Originally Posted by blazeplacid

The stock head unit is ok for what it is. The signal it puts out is made for the speakers its driving from the factory.
Some people are happy with just upgrading the door speakers and some are happy with just replacing the tweeters. Its really up to you and how much you want to add.

A processor like the cleansweep basically cleans up the signal. Most (if not all) factory head units have some heavy equalization done so that the cheap factory speakers will sound their best. Not a bad thing for the people who like the factory sound set up. If you are wanting to upgrade that's where you might run into problems.

Like I said the sound is equalized for the factory speakers. When you add aftermarket speakers they may not sound their best because the head unit is sending out the equalized signal to the aftermarket speakers. To some people this is ok and they wont notice any change. Others can hear it and want to clean up the signal.

this is where a sound processor or DSP will help. You install the processor in line with the factory speaker wires.
The processor / DSP cleans up the signal so that you can add an amplifier with a nice clean an strong signal.

Most processors will give you a remote. Weather you use it or not is up to you. You can set up your processor and then disconnect the remote. This will allow you to control the volume from your steering wheel or head unit.
This also allows you to keep all the factory stuff like bluetooth (if your car has it) USB, XM, ipod.

hope that helped clarify a little bit

Originally Posted by gizmo134

Wait, so how do you have your bitten hooked up? to the line level wires from the headunit, or do you still have the stock amp?

Originally Posted by Absinthe

Hey Blaze,
I was under that impression as well until I ran across the post below. Still not buying into his test 100% I decided to swipe one of the Agilent spectrum Analyzers from work and do my own testing. Surprisingly enough, my results pretty much mimicked his. I compared the stock head unit to my older 2007 Alpine head unit and found the spectrum output differing by only a few db's. From this I have to conclude that pretty much all the eq work is done by the Bose amps. While I'm definitely in agreement regarding the necessity of a sound processor, I'm not inclined to recommend to anyone to look at a different head unit. Given the loss of the factory iPhone/iPod interfacing, navigation and voice command, its not worth the little added frequency response I might obtain.


The Art of JDM Sound - G37S Sedan Show/SQ install (170+pics) - G35Driver

Originally Posted by blazeplacid

not true

even the base audio has "eq'ing" done from the factory

I used a cheap line out put converter fist and the sound was.....

I hooked up the bit ten D and when running the software it noticed a lot of "eq'ing" . It cleaned it up and just from the initial factory settings the bit ten sounded tons better.

I do agree A DSP is the way to go instead of a cheap line out put converter.

Find a processor that fits your needs and budget.

Originally Posted by blazeplacid

The stock head unit is ok for what it is. The signal it puts out is made for the speakers its driving from the factory.
Some people are happy with just upgrading the door speakers and some are happy with just replacing the tweeters. Its really up to you and how much you want to add.

A processor like the cleansweep basically cleans up the signal. Most (if not all) factory head units have some heavy equalization done so that the cheap factory speakers will sound their best. Not a bad thing for the people who like the factory sound set up. If you are wanting to upgrade that's where you might run into problems.

Like I said the sound is equalized for the factory speakers. When you add aftermarket speakers they may not sound their best because the head unit is sending out the equalized signal to the aftermarket speakers. To some people this is ok and they wont notice any change. Others can hear it and want to clean up the signal.

this is where a sound processor or DSP will help. You install the processor in line with the factory speaker wires.
The processor / DSP cleans up the signal so that you can add an amplifier with a nice clean an strong signal.

Most processors will give you a remote. Weather you use it or not is up to you. You can set up your processor and then disconnect the remote. This will allow you to control the volume from your steering wheel or head unit.
This also allows you to keep all the factory stuff like bluetooth (if your car has it) USB, XM, ipod.

hope that helped clarify a little bit

Originally Posted by Absinthe

Hey Blaze,
I was under that impression as well until I ran across the post below. Still not buying into his test 100% I decided to swipe one of the Agilent spectrum Analyzers from work and do my own testing. Surprisingly enough, my results pretty much mimicked his. I compared the stock head unit to my older 2007 Alpine head unit and found the spectrum output differing by only a few db's. From this I have to conclude that pretty much all the eq work is done by the Bose amps. While I'm definitely in agreement regarding the necessity of a sound processor, I'm not inclined to recommend to anyone to look at a different head unit. Given the loss of the factory iPhone/iPod interfacing, navigation and voice command, its not worth the little added frequency response I might obtain.


The Art of JDM Sound - G37S Sedan Show/SQ install (170+pics) - G35Driver

Originally Posted by blazeplacid

I tied into the wires behind the radio.
My car doesnt have the bose but its the same.

You will want to tie into the wires behind the headunit to get a full range signal

Originally Posted by gizmo134

Hmm... now im wondering. With the Bose system, they run the full line level all the way to the trunk, and then run the speaker level from the trunk all around the car. I took the Bose amp apart and wired up a breakout, so that I have 4 line level RCA's and then all the speaker level wires right there. The bitone only (seems to, maybe im wrong) lets me do the anti-eq on speaker level, so on the line level i'm stuck. So does your radio only have speaker level outs comming out of it?

Originally Posted by dillyyo

IIRC, the signal voltage coming out of the Bose HU was between 4V or 5V, balanced. I spliced a Zapco Symblink cable into the signal wires and had a more than adequate signal feeding my Zapco amps. Can't remember if anyone scoped it, but i seem to recall the signal was clean through 7/8 of the volume continuum.

All I know is there is no need to lose audio functionality by replacing with an aftermarket HU and there is no need for a device such as cleansweep in the cars with Bose systems. Manville from JL stated himself, during a fourm discussion we were having, that the clean sweep would do nothing of value in this particular situation. The data out there clearly supports what Manville and others are saying.

Originally Posted by gizmo134

I've come to the conclusion that they must have changed things up between the different cars. My bit one will only do the anti-eq on the speaker level, so I think blaze is running speaker level, which would explain the un-flat signal. In the post about the build Absinthe referenced, the experience they had is that the HU only cut bass and treble, which again is different from my experience because it definitely will boost or cut either at the pre stock amp signals. The only reason I'm running the bit one is to do processing, doing 3 way fronts + subs, id rather have active eq'ing + crossovers. Harder to tune, but IMO better sounding in the end. If I was running regular speakers with passive xovers, I would stick with what you said. One note though, I know its balanced, and also not set at 0. Touch any of the = or - signal wires to ground, and you'll get a spark. Don't ask me how I figured that out.... haha

Originally Posted by Absinthe

Curious. When I was toiling in my trunk splicing those small wires, I did notice that each signal pair was bundled together with a shield that wrapped both the positive and negative signal wires. This shield disappeared back into the wire bundle. I checked the continuity to the vehidle chassis and there was none. The moment I broke the shield wire loose and broke the connection, I noticed a bit of hum from the speakers and also noticed some fade and slight popping after awhile. I never thought to measure the level of the shield wire to the vehicle chassis though.

Originally Posted by dillyyo

Clarification indeed; you refuse to acknowledge ignorance on this matter. I've seen it with my own eyes and the signal is flat. Maybe you are referring to the non-bose system, as I've heard processing occurs in the HU whereas the Bose system occurs in the amps. Nonetheless, your whole post is littered with inaccurate information and I suggest you research and learn something on the matter. It's out there.