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Analog cable vs. Digital coax


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8 replies to this topic

#1 of 9 OFFLINE   john doran

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Posted January 31 2002 - 11:45 AM

I'm looking for a little help here: Is it better/the same/worse to use digital coaxial cable to hook up a subwoofer rather than subwoofer cable? I have asked numerous individuals (interconnect sellers as well as speaker manufacturers) and seem to be unable to get a consistent response; i have heard both that coax is better, and that subwoofer cable is better (although never that it doesn't matter...). Are there any insights?
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#2 of 9 OFFLINE   Mark Rich

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Posted January 31 2002 - 12:02 PM

Either will work. Coax cable is coax cable. The digital should be 75 ohms while the subwoofer (analog audio) doesnt have to be. Some cable makers use same cables for analog,digital and video. In that case it wouldnt matter. Others use specific cables for each application based on the cables performance in its role. Which will work better will depend on the type of cable used by the manufacturer.
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#3 of 9 OFFLINE   Bob McElfresh

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Posted January 31 2002 - 03:49 PM

Hello John. Welcome to HTF! You do know that a subwoofer cable, a audio interconnect, your CATV cable, your digital-coaxial cable are all COAXIAL in construction? Coaxial cable can be found with the following different impedences: 50/75/110/300 ohms. The "rule" is: - All Video cables are made with 75 ohm coax - All coaxial-digital cables are made with 75 ohm coax. Audio interconnects can be made with any of the different impedences, including the subwoofer cable. (The low-frequency audio signals are not picky about cable-impedence. This is why you are not getting a straight answer - because it typically does not matter.) So a coaxial-digital cable (must be 75 ohm coax) will make a fine subwoofer cable. Issue unique to subwoofer cables: Subwoofers seem to be sensitive to how tight the RCA plug is. I believe this is why people sometimes buy a expensive cable with the word "subwoofer cable" on the package and hear a difference. The new cable has a tighter RCA plug. So with this in mind, I'll change my recomendation to include: "A coaxial-digital cable will make a fine subwoofer cable, as long as it has snug-fitting RCA plugs". Hope this helps.

#4 of 9 OFFLINE   Mark Rich

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Posted January 31 2002 - 04:10 PM

Bob, Curious why you keeping recomending a "snug" fitting RCA connector as being the most important factor in a sub cable? Following that logic then I guess the Monster grip of death connectors must make for the best sub cables? I find the monster sub cables be be some of the worse I've tried. Bloated best discribes them. I think the quality of the connector (materials used in its construction) have far more of a bearing on the cables performance than its tightness. I know a lot of people here say when it comes to sub cables coax is coax but I have found that its not the case. Providing you are of the opinion that cables do make a difference then sub cables are an area open to improvemnt. Electrical performance aside the best cable I have tried is a cable that uses Teflon as the insulation. I share Jon Rische's recomendation of the Belden 89259 coax cable for sub use. Big improvemnt over Monster,Canare and other Belden cables.
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#5 of 9 OFFLINE   john doran

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Posted January 31 2002 - 04:21 PM

Thanks a lot for the help, guys (and thanks for the welcome, Bob). I ended up going with the Rhino Subwoofer cable (Belden 89259); I hope it's better than the Monster cable that came with my stuff, which feels rather cheap and insubstantial, and which I hope is (one of; the major) contributor to the sometimes bloated bass I'm experiencing. By the by, the connectors on my Monster cable are anything but grip-of-death tight. Now for some advice on room-modes and speaker placement...
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#6 of 9 OFFLINE   Mark Rich

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Posted January 31 2002 - 04:37 PM

John, Which monster sub cable have you been using? I tried the death grip connectors (the turbine ones that come with the 400MKII cables) with Canare cables (G6). Those suckers do have the death grip! Almost wrecked my Rcvr and sub getting them off. What sub are you using?
"None are so hopelessly enslaved as those who falsely believe they are free."

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#7 of 9 OFFLINE   Bob McElfresh

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Posted January 31 2002 - 05:33 PM

Mark: I'd appreciate some feedback on my conclusion. Here is my reasoning: In the early days of SVS, someone ordered one and was disapointed in the sound. He claimed his $300 Energy sub had more authority. He was using an inexpensive Radio Shack grade cable (which the SVS guys say is just fine). After working with him, Tom/Ron concluded his plugs, with a loose fit, did not work. They rushed him out some new plugs, but the customer went to his "parts" box and found a similar cable, but with tighter plugs and it made a world of difference. On my own sub, I can start a bass-heavy scene and slowly pull the plug off the connector. The sound changes as each incrimental part of the plug moves. (This does not seem to happen with my CATV coax or my video plugs - just getting a good touch seems to give fixed/good signal transfer.) So there IS either a surface-area or tightness issue with the connector. (hard to separate) I do know about the "Skin Effect" - that signals on a wire travel on the surface and not the center. But I also know that various issues with higher frequence signals, dont apply at lower frequencies. (Kind of like how capacitance and impedence do different things). I do remember a physics classes where there was discussion about how far down into a circuit-trace a signal would go being frequency-dependent. Basically - the lower the frequency, the lower into the crystal lattice the electrons would flow. (We were talking about dopped silicon, but the model should be valid for Copper). So the theory seems to indicate that a low-frequency signal does not entirely travel on the surface. A better connection (more surface/pressure) on the plug would give you a better transfer. The last bit of support comes from pondering this question: Why does Monster have grip-of-death connectors? You would think this was a liability. If they break the connectors off on your equipment, people will get mad and give them a bad reputation. So why? Perhaps because they learned a tighter plug sounds better? I know we have ignored the coax here. And we do know that Capacitance is a low-frequency effect for a wire. But none of the wire vendors include 1/2/10/20 hz frequency response for any of their coax. Why not? Could it be because above 1 or 2 hz - it does not matter? My training/education all agree with this. None of this is scientific/conclusive/definitive. But... it feels like there is some truth to this. I welcome your thoughts/discussion. This is why I caution that subs are sensitive to a nice, tight-fitting RCA plug.

#8 of 9 OFFLINE   Mark Rich

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Posted January 31 2002 - 05:51 PM

Interesting theory. My findings (amateur testing) just dont match this however. I find no difference between a canare connector (which is not the tightest) and the Monster death grip plug. I believe Bettercables uses the same connectors for their sub cables which they provide to SVS (if my memory serves me). Most of the cable guru's at cable asylum seem to agree that with sub cables the plug makes very little difference to the cables performance. I did find a very slight improvement (barely noticeable) with connector changes on full range analog audio cables (using Cardas plugs) but not with the sub IC. The cable changes were more obvious. Oh well guess this is why we have opinions and open forums. Your input and common sense suggestions is greatly appreciated. Look forward to reading more of your posts.
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#9 of 9 OFFLINE   john doran

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Posted January 31 2002 - 06:35 PM

Mark, The Monster cable is Interlink 201 SW HT - the store that sold me the equipment gave me what seems like yards of it. So that, coupled with the rather slight build of the wire and the fact that I can't actually find it on the Monster Cable web-site leads me to believe that it can't be all that hot. Plus the connectors aren't very tight. Anyway, none of that could mean anything, I suppose - I am, after all, a rank amateur and johnny-come-lately to the Home Theater world. But, thanks to exchanges like those between yourself and Bob, I'm learning. And the subs I'm using are the ones in the Def Tech bp2000tl's. I hope one day to pick up either a couple of SV CS Ultra's or a Velo HGS 18, too (I'm a bit of a bass junky), even though the subs in the Def Techs perform astonishingly well for me (I can imagine louder bass at the same frequencies, but certainly not faster or cleaner bass). Anyway, Thanks again. John
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