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View Full Version : Question about noticeable abnormal sub noise...normal??



brazosdog02
04-08-2014, 05:26 PM
I have a pair of LV12 subs. When listening to one particular movie, there is a very noticeable 'whirring' noise coming from the subs. Its not a hum or a whine.....its in between and sounds like background wind noise but its not. What in the world is it and how do I stop if its not normal? There is also a 'hum' although very subtle. Im trying to verify if it does it with just this movie or what.


When the movie is PAUSED OR MUTED there is no noise whatsoever. It seems to do it with both BD and Dish sources. What is the deal???

curtis
04-08-2014, 10:55 PM
Can you tell us the name of the movie?

brazosdog02
04-09-2014, 06:16 AM
The movie is Frozen. I have kids...we watch that thing all the time. I simply attributed the noise to background wind but it seems to do it on quiet scenes that are not outdoors and it does it from my cable box as well. Both sources exhibit it and both have LFE feeds. Not sure how to troubleshoot. I have ALL of my AV equipment on a single 20A circuit, but last night I moved the subs to a separate circuit....I can't tell if that had any effect and Im not sure this is even ground loop noise since it goes away when paused or muted. No idea how to troubleshoot it or if its just normal. Its a strange white noise.

davef
04-09-2014, 11:32 AM
The movie is Frozen. I have kids...we watch that thing all the time. I simply attributed the noise to background wind but it seems to do it on quiet scenes that are not outdoors and it does it from my cable box as well. Both sources exhibit it and both have LFE feeds. Not sure how to troubleshoot. I have ALL of my AV equipment on a single 20A circuit, but last night I moved the subs to a separate circuit....I can't tell if that had any effect and Im not sure this is even ground loop noise since it goes away when paused or muted. No idea how to troubleshoot it or if its just normal. Its a strange white noise.

If you are hearing this background noise from Frozen using two different sources (DVD and cable), it is in the soundtrack. Speakers and subwoofers simply reproduce what is being sent to them. If there was something wrong your equipment, you would hear this same noise regardless of what movies was being played and it would be continuous.

If you had a ground loop, you would hear it throughout any source being played and even with no source.

brazosdog02
04-09-2014, 12:15 PM
No...thats not what I meant. I mean i get the noise from the BD watching Frozen, but I get it from Cable box too....when watching anything. I mean that the noise is independant of the movie being player. Sorry.

The noise is continuous as long as I do not mute or pause a movie or cable box. When paused or muted...all noise stops...even the white noise sound.

So, the noise coming through the Sub is either normal, or it is resulting from something the AVR is doing. I guess teh AVR could be 'defective' but its new and not cheap. It may have done this all along, but since I have not listened to my system at these levels before, I did not notice it. Perhaps another lead on Audyssey causing it is valid.

davef
04-11-2014, 12:05 PM
No...thats not what I meant. I mean i get the noise from the BD watching Frozen, but I get it from Cable box too....when watching anything. I mean that the noise is independant of the movie being player. Sorry.

The noise is continuous as long as I do not mute or pause a movie or cable box. When paused or muted...all noise stops...even the white noise sound.

So, the noise coming through the Sub is either normal, or it is resulting from something the AVR is doing. I guess teh AVR could be 'defective' but its new and not cheap. It may have done this all along, but since I have not listened to my system at these levels before, I did not notice it. Perhaps another lead on Audyssey causing it is valid.

Are you only hearing this while watching Frozen?

brazosdog02
04-11-2014, 12:35 PM
No. It doesn't seem to matter what im watching. If there is an LFE feed, I can hear it, but it has to be up around -25 or louder to hear clearly.

brazosdog02
04-11-2014, 03:11 PM
I had a chance to mess with it more. Turning off Audyssey does not make it go away. It diminishes it somewhat though. TUrning the trim levels on the sub down from -.5 also diminishes it. The Volume on the subs themselves are set to about 2 and 3 oclock on each sub. Im able to 'pause' previews and get it to make the noise. At reference levels, you can hear this white noise sound EASILY from 15' away. I guess its normal. I have moved wires and played with settings. I can't get it to go away. No other speakers make the noise. Even at the beginning of the movie, when it kicks in, there is also a hum that is audible. I don't know. Im not happy about it because its audible and Im not sure it should be but I don't know what else to do. Is the AVR to blame? I don't think I should have to turn off all of the audyssey stuff and turn the sub volume down to make it go away so that you can't hear it at movie listening levels.

natetg57
04-11-2014, 05:49 PM
I had a chance to mess with it more. Turning off Audyssey does not make it go away. It diminishes it somewhat though. TUrning the trim levels on the sub down from -.5 also diminishes it. The Volume on the subs themselves are set to about 2 and 3 oclock on each sub. Im able to 'pause' previews and get it to make the noise. At reference levels, you can hear this white noise sound EASILY from 15' away. I guess its normal. I have moved wires and played with settings. I can't get it to go away. No other speakers make the noise. Even at the beginning of the movie, when it kicks in, there is also a hum that is audible. I don't know. Im not happy about it because its audible and Im not sure it should be but I don't know what else to do. Is the AVR to blame? I don't think I should have to turn off all of the audyssey stuff and turn the sub volume down to make it go away so that you can't hear it at movie listening levels.

Can you try one sub at a time? It doesn't seem likely that both subs are defective.

brazosdog02
04-11-2014, 06:48 PM
I tried one sub at a time. While it was doing it, I also unplugged every electrical device from the power strip. ALL of my AV equipment is on the same power strip on a dedicated outlet. I did not unplug every single speaker wire from the back of the AVR.

With the volume set to moderate level and the SUB volume turned to max, the white noise seems to have some sort of 'hum' component. Its pretty faint. Teh white noise is pretty faint. Maybe Im just overly sensitive to it. Rythmik says they have had no issues, but I find it hard to believe the sub is totally silent at full volume levels.

I don't know and I have no way of having anyone test this subs for the same hissing noise. Since both are doing it, I do NOT think it is the sub. I think the sub is reproducing what it is getting but I don't know how to verify that a 1000 dollar AVR that is brand new has gone bad in 3 months either.

Is that even possible? IM at a loss. If you turn the subs to the side, the noise is not quite audible from the listening position, but they don't work as well that way. I guess its totally normal. Im at a loss. I guess I expect total silence from it aside from whats on the soundtrack but maybe thats not realistic.

ANything else to try before contacting Denon? IS it realistic to set the sub volume to full and the AVR to reference level and expect absolute silence aside from the soundtrack? I mean really? NO ONE has ever experienced this noise from an LV12? Its not loud, but it is noticable from LP if you have already noticed it.

natetg57
04-11-2014, 06:56 PM
Do you mean the volume knob on the back of the sub is turned all of the way up? I've never thought that was recommended. Try the sub level lower and possibly turning up the sub channel level on the receiver

brazosdog02
04-11-2014, 07:05 PM
Its not reccomended. I dont USE it like that, I just have the system paused at a particular point so there is silence aside from that noise and use the volume knob to turn it up enough to hear so I can run around and start unplugging things. But either way, is it normal to expect dead silence when the knob is set to 3 oclock and the listening level is loud but not quite reference? SHould it be silent at the sub it self or just not be audible from the LP?

natetg57
04-11-2014, 07:16 PM
Thanks for the clarification. I don't know. It sounds like me with my plasma. I can hear the buzz when everything else is off. Apparently it's normal though.
Does the sub still make the same sound with the RCA cable to the sub unplugged? Hopefully Dave or someone who owns this sub can tell you if this is normal.

RicardoJoa
04-13-2014, 04:06 PM
You shouldnt hear any unusual sound at LP. I just cant imagine hearing a hum at LP specialy while playing music or watching movie.
If you hear noise (hum)when your sub vol knob is turned up, turn it down till the noise is lower and adjust at AVR.
As with your wind noise, i think you should isolate whether that has to do while playing music or watching movie. Do you hear that wind noise with everything disconnected except power? With a RCA in? With music Playing?

brazosdog02
04-14-2014, 06:14 AM
IM still messing with it. I listened yesterday and at the LP with a good volume, its not discernible unless you really know what you are listening for. Its really hard to isolate because there is a very strict set of parameters to make it happen including volume. It has to be getting a feed from LFE. RCA Cable cannot be unplugged. It cannot be 'paused' or 'muted' or it won't make the noise. It might be perfectly normal....or rather, acceptable. Im going to try one more thing that involvs unplugging ALL audio cables from the back and all HDMI cables aside from the one source I happen to be using. If that doesn't solve it, Ill try killing the breaker to every light in that room to remove the possiblity of dimmers being an issue. The system is on its own circuit so thats an easy thing to test. There is a noticeable hum in the beggining of "Frozen" but its when the singing first starts and I think it goes away. I'm almost 100% positive its in the soundtrack somehow since its starts literally a second or two before the rest of the audio. Its like when the audio track goes 'live'. Very odd. Im probably being way too anal.

RicardoJoa
04-14-2014, 06:51 AM
IM still messing with it. I listened yesterday and at the LP with a good volume, its not discernible unless you really know what you are listening for. Its really hard to isolate because there is a very strict set of parameters to make it happen including volume. It has to be getting a feed from LFE. RCA Cable cannot be unplugged. It cannot be 'paused' or 'muted' or it won't make the noise. It might be perfectly normal....or rather, acceptable. Im going to try one more thing that involvs unplugging ALL audio cables from the back and all HDMI cables aside from the one source I happen to be using. If that doesn't solve it, Ill try killing the breaker to every light in that room to remove the possiblity of dimmers being an issue. The system is on its own circuit so thats an easy thing to test. There is a noticeable hum in the beggining of "Frozen" but its when the singing first starts and I think it goes away. I'm almost 100% positive its in the soundtrack somehow since its starts literally a second or two before the rest of the audio. Its like when the audio track goes 'live'. Very odd. Im probably being way too anal.

Ok, if you cant reproduce that while having cable off, paused or mute, then at least it sounds like it only happends when it is playing and not due to cable or electrical.

It sounds like the sound your are hearing is from the LFE.
I remember one time i was using my headphone and i adjusted the bass which in my avr was 50hz because the headphone had weakbass. The next day, when i switched it back to speaker without turning down the bass, i noticed the sound was odd and it seemed like a hum, but slighly different. I then realise that the bass was set 6 db higher. So the extra bass had caused that unusual noise. It may not necessarly be the system, but the room it self. I think it might even be flutter echo at those low frequencies.

brazosdog02
04-14-2014, 06:53 AM
Im running my Audyssey hotter than it wants, and you are the second person to mention LFE noise. So...I could be hearing something normal or just an artifact of my settings. You have to remembe that I have never ever ever had a 'system' like this, so im not well versed in normal.

RicardoJoa
04-14-2014, 06:58 AM
Also, if you need to have LFE turn up in order to feel the bass, make sure your sub is not having phase issue with the front. If sub is out of phase it will sound like a week sub, and you may think you need to turn it, but the truth lies on the phase.

brazosdog02
04-14-2014, 07:07 AM
I dont follow. My subs are both in the front. One on each side. Can they still have phase issues there? Does it really matter as long as both subs are set to the same phase?

RicardoJoa
04-14-2014, 07:15 AM
Of course. The best it to play with your speaker Distance. Different crossover requires different distance. Make sure you dont have a null at your listening position. You can tried this by palaying with the subs only and walk around the room to see if you will hear a stronger bass at other areas.
The best is to measure it.

brazosdog02
04-14-2014, 07:22 AM
I see. Yeah, ive done that. Im still testing that out too but thats a separate issue.

Blutarsky
04-14-2014, 08:54 AM
Maybe try a different receiver, one sub at a time. Different cables too?

curtis
04-14-2014, 09:09 AM
FWIW, I had a sub noise issue some years ago. I would get the noise when playing music, but whenever the TV was on, the noise would go away. So the noise was never present when watching anything.

It ended up being the standby circuit on the TV. If the TV was on, off, or unplugged....no noise. When in standby, I got the noise no matter what the source.