2008 M35-S Sound System Install

[SimonSaysM35]

Hey guys, Im new here!

I got my 08 M35-S back in October, I aslo still had my honda at that time. Im about to get rid of the Accord and took out my whole stereo system.

How easy is it to install a sound system in my M35? Im too scared to mess with the electrical or mess up the quality. In the honda, i used to crawl all around in there and do whatever, but Im worried now

How much can the stock speakers take? Can i leave the OEM console in?

I was planning on installing (from the honda to the m35) 2 JL 13.5' W3's in custom box, JL 500/1 amp, and JL 300/4 amp....is it even worth it?

I appreciate all the help!

[EniGmA1987]

Well the problem is the system is all integrated into a Bose proprietary unit. Other people have much more knowledge about how to go about changing things, but the general consensus is that you should replace the tweeters and the sub. However, for the sub you will need to get the signal from some place else and apply a crossover to the split signal going to the sub amp to get only the frequencies you want. The reason for this is that the Bose system seems to turn down the sub volume as system volume is increased.

I have yet to see any proof of that claim, and I find it pretty hard to believe actually. Here is my theory which is WAY more scientifically accurate, although I still have no actual proof of it. My theory is simply that the sucky Bose amp cannot adequately power the stock sub. The efficiency on the sub is much lower than other speakers in the system. Thus as you turn the volume up, the amp maxes out on its power capability and cannot push the sub as hard as it needs to be to keep up with the rest of the system. The human ear cannot hear the lower frequencies as well as the higher ones, so volume in the very low range must be up higher for us to perceive it easier. Plus, the sub is in the back which is farther from us. SO it needs to be pushed harder relative to the volume of the front speakers in order to perceive it in proper balance to the rest of the system. If the amp tops out and only is able to push exponentially smaller amounts of power for each turn you crank up the volume in comparison to the other speakers, the volume we perceive seems to be going down as the other volume goes up. I hope I explained that well enough, its hard for me to put things into words.


Oh, and you cannot disconnect the sub amp from the system. You must have it running and your other amp. The stock sub amp also powers something else in the car. I forget what, but I remember that it is NEEDED.

[Ilya]

About the sub...

I actually chatted with a Crutchfield support person called Greg and here is what he said (regarding my 8 speaker system):

Door speakers are 2-ohm. He recommended I get the Infinity Reference 6032si. I intend to get 2 sets of these for the front and rear doors.

For the center channel (on the dash) - the speaker size is 3" but he says if it's working I shouldn't mess with it as that size is hard to find and they are only sold in pairs (we only have one).

I won't be touching the tweeters just yet. I just want some more bass.

Now, as for the subwoofer he said:

06/14/2010 03:36:29PM Agent (Greg.): "There is some custom work involved. First off, you need to drill new screw holes for the new sub in the rear deck. We also need to find a sub that matches the impedance of the factory sub. Then for the front door tweeters, there needs to be brackets made in order for the new tweeters to sit in that factory location."
06/14/2010 03:48:42PM Agent (Greg.): "As far as the subwoofer in the back goes, your best bet is going to be the Alpine SWS-1023D which has that dual 2 ohm design that we need:"
06/14/2010 03:48:49PM Agent (Greg.): "http://www.crutchfield.com/cgi-bin/Prod ... 500SWS1023"
06/14/2010 03:49:21PM Ilya: "Do you think that will fit in the stock enclosure?"
06/14/2010 03:49:31PM Ilya: "I'm thinkin real estate is limited"
06/14/2010 03:51:59PM Agent (Greg.): "Actually, there is 8" of depth to work with plus 9.6" of cutout diameter. So that Alpine will indeed fit."
06/14/2010 03:52:18PM Ilya: "Awesome"
06/14/2010 03:52:47PM Ilya: "And I won't need an extra amp to run it? I read somewhere that one guy had to put an amp inbetween the stock amp and the after market sub because the sub sounded like crap without the added amp. Is that because he didn't match impedence?"
06/14/2010 03:57:07PM Ilya: "And is there anything else I need for this swap? Or just speaker wire?"
06/14/2010 03:57:38PM Agent (Greg.): "Exactly. You can still use the factory Bose amp. You really don't have to swap anything. You can use the factory wires. You do have to cut the factory connectors off and hardwire directly to the speakers and sub but nothing else has to be done."
06/14/2010 03:58:42PM Ilya: "Suhweet."
06/14/2010 03:58:54PM Ilya: "So the only thing left is to just figure out the mounting? Correct?"
06/14/2010 03:59:32PM Agent (Greg.): "That's about it actually."
06/14/2010 03:59:42PM Ilya: "Alright. Awesome."
06/14/2010 04:00:29PM Ilya: "For under $300, that's actually quite good. Thank you for your help."

[EniGmA1987]

The sub that you talked about doing has nothing to do with what the OP is going to do though. He is using "real" subwoofers in a custom enclosure with a "real" amplifier. The impedance doesnt matter at all as long as the amp is capable of handling the load. You need to look at efficiency and amplifier power to see if you can use a sub or not. Matching impedance means nothing for a sub in the end.

Example:
If the stock sub is 1ohm nominal and has 83db efficiency, you could put a 2ohm sub in there as a replacement with 89db efficiency and the replacement sub would be able to put out higher volume with cleaner sound than the stock 1ohm sub. Because at 89 decibels of sound pressure output from the stock sub, it would be using 4 watts of power while the replacement would only be using 1 watt of power at the same SPL. Yes the amp theoretically has only half the max output power, but the replacement would still get higher volume. Lets say the max power from the stock system is 50w, the stock sub would reach that 50w (assuming a randomly thought up 83db efficiency) around 100 decibels. The theoretical 2ohm replacement sub would max out the amps power somewhere around 103 decibels. Again, this is all theoretical, it is just an example of how impedance matching doesn't mean anything as long as the amp is capable of driving the load that the subwoofer places on it. Either way, the Bose amp is pretty sucky and should be bypassed if you are doing anything aftermarket with your sound system.



I am making up numbers for how much power the subwoofer has in the stock system because I honestly dont know how much it can put out. I do know that the highest 14-speaker Bose system has a total wattage of 308w. The 8-speaker system uses 234 watts max. And the unbranded 6-speaker system has 160w max.

Do the math, split evenly the 14-speaker system only gives 22w to each speaker. Now the sub gets a lot more than the other speakers, but at most your looking at 70w or so for the sub. And if thats the case, the other speakers are limited to 18w max. Again, theoretical. But Im just saying, the power the speakers get at stock it pitiful.




EDIT: As for the last poster, you had better pray this guy you talked to knows more than it seems from that conversation. I have a feeling he knows absolutely nothing about the system in your car, and IF your factory amp is not capable of handling dips to as low as 0.5 ohms, or your replacement sub with its dual voice coils drawing power at the same time try to draw too much from the amp, then you can seriously damage your system. and then youll be out $3000 or so to get it replaced. which wont be covered under warranty or insurance since you damaged it yourself with that aftermarket stuff. Do some additional research before you go ahead wth what he says.

[Ilya]

Oh my bad. I misread what he was trying to do. On a side note now that you mention impedence and all that jazz, did the Crutchfield guy feed me a buncha crap? PM me if you want (as to not take this further off topic).

[EniGmA1987]

Ok I remembered why you cannot completely remove the stock Bose amp. It powers the voice for your navigation, as well as turns down the audio volume when the voice is talking. It powers all voice things, so when you push the "talk" button and the car says "please say command" you wont hear the car talking at all anymore if you were to remove the Bose amp.


Also to the OP, you need a unit like this:
http://www.crutchfield.com/p_236REQ/MTX ... ailed_info

To take the signal that goes to the factory sub and convert it to a line level signal that you can feed into that JL amp that is going to power your new sub.

[SimonSaysM35]

wow guys, extremely useful information. I appreciate all your help and input. Thanks!