My celestion s20 subwoofer won't play if i hook it up to sub out on receiver.but will play if i run a regular speaker wire to it. I know sub out is working on receiver.

You don't mention what receiver we're dealing with so we have no idea what facilities it has that might take advantage of the Line Level inputs on the sub's amp.

You probably COULD just run the Speaker A wires from the receiver to the High Level inputs on the sub, then run another set of speaker wires out to your regular front Left and Right speakers. This sub is self-amplified so it would use the speaker level from your receiver only to guide its internal amp.

If you have volume-controlled pre-outs on the receiver that could be used, too.

I can't find a manual for your sub but go here, register for free and download the manual for a typical powered sub. They all do it pretty much the same.

http://www.retrevo.com/support/Boston-Acoustics-PV500-Subwoofers-manual/id/522dj486/t/2/

as long as there is a speaker out from the receiver you should be ok just make sure polarity for spkr is right --remember you workng with AC current bad wire will cause fire==

unplug it when your not in use,,,

Back in the old days, subwoofers were powered by the voltage from your receiver, through speaker wire.
Nowadays, subwoofers have their own power, hence not having speaker wire connections anymore.
It's unlikely that you'll be able to connect your old subwoofer to your new receiver.
You'd need to get a new one, which if you don't mind buying closeout, can be found on eBay pretty cheap.

Greg- Powered subs are better than non-powered subs (also known as passive subs), anyway I see the TX-8511 has no sub pre-out on the back panel, so you need to decide what sub you will use and run from the receivers left and right speakers output into a subwoofers speaker in from speakers then back out to speakers, look at the back of a subwoofer and you will see like 4 sets of speaker hookups 2 in and 2 out, what this does is takes the low end or bass and drops the signal to the subwoofer then takes the mids and highs out to your left and right speakers, unless your regular left and right stereo speakers have large woofers a sub is the way to go.

Instead of connecting it to the sub output, try it on the L or R output of your amp.
This will eliminate the Denon.
If this fails, you need to test the loudspeaker driver unit whilst disconnected from the sub amp. Use a 1.5v cell (AA or bigger) connect using croc leads to the speaker's terminals. If the speaker is OK, you should hear a click. If you hear nothing, the speaker unit is faulty.

In general, there are two ways to hook up your sub-woofer. First using the high level outputs from your receiver ( speaker output from the front R & L speaker terminals ) run a set of wires from the outputs to the speaker inputs on the sub-woofer, you do this in concert with the speaker wires going to the front R & L speakers which you then attach to the R & L speaker outputs on the sub woofer amp. Note that the sub woofer doesn't power your front speakers, the connections from the sub amp are just a pass through connection where the signal needed by the sub is parasitically taken from the inputs.
Second is via a low level output from your receiver / amp to the low level input on your sub amp. This is normally done via a RCA type of patch cable and connected to the sub woofer RCA jack on the rear of the source receiver or amp, Next run the patch cord to the sub amp an into the RCA jack input. IF you have a right and left input, use the Right input.

john

I added the subwoofer wires to the right and left front speakers.

cheak setting in sterio out put for sub on ect does woofer have sperk wire going in and out use them then ok