[jin]

Is there any easy way to test if its the speakers or the L7 amp?

If it is the amp what are the cheapest options to fix? Can the amp be repaired?

[ctuna]

Repair resources
http://www.e90post.com/forums/showthread.php?t=635672
http://cgi.ebay.com/ebaymotors/BMW-C...ioQ5fVideo#ht_
http://www.diyparadise.net/bmw_cd73_repair.html
http://www.bimmerfest.com/forums/sho...d.php?t=761513

Repair
http://www.bmwradiorepair.com/?gclid...FccbQgodIEn0Cg
http://beckerautosound.com/
http://www.bmwgm5.com/Logic7_6941681.htm

[Rollo`]

I just replaced my under seat hifi subs. The driver side started distorting and once I began investigating I realized my passenger side wasn't working at all. I now believe I have just had one working sub for almost 2 years--which is especially aggravating since I could have gotten it replaced under warranty. (extra sub in the trunk made it less noticeable)

Anyway, the reason I said all that is to say that I would guess your problem is the sub and not the amp. There are a set of L7 subs on the classified right now for 150 and an L7 amp for 300. good luck!

[Soul_Glo]

The crude way of doing this would be to download an audio tools app to your smart phone and then place the mic near the speaker and see what frequencies (if any) you are hitting... some free tools are great for checking things like polarity too.

Personally, I would just take them out and test them on a bench. Once you have ruled out the speakers (probably easier) then you can diagnose the amp if need be. Before moving on to the amp, I would try some el cheapo replacement speakers (don't have to be subs or even the same size) as long as you can match the ohm and wattage.. that way you'd rule the speakers out for sure... and know that the amp was playing up.

[bmw325i]

Unplug the connector under the seat and use a multimeter to check the impedance of the speaker. It should be just under 4 ohms for the logic 7 underseats.

You can also test the other end of the connector to see if power is going to the speaker. Just set your multimeter to ac volts and play a test tone.

[csu87]

Originally Posted by bmw325i

Unplug the connector under the seat and use a multimeter to check the impedance of the speaker. It should be just under 4 ohms for the logic 7 underseats.

You can also test the other end of the connector to see if power is going to the speaker. Just set your multimeter to ac volts and play a test tone.

+1. Only good way to tell where the issue is.