is this the proper way to hook my sub up to my receiver?

[TheWart]

All,

I recently ordered a Velodyne DEQ-12R to go with my two Martin Logan Motion 12 speakers (I know, I know, just 2.1 but what can I say). The place was out of stock of the 12R so they sent the 15R at no added cost. I was like sweet, more bass...haha. This thing is huge, but luckily I do not own a lot of furniture so it has a nice corner in which it sits.

Anyway, my question is how best to hook it up to my receiver. I have a 'regular' 20 foot subwoofer cable and then a Y adapter as the Velodyne has two inputs. However, what I didn't know before I hooked it up yesterday was that my Onkyo also has two subwoofer "pre-outs" or whatever. I am currently just using one, but would it be better if I get another Y adapter and use both?

Also, what frequency cutoff would you guys recommend given my Martin Logan front speakers. I am so far from an expert in this field, but I was thinking maybe 80hz? As in anything below that is sent to the subwoofer (at least that is how I thought it works)...

Thanks in advance for any help!

 

[Howard]

No. Just one sub pre-out to one of the inputs is fine.

Ideal crossover frequency depends on where the sub is located.

 

[TheWart]

No. Just one sub pre-out to one of the inputs is fine.

Ideal crossover frequency depends on where the sub is located.

Thanks for the info.

Here is a rough diagram of my layout:

TV
|
| 6ft
couch
|subwoofer about one foot behind couch in the corner.

On either side of the TV are the Motion 12s.

The room itself is open, and behind the couch area is the "dining room." It is just a standard 2BR apartment so not like this is in a media room or anything.

 

[kornphlake]

FYI, a corner is often not the best location for a sub, google corner loading for more info.

XO frequency not really something one can just recommend over the internet, you'll have to experiment and decide which sounds best to you. Generally 60-80hz would be best if your mains can handle it, if you go to 100hz or higher you may be able to localize the sub.

 

[Howard]

FYI, a corner is often not the best location for a sub, google corner loading for more info.

XO frequency not really something one can just recommend over the internet, you'll have to experiment and decide which sounds best to you. Generally 60-80hz would be best if your mains can handle it, if you go to 100hz or higher you may be able to localize the sub.

On the other hand, if his sub was close to the TV between the mains, it would be much harder to localize.

 

[gorb]

The crossover should be set at 1.5-2x the F3 of your speakers (40Hz for the Motion 12), so 60 to 80Hz would be a good starting point and tweak from there.

 

[alcoholbob]

If you use 2 pre-outs then you will boost output, theoretically up to 3db although in practice probably less.

 

[Howard]

If you use 2 pre-outs then you will boost output, theoretically up to 3db although in practice probably less.

The limit will still be either the amp's power output or the sub's excursion. Doubling the amplitude of the line-level signal (even if that is really what happens) is just kinda like cranking up the volume, so it's pointless.

 

[Howard]

The crossover should be set at 1.5-2x the F3 of your speakers (40Hz for the Motion 12), so 60 to 80Hz would be a good starting point and tweak from there.

That's a very interesting rule of thumb.