Subwoofer cable?

[laidick]

Some people say subwoofer should use 75ohm coaxial cable, some cable claim themselves are specialized for subwoofer.

What actually the difference between a normal RCA cable, say Canare 4E6S, vs a 75ohm cable, for subwoofer usage?

Does distance matter in this consideration? Since usually we put subwoofer somewhere in the room which may far away from your device.

 

[MZKM]

It is claimed that subwoofer cables have better shielding.

MediaBridge on Amazon sells subwoofer cables and RCA (well, digital coax) cables, which look identical except the color on the connectors. It would be interesting to see these measured.

 

[laidick]

It is claimed that subwoofer cables have better shielding.

MediaBridge on Amazon sells subwoofer cables and RCA (well, digital coax) cables, which look identical except the color on the connectors. It would be interesting to see these measured.

Yeah.
I would like to see how those cable measures, especially in long diatance, and how it shields and isolate interference from outside.

 

[mansr]

Shielding might be more important for subwoofers since the 50/60 Hz mains hum is right in the middle of their operating range. Other than that, there's no difference. Any decent quality coax will be just fine. If a cable marketed as intended for subwoofer use, it could be simply because it's a single coax rather than a left/right pair.

 

[Vincent Kars]

75ohm coaxial cable

That is a requirement for SPDIF but works as well with analog signals.

 

[iLoveCats]

MediaBridge on Amazon sells subwoofer cables and RCA (well, digital coax) cables, which look identical except the color on the connectors. It would be interesting to see these measured.

They have the picofarad measurement somewhere on their non amazon site. Its like 17pf/1000ft. Its pretty low. The bluejeans cables are like 13pf. I know there was an immediate impact on my record player when I used meadiabridge ultra RCA's over what came with it (project generic phono cable).

 

[MediumRare]

What’s the difference in running line out to a powered sub vs. using high level output w speaker wire - still to a powered sub? I heard the second way is better for long runs as a higher level signal.

 

[MZKM]

They have the picofarad measurement somewhere on their non amazon site. Its like 17pf/1000ft. Its pretty low. The bluejeans cables are like 13pf. I know there was an immediate impact on my record player when I used meadiabridge ultra RCA's over what came with it (project generic phono cable).

I just checked their 3 RCA models: Stereo RCA Cable, Subwoofer Cable, and Digital Audio Cable.

All state the exact same specs, 75ohm and 56.5pF/m so ~18.5pF/ft.

Blue Jeans has:
Belden 1694A/1695A: 16.2pF/ft
Belden 1505F: 17pF/1ft
BJ LC-1: 12.2pF/ft
Canare LV-77S: 22pF/ft

 

[MZKM]

What’s the difference in running line out to a powered sub vs. using high level output w speaker wire - still to a powered sub? I heard the second way is better for long runs as a higher level signal.

Then the subwoofer is doing the HPF crossover, which likely is an after thought and lower quality than what an AVR/integrated can do, and is also usually fixed at 80Hz (the crossover knob gets disabled).

 

[SIY]

They have the picofarad measurement somewhere on their non amazon site. Its like 17pf/1000ft. Its pretty low. The bluejeans cables are like 13pf. I know there was an immediate impact on my record player when I used meadiabridge ultra RCA's over what came with it (project generic phono cable).

Slip some decimal points?

 

[SIY]

I just checked their 3 RCA models: Stereo RCA Cable, Subwoofer Cable, and Digital Audio Cable.

All state the exact same specs, 75ohm and 56.5pF/m so ~0.185pF/1000ft.

Slip some decimal points? Or divide instead of multiply?

1000 ft = 300 meters (about), so C = 300*56.5 = 17000 (about) pF

 

[mansr]

Or divide instead of multiply?

Looks like it. 56.5 / 304.8 = 0.185.

 

[MZKM]

Slip some decimal points? Or divide instead of multiply?

1000 ft = 300 meters (about), so C = 300*56.5 = 17000 (about) pF

Whoops, shifted the decimals the wrong way. I blame @iLoveCats for giving me the wrong initial value.

 

[SIY]

Whoops, shifted the decimals the wrong way. I blame @iLoveCats for giving me the wrong initial value.

I blame the need for more morning coffee.

 

[Bear123]

I use Blue Jeans Cable LC1 subwoofer cables. What I think is important to note is that not only are they likely one of the very best quality cables made especially in terms of shielding/noise reduction, but the quality of termination/connection is exceptional and rather unique.

I've suggested these to many many folks who were getting hum/noise issues with cheaper Amazon cables, and they often remedy the issue. Honestly a fairly inexpensive investment to eliminate the chance of noise and hum, especially if you end up with higher sensitivity subwoofers.

They are also very flexible which can help with routing.

One nice feature imo that is not offered would be the option to terminate one end with a 90 degree.

 

[MediumRare]

Then the subwoofer is doing the HPF crossover, which likely is an after thought and lower quality than what an AVR/integrated can do, and is also usually fixed at 80Hz (the crossover knob gets disabled).

If I understand you correctly, you’re supporting the concept that high level is better. It also ensures the same signal is going to the sub and mains which should help integration.

 

[Speedskater]

For any long RCA analog interconnect, it's not about 75 Ohm Radio Frequency Characteristic Impedance, it's not about total capacitance and it's not about shielding per say.
It's about low end-to-end resistance of the shield (which requires a heavy braided shield). This is to reduce Common Impedance Coupling noise (hum & buzz).
Blue Jeans has:
Belden 1694A/1695A: 2.8 Ohm/1000ft
Belden 1505F: 2.4 Ohm/1000ft
BJ LC-1: 1.7 Ohm/1000ft
Canare LV-77S:<1.8 Ohm/1000ft

 

[DonH56]

If I understand you correctly, you’re supporting the concept that high level is better. It also ensures the same signal is going to the sub and mains which should help integration.

I have read that statement (same signal = easier integration) many times but have never understood why that should be so. I have never found that to be the case for me or the subs I have set up for friends since sub/mains position, room effects (modes, SBIR), filter and speaker crossover phase, amplifier and driver characteristics, speaker cabinet design (e.g. vented/sealed), etc. play a bigger role than having the same signal to both. And in general I have no desire to drive my mains full-range. What is the reasoning behind the desire to send the same (electrical) signal to both?

 

[rccarguy]

Sounds like a page from the rel manual

 

[iLoveCats]

Whoops, shifted the decimals the wrong way. I blame @iLoveCats for giving me the wrong initial value.

lol I'm somewhere in the ball park. The point was its low capacitance for the cost of the cable.