Infinity Kappa distorting...puzzled

[amf83]

The Setup: I just bought a kappa 120.1SE (has a rating of 300w RMS) and a sony Xplod 760w amp which runs 380w RMS at 4 ohm to the sub. The kappa is in a 1.1cu. ft. box; all wiring is the right guage, good connections, etc. Polyfil liner in the box. Amp low pass filter is set at 90hz. Gain and boost are at factory default.

The Problem: The sub handles really low test frequencies great...plays them loud and clear; some songs and types of music play okay. I am interested in SQ not SPL. However, at moderate/low volume and higher, many songs/sounds cause the sub to distort with a buzz that comes from around the edge of the speaker. It's not any physical vibration in the car--it is coming from the driver. This can only be heard if you are in the back seat near the sub. From the front, everything sounds very good. I do not know if this buzzing, almost snapping sound is normal. It seems to occur more often at the higher end of the crossover frequency with bass that isnt real low. The 40hz range is fine.

Thoughts: It looks to me like the speaker is travelling too much-- it really gets moving even at low volume. This sounds like 'clipping' but the amp is matched well on power. Any ideas on what to do to fix the problem? Because I do not hear it with the trunk pass-through closed or when I am in front, it's not a sound issue, but this sound doesn't seem normal so I am thinking it might be damaging the sub, eventually. Help! This is my first install and I did my homework....

-adam

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[wesleysh 10+ year member]

I read a review on that Sony amp before. I thought it was on Car Sound but now I can't find it. Anyways, they had similar results when running subs with it. When they hooked the amp up to some component speakers it sounded great, so they concluded that the amp is just not good at running subs.

There really is no such thing as a "factory default" on your gains. You are supposed to adjust that yourself to match your headunit.

 

[abercrombie2582 10+ year member]

that sony amp has a tendency to shut off just to let you know. The infinity kappa is a great sub, but your sony amp is prolly clipping and eventually it will start blowing fuses. You should prolly look for another amp like the jbl 600.1 at ikesound.com , $205 shipped. I only say this cause my friends have had sony amps and they all blew. SOny just can't make good car audio. Hope this helps.

 

[amf83]

Thanks...I am going to try a friends amp just to make sure it isn't the sub or something else- then the sony is going back. Very disappointing i must say, especially since i am over my budget on this project already! Thanks for the info on the amp.

-Adam