Cirdecus Posted June 20, 2017 Share Posted June 20, 2017 Hey guys, I just plugged in an RSW-12 sub I purchased from someone along with a pair of R7 Towers and the RC7 Center. It worked great at first, then I noticed that the tower woofers weren't working hard at all and all of the bass was being sent to the sub, which created this compartmentalized bass sound. I decided to dig into the receiver and maybe set the front and centers to "large" and then adjust the crossover to something like 50hz. However, when I did this, the sub was almost silent. After adjusting a few different ways with combinations of large and small along with different frequencies, the sub now just constantly lets out a loud noise all the time. The noise is max volume even at the lowest setting and persists even when the source is disconnected. Any ideas on what is going on here? I have the sub cross over knob at around 70 now, Auto On enabled, and LFE disabled. I'm using a Pioneer Elite VSX-53 amp Quote Link to comment Share on other sites More sharing options...
Cirdecus Posted June 20, 2017 Author Share Posted June 20, 2017 It appears this is tied to the RCA cables. I've replaced them, but it didn't change the issue. When the cable is disconnected from either the subwoofer or the receiver, the ridiculously loud, house-shaking bass goes away. But if either are connected, it comes back, even when the receiver is powered off and unplugged. I noticed that unplugging the HDMI cable that runs between the TV and my receiver cuts the noise in half. Maybe this is a grounding issue? Or some kind of ground loop? I've heard of ground loops causing "hums", but this isn't a hum, this is the sub releasing max volume bass. Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted June 20, 2017 Share Posted June 20, 2017 Ground problems are a hum. Quote Link to comment Share on other sites More sharing options...
jason str Posted June 20, 2017 Share Posted June 20, 2017 Throw a 2 prong cheater plug on the subwoofer power cable and see if the noise goes away. Quote Link to comment Share on other sites More sharing options...
Cirdecus Posted June 20, 2017 Author Share Posted June 20, 2017 56 minutes ago, jason str said: Throw a 2 prong cheater plug on the subwoofer power cable and see if the noise goes away. I can do that. Strangely enough, neither the receiver nor the sub have a ground prong. Quote Link to comment Share on other sites More sharing options...
jason str Posted June 20, 2017 Share Posted June 20, 2017 15 minutes ago, Cirdecus said: I can do that. Strangely enough, neither the receiver nor the sub have a ground prong. Won't help then. Do you have another receiver to test with ? You can also unplug everything from the current receiver and see if the noise goes away then hook things back up one by one to determine if another component is causing the problem. Quote Link to comment Share on other sites More sharing options...
Cirdecus Posted June 20, 2017 Author Share Posted June 20, 2017 No, i was thinking of just finding a mono audio out on the TV to test with. Maybe it's the receiver, who knows. Quote Link to comment Share on other sites More sharing options...
Cirdecus Posted June 20, 2017 Author Share Posted June 20, 2017 Could there be an issue with the sub? Quote Link to comment Share on other sites More sharing options...
jason str Posted June 20, 2017 Share Posted June 20, 2017 1 hour ago, Cirdecus said: Could there be an issue with the sub? Could be, best to make sure before blaming the amplifier. Quote Link to comment Share on other sites More sharing options...
Cirdecus Posted June 20, 2017 Author Share Posted June 20, 2017 29 minutes ago, jason str said: Could be, best to make sure before blaming the amplifier. How can I? Quote Link to comment Share on other sites More sharing options...
jason str Posted June 20, 2017 Share Posted June 20, 2017 6 minutes ago, Cirdecus said: How can I? See my second post on your thread. Quote Link to comment Share on other sites More sharing options...
babadono Posted June 20, 2017 Share Posted June 20, 2017 @Cirdecus You need to test the RSW-12 first by shorting the RCA input jacks with dummy plugs. There will be no input signal so you will need to set the Auto/OFF/ON to ON. If the noise/hum persists with the inputs shorted the problem is in the sub itself. Try this test first and come back to us with the results. A dummy plug is simply an input connector with the center pin and shield connection shorted together. Quote Link to comment Share on other sites More sharing options...
Cirdecus Posted June 20, 2017 Author Share Posted June 20, 2017 2 hours ago, babadono said: @Cirdecus You need to test the RSW-12 first by shorting the RCA input jacks with dummy plugs. There will be no input signal so you will need to set the Auto/OFF/ON to ON. If the noise/hum persists with the inputs shorted the problem is in the sub itself. Try this test first and come back to us with the results. A dummy plug is simply an input connector with the center pin and shield connection shorted together. You are awesome, thank you. So just to clarify, I would use perhaps an RCA cable that has the outer ring and center PIN connect together on one end and the other end plugged into the sub? Quote Link to comment Share on other sites More sharing options...
babadono Posted June 20, 2017 Share Posted June 20, 2017 @Cirdecus yes that should work for the test. Quote Link to comment Share on other sites More sharing options...
Cirdecus Posted June 21, 2017 Author Share Posted June 21, 2017 Alright, I pulled the cable from the back of the receiver and shorted it by touching a flat head to the center and the outer ring and the max volume bass turns on when shorted and off when normal. The sub is still plugged into the same power as everything else. What can I try next? Quote Link to comment Share on other sites More sharing options...
Luv_sum_Horns Posted June 22, 2017 Share Posted June 22, 2017 5 hours ago, Cirdecus said: The sub is still plugged into the same power as everything else. I have some low end contractor grade Velodyne subs that absolutely hate having their AC power cables anywhere close to any other power cables and get angry just as you describe. Try plugging the sub in somewhere else and make sure the cable is isolated from other power cables. Quote Link to comment Share on other sites More sharing options...
Cirdecus Posted June 22, 2017 Author Share Posted June 22, 2017 Good idea, let me try that Quote Link to comment Share on other sites More sharing options...
Cirdecus Posted June 23, 2017 Author Share Posted June 23, 2017 Ok guys, I grabbed that huge sub, hauled it upstairs and tried the "short" test and it appeared to only let out a "hum" which would increase in volume as you raised the volume of the sub, but the loud, insane max bass belching was gone. However, when i brought it downstairs, it behaved the same way. The only difference is that I used a flathead screwdriver in my previous tests to connect the middle pin to the outer ring and I used my keys to do it this time. So many i goofed the test. In any case, I plugged it back into the receiver and got the same massive bass sound upon turning it on. Also, it doesn't matter whether the red or white RCA of the splitter is plugged into the sub, both of them alone will produce the same results. I'm thinking it may be the sub or it may be some insane grounding problem with my house and maybe some kind of in-line device will take care of it. No idea. I'm still waiting on my second RSW-12 amp to be repaired so i can try a different sub woofer. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted June 23, 2017 Share Posted June 23, 2017 With absolutely nothing plugged into the sub other than the power cord (no RCA whatsoever) does the sub make noise? Quote Link to comment Share on other sites More sharing options...
babadono Posted June 23, 2017 Share Posted June 23, 2017 19 hours ago, Cirdecus said: I'm thinking it may be the sub or it may be some insane grounding problem with my house and maybe some kind of in-line device will take care of it. No idea. Didn't you say both the sub and receiver have 2 prong cords? Let's not get off on a tangent. Can you make a dummy plug? I answered that your shorted cable should work but i did not realize you meant shorting it with a key temporarily. I do not like adding more variables into equations. I am looking at the schematic of this and there should very little difference between open inputs like CECAA850 above has asked about and shorted inputs like I want you to try. The easiest is open inputs of course. The shorted inputs more closely simulate how it will be hooked up to your receiver. Either way we need to know with no signal what is the behavior. And don't forget with either open or shorted inputs there is no signal so be sure the AUTO/OFF/ON is set to ON @Cirdecus Quote Link to comment Share on other sites More sharing options...
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