2 subwoofers or equalizer?

[LA-384]

Hello all,

I am a brand new member on Audioholics. I've been watching Gene and Hugo's video's for a few months now, and stumbled upon the video about multisubs and minidsp. It got me wondering if i should go the same route.

About a year ago i bought a BK XXLS400. Although i'm pretty pleased with its performance (decent bass and no angry neighbours), i keep wondering if i made the right choice. Back then i contacted the guys from BK and they actually advised me to get a monolith or monolith+ (due to roomsize). Not sure why i went against their advise, probably because the huge sizedifference of the sub and my fear that the neighbours would get more bass-output than i did .

When setting up, i did do a subwoofer-crawl, but couldn't really hear any difference, so i put the sub closest to the primary listeningspot, which was also furthest away of the wall seperating my home to that of my neighbours. I do think that the short distance to the subwoofer, makes it perform better than it should when it was placed at the "ideal position" (next to the front speakers).

After watching the video about minidsp and the fact that i can get a second hand BK Monolith for a reasonable price, it got me wondering if i could increase the performance of my setup and what would be the best way to do it.

Should i buy the Monolith, and a minidsp and go for a multi-sub solution.
Or should i buy an equalizer (like an anti-mode 8033) and try to get the max performance out of the xxls400?

I know that i should first measure it's current performance, so i bought a minidsp Umik-1, which will arrive in a week or so. But is it possible to give some expectations without measurements?

And my most important question (which i'm still not sure about). Is it expected that the neighbours will experience higher output also, when i'm optimizing my bass? Although they are an older couple, and probably have limited hearing-capabilities they won't be living there forever.

Oh, this is the (far from ideal) room-layout. It's a livingroom, so the placement possibilities are very limited.

Option A (sub could also be placed in between the lamp and the closet):

Option B:

 

[tyhjaarpa]

Welcome!

I personally went for second XXLS400 recently and I'm really happy with the result. Main reason for me wass to even out the bass response.

Are you looking for more output or more even bass response?

I'm pretty sure that people can share their experiences with mini dsp and equalizers.

Here are my experiences with the XXLS400's:
http://forums.audioholics.com/forums/threads/best-subwoofer-for-money-under-2000€.95750/

 

[LA-384]

Thanks for your reply! I'll be reading up on your experiences shortly.

The thing is, i don't really know what i'm missing. I've set it up using audyssey multeq xt from my Denon 2113. Crossovers are set to 90 for the fronts and 100hz for the center and surrounds. After setting up i tweaked subwoofer output a bit by adding a bit of gain on the sub itself.

It's just that the performance seems almost random. Sometimes i get pretty heavy bass (not that i can feel it, but i hear stuff rattling around a bit). Other times it's as if there is hardly any bass. Prior to the audyssey run, i put the gain knob at 9 o clock. This resulted in a receiver levelcorrection of -2db. I later added a bit of gain, the knob is now in between 9 and 10 o clock. So there is a lot more room, but i doubt it will give a more consistent bass, just louder.

I'm also not sure what i should expect out of a good performing subwoofer. People say you should only notice it when it's turned off, but then i guess that is only true for music. With movies you'd want to get a bit more kick i think.

Keeping in mind that the folks at BK actually advised the Monolith, i can't help but think that the bass-response is not living up to it's potential. To be sure i'll just have to wait until i can do some room measurements ofcourse.

 

[TheWarrior]

If you're a solo listener, one is plenty. But if you want other seats to share the experience, multiple subs are necessary.

Music and movies are mastered very differently, as well as being inconsistent. I use an Oppo 93 for both, and just change preamp inputs, one for CD, one for BD, so I can have adequate bass for each.

Minidsp requires some working knowledge of small room acoustics and how to program each subwoofer. I use minidsp plate amps for subs I build. But you must understand the phase relationship multiple subs apply to a room vs. listening position(s). You can have 4 subs, but still put your seat in a null.

 

[herbu]

In an apartment you're going to be limited by neighbors no matter how many subs you have. While you can certainly build, (and pay for), a system capable of chest thumping and bladder shaking bass, it sounds like you won't be willing to use it. So I'm not sure I'd spend money that way now.

Regarding varying bass, again there's nothing you can really do about it. It's the sources, not you. And it's different shows/discs from the same source. Like TheWarrior said, you can have different AVR settings set up for different inputs. So at least you can, for example, setup a neutral/accurate bass level for music CDs, and enhanced bass for Bluray movies and TV. That's about as good as it gets.

 

[tyhjaarpa]

Like pointed out already the bass you have really depends on the source material. Your sub should be quite capable.

 

[LA-384]

Thanks everyone for your replies. Now i think i overestimated the effects of multisub/equalisation for a single listening position. Although i don't live in an apartment, the home is adjacent to another one. I believe you call it a "semidetached" home. Not sure if that changes your opinion on the matter.

I guess i'll just have to wait until i can do some measurements with the Umik-1 mic. To see how the response is right now. I'll post back afterwards, to check if/what can be improved and how.

 

[herbu]

Now i think i overestimated the effects of multisub/equalisation for a single listening position.

When you put a single sub anywhere in your room, it will result in peaks and nulls. Think about dropping a rock into a small pond. The ripples will reflect off the sides of the pond, and any stumps/sticks/rocks/obstructions in the pond. In some places these reflections will be additive. In some places the reflections will tend to cancel out other ripples.

For any single position you choose in the pond, there will be places you can drop the rock such that your chosen position receives minimal additive or cancelling reflections. Rather it gets an "accurate" ripple from the rock.

Placing a single sub in your room is like that. There will be places you can put the sub so your single listening position gets accurate bass sound waves. Other seats in the room may sound hot or soft, but your seat sounds "right".

Multiple subs are to mitigate the "distortion" for other seats, not yours. You can adjust the sub volume a couple different ways so its level is accurate in your seat... pretty much regardless of where you place the sub. Maybe the peaks are even higher, or the nulls are even lower in the "other" seats... but does that matter to you? Maybe not.

In short, it's easy to set the volume from a single sub "correctly" for any one seat.

 

[LA-384]

Hm, thanks for clarifying that. I believe you are talking about standing waves? Aren't those mainly caused by the room itself, instead of the location of the sub? Or at least the most prominent ones (formed by axial modes). Not sure how noticable the others would be compared to the axial modes.

Yesterday was a good example of what i meant by a variable subwoofer output. I was watching a movie and had to put up the gain a bit to get a decent rumble when it was needed. About half way it appeared that the sub was outputting a lot more all of a sudden, so i had to lower the gain again. Ofcourse it could be that the latter rumble was at a frequency that caused a peak at my listening position, since if i'm correct, each frequency also has different locations of peaks and nulls.

If that's the case, it would be very difficult if not impossible to get a flat frequency response with just one sub. Wouldn't a second sub or maybe better equalization (minidsp or anti-mode) get rid of these peaks and nulls?

 

[shadyJ]

If that's the case, it would be very difficult if not impossible to get a flat frequency response with just one sub. Wouldn't a second sub or maybe better equalization (minidsp or anti-mode) get rid of these peaks and nulls?

This is mostly correct. You need multiple subs with proper placement to get rid of the nulls, and equalization to get rid of the peaks. Remember you can not just place the subs anywhere, they have to go where they shore up the nulls.

 

[herbu]

...each frequency also has different locations of peaks and nulls. If that's the case, it would be very difficult if not impossible to get a flat frequency response with just one sub.

Well, there is a slope of diminishing returns. Everyone has to decide how far they'll go. I'll wager for 99.999% of the people with a single listening position, the sub crawl, crossover and volume adjustments can make a single adequate sub satisfactory.