Ibelieve the last link I provided talks about foam products and how they are really not worth the price because they are not even close in low frequency absobtion compared to DIY traps that can be built for $19 a piece.

Thanks man, I found some of those links using Google, I'll have to check the others out. I think your 1st and last link are the same.

I really only have the two corners behind the left/right mains and sub. That area is where my screen sits back about 6feet. Then it opens up into a much larger room. My surrounds and projector are near a boxed in area for my duct work. I was thinking about putting something up there facing back towards the mains. This treatment stuff is new to me, however, I don't want to go overboard and ruin the sound which sounds great now. If you followed my first attempt at graphing my room with the realtraps cd, I had some big ups/downs....

I'm confused.

I'm not trying to sound negative about the whole thing, but on the provided link "I almost went with this one" there is a before/after graph at the top of the page. Clicking to take a better look, I just don't see the results that the author (near the bottom of the page) calls:

"In a word ASTONISHING! The once muddy room now sounds fantastic! I can hear pristine mixes, much sharper sound stage ,clear imaging, much tighter bass lines. My studio has never sounded better! I feel like I'm finally getting to hear what my studio equipment and monitors can do."

Not to sound like a jerk, but after installing what the author says is "7 Bass Traps, 2 mid/high Traps, and 2 "Super Chunk" traps" I would expect results that are better than a lower-level virtual mirror of the original measurements.

I do believe in the idea of acoustic treatments and have primarily avoided trying it only because I'm already short on space. But the results that he's touting don't look very impressive to me at all!

Can someone else look at the graph and tell me....am I missing something?

No, that guy sniffed too much fresh foam, I think.

I'm with you Mark. To me, the graph still has the same dips and peaks, everything has just been dampened.

I have also been researching some treatments for my room. Don't know what just yet (DIY or professional), I am trying to decide what is "needed" without absorbtion overkill.

I'm thinking some absorbtion panels up front at the 1st reflection points between the speakers and the listeners. For me this is just 2 panels, unless I put 1 or 2 more on the ceiling. I have decided not to do any panels in the back of the room (between the side and back surrounds). Here you don't want absorbtion of the mid and high frequencies, but rather diffusion for a more spacious surround effect.

There sure is a lot to understand about room acoustics when you are new to it. I have done a lot of reading and still feel confused

>>I'm with you Mark. To me, the graph still has the same dips and peaks, everything has just been dampened.

I think that is what you would expect from good room treatments. You can't fundamentally change the peaks and dips except by (a) changing the dimensions of the room, (b) changing the speaker placement relative to the walls, or (c) sitting in a different place in the room relative to speakers and walls.

What bass traps can do is make the peaks smaller so you get a flatter frequency response -- when I look at that graph I see most of the peaks reduced by ~8 dB (which is a fair amount) and some reduced by 10-12 dB. I bet that room would sound MUCH better with the bass peaks taken down 8-12 dB.

Also, a frequency response graph only shows the most blatant changes. You need something with a time element, like a spectral decay graph, to show the reduction in echo at different frequencies, aka improved "tightness".

Having said that, the only "treatments" I have had time for in my new house are a borrowed rug and a pile of moving blankets in each corner (hey, I had to put them somewhere ).

Thanks Bridgman!

Interesting information overall....thanks for the input everybody.

>>>> I have also been researching some treatments for my room. Don't know what just yet (DIY or professional), I am trying to decide what is "needed" without absorbtion overkill.

This was my original thought process as well Dave, start here and then go from there.

I make my fat-ass dog sit in the corner of the room when I'm doing critical listening.

Has anybody used products from HSF Acoustics? Prices seem to be very reasonable and there before/after sound clips show amazing difference when applied. I see they also have an Ebay store.

http://hsfacoustics.com/studiopacks.htm

The only problem I can see with the HSF stuff Randy is trying to get the things to blend with the room and decor, which I understand can be a problem in most home environments. Some folks like the bold 'engineered' look of these types of panels, which look great in some environments, personally I'm looking for something a little (lot) laid back.

On another note...

Last night while listening to music in 2 ch stereo I noticed the left front main seemed to have a little less volume than that of the right front main, maybe even a little (very minute) flatter sound and was thinking how I may need to recalibrate. Just in a matter of minutes my wife walked in and closed the plantation shutters that are on the window within the first reflection point of the left front speaker and I couldn't believe how the speaker came back to life ... I'm assuming the shutters, while open act as a diffuser on that particular speaker while the right main is getting full reflection from a solid wall.

Does absorbing panels, traps and diffusers tend to flatten the sound as these shutters seem to be doing? Also, sometimes I wonder if a little reverberation and reflection isn't necessarily a bad thing, especially in a pretty decent acoustic room ... which I believe *luckily* ours seems to be.

Good questions Rick, for me I don't think the HSF stuff would look that bad. My back screen wall is painted flat black and my side walls ceiling are painted a dark navy blue. Since this room is a dedicated HT room, like a theater, it might work for me.

The sample audio clips are amazing what they did for the guitar and drum. I'm going to try the real traps test tones one more time with the 500 in the corner and compare to the other locations. Who knows, maybe I'll make some DIY treatments to see what happens, might be hard to beat HSF prices though.

I'm sure the 4' x 8' pool table I've added will change things also.

>>Does absorbing panels, traps and diffusers tend to flatten the sound as these shutters seem to be doing?

Sort of, but in your case I think the issue is that you need to recalibrate by a few dB when opening and closing the shutters, or at least calibrate with them set to whatever you use when listening. I noticed that between my left and right surrounds (M2s right now; my QS8s are out for extended audition) I had to bump one side up by 4 or 5 dB because it was in the open while the other was a couple of feet from a wall.

Randy, the good news is that you have a new degree of freedom -- you can experiment with changing your room acoustics by moving the pool table around

Good thing I put "moving buddies" under each leg.

>>I put "moving buddies" under each leg.

Geez, remind me not to help *you* move. Didn't their families come looking for them after a couple of days ?

I just read an interesting article on room acoustics and thought I would share the link. It aims to provide a basic understading of the various priciples involved while covering some examples of problematic rooms/objects, and tips on materials and placement

The author mentions the use of plants and actually includes a table of absorption coefficients for several species.

Link.

>>> Good questions Rick, for me I don't think the HSF stuff would look that bad. My back screen wall is painted flat black and my side walls ceiling are painted a dark navy blue. Since this room is a dedicated HT room, like a theater, it might work for me.

Actually I believe the HSF panels would go with your room very nice Randy, and they do seem to be priced right ... they'll look really nice around the pool table, uh huh!

Rick, the more and more I read about these GIK products, I'm becomming interested. hmmmm

From one SRV fan to another, check these sites.. Ethan Winters has quite a bit to read, but for those looking for the magic behind the curtain, you will find quite a bit of it there..
http://www.musicplayer.com/ubb/ultimatebb.php?/ubb/forum/f/26.html
And another:
http://forum.studiotips.com/index.php
And, for those that want to come all the way over the dark side, http://ibsubwoofers.proboards51.com/index.cgi
...
And yes, you can dial in the amount of acoustic treatment you want.. Home theaters tend to be more on the dead side, as opposed to studios and music only rooms, which favor the livelier brighter room..
Oh, the older style wiremesh/box/compressed fluff has been pretty much replaced by the factory compress 700 series style, mineral wool, and acoustic cotton..
Lots of good reading, hope it helps..

Looks like GIK is offering a 10% discount over on AVSforum on their new corner Tri-Traps. When ordering on their website from now until 7-20-2006, use coupon code "AVS" and you'll get the 10%. So far I have not found another Bass Trap with these impressive stats, or approved by Riverbank Acoustical Laboratories (RAL). This is very tempting.

The ONLY TRI CORNER Trap on the market! Until now, acoustic enthusiasts had to make do with foam wedges for corners which are unattractive and far less efficient in sound wave absorption than acoustic panels. BUT NO MORE! Our dedicated sound engineers are proud to introduce the GIK TRI-TRAP. The Tri-Trap, like all of the GIK bass traps, was lab tested at the prestigious Riverbank Acoustics Laboratory and the results were amazing. The Tri-Trap has true effects at 50 Hz and below. The Tri-Trap has been effectively designed to absorb more low end, but also does an excellent job of absorbing the high end, creating smooth sound absorption from 50 Hz to 5000 Hz. Installing our Tri-Traps will result in a beautifully balanced room that will suit even the most critical listener.



http://www.gikacoustics.com/product_info.html

Randy I went ahead and ordered a pair of the Tri-Traps and did get the 10% discount using the 'AVS' coupon code ... after reading a couple of reviews (including Audioholics) I concluded it's worth a try, so whenever they arrive I'll share my thoughts.

Those look pretty sharp... like Ethan's "Soffit Traps" but designed more for wall corners than ceiling corners. You realize everyone is going to want "before and after" response graphs from you, right ?

I'd love to graph the room John, I'm just not sure how to go about doing this ... keeping in mind that PCs are far from my expertise.

Audibly, in the sweet spot there seems to be just a very minute loss of bass as opposed to the rest of the room, even just standing in the sweet spot I can hear a very slight difference. In my 25' x 14' room I have the couch 9' from the back wall, which going by the 38% rule is where it should be positioned for the flattest response ... I'm thinking the ceiling may be causing the oh so slight bass loss and am hoping the traps may tighten and tame the bass just enough to change that slightest difference. I've tried moving the couch forward and backwards and this position seems to produce the best overall sound.

Luckily I believe I have a very good acoustic room overall but I'd like to maybe tighten the bass up just a very small amount and I believe the traps may help. And also believe me whenever I tell you that I typically don't fall for the snake oil stuff but have read enough to believe it's worth a try.

Now, how do I graph the room again?

>>Now, how do I graph the room again?

Personally, I would PM either Randy or Mark and say "so, like, wanna come over and listen to my system ?"

Iowa <-> New Hampshire -----> Florida? I dunno John, I just don't know ... I'll give it a try though.

D'oh !!

Um... (thinks for a minute) well, duh, obviously I meant invite them in the winter when it's bitterly cold in both places and Florida doesn't seem so far away. Yeah, that's what I meant !!

It's not too bad, really, although it is kind of mind-numbing (although not as bad as archaeology). You can download a series of test tones from RealTraps and burn them onto a CD so that hitting "next" moves to the next frequency. Then you just set up the SPL meter on a tripod in a reasonably readable position, step through the frequencies on the CD, and record the SPL meter reading at each step being careful to stand in exactly the same place every time so as not to muck up the readings. It's easier if you have a "reader" and a "writer-downer".

Here are the instructions from the Rives CD :

http://www.rivesaudio.com/files/TestCDinst.pdf

The other option, also from Rives I think, is a little kit you hook up to a PC your HT aux inputs. You push a key, it makes some wierd noises, digests the results for a minute, then spews out not only frequency response charts but spectral decay graphs for all the frequencies, eg "the room is too absorbent at most frequencies but has an evil echo at 500 Hz".

http://www.rivesaudio.com/software/testkit.html

For the HT owner who has everything -- including crappy acoustics

Rick, that is great, I'm trying to decide what to do...the tri-traps are more expensive, but seem to have much better absorption compared to traps that span corners. Everything is better than foam, based on my recent studies. If the trap is made from rigid fiberglass like owens corning 703, or using mineral wool board (cheaper) your good to go. The 440 and 442 (1st/2nd reflections) are much much cheaper.

I've learned tons from the Realtraps website. The videos showing how nulls can exist within 1" is amazing. Ethan's HT room is killer with 39 traps. I've also learned that what people say about HT being differant than music for treatments is not true, the main goal is to achieve a flat as possible frequency curve. Reducing ringing, combing is also very important. You can't do that with just furniture, drapes, etc...

I'm also tossing around the idea of building my own. It might be cheaper than building them. Insulationworld.com has good prices on Owens Corning Mineral Wool board.

That would be great to see your before and after results. Thanks for your help via PM's, I'm excited to start my own DIY traps.

I found a local insulation supplier in my home town that had the OC703 for about $9 sheet, pretty cheap compared to the online sellers and that there is no shipping charges. I purchased enough to start with 2 8ft SuperChunk Bass Traps for my front wall. Royce, thanks for the Bryan's referrel at SensibleSound. Him and I talked for about an hour today and he was very helpful and knowledgable on this subject. If only I could have the knowledge that Bryan or Ethan Winer have in this area, it would be scarry.

>>If only I could have the knowledge that Bryan or Ethan Winer have in this area, it would be scary

I ran across a quote a while ago talking about how to make one of those wonderfully green English lawns...

"start with any green space, then seed it and roll it for 150 years..."

I think it's the same with acoustics. These guys have spent 20+ years implementing room improvements then trying to figure out why the heck "it didn't work like it was supposed to...". The rest of us just try to understand and apply their comments and advice to our environments.

Just think about that scene from "silence of the lambs" where the victim is fumbling around in pitch blackness and the bad guy has night vision goggles.

We are the victim ;(

Very well put John, I'm sure you have read this article by Ethan from RealTraps, but I'll post it for the others, basically an Acoustic Treatment 101. Yes everyone, acoustic treatments are not just for music/recording studios, the same rules apply to a HT environment.

http://www.ethanwiner.com/acoustics.html

Getting up early to start building my superchunk bass traps, keep ya all posted. We've had really humid temps lately so want to get done early so I don't sweat to much.

The 17" x 17" x 24" Owens Corning 703 superchunks are in place and fill my front left/right corners. Hope to have the cloth frames completed soon to hide the rigid fiberboard.

No problem - can't wait to see what those Super Chunk's look like. Whose "recipe" have you decided to follow?

After talking to BrianP over the phone from Sensible Solutions, and getting some feedback on Ethan's forum thread, I ended using OC703 but also used this guide you gave me http://www.radford.edu/~shelm/acoustics/bass-traps.html from Steven Helm.

Brian said I would get much better results using the 703 superchunks compared to mineral wool or even straddling the corners with 4" material. He also gave me suggestions on treating the rest of the room, although I'm going to do a little bit at a time.

SirQ,
The frequency graphs on that last link did not lead me to believe this fellow's bass traps were particularly effective at doing much of anything except changing the frequency response, slightly.
If the goal there was to curb the peaks and increase the dips, then...


If the goal is to flatten that bass area, a Berhringer unit or something similar would be far more effective per dollar spent.

>>The 17" x 17" x 24" Owens Corning 703 superchunks are in place and fill my front left/right corners. Hope to have the cloth frames completed soon to hide the rigid fiberboard.

Forget the frames. Does it SOUND any different ?

Graphs, we want graphs

I'm with bridgman.
Show me the graphs!

Speaking of graphs, it is on my agenda to graph my own media room soon. Working on getting the recording software and a decent mic.

I actually see a good improvement to Mr. Helms results, the range from high to low dB's has been reduced across the entire spectrum. Many of the severe drops/nulls have been tamed. Not sure if you realize this is not a 1/3rd or higher octave graph like most are, this covers 1Hz increments upto 300hz. Many people miss this information from other products used.

Here is another nice article I've found.

http://www.sbrjournal.net/journalsite/archives/acoustics/Acoustics.htm

Don't hold back Chess, tell us what you really think.

I actually read an article on bass traps / acoustic treatments etc just yesterday. I really don't know where I stand on it. Most of them are so damn ugly. I would never get away with placing those things all over the walls.

Chess, you mentioned that you were going to graph the room response. What program do you intend to use? I would like to try something like this as well.

Cheers,

Jordan

Jordan, if you talk to jakeman, royce73, and mrnomas(audioholics writer), all Axiom owners, they will tell you the positive results they received in both their graphs AND a big sound improvement. I frequent other forums where professional musicians and sound engineers hang, I have much faith in their factual statements.

And they don't have to be ugly if you have a little design talent.

>>>Chess, you mentioned that you were going to graph the room response. What program do you intend to use? I would like to try something like this as well.

Jordan you can order a Rives Audio test CD for $21(US) and then download either the color or black and white frequency chart to manually graph the room yourself. You can also download the test tones from RealTraps if you desire.

I have the Rives CD and am using the color frequency charts for manual graphing ... although I've only had the chance to graph a couple of times it's very interesting to view the results after slight room modifications such as doors open/closed, furniture placement and etc.
__________________________________________________________

Good luck with your DIY panel project Randy!

Hey Rick, did you get your Tri-Traps yet from GIK? I thought about building some 4' high superchunks which would be like yours, however, after talking to Ethan Winer and Bryan Pape on the other forums, they talked me into stacking clear to the ceiling.

Jordon, per BrotherBob's suggestions, the options presented are pretty reasonable for a DIY project (manual data logging). I was thinking of doing a complete 20-20 sweep and for that, i would need the Rives ETF software and a laptop.
At this point, i may not have easy access to a laptop and as such, may use the other approach...for now.

I finally go my graphs onto Photobucket - I would love to hear some comments. In my opinion, the treaments made a difference in the room - especially in 2-channel stereo. I also noticed a lot less "echo" and "reverb" when I clapped my hands together. Again, this is all subjective, but maybe the graphs tell a better picture.





I was running my sub a little hot when I made the graph and have since made an adjustment. I used the RIVES AUDIO 2 CD. What do you think?

Royce, can you overlay the two lines on the same graph?
The scale of your graphs is off making it a bit hard to follow changes in the curves.

What software did you use? Or did you manually measure the points with the test tones from the Rives cd?

Incidentally, i came across a website with a listing of a ton of audio software including some of the more common ones that pop up on Google. http://www.audiogrid.com/audio/

I used my Radio Shack meter to make manuall measurements.

I used Excel to make the graph - should not be a problem putting the two together.

Granted the measurements are limited here (and i completely understand why, who wants to measure all 19,999 Hz manually?) but it certainly appears as though some significant changes have occurred in the response.
The line is smoothed and raised from 80-125Hz, the dip around 250 virtually eliminated, and a much smoother, more shallow amplitude response between 315 and 1250. After that the changes are both pluses and minuses offsetting, but certainly would be enough to change the overall sound character of the previous room configuration.

In my enthusiast opinion i would say that the changes bring the line closer to flat than the original configuration.
I would still be curious to see more measurements in between though. I'm planning on doing either a complete 20-20 sweep if i can get software to record the numbers properly, or i may manually measure every 10 myself.
That damn ETF software (demo version) keeps giving me runtime errors. {sigh]

Well i may also have to do some manual measurements unless i can find software that will actually take readings of all frequencies in a sweep and record them in a manner in which i can plot it properly.
I don't want to have to measure 1000 times for that data either, but i will if i have to!!

Just for the record, I have no problem with room treatments. I agree that any given room will have dramatic effects on the sound and that treating the acoustics in the room can improve the sound quality.

Just like anything in life though, there always seem to be trade-offs involved. There seems to be one with regard to aesthetics when treating a room. Currently, I would never get away with strapping absorbers all over our livingroom. When we move to a bigger place I am told by the Minister of Aesthetics (my partner) that I will get my own room to do with what I please. I fully intend to treat this room.

I know that treatments don't all have to be hideously ugly but if you intend to install 8 mini-traps for example I don't know how you could pull that off and make it look good (my subjective opinion).

Cheers,

Jordan

Hey Royce, I have been trying to build a graph in Excel I can use with my realtraps results. You would think an IT guy could figure out Excel. I feel like telling those "Wizzards" where to go.

The first time I used Realtraps CD, I actually printed off the supplied graph and marked the locations on the graph, while my other hand would occasionally have to reach for the SPL meter and change from 70 to 80 to 90 to 70, etc...

I actually found it easier the second time take a piece of paper, on the left side I made a column where I had 20-29hz, 30-39hz, etc... and then I just wrote the decibel readings across the paper, jumped down a line, etc...Then I used Microsoft Paint to actualy enter the dots on their GIF graph.

So, if you figure out how to create a similar graph in Excel, help me out man.

Freakin' nerds.

Randy I haven't received my Tri-Traps yet, I called yesterday and was told by Glen that my order somehow got missed. No biggie, they should be here Monday and the folks were very cool about it.

>>So, if you figure out how to create a similar graph in Excel, help me out man.

I'm going from memory here (misplaced my Office CD in the move) so you might have to interpret the menu items a bit.

I normally enter the FR data (other people's data, I'm too damn lazy to measure my own room) in columns, where the first column is the frequency and the second column is the measured SPL.

Start in the top left hand cell with actual data (eg. your lowest frequency) and select down to SPL for the highest frequency, ie select the data you want to graph.

Insert => Chart, then pick whatever option gets you a new worksheet instead of embedding the chart in the middle of your data table.

I think a little wizard pops up here. It lets you pick what kind of graph style you want. I vaguely remember picking X/Y but that doesn't seem right for an FR graph -- maybe start with a line graph first. You are given all kinds of options for smoothing the lines etc..., stay with "simple".

Other than legends & grid lines, you should be pretty much done at this point.

[EDIT] As long as I'm here, just wanted to say for the record one more time that a single frequency response graph is *not* sufficient to show more than a fraction of the improvements that you can get from good room treatments.

An EQ can fix response at a single point in the room, but you need room treatments (bass traps) and/or speaker relocation to get decent response across a listening area of more than one seat. You would need to measure response at a number of locations and plot them all (before and after) to show this improvement.

Similarly, many of the improvements from room treatment simply won't show on an FR graph at all. Reductions in echo need a more complex graph (spectral decay ?) to see the change. For changes like getting the right level of diffusion (which can open up the sound of a room in a similar way as going from direct surrounds to QS surrounds) I have no idea *how* to measure the results in a graph.

Regarding appearance, it's worth taking a spin through some of the sample rooms on the Rives Audio site to see what you can do. While I prefer the look of rooms with dramatic and highly visible treatments (as, I suspect, do most guys ) they actually design most of their rooms with hidden treatments right down to embedding large Helmholz resonators in custom-built furniture. It's really worth a visit to see what can be hidden in walls and ceilings.

For practical budgets, this translates into "don't hang ugly stuff on the drywall, use the space between the studs".

Thanks John, that was all the help I needed. I am now transferring my data from the manual method to this new spreadsheet. Then I can try to figure out how to add another line with a different color for stats with the bass traps in place for comparison purposes.

We quiver with antici....... pation.

Glad to hear that, G-Man.

Well everyone, I got both of my 8ft superchunk bass traps finished tonight on the rear wall. Took a few pictures, hope to post them soon. I put my Fleetwood Mac Rumors CD in and I swear the bass does sound tighter, better, killer, awesome, etc... I plan to do a graph with these added and then another graph once I get my 1st reflection points done. I also plan to do something in the rear corners for broadband bass trapping as well. Since I have to make the wife happy, I'm planning on some creative ways to include bass traps and keep her happy.

Congratulations on getting the traps finished. Looking forward to the pics.

I wouldn't bother doing another graph after treating the first reflection points -- while the treatments are likely to make a difference, it's not a difference which will really show up on an FR graph.

There is no substitute for a group of acoustically insignificant assistants (aka kids) running in and out with the treatments while your eyes are closed.

If you look at Royce's before/after combined graph a few posts ago, he actually saw some decent improvement with just 4 4" straddled bass traps in the corners and only 2 side first reflection points. Also, his graph is not plotted in 1hz increments like the Real Traps CD, so many peaks and dips won't even show up and will be missed.

graphs graphs and more graphs, that is the question.