Why cables?

MacLeod

First off, Im not trying to start another cable debate or be a smart ****. This is an honest question that I thought of today while I was driving around pondering audiodom as I often do. So please dont read any sarcasm or condescension into this.

Virtually everything of decent quality now has an optical out or at least a coaxial output. My CD player, my Xbox and DVD player all use digital outputs to my receiver. The only thing Im using cables for is my cheap **** cable box and VCR.

My question is, why use cables at all for audio (except of course when the source doesnt have digital outs)?? Especially Hi-Fi. Using an optical out is the purest, most transparant and most noise free way of connecting a source to an amp, processor, what have you. And isnt that the purpose of cables? To transport the source signal from device to device with as much transparancy and as little noise as possible?

Plus, when using a digital output, the signal is not having to be converted from digital to analog which is good because DA conversion ALWAYS adds some noise. Say if youre going from a CD player, RCA cables to a preamp, then RCA cables to an amp then out to the speakers youre going from digital to analog to digital to analog to digital and finally to analog again. Thats a TON of places noise can be induced. If you were to use optical outputs all the way, the signal would stay digital from source to the amp.

Now I know I cant be the first person to think of this so - what am I missing?

rskarvan

The signal is only digital until it goes through the DAC. After that, its analog through the preamp, amp, and speakers.

So, you only need a digital cable from your source to your DAC. Thats one and only one digital cable.

Make sense?

tonyb

Some people like analog sound better
Some have gear of different quality thus they may want to use the
D/A conversion in another piece.I personally like analog better than digital.
Matter of preference I guess.

jakelm

SACD, DVD-A, Phono..... Analog only

Everything else I have ...Digital

PolkThug

You guys still use cables? Wireless is where its at!

MacLeod

rskarvan wrote: »

The signal is only digital until it goes through the DAC. After that, its analog through the preamp, amp, and speakers.

So, you only need a digital cable from your source to your DAC. Thats one and only one digital cable.

Make sense?

I always thought that if a CD player has an optical output and youre using it, youre getting a straight digital signal. No converting. That would be only if youre using the RCA outputs. Why would a CD player convert from digital, to analog and then back to digital again???

tonyb

If you use the digital cable from your cdp to your receiver or pre/pro,then the receiver does the conversion to analog.Visa versa if you use analog cables from cdp to receiver.

Ferres

I notice a slight harshness with voices when using digital/optical. Going analogue seems more natural.

tonyb

PolkThug wrote: »

You guys still use cables? Wireless is where its at!

Hell...I just sing in the shower...can't get any cheaper than that,though
sq may suffer a bit.:)

mldennison

you have to convert from D>A at some point since your preamp, amp and speakers need analog. both your CD/DVD/SACD/DAD-A player and your receiver have D/A converters. if you are using the digital cable from the cd player to the receiver then the conversion is happening in the receiver. if you use the analog cable, it is happening in the cd player. people use the analog cable to take advantage of the best D/A converter in their system, depending on which one that is.

MacLeod

I always thought that if a component has a digital input and digital output and thats what you use then its not converting the signal but rather just "passing it thru".

I am thinking that if you use optical output from the CDP to the pre then to the amp and assuming they all have optical inputs and outputs, then the conversion is taking place at the amp before it sends it out to the speakers. And isnt it best to keep the signal digital as long as possible?

mldennison

MacLeod wrote: »

And isnt it best to keep the signal digital as long as possible?

well i think that is where you get into the grey are of "whatever sounds better in your system". it probably is better to keep the signal digital as long as possible, as long as the D/A converter in your receiver is as good as the one in your cd player.

dudeinaroom

I don't know of any amps that have digital inputs, maybe some of the digital amps do. I would think a purely digital pre-amp(no conversion just bass treble volume) would degrade sound, because you are not just attenuating the signal, but changing the actual digital signal(changing the so called 1s and 0s)

mulveling

I prefer to keep my hifi optical cable-free...the amplitude values of the audio signal are digitally transmitted perfectly, yes, but the timings of these values are outside the digital domain. You're relying on the clock in some crappy cheapo TOSLINK transmitter chip to not botch things up too bad...and the receivers in most DACs can attenuate but not eliminate jitter originating from the source. If everything worked like a Chord DAC 64 in maximum buffer mode, source jitter would be almost a non-issue; unfortunately that's not the way most things work.

In my systems I prefer to keep things pretty basic & simple - Convert to analog as soon as possible and then keep the analog path to the speakers as clean as possible (which will be dependant on your system's needs).

Sure, the audible effect of jitter is very debatable, but sometimes the high-end is just as much (or even more) about getting things right in theory, as it is in reality

MacLeod

dudeinaroom wrote: »

I don't know of any amps that have digital inputs, maybe some of the digital amps do.

I think thats what I was missing.

I was under the assumption that most "quality" amps had digital inputs. I just browsed around some sites and youre right - none do that I can find.

That makes a lot more sense now. Thanks for the enlightenment fellas!

MacLeod

mulveling wrote: »

In my systems I prefer to keep things pretty basic & simple - Convert to analog as soon as possible and then keep the analog path to the speakers as clean as possible (which will be dependant on your system's needs).

In my car system, I use an Alpine processor. I dont have a head unit with an optical out (cause theyre F'ing expensive) so I use analog. And Ive got one noisey ****!! There is a distinct hiss at high volumes. Im able to overcome most of this with gain settings but its a trade off because you lose output. For the most part Ive got the noise quiet enough but if an SQ judge wanted to get picky and use a 0 bit track and crank the volume or hell just push PAUSE and crank the volume, he would think there was a snake in the car!

The noise comes from going from the CD (digital) to analog then into the processor, being converted back to digital, run thru the EQ's and x-overs, then back to analog and then out to the amps. Those 3 changes right there cause a TON of noise. This is what got me thinking about this in terms of HA.

mulveling

MacLeod wrote: »

In my car system, I use an Alpine processor. I dont have a head unit with an optical out (cause theyre F'ing expensive) so I use analog. And Ive got one noisey ****!! There is a distinct hiss at high volumes. Im able to overcome most of this with gain settings but its a trade off because you lose output. For the most part Ive got the noise quiet enough but if an SQ judge wanted to get picky and use a 0 bit track and crank the volume or hell just push PAUSE and crank the volume, he would think there was a snake in the car!

The noise comes from going from the CD (digital) to analog then into the processor, being converted back to digital, run thru the EQ's and x-overs, then back to analog and then out to the amps. Those 3 changes right there cause a TON of noise. This is what got me thinking about this in terms of HA.

Ah, I see. Well, a home hifi component 2ch system is very very different than a car audio system (I have no experience with car systems) Maybe optical is the way to go there.

F1nut

Mac, have you ever tried bypassing the EQ's to see if the hiss goes away?

danger boy

i guess it comes down to what sound you are trying to get.. some prefer the sound their CDP puts out.. while other people like the sound of their receiver/pre amp. there can be differences in sound..

plus if you use the analog outputs on your CDP, you can somewhat adjust the sound using different cables/interconnects.

NeilGabriel

Don't want to hijack this, but a friend was asking me the other day about digital speakers (believing that they played digital sources I guess)...and I paused...in my analog brain, I assumed that at some point the signal has to be converted to analog to run all speakers of which I am aware. That occurs behind the amp stage because the amp just adds power to the signal received (which has been made analog by a cd player or preamp). Any comments on the digital speaker concept? Does my mp3 player have a d/a convertor?

engtaz

NeilGabriel
It's BS. A speaker is a analog device.

MacLeod

F1nut wrote: »

Mac, have you ever tried bypassing the EQ's to see if the hiss goes away?

Yeah, it goes away. This is a very common problem when using digital processors with analog inputs and having the signal converted 3 times before it hits the speakers. However the Alpine does seem to be a little worse than the others.....but then again its such an excellent piece its worth the trade off.

8 channel, 31 band EQ's
8 channel variable crossover from 20-20 KHz
8 channel time alignment in .05 ms increments
8 channel phase control
8 channel level control

Just cant be beat.

Maybe one day Ill have $800 lying around and will be able to afford a head unit with optical out.

mulveling

NeilGabriel wrote: »

Don't want to hijack this, but a friend was asking me the other day about digital speakers (believing that they played digital sources I guess)...and I paused...in my analog brain, I assumed that at some point the signal has to be converted to analog to run all speakers of which I am aware. That occurs behind the amp stage because the amp just adds power to the signal received (which has been made analog by a cd player or preamp). Any comments on the digital speaker concept? Does my mp3 player have a d/a convertor?

Meridian makes some very high end speakers that just take a digital input. All the necessary DACs, amps, and crossovers are inside the speakers. A good friend of mine has auditioned such a system and says it sounds awesome...at least on par with our mutual friend's Thiel CS7.2 system (though that rig is still being tweaked and optimized). Pretty cool stuff, and pretty good for a somewhat plug & play system.

Normally this kind of setup would be a nightmare (think computer speakers) but Meridian knows what they're doing.

rskarvan

NeilGabriel wrote: »

Don't want to hijack this, but a friend was asking me the other day about digital speakers (believing that they played digital sources I guess)...and I paused...in my analog brain, I assumed that at some point the signal has to be converted to analog to run all speakers of which I am aware. That occurs behind the amp stage because the amp just adds power to the signal received (which has been made analog by a cd player or preamp). Any comments on the digital speaker concept? Does my mp3 player have a d/a convertor?

Yes, your mp3 player does have a d/a converter.

TN_Polk_Lover

NeilGabriel wrote: »

Don't want to hijack this, but a friend was asking me the other day about digital speakers (believing that they played digital sources I guess)...and I paused...in my analog brain, I assumed that at some point the signal has to be converted to analog to run all speakers of which I am aware. That occurs behind the amp stage because the amp just adds power to the signal received (which has been made analog by a cd player or preamp). Any comments on the digital speaker concept? Does my mp3 player have a d/a convertor?

As engtaz said, yes speakers are analog devices. The speakers that are advertised as "digital" have a class D amplifier built in. The digital to analog coversion takes place in a DAC built in to the class D amplifier. Of course, the signal to the speaker drivers is analog.

The supposed benefit of the "digital" speaker is that the crossover function can be done in the digital domain. Since the characteristics of each driver (woofer, midrange, tweeter, etc.) is known by the manufacturer, the proper crossover characteristics can programed into the processor to be split before amplification.

Now, whether or not this makes for a better sounding speaker, that is another thing. Personally, I've never heard one of these "digital" speakers, so I can't speak to that.