Signal Not detected....

feelx77

Hi guys,

I set my parents up with a PSW12 Sub-woofer few years ago when we purchased two RTi10's. Sub-woofer is in great shape and plays just fine.

Only consistent problem which has been on-going is that the sub-woofer will not auto turn on or in other words it does not automatically sense the incoming audio sub signal and start playing.

The power is always fine, the led is always lit red and turns green when playing like its suppose to. I have never heard any power struggle issues when it is on playing even loudly. Very good clean sound.

The weird thing is this: I can literally unplug the RCA plug from the back of the sub and just plug it right back in. Than it always senses the signal and immediately turns on playing. I had the power switch set to auto for the longest time. So I thought well I will just leave the switch in the always on position if I have to. Still made no difference. I could put it on anything with some bass & crank the amp a little bit and only the mains play. As always just simply unplug then plug back in the RCA on the back of sub and all is perfectly fine again.

Its been bugging me for a long long time cause it works just fine. So I have been wondering if I should just pull the amp board and send it to Polk or what?

The RCA cable fits snugly always works when re-plugged in and its in perfect new condition. So new cable for giggles, send board in to Polk?

Only thing I have not tried for a while is to plug the RCA from the main sub input instead into the Left channel RCA input on the back of the sub-woofer and see it the issue still continues there as well.

Also, just for fun I did increase the output by 1db from the receiver for the sub-woofer out signal. Made no difference.

feelx77

Final note: When the sub was new the amp board was faulty and back than the speaker would phase slowly in & out of sound and was distorted. Polk did replace or service the board way back than probably around late 2006 guessing under warranty.

disneyjoe7

If audio is being played on a low side, the sub may not see a good signal to turn on. I have this issue when I'm watching tv at night when someone is sleeping. When you replug the RCA signal the sub sees a great audio input because its missing the ground, at this time it turns on. I'm sure later the sub would turn off, since it may not see a nice input.



Steve

feelx77

Yeah that makes sense and I hear what your saying. Even my PSW1000 at home turns off if I have the volume pretty low for news before bed.

But i'm talking turning the volume up on the receiver from an already audible state/sometimes low admittedly cause dad can hears flees coughing. Its just I can put it on a rap music channel on comcast, crank it up and RTi10's crisp, clear, loud but nada from the sub. Go unplug RCA and plug back in than instant full powerful clean bass. Baffles me every time.

feelx77

Just tried it right now. Dad was watching a movie out there. Put it out dance music, increased volume to about-12db on receiver. Nothing from subwoofer. Red light on back. Went and unplugged the RCA, plugged in, turned immediately green and started pumping nicely.

Thinking at least go to Wal-Mart and buy another Phillips Digital/Sub RCA cable just to rule it out and if it still acts up, than guess have no choice but to send in to Polk. Receiver is a Marantz SR6400 and sub output is at +1db out. Going to wait a day or so and see what you guys think. Appreciate all the input. Just ready to fix for them and move on.

feelx77

Just FYI, checked the RCA cable I'm using its meant for SPDIF or Digital Audio hookups. Could that maybe be the problem. I mean its still an RCA and the signal going to the Sub is digital I thought? I could put a labeled as "sub use" RCA cable on it. Maybe different impedance or OHM capabilities in the cable possible?

disneyjoe7

The signal to the sub should be analog not digital. Do you have a sub output, the sub woofer should be connected to this output.

disneyjoe7

BTW Welcome the Polk Audio Forums.

feelx77

Thanks, browsed for years and have quite a few Polk speakers. Glad to be here and always supported Polk products over the years even for automotive.

Own Myself: 4 RTi10's, 1 PSW1000, 1 CSi5 (5.1 setup)

Parents Own: 2 RTi10's & 1 PSW12 (2.1 setup)

feelx77

Oh yeah, just so you know I'm a techie so not usually too dumb on audio hook-ups and hi-fi gear. Hell I can strip a laptop and put it back in perfect working order using my memory alone and installed many a car systems during my youth.

Having said that the RCA is hooked up to the Marantz receivers dedicated sub-woofer RCA out jack directly into the LFE input on the sub as we speak. And its working now still flawlessly since I unplugged plugged back in few minutes ago from my earlier post. The cable is labeled Digital Audio. I think I'm using the same kind of cable at my house. Going to check later and if its different than I'm going to buy another cable for test purposes just to rule it out.

disneyjoe7

I don't think your cable is a problem, so if it works I sure you're ok.

And don't worry stick around you will learn stuff everyday.

feelx77

I'm using a better different cable at my house. For testing I hooked up a cheapo RCA laying around at parents house in place of existing cable. Told dad to monitor it (the green led) and sound. So far last night it seemed ok.

If it keeps working; than will buy a replacement cable for him.

And oh yeah, thought about and yes the signal going to the sub is analog. Had to remind myself their is no decoding or need for decoding at the subwoofer. So a digital cable is not needed.

My logic only was when I used the cable back when I set up his system was that if the cable was good enough to carry a SPDIF digital signal than surely it was good enough to work for a simple analog sub out connection.

Will check it again tonight and see if still working fine with cheapo RCA cable....

disneyjoe7

Some better cables are build with a RG cable RG59 or RG6 which is used for cable tv wiring. These wires are 75ohm also which work with digital output also, so knowing this I'm sure your digital is fine.

feelx77

Well, its been working perfect now with the cheapo RCA cable. So guess the cable was either off in signaling OHM/impedance etc or just plain defective. So ordered two extra dedicated sub-woofer RCA cables. They will be here in a day or so.

Just wanted to share that something as simple as a crappy or defective cable could be the problem as it seems to be for my issue. Has been turning on and off perfectly now.

Should have swapped cables a year ago. Just did not think it would be that simple. Oh well, happy now = )

disneyjoe7

I'm glad I could to help you out.

feelx77

Looks like it was just a bad RCA cable. Received the new subwoofer cable and its been perfectly fine ever since for well over a week now. Just wanted to share because everyone should know that even something as minor as a cable that "looks" ok may not always be ok.


Lesson learned: Look for the small minor stuff first before jumping to big conclusions.