Sub to receiver wiring

Belling

I am new to this forum and new to Polk speakers. I purchased an rm6700 system. It came with a psw303 sub. The instructions state that the sub should be hooked up with speaker wire from the receiver main speaker terminals to the sub rather than using a sub cable. I did it that way, but I'm wondering if that is the way to get the best sound. The sub seams a little weak. I realize that it is a smaller sub and the room is fairly big (13x22 which opens into the kitchen dining area thus increasing the size). I want both better sound and more volume from the sub. Should I switch to sub cable instead of speaker wire? Is there anything else that I can do?

PolkThug

Place sub in corner of room for maximum effect. Use a sub cable, on sub set volume knob to 12-1 o'clock position, phase = 0. On receiver, set sub yes/on, crossover at 80-100, all other speakers set to small. Use the sub out level on the reciever to adjust to your tastes.

Regards,
PolkThug

silverghost

PT -

Just curious . . . you seemed confident about setting phase on the sub to "0." I use "0" on my Titanic sub, but I'm not convinced that I hear any real difference when I switch to "180," or anywhere in between (the control is variable). Short of using an SPL meter, how do I know for sure which setting is best? For the record, it sits in a corner on the opposite side of the room from the mains.

I also set the sub's volume at 9:00, with max gain from the receiver (gain on the mains is also max'd). Should I back off the gain and turn up the sub volume?

PolkThug

Hi silverghost,

When you set the phase to 180, the sub actually moves in the opposite direction when the bass hits. IMO you get less bass when this happens. I haven't really seen any examples in HT where you benefit from 180. I have seen in car applications, where 2 subs are directly facing each other and one is reversed.

Should I back off the gain and turn up the sub volume?
Yes. But don't take my word for it, try for yourself. You probably shouldn't have all of your gains maxed. You really need an SPL meter and a test tone to balance it.

Regards,
PolkThug

silverghost

This newb offers thanks for the phase advice.

I'll try the sub with vol@12:00, lower the gain, then play with gain on the other speaks to match.

Yeah, sounds like a plan to me!

braveheart

Try lowering the volume level (receiver) to the sub and then use the volume dial on the sub.. It works nice for me this way. I have learned that the signal is cleaner(less distorted) when sent to the sub this way.

silverghost

Originally posted by braveheart
Try lowering the volume level (receiver) to the sub and then use the volume dial on the sub.. It works nice for me this way. I have learned that the signal is cleaner(less distorted) when sent to the sub this way.

Thanks -

Just did that a coupla hours ago, and it does sound a lot cleaner. On my receiver's scale of -20 to 0, I set the sub at -15 and turned the sub's vol control to 11:00 or so. Much tighter!

Stefanie

I just set up my system this past weekend and I am working on getting it set up right. I have the following:

Hitachi 65T500
RTi8's front
CSi5 center
FXi3's surround
PSW505 sub

Yamaha rx-v1400

The sub is hooked up to the receiver thru the LFE in (unfiltered). I assume that I am bypassing the xover on the sub. I have all the speakers set to small and swfr on and set at 80hz. I will use the spl meter next week when I have some time. I have noticed that in order to get some real bass I have to have the volume knob at at least 1 oclock on the dial. How do I lower the gain on the receiver?

Tour2ma

Damn, are all the newbies required to enter through the sub area now? Welcome Belling... My third welcome in a row...

The 303 is not that big of a sub. With the size of your size room alone (~2300 cu ft) it probably gpoing to struggle, but add the opening to more space and... well, I don't like the odds. PT's advice will give your 303 the best shot of satisfying you.

Another cool way to find your optimum sub spot is to put it where you nomally sit to listen. Then walk/ crawl around the wall placement areas available and see where it sounds best. When you swap places, the same sound or close to it should be there waiting for you.

SG,
Glad you're liking your bass better now. You never want to max any output settings out. Pre-amps can clip just as amps can. Where you have two controls moderation in both should yield the cleanest signal at the desired level.

As for the phase question. Sometimes you need to reverse polarity of a sub to blend it better with the mains in the crossover region where both the sub and mains are producing the same frequencies. It's a function of the difference in distances from the listener. Many subs have a 0/ 180 switch. Some have a 0 to 180 dial which is better as it gives you more flexibility.

Get someone to flip the switch while listening and see if a difference is produced. Use moderate volume or pause the source momentarily while they flip the switch.

Stefanie,
AVR's vary in their basss management and some have a set sub out level. Consult your manual is the best advice I can offer. If it doesn't address it post a new thread here or in the Electronics sections with the model of your AVR in the title to attract other owners. That said IMO a 1 o'clock setting is not that extreme that I'd worry about it.

And yes, you're bypassing the subs x-over by using the LFE in. All frequency management is in your AVR's hands.

braveheart

Stef,
When I had my speakers all set to small and the receiver handled the crossover, I had the crossover on the sub turned up all the way (120-150). My SONY receiver has a default crossover of 120hz. when speakers are on small. This sounded good to me.
Like Tour2ma so correctly stated, you must find out what your receiver's crossover is and go from there. Turning down the volume of the sub at the receiver first is a good first move, then up the crossver at the sub, adjust the gain at sub to something with bass you know well. Its a good start. Take care.