More stereo sub help

[phheld]

Hi Pete and folks:

Very happy owner of two STF-1s. I was using a single in my two channel set up for some time and got the second a couple of months ago. I trying to optimize my set up. A couple of basic facts for context.

- I have a modern McIntosh preamp with 3 equivalent preamp out channels, all controlled by the master preamp volume control. Currently, I only using the main out to my vintage McIntosh power amp.

- Speakers are bi-wired B&W standmounters.

I had the dual subs wired in parallel to the mains as Pete described in another thread below, using the speaker level option. Parallel wire run to the right speaker and right terminals of the STF-1. Same on the left. The subs are of course just augmenting the mains, and I am manually tuning the crossover to do so (not hard with the B&Ws, sub friendly)

Questions:

1. Since the STFs both have RCA mono inputs, would it make any difference if I used a mono subwoofer cable from the 2nd right and left preamp channels to each of the subs (instead of the speaker level connections obviously). I figure I am now sending right channel info to the right sub and left channel info to the left sub, so replacing the speaker level wiring with line level wouldn't be any advantage. Am I right?

2. I have the phase switch in the same position for both subs - that is right isn't it?

3. I have the subs beside each of the main speakers. Many people put their dual subs together. Short of trying this out myself, is this likely to yield a benefit in bass performance?

Many thanks in advance for you input - Pau

[Pete_Hsu]

Hi phheld,

Performance wise there really shouldn't be any noticeable difference, unless one is using very thin and long speaker wire running to the subwoofer.

With two subwoofers, setting the phase is a two-step process. First try flipping the phase switch on one subwoofer to see if output increases or decreases. If output increases, then the two subwoofers are in phase with each other. After that, try inverting the phase on both subwoofers to see if you get a better transition between main speakers and subwoofers.

The benefit in putting two subwoofers together is mainly to maximize headroom and minimize cancellation between the two subs. The benefit in separating the two subwoofers and putting them near your left/right mains is possibly better integration with the mains, and potential to smooth out frequency response and allow higher crossover without localization.

Sincerely,

[phheld]

Pete thanks for the advice. I'll experiment a little with placement.

I'm using quality speaker-level cable (and not particularly long) so that angle is likely a non-starter.

Paul

[zanon]

How are you wiring up your subs again? Do you have wires going from the amp to the sub, then sub to your speakers?

Or do you have double wires going from your amp to your sub?

Or do you have wires going from your amp to you speakers, and then running wires from your speaker terminals to your sub (giving them high level input)? I think REL recommends you hook up subs this way, although I don't know what's special about their subs.

As Hsu says, if you put subs next to each other you're making a little line array. You'll get more volume as the waves will positively reenforce each other.

Personally, I would recommend having them separated, and then sweating over placement and phase so you don't get a suckout in your listening seat. But try it yourself!