ive looked through the other threads, and im not sure if this is gonna be considered a repost, but i think ive found a way to add an amp, in easy to understand terms(5 channel, probably applies for any number of channels, but this write-up is specific to a fiver) to the stock system easily. If im wrong anywhere here, please let me know so it can be changed, and if its right maybe this can be a sticky or something . Anyways, here it goes

Okay, here it goes. You'll need to buy a NE-774V LOC or any 4 channel LOC.
BEWARE
Im basing the rest of this on the premise that the stock set up sends full range frequency to the speakers, (except for the tweeters which get the highest freqs. and the subs [6x9s] that get the lowest freqs.. In which case would the following be the best setup to do?) then I can take the signals/wires from the F pass. door, F driver door, L rear door, and R rear door connect them to the LOC which the has the RCA connectors on the other side. (im not sure if its male or female, cause i never learned which was which, but its the one with the hole, so i guess its female). then, i just get two sets of RCAs one set for the L&R Rear speakers, and one set for the L&R Front speakers.
The only question this brings up is how it would go into the amp, because the LOC divides the RCA's into: Front Left and Front Right; Rear Right and Rear Left. Does the amp do channels by Front and Rear? to my knowledge i thought it was Left and Right..?

But if this LOC works, and this is a good sound quality way to go, then I'm basically all set then right? Is this how it would end up looking? (in no particular order, i dont know if order matters though)

1 Channel: speaker wire to the L xover, then from there, speaker wire to L woofer & tweeter
2 Channel: speaker wire to the R xover, then from there, speaker wire to the R woofer & tweeter
3 Channel: speaker wire to L sub?
4 Channel: speaker wire to R sub?
5 Channel: ??? not used ???

 

using the information e_lectro found about the speaker wiring colors and such, i think that this could be a pretty easy thing to do. the only bad part will be the physical wiring and hiding and xover placement and getting to the tweeters and front doors

 

heres a picture i drew up of what it'd look like, minus the wiring to the speakers

 

isn't it possible or even better to just bypass the stock amp or am i missing something?

 

im pretty positive its possible, the only thing i dont know about is the signals the head unit is sending out on each wire. and i think that if you did bypass the stock amp, it would be the same setup. as for being better, it could very possibly be better as well for sound quality, this write-up is pretty much aimed toward people like me whos knowledge on this stuff is very limited. cause if you end up getting any extraneous and unwanted noise by bypassing the stock amp, i wouldnt be in a position to really approach it.
my understanding of all of this is VERY limited, as you can see, i even have questions in it! haha...
so this thread is more of me having done some research and thinking and coming to a, hopefully for the most part correct, conclusion on how to solve this riddle. id rather do the install myself seeing how i already know this much more than the installer working on my car. so those of you that are more audio savvy than i, please confirm whether or not what i posted can be done...
hope i answered your question

 

Your setup looks alot like what I did.

I wanted to bypass the factory amp into a 4 channel aftermarket, and then drive the front and rear speakers. Due to issues with this wiring set-up, the installer chose to instead take the signals from the speakers (out of the stock amp) and run them through LOC's into the new amp.

At mid to high volume the sound is great, but at low volume I get a lot of hiss. I have dropped the gain on the amp to reduce the hiss, but then the high volume sucks. I am going to meet with another installer today who is more familiar with the TSX to debug and tune it a little. In playing around I learned that most of the noise is coming in from one channel. This points to a poor wiring job or a dud LOC.

When I have more info I will follow up.

 

Somehow I missed this while traveling... but the HU has standard preamp out, and your installer F'd up, and no LOC's are needed.

 

no no no, this hasnt happened yet. this is just me brainstorming an idea and seeing if its correct or not.

 

Yea, I figured the installer screwed up. He told me at first that he couldn't bypass the factory amp because it shut the entire HVAC system down.
I later found out he didn't bypass the factory amp because he didn't have a wiring diagram for the HU.
Now I have a system that takes the speaker outputs from the factory amp into a LOC, and then into my new amp. Overall it doesn't sound bad, but it is not nearly as clean as I would like. When I get time I am going to open the front up and take the signal straight from the HU.

 

There are a number of threads which describe the preamp OP of the HU at the factory amp (below the NOT AN ASHTRAY).

The HU has F and R full-range preamp OP, standard (not high, high=4V) output level, single-ended unbalanced.

No amp adapter harness is available at present as far as I know. You may want a line driver - turning the amp gains up often results in noise not audible with low gain settings.

The remote turn on output of the HU works whenever the HU is on, and is 12V (+).

 

As far as noise goes, I don't think using the HU can make it any worse than my current set up. I have the gain turned way down. It sounds okay at higher volume (before the HU starts to clip). At lower volume (even zero) I get alot of hiss. It is a balance of gain vs noise. The more gain I add, the more hiss I get. All I want is a system that sounds clean at low volume, with a rich clean sound at high volume. I have pulled the HU wiring diagram already, it is just a case of getting the time to do it.

 

line driver

 

IN my car the HU never clips.

Based on your setup, I think the input of the LOC is your problem. The OE amp is exceeding the input capability of the LOC.

I have my F gain at minimum, and at 40, I have clean sound and no hiss or clipping. With some CD's, I can flap my 6x9's, and vito corleone's solution of high-passing them is under consideration. My system is loud enough to listen to with the sunroof open and the windows down, something I didn't have before.

Often we associate volume with distortion. When you have clean sound and little distortion, you may not thnk it's that loud at first... till you turn it off, or try to talk over it. Common experience.

Make sure to avoid the Airbag ECU with the Yellow wires coming out of it, forward of the OE amp. It's an EMI noise emitter.

 

I need to make another appointment and have my install checked because I'm getting some alternator whine - but, then, it was there even in the stock system... it's just worse now. Zero hiss, however. And with volume, the whine is inaudible.

Enabling an HP on the 6x9's - for people that don't install quality 6.5"s up front that have a solid low end, I don't know that I'd recommend it since you'd lose some low-mid punch. For those that have (elduderino), I just recently adjusted the HP filter down a little to 90 or a bit above because I found the bass to be a bit "plonky" sounding at times when it was set to 100Hz. Since the amp is doing the HP filtering, it's only at 12db/oct. If it was 24db/oct I suppose there's a good chance I wouldn't have had to adjust it down. In conjunction with a 24db/oct LP filter at 50, the MBQ Ref 6x9's can really pound (sometimes too much, so I might have to adjust the gain down a touch, which sucks because the custom amp cover is hard to get back on).

I had brought in a print out of every diagram of the TSX stereo wiring I could find on this site, just in case the installer hadn't worked on a TSX - or worked on one as extensively. He found it kind of amusing, but I didn't care because the TSX is my precious. Heh.

 

Vito, I think you have the HP and LP abbreviations backwards. High pass takes out lows and passes highs, low pass takes out highs and passes lows. So F speaks get a HP and woofs get a LP, and band-passed woofs get a LP and a very-low-setting HP as a "subsonic filter".

I would try a high-pass of 40 on the by-nines if you can go that low. I was considering an amp with a subsonic filter for that reason, but it didn't fit.

I have a low-pass to mine of 75... I don't have a high-pass to them right now... I wish I could get 24dB at 35 or 12dB at 40... and I totally agree that if they go very high the sound is not as good (I think the mids get too loud!)

I use my F and R outputs from the HU to the amp, and then use the R OP as the woofer level control on the fly. Setting it 1 click forward takes care of any overpowering bass that tries to stress the 6x9s.

Two items to think about:

1) I had noise on my F channels unless the F gain was at minimum. I was testing with a zero-bits disc, so volume was not an issue. When I tested with a music CD, I had plenty of volume with the F amp gain at minimum, so I simply quit and set it there. See if that makes a diff for you. If it does, but you lack needed volume, then a line driver might be it. I would use the OE amp ground for the line driver.

2) Yeah, lots of installers can't read, so they have attitude. I loved it when people brought in diagrams. Many installers can't use them, though.

3) It's easy to forget that the response of the xover has to be added to the response of the speaker to get the actual output. If the speaker gets louder from 90 to 700 (not unheard of in a small woofer), then the xover is not removing this sound, simply quieting it at 12dB per octave (12dB quieter at 180, 24dB quieter at 360 - less, but audible!). Another reason for 4th-order filtering.

 

Clipping was a bad choice of words. It is more of a muddy sound above 30. Either way, it isn't a clean sound. I have played with the LOC level and the gain on the amp to get it as good as possible.

When I have changed the input to the HU I will let you know how different it sounds.

 

Cool. I am confident you will get a great sonic improvement. The HU itself is clean up to 40!