Dual Subwoofer

[harkpabst]

I cannot believe that. In a corner bass increase due to wall placement is biggest. So modes are going to be bigger too. Same counts for loudspeaker in general - never put them in a corner. Well, then you have additional issues with practically no soundstage etc…

Honestly I was not expecting this question from you…

It's a fact, it works. Room modes don't get bigger because the amplitude is bigger. Think about it, room modes depend on room characteristics and how the room is excited.

Corners are perfect for placing subs (but not for the main speakers) if you can compensate the extra gain. In fact, since room gain increases the efficiency it effectively virtually boosts your subwoofers available power.

One advantage of using subwoofers is that you can place the mains and subs independently. Place the mains optimised for least early reflections, place the subs for optimal pressurising the room.

And it's not just great in theory, it actually works in practice (e.g. in my living room). It's not a matter of belief or disbelief.

 

[slartibartfast]

It's a fact, it works. Room modes don't get bigger because the amplitude is bigger. Think about it, room modes depend on room characteristics and how the room is excited.

Corners are perfect for placing subs (but not for the main speakers) if you can compensate the extra gain. In fact, since room gain increases the efficiency it effectively virtually boosts your subwoofers available power.

One advantage of using subwoofers is that you can place the mains and subs independently. Place the mains optimised for least early reflections, place the subs for optimal pressurising the room.

And it's not just great in theory, it actually works in practice (e.g. in my living room). It's not a matter of belief or disbelief.

When I tried placing my sub in a corner I didn't get the expected increase in output. I don't know if putting it between a leather sofa and the corner makes any difference.

 

[harkpabst]

When I tried placing my sub in a corner I didn't get the expected increase in output. I don't know if putting it between a leather sofa and the corner makes any difference.

It probably does.

My stereo subs (connected to the Lyngdorf) are each in one corner of the room and the gain is measurable.

 

[Smartplug]

It's a fact, it works. Room modes don't get bigger because the amplitude is bigger. Think about it, room modes depend on room characteristics and how the room is excited.

Corners are perfect for placing subs (but not for the main speakers) if you can compensate the extra gain. In fact, since room gain increases the efficiency it effectively virtually boosts your subwoofers available power.

One advantage of using subwoofers is that you can place the mains and subs independently. Place the mains optimised for least early reflections, place the subs for optimal pressurising the room.

And it's not just great in theory, it actually works in practice (e.g. in my living room). It's not a matter of belief or disbelief.

Are you using 2 subs? I don’t know what to expect on dual sub till I connect the other though not same brand but it pressurized the room nicely. With the second one connected I got much deeper soundstage than it was using single sub. I also noticed balanced soundstage that doesn’t collapse when you’re moving around the room. I don’t mind getting matching model if that makes difference or leave it as it is.

 

[MCG555]

I don‘t need to boost bass, I want the bass from the music not the one from the room. If I listen to silent music I do not have an issue with room modes. If I listen louder I do have one. So tell me why room modes are not become bigger when amplitude is getting bigger?

I did not try it with RC, BUT I tried it before and corner placement was not good!
Best in my room would be in the middle of the room, next to where I am listening to usually. This is not possible because I do not have an AC sockets there and I don’t want to have cables lying around. I have now one SUB at one wall of the room and the other SUB at the other wall of the room. Also not perfect, because they are too close to the wall? But this was - in my case - the best solution. …

 

[Wiimer]

Are you using 2 subs? I don’t know what to expect on dual sub till I connect the other though not same brand but it pressurized the room nicely. With the second one connected I got much deeper soundstage than it was using single sub. I also noticed balanced soundstage that doesn’t collapse when you’re moving around the room. I don’t mind getting matching model if that makes difference or leave it as it is.

I refer to this.

Are multiple subwoofers better than one?

Is it better to have multiple subwoofers instead of just one? In this article, our R&D Engineer Prathmesh Thakkar, talks us through room modes and how adding a second subwoofer can elevate your sound performance even further.

hk.kef.com

Once you have positioned your first subwoofer and identified your problem room mode, play a pure tone at the frequency and crawl around the room again. This time, you are trying to find the position in the opposite half of the room where that note sounds the loudest. This will be in the high-pressure region. Simply place your second sub at that position and go back to your listening seat. Don’t forget to update the pre-set by telling the KEF Connect app that you now have two subs. You should notice that the note is a lot quieter than before (with just one sub). This proves that the mechanism is working.

 

[jeffme]

So tell me why room modes are not become bigger when amplitude is getting bigger?

If the >1 subwoofers were offset by a wavelength, then I believe this might be the case. But, in most practical situations, the offsetting locations, and wall modes offset each other. The peaks are offset by valleys and vice versa. In addition, because you have 2 sources of bass, you can play each at a lower volume and get similar richness.

Using >1 subwoofer and placement of subwoofers really is a pretty settled discussion - more than 1 is better, and placement in corners is generally a good thing, although, as you point out, every situation can be different, but most situations are not. Testing and doing a subwoofer crawl is a good practice, and - as you have discovered, so is putting them against opposite walls is also good practice.

Here are some reference links to help provide background:
- SVS (subwoofer vendor) articles:
-- The Art of Subwoofer Placement
-- Why go dual subwoofers?
- Harman International - JBL/Infinity/Revel tech deep dive powerpoint
- Audio Advice (website):
-- How to set up dual Sonos subwoofers (applies to all subwoofers, not just Sonos)
-- Home Theater subwoofer placement (applies to audio as well)
- How to place subwoofers using REW (Room EQ Wizard) video

From the JBL tech deep dive:


From the second Audio Advice article:

 

[MCG555]

Thank you!