Subwoofer connection


#1

Paul made mention of hooking up his sub using speaker cables rather than the LFE which I also plan to do (even have the same sub he originally had). I just wonder if there is a difference on how to hook up-

  1. speaker cables go from main 2 channel speakers themselves to the sub, or

  2. speaker cables go from the amplifier outputs to the sub

I see no difference but just want to confirm. My preferred choice is 2)

thanks

Mike (owner of the system featured in Copper #7)


#2

There are three speaker level wiring options that I can think of.

  1. Cables from Amp to Speakers, then to Sub.

  2. Cables from Amp to Sub, then to Speakers.

  3. Cables from Amp to Speakers, and separate cables from Amp to Sub.

While I am not currently running a sub, option 3 would be my preference as I feel it would have the least impact on the signal going to the speakers and you could use an entirely different cable, perhaps much cheaper, for the connection to the sub. Putting both loads on the amplifier terminals gives the amp a better chance of fully controlling the load.

My second choice would be option 1. This would give the same signal path to the speakers, but put the load of the connection to the sub at the speaker terminals, possibly degrading the signal quality at the speaker terminals, even if only slightly.

Option 2 would be my last choice, as in almost all cases it would be the longest cable path to the speakers (the greatest and most critical load) as well as an additional set of connectors to possibly degrade the quality of the connection.

Just the thoughts of one techie… :slight_smile:

J.P.


#3

Great answer, thanks!

mike


#4

Huh. You would think that a second set of wires from the amp to the sub would add additional capacitance on the amp terminal output and would affect the sound a bit. I run my sub from the output of the preamp, but I suppose that’s an additional load on the preamp, which, in turn, sees another impedance on its output terminals plus an additional capacitive load on the preamp output.

Don’t know. Let us know how it turns out.


#5

Yes, the second set of wires on the amp’s output would add a reactive load. I would much rather have this right at the amp’s output than added to the end of a set of speaker cables. Having the added load right at the amp’s output gives it a better opportunity to control any effects of the additional loading through its (hopefully) low output impedance.

I have read arguments both ways about driving a subwoofer from the amp’s output and from the preamp. Both have advantages and disadvantages, it is up to the user to determine which works best in his system.

J.P.


#6

JP, it may also depend on the preamp’s ability to drive the impedances. I know in my case with the AudioResearch LS26 the tube output is coupled via one capacitor to the output terminals, so if there’s a low input impedance on the two amp inputs (amp and sub) then it may not be sourced by the preamp properly. I’d think the BHK preamp would have no problem with this as it has the solid state output. I guess I’ll have to order the BHK and find out . . . .


#7

Absolutely. As with all things audiophile, equipment synergy is a part of the equation. While common with tube sources, high output impedance and poor line drive can afflict solid state equipment too. This ability or inability to drive multiple loads could limit some to having to use a speaker level input on the sub in order to get best results in their system.

Always back to the old hack: YMMV.

J.P.