Acura CD Changer Pinout
If you use an aftermarket (Alpine) CD changer instead of the Acura branded version you MUST use an adapter cable or the sound will be out of phase because Acura switches pins 2 and 4 compared to the standard Alpine pinout.
This is for informational purposes only -- and I do not guarantee it is correct! I do not recommend you make your own adapter cable. They are available for $30 at any car audio store which sells Alpine equipment. That is a small price to pay to skip the risk of frying your stereo system or worse. For more information see the Accessories / Sound System section.
The following image represents the ALPINE pins overlaid on the Acura connector. For proper operation, pin numbers 2 and 4 must be reversed. These are the SIGNAL GROUND and RIGHT SIGNAL wires.
Plugging the changer in directly might not damage the shuttle, however the quality of the sound will be out of phase. Basically your left speaker will use the (+) --> L+ and (-) --> R+ terminals while your right speaker uses (+) --> Ground and (-) --> R+. Not exactly the ideal situation.
CD Changer Installation / Mounting
There are two DIN cables pre-wired into the trunk on model years where the built-in phone was available as an option. The blue one is for the CD changer, the other one is for the phone.
[KJ] The CD cable enters at the left of the trunk, but the factory unit installs at the extreme right of the trunk. They use an extension cable across the front (car's front) of the trunk. This keeps the left of the trunk free in case you need to put a flat rear tire in there.
[SJB] I finished up my CD changer installation (Apline CHM-S601) today. As anyone who has tried it knows, mounting the changer to the Acura mounting kit is a real pain in the ass (isn't the mounting kit supposed to make it easier? ;-)
Some have had to drill holes, fabricate new mounting brackets, etc. Through determination and dumb luck I figured out a way to attach the changer to the mounting bracket without any drilling, fabrication, or extra parts. If you try to attach the Alpine brackets to the changer like they suggest, you'll notice that you can't even fit the whole thing within the Acura mounting bracket. However, if you turn one of the Alpine L-brackets around and attach it backwards on the changer so that the top part of the bracket hangs over the changer (instead of away from the changer) you will now notice that the whole thing fits within the mounting bracket, and two of the holes will match up, one on either side of the changer. You can use the short, thick bolts (6 x 12 mm) from the Acura mounting kit to fasten the Alpine bracket to the mounting kit bracket (if you use the longer bolts from the Alpine kit, they hit the trunk wall when the changer is in the upright position).
A single bolt on each side doesn't make an ideal connection, but each one is attaching a flat and wide area of the bracket to another, so you can tighten them up as much as you want without hurting anything. It all seems pretty sturdy. The stresses on the changer itself are supported by four screws on the Alpine L-brackets. If you're really concerned about stability you could easily drill another hole on each side - there's plenty of metal left on the brackets for more holes.
Note, all of this probably applies only to the Alpine S601 and the Acura mounting kit. If you're using the S600, S604, or whatever, you're on your own. If you are using the S601, this whole email will make much more sense when you actually get to the point where you want to attach the changer to the mounting kit.
[MN] I installed my CD changer last Friday. It was a bit more difficult than I thought it would be. And this is coming from someone who has *major* experience designing and installing mega-car audio! So, I thought I'd walk through my installation and highlight some of the "not-so-obvious" things I encountered during the installation ( for anyone who cared. ) :-)
Taking the carpet out: First, I figured out ( but almost not ) that you don't have to take the rubber trunk gasket *entirely* out - just the part that is holding the carpet in. The directions don't clearly specify this. Second, the little clips that hold the carpet in: I couldn't figure out how to get them out at first. Seems that you have to hold the outer ring part with your finger or something, then unscrew the center part with a #3 phillips. And if you screw and screw and screw, and that center piece *doesn't* start rising, then you've got to apply pressure underneath it with some other little tool to help it up. ( boy, I just re-read that last sentence, and I'm sure I'm gonna hear about it !)
Anyways, on with the install. The end pieces ( carpet ) are easy to take out. Snaking the big DIN cable was easy, but I wouldn't tape up the ends just yet like the directions say to do. Because when it's all said and done, you'll have extra cable left over, which you'll want to tuck back into the back, and I feel that this is harder to do all taped up. By the way, I got that long cable in the kit with the CD bracket from Hoehn - don't know where to get another one. :-(
The bracket stuff is a bitch ! ( pardon my french ). First, the directions weren't perfectly clear enough about having to cut those two little gray cable holders that are snapped into the top bracket mounting holes. I had to convince myself multiple times that I was doing the right thing by cutting an actual piece of my car. You need to cut these right where they meet the cable ( in other words, leave some of it in the cable, where it's taped in ). Then, somehow ( this was difficult ), cut the rest out of the hole.
Once you do this, you can ( attempt to ) mount the two inner brackets to the inside wall brackets. The holes did not line up too well. I had to forcefully "bend" ( not permanently ) the brackets to get them to line up, then start the bolts before letting off the pressure. At least I didn't have to re-drill or elongate the holes. Don't worry, I had to do *plenty* of that later...
Ok. Once the brackets were installed and the cable was tied up into the tops of the three hole'd brackets ( instructions are OK ), then you can put the carpet back, I recall. By the way, the instructions tell you when to re-install the two side carpet pieces, but give you NO CLUE as to when to re- install the main piece! No biggee, I put it in then, no problem.
OH ! You have to cut holes in the passenger side piece - no biggee.
Assembling the actual CD changer bracket is easy, mounting it was difficult, getting the aftermarket changer to mount to the bracket was horrible. The angles on the big brackets don't seem right, but it *does* fit ( bolt onto the car ) - it's not easy, so don't think you did something wrong
The changer I bought was an Alpine CHM-S601 or something like that - the other model, well, actually, I was told that the other model ( the one that supports "data" ) would NOT work. However, I read of an NSX guy on this list who has one, so maybe the salesman was giving me a line...
IMPORTANT: The following are my thoughts on installing an AFTERMARKET CD CHANGER, NOT
THE STOCK ONE !! I don't want
The directions for mounting the little mounting brackets that come with the CD changer are misleading. The brackets must be mounted for what the directions say is a horizontal installation, even though it is mounted vertically. Also, *I* would secure these brackets with 4 screws each, not 2 like the directions say. Doing so requires you to elongate or re-drill the other two holes. I still thought it was worth it. Very solid now. I had to actually mount one of the brackets facing *out*, and the other one facing *in* to get mine to mount up right. Oh, and remember to move the springs on each side of the changer to the "Vertical" position. *Now* the directions help.
I had to re-drill holes in both brackets on the CD changer bracket, AND holes in the small backets that *came* with the CD changer ( the ones facing in and out ) to get it all to line up. With no machine shop, no vise, etc., this was a bummer, but not too bad. Once the CD changer is bolted into the bracket and fits alright, now you can take it out and mount the CD changer bracket again inside the trunk. With the bracket mounted, re-bolt in the changer, plug in the adapter, and you're ready to go ! I kinda pulled up the bottom of the side carpet piece and tucked ( carefully ) the remainder of the cable behind it so that practically none of it showed.
Another thing: the "nuts" that come with the CD bracket kit - JUNK ! Toss them big time and get some of those nuts with the nylon thingy ( aircraft type ) that kinda self lock. MUCH cleaner. They're OK for the brackets that are covered up behind the carpet, but NOT ( in my opinion ) for mating the changer with the bracket.
When I turned it on, I couldn't believe the sound ! :-) I was looking into replacing the mids and tweeters with some Boston Acoustics Pro Series before, but with the vast improvement in sound quality over the tape player ( should have known... ), I'm not touching it !!
So, I hope sharing my lengthy experience helps someone someday.
[RAH] I installed the Alpine S601 CD changer in my car this past Wednesday, and I can report that all went very well. I decided NOT to buy the Acura $90 CD installation kit, and instead used the mounting plates which came with the Alpine unit. I plugged the CD extension cable into the NSX's DIN plug in the left front of the trunk, and ran the cable underneath the floor insulation to the center section where the jack and tools are. I then drilled four holes in the bottom of the aluminum trunk floor (ouch!!) which actually wasn't too bad. I mounted the CD changer at the LEFT rear corner of the trunk, which I think makes more sense than running all that cable around the perimeter. There is about a 2-3 inch section of cable that shows, and this goes right into the center section to the jack tools. The excess cable is easily wound up and placed in that area. This was a vertical install, BTW.
This whole installation took me about an hour and a half, and I figured I saved $600 over the Acura-installed version.
CD Changer In Glove Compartment
[CWI - 99/5/12] This mod is only available to NSX years 1991 - 1992 as a passenger side airbag reduces the glove-box size in 1993+ cars.
I'm lazy. It's one of my faults. However, in addition to being lazy, I am creative… Here are instructions to mount a CD-changer in your glovebox eliminating the need to stop your car and walk to the rear, pop the trunk, and change magazines when you want to hear some new tunes.
I know of two alpine units that due to their size and hardware will work with the NSX head unit. They are the Alpine 620 and Alpine 611. The 611 is last years model and has been discontinued. If you find one, buy it and save about 50 bucks. This years model looks a little better and has a faster disk transfer speed. All Alpine units that are M-bus compatible will work with the NSX. Only these two (I think) due to their size will fit in the glove box.
Here are the directions:
1. The cable used by the stock changer (all NSX are prewired and have this cable attached to the head unit) has a pin-swap which render's aftermarket Alpine players sounding poor. Remove the passenger side well panels to the right of the dash. You will need access to the rear of the head unit. Remove the changer's DIN cable. If you have big hands, you will also need to remove the driver's side panels. This will allow you to have two hands to free the cable. The cable plugs into the head unit in the rear left. It is pretty easy to remove. Plug in the new unit's included cable.
2. Remove the glovebox. The glovebox is held in place by three screws on the top, and three on the bottom. Look and you will see them. All phillips screws.
3. Mount the CD-player's side brackets to the first angled position. Make sure to set the spring to this angle. Place the CD-player in the glovebox. Mark where you will need to drill into the glovebox for the brackets. Also, mark the rear of the unit where you will need to cut a hole for the DIN cable to pass through the rear.
4. Test your location (which should be in the middle of the glovebox pushed to the rear) with the glovebox door to make sure it all fits.
5. Drill the holes and cut the rear hole.
6. Bolt in the changer and attach the DIN cable. Put the glovebox back in. You are now good to go. Put in your favorite CD and listen to your sweet success.
The whole project took me about 4 hours. I bought the 620 unit because the previous one was not in stock. It cost me 299 bucks. Much better than the stock unit's 900 dollar price tag, plus I can change magazines in the car! In addition, the disk change speed of the unit seems like it is twice as fast. Sweeet!
[GS] 1. Alpine, 6 disk, CD-changer (Model 5601) was mounted horizontally under the right rear trunk lip. The unit is small enough that only a corner shows when looking down into the trunk. Trunk space preservation was the goal and was successfully achieved. A commercially available adapter was used to unscramble the prewired Acura CD cable into Alpine standard configuration. The Alpine factory cable was used to extend the Acura prewiring from the left trunk wall where it was tucked behind the carpeting over to the right hand mounted Alpine CD. Note: The CD could not be mounted horizontally on the left because of space consumed by the antenna motor. Acura has a fancy swing-out vertical mount for the right side but then again, Acura wants $1200 for a $370 Alpine which has scrambled wires. Someone else published an installed price of $350 for the Alpine from Good Guys. Swing out mounts are available from third parties if you insist.
2. A Macintosh model #427 power amp. Power output is 100W X2 @ 4 ohms with bridging capability for driving a sub. If wired in a three channel configuration, power approaches 400W total. I had wire for the sub woofer installed but not connected. Rudimentary electronic crossovers and equalizers are built into the amp. The crossover was not used but the equalizer was perfect for countering the bass boost loudness compensation circuit in the factory Bose radio. More on that subject later. The amp was mounted on the left side of the trunk firewall in the indentation. A wood base was mounted to the firewall behind the carpet with silicone adhesive. The amp is screwed down through the carpet to the wood base, a very neat installation. All wires exit the left side of the amp and go immediately through the carpet into the wiring duct.
3. A pair of Dynaudio speakers with passive crossovers (model # 240), are mounted behind the factory grill. These are new speakers built specifically for mobile audio use. Dynaudio drivers for home stereo have been used successfully for some years now in high end car installations. The model 240 set is a ruggedized, all weather version of the 7" home mid-bass and 1.1" tweeter. A matching, adjustable passive crossover is part of the set. Both the 7" and 1" speakers can be adjusted independently through taps on the x-over. Speakers and x-over were mounted to flake board panels and the paneling to the door using silicone adhesive. Sections of Dynomat sound deadening material were glued to all interior surfaces of the door, a must for quality sound according to everyone I talked to.
4. The Acura factory Bose radio was kept in order to preserve the factory look and because of its tight integration with everything else (phone muting circuit, CD pre-wiring, center channel and sub driver channels). The truth is I'm chicken when it comes to sawing on the interior trim. The other reasons just make me feel better about the choice I made. Anyway, the Bose radio has pre-amp output levels which are perfect for wiring directly into the Macintosh amp. In a previous posting I said I would have the radio tapped between the power amp and the pre-amp in order to bring out proper drive levels for the subsequent amplifier. Many thanks to Alan Watkins for saving me the expense of finding this out the hard way. Apparently some Bose car configurations are high level, direct speaker drive setups and others have line level outputs driving self-amplified separate speakers. Fortunately, the NSX falls into the latter category. Al T. also unearthed the fact that there was about 3 to 6db of boost in the bass band. As luck would have it, the Mac amp has a 3 and 6db cut circuit covering the bass band (below 150Hz)...perfect! Both the Bose radio outputs and the Mac inputs are floating, no chassis ground and that is the way they should be wired.
Underlying noise with no program playing, volume control all the way up, is very low. No discernible hum or engine spark noise and only a very small amount of hiss. Again, good job Alan! The factory center channel and passenger kick pad mounted sub woofer remain connected, driven by the Bose radio. However, the sub adds very little to the low frequency end compared to the Dynaudio 7"ers. The purist could disconnect it without loss of significant sound power in the bass band. The center channel (at drivers right elbow) fills in the middle as Dr. Bose intended and who am I to argue. It's still there and playing for now.
As expected, there is an awesome improvement in sound quality and power. Sound imaging is amazing! I have some synthesized music for critical listening which puts the system to the test. One passage orbits the sound image point around the cabin. These things are always a bit subjective but it impressed me... And I suppose that's all that really matters. Anyone out there who needs more info can send E-mail or reach me at (619) 551-1000 X178 during the day. Hope this helps someone else in NSX land suffering from lack-o-sound disease.
[JW] The stock (4"!) Bose sub was replaced by the 10" JL Audio. The install can be complicated and I would not do it unless you have complete confidence in your installer. In mine, the box was custom fit to the contours of the foot well by making it fiberglass. They built and tried two wood boxes but gave up on that idea because of the many angles and odd shape of the foot well. The box had to be too big to get the required air volume.
Overall, I lost a few inches of leg room to the box because it is a 10". But hey, I don't have to sit there <g>. It really isn't bad, in fact the angle of the box makes a good foot rest for the passenger as they get a great foot massage (depending on the volume). One amp is running the whole system. It is a top of the line pioneer 4 channel. Two channels are going to the sub. Two are going to the MB Quart separates.
There are only 5 speakers in the whole system and it sounds 10 times better than the stock unit. Putting in a center channel would have unnecessarily complicated things and added alot of money. It would have required a second amp, and would have to be set up to a different volume so as not to overpower the other speakers.
I chose separates for even better sound quality. The 6 1/2" speakers fill the door, have there own enclosure, and are behind the stock grill. My installer found the best place for the tweeters was mounted in the dash. The dash has a natural angle towards the driver and passenger. Since holes have to be cut I would take it to a GOOD installer.
Finally, the head unit is very nicely installed. I would be careful here. You have to do some cutting and if it is done wrong it won't look good. Mine utilizes the very bottom of the stock radio opening which takes up a large amount of space. The remaining openings that used to be the tape player etc. was covered from behind with shinny black acrylic. VERY NICE.
[SSZ] I replaced my broken OEM unit with an aftermarket one, which required cutting the dash, because the dash has holes custom placed for the buttons of the OEM system. As a result, you need an experienced person cut the dash and mount the new system. This involves some labor cost, but if the technician is good, the new dash/stereo does not look bad aesthetically. One tip though, don't use a system that has many buttons protruding outwards like the OEM's; since the face of the new system has to be pushed forward, a flatter face will look better.