Static / Signal Noise from New Speakers Tweeters

[lespaul00]

Hello,

I'm new here and have a question about new speakers that I recently purchased. I've been searching the web for an answer, and haven't had much luck to this point.

I have brand new Polk Audio Monitor 75T speakers that I added as my Front L and Front R speakers in my 5.1 Home Theater System. My Center channel is a Polk Audio CS2. I have a Denon AVR-2112CI Receiver. My back two (surround) speakers are smaller Polk Audio speakers from a previous 5.1 packaged system I purchased from them a few years back.

I went through the Audyssey set up with the Denon receiver and it adjusts the channel level for my front 2 75T speakers higher than my center channel. I believe this is normal, ... since if I set them all the same level, the center channel sounds a bit too high. This is an image of what my 5 channel levels are set to:

Now to my issue. When I have either my TV (DirecTV connected to Denon via HDMI to transmit both Audio and Video) selected or my HTPC (HTPC HDMI out using new Intel 4000 graphics to Denon via HDMI to transmit both Audio and Video), and let's say it's in between commercials (or just sitting on my Windows desktop) .... i.e., no sound at the moment, there is a very noticeable static sound coming from the speakers (primarily the front L and R). If I adjust the Front Channels' volume up, it's more noticeable. It's like that sound you get on an FM radio station when you are in between stations searching for one (well, not quite that bad, but same sort of sound). Basically, it's something I've heard from most speakers I've owned, but for some reason these seem slightly louder, and I thought I was purchasing a quality speaker here that shouldn't have this issue.

Now, if I am watching a movie really loud, this is where it bothers me most. Because, when the movie has a quiet moment, this staticky sound is more noticeable. So, I really want to figure out what it is causing it, or at least a way to minimize it.

I can turn the Front L and R channel levels down and it's much less noticeable. But then, I just need to turn my volume up to hear. Then I can hear the static again.

I removed the front covers of the speakers and listened closely to each part of the speaker. The static sound is coming from the tweeter. However, when I do play something, I hear sound from the tweeter. I included a picture below to show where this static sound is emanating from:

For more information regarding my system, here are some more details. I hear the static sound even when my DirecTV box is turned OFF, but my receiver is set to its input. I have a picture shown below of the front of my receiver (the flash makes it look like the DirecTV is on, but it is off).

I also hear it when my HTPC is in sleep mode but the Denon is set to the HTPC input. An image of my Denon during this case is below:

Also, I have each speaker hooked up with 12 AWG speaker wire. I checked each connection and reconnected. They are tight. I have banana plugs on order to see if that helps. I also shortened one of the speaker wires to ~4 feet, and it didn't resolve the problem.

Here are some things that I can think of that may be the issue, but I'm really at a loss:

• Need better speaker wire. Perhaps the static sound is from a poor signal from the transmission through the wire? Do any of you have recommendations on very good speaker wire for these floorstanding speakers?
• Something may be set incorrectly on my Receiver. I tried my DirecTV (SD and HD channels), and various file formats on my HTPC (including DTS-MA, DTS, Dolby, MP3) and the same issue exists. I actually do not think it is related to the media at all - I think it is something with my Receiver, speaker wire, or speakers.
• My tweeters may be blown, but I don't think so. If I turn my center channel up really high, I can get that same type of staticky sound, but the good thing is, my center channel sounds good when it is set lower relative to my Fronts (which I think is normal).

Any help is appreciated. Thanks!

 

[j_garcia]

If it were speaker wire, it would only be if they were directly running parallel to power wires - and it would also be in all drivers most likely, not just the tweeter. The quality of the speaker wire itself is definitely not related to this. 12AWG also means the size of the wire is not a factor here, and since the runs are less than 40ft, it wouldn't matter if you were running 14AWG.

The second seems more likely, crosstalk on that input that the PC is using or it is simply noise coming from the PC itself and that is HIGHLY likely since PCs aren't quiet by default. Try switching it to a different input. If you get the same thing, then the receiver is likely not the issue and the PC is. DIRECTLY related to that is the fact that they are set so much higher than the center because the amplifier amplifies everything, good and bad, whether you want it or not. You didn't mention other sources like a BD or CD player. Do you have the same problem with any other sources? Just to eliminate them, I'd remove both the DTV and the PC and try each individually and see if one, the other or both of them do the same thing. Chances are good it is one of the two.

Blown tweeters are generally pretty obvious - they either sound horrible or make no sound at all, so that is less likely as well.

Try altering the placement of the main speakers and re-running Audessey. Speakers don't hiss, they only reproduce hiss. This is coming from the receiver or sources or your power lines.

 

[lespaul00]

Thanks for such a quick response!

I tried some of your suggestions. Here is a summary of the results:

1. I removed ALL HDMI cables from my receiver. This left just the speaker wires attached. I first switched through EACH input on the receiver. I could hear the sound from the speakers on just about all of the inputs during this test, except for the TV input. All inputs resulted in ANA. showing up in a box on the Denon screen. For the TV input, DIGITAL showed up in a box on the screen.

2. I tried my DirecTV alone, tried my HTPC alone, and still got the problem.

3. I grabbed a BD Player and hooked that up alone via HDMI. Got the same result.

4. So then I put it back to my original setup, and turned on my DirecTV. I started trying the different audio modes (movie, music, game, direct). When I chose the "Direct" mode button, the problem almost went away. There is still some static sound if my ear is close to the tweeter, but it's much better. If I hit the button again, it goes to "Pure Direct", which I do not know what the difference is. The static is about the same on this setting as it is on the Direct setting.

So, I think I got it to a point where it's better, and most people won't hear it. It still bugs me, because I want the static to be eliminated. Also, it did seem like it is slightly more noticeable on the HTPC than the DirecTV.

Some follow up questions:

1. Is there anything I could buy to "shield" my speaker wire better if it runs along power lines? Basically, I have a media cabinet where all of my wires run behind (in a small space, bunches close together). This includes the power cables from my DirecTV box, receiver, Logitech Revvue, HTPC, and small ethernet switch. Is there some sort of conduit I can get to run the speaker wire within to shield it?
2. Is there some sort of setting (maybe it's that Direct setting) to just preserve the raw audio from each device and not mess with it (bitstream?). I have everything set on my devices to passthrough to the receiver. But, is there a setting on the receiver to just play as is?
3. Are there any recommendations on good HDMI cables to use? Would that contribute to this issue at all?
4. My receiver is in a cabinet and gets fairly hot. Could that contribute to this issue at all?
5. For an HTPC, I was told I do not need a sound card since I have everything passthrough to my receiver, and I have a brand new CPU with Intel 4000 and a motherboard with HDMI out. However, would a dedicated sound card help the issue you mention that "PCs are never silent"?

Thanks!!!

 

[Grador]

For an HTPC, I was told I do not need a sound card since I have everything passthrough to my receiver, and I have a brand new CPU with Intel 4000 and a motherboard with HDMI out. However, would a dedicated sound card help the issue you mention that "PCs are never silent"?

A sound card would likely cause more issues, as you'd be swapping out the digital HDMI with an analog connection that is several orders of magnitude more likely to carry electric noise from the computer.

If there's noise with nothing hooked up, and it's variable with the volume setting then I think it's time to start looking at swapping out that receiver.

 

[lespaul00]

If there's noise with nothing hooked up, and it's variable with the volume setting then I think it's time to start looking at swapping out that receiver.

Oh boy...it's not even 1.5 years old! Is it possible that excessive heat in the media cabinet could contribute to poor receiver performance? Should I check into my receiver warranty?

 

[TLS Guy]

Oh boy...it's not even 1.5 years old! Is it possible that excessive heat in the media cabinet could contribute to poor receiver performance? Should I check into my receiver warranty?

Yes. the receiver is the source of the problem.

However I note that Audessy has set the gain high. Actually I think Audyssey has made a mess of things. I think that is is very unusual for the mains to have to be set to +8db.

I would go to the speaker set up and set the mains to 0db. Set the center to -8db. Set the surrounds to -4.5 db.

I think Audyssey has set the gain too high and this has degraded the signal to noise ratio. The tip off is that is that in Direct mode it largely resolves.

I think there is a good chance that Audyssey has also got the relative levels wrong. I would check the levels with an spl meter.

The problem is not a caused by the speakers or the wire.

If you still hear hiss at your seated position with the mains set to zero db then your receiver needs replacement.