Axiom Home Page Forums General Discussion Home Theater interconnects

I perceive a dig towards justifying expensive cable here.

If you look a bit closer at a couple of key points that Alan makes, you should be able to answer this question pretty easily (although Alan can correct me if i've mis-used his info).
He states that:
"Long shielded cables can have capacitance effects that will affect high-frequency response. If the latter is attenuated..."
This is the very reason why GAUGE of the speaker wire is more important than the 'technology' of the wire. The higher gauge speaker wire can carry a heavier load and reduce the attenuation of the signal over long runs (more explanation on this below).

"Frankly, I've used cheap and expensive coaxial digital interconnects and never heard a difference, nor should there be any if you understand how the above digital signals work. Nor is there any audible difference with optical digital connectors."
There is no disputing this really. It is kind of hard for a digital signal to degrade when the signal itself is essentially a bunch of zeroes and ones decoded back into an analog signal before the end link. Even if the zeroes and ones somehow lose some of their signal over the run, the end component still only has to distinguish zeroes and ones. A 'faded' zero or one won't change the way the sound is played but in an analog signal, a faded frequency is played accordingly.

Alan also states:
"With analog video, we're talking major differences with long interconnects because video signals are MILLIONS of Hz (megahertz)."
Keep in mind most music plays in the human hearing range of 20Hz to 22, 000Hz (or 22khz). Hence, speaker wire does not carry the same frequencies that a video signal does.
If we apply Planks Law of electromagnetic physics, the energy of an electromagnetic wave is in proportion to the frequency of the emission and inversely proportional to the wavelength. The energy of the signal is higher with increasing frequency and with decreasing wavelength (shorter wavelengths). And, short wavelengths attenuate faster than longer wavelengths. Therefore, one could conclude that the much higher frequency (and shorter wavelength) video analog signals are more likely to attenuate compared to a longer wavelength signal such as that which occurs through speaker wire. If you increase the distance over which that signal travels, you increase the chance its attenuation occurs to the point of, as Alan stated once again:
"...capacitance effects that will affect high-frequency response."

I have yet to see an entertainment setup in which someone has placed the dvd behind the couch with the tv in front of them requiring a 40 foot video cable run but if anyone wants to try, i would love to hear the results.

chesseroo

i'm not trying to justify expensive cabling, i was simply curious on the real difference between the two. your explanation made a lot of sense. i don't know much about electromagnetic broohaha, but your explanation was very understandable. I do wonder, however, if interference could cause attenuation in speaker cable.

Ravi, i'm just poking fun. I considered some more expensive speaker wire myself but more for the looks than anything. I still settled on some stuff slightly more than common zip cord but primarily b/c of the flexible jacket and the great price i got.

I would not be too concerned with EMF interference with your speaker cable. EMF interference is cut down a considerable amount by the outer jacket alone in the same way that a single pane window can cut down over 80% of the UV rays from the sun even though it feels warm on your arm.
I am guessing that the signal from the source to the speaker wire will be strong enough to display the same sound as a wire 'shielded' by some other metal wrapping. Distance between your wires is also another consideration. If anyone does not know much about electrical signals, i would tell them in the least NOT to wrap their wire bundles together and especially not with the power cords.

The only way to know for sure of any sound diff b/w highly shielded and not so shielded wires is once again to listen (or view as the case may be) for oneself.

Hello Ravi,

Thanks. Old hand Chesseroo made lots of good points taking off on my commentary, but one subject I didn't fully address was the matter of gain--the electrical strength (or weakness) of the analog signal through interconnects or speaker cables.

The "line-level" signals from a preamp or RCA connector are typically 1 volt or so, and a few thousandths of an ampere (very tiny) so the cables have to be shielded to screen out electro-magnetic and radio-frequency interference (RFI). If they weren't shielded and just one 3-foot length was placed anywhere near a 110-volt AC power cord, you'd get unlistenable quantities of hum!

But the signal through speaker cables has lots of amplifier gain applied (in the amp). Your amplifier makes the tiny 1-volt line-level signals thousands of times stronger, so when they emerge at the speaker outputs, they're from 20 to 50 volts and lots of amperes (sometimes) instead of milliamps (teeny-tiny).

So it's a matter of signal-to-noise, which means any interference is at such a low level that you'll never hear it because the audio signal from the amplifier to the speakers is so much stronger. (Digital signals through optical connectors are totally immune to all kinds of interference.)

Sometimes, in an eccentric installation, speaker cables can pick up RFI. When I worked at CBC Toronto in the late '60s, I lived only a block away from the old CBC TV transmitter on Jarvis St. I was getting the television sound when I listened to records on my audio system! Eventually I found the source: the speaker cables were serving as an antenna and conducting the signal back into the amplifier, where it was rectified (converted back to an audio signal) and amplfied along with the audio signal from my turntable! It only happened because I lived 100 yards from the TV transmitter.

The cure was to install shielded and grounded speaker cables between my speakers and amp. But that was a very unusual situation. Normally, you don't need shielded speaker cables, but if you have RFI problems, they are often required to eliminate the interference.

Regards,

Alan

I appreciate the response. I figured it was a bigger need for shielded interconnects because the signal was very weak, but your electrical engineering style explanation was fun! I always like to pick up more jargon!

chesseroo,

Backing up a bit to your previous comment about using optical for HT and analog for CD from your DVD player. I do just that from my Sony DVD player. I have the analog outputs going into my CD inputs in my receiver and the optical/digital imputs into my DVD input on my receiver. That way I can switch back and forth between the CD and DVD even when just playing music. THis is how I discovered the lack of "output" to the tape recording output jacks when using the optical input from the DVD player. i.e. if I want to record a cassette tape from from a CD, I have to use the analog (CD) input to my receiver. If I switch over to the optical (DVD) input on my receiver, there is no signal going to the tape outputs so I cannot record to the cassette!

No big deal (considering the fidelity of cassette) but just a curosity. I think you should try a similar hook up (providing you have standard analog audio outputs on your DVD player - and you should!
If you don't have separate DVD and CD inputs on your Onkyo - try the "aux" input!

Give it a look and see if you can.

Randyman

That's a great suggestion.
I never thought about the switching inputs deal. I believe that is 'doable'.

thanks, now if only i had my new dvd...

Chesseroo,

If I can throw in a comment, I had a similar experience with my DVD player when I was rapidly gaining an understanding of all the techie jargon i.e. how to use it as both a music and movie player.

In the setup menu for your DVD player, there is probably someplace where you can choose how signals will be sent to the receiver, either digital "Stream/Bitstream" or analog "PCM", or both. If you select both, whatever software is read (either DVD or CD), the player will send both analog and digital signals to the receiver. Plug your analog interconnects into the "CD" input on the receiver, and the TOSlink/coax cable into the "DVD" input, to do the 2 input trick.

When you play back music with the receiver in "CD" mode, a digital signal will simultaneously be sent, but will simply be ignored by the receiver. Likewise, in "DVD" mode, the receiver will also be fed a 2-channel analog signal, but it will be redundant.

As a word of caution, DVD players are notoriously awful with 2-channel music if the rest of your system is good enough to reveal it (which in your case with an Onkyo and Axioms, it probably is). In fact, I A/B tested my 15 year-old Technics CD player vs. a Denon DVD changer, and the Technics performed better with 2-channel.

It all boils down to what a piece of hardware has to do. A receiver has the difficult tasks of decoding surround soundtracks and powering speakers. Asking it to do anything other than that, in particular handling music, is a crapshoot. Likewise, A DVD player has to handle complex video processing. Considering the average DVD player is the same size as a CD player, how much circuitry in the player is actually devoted to music processing?

What were you saying about hitting eBay again?

Hi fhw,
I had absolutely the opposite experience when I compared my old dedicated cd player versus the fairly new Toshiba 2800 DVD player. Within just a few notes I began to realize just how much music I have been missing. It was very similar to the first time I heard my old music through new Axioms.
Good Listening.

Hey fhw,
All that digital signal processing/decoding etc. is done inside tiny little integrated circuits (ICs) They don't take up much room inside the receiver or the DVD player (as long as they are not constructed with that super high grade exotic speaker cable!!!) Heh heh!

When it comes to decoding audio or video (inside a DVD player), I think most newer units do both pretty well. I am surprised that your older technics player sounded better than your new DVD player. I only bring this up because of the newer Super Audio CD and DVD-Audio formats. Both require higher end (better/more sophisticated) decoding/processing units and most of the units that play these high end formats are ALSO DVD players.

I am "waiting" to upgrade my DVD player so (hopefully) I can find a 5 disc changer unit (with DTS decoding?) and progressive scan output that plays DVD-A and SACD! Nobody does that yet - but I am hopeful some good company will soon.

All the best!

Randyman