Subwoofer not working

if you have your front and centers set to 'small' you want your Bass out to be subwoofer only, and the rca jack labeled 'sub out' is the only place to connect your sub to if you want to control the frequencies with your reciever. I dont know the brand of your sub, or the inputs on the back of it to advise you where to connect, but it sounds like it worked for you at one time, but suddenly it does not

Hissing? How loud? A sub isn't even capable of making high frequency sounds at normal volumes.

The Pioneer manual would tell you how to enable and test the subwoofer output.
Page 17 and the MACCV procedures on Page 33 (auto) or 43 (manual)

Sounds like this is a powered subwoofer (as it has a line input). If this is the case, the 'sub W' output of the receiver will NOT work, as it is only sending speaker level to the line input.

You will likely go from sub W directly into the speaker input on the sub. The output is probably used for looping an additional sub into the system.

Any powered sub-woofer will work with it. Check the back of the Technics, make sure there is an RCA output labeled "Sub-woofer" or "Woofer" or "Sub". If so, you can get any brand of powered sub woofer and it will work. A powered sub-woofer is one with an amplifier for the sub built into the box and you will need to plug it into an A/C outlet as well. The only exceptions to what will work with this unit is to make sure you are not buying a sub-woofer that is made to only work with the companion unit it is originally sold with. Many Panasonic and JVC sub woofers are like this. Just look for a sub-woofer that is not part of any system. Velodyne makes some really great sub-woofers that would work nice with yours, but they can be a little expensive, but they are very good.

If your Technics has no RCA output for the sub-woofer, you will need to make sure that whatever powered sub-woofer you buy has a speaker level input for it. Most powered sub-woofers have this feature, so that you may just run the front speaker outputs of the receiver into the subwoofer and then the sub-woofer will have a set of speaker outputs right below the speaker inputs so you can still have your front speakers connected to that and not loose anything from your system.

I hope I have explained this in a manner you will understand easy, if not just post whatever questions you may have right on this thread and I will get back to you as soon as possible.

It would also be appreciated if you could rate this solution if you no longer need any help from me. If you do require more help, please wait to rate this until we are finished. That way I do not get an undeserved bad rating when we have not even finished our communications.
By the way, A "Thanks for trying" and "Helpful" rating are really not good, they always end up lowering my overall score.

Dave

THIS UNIT HAS NO SUB WOOFER AMP IN IT. THE ONLY WAY TO OVER COME THIS IS TO HOOK THE LEFT AND RIGHT FRONT SPEAKERS STRAIGHT TO THE SUB WOOFER AND THEN GO FROM THE SUB WOOFER BACK TO THE INPUTS ON THE BACK OF THE UNIT FOR THE FRONT SPEAKERS. THE SUB WOOFER THIS WAY WILL EXTRACT THE BASS AND THE FRONT WILL RECEIVE THEIR PART. THIS SOUNDS CRAZY AS HELL I KNOW BUT THAT'S HOW I GOT MINE TO WORK. THE OUTPUT FOR THE SUBWOOFER IS USELESS AND PUT THERE FOR YOU TO HOOK UP AN AMP FOR A SUB WOOFER. EVERYTHING HAS SHORT COMINGS, AND THAT'S THE ONE FOR THE AX-720.

Think as an expert... Probably from my experience repairing woofers etc... the cone (1) or the spider (2) isn't well glued onto the woofer skeleton(or both???) The woofer cone must be absolutely centered or else you will get those clicks in low frequencies(you also get them in higher frequencies but you can't hear them!) I must say that it is very difficult to repair a woofer by your own. I suggest to return it back where you bought it and take another one (i suppose that you have a guarantee ha?).

take it back for refund or exchange without delay. Too many times, there are cases of faulty factory assembly. Most likely a poorly connected wire inside sub, which fell off after a few booms.

If I am not mistaking here, you need a self powered subwoofer to use with this unit. Those are line driven outputs for this unit. Make sure there is a wall plug on the sub that is plugged in. Good Luck

This receiver can only take a self powered subwoofer I'm afraid. You could get a power amp and power the sub like that but in the long run I really think you would be happyer to get a new subwoofer. Good Luck