Axiom Home Page Forums General Discussion Home Theater Cable television sound quality...how sibilant?

I watch a lot of cable television through my local cable provider (Shaw). I subscribe to a fairly comprehensive cable package so I get both SD and HD channels using various audio formats - some DD 5.1 and some are played in Dolby PLx through my AV receiver.

When I first received my HT system (M60, VP150, QS8, EP500), I noticed that cable sound quality was fairly sibilant through my center channel. Lots of emphasis on the s's and f's. I got used to it and didn't notice it much after a couple of months.

Recently, however, I've been playing with my system and have been listening to a variety of different audio sources. Since then, I've come to notice the sibilance again and it is beginning to become fatiguing to watch cable television. While different channels have differing levels of sibilance, they all seem to possess it.

Now I'm wondering if something is wrong with my VP150 center channel that is causing the excessive sibilance. Please help!

Is cable television expected to have excess sibilance? Even HD 5.1 broadcasts seem sibilant. What do others on this forum experience when watching cable television? How can I confirm that my VP150 isn't overly sibilant/bright?

Any help/advice would be appreciated. BTW, my cable provider is Shaw Cable (in Calgary, Alberta, Canada). I mostly watch the major US networks in HD/5.1 along with a smattering of SD channels.

Thanks in advance!

Bryan

Just run a good signal (BR, DVD, etc) through the system at the same volume. If the anomaly appears from clean sources like these, you need to move down the chain and check the AVR, and the speakers. If not, it is just a cable issue. While on cable, you can also change the wiring so your center sound (in DD) is routed to one of your mains. If only the right speaker (for ex.) now has the sound (and you are using a clean source) you have a problem with the center channel of your amp. If the anomaly stays in the center channel even when the center is using the signal for the Right channel, you have a problem with the center speaker and should call Axiom.

I don't know your cable company, but cable loves to compress information as much as possible. The more compression they can get away with, the more channels they can shove into their allotted bandwidth. Locally, they shove well over 300 channels down the coax line, and I know other places have even more. My guess is that your cable company is just compressing the audio track so it sounds like a bad MP3 records, with harsh frequency response in the highly compressed zones. Here the sound is fine, but we get tiling and other visual anomalies from compressed cable.

Also, try watching in stereo so the center sound is spread to the main speakers. If it is the cable, you should get the same anomalies in the mains - unless the issue with DD decoding, at which point I'm not sure you could trust a test in stereo. Others will join and get you through this. Do you have access to satellite TV, perhaps that would be your best and most cost effective solution? Best of luck; with a system like that (assuming your amp is of equal quality) you should not have to deal with fatigue or make severe tone changes to enjoy it.

Unfortunately, even with today's technology, I have found that there is still channel to channel differences not only in sound but volume as well. It is at its worst with standard definition programming. Also even with HD channels(In my case Rogers is the service provider) I have even found differences in sound and volume from the same network and the same programming. I have all the US networks from both Buffalo AND Seattle. I was watching the game on the weekend and was flipping back and forth between the CBS stations between the two cities and the channel from Buffalo was considerably louder especially in the center channel even though, in both cases, they were broadcasting the same thing. Rogers insists its how they are getting the signal from the origin and it is not them. I think it is probably just a minor change in how the signal is being transmitted down the line and since sibilance is caused by frequencies generally in the 8-10kz range, perhaps a slight tweak to the treble control on your AVR will solve the problem. I doubt it is your speaker.

zimm, casey01 - thanks for your replies.

zimm - I had started doing some of the diagnostics you had suggested (i.e. re-wiring center channel to on of the mains, playing cable in stereo, etc.) but I just had a new baby (well, my wife did while I watched :)), so I haven't had much time. I'll continue with your suggestions this week when I get a chance.

casey01 - I agree, I get the same differences is SQ and volume from channel to channel. The worst is HD though - the program's volume is much quieter than the commercials. I have to continually throttle the volume on my receiver during commercials (quite annoying).

Does anyone have experience with Shaw cable in the Calgary (and area) region? Do they notice the sibilance with Shaw on their center channel/setup?

Hi icehawk21,

As Zimm suggested, try switching your AV receiver to stereo and listening to the same sources to see if the sibilance remains. That's an excellent test, and there shouldn't be any variations in the decoding of Dolby Digital. The algorithms for this codec have been around for years.

Other factors that come into play are the frequent use by announcers of microphones that have intentional "presence peaks" built into the frequency response of the mike, for added intelligibility of speech reproduced over the usually lousy internal speakers of many TV displays. If programs with those mikes are played over high-fidelity wide-bandwidth speakers like Axioms, you'll hear the sibilant presence peak in the speech range.

Regards,
Alan

Yes, obviously the "presence peaks" are the next logical issue. I knew that...but I thought it was too obvious to suggest...right.