Best room treatment

I will also add an encouragement to read and absorb the excellent book by Earl Geddes.  I had already spent a good bit of time and effort attempting to self educate on room acoustics and psychoacoustic principles before finding the Geddes work.  As I recall, the book resulted in several "Aha" moments.  It is good enough that I have reread much of it several times. 

For those of us who are not in the business and have no formal training in room acoustics, we are trying to achieve enough understanding of the relevant principles to successfully reduce those principles to practice in a single application--our own listening room.   Most of us have jobs and families and have limited free time.   It can be hard to justify spending that precious free time self educating on acoustics rather than listening to music.  There is a reason why I remained clueless on room acoustics until I retired and had an abundance of free time.  There is also a reason why people like Jim Smith can make a living out of helping folks set up their rooms optimally.  There is a reason why a lot of serious audiophiles will just turn the decision making process over to GIK or RealTraps.  

The maxim, "knowledge is power" applies here. In my case, I can tell you that the efforts I have put into understanding small room acoustics has made me a better listener.  It has transformed that frustrating "something is not quite right here, and I don't know exactly what it is wrong much less how to rectify it, so I will spend $5000 on a new preamp and hope that fixes it" feeling to "this deviates from a live performance with respect to XYZ, and I should change ABC to rectify that change."   Five years ago I had a room full of really good equipment that sounded like crapola.  Now that same equipment sounds as good or very nearly as good as set ups I've heard that cost as much as 4x the cost of my system. 

5 years ago almarg offered the following comment on my systems page.

Speaking of the back wall, though, meaning the wall behind the listening position, a point which might eventually prove to be significant is that reflections from that wall will tend to produce a dip in frequency response at frequencies (in Hertz) in the vicinity of about 281.5 divided by the number of feet between that wall and the listener's ears. So if that distance is around 3 feet, as appears to be the case, reflections from that wall will cause a suckout, to some degree, in the vicinity of 94 Hz or so.

The 281.5 figure, btw, corresponds to 1/4 of the speed of sound in typical indoor environments, in feet/second. Rear wall reflections at a frequency of about 281.5 divided by the distance to that wall in feet will arrive at the listener's ears exactly out of phase with the direct sound arrival. The resulting suckout can be quite pronounced IME. 

In two paragraphs, Al completely changed the trajectory of my audiophile experience by  applying his knowledge to my particular application.   His guidance wasn't opinion or personal preference, it was science based fact.   Happy listening!

Hello ronboco,

     You’re getting some excellent advice from some very knowledgeable experienced audio guys and I agree with most of it. But I’m concerned that you might be getting a bit overwhelmed in the process, kind of like taking the advanced level courses before you’ve taken the basic level prerequisite classes.
     Looking retrospectively on my 45+ year audio hobby journey, I know that reading and education were equally as important as listening, selectively purchasing component parts, experiencing and experimenting while building progressively better a/v systems over the years step by step. There’s a lot to learn in this hobby and I think we progress only at a pace that our natures are comfortable with. My main concern is that being fed well intentioned audio advice at a fire hose intensity level may not be the most constructive way to assist you.
     I think your own statement, that " I definitely need some more knowledge before taking out my wallet, may be the best approach to take at least for a while. But I realize you’re probably also anxious to get started and make some immediate system improvements while you’re gaining knowledge and developing an overall plan.
     I think this is possible and a good idea. For example, after you read the referenced Geddes material you could then begin your system improvement attempts by applying his proposed solution to what he considers one of the most difficult aspects of attaining good quality home audio, which is getting the bass sounding right in the room, through the utilization of multiple subs.
     I agree with brownsfan that learning and utilizing REW would be very beneficial in general and that the $3K Audio Kinesis Swarm 4-sub complete kit distributed bass array system is a very effective and simple complete package solution for attaining high quality bass throughout your entire room, no matter its quirky dimensions.
     However, I believe you’ll get very similarly good results utilizing the ’sub crawl’ method (google it) and you’ll begin to gain the benefits of multiple subs, even with just 2 properly positioned and configured subs, although the good bass performance will be restricted to a single designated listening seat and not equally good throughout the entire room.
     I use an AK Swarm type 4-sub system in my room, here’s a link to an Absolute Sound review that contains a very accurate description of what to expect. Unfortunately, 2 subs are not capable of providing this level of bass performance.

https://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/

Best wishes and keep learning,
Tim

Hi Tim. It is quite a lot of info to take in. I’m reading Earl Geddes article right now. Thanks for your advice. I was wondering if a swarm system would eliminate the need for at least some bass trap panels therefore saving some money. 

Hello ronboco,

     When I first installed the AK Debra 4-sub distributed bass array(DBA) system in my 23’x16’ living/listening/home theater room, the only acoustic room treatments in my room were wall to wall carpeting and some padded leather furniture. The AK Debra is almost identical to the Swarm except the subs are slightly narrower and not as square. I also used no room correction software or hardware. The Debra system, however, still performed amazingly well.
     In fact it worked so well that later, when I was working with GIK to finally add some room treatments to optimize my room acoustically (that was long overdue), I was very concerned that any changes to my room might negatively effect my system’s newly achieved near state of the art bass performance. I didn’t want to jinx anything.
     But after adding GIK’s recommended stacked bass traps in all 4 corners of my room along with over twenty additional 2’x4’ absorption and diffusion acoustic panels strategically distributed on all 4 walls, the bass still subjectively sounded exceptionally good to me, I did notice a dramatic improvement in midrange, treble and stereo imaging performance in my room with the addition of the room treatments but not any discernible negative effects to the bass performance.
     I did no before and after room frequency response measurements of my room. But I suspect, if I had, they would show significant improvements in bass response after the addition of the swarm DBA, which was maintained after the addition of the extensive GIK room treatments along with significant improvements in midrange and treble performance post room treatments.
     So, what have I learned from all this and what does it mean for your room? My current thoughts are the following:

1. Just because I subjectively noticed no significant positive or negative effects to bass performance of the swarm with the addition of the numerous bass traps in my room, and since I performed no objective before and after room frequency response measurements, I can’t definitively state there were no improvements in bass frequency response performance in my room.
2. I have learned that improving measured bass frequency response in a room can have positive effects on measured midrange frequency response, which is subjectively perceived as increased midrange clarity and detail.
I definitely perceived increased midrange, treble and stereo imaging performance after the installation of the room treatments. But again, I can’t be certain whether these improvements were primarily the result of the bass traps or the numerous midrange/treble absorption and diffusion panels in the room. I suspect the improvements are the result of a combination of both.
So for your room, I don’t think you’ll need bass traps initially but, once you’re ready to install room treatments for midrange and treble performance, it’s probably safer and best to also include bass traps. Or you could treat it as a learning experiment by installing the bass traps last and determining whether you subjectively perceive any changes to midrange, treble and stereo imaging performance after installing them.

3. I believe before and after objective room frequency response measurements are very important for clearly, accurately and objectively understanding how well your system is performing and the effectiveness of any added room treatments.
I regret not doing them and suggest you may as well.

Best wishes,
Tim

Hello Tim ,

    I am now thoroughly excited about the swarm system. I’m going to beg borrow and steal for some more money. I am wondering though if our room is just not good enough to achieve the sound quality I’m hoping for. 18 ft. High ceilings with windows on the right side and stairs and upstairs walkway on the other. There are really only two corners for bass traps and only 4 inches between the wall and windows so I could not stack all the way to the ceiling. It would be a top, middle , bottom trap set up of about 2 ft sections. We are running curtains from the top window to the floor on both sides. The fireplace is in the middle so any wall treatments would have to start about 6 ft up.  In regards to the 2’x4’ panels from GIK did you use strictly absorption and diffusion? It seems they have some that have a combination of each characteristic. Do you think panels will be needed all the way to the top or will about half way up be sufficient. I’m assuming the ceilings will also need some panels. One of the videos I watched recommended absorption and diffusion on the ceiling.