nope nope nope.

We aren't talking about how to get a nice linear sound out of the car, all we are talking about is how to make the tweeters less harsh. But f you want to talk about a linear sound, I digress;

In a perfect world I'd tell NightKids to do away with the passive crossovers, and run an active system, using two channels on the amp to run the midbass, and the other two channels to run the tweeters, that way he could simply turn the gains down on the tweeter channel in order to attenuate them.

However, without an understanding of the best way to tune a system like this, and without a headunit that supports running an active front stage, including a high pass filter above 1.5k Hz there is no point.

I think you are not fully understanding what a high pass filter/low pass filter is. It is simply a cut off point that stops frequencies above or below the point to not get through. But its not just this simple. It isnt just a line that the is the cutoff point. Its actually a roll off. So for each octave that goes past the point, it is lowered by a doubling amount.

So for example, if we are running a fully active setup, with all crossover points set on the headunit, and a sub, midbass and tweeter, we may have a low pass filter on the sub channel, set at 80Hz, and rolling off above that. Its called a low pass filter because it only lets through frequencies lower than the cut off point.

We would set the midbass high pass filter at about 100hz so that it only plays above that, and the low pass filter at about 1.5khz The tweeters would then play from 1.8kHz and upwards.

Because each set of drivers is now on its own channel, rather than using the EQ to set rough levels, we use the gains. So if we feel that the tweeters are a little harsh, we turn the gain down a little. If there isnt enough midbass, we turn that gain up.

From here, we can use the EQ to fine tune the setup. Personally, a 5 band EQ isnt quite enough, when i had a 3 way active setup, i had a 31 band parametric EQ through through an Alpine PXA-H701 processor.

You can use this to adjust particular frequencies in order to get a linear sound. For example, during judging in the MEASQ competition, there was a particular song that was used to listen for resonance at a certain frequency. If it sounded bad in other songs, it would be 10x worse during this song. The fix was as simple as pulling down 315Hz to about -6db, and the resonance was all but gone.

There was another song that was great for finding harshness in tweeters, as the thread is about. all you had to do was adjust the EQ around 1.8 to 2.2khz and it went from ear bleeding to sounding like an angel.

What we can do with the crossover points on the headunit/processor is adjust them to get the best out of the drivers. So i was using Boston Acoustics Pro60 which were known to be able to play down to about 60hz comfortably, which most others couldnt, so i had them play down to 60hz, and then cut off with a stepp 24db curve. I then had my RE Audio XXX play from 60Hz down to 20Hz.

Others may not be able to play this low, so they will need to utilise the points i listed above, with 80 and 100hz

Its all about experimentation, go out, sit in the car and just listen, and play with the settings.



But, back to the original question, and my original argument. all that NightKids needs to do is go to the EQ on his headunit, and turn down the highest EQ point until it doesnt sound so bad.