kicker comp 15's fluttering during low bass notes

[helotaxi 5,000+ posts]

Right now your subs are sitting in an enclosure that gives them a Qtc value of .92. That is a decently damped alignment but not too extreme. It's way too high for my tastes.

That .92 anechoic Q will probably be right around .7 in car. Can't forget that the car is part of the enclosure, too.

 

[Immacomputer 10+ year member]

That .92 anechoic Q will probably be right around .7 in car. Can't forget that the car is part of the enclosure, too.

That's true, but it will still give a peaky sound with a struggling low end. Could it be the cause of his issues? It could be. It also might be something else. It might just be the drivers.

 

[helotaxi 5,000+ posts]

A .7 Q is just that. Its a pretty flat response. The cabin gain of the car will fill in the low end assuming that the subs are properly producing the freqs. Every system, even sealed, that I've ever had leaves the subs "fluttering" at low freqs and the output drops off. It typically happens at freqs and power levels where the motor just flat runs out of poop to overcome the force of the suspension and the enclosure. You can reach Xmax without reaching Xsus or Xmech and never bottom out the sub. The result is the same, the sub runs out of steam to reproduce super low freqs at a similar level to the higher freqs and the cabin gain can only do so much. This will happen sooner in smaller boxes FWIW.

 

[liftedcj7on44s 10+ year member]

Thanks for all your replies guys. I went and got a few bass CD's yesterday to try and help set the amp up right. i have tried various test tones and have come to the conclusion that the subs just cant handle it. They are great for playing in the 50hz on up range but anything around the 30-40 range just makes them sound like crap. My single IDQ12 i had played the lower notes 10 times better. I just think that the subs cant keep up or something. I can lower the gain on the amp and get the flutter out but then there is no volume to the subs. I went yesterday to hear a 12w7 and was not impressed at all. i mean it did sound great but for 749 dollars its not all that. It was even in the ported HO box and man that box is way too big. I am making a new post as i have some questions about what i am going to get and some issues i may face. Thanks guys for the help. Helotaxi your suggestion is spot on and this is what i think is happening.