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Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
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Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
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In Reply to: Is there anyone here who can muster a hypothesis for why the ground loop on speaker wires works? posted by Norm on January 5, 2013 at 13:41:15:
Most likely several things are happening.I'm am going to simplify my answers here because the technical explanations involves a complex understanding of numerous disciplines in electronic theory. Frequency, propagation, what is implied by impedance, and other complex electronic functions to name a few. The scope of which is too complicated for a response to this post.
Figuratively speaking, for any load to function there needs to be something for the signal to push against. In a loudspeaker connection this is the negative (return, ground or whatever you wanna call it). In order to maintain balance this return needs to be neutral and equal. By bonding the grounds you by nature make them equal. In some cases this can improve the sound. The case of unstable grounding schemes in some amplifiers is one example already given in the responses.
However, some amplifier designs do not use earth ground as the neutral return, but instead "float" the outputs. This is not uncommon in older tube equipment. Now while this works for the function of the amplifier, it does not guarantee any equilibrium between the two loudspeaker loads. Also bonding the returns in this way may make some amplifiers more unstable, depending on the output circuit topology and how the "float" reference is derived. These factors become even more complex when two separate mono amplifiers are employed in stereo.
Another affect may be in damping factor. By eliminating a given length of the speaker wire you effectively increase damping factor. This will affect the sound particularly in the lower frequency octaves. From a practical perspective the speaker wire is the most limiting factor in real-world systems in regards to the overall system damping factor, so changing this affects the sound in a noticeable way. Damping factor is a real thing and can be heard and demonstrated easily. It's effects are most noticeable in the three lowest octaves of the audio spectra. You can hear the differences by comparing a long length of cable versus a much shorter cable of the same type. The longer wire has "slower" low frequency impact. This is a direct affect of a lower damping factor figure. BTW, damping factor issues is what lead to the idea of using mono amplifiers with short speaker wires and the idea of bi-wire. The improvement heard by doing these things are most due to a substantial increase in the damping factor figure. This fact has been obscured by the audio mystics, but I assure you this is the primary audible improvement achieved by these two methods, mystical suppositions notwithstanding.
Why some cables make a change while others do not? Well, quite honestly, it depends on how neutral the cable is. Most are not in the audiophile world. Most embody this concept of distorting the sound in some way to achieve a given "warmth" or "body" for marketing purposes. Very few audiophile cables are truly neutral. What goes in is not what comes out. It is these electrical games that have been toyed with by cable manufacturers to please enthusiasts, is what makes the changes either show up or not in this application. No audiophile cable actually sounds better, however they all sound different. Which ones are neutral is a matter of putting a signal in one end, and getting the closest signal to the input as possible. That's transparency.
And this cannot be determined by listening, only by measuring. To many other factors and variables come into play when listening because the cable cannot be isolated in an overall system. It's only one part of an integrated system of electronics interacting with each other in unique ways. By measuring the cable in isolation and comparing the signal put in it to the signal coming out using known predetermined and standardized variables, tells you whether the cable is neutral, unaffected by the equipment it's connected to.
Whether or not, a not so neutral cable "sounds better" is wholly subjective. Myself, I prefer knowing what goes in, is what is coming out. I don't listen to gear. I listen to recordings of music. I don't want to hear my equipment. So you will never hear me say some piece of gear sounds better. It's too subjective and my desires may not match anyone else. I will say they do sound different, and IMHO that's not good.
On that note, what should one buy? The industry plays so many games and are able to muster up so much whimsical audiophoolery by evoking sometimes mystical nonsense it is amazing that anyone can make a reasonable choice. It's why I do not design for high-end audiophile companies anymore. I left the industry for this reason. The lies and deceptions perpetrated by this industry now are just beyond my ethical standard, regardless of how well they paid me. But it does make for some interesting discourse. Doesn't it?
Anyway, other factors involving the OP's question come to mind as well, but I have said enough already. You guys can chew on this for a while.
JRL
Edits: 03/25/13 03/25/13 03/25/13 03/25/13 03/25/13 03/25/13 03/25/13 03/25/13
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Follow Ups
- RE: Is there anyone here who can muster a hypothesis... - jrlaudio 11:39:19 03/25/13 (0)
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