room acoustics for beginners

[hardcore_gamer99]

how and where do i learn room acoustics basics to advanced levels. i want to do this hifi audio business in my country. So want to learn everything

 

[NTK]

You can start with this book. But note that a new edition is coming out very soon (this year).

Sound Reproduction | The Acoustics and Psychoacoustics of Loudspeakers

Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms, Third Edition explains the physical and perceptual processes that are involved

www.taylorfrancis.com

 

[DVDdoug]

Yes! The Toole book is surprisingly "readable" and it has LOTs of good information. I expected it to be more technical & mathematical. It's not "advanced" acoustics, and personally I didn't want to get that deep into it anyway... I've forgotten most of my advanced math.

i want to do this hifi audio business in my country.

Acoustics is a very small part of the "hi-fi business". It's a specialty business mostly for people (rich people ) building home theaters, dedicated listening rooms, or for performance spaces, etc. I think Amir's company (madronadigital) does the whole thing, selling & installing the electronics and handling the acoustics.

Architects & contractors often hire an acoustician as a consultant or as a subcontractor.

A lot of people here do their own measurements and then buy acoustic treatment materials from the companies that make & sell that stuff.

So want to learn everything

A good book that covers "everything" is The Audio Expert by Ethan Winer. He's in the acoustic treatment business (RealTraps) but the book pretty-much covers everything.



...As you may know, the "audiophile community" is mostly crazy! This is one of the few rational-scientific resources. Ethan Winer's Audiophoolery is worth reading. Even if you remain on the scientific side, you'll need to understand the crazy side and perhaps walk a thin line... Some of them may be your best customers!

 

[Kal Rubinson]

The classic: Master Handbook of Acoustics by Everest and Pohlmann.

 

[Duke]

"Premium Home Theater: Design and Construction", by Earl Geddes. The acoustic and psychoacousic information is excellent, while the video system information is outdated in some respects.

This book is out of print (and currently listed at $100 on Amazon) but the entire book can be downloaded for free as a .pdf file. Here is the link:

http://www.gedlee.com/downloads/HT/Home_theater.pdf

In particular I suggest chapters 2, 4, 5, and 6.

 

[hardcore_gamer99]

Thanks a ton everyone but i am a but dumb. Cant understand things easily. So which is best for beginners which has very easy language.

 

[Duke]

Thanks a ton everyone but i am a but dumb.

Me too. So let me try to write a brief introduction, and hopefully that will help you get started learning from someone else who isn't as dumb as me.

Room acoustics for home audio is almost like two different subjects: One subject would be room acoustics at low frequencies, and the other subject would be room acoustics at middle and high frequencies combined.

At low frequencies, the room reflections result in big peaks and dips in the frequency response. These peaks and dips change when you change either your location or the speaker's location, but they never entirely go away. The peaks are especially bad because they can make the bass sound boomy or muddy.

The higher in frequency we go, the closer together these peaks and dips become. Eventually they become so close together that your ears can no longer distinguish the individual reflections; rather, you hear the average of the reflections because they all blend together.

The frequency where the transition happens between "you can detect the individual peaks and dips" and "all you can detect is the average of many peaks and dips" is called the "Schroeder frequency", after the guy who figured it out. But it's actually a fuzzy transition zone rather than a sudden change that happens at a certain frequency. In home audio listening rooms the transition zone is usually centered somewhere between 150 Hz and 400 Hz (in general the bigger the room, the lower the Schroeder frequency).

So below the transition zone we have to deal with big peaks and dips that tend to change from one location to another throughout the room. These peaks and dips dominate what we perceive at these frequencies. Even if the speaker's bass response started out perfectly flat, the room's inherent reflection patterns (called "modes") will cause big peaks and dips and that is what we hear.

Above the transition zone the frequency response of the reflections looks like the off-axis response of the speaker, and what we hear is in effect a "weighted average" of the direct sound and these reflections, with the direct sound usually having a lot more influence than the reflections. So above the transition zone the reflections don't dominate like they do at low frequencies, but they still have a strong effect on what we perceive.

There is much more to this topic, this has been just a very quick introduction. Here's a link to an article about how to get good sound below the transition zone written by somebody much smarter than me:

Subwoofer / Low Frequency Optimization

Subwoofer / Low Frequency Optimization By Amir Majidimehr [Note: This article was published in the May/June 2012 issue of Widescreen Review Magazine] Do you remember the scene in the movie Stargate where Daniel Jackson decodes the symbols that allow them to open the Stargate to travel to...

www.audiosciencereview.com

And here's another article by the same smart guy, who happens to be the founder of this website, this time he's writing about sound above the transition zone:

Perceptual Effects of Room Reflections

Perceptual Effects of Room Reflections By Amir Majidimehr [Note: This article was originally published in the Widescreen Review Magazine, titled "it is not simple!"] When Gary Reber asked me to write an article for the 20th anniversary of Widescreen Review magazine I was stumped at first...

www.audiosciencereview.com

 

[Keith_W]

All these books on acoustics that have been suggested so far can be easily understood by anybody with a high school level education.

OTOH the advanced stuff that I occasionally hear from NTK and Rene@acculution blows my mind and makes me feel stupid. Real and imaginary numbers, Heyser's corkscrews, particle velocity and pressure not being in phase, and so on. It makes me realise there is a whole level I have not explored and have no understanding of. For example, Toole's book only mentions the difference between nearfield and farfield extremely briefly. He does not explain why the volume oscillates until it stabilises at a certain distance before it starts falling according to the inverse square law. Nor do I recall him mentioning that it is frequency-dependent. (Note, I am mentioning this as an example, I am not looking for an explanation for this phenomenon in this thread!).

I think the books mentioned so far are probably advanced hobbyist level or basic pro level and does not delve into the cutting edge of what is known about acoustics. For that, you need guys like NTK to drop in now and then to remind you of how little you actually know!

 

[MaxwellsEq]

Thanks a ton everyone but i am a but dumb. Cant understand things easily. So which is best for beginners which has very easy language.

I'm sure you will be fine! The core of understanding anything is being interested in it and taking small steps to grasp it. You are already 50% of the way there!

 

[hardcore_gamer99]

I'm sure you will be fine! The core of understanding anything is being interested in it and taking small steps to grasp it. You are already 50% of the way there!

dali opticon 2 mk2 L,R,L+R AND SUBWOOFER i have dirac live with bass control. Should i bump or lower any frequency of speaker or subwoofer in dirac? help will be apperciated. speaker crossover is at 80hz managed by dirac not me

 

[hardcore_gamer99]

Where do i learn from basics to advance. Then i want to treat my own room which is normal bedroom and pb 2000 rpo has null at 45hz frequency. Room 11.7x10.7x10

 

[Jim Taylor]

There are several ways to attack this problem. One is to first learn measurements, such as REW:

Room Measurement Tutorial for Dummies Part 1

There are few more things transformative in audio than learning how room acoustics works. You never look at any system the same again. Like moving from film photography to digital, measurements give you instant feedback on what your system is doing. Even if you choose to not make any changes...

www.audiosciencereview.com

Room Measurement Tutorial for Dummies Part 2

Room Measurement Tutorial for Dummies Part 2: Selecting a Measurement Microphone I hope everyone has read the first part of this tutorial on downloading and installing Room EQ Wizard. Here is the link to that if you missed it...

www.audiosciencereview.com

The most obvious benefit from this sort of equalization is in the bass, which is explained here;

Speaker Placement 101: Is Speaker-Boundary Interference Killing Your Bass?

Not hearing enough bass through your monitors? The distance between your room boundaries and speakers has a huge impact on your bass performance. This tutorial will show you specific strategies for placing your speakers to get a balanced bass response.

arqen.com

... and the reason for the emphasis on the bass is explained here:

Divide and Conquer - The Schroeder Frequency | Prosoundtraining

Not all sound energy in a room is reverberation. The Schroeder frequency divides the spectrum based on sound wave behavior.

www.prosoundtraining.com

A fairly good acoustics vizualizer is this one from GIK:

Perfect Acoustic Room Design with Our 3D Visualizer | GIK Acoustics

Explore acoustic room design with our Room Acoustics Visualizer. Create 3D models, place GIK products, and use VR/AR to optimize sound and visuals.

www.gikacoustics.com

... which is explained here:

Another beneficial tool is the amroc room mode calculator:

amroc - THE Room Mode Calculator

HTML5 room mode calculator. Read and hear the tune of axial, tangential and oblique modes. Scientific sources included.

amcoustics.com

... and here is another ASR thread that might be helpful, from our member @NTK :

Visualizing How Different Loudspeaker LF Directivity Patterns Couple to Room Modes

This opening post is to demonstrate how different loudspeaker low frequency directvity patterns couple to our room modes. If you are unfamiliar with what room modes are, please refer to @DonH56's excellent thread for an in-depth introduction...

www.audiosciencereview.com

Various interconnected facets of acoustics for music is covered in easily-understood language here:

The ultimate beginner's guide to room acoustics

A little knowledge and application goes a long way in fine-tuning the acoustics of your studio space

www.musicradar.com

Hope this helps!

 

[Bjorn]

Gearspace forum is pretty good with at least a good amount of people with proper knowledge. Or it used to be at least, haven't been active there for a while.

I would also recommend the books below.

https://www.amazon.com/Sound-System-Engineering-4e-Fourth/dp/0240818466

https://www.amazon.com/Acoustic-Absorbers-Diffusers-Theory-Application/dp/0415471745

A lot of stuff on internet is quite misleading IMO. A lot of confusion around small room acoustics. Might be better to hire someone who can show real results with measurements. I work with small room acoustics FIY.

 

[boxerfan88]

Room 11.7x10.7x10

Wow … almost a cube. There should be a giant peak and a giant null.

 

[Jimbob54]

Where do i learn from basics to advance. Then i want to treat my own room which is normal bedroom and pb 2000 rpo has null at 45hz frequency. Room 11.7x10.7x10

Please don't create multiple duplicate /similar threads on. I've merged 2 of yours . Thanks

 

[hardcore_gamer99]

Wow … almost a cube. There should be a giant peak and a giant null.

20dbfs null at 45hz and no peak

 

[Esprit]

how and where do i learn room acoustics basics to advanced levels. i want to do this hifi audio business in my country. So want to learn everything

University courses.