2 subwoofers

[FunkyMonkey]

I have been meaning to re-run Audyssey for a while now that I have the app.
Before I do so, please can you advise me?

I have an old Velodyne VX10 subwoofer and a newer Canton 10.2 subwoofer.

They are both forward firing.

Currently, I have the Velodyne under the centre speaker (the centre is on a stand that doesn't touch the sub, and the Canton is behind my sofa so as to fill the base of my surround wall-mounted speakers which are Tannoy Revolution DC4 (small speakers that only go down to 100Hz if lucky).

So before calibrating, where should the subs go given my speaker set up which is:
Floor standing fronts
Big bookshelf sides
Big centre
small rears
4 ceiling mounted cubes

It's a 7.2.4 Atmos setup.

 

[davidf]

A good subwoofer will always reach deeper than virtually any size pair of speakers - it’s what it is (supposedly) designed to do.

Whether or not two different subwoofers should be used in one system depends on whether the receiver’s EQ system can measure and EQ two subwoofers independently - if it can’t, it’ll treat the subwoofer’s output as a single sum, and EQ based on the result, which gets the best out of neither sub. You could run one of the subs from the speakers outs from the receiver in-line with the rear speaker outputs and have the receiver measure and EQ the small rear speakers as full range using the sub.

 

[FunkyMonkey]

Yes my receiver does EQ both subs independently first and then together.

Like the idea of dedicating the rear sub to the rear speakers but it seems an overkill for the 2 rear speakers when I have 9 other speakers

 

[newlash09]

If you have equidistant walls to either side of your listening position. But I prefer keeping the sub near the rears. I have floor standers for fronts. And iam not worried about even bass response all over the room. All of us at home sit on a big sofa to watch TV or movies. So a sub on each side, equidistant from the centre of the sofa will be ideal for me. I presently have only one sub to the right of the sofa. But will be adding one to the left. Bass has to be felt at seating / listening position. The rest of the room can take a walk. I might be wrong, but do give it a try. You might end up liking it like me

 

[FunkyMonkey]

Thanks. That could work. Issue I have is I can hear direction of bass even at 80hz. And given my subs are different wondering if left and right would work.
Also probably a stupid question but would I need to point the subs at the main listening position?

 

[ellisdj]

It wont work like how you think.

If you crossover the speakers at say 100hz at the rear it will sum mono the below 100hz in with the LFE channel which is 120hz and below.

Technically having a sub at the rear is not to have the bass with your rear channels it doesnt work like that.

What it does give you is a different point of bass into the room which can alleviate room problems or create some, probably alleviate some nulls.

Also having a sub closer to the listening position can have a positive impact on the tactile bass you feel so there is a benefit there.

Having a sub at the back so you have bass with the rear channels unless its crossing over up in the 200-300hz range then its not actually doing what you think - its just your perception of it thats tricking you - nothing wrong with that.

The negative effect of having subs away from boundaries is you lose some impact from the subwoofers especially in the low end - most small subs are totally room gain dependent for any deep bass and for example corner loading them extends their freq response massively.

This is why people have 4 subs one in each corner to get all the benefits of the above with none of the weaknesses

I hope that might help you make a decision

 

[FunkyMonkey]

Thanks for the lengthy post.
My subs are both against walls. My rear speakers are 4 inch Tannoys and so the bass crossover is approximately 120hz although I cannot remember exactly. May be higher.

 

[ellisdj]

You can have subs at the front of the room and still get bass effect at the back of the room.

The speaker creates the placment cue and the subs fill in the rest. at 120hz there probably is some audible bass at the rear but I would bet its still hard to detect.

I crossover at 120hz all around and wouldnt let that affect my decision on sub placement - more important to get the right amount, impact and extension from the subs than worry about the little bit that might or might be missing from the rears.

In Movies bass is 75% of the experiennce imo its the make or break of the movie actually being an experience and not just a film you watch

 

[FunkyMonkey]

Ellisdj, I cannot put both at the front as they woudl be unsightly. I could try putting them at the sides and see hwo that goes. Thanks. Althogh the sides of the sofa are close to the side walls (it is a very wide sofa), so as these are forward firing subs, this may present its own issue

 

[newlash09]

Of 80hz makes the bass directional at the frequencies closer to 80hz. That was the reason I had suggested having 2 subs, one on each side equidistant from your seating position. This would cancel out the directionality that you can hear now.

And the idea of having the sub's next to the sofa was not to complement the rear channels. In my listening room of 11x17 ft, with the floor standers firing down the shorter wall, I felt the subwoofer sounded best closer to the sofa. When placed in the front of the room, there was too much reflection off my back wall.

However if your room shape or size is different, your mileage might vary. And I also found that setting all your speakers to crossover at the lowest frequency your small surrounds can go down to, also improved the bass cohesion in my room.

And don't worry about the two different subs, in most circumstances you might not be able to discern the difference. Do give a try and see if it works in your room

 

[ellisdj]

Ellisdj, I cannot put both at the front as they woudl be unsightly. I could try putting them at the sides and see hwo that goes. Thanks. Althogh the sides of the sofa are close to the side walls (it is a very wide sofa), so as these are forward firing subs, this may present its own issue

Subwoofer placement is not guess work, you need to put them in the right places in the room.

Its often suggested mid way along walls opposing so mid way along the front and rear wall which is where you seem to have them now.

Thats fine if the subwoofers have excellent natural freq extension and output - most small subs dont have this, far from it. Corner loading has its benefit for extension output and impact but doesnt mean its the only way