BlueWizard
Distinguished Member
In a recent thread titled - "Primer: How much do I have to spend to get a good Stereo?", the subject tuned to Room Acoustic as an aspect of properly implementing a Stereo or Surround Sound system into a room.
http://www.avforums.com/forums/hi-f...how-much-do-i-have-spend-get-good-stereo.html
While I am aware that there is a Room Acoustic Forum at AVForums, I think it is worth discussing here as an extension of your audio system, and as general knowledge to be considered when one places a stereo in a room, or considers what equipment is suitable in a given room.
In that context, I think a discussion of acoustic as an extension of my previous threat, and as an extension of an audio system is a topic worth discussing in the HiFi Systems forum.
Room Acoustics, Audio and Video Calibration | AVForums.com - UK Online
First an overview -
There is a trend in the UK toward ultra-modern ultra-minimalistic rooms, and even I will admit these are attractive, but they are an acoustical nightmare; very reflective with little or no sound absorbing surfaces.
On the other hand, your grandmother probably lives in a very clutter, softly furnished room with curtains, rugs, carpets, and wide collection of odd furniture. This is very probably an acoustically good room. It has both absorption, absorbing of sound, and diffusion, the rebounding of sound in diverse directions.
For general consumer audio equipment, room acoustics only need be given general consideration. However, the more expensive, and more precise and revealing your equipment becomes, the more small things make a big difference. In this situation, you want to give serious consideration to the room acoustics. Bad or poor room acoustics can ruin the sound from an otherwise great sounding system.
So, what do we consider? Reflection is the first killer of sound systems.
How do we deal with it? In one of or a combination of two ways -
Absorption - Absorbing sound in the room to prevent it from being reflected back and interfering with the on-coming main sound from the speakers.
Diffusion - A room must have a bit of echo to it, otherwise it sounds dead and lifeless. So, rather than absorb all the sound, we scatter it in diverse directions.
There are also products that deal with both Absorption and Diffusion to varying degrees.
On the nature of Reflection -
There are two primary aspects to Reflection.
One is at mid and high frequencies. This produces a noticeable echo or reverberation in the room. We want a trace of this to give some life to the music, but too much causes problems.
Next is low frequency reflection; when a wall or wave of low frequency sound comes out of the speaker, travels across the room, and rebounds off the back wall, the rebound then moves toward the front of the room colliding with on-coming sound waves. Depending on the timing of the intersecting waves, they can re-enforce each other, or they can interfere or cancel each other out.
This will either cause areas of intense bass, or areas in the room of almost no base, and these areas can be at best feet and sometimes inches apart. Sometimes just moving our head to the side is enough to move out of a Null and into a Peak.
Absorption can be as simple as acoustic tile on the ceiling. Though most don't realize it, the panels that make up office cubicles are sound absorbing panels, which is why most office spaces have very dead acoustics.
Though, in recording studios or nice home theaters or music rooms, one might use Acoustical Foam Panels like this -
Here is an example of Pyramid foam that both absorbs and diffuses -
4 Inch Studiofoam Pyramids - Acoustic foam sound absorption products from Auralex Acoustics.
Here us an example of Wedge foam -
3 Inch Studiofoam Wedges - Acoustic foam sound absorption products from Auralex Acoustics.
Here is an example of foam in various depth strips that again acts as both absorption and diffusion -
2 Inch Studifoam Metro - Acoustic foam sound absorption products from Auralex Acoustics.
As well as foam there are fabric covered panels -
SonoSuede™ Systems - CLASS A - Acoustic sound absorption products from Auralex Acoustics.
And if you are rolling in dough, there are decorative Sound Absorbing Panels -
SonicPrint by Auralex
The depth of the foam or the depth of the fabric panels determine the depth of frequency that will be absorbed by the panel.
Diffusion breaks up on-coming waves into smaller waves that are diffused or scattered in all directions. This will become evident when you see some of the various Diffusion Panels.
Here is an example of a Home Cinema room that uses a combination of a variety of Diffusion panels plus sound absorbing panels -
Acoustics 101 | Home Theater
This is also an article on the basics of Room Acoustics.
Diffusion panels come in a variety of forms, they can be larger or small wedges, the can be waves, boxes, triangles, pyramids, posts, and many other forms.
You can see a variety of them here -
Auralex Acoustics - Sustain Bamboo Diffusors
In the photos above you see large wooden wedges, but smaller wedges are also possible as seen in the video below -
It is also possible to find software on the Internet to help you make your own box or post Diffusers, as the video below shows -
Believe it or not, a simple bookshelf filled with books makes a good Diffuser.
Here is another example of a room with Diffusion. Notice the curve wood panels on the walls and ceiling. These panels will scatter any sound that hits them -
Panama Escape | Home Theater
Though it is not as obvious, this room is probably using a fair amount of absorption as well.
Here is a website that specializes in Wave Diffusers -
WAV-001 Sound Diffusion Panel | Sound Diffusion TechnologySound Diffusion Technology
Again, these would be easy enough to make on your own with some simply PVC plumbing pipe. Since the tubes or waves are round, any sound striking them will be reflect off in a infinite variety of angles. The Wave Tubes could be place on top of some acoustical foam for both diffusion and absorption.
Just as you can make your own diffusion products with a little bit of imagination and some ingenuity, you can also make your own Absorption Panels or Bass Traps. The difference between an Absorption Panel and a Bass Trap is the depth of the panel. The deeper the panel, the deeper the frequency it will absorb.
There are countless videos on YouTube about making your own sound absorbing panels. Some are crude an very inexpensive and use products commonly available to everyone. And some can be more precise and expensive, occasionally requiring a special order of some materials.
If you use ridged Fiberglas insulation or Rockwool, then it is possible to make Frameless panels. With softer fluffy fiberglas house insulation, you will probably need to make a simple wood frame for the panels.
Here is an example -
I've found that Stretch Double Knit fabric from the fabric store works well. It is cheap, strong, and acoustically transparent. You can also use more expensive grill cloth or similar.
OK, so fine, you say, but how do I know what to do, and what do I do?
To start with, you simply look around your room. If you see a lot of bare open flat surfaces, then you need to cover them with something. Put a rug on the floor between the sofa and the music system. Put pictures or better yet, hang a tapestry on the wall. If necessary, you can build your own sound panels as shown in the video.
Even a large plant in the corner can make a difference. A bookshelf can soften the acoustics in a room. Some type of decorative diffusion on the wall opposite the speakers.
In many of the links, by the standards of a common person with a common income, they have gone a bit overboard, but for the average person, you need not go that far. But if you have a big bare empty room, you have to do something to tame the echo and reflections.
Perhaps the Significant Other (wife, girlfriend, boyfriend,...) doesn't like the ideas of bland bare panels hanging on the walls. Well, perhaps you could make a shelf on the lower part of the panel, and your Sig.Other could place objet d'art on them. Any nick-knacks or similar objects place on the panel's shelf simply act as diffusers. Plus, you can always claim that the panel will make the objet d'art stand out.
And remember, the panels don't have to be a solid color. You can find many patterned/printed fabrics at the fabric store that might blend in better. To test any given fabric for acoustical transparency, simply hold it up to the light, the better you can see through it, the better sound will travel though the fabric and be absorbed by the material inside.
Here is an example, of the difference Acoustic Panels can make. Later on in this video, you see a hand-clap test in a large Church before and after the acoustic panels have been installed.
It really gets down to person ingenuity. Every problem has a solution, if you are willing to seek it out.
Acoustic treatments, might take some effort, but they need not be expensive. In some cases, it is simply a matter of how what you have can best serve the acoustics of the room.
That should get the conversation started.
Steve/bluewizard
http://www.avforums.com/forums/hi-f...how-much-do-i-have-spend-get-good-stereo.html
While I am aware that there is a Room Acoustic Forum at AVForums, I think it is worth discussing here as an extension of your audio system, and as general knowledge to be considered when one places a stereo in a room, or considers what equipment is suitable in a given room.
In that context, I think a discussion of acoustic as an extension of my previous threat, and as an extension of an audio system is a topic worth discussing in the HiFi Systems forum.
Room Acoustics, Audio and Video Calibration | AVForums.com - UK Online
First an overview -
There is a trend in the UK toward ultra-modern ultra-minimalistic rooms, and even I will admit these are attractive, but they are an acoustical nightmare; very reflective with little or no sound absorbing surfaces.
On the other hand, your grandmother probably lives in a very clutter, softly furnished room with curtains, rugs, carpets, and wide collection of odd furniture. This is very probably an acoustically good room. It has both absorption, absorbing of sound, and diffusion, the rebounding of sound in diverse directions.
For general consumer audio equipment, room acoustics only need be given general consideration. However, the more expensive, and more precise and revealing your equipment becomes, the more small things make a big difference. In this situation, you want to give serious consideration to the room acoustics. Bad or poor room acoustics can ruin the sound from an otherwise great sounding system.
So, what do we consider? Reflection is the first killer of sound systems.
How do we deal with it? In one of or a combination of two ways -
Absorption - Absorbing sound in the room to prevent it from being reflected back and interfering with the on-coming main sound from the speakers.
Diffusion - A room must have a bit of echo to it, otherwise it sounds dead and lifeless. So, rather than absorb all the sound, we scatter it in diverse directions.
There are also products that deal with both Absorption and Diffusion to varying degrees.
On the nature of Reflection -
There are two primary aspects to Reflection.
One is at mid and high frequencies. This produces a noticeable echo or reverberation in the room. We want a trace of this to give some life to the music, but too much causes problems.
Next is low frequency reflection; when a wall or wave of low frequency sound comes out of the speaker, travels across the room, and rebounds off the back wall, the rebound then moves toward the front of the room colliding with on-coming sound waves. Depending on the timing of the intersecting waves, they can re-enforce each other, or they can interfere or cancel each other out.
This will either cause areas of intense bass, or areas in the room of almost no base, and these areas can be at best feet and sometimes inches apart. Sometimes just moving our head to the side is enough to move out of a Null and into a Peak.
Absorption can be as simple as acoustic tile on the ceiling. Though most don't realize it, the panels that make up office cubicles are sound absorbing panels, which is why most office spaces have very dead acoustics.
Though, in recording studios or nice home theaters or music rooms, one might use Acoustical Foam Panels like this -
Here is an example of Pyramid foam that both absorbs and diffuses -
4 Inch Studiofoam Pyramids - Acoustic foam sound absorption products from Auralex Acoustics.
Here us an example of Wedge foam -
3 Inch Studiofoam Wedges - Acoustic foam sound absorption products from Auralex Acoustics.
Here is an example of foam in various depth strips that again acts as both absorption and diffusion -
2 Inch Studifoam Metro - Acoustic foam sound absorption products from Auralex Acoustics.
As well as foam there are fabric covered panels -
SonoSuede™ Systems - CLASS A - Acoustic sound absorption products from Auralex Acoustics.
And if you are rolling in dough, there are decorative Sound Absorbing Panels -
SonicPrint by Auralex
The depth of the foam or the depth of the fabric panels determine the depth of frequency that will be absorbed by the panel.
Diffusion breaks up on-coming waves into smaller waves that are diffused or scattered in all directions. This will become evident when you see some of the various Diffusion Panels.
Here is an example of a Home Cinema room that uses a combination of a variety of Diffusion panels plus sound absorbing panels -
Acoustics 101 | Home Theater
This is also an article on the basics of Room Acoustics.
Diffusion panels come in a variety of forms, they can be larger or small wedges, the can be waves, boxes, triangles, pyramids, posts, and many other forms.
You can see a variety of them here -
Auralex Acoustics - Sustain Bamboo Diffusors
In the photos above you see large wooden wedges, but smaller wedges are also possible as seen in the video below -
It is also possible to find software on the Internet to help you make your own box or post Diffusers, as the video below shows -
Believe it or not, a simple bookshelf filled with books makes a good Diffuser.
Here is another example of a room with Diffusion. Notice the curve wood panels on the walls and ceiling. These panels will scatter any sound that hits them -
Panama Escape | Home Theater
Though it is not as obvious, this room is probably using a fair amount of absorption as well.
Here is a website that specializes in Wave Diffusers -
WAV-001 Sound Diffusion Panel | Sound Diffusion TechnologySound Diffusion Technology
Again, these would be easy enough to make on your own with some simply PVC plumbing pipe. Since the tubes or waves are round, any sound striking them will be reflect off in a infinite variety of angles. The Wave Tubes could be place on top of some acoustical foam for both diffusion and absorption.
Just as you can make your own diffusion products with a little bit of imagination and some ingenuity, you can also make your own Absorption Panels or Bass Traps. The difference between an Absorption Panel and a Bass Trap is the depth of the panel. The deeper the panel, the deeper the frequency it will absorb.
There are countless videos on YouTube about making your own sound absorbing panels. Some are crude an very inexpensive and use products commonly available to everyone. And some can be more precise and expensive, occasionally requiring a special order of some materials.
If you use ridged Fiberglas insulation or Rockwool, then it is possible to make Frameless panels. With softer fluffy fiberglas house insulation, you will probably need to make a simple wood frame for the panels.
Here is an example -
I've found that Stretch Double Knit fabric from the fabric store works well. It is cheap, strong, and acoustically transparent. You can also use more expensive grill cloth or similar.
OK, so fine, you say, but how do I know what to do, and what do I do?
To start with, you simply look around your room. If you see a lot of bare open flat surfaces, then you need to cover them with something. Put a rug on the floor between the sofa and the music system. Put pictures or better yet, hang a tapestry on the wall. If necessary, you can build your own sound panels as shown in the video.
Even a large plant in the corner can make a difference. A bookshelf can soften the acoustics in a room. Some type of decorative diffusion on the wall opposite the speakers.
In many of the links, by the standards of a common person with a common income, they have gone a bit overboard, but for the average person, you need not go that far. But if you have a big bare empty room, you have to do something to tame the echo and reflections.
Perhaps the Significant Other (wife, girlfriend, boyfriend,...) doesn't like the ideas of bland bare panels hanging on the walls. Well, perhaps you could make a shelf on the lower part of the panel, and your Sig.Other could place objet d'art on them. Any nick-knacks or similar objects place on the panel's shelf simply act as diffusers. Plus, you can always claim that the panel will make the objet d'art stand out.
And remember, the panels don't have to be a solid color. You can find many patterned/printed fabrics at the fabric store that might blend in better. To test any given fabric for acoustical transparency, simply hold it up to the light, the better you can see through it, the better sound will travel though the fabric and be absorbed by the material inside.
Here is an example, of the difference Acoustic Panels can make. Later on in this video, you see a hand-clap test in a large Church before and after the acoustic panels have been installed.
It really gets down to person ingenuity. Every problem has a solution, if you are willing to seek it out.
Acoustic treatments, might take some effort, but they need not be expensive. In some cases, it is simply a matter of how what you have can best serve the acoustics of the room.
That should get the conversation started.
Steve/bluewizard
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