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Factory Door Speaker Alternative Fix

Joined
11 June 2015
Messages
346
Location
Los Altos, CA
The factory door speakers had been bad on my 91 when I bought her, and I finally got around to fixing everything. I did not want to find used factory speakers that may fail again some day and may be even harder to find, so I decided to go with the following approach:

- SOS Door Speaker Adapter Kit
- Pioneer 6.5" component speakers

The problem with this, is that the factory door speakers had an integrated amp that I now needed to replace. I wanted to avoid having to mount an amp somewhere visible in the car and running wiring all over the place. That led me to the below solution:

- Alpine KTP-445U Power Pack

The power pack actually fits perfectly behind the center console under the climate control unit, so I was able to avoid having to install an amp in the truck and run all of that wiring... I'm very happy with the sound and the fact that the doors now support universal component speakers for the future.

Just wanted to share my experiences in case anyone finds themselves heading down the same road in the future.

Cheers!
 
FYI, you can also purchase new units directly from Bose for about 150 per speaker. [MENTION=30518]Speedmaster[/MENTION] did a public service announcement on the topic. But glad you found a good solution. I run the Alpine type r components and they are loud as hell.
 
Did u remove the footwell sub?
Were u able to use existing wires or did u ran new?
 
Can you explain more in detail on what you did? I wouldn't mind running aftermarket units in mine.
 
As a reminder, the OEM BOSE system in the NSX uses 3 'distributed' amps .. one in each door integrated with the speaker, and one in the footwell sub enclosure. The head unit only outputs line-level voltage signals .. not speaker level. This unit is primarily intended to boost the outputs of a head unit that has a built in amp and is already outputting speaker levels. However, it says it has options to select whether the inputs are RCA level or speaker level and the 150% increase that it claims is consistent with a boost from 0.2-4.0 V (RCA) to 0.4-10 V speaker levels. Remember that the designers would have only spec'd the 'head-to-door' wiring for RCA level voltages and you're now going to be pushing as much as 2.5x as much current thru that wiring if the replacement speakers have the same impedance as OEM. However, IIRC the OEM speakers are very low impedance .. maybe as low as 2 ohms so if the replacement speakers are 4 ohm, for example, the increased current will be negligible. Others on Prime have attempted in the past to rewire through the door with not a lot of success. The existing door wiring also has an additional wire for +12 V that is needed to power the BOSE door amps.

The sub may be a different story depending on your approach. The amp in the sub takes the left and right channels; merges them; amplifies that and sends it to the single rear speaker on the center of the bulkhead by your right elbow. It also takes the merged signal; strips out the higher frequencies; and then amplifies it for the sub. In the case of the door amps, you're throwing them away and it's no big deal because you're using the boost from this power pack. But if you throw the sub amp away, you lose the ability to drive the rear speaker (some don't even know there's one there) and you loose a proper sub signal. In home stereo systems, you usually set your sub to only react to frequencies below a certain threshold .. and the OEM sub amp is doing this for you and if you throw it away, it's going to try to reproduce all freq and likely not work well.
 
FYI, you can also purchase new units directly from Bose for about 150 per speaker. @Speedmaster did a public service announcement on the topic. But glad you found a good solution. I run the Alpine type r components and they are loud as hell.

I did not know that! Either way, I'm happy that ive got a universal setup moving forward. There will likely be a day in the future that there is no more support for these speakers.
 
Did u remove the footwell sub?
Were u able to use existing wires or did u ran new?

Nope, kept the sub and center speaker, as they run off of their own amp. Just installed the amp for the two door speakers. I did not run wires, but I'm thinking someone before me may have, because they are in a shielded 2-wire cable. If it is aftermarket, they did a hell of a job running it through the doors and along the factory harness back to the head, because there is no evidence of it.
 
B2FiNiTy - I basically installed a 2-channel amp between the head and the door speakers, with universal speakers in the door. This was necessary because the factory door speakers have integrated amps.

NSX2398 - I left the sub and center speaker, they are operating perfectly. I just installed the amp for the door speakers, and they are 4 ohm, so it should be fine, but that's a good thought. Would you happen to know if the factory head-to-door wiring is individual wires, or a shielded pair?
 
NSX2398 - I left the sub and center speaker, they are operating perfectly. I just installed the amp for the door speakers, and they are 4 ohm, so it should be fine, but that's a good thought. Would you happen to know if the factory head-to-door wiring is individual wires, or a shielded pair?
I'm not near my shop manual with the wiring diagrams at the moment .. but going from memory, I'm pretty sure they had dotted lines on the head-to-door wiring indicating that they were shielded.
 
I'm not near my shop manual with the wiring diagrams at the moment .. but going from memory, I'm pretty sure they had dotted lines on the head-to-door wiring indicating that they were shielded.

Ok so it's probably factory. I would have been surprised at how well of a job they did if it was aftermarket!
 
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