Sean & Unsound - excellent information.
Anyone that's been to CES or one of Hifi Expos has seen that
Dave Wilson alway uses short interconnects and long speaker
cables. His demo rooms always have great sound.
While I currently run long interconnects/short speaker cables, I was planning to switch things around. Mahalo for
the additional motivation.
Aloha. |
Of course there are practical limits. Adequate distance from components can keep all kinds of grundge (EMI, RF, etc.) at bay. |
I knew where you were coming from Unsound and appreciate the support. However, i just wanted to make it clear that there are obviously different takes on the same subject and i'd love to hear some of the various points as to why they think / feel the way that they do. Sean
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Sean, I agreed with your origianl post and I thought David A. Wilson's article mentioned some other significant points as well. |
Great post sean,the speakers I use, decapo i's,have virtually no crossover so I believe the resistive load my push pull class ab tube amps see is quite low which is why my volume setting never gets passed 11:00 o'clock.The little vtl tiny triodes at 25watts triode pack a wollop with a twenty five foot run of wire.I believe its best to have equipment far away from speaker vibrations and in my case the rack is on the side of the room with a couch next to it for damping/sitting purposes.This setup will be advantageous when I buy a table which will be less excited than if it were between the speakers. |
Unsound: Just as there are well known professionals that agree with me, there are going to be just as many that will argue the opposite point of view. I am not going to say that i am "right", only that i believe what i do based on the above technical reasons and quite a bit of listening experience.
I presented the above info so that others might have better understanding of the situation from this specific point of view. Hopefully, someone will provide rebuttal from the other side of the fence. This would allow us to compare notes and possibly learn from each other. After all, that is what these forums are all about, exchanging information, sometimes from opposing points of view, so that we can further our understanding on technical subjects and various products dealing with audio. So long as we can do this in a civilized manner, we all win. Sean
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None other than David A. Wilson agrees with Sean. This is from an article in "the absolute sound" issue 63 jan/feb 1990. I believe that copies are no longer available due to a fire. With that in mind I'm sure (hope) that "the absolute sound" will forgive me for borrowing this excerpt.
"Recommendations
My preference is to run relatively short interconnect lenghts when possible. I know this flies in the face of the conventional wisdom of the last 40 years. Just remember that the old approach of power amps near the speakers hearkens from the days of damping-factor 6, 20 watt amplifiers, and low-capacitance paper-dielectric interconnects. Vacum-tube power amplifiers should never be placed in the strong mechanical vibrational energy fields surrounding loudspeakers. Long speaker cable runs are not as destructive as they may seem. The impedance that exist in the power amp out-put stage/loudspeaker interface network are generally quite low, usually well under 75 ohms, so reactive loses in that interface are usually insignificant. Remember, too, that with the very low power-amp-output impedance common today, as well as the beefy cables generally used, effective damping factor is still quite high."
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The points being brought up about speaker cable impedance altering crossover points does not really come into play in the real world. If one were using cables with drastically different electrical characteristics for each individual driver / frequency range, i could see this becoming a factor. Otherwise, all of the drivers / crossover points are subjected to the same equivalent load introduced by the speaker cable and will act accordingly.
If one were to change individual runs of speaker cable BETWEEN the passive crossover components within the speaker and the individual drivers, one could measurably alter the hinge points and cause a lack of "synchronicity" within the speaker itself. The end result would be drivers that no longer crossed and blended at the factory specified rates, resulting in a lack of continuity from driver to driver with increased irregularities in frequency response. This could also drastically effect both vertical and horizontal radiation patterns due to cancellation between the drivers, etc...
When changing speaker cable, what does change is the total Z ( impedance ) that the amp sees. Some amps are very sensitive to terminating impedances, various levels of reactance, etc... This means EVERYTHING from the binding posts back. In some cases, using 6 ft of Brand X wire and then switching to 18 ft of identical wire MIGHT make both a measurable and audible difference. After all, any electrical characteristics that the cable might introduce into the system would have been tripled in this specific case. Obviously, this would be most likely to occur on amps that were not extremely load stable AND if using cables that were highly reactive ( either very inductive cables like zip cord or highly capacitive cables like Goertz, Polk, various braided designs, etc... ). The more stable the amp and less reactive the cables, the less likely you are to notice anything other than increased series resistance. Since most speaker cables are typically of relatively heavy gauge to begin with, it is not a big deal.
As far as Ernie's comments go about running long balanced lines, most of it is true, but maybe not for the reasons that he's thinking. Running balanced ( aka "XLR" ) type cables does have some very specific benefits. Before going over those, let's look at how a balanced design works.
In a "normal" ( rca or "single-ended" ) cable, one has a "hot" or positive wire and a ground wire. In a balanced line, you have one positive wire, one negative wire and a wire that is ground. By using this approach, you can have a voltage ( or level of "gain" ) that is twice that of a single ended circuit. This is because we can swing voltage both above ( positive ) and below ( negative ) zero volts ( ground ).
In a balanced installation, a signal is fed onto the positive wire and the inverse of that is fed into the negative at the source end of the chain. At the load end, a circuit is used to compare the two signals. If there are any variances that cause the positive signal to diverge from what the negative shows ( or vice-versa ), the "distorted" or "non-linear" part of that signal is not reproduced. These "distortions" can show up as being differences in signal amplitude between positive and negative, differences in phase, etc... The bottom line is that, if the signals don't jive EXACTLY ( or as close as is humanly possible to design into a circuit ), that part of the signal is not reproduced.
Obviously, this gives us two noticeable advantages over a single ended design. First of all, we've increased the drive levels from the source to the load. Just as i stated with amps & speaker cables vs components & interconnects, the more signal that you have, the more you can afford to lose without noticeable degradation. As such, they can afford to "lose" a little bit of signal using phenomenally long runs ( with the resultant higher series resistance ) as they've drastically increased the amount of signal that they had to work with.
Besides the above, most professional installations make use of compressors, expanders, effects units, equalizers, noise gates, mixing boards, etc... Since most every one of these mentioned has the potential to add gain to the signal if adjusted in that manner, it is possible to take a signal of microscopic amplitude and boost it enough to blow your eardrums out. Signal loss is NOT a big deal unless one is worried about the "ultimate in audio reproduction". As most of us know and have heard, the majority of the professional recording and sound reinforcement field do not consider this a priority. Keeping the noise out of the system and capturing "most" of the musical event is good enough.
The second advantage is that this approach is obviously a lot less susceptable to outside interference. Since most RFI / EMI is introduced via some type of varying magnetic field, the interference does not ( typically ) show up in the same amplitude and phase on both the positive and negative runs. As such, it is simply cancelled and you are left with a lower noise floor and extremely minimal outside interference.
If you noticed, i said that the second advantage was from OUTSIDE interference. The cables themselves can introduce errors into the system. If the cables make use of lossy materials with non linear levels of dielectric absorption or have specific levels of reactance that cause frequency response abberations, the sonic traits of this cable WILL be passed down the chain. This happens due to the fact that the use of identical materials used on both the positive and negative runs of wire would present a "match" that was still balanced between the two, even though they are distorting the signal. As such, a longer set of cables will still introduce more of their own sonic characteristics into a system than an identical yet shorter cable would. As such, one still needs to keep cables as short as possible and purchase cables that make use of high grade conductors and insulating materials IF one is looking for the most "transparent" system possible.
In terms of potential problems with the amplifier / speaker interface due to driver control and damping, this should not be a problem in the least. That is, so long as one selects cables that are MORE than capable of handling the power levels being generated within the system and are of low enough series ( "loop" ) resistance so as not to impede the flow of current in any way, shape or form. As such, i personally prefer an "overkill" approach when it comes to speaker wire gauge.
Selecting an amp that is both well designed and suitable to drive the specific load that they will see is also desirable and highly recommended. Otherwise, one might have to result to "band-aids" such as shorter speaker cables to reduce series resistance for "under-muscled" amps. In some cases, going to very small gauge cables to introduce series resistance / minimize communications between the amp / speaker interface also works. If the latter sounds crazy, believe me, it is true. Such may be the case when one has VERY reactive loads and / or amps that have a hard time with that specific type of load.
Some cable manufacturers take all of these factors into account and even provide charts as to what speaker cables they recommend for specific power levels. The smart ones also consider that the length of the run ( series resistance ) can come into play in such a situation and recommend heavier gauge cables for longer runs. This is not to say that you will personally like the products that these manufacturers produce, but to say that they are at least applying common sense, science and engineering to their designs. Companies that can provide no reasoning as to why or how their products work the way that they do are probably selling snake oil at exhorbitant prices. Sean
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We are talking about nano seconds of difference in electrical signals and until someone can validate the human brains ability to differentiate these miniscule packets of information I would prefer to put a small pillow behind my bald head and change the sound of my system that way or cup my hands near my ears as my wife shakes her incredulous head. |
These are out of Revel Speaker manuals:
NOTE: “Loop resistance” is the
DC resistance measured at one
end of a loudspeaker cable, with
the other ends shorted together.
Use high-quality speaker cable with a maximum total loop resistance
(for each wire run) of 0.07 ohms or less. Use the chart in
Figure 14 below to determine the maximum wire gauge.
A high loop resistance will result in mis-termination of the
filter networks, and serious degradation of sound quality.
Use high-quality connectors on the loudspeaker cables.
WIRE GAUGE (AWG) LENGTH (FEET) LENGTH (METERS)
6 87 27
7 69 21
8 58 18
9 43 13
10 34 10
11 27 8
12 22 7
13 17 5
14 14 4
15 11 3
16 9 3
17 7 2
18 5 2 |
I would guess in Simon9's case there would not be much difference as the two situations are not much different. Sean makes good points:
Along the same lines, if the signal is distorted due the materials used to construct the cables themselves OR the cable is of a poor design geometry resulting in improper impedances OR outside influences such as RFI and EMI enter into the equation, those distortions will be amplified further down the chain. It is not uncommon for problems with RFI / EMI to manifest themselves through interconnects due to broken grounds, poor design or poor connections. These problems are FAR less likely to arise with speaker cables unless using highly reactive ( inductive or capacitive ) cables or drastically long lengths.
To top it all off, interconnects use small gauge wires.
But it seems that if an interconnect is WELL designed (shielded etc.)and of sufficiently low resistance then long runs are okay. Have any measurements been done to show actual loss of these low level signals?
Shorter speakers cables would better damp the speaker drivers and while less immune to RFI, wouldn't the higher current in speaker cable make transients, phase shift, etc. more effect of the cable than low level signals in I/C's?
Well, I know what I mean, just can't say it :-( |
Check this out:
http://www.tnt-audio.com/clinica/wirecalculator.xls
and this
http://www.tnt-audio.com/clinica/cat5questions_e.html
for some info on the affeexts of cables length etc... |
Uh oh! C'mon Sean, I'm not too sure about your explanation of this, and I'm tired. But the biggest issue re the problem with longer speaker cables is the fact that the amp sees them as part of the passive crossover network of your speakers! If there's even a small impedence change then the crossover will shift, resulting in a spectral coloration.
If you run XLRs you can run HUNDREDS of feet between a robust CDP and a great, transparent pre with NO issues. The recording pros do it all the time! I chose to run longer, asymmetric (yikes, eh?) XLRs between pre and monos, and shorter speaker cables. Glad I did. I'm forgetting some of the other reasons for this, but it also has to do with the source component's signal being voltage-driven, while the amp's issues in driving lines and crossover networks and drivers is a current thing, which is therefore more sensitive to cable length loading. Recording engineers ALWAYS run long mic cables to pres rather than long speaker cables. Can we get an engineer in here who hasn'y forgotten what he learned in a marijuana haze back in school in the 70's (me!)?? |
Dammit Spluta, you &*/@#? !!!
Thanks Sean. It would be nice to collect into one place all of the audio myths, bad information, and questionnable conventional wisdom. Shouldn't take more than a terabyte or so. |
Sean.. Nicely put.
Everytime i try to explain something on
tech side it never comes out like that.
I get yelled at. :-) |
Sean, you have saved me a few thousand dollars with your narrative today. i was about to do the wrong thing.
Thanks |
Thank you shawn for laying to rest what I consider to be the latest hallucination in audio interconnects.Simple electrical properties awareness will validate your observations.I use 25ft runs of speaker cable and there is no sonic difference between it and a 8ft. run, none whatsoever. |
Let's look at this logically. I'll try to do it in plain English so that everyone can follow along. The strength of a signal at line level (interconnects) is very low in voltage and current. Losing ANY of this signal is equivalent to never having it appear at the source. This shows up as a lack of resolution in a system. After all, once information is lost, it can't be recovered nor could it ever be amplified to a listenable level. Along the same lines, if the signal is distorted due the materials used to construct the cables themselves OR the cable is of a poor design geometry resulting in improper impedances OR outside influences such as RFI and EMI enter into the equation, those distortions will be amplified further down the chain. It is not uncommon for problems with RFI / EMI to manifest themselves through interconnects due to broken grounds, poor design or poor connections. These problems are FAR less likely to arise with speaker cables unless using highly reactive ( inductive or capacitive ) cables or drastically long lengths. To top it all off, interconnects use small gauge wires. This results in greater series resistance. The higher series resistance opposes the flow of signal and causes signal to be absorbed by the cables themselves. This is due to what is referred to as "line loss". This becomes far more prevalent as the length of the line increases. While ALL cables have line loss, some are better than others by measurable amounts. As such, one would want the weakest signal to travel the shortest distance possible using the highest grade conductors and insulators prior to amplification. This would be done in order to minimize unrecoverable losses, minimze distortions within the cable / system itself and to reduce the potential for outside interference via RFI and EMI. As far as speaker cables go, you are dealing with a signal that may be hundreds of times stronger coming out of the amplifier than what is found in an interconnect. As such, losing a small percentage of signal is not as big of a deal. Think of the small line level signal coming out of a component ( source, preamp, etc.. ) as a dime and the much higher level signal coming out of the amp as a dollar in terms of volume or amplitude of signal. If one were to lose a "penny's worth" of resolution due to line losses, etc... with the interconnects, that would be a very noticeable percentage ( 10% ) of performance flushed down the drain. Using the same example, losing a "penny's worth" of resulution due to line losses from the speaker cable would result in only a 1% difference in resolution. A 1% loss or resolution is not a big deal compared to a 10% loss. This is especially true when you consider the fact that the 1% signal loss has already been amplified to maximum capacity since it has already made it past the amplifier whereas the 10% loss from the interconnects would be further amplified as it passed through the various gain stages of the signal chain. If the signal is lost or distorted PRIOR to amplification, any deleterious problems become magnified. The gain of the amplifier makes these losses / distortions even more noticeable. If we consider the fact that speaker cables are also typically MUCH heavier in gauge, which reduces series resistance to a minimum, line loss is not near as big of a deal. Since the series resistance is drastically reduced, voltage and current can flow far easier with less line loss incurred. As such, using cables with reduced line loss allows one to use longer lengths and still maintain good signal integrity. As far as RFI and EMI susceptability goes, it would be harder for these types of interference to "muscle" what is already a relatively strong signal coming out of the amplifier. While these outside influences may distort the signal between the amp and speakers, the effects produced can not be amplified any further since the signal chain has already travelled past the amp itself. The ONLY "valid" argument that one can muster for short speaker cables is that the amplifier "MIGHT" have slightly better control over the speaker. If one notices a HUGE improvement when using a shorter speaker cable over a longer speaker cable of similar electrical characteristics, the cables are simply too small of a gauge to begin with OR are of a poor design. Obviously, using greater quantities of a poorly designed ( or possibly "mismatched" ) product will produce noticeably worse results than if one were to minimize the effects of the poor design by using less of it. In plain language, 10' of junk ( or "less suitable" ) speaker cable will always sound worse than 4' of "less suitable" speaker cable. There is simply less "junk" to influence the sound within the system. Take a look at the FAQ section on the Empirical Audio Website for a technical breakdown. Steve has done a pretty good job of modeling a lot of basic info and putting it into graphs and charts. Bare in mind that he's making suggestions based on his experience and education as an EE, not just the fact that he is a cable manufacturer. The bottom line is that one should use the shortest cables possible ( within reason and common sense ) that one can get away with. This is true of interconnects, speaker cables and even power cords. If one must run long cables of any type, it becomes even more important to take such things as impedance, materials used and design geometries into consideration. Don't short-change ANY part of your system, as it is only as strong as its' weakest link. Sean > |
A few people around here (Sean, I think) have argued for long speaker cables. What are the technical arguments? |
Generally speaking, shorter speaker cables are preferable, so if you are faced with long runs (say, 15 feet or more), I'd advise using longer interconnects and shorter speaker cables. However, with the lengths you describe, it really won't be an important issue. |
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