Room treatments, your experience

[SugarMedia]

Fire away...

fire away machine gun style if you will.

I am curious about this mirror theory and finding the optimal reflection points. How has this actually been scientficially calculated? Anyone know?

I'm not saying I'm a disbeliever, just looking for more, since this is a learning forum, right?


-SM

 

[IWalker]

I'll take a stab at this...

Sound waves (for this purpose at least) follow basic rules of trigonometry. If you treat the speaker driver as the initial point, and your seating position as the end point, it's a simple calculation to solve for the angles and legs of the triangle (where the point of reflection is the third point). All you need to remember is that the angle at which the sound hits the wall will equal the angle that it reflects at.

A mirror does just this, but with light, so you don't need to break out the tape measure and calculator to find out these reflection points.

Also remember that each speaker will have a first reflection point on each wall (and on the floor and ceiling as well)

Feel free to correct me if I'm wrong, or explain it better if I'm missing something.

-Ian

 

[jjqiv]

I just put the 16"x5' Tube Trap that I just finished building into my room. I concur, the affect is dramatic! I had to force my self not to put on another LP. I need to go to Home Depot to buy some more materials so I can build more traps.

I can imagine some of the comments that will come, like, what's with all the hot water heaters in your room? The size and color is almost exactly like my hot water heater. Hopefully the traps will look much better when I get a nicely finished outer cover of burlap around it. Right now the exterior is just some polyester batting.

Here are some pic's to give you an idea of the current look:

http://www.geocities.com/jonrisch/basstrap.htm

 

[DTB300]

I just put the 16"x5' Tube Trap that I just finished building into my room. I concur, the affect is dramatic! ..........I can imagine some of the comments that will come, like, what's with all the hot water heaters in your room? The size and color is almost exactly like my hot water heater. Hopefully the traps will look much better when I get a nicely finished outer cover of burlap around it. Right now the exterior is just some polyester batting.

Here are some pic's to give you an idea of the current look:

http://www.geocities.com/jonrisch/basstrap.htm

The Jon Risch Trap's have received a lot of good talk about them over at the Asylum.

BTW, there are sites where you can order some Guilford's of Maine if you want to cover them with something nice. You can also stop by your local fabric store and sometimes they have some nice fabric that passes sound through.

Dan

 

[Steve]

I just put the 16"x5' Tube Trap that I just finished building into my room. I concur, the affect is dramatic! I had to force my self not to put on another LP. I need to go to Home Depot to buy some more materials so I can build more traps.

I can imagine some of the comments that will come, like, what's with all the hot water heaters in your room? The size and color is almost exactly like my hot water heater. Hopefully the traps will look much better when I get a nicely finished outer cover of burlap around it. Right now the exterior is just some polyester batting.

Here are some pic's to give you an idea of the current look:

http://www.geocities.com/jonrisch/basstrap.htm

Where did you place the traps?

 

[jmschnur]

I have an unusal backdrop to my system since it was previously a closet. It leaves me with two middle (3' deep) partitions and cabinets above that are about 6.5 feet above the floor are 3 feet deep resting on the partitions . I have used Aurelex 2 inch wedges to good effect to cut off the early reflections from the extra "walls" in the center. I have done the same for the underhang below the cabinets that is behing my center speaker (Cinema i). I still have not yet done the under cabinets directly behind my speakers.

The speakers are 51" form the rear wall and 26" from the true side walls. Speakers are 6.5' apart and about 9' from the listeners.

In the back of the 5' wide center partition I have a 50" plasma TV. The cabinets above help skeep glare off the screen and the black auralex helps as well.

I use a Dalite pull up insta theater screen that gomes up for DVDs with a Nec HT1000 projector. This masks the center partition from the Vantage speakers as well and the sound as Robin suggested is a bit cleaner in this case.




I will post picrures once I am done with all the tweaking with the Dalite screen down for plasma TV viewing and up for DVD front projector viewing.

Joel

 

[jjqiv]

Where did you place the traps?

I have only made one trap so far. I put in the right corner, behind the right speaker. I want to make two more that are the same size to go behind the left speaker and in the left corner of the front wall. There is an alcove on the left size of my room.

In the rear of my room I have a wood stove on one side and a staircase leading to the upper level on the other side. No corner options their. I have possibly three or four spots I could place some smaller diameter tube traps

Also, I will try making/placing a wall panel in center of the rear wall.

Some DIY room lenzes are something else I could try.

 

[jjqiv]

The Jon Risch Trap's have received a lot of good talk about them over at the Asylum.

BTW, there are sites where you can order some Guilford's of Maine if you want to cover them with something nice. You can also stop by your local fabric store and sometimes they have some nice fabric that passes sound through.

Dan

I have already purchased some burlap. I just couldn't wait to try it out.

 

[jfm]

I use a Dalite pull up insta theater screen that gomes up for DVDs with a Nec HT1000 projector. This masks the center partition from the Vantage speakers as well and the sound as Robin suggested is a bit cleaner in this case.Joel

Thanks for sharing, Joel. We use the same pj; which Dalite do you use? I want to upgrade to a Dalite High Power. Ideally an electric would do well as I could then pull it up for music and have the center of the back wall treated, however the difference is $ is not small.

 

[Reverb2009]

Thanks for sharing, Joel. We use the same pj; which Dalite do you use? I want to upgrade to a Dalite High Power. Ideally an electric would do well as I could then pull it up for music and have the center of the back wall treated, however the difference is $ is not small.

If I build a dedicated audio room some day my plain is to have an electric screen with a micro perf material mounted in the ceiling set with a 12volt trigger. A click of a button and the screen will drop from the ceiling in between the speakers. My front wall would be acoustically treated with tube traps and the micro perforated screen would allow for the rear wave of the Logan’s to come threw.

On a side note, If I am not mistaken Da-lite does not offer an electric screen with the hi power material.

 

[jfm]

Joe, that's an awesome plan!

I have some space to mount the screen while still having the wall treated, though not with a big tube trap, just with a panel. Not sure about this, but don't micro-perfs lack the ability to produce the best image? If so, which brand? The only ones I'm looking at so far are the HiPower and the Vutec Silverscreen (which does cost a LOT more and would not allow for treating the center wall as it only comes in a fixed frame).

Yes, Dalite does have the HiPower in electric, my dealer is offering it to me at 3x the cost of the manual pull-down.

 

[JonFo]

Joe, that's an awesome plan!

I have some space to mount the screen while still having the wall treated, though not with a big tube trap, just with a panel. Not sure about this, but don't micro-perfs lack the ability to produce the best image? If so, which brand? The only ones I'm looking at so far are the HiPower and the Vutec Silverscreen (which does cost a LOT more and would not allow for treating the center wall as it only comes in a fixed frame).

Yes, Dalite does have the HiPower in electric, my dealer is offering it to me at 3x the cost of the manual pull-down.

Joe, jfm, I have a microperfed screen (a 100" Steward StudioTek 130 MP) in a fixed mount. The imaging through it is decent enough for movies.

The biggest issue in my book is the reflections the back of the screen causes, which can ‘smear’ the sound a bit, losing a bit of dialog intelligibility.

See pics and frequency / waterfall plots of what my current Logos centers does behind my perforated screen over in my thread about my new ‘Extreme’ center channel speaker project.

As for what materials would work best, I’ve read a lot of good things about the ScreenResearch ClearPix2 material.

Here is a very good article on audio performance of the Stewart, Drapper and Screen Research materials. Includes measurements and it tags the ClearPix screen as the best performer.

Anyone want a nice microperfed Stewart 100” screen?

As for treatments, I also treat the front wall with Auralex and RPG absorbers. I had tried a dispersion block in the middle, but that affected dialog too much.

I recommend absorption between the front L/R and around a center speaker.

 

[jmschnur]

"Thanks for sharing, Joel. We use the same pj; which Dalite do you use? I want to upgrade to a Dalite High Power. Ideally an electric would do well as I could then pull it up for music and have the center of the back wall treated, however the difference is $ is not small. "

I use the Da Lite Insta Theater 80" 4x3. I can not put a pull down in the ceiling easily since the rafters go the wrong way. The Dalite screen is someting called "wide power" and works quite well in our setting. I have looked for "better" pull ups but have not found any so far.

Joel

 

[Reverb2009]

Joe, that's an awesome plan!

I have some space to mount the screen while still having the wall treated, though not with a big tube trap, just with a panel. Not sure about this, but don't micro-perfs lack the ability to produce the best image? If so, which brand? The only ones I'm looking at so far are the HiPower and the Vutec Silverscreen (which does cost a LOT more and would not allow for treating the center wall as it only comes in a fixed frame).

Yes, Dalite does have the HiPower in electric, my dealer is offering it to me at 3x the cost of the manual pull-down.

Sorry about that, I got mixed up; they don’t offer a tensioned electric screen in the high power. Sorry I had a brain fart.

As for the best micro perf screen, I can’t find my notes right now, but I had it narrowed down to two screens, one was the best bang for your buck microperf, and the other was the best you can buy microperf for both audio and video performance. I will post my choices when I find my notes.

Yes, the tinny holes in the fabric can degrade the video quality, and if you sit too close to the screen, the holes can become very visible.

As for silver screens, the Da-Lite hi-power is considered the best bang for your buck silver screen and the Silver Star is considered the best money can buy.

Here is a comparison thread that may help you.
White, Grey, or Silver - A Review
http://www.avsforum.com/avs-vb/showthread.php?t=658034

 

[jfm]

What I would like to further explore:

1. Absorbers in the center of the wall behind the front speakers. Any experience with this from anyone? I have a front pj and I am thinking of an electric screen to replace my pull-down, if this center absorption is promising.
2. Adding tube traps in the rear.
3. Adding diffusors along the side wall.

Previously, I only had bass traps at the corners and combo absorbers-diffusors behind each main speaker. I've then installed tube traps in the rear.

Recently, I've finally treated (a) the side reflection points and (b) the center of the front wall in front of my pj screen, with the help of a friend who made these for me, following ASC design principles.

Picture of (a), on top of the custom software cabinet, which is designed to also act as a diffusor. There are parallel panels on the right side. Room is dedicated and symmetrical.


Picture of (b). The panels hang on rollers, so they can glide into the center for audio and out of the way for video. The screen (DaLite High Power) rolls from under an extended cornice, which hides both the screen case and the rollers and channels for the new panels.


Impressions:

- Treating the side reflection points had the curious effect of making the room sound cozier, as if containing the sound a lot better. Instead of expanding the stage as I first expected they would, the treatments actually deepened it and made it more intimate. (I'm studying the posts about Dan's room with interest, as Dan (DTB300) has treated his whole room and it seems he's reached the same effect, that of a small club.)

- Instruments at the sides of the stage came alive. Before the sound splashed around a greater space; now they're tighter. Makes it easier to follow the players who are playing more softly than the others -- and isn't this one of the rare talents of ML speakers, that you can follow musical lines of different musicians playing together but at different volumes.

- Treating the center of the screen for audio solidified the center image and deepened the whole stage. Drum kits are now further back, and they snap and sizzle more. Plus, the center treatment reduced the sensitivity of listening position height. Before, any slight movement sitting up and sitting forward caused big changes in the stage and solidity of instruments. Bass is helped too, which was a pleasant surprise.

- Overall, more details are apparent, which is what one might expect. The room is energized more easily. I had a slight problem with upper midrange glare that's now jsut about gone. My family members also tell me I listen a lot more loudly now - reduced distortion maybe? Yup, I'm happy.

Thanks for reading!

 

[Pcar928fan]

Impressions:

- Treating the side reflection points had the curious effect of making the room sound cozier, as if containing the sound a lot better. Instead of expanding the stage as I first expected they would, the treatments actually deepened it and made it more intimate. (I'm studying the posts about Dan's room with interest, as Dan (DTB300) has treated his whole room and it seems he's reached the same effect, that of a small club.)

- Instruments at the sides of the stage came alive. Before the sound splashed around a greater space; now they're tighter. Makes it easier to follow the players who are playing more softly than the others -- and isn't this one of the rare talents of ML speakers, that you can follow musical lines of different musicians playing together but at different volumes.

- Treating the center of the screen for audio solidified the center image and deepened the whole stage. Drum kits are now further back, and they snap and sizzle more. Plus, the center treatment reduced the sensitivity of listening position height. Before, any slight movement sitting up and sitting forward caused big changes in the stage and solidity of instruments. Bass is helped too, which was a pleasant surprise.

- Overall, more details are apparent, which is what one might expect. The room is energized more easily. I had a slight problem with upper midrange glare that's now jsut about gone. My family members also tell me I listen a lot more loudly now - reduced distortion maybe? Yup, I'm happy.

Thanks for reading!

NICE REVIEW! Someday I hope to use that information to build my own dedicated HT room!!

 

[Dreamer]

I've noticed that a lot of folks here who are doing room treatments are going for a sort of "studio acoustic" atmosphere in their listening rooms. Having played sax in jazz bands in my high school and college years, I always found "dead rooms" really hard to play in, because they didn't really let you hear all of what was going on. At least for me, playing in a small jazz combo, I got cues from all sorts of things, not just the sheet music. I would listen for the trumpets to flick their valves, signalling they were going to come in, or some other such micro-harmonics. And to be honest, as a musician, playing in a slightly live (but well-controlled) room can be a LOt of fun, because you can actually play with the acoustics a little, and cause all sorts of interesting harmonic oddities. Plus, it makes it easier to hear yourself as a performer, if the room i sa little live.

Anyway, as an audio nut these days (I still pick up the sax now and then, and blow the dust out, but no longer play in bands) I find that my opinion about "dead rooms" is still the same. I prefer live rooms. There is no disputing that some of the rooms I've heard (like Dan's) which are SERIOUSLY acoustically treated, do produce a really nice sound, especially if you've got bigger speakers in a small, hard room (concrete, or block basement, especially).

But I will admit that I fall in the "live room/spot treatment" camp, a-la Michael Greene. I used to have a full set of his "Room Tunes", which are little triangle shaped pillows that you tack up in the wall/ceiling joints of the room (and also square ones that you use for side-wall, ceiling, and back-wall reflecions). These little pillows really go a long way to even out bass without killing the mids, and can actually tighten up the bass and mids by cancelling (or at least controlling) standing wave reflections in live rooms. The great things about Room Tunes is that 1) they are relatively unobtrusive, and can be used without making your living room look like a recording studio, and 2) they let you keep your listening room "live" and yet not be ringy or brassy.

You can get them in a number of colors (to closely match common wall paints) and they are pretty reasonbly priced.

I think my original set of RoomTunes got tossed when I moved last fall, but luckily, I'd dissected them a few years ago, and know how to make them. I have a sewing machine and I know how to use it...

Now all I need to do is make a set and get to tacking them up. Hopefully my Sweetie won't finde them too objectionable. If she does, I suppose could mount them with velcro, and take them down when I'm not doing "critical listening"...

--Richard

 

[Rich]

I agree with Richard that it is important when you are acoustically treating a room that you don't deaden it too much or you will reduce the vitality of your sound. I think there is probably a fine line between controlling reflections and trapping bass on the one hand, and over-deadening the sound on the other.

I think it is helpful acoustically (although not necessarily esthetically) to have more, narrower panels on the sidewalls that are spaced apart, leaving a fair amount of drywall surface area to pass some reflections and keep the liveliness intact. Also using panels that perform a mix of absorption and diffusion on the sidewalls is probably a good idea.

Bass traps in the corners, absorption in the middle of the front wall, and diffusion on the sides of the front wall and along the rear wall, and I think you end up with a nice room where reflections and standing waves are tamed, but liveliness is not lost. Of course, these are generalities and every room and every application is somewhat unique. That's why it is a good idea to get some professional advice regarding your particular situation if you can do it.

I have to agree with sentiments that have been expressed before that most of us spend way too much on really high quality equipment to spend so little on acoustic room treatments. There is a lot of bang for the buck to be had from room treatment in terms of system sound.

 

[DTB300]

I agree with Richard that it is important when you are acoustically treating a room that you don't deaden it too much or you will reduce the vitality of your sound. I think there is probably a fine line between controlling reflections and trapping bass on the one hand, and over-deadening the sound on the other.

Bass Trapping "usually" does not equate with deadening the sound as it depends on the trap and its absoption properties. Usually what occurs is once you have proper amounts of bass trapping in your room, the mids and highs start to become more detailed and present in the music you are listening too. That boomy or uncontrolled bass reflections in your room is no longer covering up other parts of the music.

I think it is helpful acoustically (although not necessarily esthetically) to have more, narrower panels on the sidewalls that are spaced apart, leaving a fair amount of drywall surface area to pass some reflections and keep the liveliness intact. Also using panels that perform a mix of absorption and diffusion on the sidewalls is probably a good idea.

1st reflection point panels are generally thinning in build than your corner bass trapping. Look at the products from Ethan Winer and Glenn Krauss with their respective companies (Real Traps & GIK) and you will see them. Even the 2 or 3" panels from Auralex work great for first reflections point control.

In regards to absoption and diffusion, most have found the absoption for bass in the corners from floor to ceiling, then absorption at 1st reflection points for reducing comb filtering affects, and finally diffusion behind the seating position. This type of setup you will find in more rooms than not. But again each room is different and dealing with them is greatly assisted by working with Ethan or Glenn.

Bass traps in the corners, absorption in the middle of the front wall, and diffusion on the sides of the front wall and along the rear wall, and I think you end up with a nice room where reflections and standing waves are tamed, but liveliness is not lost. Of course, these are generalities and every room and every application is somewhat unique. That's why it is a good idea to get some professional advice regarding your particular situation if you can do it.

Rich...You are correct that most of these comments we have made as "generalities" and each room/setup are different and may need a different approach. Some may prefer diffusion behind the speakers, so absorption. But the bottom line to better sound to start is controlling the low end in ones room.

I have to agree with sentiments that have been expressed before that most of us spend way too much on really high quality equipment to spend so little on acoustic room treatments. There is a lot of bang for the buck to be had from room treatment in terms of system sound.

The addition of room treatments in my setup had made an enormous improvement in my sound for very little money.

What I would suggest to those thinking about getting into this area of audio. First pickup a product like Room EQ Wizard or ETF, and get a simple microphone like the Radio Shack SPL Meter (a true microphone can be purchased especially if you are looking at the entire frequency range and not just the low end).

Do some initial measurements of your room, starting with the Bass and its response, and see where you are. And like me, you will be very surprised at the type of response you are getting seeing many peaks and nulls from 20 - 200Hz in your room - this is very typical.

Then look at either Real Traps or GIK Acoustics as your prefered products choice. Contact Ethan or Glenn, depending on the company you choose, and start going over what you have and how to attack it. Note, you will also need a drawing of your room for them to see too.

Remember you can start small with just a couple of panels, and slowly but surely address and resolve the issues with your room.

Dan

 

[Rich]

Great points, Dan. I especially like the fact that you point out that it doesn't have to be expensive to do a little acoustic treatment. There are some great products offered for reasonable prices, plus there is a lot of info. out there for DIY'ers. The impacts on the sound quality of your system will not be small.