Why do my mids/highs sound like crap?

[Krazykid122]

I have 2 Rockford Fosgate Power 6x8s with the tweeters removed in the front door, 2 Polk Audio DXi Series 6x8s in the back doors and 2 Alpine tweeters on the A-Pillar. For a while i had noticed at high volumes my music would get kind of muffled, or atleast the higher frequencies would. Mostly in my doors, i would be driving, playing my music, then i could hear the words and bass, but all the higher notes would fade away and it would sound as if i had a PA Horn for mids/highs. I turn down the volume for just alittle bit, not all the way about 1/4 or alittle more and the sound would come back. My tweeters were on HU power untill yesterday, moved them to channel 1-2 on the Rockford 400-4, and the 4 6x8s on channel 3-4. I still have the same problem except its way more noticeable because the tweeters do it now also, they may have before but they were not loud enough to be able to tell. The HPF is all the way up on the amp (500Hz iirc), and the tweeters have 14.5uF caps on them, not sure if there still getting to low of a freq. Also i have blown a cap on one of my polks twice, same cap, same speaker, its one of the caps going to the tweeter, im not sure if thats a bad sign of overpower/distortion.

I am not sure what this is and it makes my system sound like garbage, im tired of spending money and having shit sound with halfway decent equipment, when people run around with there 4 Q power door speakers and boss 4 channel and theirs is better than mine.

Only thing i can think of would be voltage drop causing distortion? My voltage will get to the low 11s sometimes hell ive seen 10.8 at the front battery, no telling how bad it is in the back.

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Do you have any electical upgrades?

[Krazykid122]

Do you have any electical upgrades?

Everything but an alternator

[Guest]

at 4 ohms, 2750hz at 6db (not that steep...) is 14.46 microfarads.

tweets should be at like 3-4k, depending on the model/brand/type.

didnt those alpine tweeters come with their own crossover?

[Krazykid122]

at 4 ohms, 2750hz at 6db (not that steep...) is 14.46 microfarads.

tweets should be at like 3-4k, depending on the model/brand/type.

didnt those alpine tweeters come with their own crossover?

They did not unless there little caps built in to them, im a little confused on what you meant by "at 4 ohms, 2750hz at 6db (not that steep...) is 14.46 microfarads."

Here are the tweets and amp.

http://www.sonicelectronix.com/item_36_Alpine-SPS-1005.html

http://www.sonicelectronix.com/item_9102_Rockford-Fosgate-Power-T400-4.html

"edit" The tweeters are on channel 1 and 2, one per channel.

[jk13]

He means the tweeter "crossovers" you are using are too low at 2750Hz, plus the 6db rolloff of just a capacitor is also pretty shallow allowing even lower frequencies in.

Those tweeters list a frequency response of 5k-22k. You are asking them to play half of that lower end frequency and with the shallow rolloff if you have your treble control up at all you could be playing them quite a bit lower. I would bet you are overheating them and in turn overheating the caps too, which is causing your issue. Build or buy the proper crossovers or a set of tweeters that come with their own crossovers and leave your controls flatter on the top end if you have them turned up at all. I am a big fan of subtractive eq'ing to avoid issues like this.

[Krazykid122]

He means the tweeter "crossovers" you are using are too low at 2750Hz, plus the 6db rolloff of just a capacitor is also pretty shallow allowing even lower frequencies in.

Those tweeters list a frequency response of 5k-22k. You are asking them to play half of that lower end frequency and with the shallow rolloff if you have your treble control up at all you could be playing them quite a bit lower. I would bet you are overheating them and in turn overheating the caps too, which is causing your issue. Build or buy the proper crossovers or a set of tweeters that come with their own crossovers and leave your controls flatter on the top end if you have them turned up at all. I am a big fan of subtractive eq'ing to avoid issues like this.

Alright thanks alot! I was thinking i might be overheating them, but i dont know much so i said thats probably not it lol. i do have the higher end boosted a bit ill set them to flat, i have mids/lows in the negatives, i could tell you exactly what freq if you wanted.

You think the same thing is happening to my door speakers that's why it starts to sound like that?

If i were to buy new crossovers instead of new tweeters at the moment, what db rolloff would i look for? im not sure what all that means, gonna have to look around on here and do some research.

-EDIT- Google is awesome, i understand the slope rolloff