Hopefully someone will find this useful, I spent a couple hours putting it together after noticing all the threads with questions that could be easily covered in one big write up.
1991-1995 Acura Legend Stereo Information
What system do I have?
There are four different stereo systems that came in the different Legend trims.
1991-1993 Base ---- Honda
1991-1995 L ------- Standard Bose
1991-1992 LS ------ Bose
1993-1995 LS ------ Bose Premium
1994-1995 GS ------ Bose Premium
1995 SE ------------ Bose Premium
A standard AM/FM/Cassette deck that powers four standard 4 ohm speakers.
The Standard Bose system includes the 2200 model AM/FM/Cassette deck, which produces 80Wx4 (peak power) and powers a 4 ohm load on each channel.
The Bose system uses the 2100 model AM/FM/Cassette tuner and an 80Wx4 (peak power) amplifier mounted behind the rear seat. The Bose speakers in this system present a 2 ohm load per channel, which the OEM amplifier is equipped to handle.
The Bose Premium system includes a 2100 AM/FM/Cassette tuner with “Premium” printed on the cassette slot and a 200Wx4 (peak power) amplifier mounted behind the rear seat. The Bose speakers in this system present a 2 ohm load per channel, which the OEM amplifier is equipped to handle.
*Bose doesn't make their own Amp circuitry. Kicker made it for them from 87 - 92, then Boston Acoustics made the 93 up Amps.
How many speakers do I have? What size are they and where are they at?
In 1991-1992 models, there are four speakers, the locations of which are obvious. Two in the front doors, and two on the rear deck.
In 1993-1995, four tweeters were added. The front tweeters are mounted in front of the midrange speakers in each door, they are screwed onto the back of the speaker grills. The rear tweeters are located on the rear deck under their own grills.
The front speakers are 6.5S” or 6.75”.
The rear speakers are 6x9”.
The tweeters are a non-standard size and there are no known direct-fit replacements.
What if I want to replace my headunit or speakers?
The biggest difference in the OEM systems is between those that have the Standard Bose (2200) or Honda deck versus those with the 2100 Bose tuner and external 80 or 200 watt amplifier.
This is the rule of thumb....
If you have a Base or L trim
, you can change your headunit or speakers without any compatibility issues. For simplicity, I will refer to this as the "standard" system.
If you have a LS/GS/SE trim
, adding only a headunit or only replacing any number of speakers will present several issues which will be discussed. For simplicity, I will use the term “Premium” to describe both the Bose and Bose Premium systems. The two systems are quite similar, the only difference is the “Premium” logo on the deck and the output wattage of the external amplifier.
Replacing speakers in the Premium system
There are several brands which make 2 ohm speakers. The ones I know of are Soundstream and Image Dynamics. They can be difficult to find. The other option is to simply use regular 4 ohm speakers. The volume of the 4 ohm speakers will be half of what it should be due to the mismatched resistance. If you replace only the fronts, or only the rears, you can use the fader to compensate for the difference in volume between front and rear.
Replacing the headunit for a Premium System
If you want to replace the Bose tuner with an aftermarket headunit, you have several options.
1) You can bypass the Bose amplifier and remove it, allowing the new headunit to power the speakers. The headunit will likely be intended to power 4 ohm speakers, so if you have not replaced the Bose speakers, they will play at twice the volume. Although there is some disagreement, it is likely possible that you could fry your headunit if you crank the volume a lot.
2) You can leave the Bose amplifier in place and use a LLC (Line Level Converter) in between the headunit and the amplifier. This would convert the amplified signal sent out from your headunit into a line level signal that the Bose amplifier is designed to accept. You can also try without an LLC and simply hook it up, some have reported success doing this although it would not be considered a “clean” install and will not yield the best sound quality.
3) You could splice RCA connections onto the ends of the speaker wire pairs and connect them to your headunit’s RCA front and rear pre-outs if it has them. I don’t think anyone has actually tried this setup, although in theory it could work.
4) Ideally, you should replace all of the speakers and the headunit, and bypass the amplifier. I did this, and also removed my tweeters when I replaced the Bose Premium system in my 94 LS, the impact on sound quality from removing them is negligible and un-noticeable to most.
What are the extra connections plugged into my OEM headunit
Pre-wired CD Changer
This plug should already be connected to the back of your OEM deck, it runs all the way to the trunk. You can plug in any Alpine M-bus 6 disc CD changer, or you can use an adapter to connect an Ai-net 6 disc changer. You'll also need an Acura-Alpine adapter if you're adding a non-honda/acura changer to correct a difference in the cable's pinout. There is also an excellent DIY for making your own Custom Acura-Alpine adapter
Steering Wheel Controls
The one blue wire shown in the image interfaces the steering wheel controls. I believe those with the factory cell phone option might have other wires connected to this harness.
Rear Window Glass Antenna
This is the seconday antenna that consists of some wiring in your rear window that resembles the rear defroster, but is not connected to it. The OEM headunit will balance the signals between this and the regular mast antenna to give the best possible reception. The plug is smaller than a normal antenna plug.
How do I bypass the Bose amplifier?
Simply connect the wires before and after the amplifier using the following diagram (courtesy of Legend tuner). Crimp caps will work fine for making the connections, although soldering looks cleaner (I'll do that when I get around to it).
Harness A comes from the headunit.
A1 ----- Orange -------- Left Rear Speaker (+) ----- Connect to B2
A2 ----- Green --------- Left Rear Speaker (-) ------ Connect to B5
A3 ----- Yellow --------- Right Rear Speaker (+) ---- Connect to B1
A4 ----- Red ----------- Right Rear Speaker (-) ----- Connect to B3
A5 ----- Blue ----------- Right Front Speaker (+) --- Connect to C1
A6 ----- Brown --------- Right Front Speaker (-) ---- Connect to C4
A7 ----- White --------- Left Front Speaker (+) ----- Connect to C3
A8 ----- Black ---------- Left Front Speaker (-) ----- Connect to C7
A9-A15 ----------------- Not Used
A16 --- Yellow/White --- Turn on ------------------- Terminate
Harness B goes to the rear speakers.
B1 ----- Red/Yellow ---- Right Rear Speaker (+)
B2 ----- Blue/Yellow ---- Left Rear Speaker (+)
B3 ----- Brown --------- Right Rear Speaker (-)
B4 --------------------- Not Used
B5 ----- Gray ---------- Left Rear Speaker (-)
Harness C goes to the front speakers, power, and ground.
C1 ----- Red ------------ Right Front Speaker (+)
C2 ---------------------- Not Used
C3 ----- Blue ------------ Left Front Speaker (+)
C4 ----- Red/White ------ Right Front Speaker (-)
C5 ----- White/Blue ----- Constant Power
C6 ----- Black ----------- Ground
C7 ----- Blue/Orange ---- Left Front Speaker (-)
How do I add a subwoofer to the OEM system?
For any of the stock systems, you can tap the rear speaker wires and run them to your subwoofer's amplifier. If your amplifier has speaker level inputs, you can use them. If not, you can use a Line Level Converter (they cost about $10 online). You'll want one that has RCA outs (the most common type) to plug into your amplifier.
Please post any comments, suggestions, or corrections.