 250hz
Rear channels Highpass from the HU at 120hz, Lowpass from the amp at ~300hz
Sub channel Lowpass from the HU at 100hz, Subsonic from the amp at ~15hz

 

Initial tuning

The way an Acoustical Sweep works is by sending a 20hz-20,000hz sine sweep through the speakers and then it is measured by a calibrated microphone to produce this:

I did this on my phone using the Dayton iMM-6 calibrated microphone and the Room Acoustics Meter app (Android) and I also used the AudioTool app ( Android) for live RTA info to aid in the equalizing process between RAM sweeps.
Microphone and home-made stand:

RTA screenshot

The goal in all this is to use time alignment to balance the signal coming from all the speakers to hit the listening point (driver's seat) at the same time and thus provide as "perfect" a listening experience as possible

I'm not going to bore ya'll with the details, but as of 12Feb2023 this is where my system is at:
(Ignore the pink lines, the Red and Blue are the important ones. They are the main Left and Right signal readings)

You can see that there is a separation between 100hz and 600hz which tells me that i need to go back in and play with the rear speakers' alignment settings

This is pretty much where I'm at right now. I've been busy with my home audio projects and customer projects so I haven't gone in and done a recent sweep. I also have recently installed REW (Room EQ Wizard) on my laptop, so we'll be having fun with that too.

 

System demo video and old school excursion show

 

Running ideas through my head about completely re-doing my amp setup...
This time I'm planning to use some of the "collector" gear I have in the closet.
3x Soundstream D100ii
1x Soundstream 1000SX

This build will actually involve
1) Basically building the Steeda rear seat delete cover out of wood
2) Running all the speaker wires that are currently laid in the car to a terminal strip (left bottom of drawings)
3) Running all RCA's that are currently laid in the car to an equivalent "terminal strip"
4) Installing busbars/distribution blocks for the power/ground wires

This way I can swap out/move around the amp layout and I'm no restricted by the lengths of wires currently installed. All I have to do is run appropriate lengths from the terminal strips to the amp positions

Without a DSP

With a DSP