Cables can make a huge difference...

[TonyW]

I’m guessing recording studios capture a good portion but not all of the phase information during a recording session. And even the most competent stereo playback systems likely reproduce only a portion of the phase information captured in the recording. I think our brains fill in what’s missing. The more phase information present, the more realistic sounding the playback. I bet our brains are able to work with surprisingly little phase information to paint a holographic sound stage but of course the less extrapolation the richer and more realistic the experience.

 

[MarkusBarkus]

Yes, sound waves move through the air at different speeds relative to frequency

...is this accurate?

 

[DaveC]

I’m guessing recording studios capture a good portion but not all of the phase information during a recording session. And even the most competent stereo playback systems likely reproduce only a portion of the phase information captured in the recording. I think our brains fill in what’s missing. The more phase information present, the more realistic sounding the playback. I bet our brains are able to work with surprisingly little phase information to paint a holographic sound stage but of course the less extrapolation the richer and more realistic the experience.

It's the reverb trails that are truncated by both recording and playback systems. This is why psychoacoustically correct electromechanical feedback is part of the key to an excellent system.

What happens is sound from the speaker is transduced back into an electrical signal by many different parts of the playback system. The most obvious examples are vacuum tubes and turntables. But lots of stuff is affected by the sound of the speakers... the entire structure of the house and floor for one. AC power devices, capacitors, etc... maybe not to the degree of tubes and vinyl, but it all makes a difference, and the resulting transduction of mechanical sound back into an electrical signal that will them be played back again through the speakers has a significant effect on what we hear.

This is why we use special racks, footers, speaker stands, etc. what we're really doing is trying to reduce bad vibrations and promote good vibrations. In this case good means what our brain expects to hear, and is thus psychoacoustically correct, and bad means what we don't expect to hear or what is fatiguing, like alert sounds that overstimulate our nervous system.

The other way we can do this is mechanically... I once sat through a demo of small mechanical resonators that were placed inside a horn. The designer and builder of these devices explained that they were excited by the sound made by the speaker, then the energy was released later, like a tuning fork, in order to extend the decay and restore the truncated information. Well... IT WORKED! I was surprised it could be accomplished in this manner. Vocals sounded more vibrant and real, and the soundstage improved. Exactly what you hope for when you increase the overall resolution and fidelity of your system.

So playback is really complex... we're actually not just reproducing what's on the recording. Best case, and what sets a apart a really magical stereo from something a bit more ordinary, is how the system handles the inevitable electromechanical feedback, a great system uses feedback to produce a more psychoacoustically correct presentation that's actually closer to what the brain expects to hear while mitigating noise and feedback that is not psychoacoustically correct.

 

[TonyW]

...is this accurate?

Good catch. I misspoke. Thinking about cables when I said that. The phasing of a live band is relative to the positions of the singers and instruments. But the point I was making is that phase shift occurs in cables relative to frequency due to the capacitance and inductance of the wire. This affects the realism and naturalism of playback. That’s my theory in a nutshell.

 

[DaveC]

Good catch. I misspoke. Thinking about cables when I said that. The phasing of a live band is relative to the positions of the singers and instruments. But the point I was making is that phase shift occurs in cables relative to frequency due to the capacitance and inductance of the wire. This affects the realism and naturalism of playback. That’s my theory in a nutshell.

I agree with your observations 100% but I'm not sure there's enough reactance in a typical cable to cause significant phase shift. In many cases the LCR of the cable is simply added to the components immediately before or after, such as a pramp that has a capacitor coupled output or the crossover in a speaker, which is typically going to have much more reactance than the cable its self.

I think the effect you're hearing is more a result of spatial cues experienced as room reverberations and cables effect is more a result of smoothing over these fine details and reducing overall resolution.

A couple posts back I went into feedback and how extending decay of these truncated reverberations improves the overall listening experience by making the reverb trails more psychoacoustically correct.

 

[DonH50]

Here is the response of an RCA cable (Belden RG-6 1530A, distributed transmission line model with RLC for conductor and shield) 10 feet long used as an interconnect in a fairly high-impedance system having 1 k-ohm (tube) preamp output and 100 k-ohm amplifier input.

Relative to 10 Hz (the start of the simulation), at ~20 kHz amplitude is down 0.002 dB and phase shift is 1.2 degrees. Group delay change is 68 ps. This is due to the cable alone; source and load impedances are ideal resistors. Adding reactive elements would hide the effect of the cable.

 

[Robh3606]

Here is the response of an RCA cable (Belden RG-6 1530A, distributed transmission line model with RLC for conductor and shield) 10 feet long used as an interconnect in a fairly high-impedance system having 1 k-ohm (tube) preamp output and 100 k-ohm amplifier input.

Hello Don

That mirrors when I did my measurement using CLIO in the "loop" nothing there to concerned about measuring a 2 meter low cost cable.

Rob

 

[DaveC]

Here is the response of an RCA cable (Belden RG-6 1530A, distributed transmission line model with RLC for conductor and shield) 10 feet long used as an interconnect in a fairly high-impedance system having 1 k-ohm (tube) preamp output and 100 k-ohm amplifier input.

Relative to 10 Hz (the start of the simulation), at ~20 kHz amplitude is down 0.002 dB and phase shift is 1.2 degrees. Group delay change is 68 ps. This is due to the cable alone; source and load impedances are ideal resistors. Adding reactive elements would hide the effect of the cable.

View attachment 135673

View attachment 135674

Thanks, I agree adding reactive elements would indeed swamp the effect of the cable.

I suspect speaker cables would also have a very small effect on phase, FR or group delay.

I believe that the differences we hear in spatial presentation between cables is simply a result of resolution. A good cable will truncate reverb cues the least amount possible, and those spatial cues are in part what our brain uses to recreate the soundstage. If you want a 3-D immersive "you are there" soundstage, it requires maximizing resolution. Interconnect cables have an especially large effect on resolution.

 

[TonyW]

Thanks, I agree adding reactive elements would indeed swamp the effect of the cable.

I suspect speaker cables would also have a very small effect on phase, FR or group delay.

I believe that the differences we hear in spatial presentation between cables is simply a result of resolution. A good cable will truncate reverb cues the least amount possible, and those spatial cues are in part what our brain uses to recreate the soundstage. If you want a 3-D immersive "you are there" soundstage, it requires maximizing resolution. Interconnect cables have an especially large effect on resolution.

I cannot find a reason to disagree with these conclusions and I appreciate the Bode plot posted by DonH50. But it makes me wonder why some cable makers have those “network” boxes inline with their cables.

 

[DonH50]

Thanks, I agree adding reactive elements would indeed swamp the effect of the cable.

My original sim included a typical amplifier input (RFI suppression) capacitor but that buried the impact of the cable. The cable model incudes distributed resistance (different for center conductor and shield), inductance, and capacitance.

I suspect speaker cables would also have a very small effect on phase, FR or group delay.

A speaker cable having too high impedance (e.g. too small, too long, or both) for the speaker's impedance will affect the frequency response (etc.), but the amplifier's output impedance usually dominates the numbers. I have an article about that but not really relevant here, and I did not plot phase or group delay that I recall (phase is usually uninteresting as long as it is linear so group delay is constant).

I believe that the differences we hear in spatial presentation between cables is simply a result of resolution. A good cable will truncate reverb cues the least amount possible, and those spatial cues are in part what our brain uses to recreate the soundstage. If you want a 3-D immersive "you are there" soundstage, it requires maximizing resolution. Interconnect cables have an especially large effect on resolution.

What do you define as resolution? Spatial presentation implies time resolution to me, though amplitude gets involved since "softer" may sound "farther", especially with no visual cues.

If not distributed RLC, what in the interconnects contributes to (decreases) resolution?

What does it need to be to be (in)audible?

Sorry if you've already answered, hoping this might tie things together for me. In addition to the source material (recording, mixing, mastering), I would have expected speakers and speaker-room interaction to dominate the spatial presentation.

 

[treitz3]

Okay, gentlemen. This thread will be closed for a while. There are so many reports to go through, I don't even know where to begin. The moderation team will take a look and decide which direction to go from here.

It would be nice if a topic such as this could just be a cordial, casual conversation where everyone shares their experience and observations without all of the riff-raff. We are better than this.

Tom

 

[treitz3]

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[Holmz]

I've given this some thought. I have a theory why cables are more important in a playback system than in the studio.
Imagine standing in front of a live, acoustic band. Close your eyes and you can place the location of each of the instruments. That is because of phasing. This live band with several sources of sound is a jumble of frequencies and phasing. But even though the phasing is different this is how we can tell with our ears location- left, right, up, down, front, and back of all of the different sounds. This jumble of phasing from all of the various sources on stage sounds natural to us because this is our physical world. Phasing does not change with distance. Only amplitude changes with distance. And yes, high frequencies get dampened faster. So we all find our favorite spots to sit in a concert venue. Some like the front rows for a louder, more engaging concert, others like the middle rows for a balanced sound and some prefer the back rows for a more relaxed presentation. It's a matter of taste. While everyone is experiencing either a brighter or more mellow sound depending on seating position they are all experiencing the same phasing of the sound.

Put this band in a studio with multiple mics and pickups and now the studio must faithfully preserve this sound in a recording. As long as the microphone cables and pickup cables are identical then the phasing should be preserved. Note that no high powered amplifiers are used in the recording chain. That is a significant difference between studio and playback. (I'm not counting the high powered amplifiers used in the cutting lathes for making vinyl records). As long as the studio preamps and equalizers preserve phasing then the fidelity of the recording is maintained. Of course patch cords between preamps to recording device play a significant role in preserving fidelity but only after the recording is down mixed from multiple channels to two channels. And I think power cords, quality of power coming into the studio is just as critical as it is in a playback system. Any phasing information, any detail that is lost during the recording process is lost forever. So one question is: How much care do studios take in the use of power cords?

Now the playback system has the task of reassembling not just frequency and amplitude information but the all too important phasing information. The quality of reassembling the phasing information directly correlates to the realism and naturalness of the reproduced music. Most, not all of that responsibility falls to the speakers with the second most important component being the cables. The cables, being wires can't help themselves. They move signals at different speeds relative to frequency. Yes, sound waves move through the air at different speeds relative to frequency but the proportions between electrical wires and air is much different. So cables can alter the phase information in the musical recording. To complicate that, any speaker that is not a one way design such as a Quad ESL, has a crossover network that splits the frequency range of music and directs it to different drivers design to reproduce a specific range of frequencies providing more challenges to the preservation of phasing of the original music. So our playback cables not only need to reject noise, interference from the outside, but also try to maintain phasing as these signals traverse the wire. We see cables with network boxes and others that use a blend of dielectrics and wire materials to preserve phasing. I think that we find some wires work better with certain speakers than others because the cables need to compliment the crossovers with respect to phasing and also frequency response.

This is somewhat simplistic but still too long. The magic of it all to me is how I hear a 3D soundstage (left, right, front, back, up and down) as if the band is right there in front of me. But at the same time some of our hifi systems sound more real than real. It's not really hifi then, is it? What I mean is I can feel, not just hear the plucks on guitar strings- maybe in real life I'm sitting 3 feet from the guitar player. Or I hear clarity beyond what can be heard at a live session. It is the same as watching our HDTV's. We all, at least I do, have the color saturation, the contrast and the sharpness cranked up so that the picture looks more real than real. HDR was supposed to give us a more true rendition of the scene. HDR stinks.

Many speakers do not maintain the phase, although the Quad was one that did.
And I would doubt that most here look at step function response.

Arguing for time and phase correct cannot really be easily moved to a cable argument, as the cable move the signal through them with almost no effect upon phase.