Two Subs Better Than One?

[gene]

The answer to this question is typically yes, assuming you’re comparing one vs. two subs of the exact same brand and model #. In almost all circumstances, installing multiple subwoofers in your theater room will yield significantly better and smoother bass response across a wider listening area due to modal averaging. When deciding on getting either a single large sub, or two smaller ones, I'd usually recommend the latter. If its a hard sell to your wife, tell her you're not doing it for yourself but for the benefit of your mother-in-law.

Read: Are Two Subs Better than One?

 

[nickboros]

Gene,

You weren't really specific about the subwoofer placement and setup. Usually with two subs it is recommended that they are located at the midpoints of two opposing walls in a rectangular room, but it didn't sound like you did this and yet still got very nice results. Also, what about phase? Usually they are supposed to be out of phase with each other. I think that the Axioms just have a 0/180 degree toggle switch. So, were they out of phase with each other?

- Nick

 

[gene]

Gene,

You weren't really specific about the subwoofer placement and setup. Usually with two subs it is recommended that they are located at the midpoints of two opposing walls in a rectangular room, but it didn't sound like you did this and yet still got very nice results. Also, what about phase? Usually they are supposed to be out of phase with each other. I think that the Axioms just have a 0/180 degree toggle switch. So, were they out of phase with each other?

Sorry Nick but I lost my license for Visio and couldn't do a room sketch.

Basically sub 1 was placed towards the front left corner behind the "mother-in-law" couch.

Sub 2 was placed almost diagonally across from it towards the back right of the room which opens into the kitchen.

There was no need to configure them out of phase as they blended much better in phase. I adjusted subwoofer distance until it blended best with my mains. I will try to edit my article to clarify this.

 

[GlocksRock]

Get google's sketch up and make a drawing... it's free and pretty nice too actually.

 

[lsiberian]

This again demonstrates why it's better to have 2 decent subs rather than one great sub. You sacrifice some output, but you can't match the quality and correction you get.

 

[no. 5]

You weren't really specific about the subwoofer placement and setup. Usually with two subs it is recommended that they are located at the midpoints of two opposing walls in a rectangular room, but it didn't sound like you did this and yet still got very nice results.

That is but one recommendation for placing two subwoofers, and in any event, it is only a starting point, as listener position and acoustics of the room really have the last say about what locations are best.

Also, what about phase? Usually they are supposed to be out of phase with each other.

There too, the measured behavior of the subs in room will dictate what needs to be done to make them play well together, not the simulated ideal, as even rooms with the same dimensions can have different low frequency behavior depending on construction, doors, windows, etc.

 

[gene]

Guys;

I placed a link to Multi Subwoofer Connection Guide in my article that gives you possible layout scenarios for optimal sub placement. I also discuss how to connect them and set them up properly.

The problem with generic placement suggestions is they typically only work in rectangular rooms that have 4 walls. Most people don't have this luxury. Even if they do, they almost can never place them on the mid points of each wall due to asthetics. This is why I recommend placement symmetry as much as possible to create that "virtual" subwoofer effect that I described in my article. If you don't have test gear, use our "Crawling for bass" techninque to find the optimal placements. Good luck.

 

[Matt34]

Great article, I could get away with running a single sub in my old, small, sealed dedicated room but in my large open floor plan living room you have to run multiple subs to get a decent FR.


Edit: Cause I can't type on my BB.

 

[nickboros]

Thanks gene and no.5. You cleared up my questions.

 

[Davemcc]

I know everybody says that you should only use identical subs, but I had awesome results running my PB12-Plus and STF-3 in tandem. Even when the situation isn't ideal, experimentation can be your friend.

 

[Matt34]

I'm waiting on one more amp to get here for my dual sealed/dual ported setup. I'll have the sealed subs flanking the seated position and the ported subs up front on both sides of the TV. I'm going to need more EQ capabilities with this arrangement but I hope it will give me the crazy spl and sound quailty I'm after.

 

[ThA tRiXtA]

Nice article Gene.

I appreciate these types of articles. When I bought my last sub I actually bought two specifically based on the recommendations made in the Audioholics multiple sub article.

I just have two questions, one of which was sort of asked already.

In this current article, you stated:

"If for some reason you can’t, then it’s usually best to average the distance between the two subs for the electrical delay in your processor and tweak from their using variable phase or EQ to better hone in your response."

Both my subs are not equidistant from my listening position... so if I measure the distance from each sub to the listening position and divide that number by two and use that result for the delay value in the AVR, how much of a compromise comes in to play with using a compromised value like that?

What are your recommendations on determining the proper phasing of each separate sub? Is it as simple as phasing each sub separately by measuring output in terms of SPL to determine the correct setting, or is it more complex than that?

Thanks for your time.

Edit: on a general side note, when you take distance measurements from speakers to listening position to enter the distance in the AVR do you take the measurement from the face of the speaker or sub, from the middle of the enclosure/cabinet or? I have never heard anyone comment on this before and I am curious.

I ask because my LCR cabinets are all of the same depth, but my front sub is obviously much deeper... so should I move the LCR channels forward into the room to match the distance measurement of the sub, or should I move the sub closer to the wall? Obviously both scenarios will alter the response of those channels. Does it even matter to align your front speakers distance wise?

 

[gene]

All;

Using Google Sketch, here is a concept drawing of the Family room and where I located the subwoofers. I also updated the article with this image. Thanks for the suggestion.

 

[ninja12]

Dual Subs

I can truly say that I am a believer of mulitple subs. I just added a second sub to my set up, and all I can say is WHY DID I WAIT SO LONG. It has truly taken my system to a whole new level. Now, you really hear and feel the bass in every seat. Before, the bass was good in the "sweet spot" and the seat closer to the sub. The other seats, further away from the sub, sufferred. Now, no seat suffers. It's all good now.

 

[lsiberian]

Edit: on a general side note, when you take distance measurements from speakers to listening position to enter the distance in the AVR do you take the measurement from the face of the speaker or sub, from the middle of the enclosure/cabinet or? I have never heard anyone comment on this before and I am curious.

I measure from the tweeter to the ear level of the center seating position.

 

[GlocksRock]

I'm glad to see you using sketchup. They use that for all the drawings on Man Caves, on the DIY network... it's a sweet program.

I would love to run dual subs, but I don't have the space for them in my current room, but one day I will make it happen.

 

[annunaki]

I know everybody says that you should only use identical subs, but I had awesome results running my PB12-Plus and STF-3 in tandem. Even when the situation isn't ideal, experimentation can be your friend.

Those subs are also of very similar performance level and output.

 

[gene]

using identical subs is usually easier to integrate. That being said, I run 2 velodyne DD15s and 2 RBH T30 subs in my main theater room which are drastically different subs. The reason why I got it to work very well is b/c the Velos allow me to change the slope of their low frequency roll off below 20Hz which I got to mimimick my ported T30s. The result is sonic heaven but it took some time and test gear to achieve.

 

[GlocksRock]

I wanna take a field trip to Gene's house to check out his theater rooms.

 

[JLMEMT]

I wanna take a field trip to Gene's house to check out his theater rooms.

Load up the bus. We will all be at Gene's for dinner!