I need advice on a subwoofer or two!!!

[Khromo]

Thanks in advance for any help you can offer!

This is a moviecentric 5.1 system. Three 3-way Emotiva LCR's and two 2-way Emotiva SS's, all long discontinued but pretty good speakers. All five speakers are crossed over at 80 Hz, which is their F3. I have a 15.5' x 21.5' or 5 x 6.9 meter room, with the display mounted on a short wall. I like my tv and especially my movies and music LOUD! Theater, concert loud. Not all the time, but that kind of performance has to be available sometimes. To drown out the voices!

I have been using a home built subwoofer using a 15" Dayton Audio (that's Parts Express' house brand) Reference Series HF driver, a DA 500 watt plate amplifier, and a 3 cubic foot/85 liter sealed box. It gets down to an honest F3 of 37 Hz, and it literally shakes the floor of the second story room we use as The Home Theater And Musical Instrument Room. The current sub is very satisfactory, but it is 15 years old and it has some tough mileage on it. My plan is to build a replacement or two, and rotate this 15x500 sub to The Woman's Den.

My question is whether a left and right sub are appropriate for a room this size or is the single sub off to one side close enough for 80 Hz and lower.

I'm getting all the bass I need with one sub, would I really appreciate better seperation having left and right subs in a room this size? Not a lot of room here. The current sub wailed if I placed it any closer to the back wall.

 

[Madrok]

“My question is whether a left and right sub are appropriate for a room this size…”

Probably not, but face it, you’re a speaker building addict and your hands and wallet and itching! Absolutely try two subs, so you’ll get to experiment with the setup. Replacing your 15” with another, different single sub is asking to be disappointed.

The hardest thing with subs, IME, is getting them to cross over to the mains well, so you get enough midbass. Two subs should make that…different. I’d put them just inside the two stand-mounted speakers. Change it up from corner loading, and try a higher xover freq.

 

[Tom Gilman]

Apologizing in advance, but based on the picture provided I'm certain that some well placed absorbers and diffusors will make a bigger improvement in your room than any subwoofer upgrade.

 

[Jeff Scott]

To drown out the voices!

 

[johntoste]

Two subs can provide smoother low-frequency response, even in a moderately sized room.

As far as stereo separation at 80hz and below, many people maintain that bass is omnidirectional at those frequencies. Also, summing low bass to mono is common practice in mixing and mastering stages.

Nevertheless, I prefer to run my pair of subs in stereo.

I would also seriously consider using room treatments, including bass traps.

 

[120db]

I replaced my REL single sub with a matched pair of servo subs running in stereo through a minidsp crossover that incorporates Dirac Live to eq and correct for the room acoustics, it made a nice improvement, however, this is in a dedicated two channel system. In my home theater system I just run a single sub and am ok with that.

 

[Khromo]

If there were a strong consensus on adding a second sub to get better separation, I would look that way. I think this room is too small to get involved beyond one good sub.

I can improve on the existing sub, so I will build an enhanced replacement and rotate the existing sub to The Woman's Den, where the audience has different requirements!

The points on room treatment are well taken. I have put that off too long. I have some Owens Corning 701 and 703 standing by, so I just need to dive into where and how to do it!

 

[johntoste]

"The points on room treatment are well taken. I have put that off too long. I have some Owens Corning 701 and 703 standing by, so I just need to dive into where and how to do it!"

Check this out as an intro:


This is one diy approach:


These videos are bass-centric. I've chosen them because bass is foundational, and it's what we've been talking about.

Looking at your pic, I see large, flat, hard surfaces. These usually cause reverberant reflections which also need to be tamed.
Clap your hands. If you hear prominent echo, you need treatments. These could be as simple as rugs, tapestries, or overstuffed furniture. Or, you may need to make/buy absorbing panels. Particularly at "first reflection points."

Good luck, and for the love of the audio gods, don't use foam!

 

[Khromo]

Getting started, I'm thinking I can get three corners, and the ceiling and one wall 1/3 of the way back with GIK panels for about $1,400 (about $270 of that is shipping and tax). There is a big window on the other wall, so I think I will have to compromise with some heavy theater curtains there. The odd corner has shelves stocked with various excellent liquor, so it will not be molested. Those of us from the noble State Of Rhode Island have certain priorities.

I'm thinking that should provide a pretty good improvement. I think I will save myself the time involved in DIY on this one, as the GIK panels should perform and look good. I can probably hang them in no more than a couple of hours, while doing a decent job of building ten panels (four triangular) would take much longer.

I can measure the results before and after I get that much installed, and if I feel I need more help I can add a few more panels to the ceiling and the back wall. The room has shelves of DVD's and CD's, and a couple of windows to cope with, but I think taming the corners and 2/3's of the early reflection points should make for a reasonable compromise!

It's unfortunate that I'm still accumulating Blu-Ray's and DVD's, because this is a good size and shape to be starting with.

I appreciate all the comments. The subwoofer project is now officially on the back burner until I have completed responsible acoustic treatment!

Then a proper riser.

 

[Jeff Scott]

The odd corner has shelves stocked with various excellent liquor, so it will not be molested. Those of us from the noble State Of Rhode Island have certain priorities.

I would think that if you consumed enough of your excellent liquor your audio problems would not be a problem any longer...

 

[Khromo]

I would think that if you consumed enough of your excellent liquor your audio problems would not be a problem any longer...

Jeff, I think it depends on what we mean by "enough". There's a lot of room for interpretation in there!

Actually, this thread and the link to audio advice have got me rethinking a few other issues, including placement of the L and R speakers, and the height of the proposed DIY riser. I am a little excited!

 

[Jeff Scott]

Jeff, I think it depends on what we mean by "enough". There's a lot of room for interpretation in there!

Actually, this thread and the link to audio advice have got me rethinking a few other issues, including placement of the L and R speakers, and the height of the proposed DIY riser. I am a little excited!

You'll know when it's enough.

 

[Khromo]

GIK Acoustics Room Kit Package #4 - GIK Acoustics

GIK Acoustics offers 4 economical and ideal room kits with bass traps and acoustic panels to address room acoustic issues that fit within your budget.

www.gikacoustics.com

After considering the DIY options, I decided this package from GIK was well suited to my room, and reasonably priced (A hair under $1,500 after shipping and tax.). The DIY option would certainly save some money, but I'm at a point in my life where I have a little more money than time!

I can treat three corners (the fourth is inaccessible because someone stores a pile of valuable alcoholic liquor there), hang two clouds, and cover one of the hot spots on one wall. I'm missing three of the hot spots on the walls and one corner, but that can't be helped at this time.

I'll measure the room as best I can before and after. This has to be an improvement, because this room fails the clap test with flying colors! I will consider adding some more panels later if I think it needs it, but there isn't much available space left.

Am I wasting money? Is there a better alternative?

 

[Silent Sound]

You can't distinguish direction in low frequencies, so you gain nothing other than maximum volume with a second sub. For instance, a 120 Hz frequency has a wavelength of around 2.9 meters. That's much, much larger than the space between your two ears. So your two ears are picking up the same wave, so they're not able to distinguish direction. And 120 Hz is probably around or above the crossover frequency of your sub.

If you're having trouble with stereo separation, look to getting some sound treatment on the first reflection points from the speakers to the primary listening position. You're probably hearing the reflections from the other speaker and it's smearing the sound stage.

 

[Steve Dallas]

You can't distinguish direction in low frequencies, so you gain nothing other than maximum volume with a second sub. For instance, a 120 Hz frequency has a wavelength of around 2.9 meters. That's much, much larger than the space between your two ears. So your two ears are picking up the same wave, so they're not able to distinguish direction. And 120 Hz is probably around or above the crossover frequency of your sub.

If you're having trouble with stereo separation, look to getting some sound treatment on the first reflection points from the speakers to the primary listening position. You're probably hearing the reflections from the other speaker and it's smearing the sound stage.

Absolute rubbish.

Start here:

Subwoofer / Low Frequency Optimization

Subwoofer / Low Frequency Optimization By Amir Majidimehr [Note: This article was published in the May/June 2012 issue of Widescreen Review Magazine] Do you remember the scene in the movie Stargate where Daniel Jackson decodes the symbols that allow them to open the Stargate to travel to...

www.audiosciencereview.com

There are many, many other scientific sources which prove you assertions incorrect.

 

[MagusFaerox]

Absolute rubbish.

Start here:

Subwoofer / Low Frequency Optimization

Subwoofer / Low Frequency Optimization By Amir Majidimehr [Note: This article was published in the May/June 2012 issue of Widescreen Review Magazine] Do you remember the scene in the movie Stargate where Daniel Jackson decodes the symbols that allow them to open the Stargate to travel to...

www.audiosciencereview.com

There are many, many other scientific sources which prove you assertions incorrect.

He's right about one thing: You cannot localize bass in small rooms.

He's wrong that it's about volume. It's actually the opposite: because you can't localize bass, you can place subwoofers in a room so that they excite room modes differently and configure them for an absolutely amazing low end response without damaging the stereo image.

As far as I'm concerned, the absolute minimum number of subwoofers in any room is 2.

As the room gets smaller, it's more important, and you start to see more of a benefit from 4. But, the big difference is that the sweet spot is smaller with 2.

Bass management, including time-offsets, for 4 subs is hard to do outside of software. It's somehow still a niche thing for some strange reason that I will never understand.

 

[Rex Anderson]

Google Todd Welti and read his papers on the use of multiple subwoofers. If you don't want to build them, I recommend Rythmik subs.

Rythmik Audio • Direct Servo subwoofer products

New video interview of Todd Welti: discusses subwoofers...

This video is by the AV Rant guys. Really well done.

www.avsforum.com

 

[Khromo]

Google Todd Welti and read his papers on the use of multiple subwoofers. If you don't want to build them, I recommend Rythmik subs.

Rythmik Audio • Direct Servo subwoofer products

New video interview of Todd Welti: discusses subwoofers...

This video is by the AV Rant guys. Really well done.

www.avsforum.com

Thanks for that link, Rex. That is some great reading!

 

[Rex Anderson]

GIK Acoustics Room Kit Package #4 - GIK Acoustics

GIK Acoustics offers 4 economical and ideal room kits with bass traps and acoustic panels to address room acoustic issues that fit within your budget.

www.gikacoustics.com

After considering the DIY options, I decided this package from GIK was well suited to my room, and reasonably priced (A hair under $1,500 after shipping and tax.). The DIY option would certainly save some money, but I'm at a point in my life where I have a little more money than time!

I can treat three corners (the fourth is inaccessible because someone stores a pile of valuable alcoholic liquor there), hang two clouds, and cover one of the hot spots on one wall. I'm missing three of the hot spots on the walls and one corner, but that can't be helped at this time.

I'll measure the room as best I can before and after. This has to be an improvement, because this room fails the clap test with flying colors! I will consider adding some more panels later if I think it needs it, but there isn't much available space left.

Am I wasting money? Is there a better alternative?

I work with guys who do room treatment design and remote room tuning. PM me if you are interested. We use Vicoustic products. https://vicoustic.com/

 

[dcbc]

I've got a Dayton 12 in our home theater. That thing has been as rock solid as any sub I've had for movies. Something tighter for music might be a different answer.