[Split]Technical split from: Pear Cable CEO Calls James Randi's $1 Million Offer a Ho

[Dan O.]

That's what I'm all about.

Cables. Can they be made differently from one another?

Yes, Do you want an extreme example?

Consider a cable with a coaxial form with a hard outer shell for one conductor and a thin film attached to the outer shell by a flexible foam dialectic for the inner conductor and a hollow core. The opposing currents in the two conductors will create a force that will cause the inner conductor to move radially which will induce acoustic vibrations in the core. These acoustic waves will travel along the reverberation chamber of the core and react against the inner conductor causing it to move across the magnetic field which will induce currents in the conductor.

I'm not going to try to speculate what it's going to sound like on the speaker.

For a simpler example, just coil the speaker wires and the interconnect cables together. The resulting crosstalk should insure a good high frequency instability in the amp which if it doesn't destroy itself should at least muck up the frequency response.

For a more scientific analysis, I posted a link earlier to an analysis of several different speaker cables and the resulting interaction with the amp and speakers. The cables were just modeled by their bulk resistance, capacitance and inductance. which can be derived from the cable geometry and materials. The cables did have effects on the frequency response of the system but wether these effects could be heard is questionable.

 

[Paulhoff]

Consider a cable with a coaxial form with a hard outer shell for one conductor and a thin film attached to the outer shell by a flexible foam dialectic for the inner conductor and a hollow core. The opposing currents in the two conductors will create a force that will cause the inner conductor to move radially which will induce acoustic vibrations in the core. These acoustic waves will travel along the reverberation chamber of the core and react against the inner conductor causing it to move across the magnetic field which will induce currents in the conductor.

Oh PLEASE, if this were true, I would never been able to use my 440 ham radio, THE FCC WOULD SEND A LETTER TO ME TELL ME AND EVERY OTHER HAM TO SHUT DOWN BECAUSE OF THE RADIO INTERFERENCE TO THEIR RADIO EQUIPMENT ON THAT BAND AND OTHER BANDS. Just because someone can write something that sounds good, does not make it true.

Paul

 

[Cuddles]

I expect that much of this speculation is redundant anyway, seeing as how digital media these days don't reproduce any frequencies below 20 Hz or above 20 KHz , thus staying within the human hearing range.

The usual cutoff frequency is 22kHz (technically 22,050Hz). There is also a lesser-used standard for 24kHz that most PC soundcards can use, although I don't know about stereos, but this uses more memory and just isn't necessary in most cases. As Paulhoff says, CDs can easily reproduce below 20Hz and will certainly do so in music that wants to actually feel the bass as well as hear it.

 

[Dan O.]

Oh PLEASE, if this were true, I would never been able to use my 440 ham radio, THE FCC WOULD SEND A LETTER TO ME TELL ME AND EVERY OTHER HAM TO SHUT DOWN BECAUSE OF THE RADIO INTERFERENCE TO THEIR RADIO EQUIPMENT ON THAT BAND AND OTHER BANDS. Just because someone can write something that sounds good, does not make it true.

Paul

I seriously doubt that you have any coax that meets the description I gave. And even if you did, you aren't going to generate much acoustic energy at 440 Mhz. Was there something that I missed? I think I got all the cross products right.

 

[Paulhoff]

Yea,

Consider a cable with a coaxial form with a hard outer shell for one conductor and a thin film attached to the outer shell by a flexible foam dialectic for the inner conductor and a hollow core. The opposing currents in the two conductors will create a force that will cause the inner conductor to move radially which will induce acoustic vibrations in the core. These acoustic waves will travel along the reverberation chamber of the core and react against the inner conductor causing it to move across the magnetic field which will induce currents in the conductor.

I'm not going to try to speculate what it's going to sound like on the speaker.

Paul

 

[Dan O.]

The usual cutoff frequency is 22kHz (technically 22,050Hz). There is also a lesser-used standard for 24kHz that most PC soundcards can use, although I don't know about stereos, but this uses more memory and just isn't necessary in most cases. As Paulhoff says, CDs can easily reproduce below 20Hz and will certainly do so in music that wants to actually feel the bass as well as hear it.

A search for [CD audio frequency response] quickly shows that many consumer quality CD's reproduce sound in the range of 2 Hz to 20 kHz +/- 1 dB. The RED-Book defined the range for CDs as 20 Hz to 20 kHz. SACD appears to push the range to 44, 50 or even 100 kHz.

 

[Paulhoff]

A search for [CD audio frequency response] quickly shows that many consumer quality CD's reproduce sound in the range of 2 Hz to 20 kHz +/- 1 dB. The RED-Book defined the range for CDs as 20 Hz to 20 kHz. SACD appears to push the range to 44, 50 or even 100 kHz.

Yes, 20 to 20 khz is the spec. but not the limited on the bass end, I have seen DC on the output on wave files, and there is one program that I have that can remove it. You can see the shift on the graph for the wave file. One can't get much lower then DC.

Paul

 

[brettDbass]

The usual cutoff frequency is 22kHz (technically 22,050Hz). There is also a lesser-used standard for 24kHz that most PC soundcards can use, although I don't know about stereos, but this uses more memory and just isn't necessary in most cases. As Paulhoff says, CDs can easily reproduce below 20Hz and will certainly do so in music that wants to actually feel the bass as well as hear it.

I'm pleased to stand corrected.

I admit to laziness and used wiki as my source, which says the standard is only 20-20k.

Your info is very detailed, what was the source?

 

[Paulhoff]

I'm pleased to stand corrected.

I admit to laziness and used wiki as my source, which says the standard is only 20-20k.

Your info is very detailed, what was the source?

24kHz would be for 48kHz sampling rate.

Paul

 

[Cuddles]

I'm pleased to stand corrected.

I admit to laziness and used wiki as my source, which says the standard is only 20-20k.

Your info is very detailed, what was the source?

I based my post on PC soundcards. These have a standard sampling rate of (about) 44kHz, with many having the option of 48kHz. This gives maximum frequencies of 22kHz and 24kHz respectively. However, according to the posts just before yours, the actual audio CD standard does only go up to 20kHz. I assumed computers and CDs would follow the same standards, but it seems that isn't the case. Sorry for the confusion.

 

[pipelineaudio]

I based my post on PC soundcards. These have a standard sampling rate of (about) 44kHz, with many having the option of 48kHz. This gives maximum frequencies of 22kHz and 24kHz respectively. However, according to the posts just before yours, the actual audio CD standard does only go up to 20kHz. I assumed computers and CDs would follow the same standards, but it seems that isn't the case. Sorry for the confusion.

When they speak of a 20khz bandwidth, they're saying it is meant to be flat between 20hz and 20khz. In order not to have higher frequencies fold back or "alias" into the audible range, an anti-aliasing filter must be used.

In the case of a 44.1khz sampling rate that means that you only have 2 khz of space that makes a filter between perfectly flat at 20khz and COMPLETELY attenuated at 22.050 khz. This is not a cheap or easy thing to do.

 

[Paulhoff]

Well, to its credit, even Stereophile routinely does listening 'tests' (sighted reviews) AND bench tests of products under review. Why should Fremer or other audiophiles object if JREF insists on an objective measure of performance to pre-identify any speaker cables which can be *expected*, for utterly uncontroversial reasons, to 'sound different' from a normal run of , say, Home Depot 14-gauge speaker wire...usually by rolling off the highest frequencies (in other words, acting as a crude equalizer)

And what highest frequencies are you talking about and is it the Home Depot or the so-called audioplile cable that have the high frequency roll off.

Paul

 

[sthomson]

And what highest frequencies are you talking about and is it the Home Depot or the so-called audioplile cable that have the high frequency roll off.

Tones at a higher frequency sound qualitatively "louder" to human ears than tones at a lower frequency. If a cable (or another audio component) rolls off the higher frequencies (something that they all seem to do, looking at freq. response plots), it will equalize the perceived volume of the tones to a listener.

Fair enough... His sounds subjectively "better" than my 5.1 computer speakers, regardless whether that difference is caused by the audio cable (not likely, apparently) or his six-figure tower speakers, or some emergent property of the whole setup.

My 5.1 home audio system sounds better than my laptop speakers. Should we attribute that to the wires, or to the D/A, amplifier and speakers?

Should we trust someone's opinion more if they own lots of stuff? Should we trust them more than the experts that Randi has undoubtably consulted?

 

[krabapple]

And what highest frequencies are you talking about and is it the Home Depot or the so-called audioplile cable that have the high frequency roll off.

Paul

I thought it was clear, I was referring to certain audiophile cables that have been shown to purposely have a nonflat frequency response in the audible band. I believe pipelineaudio also references these early in the thread, referring to them as 'filters'.

As for the actual brand(s) , I believe the most infamous was the MIT Oracle (costing over $9000), which
had a mysterious little 'box' inline , that proved to be a passive equalizer. Look it up on rec.audio.high-end in Google Groups, you'll find a thread about it.

 

[krabapple]

And what highest frequencies are you talking about and is it the Home Depot or the so-called audioplile cable that have the high frequency roll off.

Paul

I thought it was clear, I was referring to certain audiophile cables that have been shown to purposely have a nonflat frequency response in the audible band. I believe pipelineaudio also references these early in the thread, referring to them as 'filters'.

As for the actual brand(s) , I believe the most infamous was the MIT Oracle, which
had a mysterious little 'box' inline , that proved to be a passive equalizer. Look it up on rec.audio.high-end in Google Groups, you'll find a thread about it.

Btw the RAH-E newsgroup also had its own cable challenge (with monetary reward of a few thousand bucks). I don't have enough posting mana to post a link yet, but here's the rules froma thread called 'Does anyone REALLY believe in cable sound?"

Is there *anyone* out there who really *does* believe that one cable
sounds better than another?

The prize pool is somewhere around the $2500 mark, and all you have to
do is demonstrate that you can hear the difference between any two
cables which meet a very simple level-matching criterion.

The basic rules are as follows:

Cables must be level-matched from 20Hz to 20kHz, within +/- 0.1dB at
the speaker terminals. Any conductor and insulation materials are
allowed, and any cable construction is allowed.

The test protocol will be double-blind ABX, implemented in whatever
way is both practical for the circumstances, and acceptable to all
interested parties. The test will comprise 20 trials, the 'pass'
criterion being correct identification in 16 out of the 20 trials.

The rest of the system (source, amplifier, speakers and listening
room) is at the choice of the test subject, as is the selection of
music, and the duration of the individual trials.

****************

 

[robinson]

Btw the RAH-E newsgroup also had its own cable challenge (with monetary reward of a few thousand bucks).

Interesting. You can post links without waiting by leaving spaces in them.

 

[Paulhoff]

Such an easy test to pass. The phase characteristics of the cable at frequencies over 1 MHZ can cause some amplifiers to exhibit unstable oscillations at those frequencies. The listener cannot of course hear those oscillations but a cleaver design or tuning of the amplifier could detect that oscillation and cause a noticeable phase shift or distortion in part of the audio band that a trained listener could detect.

An audio amp oscillationing a 1 mhz, what type of crap amp does that.

Paul

 

[Dan O.]

An audio amp oscillationing a 1 mhz, what type of crap amp does that.

The kind that the audiophiles prefer, with minimal filtering and lots of gain.

 

[Paulhoff]

The kind that the audiophiles prefer, with minimal filtering and lots of gain.

Please, that still would be a very poorly designed amp.

Paul

 

[Dan O.]

Did you check out this link? http://sound.westhost.com/cable-z.htm I posted it back on page 6 of this thread.

Apparently instability is a major concern for high end audio equipment. They blame it on high capacitance cables and solve it with zobel networks which add (guess what) more capacitance.