Humming from Speakers

swiftflo

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We have a "panel" type JVC TV. Both my wife and I suffer the same problems with the sound from the TV. When listening to the news we do not have problems understanding what the announcer is saying, but when watching a film or sometimes a play neither of us can understand what is being said, we hear someone is speaking and the sound is okay for volume, it's just that we cannot decipher the words.
So in my wisdom(?) I decided to add two extra speakers to the setup. I had two speakers in store so I connected one up to the power and to the "earphone" plug on the tv and then connected the two speakers together via the cable from the second speaker.
I placed the speakers one either side of the tv and virgin tivo box (tried on the floor and also on the shelf of the tv stand), no matter where I placed the speakers there is a quite load hum from them.

Is there anyway to cure this humming or do I need different speakers, these speakers ar what I once had connected up to a PC. (Don't laugh).
 
Qs for clairification: Are you using the headphone jack because that's the recommended way to hook up a sound bar per the TV manual? Also, are these powered PC speakers that you are plugging into an AC power outlet? And using the headphone jack as the sound source? Are there any other connections from the TV for sound?
 
Qs for clairification: Are you using the headphone jack because that's the recommended way to hook up a sound bar per the TV manual? Also, are these powered PC speakers that you are plugging into an AC power outlet? And using the headphone jack as the sound source? Are there any other connections from the TV for sound?

I am using the headphone jack because that is the connection from the cable on the speakers.

Yes the speakers are Powered speakers plugged into a AC power outlet.

Yes using the headphone jack as the sound source.

No there are no other connections from the TV for sound.
 
I am using the headphone jack because that is the connection from the cable on the speakers.

Yes the speakers are Powered speakers plugged into a AC power outlet.

Yes using the headphone jack as the sound source.

No there are no other connections from the TV for sound.

Just found that there is a Digital Audio output socket on the rear of the set, but the jackplug on my speakers will obviously not fit this.
 
not the ideal set up obviously.... but a couple of suggestions would be; first try plugging the power into another outlet in the room to see if that helps, it could be a ground loop. Next you should try moving the speakers away from the TV etc and to see if that has an impact to determine if it is a shielding problem. After that I'd check to see if the headphone jack or wire itself is bad.... make sure the jack is inserted fully, wiggle the jack and wiggle the wire... are you getting adequet volume from the speakers or too much?
 
not the ideal set up obviously.... but a couple of suggestions would be; first try plugging the power into another outlet in the room to see if that helps, it could be a ground loop. Next you should try moving the speakers away from the TV etc and to see if that has an impact to determine if it is a shielding problem. After that I'd check to see if the headphone jack or wire itself is bad.... make sure the jack is inserted fully, wiggle the jack and wiggle the wire... are you getting adequet volume from the speakers or too much?

Can only agree with you over the setup, but was trying for a quick fix (cheap). However I will certainly try all you suggestions and yes the volume from the two speakers is just about right.

How about if I get a amp, say from off ebay, with the digital audio connection and connect my speakers to that ??.
 
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Can only agree with you over the setup, but was trying for a quick fix (cheap). However I will certainly try all you suggestions and yes the volume from the two speakers is just about right.

How about if I get a amp, say from off ebay, with the digital audio connection and connect my speakers to that ??.

Just to expand on what Jim suggested, have you tried reconnecting these speakers to another source (eg. laptop). If the hum is being produced by the headphone output of the TV then the only solution would be to use the digital connection with another setup.

If you were to buy an amp of ebay with a digital input then you would also need some passive speakers to drive as the current pair you have are active.
 
Can only agree with you over the setup, but was trying for a quick fix (cheap). However I will certainly try all you suggestions and yes the volume from the two speakers is just about right.

How about if I get a amp, say from off ebay, with the digital audio connection and connect my speakers to that ??.
Since you're using PC speakers, which already have internal amplification, and your TV has a digital audio output connection, all you need is a simple little converter to sit between them, like this, a digital connecting cable and a 3.5mm - 2xRCA adapter.
 
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A £10 hum blocker will cure the problem. These can be bought from Car Audio retailers and electronics shops, with the correct (mini jack-mini jack) connections.

I would try this first as a cheap fix.
 
Can't help on the hum, though I have exactly the same setup on the kitchen Bush TV with no problems. Sounds like a bad ground connection somewhere. Check the TV output with actual headphones and then the speakers on a PC headphone output.
I would agree that film soundtracks can be challenging. Even some Blue Ray versions sound like they're stuck up a street drain. The films back in the 50s-70s were much superior technically as they seemed to know what they were doing back then. Hi Fi surround speakers help a lot. My aging ears don't work much above 12 kHz any more but that's probably not the main problem with soundtracks.

PS. it would be good to compile films with the worst sound. Quantum of Solace and Tinker Tailor Soldier Spy weren't too good.

luggsie
 
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Can't help on the hum, though I have exactly the same setup on the kitchen Bush TV with no problems. Sounds like a bad ground connection somewhere. Check the TV output with actual headphones and then the speakers on a PC headphone output.
I would agree that film soundtracks can be challenging. Even some Blue Ray versions sound like they're stuck up a street drain. The films back in the 50s-70s were much superior technically as they seemed to know what they were doing back then. Hi Fi surround speakers help a lot. My aging ears don't work much above 12 kHz any more but that's probably not the main problem with soundtracks.

PS. it would be good to compile films with the worst sound. Quantum of Solace and Tinker Tailor Soldier Spy weren't too good.

luggsie

Thanks for your suggestion to try with headphones, tried this and no there is no humming with the earphones. Cannot try with my computer as its a mac and it does not have a mini jackplug.
 
A £10 hum blocker will cure the problem. These can be bought from Car Audio retailers and electronics shops, with the correct (mini jack-mini jack) connections.

I would try this first as a cheap fix.

Thanks for your reply, will get a hum blocker and try it.
 
Update on humming from speakers.

As I said earlier connected headphones to jack connection on TV and there was no humming. Connected the speakers to a PC and there was no humming.
It seems as if the humming is coming from out of the speaker that the power goes to.
Will a hum blocker still do the trick.
 
Yes, it sounds like the power supply in the TV is dumping noise to earth. As headphones do not have an earth, there is no hum, but with the speakers, there is a connection, hence the buzz.

Humbuckers or hum blockers isolate the audio, so there is no earth path. This cures the hum in a stroke.
 
It may be the TV output is "grounded" internally to a floating earth, ie a pair of bypass capacitors, one going to live and the other to neutral. So it's actually floating at 120v AC (quite safely as the capacitors are very small value). Connecting the ground sleeve of the stereo jack to the real ground on the 13Amp mains socket might fix it (and cost nothing). This effect happens a lot on microphones connected to mains powered preamplifiers or laptops.
 
It may be the TV output is "grounded" internally to a floating earth, ie a pair of bypass capacitors, one going to live and the other to neutral. So it's actually floating at 120v AC (quite safely as the capacitors are very small value). Connecting the ground sleeve of the stereo jack to the real ground on the 13Amp mains socket might fix it (and cost nothing). This effect happens a lot on microphones connected to mains powered preamplifiers or laptops.

Sorry but you are losing me with this explanation, can you explain in more detail what the procedure is.
 
Modern TV audio should not be grounded, having decent power supplies...but OP hasn't told us what this TV is - is it a CRT (old tv) or a more modern LCD/digital?

PC speakers aren't much good, although if placed near yr ears may add some clarity, which is not affected by the room acoustics.

Modern "processing" has been blamed for poor speech-recognition, ie when a film contains music, the chips have to apply the "music" process to the speech as well.
Have you tried to switch off music-processing?
I'd expect a simple Stereo set up will have the greatest clarity, although adding some bass reinforcement will provide some "fun" as well . . . . I think the secret is to have some hf speakers (ie tiny ones), near your ears so the music coloration is subdued .
. . . but as with nearly all things . . . Only you can work this out for your setup.

Good luck....
 
Modern TV audio should not be grounded, having decent power supplies...but OP hasn't told us what this TV is - is it a CRT (old tv) or a more modern LCD/digital?

PC speakers aren't much good, although if placed near yr ears may add some clarity, which is not affected by the room acoustics.

Modern "processing" has been blamed for poor speech-recognition, ie when a film contains music, the chips have to apply the "music" process to the speech as well.
Have you tried to switch off music-processing?
I'd expect a simple Stereo set up will have the greatest clarity, although adding some bass reinforcement will provide some "fun" as well . . . . I think the secret is to have some hf speakers (ie tiny ones), near your ears so the music coloration is subdued .
. . . but as with nearly all things . . . Only you can work this out for your setup.

Good luck....

The TV is a modern LCD/Digital as can be seen from my original post.(Panel TV)
 
"Sorry but you are losing me with this explanation, can you explain in more detail what the procedure is."

Apols, I may be on the wrong track here but when I use metal cased microphones on a mains powered pre-amp I often get a lot of hum. It's caused by mains noise getting onto the casing of the preamp and microphone screening and can be removed by connecting the pre-amp metal case to the mains earth on the 13A plug. There is normally a screw-up ground terminal provided on the pre-amp case to enable this. Definitely not recommended if you're not happy with fiddling with mains connections !

The guys who do music gigs and PA systems always get this problem with microphones and laptops generally as the plastic cased power supplies that laptops come with don't have any earth connections as a rule. They just have to get expert at fixing hum problems.

luggsie
 
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Pros do not get hum off mics because we used balanced line and connect the earth at the receive end only. We do this all the way down the line, right to the amps. I have never had to connect the signal earth to the mains earth in 20 years of pro audio, including splitting out to OB vans and recording rigs.

If you are getting mic hum, you have unbalanced mics and inputs or incorrect wiring.

To prevent laptop noise, you need to isolate the signal earth from the mains earth to prevent the functional earth noise from the power supply coming through. a £10 audio isolator fitted between the headphone output and speaker input is usually fine. It contains a transformer that totally isolates the input and output, so no noise. For instruments that have similar problems, we use a D/I box that does the same job, but has attenuation switches and different connections.
 
A few posts back I suggested using the TV's optical output through a simple DAC (link given) to your speakers as a cheap solution to all of your problems. Hum blockers can work, but an optical connection eliminates the cause of ground loop hums by removing the electrical path that gives rise to the problem in the first place.
 
A few posts back I suggested using the TV's optical output through a simple DAC (link given) to your speakers as a cheap solution to all of your problems. Hum blockers can work, but an optical connection eliminates the cause of ground loop hums by removing the electrical path that gives rise to the problem in the first place.

Thanks you for your input, your remedy is the one I will be using.
 
"noiseboy72: Pros do not get hum off mics because we used balanced line and connect the earth at the receive end only."

All sounds reasonable, but this is consumer-level kit rather than professional so not sure it's relevant. Am totally
nonplussed by the problem as I've used the headphone outputs on a Bush, two LG's, big Panasonic, little Alba, UMC and Sainsbury's Celcius, all squawky panel TV's, then input to PC speakers (two types), Roland Monitors, AV Amp, and Stereo amp (the latter two earthed) and never got a hum problem apart from when the stereo jack gets accidently pulled half-way out of the TV socket. If he went the optical route the TV's volume control won't work which is annoying. Perhaps the OP has an MP3-capable mobile or smart phone he could plug his PC speakers
into to test them.

luggsie
 
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Am totally nonplussed by the problem as ...
TV-sourced hum problems are normally, although not always, caused by ground loops between the aerial feed (cable, satellite, Sky, Freeview, whatever) and the rest of the kit. In the case of satellite (including SKY) it's installation dependent, on whether the installation has been carried out correctly or not.

The other major cause is the PC, but here too it's not a universal problem.
 
Hum isn't the problem it was, mainly diue to use of switch-mode PSUs, which operate at high frequencies. This has some cost advantage, since much smaller capacitors can be used. As a result of this TV circuitry is isolated from mains.



However, I've experienced an odd effect, just last week, and only for about three hours:-
. . I was watching telly (with Audio thro ext amp+speakers, taken from Headphone o/p of the telly (there being no other op, although it does sport a sub-out [but it's not very sub to my ears]).
When watching TV program which was largely music background I'm hearing voices - not clear enough to interpret, but obviously in English and like a walkie-talkie....sor of babble.
Now this can be vared in volume by raising the Amp volume, but not by changing the Telly's volume . . . yet by disconnecting the headphone jack it's gone and there is no hint of it on the telly (internal speakers) and nothing on the amp . Moving the input lead about makes no difference and when it was "talking" there was no effect trying to screen the cable, or wrapping it into a loop (it's quite long) . . . . .

Turning the telly volume to zero (via Remote), doesn't affect the "talking" and switching the telly off doesn't kill it either . . . only pulling the audio jack will silence it (completlely)...

Oddly I've not heard this (breakthrough) before and it stopped about two hours later. The recorded program was perfect, with no hint of a fault. As a check for input-layout, I tried moving the input (to the amplifier) to another switched position and that made no difference.

Really odd - but am glad it's gone . . . . I wonder if a neighbour had friends in a nearby garden (it was a rare good weather-day), and they were talking to mates on a shortwave radio, or a cheapo walkie-talkie intended to be used on a countryside ramble (ie away from domestic Audio/TV's) .

Anyone else experienced this? - and any suggestions should it come back???

The ext amp+Speakers are perfectly OK before and since, with no noticeible distortion, or hum.

Odd, that.
 

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