Nice stereo install -- my recommendations.

[FastWoman]

Hi all,

When something works out well for me, I like to share it with y'all. My stereo system recently went (somewhat) south. It wasn't a very good system, and it turns out the PO had miswired it, with the two-channel power amp driving two full-range speakers PLUS one subwoofer that was wired across the two. Strange. Anyway, that killed the little amp.

My goal in re-doing the system was to achieve clean sound with respectable power, but not to create a system that would shatter windows in the neighborhood. My listening tastes are very eclectic -- classical, jazz, rock, more jazz, folk, even more jazz, and lastly... jazz.

What I was retiring:

-- The power amp (crippled)

-- The huge subwoofer box in the back (a loose cannon and a space hog)

-- The OEM 8-watt B-pillar speakers (1978 Z configuration)

What I had to work with that was still good:

-- a Sony casette head unit, still just fine

-- a Sony CD player, still fine

-- a pair of "OK" Pioneer 6" full-range speakers in the doors -- not coaxial, no whizzer cone, just plain full range speakers

What I decided to add:

-- a pair of Boston Mobile Audio (Boston Acoustic) SE45 4" coaxial speakers in the B-pillar cutouts (35WRMS/80 peak, 90-20k +/- 3dB, 92dB SPL 1W/1M)

-- An Alpine MRP-F300 power amp (50WRMS x 4 channels when driving 4 ohm loads and 75WRMS x 4 when driving 2 ohm loads. I'm driving 4 ohms, but appreciate the stoutness of a 2 ohm amp.)

-- An Infinity BassLink 10" subwoofer (Harman Kardon)

The head unit has only two high-Z outputs (L and R). They feed both the L and R, front and back inputs to the power amp in parallel. I simply wired two RCA-type connectors at the ends of the L and R cables. The amp drives all four speakers in high-pass mode, with a 100 Hz rolloff. The amp then provides a pair of high-Z outputs for the subwoofer input, representing summated front and rear L and R channels. I of course use the same 100 Hz rolloff for the subwoofer.

The subwoofer is mounted between the driver-side shock tower and the driver seat. It's a tiny bit space-hoggish, but not nearly as much as the prior subwoofer box. It's also much lighter. The feet of the subwoofer are bolted with big fender washers to the false hatch floor of the '78, but it could also be bolted to the deck above the driver-side tool box.

I did my research on this subwoofer, and reviews are all good. I also looked into more compact subwoofers, which I considered putting under one (or both?) seats and/or in the floor area behind the seats. However, from what I've read, those have problems with inadequate power and/or early failure. The Infinity units, in contrast, seem to keep thumping away. A big selling point for me was the prominent heat sink fins. Heat is the enemy, after all.

The result? This has got to be the best sounding car stereo I've ever had, without so much as the assistance of a graphic equalizer, and I remember two of my prior Z installations sounding rather mediocre. It's cleaner and fuller than the 7-speaker Harman Kardon premium factory system I had in my BMW Z3, which I thought was pretty good (albeit lacking a bit in the deepest bass). The best aspect of this system is that the sound is so well balanced, with great clarity. Despite the full-range Pioneers (the weakest part of the system), the frequency response seems to be rather flat from bottom to top (SPL meter measurements not yet done). I don't hear any dead spots or strange resonances.

Kudos to the amp. I've always been a fan of Alpine amps. They're a bit hissy sometimes, and they don't boast the greatest THD specs, but I find their specs honest and their sound subjectively cleaner than so many of their competitors'. The fact that these amps can drive 2 ohm speakers says a lot. If I had time to doodle with this system, I'd be really curious to see how much harmonic distortion they really produce, as I now have an O-scope that will do the analysis. However, I fully realize the greatest source of harmonic distortion is wimpy speakers, and the second greatest source is anemic power. No worries on the power end.

Kudos also to the new 4" Boston Acoustic speakers! They really seem to pull the high frequency load all by themselves. Perhaps there is a bit of high frequency rolloff due to the Pioneers, but this rolloff is quite gentle and easy to equalize out. And BTW, yes, the high frequency response seems to get through the factory configured interior paneling holes just fine, somewhat to my surprise. I'll only add a note that the speakers aren't a perfect match for the factory cutout. Although they mount up flawlessly with the factory captured nuts, They leave a gap of maybe 1/8" to 3/16" all the way around. I filled that gap with a bead of black 5200 polyurethane caulk.

The only weakness of this system would be that the 20 Hz low end specification of the subwoofer would be rather "optimistic." But what do you expect out of a 10" subwoofer in a small box, anyway? In all fairness, the unit does as good a job as the subwoofer I have on my home theater system, which has about 3x the cavity size. I have to say I'm impressed with this little box!

Anyway, there you have it. It's a moderately priced system, but a very nice performer. I highly recommend any of the components I installed either individually or in combination. I make this recommendation as a lifelong electronics and audio geek, audiophile, and former acoustic researcher.

Could the system be better? Well, yes, of course. You could go crazy with your wallet and install something nicer that would gobble up all sorts of space. You could also design a much more highly powered system that could pound pedestrians in the chest as you drive by (if that's what you're into). However, considering its compactness and affordability, I think it offers a lot of bang for the buck. There's plenty of clean power for those who don't want power just for the sake of power. (And 400W total power is plenty, anyway!)

Edited March 20, 2012 by FastWoman

[siteunseen]

How cool is that! I'd go crazy pulling up next to an old Z that had some some smooth jazz bumping at a red light. You ever listen to Morphine? Such a good band but like alot of jazz guys the heroin took them down.

Edited March 21, 2012 by siteunseen

[Mike]

Sounds awesome! I always struggled with putting stereos in my 71 because it has such limited room. I remember driving I around as a kid with home speakers in the back cargo area. but after my restoration I installed a much simpler system.

Do you have any photos?

[FastWoman]

Siteunseen, I've never heard Morphine. I'll check them out. I'm a big Chick Corea junkie and have the Mad Hatter album loaded up, along with Jean Luc Ponti's Imaginary Voyage and Bela Fleck's UFO Tofu. Of course I also had to load up some Miles Davis (Kind Of Blue) for the inaugural drive.

Mike, no pics yet, but I'll take some. When I was a college kid, I remember packing a 12" 8 ohm subwoofer into the driver-side rear quarter panel recess of my old '75 Z. It was mounted into a 3/4" plywood enclosure that was flush with the hatch opening. Beside it was a power amp with graphic equalizer. Then I had miniature 8 ohm box speakers hanging behind the seats at head level. Nobody was doing stereo systems like this in the early 80's. It sounded pretty good, but the components didn't hold up too well in the Texas sun. Then the subwoofer sounded awful when its suspension rotted. It wasn't designed for car audio.

Edited March 21, 2012 by FastWoman