This update is a little disjointed and all over the place, it was a weird week.
I finally got all of the power steering soft lines in, have I mentioned I hate waiting on parts?
I thought I had taken a pic of the state of the engine/steering rack/general area before I started cleaning but I did not. It was horrid, the black mess was 1/8-1/4" or more in places. The top of the rack where the lines connect was covered all the way over the top of the nuts that hold the lines in place. It took a few days of soaking, scrubbing and poking it with a stick to get it clean enough to work on.
This isn't really clean, but it was good enough to work on. It had been leaking a very long time.
There were no obvious signs of where it was leaking but the return and feed hoses were rock hard and a little chewed up at the connection points. The pump and brackets cleaned up nicely, this was the only number I found on the pump, I have no idea if it is a replacement or not, I did not take the time to run the number and see.
Project Subwoofer, Part two.
I did finish constructing the sub box, It took a lot of fiddling to get the port length and box volume close enough to make it play like i wanted. The port ended up being 1.5" tall, 6" wide and almost 26" in length which should be tuned at about 28hz, I measured the center of the port to get that length. Total box volume, taking into account the volume of the port, which you typically do when the port is internal to the box, not sure how an external port factors in, I decided to include it which gave me approx. 1.1 cu ft of volume. It does play cleanly and low so I am happy with it. I do have a little buzz at 70hz so I need to figure where that is and correct it.
The folded port...
All buttoned up and ready to play...
How much space did all of this cost me? Not very much, the baffle took up 1.5x11.25x32" which is barely noticeable. There is still enough room for an overnight bag or two.
I am going to revisit the amp rack at some point, probably when I replace the amp as the new amps are significantly smaller in total footprint than the old RF beast. The original Bose speaker cover is being used to cover the port. Now I need to build a cover for the sub, I have a few ideas I am kicking around.
I do realize the passenger cubby isn't stiff enough to prevent any resonating/flexing so I will need to address that. As I stated earlier adding to the interior of the box will only make the volume less and I cannot make the volume less and hit my tuning design. That leaves adding mass and strength to the exterior of the box as much as I can. I am a bit of a hoarder, if something is useable I tend to save it, especially if it something not easily replaced. I have some compressed fiberglass plates that appear to be a perfect fit for the need. I cannot tell if these are SMC or a G10 variety, but they are incredibly stiff.
They are 1/8" thick, 2" wide and 11.5" long. I wanted to see just how stiff so I bent one of them. The deflection with 10lbs of lead dive weights was 1/8" over about 10" of span, it laughed off the first 5lb's. That's pretty strong!
My plan is to strip and sand the underside of the passenger cubby and epoxy a few of these to it. The size works out almost perfectly and should greatly increase the rigidity of the cubby. I will undercoat it when finished to make it blend in. That will happen later because listening to the sub it actually sounds good as is. I just know I can tighten up the bass more with a stiffer box.
I did a lot of tuning of the bass, bought a little O-scope to set the gains. The little FNIRSI DS-O152 mini oscilloscope was impressive and can do a lot more than I would ever need. I first determined the max volume of the headunit before clipping was present, next the gain of the EQ and finally set the gain for all 5 channels of amplification with the bridged sub gain set at 40hz to 120hz and the left/right, front/back speaker gains at 500hz, 1khz, 3.5khz and 8khz. It was pretty easy with downloaded test tones. I spent most of the frequency tuning with the sub to get it to blend in nicely with the fronts. I will need to spend some time tuning the front speakers as they are a little bright on "S's" but overall the sound is fantastic. The sub plays 25hz at about -6db down, 35 hz at about -3db and 40hz flat, you can feel the 25hz with the volume up but it is still 40hz dominant as expected.
I made a little 2 minute video of it playing a bass heavy song. If you know the Boz Skaggs album Dig they you know it is one of the lowest bass recordings out there for mainstream music. It is a spectacular album as well. I used my Blue Yeti first to record the sound and cellphone for video then mixed them together. I was unhappy with the Blue Yeti and it's bass response, which I suspected I would be, it is a great all around mic but better for spoken voice than low bass recording. I hesitantly pulled out my Marantz MPM-100U because it a little on the fragile side but it recorded the sound perfectly. I did no post sound enhancement so the volume is a little low and the S's a little bright, which I will try and tune out with the EQ. Enjoy this little snippet, best listened to on real headphones, home theater or lastly a good set of ear buds but don't expect to get the low bass with ear buds. It obviously will not sound this clean while driving but it will give an indication of how the system sounds.
