[rcag_ils]

I finally get to fire up my system after moving it to the other side of the room, the result is disappointing.

The sound turned out to be very shallow, and shrilling, I suspect I am encountering reflection problem from the bare wall.

If some of you have some type of room treatment in place, and care to give me some advice, it'd be great.

I can't place anymore furniture in the room for one, my requirement is, whatever that I need to put on the wall would have to be:

A. low cost, less than $40.00, $50.00 at the most.
B. looks good. Will easily integrate with the rest of the decor in the room.
C. easy to make.
D. light weight, easy to put on and take off, after taken off, it won't leave any trace on the wall that would require touch-up work,  would not affect the resale of the house.
E. Will improve the sound for sure.

Are such things exist?

 

[turkey]

You can often get a wool throw rug inexpensively and hang it on the wall. I just checked and there are some nice-looking ones on Ebay.

A blanket with a nice pattern might be another good bet.

[Zheeeem]

Such things exist.

But, of course, without actually knowing what is causing your problem it's hard to know if the treatment you're after will work.

Room treatments are generally a good thing.  Sidewall reflections can be a very significant problem.  What you might consider is temporarily putting a random collection of pillows, laundry and other absorbers at the reflection point.  If this makes the difference, then do something slightly more elegant - either an oriental rug or similar decorative fabric that can be hung on the wall (with an inch or two of cotton upholstery batting behind it) or some OC 703 or equivalent 2" fiberboard, cut to size and covered with fabric.  Bear in mind that absorbers do not absorb uniformly across all audible frequencies, and until you get into thicker materials (e.g. 4 inches or more) there is limited bass absorption.

[turkey]

Room treatments are generally a good thing.  

But not always.

There is some good info in this whitepaper: http://www.gedlee.com/downloads/Cum%20laude.pdf

My next step is to buy a copy of Dr Geddes' book on Home Theater.

[bpape]

Just understand that he's looking at things purely from a frequency response standpoint and suggesting multiple bass sources to minimize modal activity.  While this can work very well in the frequency domain, it does absolutely nothing to address the time domain.  In small rooms, decay times from 100Hz down (assuming no treatment and even with multiple sources) can be well over 1 second.  This can result in masking of low level detail and muddying of the bass instead of a nice, tight, extended, nimble bottom end.

Also, to say treatment is not always a good thing isn't quite accurate.  There are many many different types of treatment other than simple absorption.

Bryan

[rcag_ils]

As far as hanging rug on the back wall, I've already have some real nice framed pictures in place, so it's not an option for now.

The right side is the walkout door, when the blinds are closed, it has a kind of a rough texture on it, so I don't think it would reflect the sound.

The upper left side wall is bare, lower part of the wall are my Lps rack, so they won't reflect sound.

Treating the ceiling would be too big of a project for me to take on, so it's not an option.

I think I'll start with the left upper wall, and see how it'll work out.

[turkey]

Just understand that he's looking at things purely from a frequency response standpoint and suggesting multiple bass sources to minimize modal activity.  While this can work very well in the frequency domain, it does absolutely nothing to address the time domain.  In small rooms, decay times from 100Hz down (assuming no treatment and even with multiple sources) can be well over 1 second.  This can result in masking of low level detail and muddying of the bass instead of a nice, tight, extended, nimble bottom end.

What kind of treatment for a home listening room would you recommend that would be effective at the lowest frequencies, yet not over-dampen at higher frequencies?

Also, to say treatment is not always a good thing isn't quite accurate.  There are many many different types of treatment other than simple absorption.

I stand by my statement. I have heard some horrible results in studios when someone figured that, "the more treatment, the better."

I don't feel that the converse of my statement is true. (The converse would obviously be "room treatment is always a good thing.")

[bpape]

My point exactly.  You previously said that room treatment isn't always a good thing.  Too much and/or too much of the wrong thing can absolutely be a bad idea.  Never said the more the better.  I just said that saying that sometimes treatment in a room isn't a good idea is not correct.

There are several types of absorbers that can be done using membranes that will have from 50% to 0 upper mid and high frequency absorption  and still be effective in the bass.  As you get more toward 0, the narrower in range they get and you need several different sizes to cover the bass spectrum properly.  These usually have wood as the membrane and are effective over about a 2 octave range.  Those usually are also less efficient per unit area than broader range absorbers with thinner membranes.  So, in a smaller room, where you don't have a lot of space to begin with, each treatment should naturally do more or you'll end up with half your wall surface in wood membranes.

In reality, it's generally a mix of a few, carefully places upper mid and high absorbers along with some broadband bass control with reduced high frequency absorption that provides the best results depending on the room and the usage. 

You can also use diffusion at reflection points instead of absorption and combine it with broadband bass control if you prefer that and assuming you have enough distance to make the diffusion effective.  Combine this method of bringing decay time and ringing down and multiple bass sources, and you've pretty well got the bass under control.

Bryan

[honesthoff]

I had a similar problem, and fixed most of it by replacing my many glass-covered framed prints on my back and front walls with GIK 244 bass traps.  They are a couple of dollars more than your limit, but not by much, and they are easy to take down and put up.  They hang just like a picture with hooks and hanging wire.

[youngho]

Just understand that he's looking at things purely from a frequency response standpoint and suggesting multiple bass sources to minimize modal activity.  While this can work very well in the frequency domain, it does absolutely nothing to address the time domain.  In small rooms, decay times from 100Hz down (assuming no treatment and even with multiple sources) can be well over 1 second.  This can result in masking of low level detail and muddying of the bass instead of a nice, tight, extended, nimble bottom end.

The second sentence is incorrect in that addressing the frequency domain will usually address the time domain below 80 Hz. See pages 20-23 here (http://www.diyaudio.com/forums/showthread.php?s=&threadid=134568&perpage=25&pagenumber=20). This is also discussed in Floyd Toole's book.

[bpape]

Sorry but that's incorrect.  Addressing issues in the frequency domain may help by minimizing the extended tails of modal issues - but it doesn't change the overall decay time of the entire spectrum. 

Bryan

[youngho]

Sorry but that's incorrect.  Addressing issues in the frequency domain may help by minimizing the extended tails of modal issues - but it doesn't change the overall decay time of the entire spectrum. 

Don't take my word for it. A few plots of real measurements from real rooms are included in the links and also Toole's book. Decay time is addressed. Again, I'm talking specifically about lower than 80 Hz, not the entire spectrum. Could you please post some waterfall plots backing up what you're saying?

[bpape]

How do I post a plot of a multi-bass source with no treatments that has proper decay time across the spectrum?  I can't.  As I said - if you can minimize the modal issues - you'll also minimize their excessive ringing OF THOSE MODAL FREQUENCIES - to be no worse than the rest of the bass spectrum - which is still too long in almost all untreated smaller rooms (not auditoriums, etc. where large room acoustics apply).  All it can do is make it more even across the board, not necessarily correct.  Yes - this is an improvement - but not a complete solution. 

Let me turn the tables... Please post a waterfall of a room that has proper decay time across the spectrum with no treatments and no EQ purely due to muti-location bass sources to prove that it does work.    Just saying you're only speaking about 80Hz down doesn't mean anything.  Even if it did work (which it won't), if you still have massive ringing from 80-300Hz, you still have an issue that requires treatment.  The point at which you shift from modal to non-modal activity is completely dependent on the dimensions of the room. 

Frank,

I apologize for this thread taking off this way in your circle.  I just couldn't let the comment that there are times where it's bad to use any sort of treatment.  I'd be happy to continue this discussion in a more appropriate place.

Bryan

[youngho]

We're basically arguing at cross-purposes.

multiple bass sources to minimize modal activity...does absolutely nothing to address the time domain.

Your words. Wrong.

As I said - if you can minimize the modal issues - you'll also minimize their excessive ringing OF THOSE MODAL FREQUENCIES

Your words. Right. After all, ringing is in the time domain.

No one argued that "it's bad to use any sort of treatment" (your words). That would be stupid. That was a straw man argument that you misinterpreted from turkey's badly written statement, where he replied "Not always" to "Room treatments are generally a good thing." When might room treatments be undesirable? Sigfried Linkwitz writes "Room treatment can be very effective above 200 Hz, but the same result may be obtained more aesthetically with ordinary furnishings, wall decoration, rugs on the floor and the variety of stuff we like to surround ourselves with" and "Rather than special products for acoustic treatment of a room I prefer the normal stuff of life - books, curtains, pictures, rugs, wall hangings, shelves, cabinets, chairs, sofas, etc. - to establish the acoustics of my living spaces." In his book, Floyd Toole seems to feel similarly for casual listening rooms, but he does suggest significant room treatments for dedicated listening spaces.

By the way, Geddes advocates for LF absorption. Make no mistake about it, since you seem to think that "he's looking at things purely from a frequency response standpoint and suggesting multiple bass sources to minimize modal activity" (your words). In fact, he argues strongly for "good LF absorption" in his book and in post 24 from the DIYaudio thread.

I'm done talking about this, so I will not write any more in this thread, either.

[sueata1]

As Frank has said many times in past Audio Basics,,,"you don't want a Good sounding room,,,,,you want your room to Not Sound at all".
The best place to start is the wall behind the speakers,,,take those pics down and hang a few Thick nice looking rugs,,,(available very reasonable at any Flea Mkts.).  Once you get all room reflections Tamed your Image will be locked in and Not smeared...You will not believe how good your system can sound when playing in a DEAD room ...

Happy listening,,,
Mel

[turkey]

As Frank has said many times in past Audio Basics,,,"you don't want a Good sounding room,,,,,you want your room to Not Sound at all".
The best place to start is the wall behind the speakers,,,take those pics down and hang a few Thick nice looking rugs,,,(available very reasonable at any Flea Mkts.).  Once you get all room reflections Tamed your Image will be locked in and Not smeared...You will not believe how good your system can sound when playing in a DEAD room ...

Many people have found that they don't like the sound of a very dead room at all.

A very live room is bad, but so is a very dead one.

[BrianM]

As Frank has said many times in past Audio Basics,,,"you don't want a Good sounding room,,,,,you want your room to Not Sound at all".
The best place to start is the wall behind the speakers,,,take those pics down and hang a few Thick nice looking rugs,,,(available very reasonable at any Flea Mkts.).  Once you get all room reflections Tamed your Image will be locked in and Not smeared...You will not believe how good your system can sound when playing in a DEAD room ...

Many people have found that they don't like the sound of a very dead room at all.

A very live room is bad, but so is a very dead one.

I think it depends on the gear (especially the speakers) and the distance from reflection points to the listener.  In smaller rooms you want to err on the side of dead, in my experience, though I suppose anything can be overdone.  I like to do the hand clap test; should be no reverb but the topmost frequency of the clap should still sound audible and present.  I listen in a small room and have rugs hanging on all 4 walls.  It's relatively dead, but the sound ain't.  You do need gear and speakers that perform pretty flat all the way up, of course.

[rcag_ils]

Hanging rugs would have been a good idea, I am sure there are some nice looking one out there, but I don't really have a whole lot of control on the looks of the rugs.

I prefer some DIY plan that would allow me to build the sound taming panels with the material available at the local hardware store.

I know there are some that I can purchase, but they are generally at $60.00 for a 12" X 12" size. And the more professional looking one would make my room looks like a laboratory, they are also very expensive, not good.

[turkey]

I prefer some DIY plan that would allow me to build the sound taming panels with the material available at the local hardware store.

I know there are some that I can purchase, but they are generally at $60.00 for a 12" X 12" size. And the more professional looking one would make my room looks like a laboratory, they are also very expensive, not good.

I once took some Sonex foam tiles I scavenged from a studio that was being remodeled, glued them to a piece of fiberboard, and then covered the front with a sheet of thin cloth (I think what I used was rayon). Then I just leaned them up against the side walls.

The Sonex tiles were pretty scruffy-looking and had very low SAF. Once covered with the cloth they were innocuous enough to pass muster in the living room.

They seemed to work ok too.