Wires and Cables

[Retread]

I thought I saw a thread on this site about speaker wires and cables, but my searches turn up nothing.

In any case, here are my questions, in the context of having a new 110 Watt per channel surround sound receiver and the impending arrival of a VTS-3R and Ventriloquist system:

1. As an RCDD electrical engineer with a Ph.D., I have a great deal of skepticism about the virtues of special cables to hook up speakers. Is there any real benefit from special cables over ordinary (for instance 12-guage) zip cord?

2. I'm going to have a run of about 40 cable-feet from my amp to my VTS-3R. Since that will be a high-impedance connection, anything special needed? For instance, is twist needed?

3. I'll have a run of about 30 cable-feet, between the amp and the rear Ventriloquist speakers. Other than having large cross-section copper (e.g., 12-guage) , anything special needed?

4. I see (e.g., Monster Cable) references to tight twist to avoid pickup from other sources. Tight twist is clearly of importance in low signal, high frequency (e.g., Fast Ethernet) applications, but is pickup a problem in high-power, relatively low frequency, low-impedance applications such a connecting Ventriloquist speakers?

5. I saw a reference somewhere to "oxygen free" cables. What are they on about?

I'll spend the money to get the right cables, but don't want to fall victim to "golden ears" scams.

[Sorny]

1. No. Fat copper is all you need, just as your EE training tells you. I happen to like 12 gauge zip cord myself...

2. I'd use some RG-6 QS for my subwoofer cable. Crimp-on phono (RCA) plugs and RG-6QS makes for ultra cheap subwoofer interconnects. At the frequencies used, and the distance required, RG-6QS is about perfect. If you have some RG-59 laying around instead, use that as it is not quite as stiff as RG-6.

3. No, nothing special required.

4. Monster is blowing smoke. They also need to learn that skin effect is not present at audio frequencies...

5. Pay no heed to Oxygen free. 'Tis a marketing term.

Since you asked for honest opinions, I'm giving mine. People may disagree, but EE principles tell me all I need to know about cable. I'll start to believe the cable-hype when a single DBT shows an audible difference between wires of sufficient gauge. Since no cable maker is foolish enough to try a DBT, I guess I'll be a skeptic my whole life... Oh well. :D

I use some Monster cable interconnects, some Radio Shack Gold Series interconnects, and some Acoustic Research interconnects. I've found that there are no differences in the video/sound when switching from $100/meter Monster interconnects vs. $10/meter Radio Shack interconnects. I use the Monster cables and cheap-o Radio Shack cables interchangeably. Good prices on decent cables can be found at Parts Express (www.partsexpress.com). Look for the Dayton Audio brand cables. They also have great prices on “Sound King” 12 gauge in-wall speaker wire. If you wanted to make your own cables, PE has the bulk supplies you’d need to make your own boutique cables if you so choose.

Sorny

[Retread]

I infer from your recommendation to use coax that low frequency pickup is considered a problem for the connection to the subwoofer.

I have a good bit of extra Cat5 Fast Ethernet cable available. Cat5 is tight-twisted and may be better for low frequency electromagnetic rejection than coax. If I remember correctly, the VTF-3R has a 10K input impedance, so current should not be an issue.

What do you think?

[cdinsmore]

Retread,

I read a publication called The Audio Critic. They have an extemely brilliant EE with a PHD on their staff by the name of David Rich. According to The Audio Critic the high price speaker and interconnect industry is a shameless fraud. In double blind ABX tests, no one has ever been able to discern the difference between reasonably priced interconnects/speaker cable and cost no object designs.

[Sorny]

It isn't so much low frequency pickup that is a problem, IMHO, but rather the possibility for the interconnect to become an antenna. I suggest using coax because of the better shielding typically found on coax. I'm unsure how the cat-5 would work as an interconnect. Ideally, you'd want 75Ohm cable for the subwoofer interconnect. RG-6 fits 75 Ohms and fits as it is well shielded.

Sorny

[Retread]

I'm not sure what you mean about the subwoofer connection becoming an "antenna." Antennas will both radiate and receive (pickup). I can't conceive of a problem that might be caused by a high impedance line at subwoofer frequencies radiating. On the other hand, a high impedance line will definitely pick up 60 Hz from power lines in the area. Such a line will also pick up all kinds of other trash floating around the environment.

Speaking of impedance. Coaxial cables typically come in 50-ohm and 75-ohm varieties. The connection between the receiver and the subwoofer is 10K-ohms. By the Maximum Power Transfer Law, all components in a system should be of the same impedance. Also, in a high-frequency transmission line, the source/sink and transmission line characteristic impedance must be matched or you get reflections. Neither of these issues exist in the current case, so I don't think the impedance of the connection between the receiver and the subwoofer matters. Signal loss through capacitance is a major issue in high frequency lines, and coax is good on that, but at subwoofer frequencies, I don't think capacitance losses are a consideration.

One way to minimize pickup in 2-wire lines is to twist the wires. This results in both wires picking up the same signal and cancelling out. The tighter the twist, the better the rejection of external signals. Cat5 Ethernet cables have a very tight twist, specifically so as to reduce all kinds of pickup.

Sorting through various advice from various sources, I'm inclined to use twisted shielded "audio" cable. This is cable with two twisted wires inside a braided shield. Black wire to the RCA shell on both ends, shield to the RCA shell on one end.

[Sasha_G]

Our official company line is that for longer runs, you should use thicker gagues for speaker wire.

Under 10 feet, 16 AWG or thicker
10-25 feet, 14 AWG or thicker
25-50 feet 12 AWG or thicker

Banana plugs have no real sonic benefit, but they tend to provide a more reliable connection after disconnecting and reconnecting. They provide a positive, springy connection. There are often times when a speaker needs to be moved, and they just make life a little easier.

For interconnect, you can use ours, joined with an adapter, our make your own. Any decent shielded cable will be fine. Belden interconnect cables are used in many recording studios and are inexpensive. Again, I prefer springy connectors that grab onto the plug. Also, a corrosion resistant surface like gold is nice.

Although we side towards the skeptical side of the cable arguments, I've heard of a few studies where the visual aspects of an audio system overwhelm the auditory sense. That is, a nice looking system will tend to sound better.

I guess the lesson from those studies is that if you are not going to hide a cable in the wall, might as well get a nice looking cable. ;)The nice thing is, beauty is a subjective thing. For many, thankfully, the functional aspects underneath a braid covering or thick tube is more aesthetic than the covering itself. And if you want the braid, you can get them at PartsExpress.com.