Adding Subs to a 2 channel system. Wiring advise

With your amplifier and speakers level of quality I’d run everything full range.

The PSB 350 is invoking low pass as a result of its limited frequency response, -3dB @ 25 Hz and drops significantly to -10dB @ 20HZ. These are only slightly lower than most speaker low frequency specifications.

Using the Luxman Pre RCA outputs bypasses the 509’s amplifier and sends all the source signal to the PSB low level RCA inputs (the PSB preferred method).

Unusual to me, the PSB low level RCA outputs are fixed to process an output 12dB/ Octave below 80Hz. Typically the low level output are used to daisy chain subwoofers. PSB suggests Y connectors at the Pre outputs instead of including a simple switch at the subs RCA outputs. Along with its limited low frequency response and the Y connector connectivity schemes suggests to me a more mid consumer subwoofer, still, better than no subwoofer at all.

High or speaker level connectivity is included by many subwoofers as a convenience for systems that lack Pre Outputs. Your Luxman has two pair.

Consider a manufacture that offers a trial period and pays for shipping both ways.

Vandersteen are fabulous products. They are not the only subwoofer to include onboard frequency and filter equalization.

In the 'no free lunch' category, DSP has limitations. You can introduce time/phase delays/inconsistencies.

YMMV.

B

Hi Mr. 88

To answer or question more directly, my opinion is that the amount of signal degradation you would hear from your mains with the wiring scheme you have stated should be imperceptible. If you do hear a difference from your Focals,  I believe you should be able to connect two pairs of speaker cables to each of the Luxman’s outputs and run one cable to a Focal and one to a sub bypassing the pass through circuitry in the sub.

The bigger issue to me is your selected crossover point. Crossing over at 80 Hz creates a lot of frequency overlap from two separate sources which should result in quite noticeable muddy bass, that I believe would be more than just a little difficult to fix. It is generally recommended in these situations when you are not using a high pass filter, such as a miniDSP in your integration, to set the subs crossover point at approximately the main speakers 6db down point, which in your case would be 31 Hz, which depending on what type of music you listen to, could leave your subs with very little to do.

You might find the below white paper useful.

https://www.soundoctor.com/whitepapers/subs.htm

Thank You very much!! Great Info, and yes indeed I will set the crossover much lower as you said. Your opinion of the SVS 2000 Pro? Thinking a set of these may be the easiest to "tune" with the App. 

Good Day Mr. 88

I apologize for the slow response. I do not frequent this site much so if you have a future question directed to me, it would be best to pm me.

In my opinion SVS makes a good product at a decent price point. I have two SVS SB4000’s in my system along with a Rythmik and a REL. Whether the SVS 2000 Pro is the best for you will depend on what you listen to and how loud, and to some extent, room size. For example in my case I listen to a lot of bass driven music and I like a strong kick drum, my room is small at 14 x 10 x 9 and I typically drive my mains to 90 db crossed over at 173 Hz. (Subs handle everything below 173 Hz.) Since I like a solid kick and to have it at a balanced or equal sounding level to the mains or maybe even slightly louder I need to drive my subs to 112 db, so even though I have a small room I need large subs.