# wake up in the morning to no BASS!!



## NJPCRX (Jul 25, 2012)

I posted this in the technical section, but nobody cares 

I have a kenwood DNX-9140 head unit. The sub output goes to a flush mount RCA bass knob, then back to the back of my vehicle where it is split with a Y-adaptor and then goes to 2 US Amps USA-400's running an oldschool stroker 18 (one amp per coil each amp 4ohm bridged) Did this install myself like all the others and everything was fine, since I did it last spring. Today I get in and set off to work and the bass is so low its hardly noticeable. Sounds just like I turned the bass knob almost the whole way off. Head-unit is playing, 4 channel amp is normal, sub amps are on and woofer is playing (but super low volume) First thing I thought was the bass knob maybe so I bypassed it. Same ****. Reset the head unit, same ****. Grabbed the multi meter. All powers and grounds are good, sub coils measure 4ohm. No funny noises sub will respond to volume changes just stays extremely low volume. Bass knob seems to have no effect on the bass the whole way up, or down. The only thing I can think is the head unit subwoofer output went bad? How do I troubleshoot this? Can I measure the voltage output on the RCA's coming from the head unit to see if its giving the amps the 4 or 5 volts its supposed to on the sub output? I don't wanna send the headunit for repair unless I am sure. I'm kinda unfamiliar with this deck because its complicated to use and I have not had time to get real familiar with it even though I've had it for like 5 or 6 months now. I would hate to have it be that the subwoofer output is off or something, lol...


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## SkizeR (Apr 19, 2011)

old school discussion isnt going to get any then either. and yes check the output voltage of the head unit


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## miniSQ (Aug 4, 2009)

This should be in the general section if you want the most people to see it.

Can you send the bass knob a different signal than than sub out? Since I am assuming the rest of the speakers are fine...what happens when you send the bass knob ( what brand and model is this BTW)...can you send it a signal from the front or rear outputs instead of the sub out? That would rule in our out if there was any trouble with the HU.


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## NJPCRX (Jul 25, 2012)

I bypassed the bass knob all together with female rca couplers and there was no difference. How do you check the output voltage of the RCA output??????? Stick the lead in set on VDC and put the other lead on ground with volume all the way up??


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## SkizeR (Apr 19, 2011)

positive lead to the inner, ground lead to the outer, set to ac volts


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## NJPCRX (Jul 25, 2012)

Ok, so I go out to check the voltage and it was working. I don't understand. I checked the voltage anyway, and the readings didn't make sense. On VAC with the volume up pretty high, I wasn't getting much more than a volt? I checked the 4 channel and it was the same. Explain further please how to check the voltage. Should you play a test tone like when you set gains? Are you sure its VAC and not DC?


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## ChrisB (Jul 3, 2008)

Some meters only measure AC voltage at 60 Hz, which happens to be the frequency of US household AC current. Repeat the RCA measurement test with a 60 Hz test tone. Make certain your RCAs aren't connected to the amplifier when you do so and also disable any crossovers.


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