Adding Subs to a 2 channel system. Wiring advise

It depends on the quality of the speaker cable.

Sorry, but I just can’t get behind your choice of sub when there are dedicated sub manufacturers that offer a lot more performance and value. For instance, the Rhythmic F12G is similar in size and the same price as the PSB 350 (including shipping) but goes down to 14Hz vs. 25Hz, has 23% more power, and weighs 50% more. Not even a comparison IMHO.
https://www.rythmikaudio.com/F12G.html

On the value side there’s the SVS SB1000 Pro that is smaller but still goes down lower to 20Hz, has 8% more power, and comes with an integration app so you can optimally integrate the subs from your listening chair with your phone (huge benefit). Plus, you can get TWO SB1000 Pros for less than ONE PSB 350 with free shipping.
https://www.svsound.com/products/sb-1000-pro-subwoofer

If you’re only going to use a high-level input I’d add REL to the list as well. Not sure why you’re looking at PSB, but I don’t see why it’d be a good choice given other much better options available. Hope this helps, and best of luck.

Thank You Soix! Appreciate the suggestion. I am very new and not as educated as I should be with the whole subject of subwoofers. The reason I was considering the PSB is for the High Level input and Output feature, so (if I'm understanding what I'm reading) this gives me the ability to completely separate the 80Hz and below signal to the subs, and pass through only above 80Hz to the mains. If I hook up a sub without the High Level Input and Output (say from the Pre-outs, etc) then am I not still sending the full signal (below 80Hz and above 80Hz) to the mains as well. I've been told there is a benefit to completely separating the signal between the sub and the mains? Or am I just not understanding it correctly? 

IMHO, you would save yourself a lot of effort if you bought a Vandersteen Sub 3.

This route isn't 'cheap', but it provides an easy and seamless way to integrate your speakers with the sub. It also allows you to dial in the sub with an equalizer-which no other sub manufacturer offers. (You do need to purchase the Vandy high pass filter). Though other manufacturers offer low and high pass filters, Vandersteen uses 1st order crossovers-which minimize time and phase distortions that occur using higher ordered crossovers.

If this doesn't work for you. There are other ways to 'skin the cat' 

Using other subs, the 'recommended' way is to use the speaker output to drive the sub. That way the signal is the same to the speaker and the sub, so you will be able to dial them in 'easier'. (You need a second set of (speaker) cables to connect to the sub, in addition to the set going to the speakers).

The other way is to use an aux preamp output to the subs. This works well, at least for me. (And, you will need a second set of cables (interconnects), to go from the preamp to the sub.

Mind you, this is dependent upon what the sub you choose offers in the way of connectivity.

Bob

If I hook up a sub without the High Level Input and Output (say from the Pre-outs, etc) then am I not still sending the full signal (below 80Hz and above 80Hz) to the mains as well. I’ve been told there is a benefit to completely separating the signal between the sub and the mains? Or am I just not understanding it correctly?

No, you pretty well nailed it. Which is better really depends on your tastes, room, and speakers. If you feel your speakers struggle with lower bass there may be a big benefit to using low-level inputs to the sub and cut off the low frequency to your speakers to 80Hz or preferably a bit lower depending on your speakers. Using this connection will also let you use a sub’s integration software, which is not a small consideration if you’re not experienced in seamlessly integrating subs or just don’t wanna mess with that involved process. Another benefit is that your amp will not be working as hard to drive your speakers as the sub will be handling all the power needs below 80Hz.  Of course the downside is that you will need to run the preamp signal thru the sub before going to your amp, but my opinion is that if you benefit from reducing the demands on your speakers and amp that’ll far outweigh any small signal denigration that might occur.  The high-level input will require your speakers to run full range and in theory make the subs a bit easier to integrate, but you won’t be able to use any integration software.  Both the Rhythmic and SVS subs offer both high- and low-level inputs so you can experiment and choose whichever works better for you in your situation (which is a big reason why I recommended them). If you want ultimate speed and performance I’d go with the Rythmics, but if you think having an app that’ll make integration relatively easy/painless (and integration is critical to getting good sub performance) and you don’t wanna fuss with researching a lot and devoting considerable time to successfully integrating subs the SVS subs might be a better fit. Do I think the Rhythmics will sound better? Yes. Do I think you’ll be thrilled with the sound you get from SVS? Yes. So it comes down to personal preferences/goals and convenience. That’s as best as I can sum it up, but I totally applaud you for going with two subs as that alone will put you head and shoulders over using just one sub. Goodonya!

BTW, just read @gdnrbob post and completely agree. Vandy recently introduced new subs, but their prior models are extremely good and are being offered used at almost absurdly low prices. If you can deal with their size and their unique crossover implementation this would hands down be your best performance value. Case in point, here’s one available now for only $550 — absurd, and prob won’t be long before another one comes available if you have the patience to wait. Definitely another option to consider as performance and integration with Vandy subs is absolutely top notch and worth some effort IMHO. FWIW.

https://www.usaudiomart.com/details/649909363-vandersteen-2wq-subwoofer/

@soix ,

Thanks for the positive feedback!

One of the main reasons I post is to help those who aren’t ’savvy’ to things audiophile. I was lucky to have been able to audition equipment during the ’80’s, when brick and mortar stores were easily accessed.

I know the value of being able to listen in a listening room. When I see a ’newbie’ post, I want to help guide them to making the best informed decision.-One that will minimize any future regrets.

The Vandy 2wq subs are a great buy. Like all Vandersteen products, they are built like tanks-Even 2w subs, now over 30 years old work as they should (how many REL or SVS subs can make that claim?).

B

Get a DSPeaker 8033 to hook up the subs and EQ them.

If the subs you get don’t have built-in integration software I agree with @kota1 that the 8033 is a very good option as is its bigger brother the Anti-Mode 2.  Will save you a ton of work/headaches and probably sound better in the end. 

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.