# Need Help - Very Loud Popping Sound



## sga2

So... I was watching Bourne Legacy on BluRay last night for the first time. When the disc/BDP transitioned from the Main Menu to begin the movie, there was a very loud "CRACK" then the sound went dead but the picture continued without missing a beat. My receiver's safeties must have tripped because the sound came back to normal after I cycled the received off then back on. It seemed to come from all channels though it was very sudden and I am not sure whether that is the case. Anyway, it made my heart jump (not so much being startled from the sound, but worried about any damage to my gear) and I was wondering if anyone has any ideas what caused this. 

For reference, you can see my gear here.

I've checked all of the speaker connections and they seem to be fine. We also had no problems watching the rest of the movie. When it was over, I even replayed (at lower volume) the beginning of the disc - removed disc from BDP, reinserted, played through the previews, and then started the movie from the Main Menu - without incident.

It is possible that there was a spike in the power line, but I doubt this as (a) there was no lightning activity anywhere near me, (b) I have two levels of surge protection (whole home protection at power/phone/CATV and power strips at my equipment), and (c) I saw no other signs (projector flicker) that this was in the power line though I cannot be certain. Also, for what it is worth, I heard a similar "crack" (though I had the volume much lower) just a few minutes before while this disc was transitioning between previews.

It may be worth noting that I've not made any changes or moved any of my gear in quite awhile so aside from the movie itself, there is nothing new going on in my setup.

In the past few years - since I completed the home theater - I've heard faint pops betweeen previews or when switching from disc menu to movie before but those have only been barely audible even when the system is turned near reference (we usually settle around -15 to -10dB). It's never sounded like this or been this loud before. I'm at a loss, but am going to be nervous that I'm going to fry something until I figure this out.

Any ideas? Thanks for any input.

Regards,
sga2


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## ALMFamily

I have not read anything that helps, but I do periodically get a loud popping noise out of my Sherwood 972 when video formats switch - like going from a non-HS channel to an HD channel on cable. Is it possible this occured?


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## Gregr

I am not an expert on this problem but because grounding issues are so common I have been keeping an open mind for ideas when reading. Well I am reading a source paper (I would call it) from Elliot Sound Products written by Bill Whitlock.

In this article titled *"Design of High-Performance Balanced Audio Interfaces", *Bill states popping, crackling and hum are grounding issues unless these sounds are in the program or are unaccounted for otherwise.

In any case if this is a grounding issue it is is because of unequal grounding voltages.An example is when a system is fully balance except for the unbalanced speaker wire to the sub. If your system is an unbalanced (RCA interconnects) system speakers must be connected with 2 wire speaker cable. If interconnects are balanced then speaker cables must be a 3-4 wire speakon or 1/4"TRS connection. In other words grounding voltages needs to be symmetrical and consistent for each piece of gear in the system . If 1 piece of gear is lacking a proper ground something as simple as the refrigerator start-up can spike or then brown out the voltage to the audio system enough to POP or crackle and maybe even trip the safety breaker in the AVR and not pop the system breaker.

I hope that helps??


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## sga2

ALMFamily said:


> I have not read anything that helps, but I do periodically get a loud popping noise out of my Sherwood 972 when video formats switch - like going from a non-HS channel to an HD channel on cable. Is it possible this occured?


This is what I assumed was happening, but the sound was so loud and offensive that I think/hope there is more to it. I hate to think this could happen at any time.

Thanks,
sga2


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## tonyvdb

Just out of curiosity have you ever updated the firmware on your 3007? There was one available at the end of 2010 made available. This "Pop" sound almost seems like the the DTS master audio "bomb" that was causing issues in some receivers. Was the Pop out of the speakers or out of the receiver its self?


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## sga2

tonyvdb said:


> Just out of curiosity have you ever updated the firmware on your 3007? There was one available at the end of 2010 made available. This "Pop" sound almost seems like the the DTS master audio "bomb" that was causing issues in some receivers. Was the Pop out of the speakers or out of the receiver its self?


I've upgraded firmware twice I think. I check every few months and no firmware has been available for at least a year.

Regards,
sga2


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## Jazz555

You are right and thanx for sharing it.


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## tba

sqa2, if your cable TV decoder is also connected (probably via HDMI) to your AVR, disconnect it. Connect it via HDMI directly to your projector (TV) and via optical cable to your AVR. That should avoid the cable voltage pass. Try again the BD.
Regards.


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## sga2

tonyvdb said:


> Just out of curiosity have you ever updated the firmware on your 3007? There was one available at the end of 2010 made available. This "Pop" sound almost seems like the the DTS master audio "bomb" that was causing issues in some receivers. Was the Pop out of the speakers or out of the receiver its self?


It was from the speakers. Apparently it was the HDMI board (replaced by Onkyo) singing its death knell.

Regards,
sga2


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## sga2

tba said:


> sqa2, if your cable TV decoder is also connected (probably via HDMI) to your AVR, disconnect it. Connect it via HDMI directly to your projector (TV) and via optical cable to your AVR. That should avoid the cable voltage pass. Try again the BD.
> Regards.


I do not have a TV/cable/sat decoder box in the home theater. We bring one down for special occasions (e.g., Super Bowl) about once a year.

Regards,
sga2


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## Gregr

I believe TBA (to be announced?) is on track...

FYI - if the distance from your projector to the ground rod or the breaker box (if all power is sourced from a single breaker box) is different than the distance from your AVR and/or source components to ground. The differential lengths in circuits can become problematic especially when different length circuits of the projector or TV are connected via HDMI (copper digital) back to the AVR or source component. Replace your HDMI cable from the AVR or any source component to the projector with optical and your snapping popping or hum will end, unless there is a secondary issue of similar nature. 

Regards


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## mcascio

What source are you using for your BluRay player?

It sounds to me like the DTS Master Audio bomb as well. Certain combinations of bluray players and receivers seemed to have caused this. It sounds like gun shots and extremely loud. They tend to occur at the same place too. Try setting your playback on the bluray to 5.1 or something and see if the popping goes away.

I solved my problem by going from an HTPC for bluray playback to a Dune player.


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## Gregr

Hello All,

This is such a common problem, especially with Home Theaters. With the video system power 20' to 50' away is the audio system power there is potential for ground loop issues; If/when you use HDMI to run video to a projector or any copper connector to or from the AVR and projector. 

Any different length power feed to system components can be the source of hum, pop, crackle, etc etc etc
Here are several links to several solutions for potential problem areas e.g. cable box, interconnects, etc etc. 

Enjoy in good health

http://www.edcorusa.com/p/220/wsm6400




http://www.crutchfield.com/S-eJol3IGPYSp/p_127SNI1/PAC-SNI-1.html?tp=2653&id=detailed_info#Tab




http://www.sweetwater.com/store/det...g&matchtype=&gclid=CNXhorWqirgCFapDMgodxHkACQ
http://www.amazon.com/electronics/dp/B0070Q6URO




I believe there is one other but have not located it yet - a transformer for circuit breaker box specifically for ground loop issues.


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