Budget Build in My 4Runner

[Smitty]

I'm doing a budget build in my 4Runner. I am only concerned with sound quality and have a very limited budget for this project. It is also kind of a tinkering experiment. For any newbs reading this, you can achieve good sound quality on a budget. You just have to understand there are compromises. You also have to be willing to experiment and do more DIY fabrication. In my case, I'm using home audio drivers. Car audio drivers are generally designed with the environment in mind. The noise floor in a vehicle is much higher than the home listening environment. The acoustical properties of a car are also very detrimental to the audio system. Also moisture mitigation and mounting, etc... I'm going into this knowing I will not have the output levels that higher end car audio speakers have. I have no desire to compete, I just want my music to sound good. I can shoot for 90% of the sound quality but may only have half the output. In my case, that's fine since the OEM system has almost enough output, it just sucks doing it.

I tend to use things I have lying around and will also make many changes along the way so my initial speaker installations usually have temporary configurations until I decide exactly what I want. When it comes to aesthetics, I try to make things appear as stock as possible. As you'll see below, I care more about safe transfer of power than I do a flashy car audio fuse holder.

Disconnect the negative battery terminal before working on your system.

There is little to no room right next to the battery so I decided to make a mount using two factory threaded holes on the back side of the fender.




I dug through my miscellaneous screw bin and found some OEM bolts from another vehicle that fit the threaded holes. I also had a piece of plastic from another old project. After trimming to fit around a raised portion of the fender, it was perfect for this application.



For this build I used a Littlefuse mega fuse holder because I had one. They can also be found at some parts stores. https://www.amazon.com/FuseHolder

I don't use the pretty looking car audio fuse holders anymore. In my experience, the plastic becomes brittle over time and the covers of some are designed by kindergarten children. The covers either don't stay on or difficult to remove without breaking. I also don't like the set screw style connections under the hood. I'm sure there may be some nice expensive ones but I'm cheap. I've yet to have a problem with the two units I prefer.

This is another one I like. https://www.amazon.com/Blue-Sea-Systems-Safety-Block/
It is a marine grade unit and has a watertight compartment encasing the fuse. It also has a provision to carry a spare fuse.



I found some 1/4-20 Allen screws that fit the mounting tabs perfectly. I threaded the mounting plate for the screws. They do go through the plate far enough I may install some lock nuts on the bottom but so far they hold nicely.



For this install I used 4 gauge KnuKoncepts Kolossus Fleks Kable. I make my own connections using a hammer crimper in a vice. I keep an assortment of cable lug sizes around because I like them to fit around the screw as well as possible. I used two different sized lugs in this build so far. I tinned some copper battery cable ends before attaching them to the cable. I used heavy duty adhesive lined heat shrink at the ends of the cable. This was Tyco heat shrink you can get at Home Depot. Toyota uses flex loom and tends to wrap the entire length with electrical tape. I did the same. I usually make it match theirs but this time I was feeling bold so I used red.




The cable attached to the battery post perfectly and fit under the OEM post cover. You can see in these photos I routed the cable between the battery and power distribution module. Then it routes through the void in the fender. This is why I double wrap may cables. I make every attempt to ensure there are no sharp edges near the cable. Even so, make sure to inspect the outer shell for chaffing after a few miles and continue to inspect periodically after that. There is no protection between the battery and the fuse holder other than the steps you take to ensure a quality install.




The lugs in this fuse holder connect the cable directly to the fuse.



All Buttoned up.



Here you can see I also connected a small section of 4 gauge cable to the OEM ground on the fender. My system may only end up around 500 watts so I'm not really sure it will make a difference but its a good practice.

[reithi]

Looking good......can't wait for more.

[Smitty]

I installed some mid-range. In keeping with my super budget experiment, I chose the Dayton Audio RS75-4 3" Reference Full-Range Driver 4 Ohm. I got these for $22 each. They are small and fit easily in the OEM space in the dash. I was surprised at how well they sounded just hooking them up to the factory system. The majority of the motoring public would think they sound great and would stop there. Even though they are full-range, most of the members here would agree a true tweeter is in order. Crossing them over between 600 hz and 1 Khz increases the power handling considerably and makes this a decent mid-range in a 3 way setup. Without a high-pass, they will quickly distort at mid volume.

I took the factory plug off the OEM tweeter and modified it with leads to connect the new mid-range. I was not worried about reusing the factory speaker. These are cheap enough I can leave them in the truck if I sell it. I will eventually be running new speaker wires as this will be an active setup but these plugs can be thrown back in to return the OEM wiring if needed.



I made mounting plates out of 1/4" plastic which mount to the factory speaker bracket. I used a hole saw for the main hole, then a jig saw to cut the outer shape. I cut the hole first and so I could make sure to mount the plate to the bracket as close to the same position as the OEM speaker as possible.



I had to notch the inner hole for terminal clearance.




Using the OEM screws, I attached the mounting plate to the OEM bracket.



I then used some #4 x 5/8 screws to mount the speaker.



I placed a piece of CLD on the A/C duct at the bottom of each speaker compartment. I then made a ring with some open cell foam and placed it in each opening.



I attached a ring of closed cell foam to the ring on each of the factory grills.



I did not treat the space further or attempt to seal it with CLD as others may do because I may not keep these. I'm still experimenting but so far these have exceeded my expectations.
I chose these over other larger speakers for a few reasons.
You can put larger speakers in the opening but I have seen many installs which required bending the bracket and changing the position of the speaker. I wanted both of mine to have the same position and angle in relation to the windshield.
Others have had to grind away portions of the grill because the speaker position caused the surround to make contact with the grill. With these speakers and this method of mounting, I did not have this issue.
I may try the 4" version of this speaker later but I doubt it after hearing these. I'll know more when I get the rest in.

[Smitty]

Looking good......can't wait for more.

Thank you. It will be slow going but I'll get there eventually.

[TheTodd]

I’ve used those RS75s in multiple builds. I think they sound great, but you’re right, they definitely need a tweeter. They’re missing just enough “sparkle” that a tweeter is a must. I had them paired with the 7” woofers (RS180?) in a 90 Jetta coupe run off a Soundstream Ref 5ch. I loved the way that car sounded

[JCsAudio]

Looking good!

[Smitty]

I got some more time to work on the install. It's been very slow but I'm getting to really hear the difference. I installed some very old amplifiers under the front seats. An Eclipse 3640 and a 3520. They still work great. I chose the Dayton DSP-408 for this build. Its affordable and does everything I want for now. This is my first DSP and WOW! I wish I had invested in time alignment before now.

I tapped into the factory output with solder and heat shrink, then wrapped everything back up and even tried to match the factory blue tape. The taped flex loom is my wire.


I installed the DSP in the glove compartment which gives easy access to the USB port.



There is some hiss in the Dayton DSP-408. At full volume (+6db), it was readily apparent. At the 0db setting I could still hear it with the vehicle idling and the AC on. The DSP seems to mute the output when a zero bit track is playing which made troubleshooting difficult. I used a low output track on an IASCA CD that says "Warning, reduce volume." Its intentionally recorded very low which conveniently allows the noise floor to be observed better. Turing the unit's main volume down I could no longer hear the hiss with my ear near the speaker and intentionally trying to hear it. My amplifiers are very clean which allowed turning up the gain to compensate for the lower DSP output.

[Smitty]

The 8 inch Dayton RS225-4 woofers fit the doors easier than I thought they would. I did the initial fit and made the adapters out of exterior plywood. I will be going back into these doors for sound deadening and hope to have some permanent mounting rings made by then. My aim is to have some 3D printed with my mock up as a base template. I did MDF rings in a door once and it was bad so I don't expect these to last.

I ordered some speaker plug adapters for the spacers that will be made but used a quick budget trick with the OEM speakers for the temporary fit. In all honesty, these work just as well when done correctly.

I clipped the leads from the factory plug.



Then removed the connector.



I then put the plug in the factory wire and meter the connector back to the amp. I mark the plug for reference and solder new wires to the tabs.



I just soldered some 16 awg wire to the plugs and applied heat shrink. For a really sharp looking adapter, look at this build. Thank you Chithead!

I drilled a couple of holes and fed the new plug into the adapter ring. Sorry, I was all out of drywall screws but found the exterior grade pan head SPAX screws to fit perfect.



I ground down the ridge on the back of the OEM speaker grill for clearance Clarence.



I installed some CCF around the speaker and buttoned it up.





I was very surprised they fit so easily. They actually sound FAR better than I expected. I honestly didn't expect the sound to be as good as it is. I've never had a mid bass speaker larger than a 6.5". I currently only have these and the RS75 in the dash. These have solid output to about 30 Hz at moderate volume. I almost don't need a subwoofer.....almost. I still plan a sub but need to get the tweeters in. I'm currently making pods for the sail panels on the doors and I need to get the Resonix project done in my Camry. This means the sub will have to wait.

[JCsAudio]

What are you planning to use for a subwoofer? Go for a round port design using a 10” subwoofer and 3” Parts Express Precision flared Port. With that alignment you’ll get decent output and very low distortion so long as you use a decent driver. The Alpine SWS is actually a good low distortion design. I may be able to put together a design for you if you’re interested once I get my computer back from repair.

[Smitty]

I'm still in the planning stage on the sub but I'm looking to fiberglass the rear corner pocket. I'll most likely go with a Dayton HO 12 if I can get the air space. Frequency response, sound quality, and budget are the highest priorities. Output just has to be moderate. I know its sacrilegious on here but a single 10 will have enough spl for me.