New amp needed?

how high of a bass note do you mean? if the amp can produce the power for the low note then it has plenty for a higher less demanding note.

maybe your crossover is set too low for it to play the upper bass freqs you want.

my sub is set to 80HZ and will taper out around 90ishHZ to blend in with my mids/ mid bass well. those are set to 80HZ as well.

getting some good mid bass up front can help too.

 

is the box ported? and if so whats it tuned to?

 

ok i think i know what the weird noise could be.

a low pass crossover will only let the frequency you select pass thru, and taper off the freq a few db's past that.

mine is set to 80HZ (hertz) or cycles per second. 30HZ tone will move a sub 30 times per second. 80HZ will move it faster. still following,lol. it can get very confusing i know.

at 80HZ the crossover lets it play without any attenuation. now lets say i have a 100hz tone my crossover will have attenuated it by 18db's. (db= decibel) if youve seen a crossover. it will say something like" 12db per octave". meaning it will slowly lower the output to that speaker gradually so its not playing as loud and will blend in with your other speakers. the higher the slope"db per oct" the faster it tapers off the sound to that speaker.

crossovers have 6,12,18 and 24 db per oct. settings. some can go higher, but those get very pricey.

just so you know lowering the output of a speaker by 3db's is lowering the output by half. so a 12 db per oct filter(crossover) should lower the output from that speaker by 4 times. below or above the cutoff point.

for a midrange its the same. only it will limit how low of a freq a mid can play. for a sub it limits how high it will play.

my mids are set to 100HZ hi pass. so anything under 100hz gets filtered the same way..... gradually. so a 60hz toned from then is almost inaudible.

ok so your high note sounds like something is broken.... is it a loud buzzing sound? if so then the box could be coming apart and you just dont know it. or something is buzzing at those higher notes. its like if you blow thru a sheet of paper to make it whistle. it will make a noise the faster it vibrates. so your box panels could be vibrating off each other at the high notes.

i had an amp or 2 screwed into my box before but kept hearing a muffled buzzing on higher notes. turned out to be one of my amps(real old amp) outer cover.

do this... play some high note tones and physically hold the box. if it stops rattling.... even a little you have found the source of your noise.

you can fix it if you want by screwing it where its loose. i had an old beat up bandpass box do the same thing. it was falling apart. screwing it helped for a lil bit. now the box is sitting in a closet.

http://www.bcae1.com/
this site is very informative when it comes to car audio. its is quite the read, but well worth it. ive only scratched the surface of all the confusing stuff,lol.

i hope i helped a little.

 

High pass suggestions

Sounds like your subbass is in pretty good shape.

But for the rest of the system, I really like to use 6-channels amps for front and or rear.
This way you can put 2 channels on the rear (just mids to save $$), no components required really,
and bi-amp the front stage, esp if you can run 2 ch to the tw/mids, and your install can accomodate
dedicated midbass (active bandpasss 60 - 250 Hz) for the doors. This way your mids are not forced
to be midbass drivers as well, and of course you can tune the midbass your tastes.

Passive 3-ways are no where near as good, since you are stuck as far
as tuning anything but the tweeters output level. This kind of architecture
yields a ton of sonic advantages, for obvious reasons.

Just my .02 cents.

Rick