Axiom Home Page Forums General Discussion Home Theater Receiver Problem

As you may have noticed from another thread, I have been in the receiver market for quite a while and have not been able to make up my mind. I had planned on waiting until the "spirit" moved me because I thought that my old receiver was basically doing just fine.

Well, I have noticed a "problem" that is really starting to bug the wife and I.

I have Comcast cable connected directly to my new Sony HDTV. It is my understanding that the Sony's tuner will accept and decode multichannel DD audio from the cable signal. Even though the Sony has an optical (audio) output for multichannel DD, I am just using the Right Left outputs to my old Kenwood receiver. Why? The old Kenwood only has one optical input and I am using that for my OPPO DVD player.

Now for the problem. The audio on the HDTV cable signals is sometimes overwhelmed by the surround sound/ noise/ audio. For example, on a football broadcast, it is sometimes difficult to hear the announcers because of the crowd noise. The same thing sometimes happens on "24," "E-Ring," and other HD shows. It is like the center channel is not driven hard enough.

I am using a 5.1 system and all channels were calibrated with a Radio Shack Sound meter.

I am beginning to wonder if the old Kenwood is being confused by the TVs audio output? I have tried the Kenwood with all of its digital modes. Prologic seems to be the best, but still is not good.

I have thought about adding gain to the center channel, but, then it wouldn't sound right when I watched a SD channel or used the DVD player.

Have any of you experienced this effect? If so, what did you do about it?

Maybe I just need to flip a coin and get a new receiver????

Hello RP

Some receivers require that you calibrate the speakers for each source. In other words, just because you have calibrated the receiver for DVD doesn't mean it will 'take' for your HD cable box source.

Just a thought. I always found Sony receivers have a decent processing section but weak amps. Maybe you should check out the manual again.

G'luck

Turn your center channel up and surrounds down. Pretty simple.

Recall, I am not using a cable box. The cable is fed directly into the TVs tuner. I only "hear" this problem on the HD channels, not SD channels.

The old Kenwood does not vary the calibration from source to source.

I'm confused. So your Kenwood reciever is only getting left/right signal from the Sony TV which is decoding DD from cable? So when you're watching TV, you should only be getting sound from the right and left speakers, no? If you're getting them from everything, the receiver must be doing some sort of surround processing, such as Dolby Pro Logic. It can't be doing Dolby Digital, because there's no digital connection from the cable to the receiver, right?

Yes, basically you have it correct. The receiver is just getting Right and Left from the TV. To get the surround sound, the old Kenwood is doing processing.

What I suspect is happening on the HD channels is that the audio is multichannel audio. The TV is "processing" it and then producing Right and Left for the outputs. Then, the receiver is taking the Right and Left and "processing" it again for surround. In the double processing, something is getting confused.

I really have no idea what algorithms are used.

But, in any case, it only does it on the HD channels.

As an aside, you mentioned "24". If that was in reference to this past week's season-opening episodes, they were mixed pretty poorly. My wife and I both noticed that the first night was particularly bass heavy, and made the dialog extremely difficult to hear/comprehend. And we weren't using the HT set-up. We were using our Sony HDTV's built-in speakers.

Sorry that doesn't really help your issue, but should give you some peace of mind that the "24" issue was not your system!

Take care,
Rich

Yes, that was in reference to the Sunday and Monday night "24" shows. I really enjoyed them.

But, I was watching "Idol" this evening on FOX HD and the same thing was happening. I went to the FOX SD channel and the problem went away.

I guess that no one else on the board is seeing this effect.

My situation is similar to yours. I suspect source signals.

My HD which is OTA changes by channel and program. Some have no center, some too much bass. The Denon shows 5.1 for true HD channels and stereo for SD digital.

My basic cable (no box) shows no signal type on the Denon, but is processed to 5.1 by the Denon.

Both basic and OTA come from the same digital out on the SXRD.

For the programs with no center, the mains were phantoming or I change to PL music to change the soundstage. Too much bass means changing the sub volume. (I wish Axiom had a sub volume remote.)

I'd say that you are absolutely right. Might be worth trying to switch the optical input to the TV just to test.


Time for a new receiver!

Thanks bug. Yes, I have noticed the booming bass also. The old Kenwood has a feature on the remote where I can turn the bass down.

So, what you are saying, a "new" receiver will not cure this since it is a source problem.

One other thing that I am going to try is use just the 2 channel stereo mode.

The reciever answer is no and maybe.

No, it won't fix the source problem.

Maybe the Kenwwod has the ability to adjust DSPs.

The SXRD can change picture modes. You can adjust "Vivid, Standard, and Pro" to suit you. I change this mode depending on the program. I reduce the contrast on some HD programs where everybody is in a shadow.
I think my Denon can adjust different DSP modes. You can pick a DSP and adjust it for a particular channel or program. When that program airs, pick the DSP to match just like changing from "standard" to "pro". I've never done this, but maybe someone else with a Denon can clarify.

Rat,

You should be letting the Kenwood do the Dolby Digital decoding, not the Sony. Doesn't the Comcast box have an optical or coaxial digital output you can connect directly to the Kenwood? From what I understand, your Kenwood is doing analog ProLogic surround decoding from a left/right analog inputs from your TV, which in this day and age is pretty awful by comparison to clean Dolby Digital processed through a good A/V receiver decoder.

In any future upgrade, avoid Kenwood.

Comments on weird 5.1 broadcast audio mixes are right on. But the whole point of individual level controls for each channel is to let you adjust the center (or surround) levels for intelligibility. Some sportscasts I've watched are ludicrous. They mix the crowd noises very loud in the surrounds and the announcers so low you can't hear them. So lower the surround levels and raise the center! Don't get all locked into "calibration".

And yes, "24" was very bass heavy this week. So I turned down the EP500 sub level on my receiver by a few dB.

Regards,

But since he's not putting anything but already decoded left/right signals to the receiver, of course it's going to sound weird when processing is applied to it! A new receiver would fix this, not because of the ability to separately adjust levels, but because he would have more than one digital input.

He doesn't have a "box". His rf cable runs to his tv. (My too.)

The SXRD has a coax digital out or L/R out that carries the signal to the receiver. Since he doesn't have enough digital inputs, he is using the L/R connection.

Ken,

Of course, more digital inputs on a new receiver is the answer. But even with the old ProLogic processing, he should be able to adjust the channel levels for better balance.

On your 1090, under the video 2 (optical) connection, there are two more connections: video 3 and 4. Next to one is "AC-3 DIGITAL IN". Your Oppo has a coax digital out. Have you tried running a coax from the Oppo to one of the receiver inputs and then using the optical out on the tv to the Kenwood?

Both connections are digital, so it shouldn't make any difference which you use.

In reply to:

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The SXRD has a coax digital out

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This should read Optical digital out...........sorry!

But is the ProLogic processing going to get anything useful or appropriate out of an already decoded right and left signal of what is previously a multichannel stream?

kcarlile,

That's what I was thinking about as I wrote my previous post. Maybe not. Since the Sony is decoding the discrete left, center, right and two surrounds plus an LFE, and Rat is feeding only the left and right analog to the Kenwood, then there may be only residual leakage of signal for the center and surrounds in the L/R signal. Just a theory.

Regards,

In my experience, when you have a plain stereo signal, activating Pro Logic on a receiver results in a poor sound field.

Sounds like a good theory to me.

Doesn't DPL (I) require some sort of built in encoding in the L/R signal the decoder is fed? If it doesn't get that encoding, wouldn't it just mess up the sound? I don't know; I've never used a DPL I receiver; I know that DPLII will take any source and "decode" it.

Ken,

Yes, old DPL and Dolby Surround is a matrix-based system, with the additional channels flipped in phase and piggybacked on the L and R signals. The center was just L + R and surround was L - R. The separation between channels was only about 3 to 6 dB, enough to make it sort of work. But for music it was hopeless. It seemed to collapse everything into the center channel.

DPLII still looks for out-of-phase material in an L/R stereo signal but operating in the digital domain, it's much cleaner and the separation is way better.

It seems to me the Dolby Digital decoder in the Sony set should do a quasi mix-down of the the 5.1 signals suitable for the L and R analog outputs, in which case there should be information there that the Kenwood DPL would extract. . .

Alan

Thanks Alan and Others!!!!

I think that you confirmed my theory about what was happening. I don't think that there is much that I can do about it.

The Comcast cable goes directly into the Sony without using a cable box or cable card. I posted on another thread about this and I haven't figured out why it works. The channels are not listed on the Comcast website and when I called their tech support, they knew nothing about it. These channels with the .xx (like 92.10) must be commonly known because my son told me to look for them in the setup. He had read about them on some website.

Kenwood is not in the running for a new receiver, Onkyo, maybe Yahama or Denon. I really need to get off my butt and make a decision. Receiver will most probably drive a seperate amp.

Bug, I may try using another receiver input for the OPPO DVD. I had been thinking about that but the "spirit" just hasn't moved me. Probably won't for a while because grandson #2 arrived last night.

Once again, thanks for all of the excellent input.

Alan,

I can only see the Sony doing that if Rat had set it up so that it knew that it only had L&R outputs. As far as it knows (unless it does active sensing on the outputs), it's got all 6 channels, so it doesn't need to mix down.

Of course, it's all academic at this point...

Alan: I really don't know what audio processing the Sony does. I have read the instruction manual a couple of times and it isn't clear that it does any processing. Now that I have had the TV for a while, I should probably read the manual again and look for things like this.

Thanks once again.

There's not much in there about what it does. It has to decode in order to have the optical output.