Harmon Frequency Response

[DCMINICOOPER]

I did some frequency response measurements this weekend on my 2004 mini with the Harmon upgrade. Overall, the measured frequency response is very uneven, and cannot be equalized with the tone controls or other settings. It seems a full signal is being applied to the front in all modes. There is also a sudden dropoff of about 10 db that begins about 600 hz in all modes. This can't be fixed since the bass controls are only effective from about 150 hz on down. I am considering trying to cut the bass response to the front below 600 hz (using bass blockers or similar) to help flatten out the system. Anyone else take similar measurements or have any ideas on improving this systems performance. In general, I think the bass is very muddy, and the measurements re-inforce what I am hearing.

Right now, the best response seems to be in the HK mode with bass almost all the way down. I plan on some more testing later this week using a db meter and a test cd. Has anyone had the system professionally analyzed using a spectrum analyzer?

[GBMINI]

What mode is selected? Some of the HK modes (electronic) have very different emphasis to others (I use spatial).
How are you measuring - I presume the frequency response is tuned to some extent to compensate for the "audio shape" of the MINI ...

If you go to MCOL you can find quite a lot about HK - in particular search for posts by "tacotim".

[DCMINICOOPER]

I tried all modes and there is still a big dip in response around 6oo HZ all the way up (or a boast below 600 hz however you look at it). The problem is that the tone controls are ineffective above 150hz (bass) to 4khz (treble). The main difference in modes seems to be the amount of bass boast and how much of the signal is fed to the rear. I didn't compensate for the mini itself as I assumed that the HK system would include equalization if the system was really tuned for the vehicle. I have taken similar measurements in my other vehicles was able to achieve a much flatter response.

[GBMINI]

I think tacotim said something about the HK boosting low frequency to (fool the ears?) compensate for no subs and their really low frequency ...
That is what I miss in my MINI now - the really low frequency stuff that you almost feel instead of hear. The HK puts out (for me) quite clear music with a good range, but after hearing a friends car, I know there is stuff missing below maybe 80Hz.
My HU allows me to move the bass center frequency - if I set it to 60Hz then it has very little effect on sound, so I guess the HK has a cutoff down there ...

[DCMINICOOPER]

How did you move the center frequency. I haven't found such a control. Also, I measured good response down to 40HZ, after which it drops off significantly.

[GBMINI]

Interesting that you measured down to 40Hz - good!
My HU is aftermarket (Kenwood) with lots of adjustments.