Room treatment: How do I know if I need it?

[mpompey]

I'm assuming that unless your HT is designed from the ground up, and your house is built around it, all rooms could benefit from some kind of treatment. I've got a BFD on my sub and have tamed out the peaks in response, but I've got a couple of dips still. I'm not sure if these would respond to room treatment or not.

I don't know how to answer the question if my room needs treatment, or if it is overkill.

How do I begin?

 

[avaserfi]

Have you tried moving the sub around to as many possible locations in your room? That is the first step along with changing your phase in getting a flat response for your woofer.

In general the worst areas for bass response acoustically are room corners as thats is where bass waves tend to build up so dealing with that via treatments would probably be your best bet.

A room diagram would help very much .

 

[mpompey]

I'll post a google sketchup image of my room setup, and a graph of my bass response later tonight.

 

[Glenn Kuras]

You need room treatment, end of story.

All kidding aside room treatment is one of those things that most people really have no clue about. Not that they don't understand it, but because they have never experienced how AWSOME your system will sound with the room treated properly.
EQ is not a bad thing (well I don't like it but some people do) but it is never going to solve ringing in the room and that can cause more problems then just a flat response. Also like you said you can never solve the nulls.
When someone with treatment reads a post like yours it is like you asking "I have a car, do I really need wheels for it?"

Glenn

 

[mpompey]

Glenn, thanks for the reply.

I'm sure my room needs some type of treatment. But where do I start? What questions should I ask to get me looking at the right options. I also know treatment can be an expensive undertaking depending on how far I want to take it. I don't know enough to even figure out whether or not it is an expense I wand to undertake. Some of the questions I have right now are:

Do I need diffusers/ absorbers? How much of each?
Do I have to completely cover all walls? What about corners?
My current HT is in the finished basement and has a drop ceiling. Do I need to replace those acoustic panels or can they stay in place?

I guess I need a treatment primer. Something to get me pointed in the right direction.

Any help would be appreciated.

 

[Savant]

You need room treatment, end of story.

End of Glenn's story maybe...

My initial piece of advice would be to ask mpompey how the room sounds now? Flying in the face of conventional wisdom (and quite probably completely contradictory to some of the things I've written in the past! ), I don't believe all rooms need acoustical treatment. From a physics standpoint, this is more or less true. But there's more to room acoustics than Hertzes and decibels and squiggly-line graphs. If the room sounds good to you, then you may not need to do a thing.

But, as Glenn has pointed out, if you want the most bang-for-your-buck out of the system, then treatment is a prerequisite - arguably more important than any other HT component. And, if you're starting from nothing, good acoustical treatments will usually make a much bigger difference to the sound relative to, say, upgrading a receiver.

EQ is not a bad thing (well I don't like it but some people do) but it is never going to solve ringing in the room and that can cause more problems then just a flat response.

This point is arguable, depending on how broadly we define "EQ". Some digital room correction (DRC) tools can address the transient problems in a room ("ringing"). IMO, not as well as good room design and acoustical treatment in most cases. But sometimes, a little "tweak" from a good DRC is all that's needed...

When someone with treatment reads a post like yours it is like you asking "I have a car, do I really need wheels for it?"

To which I would reply, "Probably. But does the car meet your needs without the wheels?"

 

[gmichael]

Here is a sight worth poking arround in. http://www.rivesaudio.com/software/softframes.html

They have a few areas with free tips, as well as trying to make a buck off of you in other areas.

 

[bpape]

Glenn and Jeff are both right. I'll just follow up with:

Do you NEED it - that's your decision.

Have I ever seen a totally untreated room that wouldn't benefit from it and sound better? No.

Even with a room designed from the ground up, the internal space still needs to be tamed. One can do a lot with speaker and seating locations, room dimensions, and a but of JUDICIOUS EQ on the sub. However, none of those things will bring decay times in line, tighten the bottom end, improve the imaging, make the dialog clearer, etc.

Just my 2 cents.

Bryan

 

[Glenn Kuras]

To which I would reply, "Probably. But does the car meet your needs without the wheels?"

Well if all you want to do is sit in the driveway then yes, but if you want to go crewzzing then YOU BEST HAVE WHEELS.



Glenn

 

[Glenn Kuras]

"I'm sure my room needs some type of treatment. But where do I start?"

Well it sounds like to me you have started. We do have some education things on our website. Also you can gain some things from http://www.ethanwiner.com/acoustics.html
Also there is a nice case study at http://www.sbrjournal.net/journalsite/archives/acoustics/Acoustics.htm showing how room treatment can help.

"What questions should I ask to get me looking at the right options."

Well posting your room size with set up would help. Pictures and a drawing are also very helpful. If you plan on just buying the products then I would contact the company and have them do all the work for you. Most good acoustic companies can give you guides on the right products and set up.

"I also know treatment can be an expensive undertaking depending on how far I want to take it."

You would be surprised how much room treatment cost vs. all the other things in your room. Some rooms we have done cost as little as $800, but some could cost over $3000. It just depends on how far you want to take the room.



"Do I need diffusers/ absorbers? How much of each?
Do I have to completely cover all walls? What about corners?
My current HT is in the finished basement and has a drop ceiling. Do I need to replace those acoustic panels or can they stay in place?"

We would need to know your set up before answering those questions.

Glenn

 

[mpompey]

Here are pic and a rough schematic of HT area

Thanks for the input so for, I've done some research in the mean time regarding room treatments, absorbers, diffusors, bass traps etc. While I'm no expert I understand now what each is supposed to do.

I've uploaded two pics of my theater, as well as a schematic with dimensions of the downstairs area. One picture is taken from the middle of the left wall looking toward the screen. The other is taken from the right speaker looking into the theater area and office space in the back.

I hope this helps.

 

[bpape]

Are those Ohm F's? I haven't seen a pair of those for a long time. Nice speakers if you give them some room to breathe.

Your setup looks like it might be kind of tough to get much bass control in there. Most likely, I'd try to fill above the drop ceiling with insulation to get some additional broadband control since you can't play with a lot of your corners.

The other thing I'd do is get some panels at a minimum on the right wall to help with boundary bass issues and make the whole wall appear acoustically farther away so it's effectively it's more symmetric.

Bryan

 

[mpompey]

Bryan, how much insulation would you recommend above the drop ceiling? Would I be in danger of over-dampening the room?

I was also considering moving the Ohm's upstairs and replacing them with Axiom M80s and a separate amp. Do you think that is overkill for that space? Or should I go with the 8 -ohm Axiom M60 and run it off the current receiver?

I can't make up my mind. I'll probably be in that space for another 4 years.

 

[Grantc79]

You need room treatment, end of story.

All kidding aside room treatment is one of those things that most people really have no clue about. Not that they don't understand it, but because they have never experienced how AWSOME your system will sound with the room treated properly.
EQ is not a bad thing (well I don't like it but some people do) but it is never going to solve ringing in the room and that can cause more problems then just a flat response. Also like you said you can never solve the nulls.
When someone with treatment reads a post like yours it is like you asking "I have a car, do I really need wheels for it?"

Glenn

Pretty much, if you look down a bit in this forum area you will see where I made treatments for my place. The sound quality improvements it gave me were insane.

I also built some basstraps out of the same exact materials in about 45 minutes which did wonders as well.

 

[bpape]

The increas in damping of the upper mids and highs by doing above the ceiling is going to be basically zero. It's already there with the tiles. All we're doing is broadening it.

Considering that we really can't do a lot else in the room other than maybe a little on the right wall, the last thing I'd be worried about is overdoing it. I'd at a minimum do the entire cavity height around maybe 2' of the perimeter all around. If you can do more, especially right over the seating, it certainly won't hurt.

Personally, I think the Axioms will work better in that room. The full 360 degree ratiation pattern of the Ohms has got to be causing a ton of problems in that corner like that - and that close to the front wall.

Bryan

 

[jaxvon]

Omnipolar speakers like the Ohms need special considerations when treating acoustics. First, they should be farther away from the wall. Second, you *want* a first reflection, as well as a backwave reflection. These will take advantage of the wide dispersion and create a much more realistic sound. Third, you should look at using treatment to prevent the L&R channels from interfering between each other. To be honest, I would suggest PMing WmAx, as his mains are roughly omnipolar and therefore has a very specific room treatment plan in use for them.

 

[mpompey]

Jaxvon, I PM'ed WmAX to get his thoughts. But from everything I've heard so far, I should probably wait on the mid-high treatment on the walls until I've replaced the Ohm's with the Axioms. I don't want to make the theater sound worse by doing this.

I'll probably start with bass traps in the two rear corners.

 

[mpompey]

Bryan, what kind of material would you recommend above the tiles? I'm thinking fiberglass because it is fire resistant. But I would rather not deal with fiberglass dust while putting it up there. That stuff just makes me nervous.

Is there some kind of fire resistant foam I could use?

 

[WmAx]

I did respond to your PM. However, I did not see this thread before I replied. I do not see how this room can be useful for an omnipolar speaker without some serious compromises. Your current set up with those omnis would result in poor quality sound. Based on your current set up, I would recommend that you get monopoles and treat the room as well as you can.

-Chris

 

[mpompey]

Thanks for the info. I'm going to put your recommendation on some prescription paper and show it to my wife.

"See here, the doctor says I need to get some more speakers, soon! Or I might suffer brain damage!"