Hi all, I am trying to figure out why the Harman-Kardon stereo in the C55 sounds so bad. The mid-range and vocals, which can be described as a muddy, subdued and cold, basically hides in the background. The weak bass note which lacks body and gets boomy rather than punchy when you turn up the bass level or the volume. The treble, like the mid-range lacks definition, and gets metallic and hissy rather than more distinct if you crank it up. This is ABSOLUTELY the worst premium car stereo setup I have ever experienced. Even the $99 Creative Labs T20 2-way, 2.0-channel, sub-less 14 watt computer speaker on my desk sounds better!!!

Complaining, however, doesn't solve the problem; I need to know why. I have a theory, but to verify it I am appealing to all of you for more information with regard to this POS. More specifically, I'll like to know what the speaker impedances are and more importantly what the amplifier's output impedance is. The latter, MUCH more than the power rating, can be key to how the setup sounds. Especially when paired with low impedance speakers. My suspicion is that the damping factor (ratio of the speaker impedance over amp output impedance) is less than 10~15. Because if this is true it'll cause EXACTLY the symptoms described above. Further more, if this is true, anyone who changes the amplifier will see a huge difference in sound whereas if they change speakers (especially to ones with equal or similar impedance to the factory ones) they'll see little or no improvement!

People like to talk about how many watts their amps are and what the power handling rating of their speakers are. But unless your concept of good sound defined by specific pressure levels, that is probably the LEAST important aspect of a stereo setup. Probably what makes the most difference is the damping factor; even more than THD. Without going into all the mathematical models and logarithmic complex roots, let's just say that a high amplifier output impedance diminishes the speaker's frequency response and the amplifier's ability to control the motion of the speaker cone. The former causes the speaker to sound "dead" and lethargic, the latter causes the amplifier to lose control of the speaker cone causes the sound to be muddy and messy. This is why 4 ohm speakers are so hard to drive -- you can have 500 watt rms monobloc amps and if the output impedance is high it still sounds like crap, whereas the high current / low impedance amp designs (like the NAIMs) sound so wonderful despite very modest power ratings. And, I'll also say this... BOSE stuff sucks in most respects, but one thing they usually do right is have good damping factors! That, along with the artificial mid-range separation and higher than normal sub-woofer crossover frequency nonsense that they pull, means that while their stuff may sound as synthetic as Mobil 1 oil they at least always sound alive and punchy.

 

I too think the HK system in my car sucks. My girlfriends Nissan Altima blows this stereo away. I'm no car stereo guy, but there is a thread that claims adding aftermarket amp to to the stock system made it sound better. Honestly I think this thread is long over due. I will be waiting with you to see what others say.

 

I added an aftermarket amp(as well as a head unit) and it sounds much better! You can get a decent amp for a few hundred bucks and it will bring alot more volume to the system.

 

really? Do you have Nav? I wonder if you can add an amp to the stock comand head unit. I know nothing about car audio.

 

yup i had the full nav/comand unit..... you should be able to add an amp and keep the head unit stock. you can also get an aftermarket head unit(with ipod, bluetooth and better navigation) and sell the stock nav unit on ebay for about $500

 

Any recommendations for a light weight amp? How may watts should i get?

 

Heres are the solutions...

Remove your resonator...If that doens't help, ur primary, secondary cats..


Problem solved.


Happy new year!

 

Please do share some pics of ur set up!

Thanks