Hello Hello

I have an Onkyo HTS 770. It is has Dolby Pro Logic IIx and DTS ES. However, when I play the THX audio tests in the menu on Starwars Episode 2 and Finding Nemo, the back surround speakers (LS, RS, BS) do not play as they show up on the screen.

I have read that this happens because with Dolby Prologic the back surround speakers are mono or because the Onkyo receiver is not THX certified. Does the receiver still separate the speakers during the movie even though it does not match with the audio test? Is there a way to "go around" this? Can I use another decoder on my back surround speaker to turn it into two speakers to make it sound like a 7.1?


I would appreciate it if somebody tells me what is happening. Thanks

The speakers are set up correctly it simply plays one tone for all of the back speakers instead of playing an individual tone for each speaker as they show up on screen.

First, DTS-ES is not 7.1, so don't expect it to be. The rear speakers will have the same signal. DPL IIx is 7.1, so those should sound different.

Next, the THX tests are not great. I'd recommend a test disc instead, they are usually under $20. Sound & Vision by Avia or Digital Video Essentials are the names.

Lastly, even the discs aren't great at dealing with 6.1 or 7.1 setups. You may have to use the test tones from the receiver. Or you could swap wires on the receiver to plug the Rear into the Side surround slots just for calibration.

Spiky thanks for the help.

I have another question. I want to have 7.1 surround sound.

My receiver only has six out puts. FR, FC, FL, SR, SB, SL. Plus the subwofer. I want to be able to split the back speaker into SLB & SLR without changing my receiver. Can that be done? Is there something out there that I can buy? A chip? Thanks.

Doubt it. Onkyo's top of the line receiver has upgrade options, but not anything else. You would have to add more equipment, perhaps a stereo amp to split that mono signal into 2 channels. There really isn't too much need for it, though. It will still be a mono signal, just with 2 speakers.

I see I see. Thanks again Spiky.