Baffled by room acoustics

[SMM]

The more I read the less I understand!

Building a new HT in my basement. The room will be 19 x 14 with 86" drop acoustic ceiling. Planning for 7.1 speakers with towers as the mains and a fairly power sub as I love the bass. Planning for platered walls and fairly dense carpet on the floor, riser and front stage. How do I determine what if any acoustical treatments (i.e., bass traps) I'll need to get the best sound from my system and where is the best place to buy them. Thks!

 

[ScottMayo]

Acoustics is complex and there's a lot of advice out there, both good and bad.

Here's my take: just about any room needs to be treated if you want the best possible sound. All rooms except very large ones have bass problems, and very large ones have outright echo problems. And even a simple, rectangular room has a surprising amount of complexity when it comes to how sound moves and bounces.

The general rule of thumb is: put bass traps in all 4 corners; put flat traps at the first reflection points on (at least) the walls. That's not a complete solution, but it's often enough to make an unusable room usable. Curtains and rugs are usually NOT absorptive enough to achieve this.

If you have good gear, the very best improvement you can make to it, is getting an acoustic treatment plan drawn up for the room, and sticking to it. It's not cheap, but in terms of value for the dollar, it is far and away the most effective upgrade you can make. A mid-fi receiver in a properly treated room, with decent speakers, will outperform the very best megadollar super high end separate components system in an untreated space every single time.

 

[SMM]

If you have good gear, the very best improvement you can make to it, is getting an acoustic treatment plan drawn up for the room, and sticking to it. It's not cheap, but in terms of value for the dollar, it is far and away the most effective upgrade you can make. /I].

Any suggestions on where to go for an acoustic treatment plan and how much I should expect to pay. the room is 19 * 14 w/ 86" ceilings

 

[Glenn Kuras]

Scott is pretty much right on the money, but you may need a little more then 4 bass traps. It is tough to over do bass so as many bass traps as you can get away with is the best way to go. Or better said, as many as the wife will let you have.
You are right room acoustics is complex, all that funny math and people telling you a million different things, but it is not rocket science either.. So take your time a look for the best products for your room..

Glenn

 

[Glenn Kuras]

Any suggestions on where to go for an acoustic treatment plan and how much I should expect to pay. the room is 19 * 14 w/ 86" ceilings

http://www.sbrjournal.net/currentissue/articles/acoustics/Acoustics.htm

go here for a good plan..


glenn

 

[ScottMayo]

>go here for a good plan..

Hm. He gave up a crucial part of the midbass, and then he ended up employing electronic EQ and out of phase bass because he wasn't willing to put in the necessary amount of bass trapping. If you sit 3' to the left in that room, I'm willing to bet that nice flat curve he ended up goes straight to h?ll. However, he did get absorption on the rear reflection points, and that gets him big points, because a lot of people forget that wall.

And in fairness, in a room that size, it's hard to get things right, even with a full blown analysis, let alone by trial and error. 12'x12'x8' is every acoustican's worst nightmare. (Well, except for the phrase "My wife doesn't want me to move anything or put stuff on walls, and my budget is $150; what can I do?")

You could do a lot worse than that plan, but in a larger room I'd look for some discussion of diffusion, and more trapping.

In the end it comes down to how fussy you are and what you want to spend. HT tends to have a lot of bass ("It's my HT and I'll crank The Matrix up to 100db if I want to"). Unfortunately, bass trapping done right takes space - 2 traps angled in the corners is a start, but not usually the whole solution, if you want to get it right. The best advice is to set your budget in advance, know how much work you want to put in (trial and error is work), and know how to recognise "good enough." Only then can you select the compromises that are going to work for YOU.

 

[Glenn Kuras]

Heck yes he could have put in more bass traps, but for what he had and now what he has he is 300% better off..

 

[Ethan Winer]

Scott,

> he did get absorption on the rear reflection points <

Indeed. It pains me when I see someone with their couch right up against the wall behind them. Those are early reflections too!

> The best advice is to set your budget in advance <

Agreed. It's tough to avoid sounding like a used car salesman - "So, how much are you looking to spend on this?" - but that really is the most important first step.

--Ethan

 

[Glenn Kuras]

For the most part I seem to have people call and ask what they need and go from there.. Most people really don't know and what some ideas.. Then it is the old "ok let me talk to the boss and I will call you back".. I leave it up to them to do the hard sale, THE WIFE..

Glenn

 

[bpape]

Yes. His room is somewhat of a challenge. While I'd recommend more bass control before resorting to EQ, sometimes that's a necessity.

Realistically, when you look at the room and how bad it really could be, the results he did end up getting are pretty impressive.

 

[Buckeye_Nut]

For the most part I seem to have people call and ask what they need and go from there.. Most people really don't know and what some ideas.. Then it is the old "ok let me talk to the boss and I will call you back".. I leave it up to them to do the hard sale, THE WIFE..

Glenn

LOL

I bet you hear that a LOT!!

My wife always used to say that she would be happy with a 27" TV and their built in speakers, so lucky for me....... she isnt the Boss when it comes to HT projects.

Now that the theater evolution is nearly complete, she loves the results and changed her tune ......LOL