How To Test Your Home Theater Subwoofer

[@neorock6135]

I have an issue with a home sub, got it brand new in an open box from someone. And just like you mention at 2:05 if I push down on the cone, my readings go to zero. However, pushing down on it, it doesnt sound bad, no raspy sound. And when I connect a battery to the terminals, it does move. So then I tried the same pushing down test on a small speaker I have. It works perfectly, but the readings for it also went to zero once pushed down. So how can I tell if the bad one has a short? or if its an issue with the amp? Thank you.

[@richardvedvik979]

Man, sorry that I missed your message. Since it's been 6 months, I assume you found a solution. When testing a sub, it needs to be disconnected from the receiver, and from any other speakers/subwoofers. I test with the sub disconnected entirely since a multi-meter will measure everything connected. When pushing down on the sub you will see DC Resistance change, but you only take note when the sub is stationary, not moving, since the multi-meter can't measure AC Impedance but DC Resistance.

[@funkbro2]

I get proper resistance reading on my subwoofer, but it’s scratchy when doing 9v battery test. How do I ensure the woofer is good ?

[@richardvedvik979]

When making the connection to the battery, it will be "scratchy" when you make or break the connection. This test is just to ensure the windings are complete. The best way to test coil rub is a very low frequency signal played at low volumes to allow the woofer to "sweep". For me, it's usually a 5-10Hz sine wave at very low amplitude to watch the woofer throughout it's movement range.

[@funkbro2]

@@richardvedvik979 I’m going to borrow a friends amp and verify the driver before going and replacing amp components

[@brianleach1392]

How can we test the capacitors and the mosfets?

[@rgruenhaus]

I have an Onkyo TX-NR757 receiver and a Sony 8" subwoofer and I connect the one sub coax from the receiver to the subwoofer and I get no sound. The power light on the subwoofer is on!

[@richardvedvik979]

most receivers require you to turn the subwoofer output on in the menu. Ensure that you are using the subwoofer output on the receiver and the left channel input on the subwoofer itself. www.onkyo.com/manual/txnr757/adv/en/003.html

[@rgruenhaus]

@@richardvedvik979 I know I have the wires and settings on the receiver right, but I don't use subwoofers often and I am using a single coax to go from the Sub out on the receiver and am not sure about a powered subwoofer inputs!