jikman01

I have an alpine 9813 HU which has a 5 band parametric EQ and also a crossover feature.

Right now I have the stock speakers in the non-bose set up and I will be installing Infinity Kappa 62.5i 2-ways front and back. No sub, that's it.

Question is, how in the world do I set up my cross-over settings to get the best sound out of my set up?

I heard that you don't really want the same sound coming from all 4 speakers and that you should set your rears different than your fronts in the crossover. (I don't understand how to set this at all)

All I know is:

1) I can set the HPF cut-off frequency from 20Hz - 200Hz for my fronts and the also for the rears.

2) I have a slope setting for both front and rear that I can set for FLAT, -6, -12, -18, -24 dB/oct (whatever that means)

3) Then the LEVEL can be set from 0 to -12 dB.

As for the EQ I have the basic HU settings (Rock, Pop, News), but where do I learn how to tweak it myself if I have no idea what all the WIDTH, Frequency and band means??

Any help or direction is greatly appreciated!

peptidbond

iTrader: (2)

The only thing that I can offer is suggestions on the crossover setting. Leave it turned off if you are not going to add a sub. The reason is that you would be cutting out the sound that normally would be sent to a sub. However, since you have no sub, you would just be cutting out the bass.

Normally, you would set the crossover for about 150-200hz Highpass (everything above 200hz goes to the speakers). This would keep the bass out and the sound clean.

With your setup, I would leave the Xover turned off. If you later experience the speakers bottoming out (you will know when you hear it), turn the crossover on and set it for 50hz highpass. Slowly turn up the frequency until the speakers barely keep for bottoming out.

As for the Slope, it is a measurement of how quickly the crossover point acts. For example, you set your crossover at 200hz highpass with a slope of -12dB. This means that below 200Hz, the level of sound will decrease 12dB per octave. The Higher the setting, the faster the level will roll off below the crossover point.

As for the issue with bottoming out, again, set your crossover point to 50Hz highpass if you experience this issue. Then, set the slope to, say -12dB per octave. Now, see if the speakers still bottom out at the desired maximum volume. If so, try two things. First, switch the slope to -18dB per octave. Did this fix it? No, then switch the slope back to -12dB and start to raise the crossover point to 60, then 80 and so on until you get the right sound.

bastard

Set your high-pass filter (HPF) to 20-25 Hz (if it really will go that low) to remove bass you're not even going to hear anyway. This saves the amplifier in your headunit from powering really low notes for no reason and also removes some distortion from the speakers since they don't have to try to reproduce notes they can't really play anyway. Perfect human hearing is from 20-20,000 Hz. Most people hear a narrower range than that, say 25-30hz to 17k. This would cause the HPF to behave like an Infrasonic filter (an HPF that removes sound below human hearing)

For this situation, I'd probably set the crossover slope to the steepest one: 24dB/octave. Crossover slopes measure how quickly the crossover attenuates signals beyond the crossover point. Octaves are every doubling (or halving) of the frequency, so if you have middle C on a piano at 440 Hz, the next higher C is at 880 Hz. The next lower is at 220 Hz. A high-pass filter set at 440 Hz with the slope set to 24dB/oct would gradually attenuate the signal volume 24 dB by 220 Hz and 48dB by 110 Hz. A 12dB/oct slope would cut by 12dB at 220 hz and 24dB by 110.

Conversely, an LPF (low pass filter) set at the same frequency, 440 Hz, and same slope, 24dB/oct, would decrease the signal strength 24dB by 880 Hz, and 48dB by 1760 Hz. HPFs let music above the crossover point through, and LPFs let the lows through. Realize though that they do not cut all the signal past the crossover point through. They gradually mute the output depending on the slope.

These filters are mostly used if you have a subwoofer. This allows you to steer the bulk of the bass to the subwoofer and cut the lows out of the 6.5"s, and cut the mids and highs out of the sub and send them only to the 6.5"s. It seems that the Alpine setup is pretty versatile. A non subwoof'd system would lose a lot by cutting the bass out.

A note on this: In a subwoofered system, I'd highly recommend not setting the crossover points above 100ish. Much higher than that and some lower male voices (James Earl Jones? Peter Steele?) would be heard through the subwoofer and that sounds horrible. 80 Hz seems to be a good compromise: no voices and still cuts the bulk of the low bass out of the speakers that can't really handle it.

The parametric equalizer works on a similar principle except that it allows you to boost (or cut) a certain band centered on the EQ frequency. There's usually an adjustment called "Q" which is a number expressing the width of the affected band. Usually the smaller the number, the wider the band, if it's expressed as a Q value. I am not sure what the Alpines do. The level controls how much boost/cut is given to that band. The Z seems to have a pretty flat response curve except for a little brightness in the mids. I can't remember what frequency it is. Mostly the crossover is used to tune the sound to the user's preference. I'd recommend picking a preset (rock, pop, etc) that sounds good to you and playing with the equalizer until you get it right. The preset gives you a good baseline. Again, the Alpine setup looks to be flexible.

Hope this helps

Judge

I'm afraid I'm going to have to say Thank You Bastard!
Your reply is going to be promptly cut and pasted to my notepad of 'How A Stereo Works'. Up to this point I had no idea what all those things did.
Excellent post.