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room acoustics for beginners

hardcore_gamer99

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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
 
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! :D :D 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!
 
"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 The acoustic and psychoacousic information is excellent, while the video system information is outdated in some respects.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:


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


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:

 
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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!
 
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!
 
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
 

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


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


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


A fairly good acoustics vizualizer is this one from GIK:


... which is explained here:


Another beneficial tool is the amroc room mode calculator:


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


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


Hope this helps! :)
 
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.


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.
 
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
 
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