My Subwoofer Hums. I tested disconnecting all my cables in my receiver and reconnecting them one by one. What I noticed is the hum is introduced in the HDMI sockets. I have a Onkyo 705 receiver and it has a HDMI out and 3 HDMI inputs. When I put a HDMI cable from one of my components into any of those HDMI sockets, the Humming is introduced. And the more HDMI cables I have plugged in, the Humming gets louder.

I got a Calrad Isolation Transformer from BlueJeansCable and connected it from my Subwoofer out on my receiver to my Sub cord. It had no effect. I also tried connecting the Transformer on the back of my Sub to the cord and it still didn't work.

Where can I go from here? Can anyone help?

I have a SVS PB10 NSD Sub.

Are you saying that you get a hum when plugging in different pieces of equipment into any hdmi input, or is it the same piece of equipment plugged into any of your hdmi inputs? A hum indicates a ground loop. Is all of your equipment on the same source (breaker) and is there anything else on this source besides your A/V equipment? Are you using one hdmi cable or different ones? You might try separating the power cords from the A/V cables.

Are you saying that you get a hum when plugging in different pieces of equipment into any hdmi input, or is it the same piece of equipment plugged into any of your hdmi inputs?

Any piece of equipment into any hdmi input. The equipment I'm plugging in via HDMI is my TV, HD DVD player, and CableBox/DVR.

A hum indicates a ground loop. Is all of your equipment on the same source (breaker) and is there anything else on this source besides your A/V equipment?

I have a Monster surge protector going into the outlet. All my A/V equipment is hooked up to the surge protector and nothing else.

Are you using one hdmi cable or different ones? You might try separating the power cords from the A/V cables.

I'm using different HDMI cables and it doesn't matter which one I use -- I still get the Hum.

What do you mean separating the power cords from the A/V cables?

Generally it is a good idea to not run cables that carry electrical current with cables that carry audio and video signal. A little bit of separation is best if you can. The outlet that the surge protector is on, what else is plugged into this same circuit? Find those items and unplug them one at a time to see if they are causing the problem. Things like microwaves and refrigerators can cause this. You might even remove your surge protector from the system to verify that it is not causing the problem. Do one item at a time and then check.

Try take a short or lengthy piece of wire that’s insulated and attach it to the screw fixings on one piece of equipment and attach to another and keep going though, what you have set up there soon or later you’ll find the little "electronic Gremlin" and then you’ll be happy.:)

weird

I just unplugged the surge protector from the outlet, so nothing was plugged into a power source anymore. Then I put my sub power cord into the outlet all by itself and it had a hum, although pretty quiet. I could feel the woofer vibrating and I could hear the hum. The sub was still connected to the receiver during this time though. If I break that connection, the hum stops.

Then I tested just having the receiver and sub in the outlet. The humming was pretty bad. When I started disconnecting the HDMI cables it got better.

weird

I just unplugged the surge protector from the outlet, so nothing was plugged into a power source anymore. Then I put my sub power cord into the outlet all by itself and it had a hum, although pretty quiet. I could feel the woofer vibrating and I could hear the hum. The sub was still connected to the receiver during this time though. If I break that connection, the hum stops.

Then I tested just having the receiver and sub in the outlet. The humming was pretty bad. When I started disconnecting the HDMI cables it got better.
Read my post in the 705 thread. This may be a receiver problem like mine was.

Unless it’s a major fault with the design could be the transformer is too close to the sub bass speaker and is causing humming to be received. Open the sub up, disconnect the power first mind you, and take a few pictures of what it looks like inside. Shouldn’t take you no more than 30 minutes.

I put it on Pure Audio and the hum went away almost completely. I had to turn it on max volume and my ear against the sub port to hear the hum.

im going to go out for lunch, ill try some of the suggestions here later

I put it on Pure Audio and the hum went away almost completely. I had to turn it on max volume and my ear against the sub port to hear the hum.

im going to go out for lunch, ill try some of the suggestions here later
Do yourself a favor and just exchange your receiver. I went thru exactly the same thing as you. Everyone one on the forum kept saying it was a ground loop problem but if that was true why would the hum go away when you switch to Pure Audio mode????? If you read the 705 thread there are a lot of people with noise of various types that disappear when you switch to Pure Audio. As soon as I switched to the 805 the hum went away, end of story.

Have you disconnected any and all CATV and/or satellite TV connections from your setup to see if the hum disappears? This is the most common source of ground loop hum.

If the sub has a 3-prong plug, have you tried a 3-prong-to-2-prong adapter (yes, a 'cheater plug') to see if the hum disappears. Although this is not a recommended long-term solution to the problem, it can help you narrow down the possibilities as to what is going on.

Everyone one on the forum kept saying it was a ground loop problem but if that was true why would the hum go away when you switch to Pure Audio mode?

Pure Audio mode may disconnect the video circuitry, preventing any cable TV-induced ground loops from affecting the audio circuitry.

Have you disconnected any and all CATV and/or satellite TV connections from your setup to see if the hum disappears? This is the most common source of ground loop hum.

If the sub has a 3-prong plug, have you tried a 3-prong-to-2-prong adapter (yes, a 'cheater plug') to see if the hum disappears. Although this is not a recommended long-term solution to the problem, it can help you narrow down the possibilities as to what is going on.

Yes, I have said that I disconnected everything from the receiver and then reconnected everything one at a time. I noticed when I reconnected the HDMI cables (whether it be my TV, HD DVD player, or Cable Box/DVR) the humming sound was introduced in my Sub.

The Sub is two prong.

Do yourself a favor and just exchange your receiver. I went thru exactly the same thing as you. Everyone one on the forum kept saying it was a ground loop problem but if that was true why would the hum go away when you switch to Pure Audio mode????? If you read the 705 thread there are a lot of people with noise of various types that disappear when you switch to Pure Audio. As soon as I switched to the 805 the hum went away, end of story.

I've read your posts in the 705 thread. Thanks for pointing me to that. My problem is exactly the same as yours.

I'm weary of exchanging it for another 705 only to have the same problem again. But I also don't want to spend $300 more for the 805. What should I do?

I've read your posts in the 705 thread. Thanks for pointing me to that. My problem is exactly the same as yours.

I'm weary of exchanging it for another 705 only to have the same problem again. But I also don't want to spend $300 more for the 805. What should I do?
Buy a Denon :D

weird

I just unplugged the surge protector from the outlet, so nothing was plugged into a power source anymore. Then I put my sub power cord into the outlet all by itself and it had a hum, although pretty quiet. I could feel the woofer vibrating and I could hear the hum. The sub was still connected to the receiver during this time though. If I break that connection, the hum stops.

Then I tested just having the receiver and sub in the outlet. The humming was pretty bad. When I started disconnecting the HDMI cables it got better.

Are you saying that nothing but your sub (no AVR) was plugged in to your electrical outlet and you heard a hum? If that is the case then it is not your AVR. If that is what happened then I think another piece of equipment (fridge, microwave, ect.) is causing the ground loop.

I've read your posts in the 705 thread. Thanks for pointing me to that. My problem is exactly the same as yours.

I'm weary of exchanging it for another 705 only to have the same problem again. But I also don't want to spend $300 more for the 805. What should I do?
If you are still in your 30 day exchange period I would try another one. At least that would tell you if it is all 705's or just a select few. Its seems like there are a lot of people on the 705 thread that tested for noise and some had it and some didn't so maybe you will get lucky and it will fix yours. If you mail ordered yours and don't want to go thru the hassle of mailing it back, go to CC and buy one to try and then just return it, then you will know for sure. They will give you your money back no questions asked. One other thing you can try is to turn the crossover knob on your sub down to a setting just above what you have your receiver set at instead of putting it at the max. This got rid of most but not all of the hum in mine but I do not know what affect if any this had on the bass response.

Are you saying that nothing but your sub (no AVR) was plugged in to your electrical outlet and you heard a hum? If that is the case then it is not your AVR. If that is what happened then I think another piece of equipment (fridge, microwave, ect.) is causing the ground loop.

Yes, the only thing connected to a power source was the Sub. But the Sub cable was still connected to the receiver. When I disconnected the link between the receiver and the Sub, the hum stopped.

I'm positive, the problem lies in the receiver.

If you are still in your 30 day exchange period I would try another one. At least that would tell you if it is all 705's or just a select few. Its seems like there are a lot of people on the 705 thread that tested for noise and some had it and some didn't so maybe you will get lucky and it will fix yours. If you mail ordered yours and don't want to go thru the hassle of mailing it back, go to CC and buy one to try and then just return it, then you will know for sure. They will give you your money back no questions asked. One other thing you can try is to turn the crossover knob on your sub down to a setting just above what you have your receiver set at instead of putting it at the max. This got rid of most but not all of the hum in mine but I do not know what affect if any this had on the bass response.

Yes, I bought it from Amazon and I'm still within my 30 days. I don't want to go through the hassle of getting another 705 and having the same problem. I just put in for a refund and I'm going with the 805.

The 705 is 37.3 pounds and the 805 is 61 pounds. Surely there's some stuff in there to make the 805 a lot better. :p

Yes, I bought it from Amazon and I'm still within my 30 days. I don't want to go through the hassle of getting another 705 and having the same problem. I just put in for a refund and I'm going with the 805.

The 705 is 37.3 pounds and the 805 is 61 pounds. Surely there's some stuff in there to make the 805 a lot better. :p
Let me know when you make the switch. I want to know if your problem goes away like mine did.

The 705 is 37.3 pounds and the 805 is 61 pounds. Surely there's some stuff in there to make the 805 a lot better.
a 23.7 pound elf


Let me know when you make the switch. I want to know if your problem goes away like mine did.
Yeah, I'm curious, too. I definitely have my doubts.

I'll keep you guys updated.

I got the 805 from Amazon with 1 day shipping, so it will be here tommorow. I'm upset that they didn't have it in black and it said it would be 4 to 6 weeks. So I had to go with the silver :(

Yes, the only thing connected to a power source was the Sub. But the Sub cable was still connected to the receiver. When I disconnected the link between the receiver and the Sub, the hum stopped.

I'm positive, the problem lies in the receiver.

The problem has to be the AVR or the sub. Were you able to plug your sub into another AVR to confirm that it is not the sub? Though I tend to agree with you that it is probably the AVR. I have the 805 and it is a good AVR. Just make sure that you have good ventilation since it gets hot in cramped quarters. The 705 probably does the same thing so I bet you already know this.

The problem has to be the AVR or the sub. Were you able to plug your sub into another AVR to confirm that it is not the sub? Though I tend to agree with you that it is probably the AVR.
Why does it have to be either? There is a good chance that it is related to something 'electrical' and that there is nothing at all wrong with either his sub or the 705. And even if the 805 fixes the issue, that still doesn't mean that it was due to there being something wrong with the 705. The 805 may be somehow more resistant to electrical interference or ground loops. Either way, though, if the 805 fixes the problem, he IS 'gold'. It's just an expensive way to get around an electrical issue if that's what it really is (was).

Why does it have to be either? There is a good chance that it is related to something 'electrical' and that there is nothing at all wrong with either his sub or the 705. And even if the 805 fixes the issue, that still doesn't mean that it was due to there being something wrong with the 705. The 805 may be somehow more resistant to electrical interference or ground loops. Either way, though, if the 805 fixes the problem, he IS 'gold'. It's just an expensive way to get around an electrical issue if that's what it really is (was).

You should try reading the posts in the 705 forum and you might become convinced.

The problem has to be the AVR or the sub. Were you able to plug your sub into another AVR to confirm that it is not the sub? Though I tend to agree with you that it is probably the AVR. I have the 805 and it is a good AVR. Just make sure that you have good ventilation since it gets hot in cramped quarters. The 705 probably does the same thing so I bet you already know this.

I had just bought the 705 October 1st. I didn't have this issue with the AVR before it.

I'm worried that the 805 might warm up my room too much. I don't get good air conditioning in here during the summer.

Try taking the gound post off your plug. I had the same problem with my sub and it was a ground loop. I bought a $1 ground to non ground adapter and it went away.

Well guys, got the Onkyo 805 today and hooked it up. Hum is gone!!! :D

Even at Max volume there is no Sub Hum at all. I don't know if I had at faulty Onkyo 705 AVR or if they all have problems, but I'm glad that's now over with.

I suggest anyone with a Onkyo 705 test for Hum. The easiest way to detect this is to have a sound source playing for 10 seconds or so and then switch to a source where no sound is coming out. As you turn the volume up, you should hear a Humming from your Sub get worse -- if it's also faulty like mine. It seems other's in the 705 thread have had this exact same issue.

Thanks for all the replies to my thread here.

Well guys, got the Onkyo 805 today and hooked it up. Hum is gone!!! :D

Even at Max volume there is no Sub Hum at all. I don't know if I had at faulty Onkyo 705 AVR or if they all have problems, but I'm glad that's now over with.

I suggest anyone with a Onkyo 705 test for Hum. The easiest way to detect this is to have a sound source playing for 10 seconds or so and then switch to a source where no sound is coming out. As you turn the volume up, you should hear a Humming from your Sub get worse -- if it's also faulty like mine. It seems other's in the 705 thread have had this exact same issue.

Thanks for all the replies to my thread here.
I am glad to see that this fixed your problem just like mine. You should post your results in the 705 thread as it seems there are a lot of skeptics over there also who think that there is nothing wrong with the 705 and a few people who were on the fence as to whether they should exchange their receiver or not . Also what are your first impressions of the 805.

I am glad to see that this fixed your problem just like mine. You should post your results in the 705 thread as it seems there are a lot of skeptics over there also who think that there is nothing wrong with the 705 and a few people who were on the fence as to whether they should exchange their receiver or not . Also what are your first impressions of the 805.

Ya, first thing I did was make a post over in the 705 thread to give some insight to this problem and maybe help anyone who has the same issue.

The 805 is huge and doesn't fit under my TV stand, lol. I guess it's time for me to get an A/V Rack.

I'm loving the 805. It may be just placebo but to me the sound is coming out a lot more clean. It has a crispness to it that I'm enjoying. I like the onscreen display better than the 705 and how it shows a diagram of what speakers are in use. Connecting the speaker wires were easy. I like how all the connectors were on the bottom all lined up horizontally. No Hum was a good feature they put in the 805 too.

.....................if the 805 fixes the issue, that still doesn't mean that it was due to there being something wrong with the 705. The 805 may be somehow more resistant to electrical interference or ground loops. Either way, though, if the 805 fixes the problem, he IS 'gold'. It's just an expensive way to get around an electrical issue if that's what it really is (was).
;)

Yes, I guess I AM a skeptic, not to be ornery, but because I know that things are not always what they seem.