[JLM]

Guy:

I like your room size and shape.  Sound transmission in and out should be good (pending on quality of windows which in a warm 3rd world climate I'd expect to be poor).

Yes, reinforced concrete is probably the right term if ribbed steel rods were used.   (There is also pre-stressed and post-tensioned types that use highly tensioned high strength wire to more efficiently increase flexural capacity.  Do not cut one of those wires!)  Note that I have a degree in civil engineering, am a licensed professional engineer, worked for 8 years as a structural engineer, and am a past member of the American Concrete Institute. 

Are the wall plastered or drywalled?  (If so, that is the material you're 'hearing'.)

What is your problem with the sound of the room?  What problem are you trying to solve?  Is it the room or the speakers?  Is it your expectations?  You haven't stated a specific compliant.

How do you know that you have a problem?  Have you measured the frequency response with test tones (free downloads) and a microphone (cheap/could borrow)? 

Have you tried near field setup (moving speakers farther into the room)?  It's free.  The only image I see of your speakers show them to be quite 'packed' into the corners, which should be expected to produce bass boom.

The only image I see of your speakers are equal distance from front/side walls (not recommended).  Try 60 cm from side walls and 100 cm from front wall.

Again, forget the styrofoam or curtains, they're useless.  I'll give you six 2 ft x 4 ft GIK 244 panels (covered in off white fabric), just pay for packaging and shipping from 48867.

Until you define the problem and try moving the speakers out of the corners, I can't take this thread seriously.

[Guy 13]

Hi JLM and all Audio Circle members.

I like your room size and shape.  Sound transmission in and out should be good (pending on quality of windows which in a warm 3rd world climate I'd expect to be poor).

I also like my room, mainly because it’s MY room, not my WIFE’S  living room.
The window near the desk is high quality imported window, the same goes for the door.
However, the (More important) window, the one behind the speakers is a Made in Vietnam triple cheap rustable iron window,
But it does not rattle with lots of bass.

Yes, reinforced concrete is probably the right term if ribbed steel rods were used.
The beams, the floor and ceiling are all reinforced concrete.

(There is also pre-stressed and post-tensioned types that use highly tensioned high strength wire to more efficiently increase flexural capacity.  Do not cut one of those wires!)  Note that I have a degree in civil engineering, am a licensed professional engineer, worked for 8 years as a structural engineer, and am a past member of the American Concrete Institute. 

No pre-stressed and post-tensioned concrete in our house.
I am no expert in house structure, but I would never cut anything in the structure itself.
Wow, you should know what you are talking about, that’s good,
too many people pretend to be experts, but they are not…

Are the wall plastered or drywalled?  (If so, that is the material you're 'hearing'.)
All the walls are made of one layer of red bricks
and covered with a ½” layer of cement,
then another thin layer of plaster to give the wall a smooth finish.

What is your problem with the sound of the room?  What problem are you trying to solve?  Is it the room or the speakers?  Is it your expectations?  You haven't stated a specific compliant.
My complaint is mainly the bass that at certain frequencies disappear and at other frequencies it’s booming.
The mids and highs seem to be O.K., cannot really complain.

How do you know that you have a problem?  Have you measured the frequency response with test tones (free downloads) and a microphone (cheap/could borrow)?
I know I have a problem, because I can hear it.
I’ve used a Chesky test frequencies CD and just by ear it’s obvious,
no need a microphone for now.

Have you tried near field setup (moving speakers farther into the room)? 
It's free.
Yes, I’ve tried that, now how close?
I don’t want to be too close, I just don’t like it that way.

 The only image I see of your speakers show them to be quite 'packed' into the corners, which should be expected to produce bass boom.
Prior to take the pictures, I’ve installed under carpet cushion, that’s why the speakers had to be pushed in the corner.
Normally the speakers are 2 feet from the side walls and 5 feet from the back wall.

The only image I see of your speakers are equal distance from front/side walls (not recommended).  Try 60 cm from side walls and 100 cm from front wall.
As soon as I finish some cleaning, they will go back to their ideal placement.

Again, forget the styrofoam or curtains, they're useless.  I'll give you six 2 ft x 4 ft GIK 244 panels (covered in off white fabric), just pay for packaging and shipping from 48867.
WOW ! That’s a nice offer, I am touched.
How can I refuse such a nice offer?
What city is: 48867?
Ruben from Fallen Enclosures might help me to consolidate some stuff I bough, I could arrange to get your gift sent to him.
I will get back to you on your generous offer.
Thanks a lot, the poor audiophile that I am thanks you again and again.

Until you define the problem and try moving the speakers out of the corners, I can't take this thread seriously.
Now, are you taking this post seriously?
Also have a look at the pictures I sent to MarvinTheMagician.

Guy 13
AKA:
The grateful audiophile in Vietnam,
not from Vietnam.

[JLM]

Yes, the biggest advantage to having a dedicated room is that you can listen to what, when, and how loud you want.  IMO the biggest mistake most audiophiles make is to overspend on gear compared to the listening environment they're using.

Plaster is harder (more reflective) than drywall (most popular wall construction in the U.S.).  But the overall wall construction should be very rigid and so not contributing via resonance (flexure).  My gues is that you're suffering from what Floyd Toole describes in his book "Sound Reproduction."  His analogy used a bath tub filled with 10 cm of water and using a hand to push water from one end to the other (like your speakers are doing now as they're both at one end of the room).  The waves slosh back and forth, from end to end.  As they move back and forth the waves 'interfere' with each other, sometimes cancelling each other, sometimes doubling each other.  Bass waves in your room can do the same (different places in the room at different frequencies).  This cancelling/doubling can cause a +/- 20 dB response.

The answer is not in treatments or EQ but to use a 'swarm' of subwoofers, spread around the room.  (Search audiocircle or google for 'swarm'.)  Minimum two subwoofers at opposite ends of the room, but three or four is recommended.  Another option is found here:  http://www.spatialcomputer.com/page9/page10/page10.html

Nearfield is a loosely defined term.  I use a 70 inch equilaterial triangle (speakers/listening position) as per Cardas (but some go much smaller, that could fit on a desktop) that images halfway between headphones/farfield.  The soundstage 'snaps' into place, even 8 year olds are wow'd by the effect.

Unless you're well trained in acoustics, don't kid yourself about what frequencies/dB you're hearing, do yourself a favor and do the testing.  (Most audiophiles under estimate sound pressure levels and miss judge the frequencies they're hearing, especially bass.)

Zip code 48867 is Owosso, Michigan.  Let me know where they'd be shipped to and I can look into the cost.

[Guy 13]

Yes, the biggest advantage to having a dedicated room is that you can listen to what, when, and how loud you want.  IMO the biggest mistake most audiophiles make is to overspend on gear compared to the listening environment they're using.

  I don't know how to comment your post and/or insert my comments, therefore I will use the little smiley at the beginning of each sentence each time I will comment.
My listening room is right above our bedroom and believe it or not I can ply music full blast and my wife don't hear a thing. That's the advantage of 10" of reinforced concrete.

Plaster is harder (more reflective) than drywall (most popular wall construction in the U.S.).  But the overall wall construction should be very rigid and so not contributing via resonance (flexure).  My guest is that you're suffering from what Floyd Toole describes in his book "Sound Reproduction."  His analogy used a bath tub filled with 10 cm of water and using a hand to push water from one end to the other (like your speakers are doing now as they're both at one end of the room).  The waves slosh back and forth, from end to end.  As they move back and forth the waves 'interfere' with each other, sometimes cancelling each other, sometimes doubling each other.  Bass waves in your room can do the same (different places in the room at different frequencies).  This cancelling/doubling can cause a +/- 20 dB response.
  I agree with you.

The answer is not in treatments or EQ but to use a 'swarm' of subwoofers, spread around the room.  (Search audiocircle or google for 'swarm'.)  Minimum two subwoofers at opposite ends of the room, but three or four is recommended.  Another option is found here:  http://www.spatialcomputer.com/page9/page10/page10.html
  I have two Rythmik F12G sealed servo subwoofers that only wait to be connected to my amplifier.

Nearfield is a loosely defined term.  I use a 70 inch equilaterial triangle (speakers/listening position) as per Cardas (but some go much smaller, that could fit on a desktop) that images halfway between headphones/farfield.  The soundstage 'snaps' into place, even 8 year olds are wow'd by the effect.
  70" that's close, very close...

Unless you're well trained in acoustics, don't kid yourself about what frequencies/dB you're hearing, do yourself a favor and do the testing.  (Most audiophiles under estimate sound pressure levels and miss judge the frequencies they're hearing, especially bass.)
  I am looking at something that is simple and inexpensive to make
some db/frequencies measurements.

Zip code 48867 is Owosso, Michigan.  Let me know where they'd be shipped to and I can look into the cost.
  Put those GIK 244 bass trap aside and don't let anyone touch them, now they are mine.
I will get back to you as soon as possible.
Hope you wont charge me stocking fees.

Thanks again for everything.

Guy 13

[Hipper]

REW is a measuring software that is free. You need a computer, microphone (Behringer ECM8000 is relatively cheap and effective - in Europe anyway), microphone stand and cable. Some use a sound pressure level meter instead of a microphone.

However, REW is not simple, nor I suspect is any other decent measuring software, because it's a complicated subject.

The simplest way would be to buy a test CD with test tones (Stereophile's first one is good) and a sound pressure level meter like the ubiquitous Radio Shack one.

Both these approaches will help you position your speakers and ears for least problematic sound and will identify the areas you can improve with room treatment. If you use an equaliser as I do it can show you what settings you need.

I've been a wannabee audiophile for around nine years but it's taken me to this year to get things approaching right. I'd dabbled with test tones and SPL meters but this year I decided to do the job properly and use REW. It's tough to learn as there are so many things to go wrong and so many options, but there's good advice on their forum. I wouldn't say it was 100% accurate (I can't believe any software/microphone combination is) but it will get you near your target. The final test is always your ears.

If you plan on listening seriously for a number of years, changing rooms, houses and equipment, I recommend learning a software like REW now as it will help you well in the future.

[Ethan Winer]

REW is not simple, nor I suspect is any other decent measuring software, because it's a complicated subject.

Agreed, using REW is more complicated than playing test tones with an SPL meter, but it's not terribly difficult. Especially now that there are affordable USB microphones suitable for the job. This should help:

Room Measuring Primer

Hi-fi is a hobby, and like any hobby the more we put into understanding it the more enjoyable it will be.

--Ethan

[JLM]

Agreed, I tried Stereophile test tones and Radio Shack spl meter (with the corrections).  Then I finally learned how to do the use my Behringer DEQ2496 (another steep learning curve) with ECM-8000 microphone - and got much better results. 

99% of audiophiles (including me) simply don't have an ear trained to do this properly.

Guy, do give nearfield a try, it's free so what do you have to lose?  And read up on the swam theory and give it a try too (you might not even need my GIK panels). 

[Guy 13]

Guy:
If your room is truly a 12'x12'x10' concrete echo echo echo box, I would suggest buying a good set of headphones.
BUT your pictures suggest you are describing the listening area only, you must also include your office area into the equation. Acoustically a curtain divider does not define the room, it is the area between the "hard" walls that is important.

Now in your real room you have four potential bass trap corners available again, the front corners are ideally suited for typical 45 degree floor to ceiling corner bass traps, the back corners are somewhat complicated by the door and the office window.
The pictures do not show the office window area clearly but the shallow alcove behind the door would also be a perfect candidate for a 6" deep flat floor to ceiling trap.

Then start on the 1st reflection side wall absorbers, curtains are a start but they have to be pretty thick, maybe backup your current setup with cheap felt/cotton shipping blankets.

We really need to see a more accurate floorplan of your actual listening "room" to make detailed suggestions.
As for the textiles required check into local industrial sources for fiberglass insulation, felt blankets ?? they may be cheaper than the local shops.

I envy you, my fingers are starting to go numb, as I type this response in my smoking area / garage, it's getting colder 4C.

Shawn

Hi Shawn and all Audio Circle members.
I have already posted some details and pictures and now,
I am waiting for your comments and suggestions.
I am waiting, I am still waiting...
Let me know if you still want to post your suggestions.
Thanks.

Guy 13

[Guy 13]

REW is a measuring software that is free. You need a computer, microphone (Behringer ECM8000 is relatively cheap and effective - in Europe anyway), microphone stand and cable. Some use a sound pressure level meter instead of a microphone.

However, REW is not simple, nor I suspect is any other decent measuring software, because it's a complicated subject.

The simplest way would be to buy a test CD with test tones (Stereophile's first one is good) and a sound pressure level meter like the ubiquitous Radio Shack one.

Both these approaches will help you position your speakers and ears for least problematic sound and will identify the areas you can improve with room treatment. If you use an equaliser as I do it can show you what settings you need.

I've been a wannabee audiophile for around nine years but it's taken me to this year to get things approaching right. I'd dabbled with test tones and SPL meters but this year I decided to do the job properly and use REW. It's tough to learn as there are so many things to go wrong and so many options, but there's good advice on their forum. I wouldn't say it was 100% accurate (I can't believe any software/microphone combination is) but it will get you near your target. The final test is always your ears.

If you plan on listening seriously for a number of years, changing rooms, houses and equipment, I recommend learning a software like REW now as it will help you well in the future.

Hi Hipper and all Audio Circle members.
I sure don't want to sound rude,
but I am not interested in complicated stuff,
that include crossover,
computer (Lap top) and anything that will make my brain overheat.
I am an old fashion guy and anything that needs new training,
is not something that I want to do, unless it's super easy
and when I say super easy,
I mean anything that does not need an instruction book.
Thanks anyway for your suggestions, I know you are trying to help.

Guy 13

[Guy 13]

Agreed, using REW is more complicated than playing test tones with an SPL meter, but it's not terribly difficult. Especially now that there are affordable USB microphones suitable for the job. This should help:

Room Measuring Primer

Hi-fi is a hobby, and like any hobby the more we put into understanding it the more enjoyable it will be.

--Ethan

Hi Ethan and all Audio Circle members.
There is a lot of interesting and informative stuff on your website.
I spent almost an hour ready only part of it.
Right now, I am gathering information to make the right move.
Because I have a very limited budget,
I want to make sure I make the right move,
especially, that this set up will probably be my last one.
Bass traps I need, I am almost positive,
almost every room need some.
Absorber panels, I might need, how many, look like many,
now how about diffuser(s) or deflector.
Both diffusers and deflectors can be purchased in Vietnam at cheap price.
Do I really need those?
Thanks for your comments, highly appreciated
and very much needed for someone like me.

Guy 13

[Guy 13]

Agreed, I tried Stereophile test tones and Radio Shack spl meter (with the corrections).  Then I finally learned how to do the use my Behringer DEQ2496 (another steep learning curve) with ECM-8000 microphone - and got much better results. 

99% of audiophiles (including me) simply don't have an ear trained to do this properly.

Guy, do give nearfield a try, it's free so what do you have to lose?  And read up on the swam theory and give it a try too (you might not even need my GIK panels).

Hi JLM and all Audio Circle.
I want to say: Thanks for your good contribution to this post
and for your offer of the GIK 244.
By the way, keep them aside, I will take them,
I just have to arrange a way to get them to Vietnam
at a cost at will not bust my small budget.
I am still reading and gathering information.
I have a Chesky or Stereophile (Or both) CD with frequencies sweep.
I don't find that very practical, therefore I got a portable
frequency generator 20-20K from the local electronic super market.
Now I need a SPL meter, I am looking on Amazon.
After making tests, even if they are not accurate,
it will give me an idea of what frequencies are creating the problem(s).
I am waiting for the cabinet maker to modify my IKEA low profile furniture,
so that it can hold all my components.
I will give a nearfield trial as soon as I can set up all my components.
I also want to make my listening room a little more smaller again.
All that will take around 2 to 3 months,
I think I am heading in the right direction.
By the way, I almost forgot, I think my reinforced ceiling with plaster
need some absorbing material, don't you think so?
Please comment, I always look forward to read your posts.
Thanks.

Guy 13

[Ethan Winer]

99% of audiophiles (including me) simply don't have an ear trained to do this properly.

It's not really possible to "measure a room" by ear alone, no matter how skilled one is. Music is not a good source because the key of the music may not align with the particular peaks and nulls of the room. So you'd have to audition different music in at least five or six keys, and there's still no reasonable way for the brain to process all of that. Further, if you move your head even a few inches everything changes. Versus room measuring software that sweeps every frequency in about ten seconds, then lets you view the results as frequency response, ringing, reverb time, individual reflections, and so forth. Of course, it helps to measure at a few locations too. But each measurement takes only a few seconds!

--Ethan

[Ethan Winer]

I sure don't want to sound rude, but I am not interested in complicated stuff

That's not rude, just honest.

Maybe you have a local friend who's knowledgeable and is willing to help you?

--Ethan

[Guy 13]

That's not rude, just honest.

Maybe you have a local friend who's knowledgeable and is willing to help you?

--Ethan

Hi Ethan and all Audio Circle members.
Yes, I am honest and direct, sometime, too direct.
No such thing as knowledgeable friend for me here.
I will explore a little more that avenue of audio computer analysis
or whatever you can it.
Thanks.

Guy 13

By the way it's a nice pussy cat you have.
They say the pets (Cats or dogs and sometime other species)
look like their master, I think in you case,
your cat has physical similarities
and take that as a compliment.

[Ethan Winer]

One of these days I'll post the "morph" photo I made of me transforming into my kitty Noah.

[MarvinTheMartian]

Guy: I'm glad your room just doubled in apparent size, now you have some room to work with.

The "Best room acoustics" by definition requires acoustic measurement tools.
You CAN drive a car without any instrumentation, but you are never sure how fast you are going, how far you have gone or when you will run out of gas.

With nothing more than a tape measure you are limited to acoustic "approximations" using one of the available on-line room resonance mode calculators.
These calculators highlight potential problem frequencies, and more importantly get you familiarized with the wavelengths / modes you are dealing with.
Normally these LxWxH spread sheet results would be very accurate for your style non-flexing concrete box, but your tapered left wall throws a compound wrench into the equation.
You might be able to enter three different Widths, min average and max into the calculator and watch the main mode ( 1,1,1) trends.

A tape measure can also help you setup your speaker and listening position. There are is a huge variety of online setup resources available.
Most if not all, suggest keeping your head and speakers out of the major room mode positions, that leaves you with preferred  0.2, 0.32, 0.45, 0.55, 0.68 and 0.8 ratios to work with.
Simply put, with your 23' length put your speakers at 23'*0.2=4.6' and your ears at either 23'*0.45=10.35' or 23'*0.55=12.65'. ( I'll leave the inches calculation to you, I'm going metric : )
These ratios apply in all 3 dimensions Length Width and Height.

Room treatments can be broken down into three main categories, bass traps, mid/high frequency absorbers and diffusers.
From your listening based "complaints" department  it sounds like bass trapping is on top of your list.
These are big and deep, because bass wavelengths are HUGE!  If you are not using a purpose built, read expensive, specifically tuned resonant bass trap, the next simplest DIY solution is fiber based bass absorber in all 8 room corners.
For the fiber based absorbers there seem to be two well documented styles prevalent on the internet, corner filled and corner straddling, either is easy to build, but you need the basic materials. The 45 degree straddling seem to be more efficient use of material, but the corner filled may be more acoustically efficient.

Your main problem is finding a cheap source or substitute for the common fiberglass based material typically used on this side of the planet.
Earlier GIK had an excellent polyester fiber suggestion, Your mission, should you choose to accept it : )  is to find a suitable cheap local textile material.

I don't normally point to other boards, but these guy's are slutz
They talk about material flow resistivity ... geeks one and all.
http://www.gearslutz.com/board/bass-traps-acoustic-panels-foam-etc/
   
 Shawn

 

[Guy 13]

One of these days I'll post the "morph" photo I made of me transforming into my kitty Noah.

Hi Ethan and all Audio Circle members.
I look forward to see that.
 

Guy 13

[Guy 13]

Hi MarvinTheMartian.
Thanks for taking the time to write this long explanation, it's appreciated.
I am looking for measuring device on the Internet or on Amazon.
I will keep informed everybody interested.
Thanks.

Guy 13 from planet Vietnam.