I just got done installing a set of Skar NPX8-4 8" woofers in the doors. I used the adaptors designed by
@RWAudio printed using the STLs that he so generously provided on his site plugged here:
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The adaptors are great, RWAudio even included a PDF with tips on how to print them. I followed the suggestions but printed at Super Draft settings. Nevermind the zits on the inside of my print, I think my filament isn't properly dry. With this detail setting it took a little over 12 hours each on my Ender 3. The only bummer with this setting is that because the speaker mounting surface is at a slant compared to the bottom, you end up with a pronounces stairstep between the layers. You could adjust the quality for the upper layers, but I just filed them down and used some speaker mount foam, no problem. Don't skip on the inner and outer brim because with something this big you don't want the temperature differences to warp the print away from the bed. This model has reinforced channels for 4 screws and even clips into the door just like the stock woofer does. I was able to screw the speakers down very tight without the holes stripping. The Skars had 8 screw holes, and this is designed for the Focals with only 4, so I did drill and use 4 additional holes. This helped to pull the speaker and mount together quite a bit better because of the speaker foam I used. I imagine any standard 8" speaker would fit these mounts. Thank you
@RWAudio!
I took some measurements with just the mount installed to get an idea of what depth speaker could be used. These adaptors were designed for the Focal ISU 200, which has a mounting depth of 2.5" The mounting depth between the surface of the adaptor and the window hardware in the center is 3", but because the mount is thinner at the bottom to maintain the stock mount angle the clearance is reduced to as little as 2.5" at about 3" outside of center. You could easily use a speaker with a larger magnet with a 2.5" or less mounting depth. With a smaller neodymium magnet you could likely push it closer to 3" deep. The Skar has a 2.4" mounting depth.
Do yourself a favor and install plenty of sound deadener. Don't skimp, cover every inch of every bit of the outside door skin you can reach through the speaker hole. Cover every inch of every flat surface of the plastic door panel. Do what you can with the inside door metal depending on what you want to dismantle. I cut small pieces and stuck them all over the underside of the speaker mounting surface.
I did a side by side comparison with one speaker installed. The biggest difference was the bass, with the stock speaker having a much better frequency response under about 100Hz. All other differences just needed an EQ adjustment. The Skar drops off noticeably under 80Hz, while the stock speaker was easily producing 60Hz tones. I adjusted the equalizer and was able to get the Skars bumping pretty good down to 80Hz, but they still aren't going to be impressive below that without additional amplification. Because I am going to add a subwoofer, and generally cutoff at 80Hz anyway, I am more interested in the 80Hz+ punch from the doors. If you are not going to install a sub, just pony up for the Focals which have a better frequency response below 80Hz. The Focals claim a frequency response as low as 40Hz, but you'll need to put some extra watts behind them to get that low.
With both left and right speakers installed I spent some time with the equalizer. Remember, when adjusting equalizers adjust DOWN, not up. I dropped the middle band to the bottom, curved the highs up so the highest band is at zero, and put the bass a bit above zero. I am VERY happy with this change, even though I still feel I've lost some low end. If I hadn't listened side by side I wouldn't have noticed the lower frequency difference, the Skars have a very acceptable bass response. I think this is an improvement, and am confident that once I get my DSP installed I'll be able to tune everything to my liking and add a bit of power for some more punch.
I had already changed out the left and right dash speakers with Infinity coaxials, and I've had the fader set almost all the way to the front. I don't know what it was, but when I would fade in the rear door speakers it seemed to mess up the imaging. It didn't take much for me to be very aware of the sound coming from the rear. After changing the front door speakers I found that fading to the middle actually ADDS something now without ruining the staging. My theory is that before changing the front door speakers there were certain frequencies underrepresented between the Infinitys and stock front woofers. Fading in the rear door speakers brought some of these frequencies back in, but because they were located in the rear if threw off the staging. Now when I fade in the rears the sound is supported rather than added. It produces a fuller sound in the midrange without making you aware of the location of the rears. I settled on a fade of just barely forward of middle, and balanced slightly to the passenger side.
I'm not done yet, still need to add a DSP, sub, and add in the tweeter and A-pillar speakers. From what I've learned so far, here is my advice:
- Don't put coaxials in the dash. Tweeters in the dash bounce off of the glass and disperse the sound. High frequencies are more directional, put them in the mirror locations where they belong for proper imaging.
- Don't skimp on the sound deadener. It is not cheap, but as much as you may read that you only need 25% or 50% coverage, I don't think that is true. Cover as much as you can, do it right the first time. I can tell the difference, especially on the plastic door panels where I covered more of the left side than the right. I'm going to pull the driver side apart again to take some more vibration out of the panels by my leg. I also did the trunk and subtrunk in preparation for a sub, and after doing 50% coverage I had to go back and add more.
- As long as you choose a shallow depth speaker for the front doors, no deeper than 2.75" or so, you aren't limited to a neodymium magnet. If you keep the depth under 2.5" you can go nuts with the magnet width.
- Read everything
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