View Full Version : Irritating humming of the sub - too loud?
Does your sub hum? My Eltax Stargates (the dub is the A8) does. It's my 1st sub and I just wonder ed if they all do.
Quite off putting, especially with quieter scenes and diologue. Any ideas?
Having the same problem with minw (just set up on Saturday) - posted in this thread:
http://thedvdforums.com/forums/showthread.php?s=&threadid=40647
Tried moving, different leads etc but it is very noticeable. As a novice to this sort of setup, I to would like any advice.
homerjhandley
17-12-2001, 21:09
I had this problem (jamo 410e)
I just used a different lead.
The one i found worked was a single one from the amp and a phono splitter used @ the sub end.
:D
My sub hummed quite a lot until I turned it down until the hum disappeared and then boosted the signal from the amp. I still get the same amount of rumble but no hum.
Problem I have is that even with connection to line input unplugged the amp still hums and thats with all levels turned right down. Tried isolating completely away from any other equipment but still have the same effect. I would say iys very noticeable and really does distract when watching tv/films etc.
lovegroova
18-12-2001, 10:10
You may be experiencing a ground loop. Try disconnecting the 'earth' wire in the mains plug and see if the hum disappears...
K sorted.
My sub has 2 ways u can connect it. One is with a cable from the amp to the sub. The other is by connecting the left and right speakers to the sub then on to the amp.
I tried the latter and the humming has dropped right down. Try that Bossc@. I might also try groova's idea.
The humming was certainly to do with the sub and the cable connection, because when it was on and not connected to the amp, it still hummed and louder if u touched the amp end of the connecter. Altering the loudness never affected the hum, though inceasing the frequency did.
Cheers lovegroova
think I'll try that - as I said the hum comes as soon as its powered up. It doesn't have to be connected to the amp.
Cheers for help all
Just checked when I got home and the earth is not connected anyway. I have tried just the sub seperately in a different room and the humming is still there. Bit lost now.
The advice I was given was to take it to a friends house in another neighbourhood and try it there. I did and my 5th sub from Videologic still hummed. Videologic bought it back from me.
I have tried for 12 months to find a way round this hum but no luck so far. I think I`ll just stick with my Mission speakers.
I found by moving wires about (so they were not running along side power leads etc) and removing the TV co-ax input from the telly (ie. taking it out the RF socket) that the hum from the sub and buzz coming through the speakers at least was reduced.
Seems to be back atm tho :rolleyes:
Btw, I've got a digitheatre (everyone seems to have this problem!).
Cheers to all for the responses. I've ensured that the power is not running alonside the input - next thing to try is to disconnect all components and then add one at a time to see if that helps. Going to also try round a mates house to see if that makes any difference.
Just a shame that afyer buying new DVD and amp and speakers that this one element spoils the effect. I anticipated some low level noise from the powered sub but this is really off putting. Its always there in the background and is audible all the time. Just spoils the whole effect as I'm completely happy with everything else.:mad:
I am experiencing a similar problem at the moment with my kef PSW1000 active sub. Its plugged into the subout off my pioneer 859. I use a IXOS high quality lead, going into the Left line-in on the sub.
It was all working fine when i first set it up, but now i get such a loud buzzing interference everytime the sub is activated its unusable.
The interference appears to be coming down the cable from the amp, and is just like a power-hum sort of interference.
The only thing i can think which is different is that had a play with the "peak bass level" setting. But, the sub sounded fine after that. I also fitted gold plated banana plugs to all the speaker cables.
I have since cancelled the "Peak bass level" setting, and had a play with all the other settings i can find, and it doesnt make any difference. Ive also tried moving the sub to a different position in the room, and used a different cable. Ive also tried switching the input on the sub from auto to manual, and altered the gain settings on the sub. Ive moved the amp away from the telly, and turned off/removed anything which i thought might cause any interference.
The only thing i havent tried is to check that the earth plug isnt connected in the powerlead in case theres a ground loop.
Can anyone think of anything obvious which ive done or what it may be? As its really anoying to have a nice sub sitting there and not being able to use it.
Cable Monkey
20-12-2001, 10:45
Give the audio lead a mechanical test (a good waggle!) or use another lead. I had a problem similar to this with a Sony sub. The lead was the faulty element.
As i read more I'm beginning to think that the sub itself may be at fault.
My problem is that even when the sub is stood alone in a seperate room, no connections to anything but purely powered on then I get the hum. When stood alone and powered , adjustment of level or volume does not make any impact on the level of the hum.
Should it hum at all if its not connected to the amp and just powered up?
The thing is that subs are specifically designed to reproduce low frequencies. mains hum (50Hz) falls right into their design range. It sounds like like poor power supply design and/or poor decoupling between the power supply and the inbuilt amplifier.
Have you tried short circuiting the phono input socket on the sub? If the hum goes away this indicates poor decoupling. Quite honestly, if you've tried everything else, it sounds like a defective sub - it's either a Friday afternooner or it's characteristic of the model.
Best advice? Change it.
Right - maybe getting to the bottom of this. At the mo I have TV, DVD, AMP and NTL cable all connected (as well as the sub) Just checked all the leads from the appliances and the only one that has a metal pin on the earth is the cable box!! But I'm not wholly convinced that this is connected. All the other appliances are definitely two wire only.
Would the cable box act as the ground in this case?
Sorry if this a bit dense!
:confused:
Originally posted by bossc@
As i read more I'm beginning to think that the sub itself may be at fault.
My problem is that even when the sub is stood alone in a seperate room, no connections to anything but purely powered on then I get the hum. When stood alone and powered , adjustment of level or volume does not make any impact on the level of the hum.
Should it hum at all if its not connected to the amp and just powered up?
If the sub hums/buzzes when powered on with nothing at all connected to it, then the fault isn't likely to be a ground loop.
Far more likely is what neon suggested - either a dodgy PSU design, or else a faulty component (to be honest, Kef stuff is usually pretty good, and the fact that it once worked without humming would seem to suggest at least a reasonable design - unless there is a design issue causing an early life failure on one of the components)
It's also possible, that a ground loop originally caused the problem, but is not the problem in itself. Ground loops can cause some very high currents to flow, and can damage equipment.
They are caused by two devices being grounded, with their respective grounds not being at the same potential (or voltage).
Ground is supposed to be 0V (in an ideal world), but if one device is at 0V, and the other's ground is even at 0.1V, then current will flow along the ground wire if those two devices are connected with say a phono lead (centre signal wire, and outer shield which is also the ground). Even if the shield had an end to end resistance/impedance of 0.1 Ohms, it would still cause a 1A current to flow.
There are several ways to eliminate this (although I wouldn't recommend simply disconnecting the earth connector in the mains lead of a device designed to have a safety earth).
The simplest is to simply disconnect the cable shield at one end - although this may cause the cable to effectively become unshielded at certain freqs, it may though, not really be much of an issue on a subwoofer signal cable, as the cable is only carrying signals between 20-120Hz (RF interference for instance, starts at several hundred KHz, although it's harmonics can go a lot lower). Only low frequency EMI might be a problem - although even that's not very likely in the average house, and can be avoided in most cases by carefully routing the cable away from the source of the interference.
Thanks for all your advvice (and to AET for letting me hijack the thread) Think I'll be returning the sub after all. Had a good play last night but nothing I did seemed to make any difference.
:(
np :)
BTW, what make is it?
Its a pioneer S-W80S - been spending my time at work searching for any reviews or forum comments but can't find any.
Originally posted by bossc@
Thanks for all your advvice (and to AET for letting me hijack the thread) Think I'll be returning the sub after all. Had a good play last night but nothing I did seemed to make any difference.
:(
My cheap and cheaful digitheatre had a hum. Its was definately earth/grounding related, I cured it by wiring up an earth wire to a copper pipe on a central heating radiator, the cable was then connectrd to the outer shielding cable on one of the inputs to the sub.
Just set up my new system and found the sub has a hum and then found this thread.
Mine is the same as the original poster i.e Pioneer S-W80S.
Did anyone find a solution with this model ?
Sorry for resurrecting this thread but did anyone find a solution to this problem?
I've just go a Paradigm PDR10 and found that it hums as soon as it powers on even with nothing connected to it.
Got a celestion S80, and i get hum.
When i got it, it had no manual, so I phoned richersounds to get them to send it on, and i happened to ask about hum, and the bloke said it's often sourced from the amp, which in my case is true.
If I unplug the cable amp end, it's gone, even with the rest of the cable connected to the sub.
lycanthrope on the loose
12-05-2002, 19:05
hmmmmmmmmm
I have also got a celestion s80 connected to my sherwood amp and I have also noticed a hum from the sub even when all sources and the amp is switched off and the sub is the only thing on I definately think in my case it is power supply related as I have just moved house and noticed the hum as soon as I powered up the amp where as in my old house I never noticed the hum.
The work around I used was to unplug the direct connect cable from the amp to the sub (sub out) and use the signal sourced from the front right and left speakers to power the sub. Front left and right go to the sub first, then on to the satellite speakers from there.
This was the alternative connection possibility from the Eltax manual for when amps didn't have their own sub out connection.
The hum is negligable now, though not sure if I'm losing perfomance as a result.
Originally posted by AET
The work around I used was to unplug the direct connect cable from the amp to the sub (sub out) and use the signal sourced from the front right and left speakers to power the sub. Front left and right go to the sub first, then on to the satellite speakers from there.
This was the alternative connection possibility from the Eltax manual for when amps didn't have their own sub out connection.
The hum is negligable now, though not sure if I'm losing perfomance as a result.
It think this setup will mean that you are not actually getting the .1 signal from a 5.1 source. All the sub will be doing is 'filling in' the bottom range for your main speakers.
puddleduck
15-05-2002, 21:03
I had this problem with my first sub - a Tannoy Saturn.
There was an always present electric humming type noise even when the sub was turned on, with no input. I got a replacement and this had the hum as well, so I traded up for a REL Q50, and I've got no hum now.
I think a lot of it is to do with poor quality power supply isolation - proximity to the TV also caused the hum to increase.
Originally posted by AndySymbian
I had this problem with my first sub - a Tannoy Saturn.
There was an always present electric humming type noise even when the sub was turned on, with no input. I got a replacement and this had the hum as well, so I traded up for a REL Q50, and I've got no hum now.
I think a lot of it is to do with poor quality power supply isolation - proximity to the TV also caused the hum to increase.
Poor PSU and internal amplifier design is the most likely cause of budget subs humming IMO.
To be fair, poor is perhaps a bit strong, as these units are built down to a price. If you pay £70 for a sub, be honest about what you are expecting to get. To be able to hit that kind of street price, gross design compromises are inevitable.
There is no excuse however for a £500 unit to be doing this noticeably - that is poor design/manufacture.
Practically all subs, except perhaps expensive purist designs, will hum to some degree - with some it's hardly audible unless the room is silent and you stick your ear right up to the unit, while with others it's easily heard and is annoying.
Best advice is to try before you buy.
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