I have a Kenwood KAC-9105D amp running two 10’’ Rockford Fosgate P3D410 subs at a 1 ohm load. My problem is that when the bass hits hard the amp will play some of the notes loud while other notes have around 1/4 the volume. I had the subs wired to a 4 ohm load which is 500 watts rather than >900 watts, and the sound never decreased. It seems to me that i’m not supplying sufficient power to the amp. I can install any parts i need, but i’m unsure of what parts ill need to upgrade or where to get them.. So if anyone can lead me in the right direction it would be greatly appreciated!
I'd suggest double-checking the body/frame ground for the amp and the sub wiring to make sure you have it correctly wired to 1ohm. You could also check the voltage at the amp with a DMM while it's playing to see how many volts the amp is getting; but, be careful you don't short it.
so at lower power the bass vol never decreased at certain frequencies, only on higher power? at first i was going to say its a box issue, but i doesn't sound like one after reading on. maybe they are getting too much power now and are distorting to the point where they won't go any louder. e.g.. clipping.
The box is to spec. The gain is at .5 and bass boost is at 8. Basicly every song will start out bumping hard, but around 45 seconds you can hear the bass get lower, but still hits the notes as if the subs were on a smaller amp. When they hit good, you can tell its a high powered amp, when they don't it just sounds like they are on a a 300 watt amp. When i had them at 4ohms the sound was still louder then what happens now. I'll have to wait till saturday to get my hands on a DMM, but i'll go try some new grounds in a bit.' Thanks for the quick replies.
I suppose it possibly could be a problem with your amp itself, but I'm really leaning toward more of a voltage drop or incorrectly wired subs. Is the amp going into protect at all?
Protection isnt coming on. Where do i touch the DMM to check for the right voltage? and should it be closer to 12 or 14 volts?
I'd first check at your amp. Connect the DMM leads to the + and - terminals and play your system and watch the readout. It should be around 12.5 with the car off and between 13 & 14 or so with the car running.
make sure it is wired correctly at 1 ohm. when wire out of phase, the subs will be louder on high notes, but when it is supposed to drop, it will be like nothing. make sure all the positives and negatives are wired together correctly.
its at 12.6 with car off. The max while its hitting hard is 14.2 volts, but after running for a few minutes it drops to 13.1 and then spikes down to 11 then up and continues to do this. Im guessing its not getting sufficient power? And i checked the wires, everythings right.
Yep, sounds like your charging system isn't adequately keeping your battery charged. Check the voltage at your battery with the system playing, too. Are you running a stock alternator & battery?
Yes, everythings stock, i'll check the batteries voltage tomorrow. Would changing the alternator be a big project? Also where would i buy one that puts out more current that i know will fit my car? And what do you recommend for batteries What about the big three? Should i try that first?
Definitely try the Big 3 first. Next I would upgrade the battery if that doesn't work, to a Kinetic, Optima, or similar. Any idea how many amps your stock alt puts out?
I believe it's 90amps. Is there anywhere i could buy new battery terminals and 0 gauge wire terminals ( i know where to get them online, but im anxious and dont want to wait). I already have a 15 foot spool of 0 gauge wire.
Are you running any signal processors? seen many issues with them over the years. voltage could be an issue also. But most amps nowadays will run rated power acroos the bandwidth at lower voltages due to heavily regulated power supplies.
Your problem is that amplifier isn't designed to run 1-Ohm loads. It is most likely reducing it's power greatly to prevent its catching on fire. You're lucky it hasn't. The sound never decreased at 4 Ohms because you had it wired correctly. Didn't that set off a bell? I can't believe nobody pointed this out.
According to the Kenwood site, the KAC-9105D Class D is 1ohm stable. Under General Features: "1-ohm stable (output regulated to 900 Watts)" http://www.kenwoodusa.com/Car_Entertainment/Amplifiers/KAC-9105D
I've seen other specifications that differ and knowing Kenwood's history, few of their amps were ever even 2-Ohm stable so I doubt they are 1-Ohm stable. That disclaimer "output regulated to 900 Watts" should raise a red flag, since every amp will attempt to produce twice the power when the load impedance is cut in half.
