Originally Posted by Ice_Man

Two Nightwish CDs on the way from Amazon and no bass...

Originally Posted by Ice_Man

So... yesterday I was transitioning from Evanescence to Michael Jackson, and as the first notes of Bad begin emenating from my system, I realize I have no bass. Seconds into the song, I hear a moderate thump followed by more silence from my trunk.

I know my amp has power and that all fuses involved are still good. I need to test the:

- Preouts on my head unit (Pioneer 7600)

Play a continous sine wave over and over at say... 80hz or lower through your CD player with your back speakers disconnected and the head unit faded all the way to the back (no point in playing it thru your speakers). You need to make a short RCA cable with a single male end and make it so the other end has the wires stripped and can be hooked up to a Digital Multimeter (DMM). Set the range on the DMM to the 200v AC and connect the RCA contraption to the outputs. With the volume up and the sine wave playing you will get a reading on the DMM. You really only need to test the preouts that are giving you trouble and you can only check one channel at a time. If you are using both channels on a pair of preouts, you need to check them both individually.

- Pre-out cables

Get a barrel jack (female/female RCA adaptor), plug both the RCA contraption and the RCA cable into it and test for signal again, using the same process that I described above. Make sure the RCA cable is plugged into the head unit you will need signal going through it to test. Note if there is a SIGNIFICANT voltage drop.

- Input stage on the amp

Hook a working speaker up and test at low volume. If sound comes out the input stage is working. Or if it doesn't work, try either A) checking the amp's RCA outputs assuming it has them which I imagine it would or B) open the amp and check the PCB

- Output stage on the amp

Hook a known working speaker up and put volume to it.

- The sub itself

Remove from the box and check for damage. First thing to check is the tinsel leads which are the silver wires going from the terminals to the voice coil. If it is bad you will know because it will be physically broken, probably at the terminal. Next, smell the sub very closely all over. If you know what burnt voice coils or electronics smell like you will be able to identify it fairly easily. Next, push down even and ever so slightly on the cone. Try to identify if the sub does not want to move up and down or if you get bad noises when you move it. Check for other physical damage. Get a DMM that can check for continuity and hook it up to the + and - speaker leads. If you press down and it has no continuity the subs is toast the voice coils are bad.

That's about all I am physically capable of thinking of so good luck.

poiuytrewq

I get no sound/noise/anything from the subwoofer which makes me wonder if it is blown or if it is just getting no signal. What is the best way to test a pre-out level signal? This wasn't even a super-hot Arizona day, just moderately high temperatures, so I'm hesitant to say anything overheated unless a short was involved.

Two Nightwish CDs on the way from Amazon and no bass...

Originally Posted by MegaHurtz

Try plugging the sub into the wall and take a video if it does anything

Originally Posted by J187

You know mega has done some of his finest work when he closes with

poiuytrewq. Which BTW, I can't beleive you've replicated the same word from before. HA, at least you'll find the post again