Subwoofer woes

[Shintsu]

Okay, I finally rearranged things how I wanted and positioned my equipment the way I want but now the subwoofer is causing me a great deal of stress. Firstly, no matter what I do when I turn it on it thumps, when I turn it off it REALLY thumps. It sounds so god awful and scares me that it's just going to POP and then be dead. The subwoofer is only a polarized two pronger, not a grounded sub if that is of any relevance. It also thumps every time I turn my overhead fan on (including to adjust the speed).

Second, subwoofer hum!!! I've tried the old trick of undoing my coax cable to my TV to see if that mattered but it made no difference. The constant sound is driving me insane and is very annoying!

So, what can I do to solve both of these problems? The thump scares me the most, however the hum makes listening near impossible as it's a very noticable presence in anything I'm listening to. Someone told me that if I bought a power strip with EMI/RFI filtering this would eliminate the hum, however I have a fairly modern Cyber Power power strip that I thought had this but I couldn't say with certainty. Somewhere else I read that this kind of cable will make the hum stop:

What do I need to do to make both of these things stop? Both are driving me crazy!!

Ah, I think I found the model of the power strip I'm using. Looks exactly like this:

Apparently I do have an EMI/RFI filter on it...it's also 1250 joules rated if that matters at all.

 

[croseiv]

So, have you tried disconnecting the RCA cable from your sub (with the power off!!!)? Do you still get this "thump" at power on/off?

 

[Shintsu]

So, have you tried disconnecting the RCA cable from your sub (with the power off!!!)? Do you still get this "thump" at power on/off?

No, when the cable is not plugged in there is no violent thump. So this leads me to believe I do need that funky cable...

 

[croseiv]

Two other possiblites are that you have seriously amplified the signal going to your sub. For example, your preamp is boosted (nearly maxed), or your sub's gain/volume is maxed out. Is this the case here?

 

[Shintsu]

Two other possiblites are that you have seriously amplified the signal going to your sub. For example, your preamp is boosted (nearly maxed), or your sub's gain/volume is maxed out. Is this the case here?

I know what you mean. My preamp has a switch for the sub for either Flat, 60 hz or 120 hz but it is set at flat. The sub's level knob is set at about 5 and it goes from 0-10. No particular reason it should be doing it due to being turned up too loud.

 

[Shintsu]

I don't see how this could be such a great cause of subwoofer hum, but I am using some Monster cable (Didn't pay much for it, got the whole pack for $5 or I wouldn't have bought it) that came in the standard THX S-Video kit which seems decently thick and all to connect my subwoofer. I've been looking at BJC subwoofer cables and considered 8' of the LC-1 or 8' of the LV-77S (Unsure which would be better though), however that will not affect the violent thump when turned on or off. Of all things, eliminating that thump is my key priority as of current. Does anyone have anything else they could suggest to eliminate this?

 

[Adam]

Sorry if I missed your posts between when you got this sub and now, but I have a question for you.

Were you using the sub before without any thump or hum, and they both started only after a rearrangement of gear?

 

[Shintsu]

Sorry if I missed your posts between when you got this sub and now, but I have a question for you.

Were you using the sub before without any thump or hum, and they both started only after a rearrangement of gear?

Oh no, there weren't really any. I didn't have this sub hooked up and in position with the Polks (required some rearranging I hadn't gotten to that I did finally with these new Infinity speakers). I don't really recall hearing it humming or thumping when I temporarily hooked it up while I had the Polks but it was very brief.

I read somewhere that if you use a UPS that it can eliminate that thump, so I'm going to try that out with one of the APCs I have in the house. I hate reading that some people say it's normal and to get used to it - this is a violent thump that hardly sounds like something to just get used to...I will report back of success or not with the APC in a moment.

Okay, just hooked it up - no violent thump when powering on (hardly anything at all) and a much milder thump when turning off. The hum is still present, but disappears when not connected to the preamp. Removing the coax cable from the TV doesn't change it. Anything else I can do to remove that annoying hum, or is my wire the culprit? I mean, this is some decent looking Monster cable albeit not made to be a subwoofer wire it looks identical to Monster's actual subwoofer cable. I'm afraid I'll buy the cable from BJC and still have the hum (I have no LFE, only a L+R input and I'm simply using the L channel). Of course they're out of stock of the hard Y adapter that I'd like to use...

A stupid thing, but I'm not entirely sure that the subwoofer wasn't turned on before the preamp was which seems so obvious to me in afterthought. I fear to plug it back in to the power strip to see if it does the thumping again but the APC really doesn't look too well in here...I guess I'll give it a try again.

BAD IDEA. It still pops. Apparently the stupid APC is the solution for that popping problem. Dammit! Oh well. I question whether my "surge protector" is actually just a "surge supressor". Do you guys think something like this would work to stop the popping in my subwoofer?

 

[highfigh]

Okay, I finally rearranged things how I wanted and positioned my equipment the way I want but now the subwoofer is causing me a great deal of stress. Firstly, no matter what I do when I turn it on it thumps, when I turn it off it REALLY thumps. It sounds so god awful and scares me that it's just going to POP and then be dead. The subwoofer is only a polarized two pronger, not a grounded sub if that is of any relevance. It also thumps every time I turn my overhead fan on (including to adjust the speed).

Second, subwoofer hum!!! I've tried the old trick of undoing my coax cable to my TV to see if that mattered but it made no difference. The constant sound is driving me insane and is very annoying!

So, what can I do to solve both of these problems? The thump scares me the most, however the hum makes listening near impossible as it's a very noticable presence in anything I'm listening to. Someone told me that if I bought a power strip with EMI/RFI filtering this would eliminate the hum, however I have a fairly modern Cyber Power power strip that I thought had this but I couldn't say with certainty. Somewhere else I read that this kind of cable will make the hum stop:

What do I need to do to make both of these things stop? Both are driving me crazy!!

Ah, I think I found the model of the power strip I'm using. Looks exactly like this:

Apparently I do have an EMI/RFI filter on it...it's also 1250 joules rated if that matters at all.

If you hear a thump when you turn the fan on, you have problems that a grounded plug won't fix. Also, the hum is probably from the sub being on a different circuit from the rest of the system and most likely is on the other phase. If possible, find the breaker that powers the sub and swap it with one of the adjacent ones. It should fix both problems, but if the light/fan is on a 3-way switch and the sub's outlet is on the same one, don't do this. In that case, it would be best to run a new line from the same circuit as the rest of the system, to power the sub.

FYI- unless you don't have a cable box, disconnecting the coax from the TV will do nothing. What you would need to do is disconnect it from the cable box or get an isolator adaptor for the coax.

 

[Shintsu]

If you hear a thump when you turn the fan on, you have problems that a grounded plug won't fix. Also, the hum is probably from the sub being on a different circuit from the rest of the system and most likely is on the other phase. If possible, find the breaker that powers the sub and swap it with one of the adjacent ones. It should fix both problems, but if the light/fan is on a 3-way switch and the sub's outlet is on the same one, don't do this. In that case, it would be best to run a new line from the same circuit as the rest of the system, to power the sub.

FYI- unless you don't have a cable box, disconnecting the coax from the TV will do nothing. What you would need to do is disconnect it from the cable box or get an isolator adaptor for the coax.

Oh no, the fan is only a pull 3-way setup - the fan is the only thing that's 3-way in this room. The sub was plugged in to the same outlets that the rest of the system is plugged into but that still resulted in the thump. From my testing, the APC plugged into the power strip plugged into the wall outlet eliminated the violent thump. The rest of the audio components are plugged into the power strip. I could plug the preamp into the other outlet on the APC then everything would be on the APC (I have the components linked through each other so they won't power on unless the preamp is on) if that would give better results.

I do not have a cable box, my cable runs straight from the wall into my TV. If I were to buy such an isolator, how far back would it need to be? The original wire coming from outside, or just the wire that's in my room?

 

[TLS Guy]

Oh no, the fan is only a pull 3-way setup - the fan is the only thing that's 3-way in this room. The sub was plugged in to the same outlets that the rest of the system is plugged into but that still resulted in the thump. From my testing, the APC plugged into the power strip plugged into the wall outlet eliminated the violent thump. The rest of the audio components are plugged into the power strip. I could plug the preamp into the other outlet on the APC then everything would be on the APC (I have the components linked through each other so they won't power on unless the preamp is on) if that would give better results.

I do not have a cable box, my cable runs straight from the wall into my TV. If I were to buy such an isolator, how far back would it need to be? The original wire coming from outside, or just the wire that's in my room?

I find you posts very confusing. However I feel you have a ground loop causing the thumps and hum.

You need to unplug everything except speakers from your receiver. Then plug in the sub and see if you have hum. If you do then the problem is with the outlet your sub is plugged into or there is a problem with your subs power supply. I suspect however there will be no hum with no inputs connected to your receiver.

Now start plugging all you peripheral devices back into your receiver, starting with the TV. Note which unit, or units, when connected to your receiver bring back the hum and report back.

 

[Shintsu]

I find you posts very confusing. However I feel you have a ground loop causing the thumps and hum.

You need to unplug everything except speakers from your receiver. Then plug in the sub and see if you have hum. If you do then the problem is with the outlet your sub is plugged into or there is a problem with your subs power supply. I suspect however there will be no hum with no inputs connected to your receiver.

Now start plugging all you peripheral devices back into your receiver, starting with the TV. Note which unit, or units, when connected to your receiver bring back the hum and report back.

I don't see how they're confusing...but in any case, there was no hum with nothing plugged into the preamp. The CD player, Tape Deck, and TV all brought the hum back. The subwoofer is now plugged into the APC so there can't be anything wrong with the outlet on it. The only common factor in this is that same power strip which the APC is now plugged into. I would think the filtering in the APC would prevent any of that annoying hum...

I don't know if it's just my perception but the hum seems quieter now. It's still there and I want it gone though. Any other suggestions? The fan still makes the subwoofer pop when switching through the speeds despite going through the APC.

EDIT: APC apparently DIDN'T solve the thump - it's back now. I don't know what or why it didn't do it earlier but it is again so I'm taking the APC back out. Thump is still primary concern, if I leave it on constantly and turn the preamp off it makes violent thumps up and down - if I turn it off I still get the loud THUMP. I just don't get it. This is really pissing me off too.

 

[Shintsu]

Sorry to keep DPing...

I really didn't want to consider it given I just bought this and haven't used it really at all but is the subwoofer's age - or rather year of manufacture - any factor in this (1993)? The sound it makes when powered off sounds like it is powering down by pretty much letting all the power out of itself through the woofer in a violent high volume THUMP. I'm just guessing, but it seems like a newer subwoofer has more advanced technology that keeps it from just powering down through such a harsh method. Since most of you know a lot about all this stuff and I don't is there any truth to this? Or is this simply a matter of something malfunctioning within this subwoofer?

What I really don't get is why earlier I was able to get it to power off without a violent thump, but every other time it does. Given my reasoning, it should be thumping every time I turn it off but if it's able to power off without doing that and actually being fully powered on (not just turned on and right back off) that throws that whole idea in the trash. All this electrical stuff is consistent, so I'm at a loss here. Being illogical, the time it didn't thump I had the APC plugged into a different outlet on the same power strip and a different outlet on the APC - but that stuff is consistent and all of them work the same so there's no reason one outlet on the same piece of equipment should be any different than the other. If one did something, all of them would.

I'm willing to consider the subwoofer itself the problem and get a different one, but please help me make the determination as the true cause of this nasty thump. I know some amount of thumping isn't irregular when powering them off but this is too loud and not normal at all. My dad has a Definitive subwoofer hooked up to his Technics receiver and he never shuts it off and it doesn't thump or anything when the receiver is turned on or off - if I do the same the subwoofer thumps up and down. We have a super cheapo 10" Sony subwoofer in the living room and it doesn't thump when turning on or off so I don't understand the Energy's thumping.

If it is of any relevance, I have a Logitech Z-5500 speaker setup on my PC in the same room as my stereo with the Energy and it has a 10" sub but I never experience any thumping when switching through my ceiling fan's speeds or when powering the whole setup on or off. Someone I asked suggested that my room had too many things plugged in but I would think this would mean the Logitech subwoofer would do the same thing the Energy is doing - but it doesn't. I now recall the Energy made this same violent thump when I powered it off and it was plugged into a different power strip plugged into a different receptacle on the same wall outlet as the current one I'm getting the problems with (if that made any sense). It'll be a PITA, but if I determine that this is a serious possibility I'll drag the thing out of the corner again and put it in the other room and try it on the receiver in the living room (But I'd really rather fix the problem with it as it sits).

In the meantime, I'll look around and see what newer subwoofer alternatives there are within my price range ($200 and under). This thing is only a two prong plug as well - I thought newer subs were three prong?

I absolutely can't believe it, but the best deal I'm seeing for a subwoofer that isn't some off-brand low quality turd is the Polk PSW10 (The sub I cited as being a cheesy little thing). Newegg has it for $100 free shipping. I'm really starting to consider it if I have to buy a replacement sub, I don't see where I could get a better sub for $100 (especially new). I can't even find any good ones used for $200...

 

[TLS Guy]

Sorry to keep DPing...

I really didn't want to consider it given I just bought this and haven't used it really at all but is the subwoofer's age - or rather year of manufacture - any factor in this (1993)? The sound it makes when powered off sounds like it is powering down by pretty much letting all the power out of itself through the woofer in a violent high volume THUMP. I'm just guessing, but it seems like a newer subwoofer has more advanced technology that keeps it from just powering down through such a harsh method. Since most of you know a lot about all this stuff and I don't is there any truth to this? Or is this simply a matter of something malfunctioning within this subwoofer?

What I really don't get is why earlier I was able to get it to power off without a violent thump, but every other time it does. Given my reasoning, it should be thumping every time I turn it off but if it's able to power off without doing that and actually being fully powered on (not just turned on and right back off) that throws that whole idea in the trash. All this electrical stuff is consistent, so I'm at a loss here. Being illogical, the time it didn't thump I had the APC plugged into a different outlet on the same power strip and a different outlet on the APC - but that stuff is consistent and all of them work the same so there's no reason one outlet on the same piece of equipment should be any different than the other. If one did something, all of them would.

I'm willing to consider the subwoofer itself the problem and get a different one, but please help me make the determination as the true cause of this nasty thump. I know some amount of thumping isn't irregular when powering them off but this is too loud and not normal at all. My dad has a Definitive subwoofer hooked up to his Technics receiver and he never shuts it off and it doesn't thump or anything when the receiver is turned on or off - if I do the same the subwoofer thumps up and down. We have a super cheapo 10" Sony subwoofer in the living room and it doesn't thump when turning on or off so I don't understand the Energy's thumping.

If it is of any relevance, I have a Logitech Z-5500 speaker setup on my PC in the same room as my stereo with the Energy and it has a 10" sub but I never experience any thumping when switching through my ceiling fan's speeds or when powering the whole setup on or off. Someone I asked suggested that my room had too many things plugged in but I would think this would mean the Logitech subwoofer would do the same thing the Energy is doing - but it doesn't. I now recall the Energy made this same violent thump when I powered it off and it was plugged into a different power strip plugged into a different receptacle on the same wall outlet as the current one I'm getting the problems with (if that made any sense). It'll be a PITA, but if I determine that this is a serious possibility I'll drag the thing out of the corner again and put it in the other room and try it on the receiver in the living room (But I'd really rather fix the problem with it as it sits).

In the meantime, I'll look around and see what newer subwoofer alternatives there are within my price range ($200 and under). This thing is only a two prong plug as well - I thought newer subs were three prong?

I absolutely can't believe it, but the best deal I'm seeing for a subwoofer that isn't some off-brand low quality turd is the Polk PSW10 (The sub I cited as being a cheesy little thing). Newegg has it for $100 free shipping. I'm really starting to consider it if I have to buy a replacement sub, I don't see where I could get a better sub for $100 (especially new). I can't even find any good ones used for $200...

Which of your devices are two prong and which three? I need to know if your receiver is two or three prong, and which of your peripherals are three prong and which are two.

If I understand you correctly, there is no hum from the sub if it is not connected to anything, there is no hum if connected to your receiver, but there is you plug even one of any devices into the receiver you have hum. Is that correct?

One other thing when you have hum from the sub, see if there is any hum from your other speakers, when they are set to large. This will be an especially important piece of information.

By the way, in the price range you mention, you will be better off with no sub.

I'm getting the feeling there is a leak between the ground plane and neutral in the power supply of your sub, but I don't have enough data from you yet to determine if that is highly likely or not. This still may be a simple ground loop, and easily eliminated. Systems should be grounded at only one point.

 

[croseiv]

Isn't this sub the one you bought used recently for a very good price? I hate to say it, but maybe that's why it was so cheap. I hope not, but this is an older sub isn't it?

 

[just-some-guy]

did you try using an extension cord, running to a different circuit in another room ?

 

[Shintsu]

Yes, I did get a good deal on this subwoofer - however the guy who sold it to me is a friend of mine and wouldn't try to pawn it off on me if it were broken. He had a two week return policy but I took too long getting it setup to figure this out (shame that). It worked fine when we tested it and I don't recall any hum then. The sub is from 1993 as I said, which begins to make me question that thumping as being an inherent flaw from the age of it.

TLS, everything in my system is two prong. The Preamp, amp, CD player, tape deck, turntable, TV, all of it except the 360 which is hooked up to the TV. I thought the 360's three prong plug might have been messing with it but it was humming before I even plugged the 360 in to the outlet. Yes, what you said is correct about the hum when nothing is plugged in. And by "set to Large" I take it you think I'm using a receiver or preamp with such a setting - I am not. There's nothing in there for me to tell it the size of my speakers. I can hardly see no sub being a good alternative to a pair of bookshelves which lack low end without one. I play games and movies on this - point being I need bass for those things.

Just-some-guy, I haven't tried that but I'll give that a go as well. It won't matter if I can eliminate this hum if the sub still thumps when I turn it off - I'd just assume never turn it on in the first place if it's going to do that so for all intents and purposes I'd rather not even use it. It was playing at his house fine with no hum, it just seems to do it in my room.

 

[Shintsu]

When it is plugged into an extension cord on another circuit the violent thump is gone but the hum is still there. I have it on on an extension cord within my room and it didn't thump turning it on but it did thump when I turned it off. I'm thinking about buying a newer sub from bestbuy and giving it a test run and returning it regardless of if it thumps or not just to see if it's the sub or my room. Any other ideas? I tried running a ground wire from the preamp to the sub and it made no difference. Same going from the amp to the sub as well...

 

[highfigh]

Oh no, the fan is only a pull 3-way setup - the fan is the only thing that's 3-way in this room. The sub was plugged in to the same outlets that the rest of the system is plugged into but that still resulted in the thump. From my testing, the APC plugged into the power strip plugged into the wall outlet eliminated the violent thump. The rest of the audio components are plugged into the power strip. I could plug the preamp into the other outlet on the APC then everything would be on the APC (I have the components linked through each other so they won't power on unless the preamp is on) if that would give better results.

I do not have a cable box, my cable runs straight from the wall into my TV. If I were to buy such an isolator, how far back would it need to be? The original wire coming from outside, or just the wire that's in my room?

You would put the adaptor right on the end in the room with the equipment.

Is the power strip a surge suppressor, too? The APC should handle that, right? If it does, you don't want to have a suppressor plugged into a suppressor.

Does the sub turn on by sensing incoming signal?

 

[Shintsu]

You would put the adaptor right on the end in the room with the equipment.

Is the power strip a surge suppressor, too? The APC should handle that, right? If it does, you don't want to have a suppressor plugged into a suppressor.

Does the sub turn on by sensing incoming signal?

Hmm, well I would think unhooking my coax would make the hum stop if the coax were a problem. The only reason the APC was plugged into the power strip was due to the location - the plug is on the other side of my entertainment center and not easily reachable. The subwoofer is the only reason it's on this side and not the other because the cord isn't long enough. I thought the filtering in the APC might be stronger and better than the power strip since I knew the APC is a surge protector not just a suppressor but apparently that didn't matter it still thumped.

The sub only turns on by me pushing the soft touch button on the back. It's either on or off - no auto or auto sensing modes on it. I feel tempted to go up to Best Buy or some place similar and buy one to test out and see if it still makes the hum and thump. If I eliminate one or both I'll know it's something with this sub but if both are the same I'll know it's the setup.