do factory systems automatically adjust music?

i recently upgraded my car's sound system. i did the head unit, speakers, added tweeters, subwoofers, and amps.. but i noticed that although it DOES sound better than before, my songs seem to be playing very inconsistently. for example, some songs seem to have too much bass and ends up drowning out the music while some songs tend to be too flat. the same with sharpness, some songs are perfect while others are either too sharp or not sharp enough even with the tweeters installed. i never had this problem with my factory system and compared it to other cars using the same CD (my 97 explorer's JBL, mom's 06 C280's harmon kardon LOGIC7, cousin's 99 camry's JBL, and a friend's 06 TSX) and all seem to come out consistent and all had one thing in common, they were all factory systems or factory options. the only ones that have the same problem as i do are the ones with aftermarket head units (e.g. my aftermarket JBL, brother's Jensen, friend's Pioneer and other friend's Kenwood).. and i remember reading up on JL Audio's "cleensweep" solution to factory systems in newer cars that feature a more integrated design and does not use a standard size or are not removable for aftermarket equipment and this got me wondering..

my question was if factory head units actually alter the music coming out of the speakers. i got my tweeters, amps + subs, speakers, and head unit all at different times.. but i only noticed the change after i switched out the head unit. if factory head units DO change the music, then is it possible to get something that will do the same with an aftermarket system? something like JL Audio's "cleensweep" solution, but backwards for aftermarket head units to get a more consistent music instead of "cleensweeping" a factory's altered music for aftermarket amps + subs.. please let me know what you guys think, thanks for any advice and sorry if it was a bit confusing..

mike

Cross overs would seperate the frequencies. Which might help

I think he's referring to how different songs are recorded with different acoustical properties, or how stations broadcast. For instance in my area, 101.9fm broadcasts a lot of bass and mild treble, so I have to adjust accordingly. Whereas 104.9fm plays the exact opposite and I have to adjust opposite. Then 105.7fm plays just fine and requires no adjustment.

His question is, do the headunits automatically adjust for this?

I think the answer is "No, they suck just enough that it levels itself out. Installing a new HU brings out those imperfections that the stock one got rid of due to its suckiness."

But he says that he compared different car vechile systems with the same song on the same cd.
Not saying your wrong but i dunno if that makes a difference.

Then mine still holds up. The stock unit coul just suck to the point that they bring the overpowered signals down to the level of everything else, whereas an aftermarket HU doesn't. Maybe it's meant that way, but I still think it's just because the stock HU's suck.

a stock stereo and speakers are designed to play all frequencies fairly uniform in volume over the useful frequency range of the speakers. And yes, some stock stereos do have some built-in equalization, especially the newer high-end cars.

When you change out the cd player and speakers, you will need to apply some equalization. What is happening is there are peaks and dips in your frequency response, not all music plays ALL the frequencies all the time. When it hits a dip it sounds lower, when it hits a peak it sounds louder.

thanks for all the help IcESouL, Jet-Lee, and PaulD.. so, just to clarify it up, some of the factory head units DO adjust the music? yeah, my explorer's factory "premium" JBL wasn't premium at all, it really DID suck.. probably to the point where everything came out crap just like you said, Jet-Lee.. but some of the other factory ones i tried it on (e.g. Camry's JBL, C280's Harmon Kardon LOGIC7) were VERY nice systems, especially on the C280.. and yet they still play all the different songs very consistently as PaulD mentioned.. as far as higher-end cars adjusting my CD's songs automatically, i could believe that on the C280 cuz it was an expensive factory option, but the camry and explorer's JBL are 99 and 97 respectively.. the explorer's JBL just plain sucks so i'm throwing that out of consideration, but the camry's JBL was exceptional and exceeded my expectations for a 99 factory system, yet i would still find it hard to believe that it could adjust my CD the same way the C280's expensive system did..

i did adjust the equalizer on my new head unit (took me a while to get it at a compromise) but some of my songs still play with bass that drowns out the music or highs that are to an ear-piercing sharpness, just nothing to an extreme of how it was before when i first installed it and left it at a preset equalizer setting. so right now, is there something i could buy or something i could do to makes these extreme differences a little less severe? or is there no other way but for me to continue using CD-RWs to reburn songs that are pre-edited on the computer after an initial burn and test play?

thanks again :)
Michael Ni

you will need to use a real time analyzer (RTA) and a CD with pink noise to really "see" and tame those freq resp dragons.

you will need to use a real time analyzer (RTA) and a CD with pink noise to really "see" and tame those freq resp dragons.

thanks, i'll definitely look into that..

Mike