Hey,

What are the normal causes of distortion in the higher frequencies.

I have noticed that at certain frequencies there is a noticable amount of distortion coming through the tweeters (dynaudio MD100). The notes themselves are clear but there is distorted static sound underlying the sound.

I tried changing amps to see if that was the problem but the distorition remains even with different amps.
I dont think its is induced noise either as i cant hear any noise if i press pause and crank the volume.

what could this be, its driving me isnsane!

Thanks
Adrian

it may be an issues that an eq may solve, in the extreme high end my supremos need a little bit of a tone down.

possibly, but the frequencies that seem to have distortion are not the extreme high frequencies, they seem to be at the lower end of the 'high frequencies. :?

Don't quote me on this but I think its just your ears (ears distorting not speakers). I first experienced this high frequency distortion at a tool concert when the vocals started to distort heaps... or atleast thats what I thought

If you hit pause when you first notice the distortion, notice that your ears are ringing quite substantially. I think its because your ears are the most sensitive around these frequencies (about 5kHz), and when the output matches the natural frequencies (resonant frequencies) of the little bones inside you ears huge energies are transferred.

If this is what it is (it might not be), try tuning down the frequency bands near 5kHz down to stop ear distortion

Although my ears do ring sometimes, this problem is definately not attributable to them as i have shown other people and they too can hear it. That tool concert was the loudest concert ever! :shock: i went also, awesome.

anyway I just cant figure this one out... :?

has anyone else had this problem?

do you think it could be a problem with the head unit. It is a 6450 that is due for update.

I had a very similar problem - it turned out to be amp induced noise which only appeard when bridging the amp. However since you have swapped amps i doubt that si your problem.

However it could still be "induced noise" from your headunit. As the pause test isn't always effective with units that have a zero bit mute etc. I'd also be investigating your cabling.

hey I just thought of a good test for the ear thing (I know you've probably already discarded it as the cause of your problem).

1)Turn the music up to the volume where the distortion is clear
2)Get out of the car, but leave the door/s open so the tweets are facing outwards
3)Take a few steps away from the car

This will mean keeping the speakers at the same spl, but reducing their APPARENT volume. If clarity improves (ie. distortion is replaced by clear sound) after you take a few steps away from the car its an ear problem. If not....ask someone who has a better technical knowledge than I.

not a bad idea man.

however, the distrotion is apparent at low volumes as well.

Cheers anyway

Are you using the norman crossovers? You can get a bit of distortion from using a crossover point which is too high, but if you're using the Dyn ones, then i'd put it down to either your amp settings or speaker placement. They're not reflecting off the glass are they?

It wouldn't surprise me if it was a flaw in the actual recording.

Tuneman will back me uop on this one.

A lot of the CD's we have in Australia are crape compared to the same CD say in the USA.

I think some of the pressing companies in Australia seem to stuff it up along the way.

Norah Jones or Evanescence for exmple are both crape CDs if you buy them in Australia.
The Same CDs in the US are fine.
(From what I have been told by SQ guys on the forums over there)

the tweeters are mounted in pods on the a-pillars, so there probably is some degree of reflection but, this doesnt appear to be a reflection type sound. amp settings for the dyns are HP at about 100Hz.

The crossovers i am using are the standard dyn ones.

I did contemplate the CD quality, but why would the distortion only be happening in such a narrow frequency range, only in the lower frequencies that the tweeters play?

Hmm, cant really say on that one.

However both Tuneman and myself generally have experienced the same thing with certain tracks.

We both have compresion horns for our front end which really show detail in music well.

You can put the same disc into both cars and get the same "glitches" at the same point in time on the track.

We both have different decks, amps and horns and the same "glitches" show up on the same recordings.

Well assuming nothing is being overdriven (amp or tweeter, or crossover)...
It is likely that you are hearing a peak in the upper midrange or treble, likely due to reflections (remember that reflections in treble range may not neccesarily sound quite like you think, due to the very short wavelengths) . I would recommend playing with the angle of the tweeter if possible - how are the tweeters angled now.