Optical cables, worth it or not?

[da5176]

Hey guys, looking for some input. My new receiver, an Onkyo TX-SR702, has optical inputs and outputs. Would it be worth it to get some optical cables for it? Would it improve the sound quality that much? Anybody out there use them?

 

[MDS]

Optical or coaxial digital connections are required if you want to listen to digital formats like Dolby Digital or DTS, so yes you should get an optical cable.

 

[spider_duggan]

I don't mean to hijack this thread, but I have a good question that may help with the solution.

I really like two channel audio. If I trust that my cd carrier has a better DAC then my reciever, then should I use R-L analog cables so that my cd carrier does the conversion?

I mean, if I don't want DD or DTS, is there an advantage to analog cables?

thanks

 

[MDS]

I wouldn't call it an advantage so much as a preference. If you feel that the cd player has the better dacs then go ahead and use analog cables. I would suggest trying it both ways and see if you can really discern a difference.

 

[tbewick]

I've found optical cables sound better than analog cables because there is less background noise. I've heard that toslink cables can have some problems with phase distortion but I've used them and not had any trouble.

Hello spider_duggan,

There are technical differences between DAC designs, but whether this has much bearing on sound quality is open to question. I'm sure I've read posts here that say that double blind tests show that CD players are indistinguishable from one another. The main reason for having a DAC in an amplifier is to sort out the Dolby Digital/DTS signals, use the subwoofer (this is done using a digital filter), and use DSP effects without having to do an unnecessary analog to digital conversion step, i.e. CD player does a digital to analog conversion, then the amplifier has to do an analog to digital conversion on this signal to filter it (say, if using a subwoofer) then it has to do a digital to analog conversion to output the sound. In most instances the analog to digital conversion step is more degrading to the signal than doing an digital to analog conversion.

You could say that the amplifier has to be good at interpreting digital signals sent through a toslink/electrical digital cable and the cable itself must be good in not distorting the signal (group delay etc.), but I doubt whether these have much bearing on sound quality.

 

[spider_duggan]

Thanks for the info guys,

I'm currently using a coaxial digital cable, but have a good set of analog cables that I might give to a friend who just purcahsed a Rega P3 record player and a set of B&W speakers. He setting up a system that will only be for LP's and I think the reciever/amp that he's looking at will only have analog connections, since it's for LP only.

On another note, I'm glad to hear that the most important difference between DAC quality is, 'can you hear a difference.' What else matters?

cheers

 

[BMXTRIX]

Hey guys, looking for some input. My new receiver, an Onkyo TX-SR702, has optical inputs and outputs. Would it be worth it to get some optical cables for it? Would it improve the sound quality that much? Anybody out there use them?

Digital is the real requirement for surround audio at the highest level. Either digital optical, or digital coaxial. Either one is fine - neither is notably better overall.

As said though, if you are a serious 2-channel listener, and you have a killer CD/DVD player, that has really good digital to analog converters (DACs), then you may see a benefit by using analog interconnects between the player and your receiver.

My guess is, that you probably have fairly normal equipment, so you will benefit from digital.

But, if you are currently hooked up via digital coaxial, then switching to digital optical will not result in a performance increase.

 

[markw]

As opposed to what?

Would it be worth it to get some optical cables for it? Would it improve the sound quality that much? Anybody out there use them?

An analog feed? Yes, a digital signal will use the DAC's in your receiver.

As opposed to a digital coaxial connection? No.

 

[Dantheman89]

No offence to what MDS said but you dont have to get an optical cable, if the receiver has got digital coaxal connections on it the it would be cheaper to just buy you a standard composite video cable (yellow) an plug it in that way. You will get the same quality of sound out of that then you would the optical cable, and they both are better than your standard l/r connections

 

[mtrycrafts]

I've heard that toslink cables can have some problems with phase distortion but I've used them and not had any trouble.

That would be a good trick. I wonder where that phase distortion is introduced and how. Certainly not in the digital stream. Besides, it is buffered and re-timed.


You could say that the amplifier has to be good at interpreting digital signals sent through a toslink/electrical digital cable and the cable itself must be good in not distorting the signal (group delay etc.), but I doubt whether these have much bearing on sound quality.

Group delay? The digital streams are Reed Solomon encoded stream. Data all over the place, unlike an analog signal. Why would there be group delay and how would that happen?

 

[tbewick]

Hi Mtrycrafts

If I recall correctly, group delay always occurs because of no channel has infinite bandwidth. The bandwidth depends on the cable you use. The electronic properties of the cable are also affected by things like the dielectric used.

Coding methods are designed to be robust (error coding, self-clocking etc.) and handle such real world limitations.

 

[mtrycrafts]

Hi Mtrycrafts

If I recall correctly, group delay always occurs because of no channel has infinite bandwidth. The bandwidth depends on the cable you use. The electronic properties of the cable are also affected by things like the dielectric used.

Coding methods are designed to be robust (error coding, self-clocking etc.) and handle such real world limitations.

Group delay is frequency dependant, if I have it right. If so, it is not the same as 20Hz to 20kHz where the 20k will lag by some minute amount.
In CD digital, you have digital bits/bytes representing different parts of the music, not in sequence, and the digital bit stream frequency is pretty uniform? The time is what is critical and will be buffered then clocked, when DA takes place. Even if there is a group delay, questionable but not committing to it the buffer should take care of it.