psw 450 setup

mesquitehead

i purchased a psw450 and have a pair of sda1's and a harmon kardon avr 210 receiver. my question is what is the best connection for my bass signal? filtered or unfiltered? and how do i set up the phase on the sub. my hk has a sub out and i do have the obligatory monster cable(single rca). please help.right now i have the rca in the unfiltered jack.......i just dunno...oh ,i am also running rt800's in back with a nikko 100wpc amp and the front sda1's are running on a yamaha m-80.

Dr. Spec

Connecting a Monster cable from the LFE sub-out jack on the HK receiver to the UNFILTERED LFE sub-in jack on the PSW450 is fine.

In this case, your speaker size settings should either be "large" or "small" (personal preference - experiment), and your sub setting should be "yes" or "on". This will route all signals below a certain frequency to the sub via the LFE jack.

Your other option is speaker level connections, and in that case your speaker setting should be "large" and your sub setting should be "no" or "off". You will then need to manually select the crossover frequency to the mains with the PSW450 control on the back - I'd start around 100Hz and experiment to suit your personal preferences. This option offers more flexibility, but requires more speaker wire.

Spec

CHRIS

I'll try and give the best explination of phase I can. If one of your main speakers were connected backwards, POS to NEG (‘+’ & ‘-’) on speaker posts (red and black) & NEG to NEG (black to black or ‘-’ to ‘-’)on your receiver it would be out of phase with the other speakers. Most subs have a switch ‘0’ & ‘180’, just like switching speaker cable. Some have a dial for better blending. Witch ever you have go with what sounds best or right.

Dr. Spec

With respect to phase, if the sub is on the same wall as the mains, and the sub speaker cone is facing in the same direction as the mains, then you want the sub to be "in phase" with the mains. "In phase" means the subwoofer cone and the woofer cones on the mains are firing at the same time in the same direction and act together. This configuration will require your phase switch to be set at 0 degrees.

If you have your sub on the opposite wall, firing at the mains, you will want to set the phase switch to 180 degrees, so the sub cone essentially fires completely out of phase with the mains.

If you left the sub set at 0 degrees phase and placed it opposite the mains, the bass frequency wavelengths from the mains and the sub would be "fighting" each other and this will create standing waves at some frequencies, and wave cancellation at others, and overall a diminished and weird sounding bass response.

Of course the best set-up is to have a phase control that is variable from 0-180, so you can place the sub pretty much wherever you want and fire it in any direction and still be able to tune the phase response between the mains and the sub.

With that said, firing the sub along the same wall as the mains, in the same direction as the mains, and setting the phase switch at 0 degrees, is still the most popular, idiot-proof, and easiest set-up that will usually give you good results right out of the box.

You can always experiment with the phase switch to confirm some of this theoretical stuff........one setting will give you stronger and cleaner bass, and the other setting will give you weaker, muffled, and wimpy bass.

Spec

RuSsMaN

Not arguing, discussing.

What about bandpass and bottom firing subs? Also, the advice doesn't seem bad, but seems as if we assuming that the main speakers are reaching as low, or at least within the same octave as the sub. What if you run the mains through the sub?

I just have not heard this approach, as to setting the phase based on the position of the sub in the room. What I have always told people, is to simply listen, and have a friend/wife/dog throw (or adjust) the phase switch....One should sound better than the other.

Cheers,
Russ

Dr. Spec

Yeah, that's why I said in the last paragraph to simply experiment and see which sounds better.

Sure - side firing, bottom firing, running through the mains with obviously different frequencies coming from each - all these could fly in the face of my basic theory discussion. That's why I said the variable phase switch and your ears are really the best combo overall. All of those things, not to mention room configuration, can affect bass response and phase selection.

My recommendations came from personal experience, and a fundamental understanding of wave theory and wave behavior from a bunch of physics experiments in college - we sure had some fun creating all sorts of neat wave phenomenon with a variety of wave generators, including speakers. And many of our experiments did focus on phase considerations and how waves bounce around the room and cancel or boost each other not only at the same frequencies, but also at harmonics of those frequencies, which might explain at least one of your points. But a speaker designer I'm not, and I'm sure my explanation left something to be desired - one of the limitations of this format, I guess.

If you really want the low down on wave theory and phase, and how it relates to mains and subs, I'd check with SVS or HSU subs, or even talk to some Polk sub designers - these guys can explain it best.

Spec