a sub in each corner

[Big Daddy]

Originally Posted by Blu-Dog

BD (ironic we share the same screen name initials), I don't want to belabor this issue, but in the very thread you cite, you give a sterling example of exactly what I'm talking about. I don't understand why you strongly disagree with my comment.

A person had a question, concerning subwoofer placement in an irregularly shaped room. He gave significant detail about the features of the room, and his current subwoofer placement. He asked for advice; this was your response.


Clearly, you see it the same way I do. While there is science in the propagation of sound waves, the factors are so complex that it requires intuitive deduction, and active experimentation, to come up with the optimum solution. It is an art, the same way a painter understands the blending of colors that is defined by certain rules in the visible spectrum to obtain an effect, or the designer of an aircraft tries different configurations to acheive the optimum shape. In both cases, software simulations and rules of engineering and science are a starting point only.

Clearly, you have a deep understanding of these rules, yet they are only a starting point for experimentation - and the precise science behind these rules are often ignored by brute force to obtain a desired result. Clearly, you've followed this non-scientific, artful method yourself, and recommended it to others.

While I have not documented all my subwoofer builds for this forum (you do an excellent job of this), I currently have three custom built subs in my home, and have just delivered two more to one of my sons. I'm prepping two new additional bulds for my other son.

There is the scientific ideal, and then there is the wife, making sure we don't throw out all the seats to place a subwoofer in an "ideal" spot - which may not make that much difference. While your advice about nulls and other critical matters is quite scientific, your advice to "Also, stack them on top of each other and decide if you like it" has a scientific basis, but is definitely an artistic effort.

I just want to be sure that if we are in disagreement, the differences in our opinions is substantial. In this case, I don't think it is.

I also think that you dispense excellent advice. Good work, my friend.

My disagreement was mainly over the highlighted statement: “Placement is an art, not a science”.

That statement is not accurate. The locations where a subwoofer can be placed in a home theater room can be scientifically predicted. The reason why some locations in the room work for placement of a subwoofer and some locations do not work has everything to do with the science of wave interactions and standing waves. I don’t understand the Art of placement. These locations are not random and require some calculation.

Let me clarify things so that there are no misunderstandings about subwoofer placement and my posts in the past:

1. In my posts, I have never directly or indirectly implied that science places no role in subwoofer placement.
2. In a typical rectangular dedicated HT room where you have many choices for placing a subwoofer, it is fairly easy to predict the best locations and where the nulls are. I have done that manually in the link I provided above. Alternatively, you can use an Excel Worksheet to predict room modes. There are other calculators of room modes such as: Calculator 1, Calculator 2, or Calculator 3.
3. Many people use their living rooms as their nondedicated HT rooms. These people fall into three categories:
   1. They do not have any knowledge of standing waves and room modes.
   2. They have heard of standing waves and have some basic knowledge of it, but they do not fully comprehend it or they are not in the position to perform calculations.
   3. They have full understanding of standing waves and room modes, but there are other considerations that prevents them from using scientific knowledge to find optimum locations for a subwoofer.
4. When you use your living room as your HT room, there are very few options available for placing a subwoofer because of several reasons:
   1. There are other furniture and obstacles in the room.
   2. They need to hide the subwoofer because of aesthetic reasons.
   3. They are afraid of offending your spouse and having to sleep in a doghouse.
   4. There are children or pets in the house and the subwoofer needs to be out of the way.
5. If your choice are limited because of the factors mentioned above, you need to experiment and find out the best location out of the very few options. That location may not be the best and optimum location for a subwoofer, but you have to compromise. I have always encouraged this group of people to experiment. My intention has never been to ignore scientific principles of wave interaction and room modes.
6. Let’s not forget that HT is about fun and enjoyment and not a physics lab. For this reason, experiments at National Research Council (NRC) of Canada and at Harman International have found that when you have four subwoofers and a typical rectangular HT room, the best positions for the placing the four subwoofers is the four corners of the room or the middle of the four walls. In all cases, the subwoofers should be placed a foot or more away from the walls so that they do not become too boomy.
   
   
   
   
   
   
   
   

In conclusion, placement of subwoofers in a room is all about science. Art plays no role.

[Blu-Dog]

BD,

You state: "In conclusion, placement of subwoofers in a room is all about science. Art plays no role."

It's a semantic difference in our statements. I read your post with great interest, as it contains much valid and useful information. I'm under no illusion that the factors involved have no scientific basis. The opposite is true.

What I was pointing out was that for virtually every home setup, which must coexist with whatever conditions are there, scientific principles must take a back seat in most configurations. I spent over two decades of my working career as a practical engineer, with a decade of that at Hughes Research in Malibu, so I know about science to some extent.

What I have learned is that often, existing knowledge is only a basis, and guesswork - and experimentation - is how things get done. Once done, the results are cast against the scientific principles on which the experiment was based, in an attempt to validate and repeat those results.

This is how it works in home theater. "It looks better over there" may or may not result in better sound, and most home enthusiasts are in no position to use software, or other tools, to dictate placement of gear in a given environment. It is very much an artistic exercise, as any viewing of the myriad home theater galleries will show you. If the results are audibly successful, it can be determined why through science, but there is no way for science to predict, and dictate with a measuring tape, exactly where things will go.

Advice on basic principles is helpful, which you dispense regularly and to good effect. They are not axiomatic; they're advisory. Not adhering to them is not heresy, witchcraft, or apostasy; it is art. Perhaps bad art, but art nonetheless. Some folks have lesser HTIB systems and soundbars, others have gear like ours, or even better. What may be rules to you is actually guidelines to others.

Anyway, I like your work, agree with your conclusions almost always, and will put our differences down to semantics. We really do agree, whether it bothers you or not.

[Movie Man Don]

Both Blu Dog and Big Daddy share very good points. In my case, trying to maintain a "theatre" type environment in my screening room it was impossible to install subs anywhere except behind the screen. As I shared in a older post I found that facing the subs toward each other (about 10 feet apart) produced an extremely satisfactory results. I don't think there is a cookie-cutter answer to sub placement all the time but surely the graphics offered by Big Daddy make a lot of sense. I think in my application using two commercial 18" JBL's with high power amps has over compensated for not having four subs. When those suckers kick in you don't have any idea where it's coming from and certainly there is no lack of "effects".....trust me.

[Blu-Dog]

Originally Posted by Movie Man Don

Both Blu Dog and Big Daddy share very good points. In my case, trying to maintain a "theatre" type environment in my screening room it was impossible to install subs anywhere except behind the screen. As I shared in a older post I found that facing the subs toward each other (about 10 feet apart) produced an extremely satisfactory results. I don't think there is a cookie-cutter answer to sub placement all the time but surely the graphics offered by Big Daddy make a lot of sense. I think in my application using two commercial 18" JBL's with high power amps has over compensated for not having four subs. When those suckers kick in you don't have any idea where it's coming from and certainly there is no lack of "effects".....trust me.

I may pre-date Big Daddy in this group, but I feel vindicated when I see his advice matches quite a bit with what I've done here, over time. I have done some unorthodox things, but they worked, basically by brute force (massive amps and high performance speakers), something many folks don't have space or money for.

What he has to say should be taken to heart by anyone fortunate enough to design a practical living space around home theater constraints. His basic rules of sub and speaker placement work very well for people who don't have all that apocalyptic gear, and want to optimize the equipment they can reasonably get on a practical budget. I've heard awesome sound from a budget under $1,000, even in fairly large spaces, and what he has to say makes it even better.

That stunt you tried, facing the subs against each other, I would never have attempted. The fact that you get spine-twisting bass out of it is amazing, and I don't know whether it has something to do with sonic properties or just two 18" JBL's, powered by slightly sub-nuclear reactors, in some kind of Godzilla mode.

It works. I don't know why, and I leave it to wizards like Big Daddy to figure it out. More than likely, he'd just listen, nodding his head, and say, "play that again, I need to run more tests," which is the way most scientists get the Nobel, anyway.

[MovieFanatic2010]

I know this is WAY off topic but i need help ASAP.... I bought a Pro Amp to Power my Transducers and i need to plug the Subwoofer cable into the AMP but the AMP only has Instrument cable inputs..... Here is a picture



Is there an adapter i need or do i need to return this AMP....Any help would be awesome.....Sorry for the off topic question and thanks....

[Blu-Dog]

Originally Posted by MovieFanatic2010

I know this is WAY off topic but i need help ASAP.... I bought a Pro Amp to Power my Transducers and i need to plug the Subwoofer cable into the AMP but the AMP only has Instrument cable inputs..... Here is a picture



Is there an adapter i need or do i need to return this AMP....Any help would be awesome.....Sorry for the off topic question and thanks....

You need an RCA to XLR adapter. Go to the closest Guitar Center - they have an adapter that goes from RCA to the three prong input - runs a few dollars.



http://www.guitarcenter.com/American...20-i1129379.gc

http://www.guitarcenter.com/Live-Wir...94-i1166781.gc



Big Daddy also has a line on a box running about $50 or so that won't diminish the signal - you get a little bit of drop going from RCA to XLR. He's a big fan of Behringer amps, they use the XLR adapters, too. I use QSC, same problem. He'll probably chime in at some point, but in the meantime, this is a quick fix. I've been using them for about five years.

[MovieFanatic2010]

Originally Posted by Blu-Dog

You need an RCA to XLR adapter. Go to the closest Guitar Center - they have an adapter that goes from RCA to the three prong input - runs a few dollars.



http://www.guitarcenter.com/American...20-i1129379.gc

http://www.guitarcenter.com/Live-Wir...94-i1166781.gc



Big Daddy also has a line on a box running about $50 or so that won't diminish the signal - you get a little bit of drop going from RCA to XLR. He's a big fan of Behringer amps, they use the XLR adapters, too. I use QSC, same problem. He'll probably chime in at some point, but in the meantime, this is a quick fix. I've been using them for about five years.

Thanks for the help

[Big Daddy]

Blu-Dog, I am glad we agreed that I am right and you are wrong. Just kidding.

Originally Posted by MovieFanatic2010

I know this is WAY off topic but i need help ASAP.... I bought a Pro Amp to Power my Transducers and i need to plug the Subwoofer cable into the AMP but the AMP only has Instrument cable inputs..... Here is a picture



Is there an adapter i need or do i need to return this AMP....Any help would be awesome.....Sorry for the off topic question and thanks....

Although you can buy one of the simple XLR to RCA converters and it may work, you may experience a significant drop in the signal level. That is because there is difference in the reference voltage level for balanced XLR and unbalanced RCA. You may need to buy a converter box.

Go to the middle of The Official Behringer & Other Pro Amplifiers Thread. I have included a section on this topic.

I have several pro amplifiers that power my multiple subwoofers. I use two Samson S-Convert boxes to convert the RCA signals to XLR. Unfortunately, Samson no longer manufactures the S-Convert boxes. However, you can buy either the ART Cleanbox Pro or Rolls converter boxes. These boxes are not an absolute necessity, but they help.

http://www.amazon.com/ART-CLEANBOXPR.../dp/B003S7T49K
http://www.amazon.com/Rolls-MB15b-MB...xlr+converters

[Blu-Dog]

Originally Posted by Big Daddy

Blu-Dog, I am glad we agreed that I am right and you are wrong. Just kidding.

I'm always right. I can prove it. This week's lottery numbers are...uh...well...let me get back to you next week on that. I got the proof around here somewhere...

[qx56]

Ok I forgot what this thread was about. I am convinced that 4 ported 12 inch subs tuned to 18-19 will make me happy. I plugged the port on my current sub and now know I'm a ported guy. Anyone else that has 4 subs in one room? I would love to hear how it is compared to one or two. Thanks

[Blu-Dog]

Originally Posted by qx56

Ok I forgot what this thread was about. I am convinced that 4 ported 12 inch subs tuned to 18-19 will make me happy. I plugged the port on my current sub and now know I'm a ported guy. Anyone else that has 4 subs in one room? I would love to hear how it is compared to one or two. Thanks

I'm outnumbered. I only have three, and frankly, I'd rather change where they're placed. I don't think they're optimum.

It's tough to focus when they're really pounding. As soon as I can get my eyes to stop jiggling I'll fool around with it.

[timcat4843]

Originally Posted by qx56

Ok I forgot what this thread was about.
I am convinced that 4 ported 12 inch subs tuned to 18-19 will make me happy.
I plugged the port on my current sub and now know I'm a ported guy.
Anyone else that has 4 subs in one room?
I would love to hear how it is compared to one or two.
Thanks

I started out with one subwoofer.
Then I went to two subwoofers.
Next I stepped up to four subs.

No contest, four subwoofers totally blows away having just one or two subs.
"Feeling" is believing!

[4Dblu]

I added 2 B-52 scoops in my basement to go along wit my 2 other B-52subs. check out my pics, ALL r 18 inches of pure glass breakin' BASS

[qx56]

So I thought I would see if anyone else has added exta subs since this post has died.

Sent from my HTC_Amaze_4G using Tapatalk

[StalkerVette]

Originally Posted by 4Dblu

I added 2 B-52 scoops in my basement to go along wit my 2 other B-52subs. check out my pics, ALL r 18 inches of pure glass breakin' BASS

BASSHEAD!!!!!

[StalkerVette]

Originally Posted by qx56

So I thought I would see if anyone else has added exta subs since this post has died.

I made the jump from two to four Mirage Prestige S-10's.

I thought I was happy with two................ I was wrong

[qx56]

Well I got a great deal on a epx2000. And getting 2 more 1260w's for Christmas so I will be ditching the plate amps and running the 2 front subs with one channel and the rear 2 with the other Channel. I should have them all going shortly after the first. I can't wait. Going from 400w to 2000w and a sub in each corner should be fun.

[onyxbfly]

I have 2 JBL W15GTI competition car subs in my HT Below reference levels they induce the oh sh!t FACTOR. My goal is to get two more for my HT and pop the screws from my neighbors drywall.

[qx56]

Nice. What amp are you using?

[onyxbfly]

Currently using an XPA 5 to power them. These subs are beast. They are rated at 800W RMS and 5000K peak. They are severely underrated. I am looking for pro amp. Something to do some serious justice. Still doing research....But then again that's part of the fun of this hobby.