Digital Audio Out Just Buzzes ("Motorboat")

[mbratch]

Hello --

I have what I'm sure will end up being something stupid but I just can't get past it.

My new Sanyo DP42D23 HDTV has an RCA jack labeled "Digital Audio Out". My sound bar only has L and R analog RCA inputs. I figured I'd just have to get an adapter to use the sound bar.

I tried four different adapters. All of them gave the same results: the only output I heard was a buzzing/motorboating kind of a noise, continuously from the sound bar. I couldn't find much online about such a noise except one post about changing the output format to PCM. But my HDTV doesn't have any settings pertaining to the format of the digital audio output. The manual for the HDTV just says, "Hookup a multichannel receiver with the use of a phonotype
digital audio cable." That's it. Nothing else. I called Sanyo and they finally said their TV isn't compatible with any adapters so I needed to go direct to a sound bar or home theater system that supports "digital audio input".

So I bought a sound bar that had digital audio input. That gave the same result. I was just about to declare the Sanyo defective when I decided to try my other, smaller TV (It's a Sylvania 32-inch HDTV with a "digital audio out" connector. That had the identical symptom: no sound but a nasty, buzzy, "motorboating" kind of sound.

What am I not getting? Are there different formats of digital audio output? How do I make this work?

Thanks.

 

[MongoSmash]

Are you using just a standard composite rca cable or do you have a 'Coaxial Digital Audio' cable?

 

[getochkn]

just hookup the tv with rca jacks. with a 2 speaker soundbar not a big reason to go digital 5.1 anyways as you won't get 5.1 from 2 speakers.

 

[MongoSmash]

just hookup the tv with rca jacks. with a 2 speaker soundbar not a big reason to go digital 5.1 anyways as you won't get 5.1 from 2 speakers.

That TV doesn't have standard RCA audio out jacks. Its only has the Digital audio out, according to the spec sheet. That means he has to use a Coaxial Digital Audio cable, not standard RCA cables.

 

[mironso]

Yeap, like MongoSmash said, he need to use this type of connection: http/www.p4c.philips.com/cgi-bin/cpindex.pl?ctn=HTS3306/F7&dct=QAC&faqview=1&refdisplay=QAC_89985&refnr=0089985&scy=US&slg=AEN
Just example.

 

[mbratch]

MongoSmash is right: this HDTV has no analog outputs. Just a single digital output. I am using a high-end audio cable that I've used before for S/PDIF recording. Is that adequate or correct? I bought the cable quite some time ago. I don't know if it was labeled "coaxial digital audio".

 

[getochkn]

try a different cable. even some RCA cables work good, just depends on the devices and the cable and how they play together.

 

[mbratch]

try a different cable. even some RCA cables work good, just depends on the devices and the cable and how they play together.

I reckon I can buy another cable that's properly labeled "digital coaxial audio". I had tried my S/PDIF cable and a standard RCA audio cable and both just made that sharp "fluttering" sound. I'll need to pick up another converter. I had sent the one back to amazon thinking that for some reason it wasn't compatible. Would an inexpensive convert such as this one be appropriate: http/www.amazon.com/gp/product/B005DIRI6I/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1 ?

 

[mbratch]

Yeap, like MongoSmash said, he need to use this type of connection: http/www.p4c.philips.com/cgi-bin/cpindex.pl?ctn=HTS3306/F7&dct=QAC&faqview=1&refdisplay=QAC_89985&refnr=0089985&scy=US&slg=AEN
Just example.

I know the difference between all the connectors, and I know which ones are supposed to connect to which ones. It's simply not working and just making a noise.

 

[getochkn]

Taken from the one you linked:

This audio converter (Sold by Acepurchase Inc - Fulfilled by Amazon) may work fine for some but, for many TVs, etc., this product does not seem to work if your (source) device does not support PCM/LPCM output. i.e. if your device will only output in the Dolby or other DTS formats, this converter is incapable of "decoding" these signals thus producing only white noise. It does not state these limitations in the product description where I had to, literally, learn the hard way.

After learning the differences in the newer audio formats, I found that I needed an audio decoder such as CE Compass Digital SPDIF / Coaxial to Analog L/R RCA Audio Decoder w/ 3.5mm Headphone Jack. This decoder works fine for me, but, still only outputting analog L/R signals. I knew this would be the result for either a converter or decoder and am happy for being able to use my (very good sounding) older analog stereo system with my new LCD TV.


This may your problem.

 

[mbratch]

Taken from the one you linked:

This audio converter (Sold by Acepurchase Inc - Fulfilled by Amazon) may work fine for some but, for many TVs, etc., this product does not seem to work if your (source) device does not support PCM/LPCM output. i.e. if your device will only output in the Dolby or other DTS formats, this converter is incapable of "decoding" these signals thus producing only white noise. It does not state these limitations in the product description where I had to, literally, learn the hard way.

After learning the differences in the newer audio formats, I found that I needed an audio decoder such as CE Compass Digital SPDIF / Coaxial to Analog L/R RCA Audio Decoder w/ 3.5mm Headphone Jack. This decoder works fine for me, but, still only outputting analog L/R signals. I knew this would be the result for either a converter or decoder and am happy for being able to use my (very good sounding) older analog stereo system with my new LCD TV.

This may your problem.

I think this hits the nail on the head, in that (a) I couldn't get any information out of anyone (including Sanyo support) about different forms of "digital audio output" and, specifically, what does the Sanyo HDTV output, and (b) I already did a lot of experimenting to get where I'm at now which is try two different TVs, a couple of different cables, and two different converters (the one in the link, and a $40 converter that RadioShack sells). I finally tried direct connect of my TV to the digital input of a sound bar that does support digital audio input and still go the buzzing. This just left me with not knowing whether the problem was that there were simply different digital audio formats (and none of the equipment was identifying which one it used) or wrong/bad cable or maybe both. I had bought the sound bar with digital audio input as a test to see if my problem was trying to do the conversion, but that test result was negative (I since returned that sound bar). I was just about to return the new Sanyo HDTV to the store for a refund, thinking it was defective, until I had tried my other HDTV and found it did the same thing with the "loaner" sound bar.

I wouldn't call the noise I hear in these tests white noise at all. It's a very choppy sound, several Hertz in frequency (8-ish? not sure).

So I'm back to square one: my Sanyo HDTV with a connector labeled "digital audio output" and a sound bar with RCA L/R inputs and a fair amount of uncertainty regarding whether I can make them work together. I tried the little black converter I showed in the link I posted in the above tests. But what format(s) does it support? If I knew that I could perhaps try a different converter that supports different or more formats. What throws me is that the one I linked, that has the disclaimers, says it supports S/PDIF and a variety of sample rates (I'm not sure how each end decides which rate to use), and the CE Compass also says S/PDIF. So to my feeble, mind, these would behave roughly the same way in my setup. I'm still confused why a new HDTV won't play with a new sound bar if the former has a "digital audio out" and the later a "digital audio in" and neither company can tell me that there are specific formats that their gear supports that I need to be concerned about when shopping to match them up. I read a thread somewhere in which someone described exactly the noise I experience, and their solution was to go to the audio settings in their TV and set it to PCM, which fixed their problem. But my TV doesn't have any such settings. :-/

And what if I had a fancy home theater unit with digital audio input? Would I still get a noise? I'm left wondering. I'm not wanting to buy such a system just to see whether it's true.

This seems like it shouldn't be this complicated. Or maybe I'm making it complicated. :-/

 

[getochkn]

It does seem the one the reviewer mentioned, http/www.amazon.com/CE-Compass-Digital-Coaxial-Headphone/dp/B008U23F3E might work as it's a decoder. I think thats the problem. the TV is outputing something and all the conveters you tried were just that ,convertors, not decoders. They can't make sense of it because they expect basic pcm or something and your tv is probably outputting dolby. Maybe something to try, if this aplies to you, is try a non-HD channel, if you have any. my cable service, only about 30% of the channels have an HD version and the non-HD versions don't usually output dolby audio, just basic 2 channel, only the HD channels have the 5.1 or DD logo next to them.

 

[mbratch]

It does seem the one the reviewer mentioned, http/www.amazon.com/CE-Compass-Digital-Coaxial-Headphone/dp/B008U23F3E might work as it's a decoder. I think thats the problem. the TV is outputing something and all the conveters you tried were just that ,convertors, not decoders. They can't make sense of it because they expect basic pcm or something and your tv is probably outputting dolby. Maybe something to try, if this aplies to you, is try a non-HD channel, if you have any. my cable service, only about 30% of the channels have an HD version and the non-HD versions don't usually output dolby audio, just basic 2 channel, only the HD channels have the 5.1 or DD logo next to them.

That seems to make sense. I didn't think to try a non-HD channel (we have some).
It's frustrating that this sort of information isn't spelled out in data sheets for the different devices so the unsuspecting consumer stands a vague chance of making the proper selection. I can see why the 'dumb' converter wouldn't work. But why wouldn't a sound bar with digital audio input work? This is the one I tried: http/www.radioshack.com/product/index.jsp?productId=28494046. Of course, the specs just say 'digital audio in' and nothing else. It's inexpensive so perhaps it's also just PCM.

So I'll order up one of the CE Compass devices and see what happens. I'm quite hopeful that will work. The rationale is quite logical.

**UPDATE 2/18/2014**

Received the CE Compass device today and plugged it in. Worked perfectly.

 

[getochkn]

**UPDATE 2/18/2014**

Received the CE Compass device today and plugged it in. Worked perfectly.

Good stuff. So was a convertor vs decoder issue. Sort of glad that worked, I may be facing this soon. I have a soundbar/cable/pc/tv with only SPDIF output issue. I have it working fine now but requires me switching inputs on the soundbar.