Subwoofer - Line level or Speaker Level

[Memoryerror]

My subwoofers havr both speaker level and line level (rca) inputs and outputs. Would it be better to connect them between my DX7s and my amplifier with rca cables or between my amplifier and my speakers with speaker cables?

 

[DonH56]

Line level is usually easier to deal with and has lower noise since you do not have to attenuate the speaker level back to line level to drive the subwoofer's internal amplifier. Line level also means the signal to the subs is not affected by the interaction of the amplifier's output impedance with the speaker's input impedance, and there are fewer gain stages to add noise and distortion.

IME/IMO - Don

 

[trl]

Worth mentioning that some people might have EQ on their main speakers, also a bit of Loudness contour as well, depending on the volume level and REW in-room measurements. So, Line-level could be a better choice for most of us.

As for the increased THD and possible inability of amplifier's output stage to drive some speakers, that's a proven fact, especially with speakers that have an output impedance between 3 and 20 Ohms (despite the 4...8 Ohms message from the back of the speakers). Usually a preamp has a THD with 10 to 100 times lower that the output stage (@50% of max. power) and this can be easily verified comparing manufacturer's specs.

 

[amirm]

Line level. The notion of using speaker outs is to impart the same tonality as the main amplifier to the sub which is complete myth.

 

[trl]

AFAIK speakers-out input plugs is most of the time implemented on not-very-expensive subwoofers and exists only because some amplifiers have no sub-out RCA plug. It happened to me with Pioneer A-209R amplifier that has no sub-out circuit.

Also, if there's only one RCA sub-out and I want to connect two subs (Left & Right), then using speakers-out input from the subwoofers might help me out here, especially if soundstage is important for me and I don't want to use RCA-Y-plug to divide the only RCA-sub-out to both subs. I know that usually low-end is not involved into the final soundstage, but what if some people has the high-pass filter above 100 Hz?

 

[Soniclife]

The notion of using speaker outs is to impart the same tonality as the main amplifier to the sub which is complete myth.

Thanks for clearing that up, I've never followed the logic of how that was meant to work.

 

[Deleted member 2944]

Line level. The notion of using speaker outs is to impart the same tonality as the main amplifier to the sub which is complete myth.

Well, actually you do impart the same tonality of the main amplifier to the sub(s). Whether that's a good thing or not in a particular application is unknown. The subs limited frequency range might not make that tonality audible, but it's still there.

Some users don't have a separate preamp/amp scheme and possibly not a volume-controlled line-level output available. So, the high-level input might be the only option.
The OP here does not have that issue though.

Dave.