A Must Read by everybody

[warnerwh]

who wants to know how to make their systems sound much better. This issue of Absolute Sound is actually touting the benefits of equalization and dsp. They give a good amount of discussion on the subject. For people that haven't been in this hobby you'll find it interesting to know that the frequency response of a typical room can easily measure plus or minus 15db. Amps, preamps and cd players are virtually flat but your room is what makes things sound bright or dull and/or boomy etc etc.If you get rid of just some of the big problems the sound of your system will increase to a level nearly matching getting significantly better speakers. The timbre of instruments will be more realistic and vocals will sound dramatically improved. I can't recommend enough the effect of a good room and some sort of equalization. Learn about rooms and acoustics and you can make your 2,000 dollar system make your friends 10,000 system sound wanting. Also the owner will sure want to know how you did that. This is NOT and exageration unless you happen to be the luckiest person on the planet.

 

[plhart]

Bingo! This is the exact reason for our CEDIA Seminar series. Read parts 1 & 2 available now on the site. Part 3 Room Acoustics: Room Treatments is due to go on-line late this week or early next week. It was taught by Tony Grimani who has done over 150 high end home theaters over the last 14 years. He shows us how he does it. That's what this section is all about!

 

[mtrycrafts]

Bingo! This is the exact reason for our CEDIA Seminar series. Read parts 1 & 2 available now on the site. Part 3 Room Acoustics: Room Treatments is due to go on-line late this week or early next week. It was taught by Tony Grimani who has done over 150 high end home theaters over the last 14 years. He shows us how he does it. That's what this section is all about!

Link please too much of a maze to navigate

 

[mtrycrafts]

who wants to know how to make their systems sound much better. This issue of Absolute Sound is actually touting the benefits of equalization and dsp. They give a good amount of discussion on the subject. For people that haven't been in this hobby you'll find it interesting to know that the frequency response of a typical room can easily measure plus or minus 15db. Amps, preamps and cd players are virtually flat but your room is what makes things sound bright or dull and/or boomy etc etc.If you get rid of just some of the big problems the sound of your system will increase to a level nearly matching getting significantly better speakers. The timbre of instruments will be more realistic and vocals will sound dramatically improved. I can't recommend enough the effect of a good room and some sort of equalization. Learn about rooms and acoustics and you can make your 2,000 dollar system make your friends 10,000 system sound wanting. Also the owner will sure want to know how you did that. This is NOT and exageration unless you happen to be the luckiest person on the planet.

What? From TAS? Do they have a new editor? The old had a revelation?

So out of character for them. If this is an indication of things to come, it is interesting.

 

[warnerwh]

It's interesting that REG has admitted to using equalizers for years, mostly digital he says. The article that is called "Room Acoustics-Audio's Final Frontier" just kills me. Room non linearities have been known about for decades. The high end audio media made such a huge deal about anything in the signal path and now they tout digital equalizers that need a/d and d/a conversion, talk about adding circuitry to the signal path compared to simple tone controls.
I think it's about time these people told some truth. Anyway room acoustics are something to spend time and money on and get much better sound. And for people who haven't tried room treatment/correction you're in for a treat. The results are audible and your room can easily be made superior to what you had. It is easy to best a system that costs twice as much with a good room against a poor room with very expensive equipment. A new set of speaker cables or interconnects will only look different and leave you less money for what really matters.
I'm new here, I will check out the Cedia series. Glad to see someone is trying to honestly help people. Cheers

 

[Unregistered]

It's interesting that REG has admitted to using equalizers for years, mostly digital he says. The article that is called "Room Acoustics-Audio's Final Frontier" just kills me. Room non linearities have been known about for decades. The high end audio media made such a huge deal about anything in the signal path and now they tout digital equalizers that need a/d and d/a conversion, talk about adding circuitry to the signal path compared to simple tone controls.
I think it's about time these people told some truth. Anyway room acoustics are something to spend time and money on and get much better sound. And for people who haven't tried room treatment/correction you're in for a treat. The results are audible and your room can easily be made superior to what you had. It is easy to best a system that costs twice as much with a good room against a poor room with very expensive equipment. A new set of speaker cables or interconnects will only look different and leave you less money for what really matters.
I'm new here, I will check out the Cedia series. Glad to see someone is trying to honestly help people. Cheers

Room accoustics has been well acknowledged by many serious audiophiles as contributing heavily to the sounds that finally gets to their ears. Getting the transparent and most neutral home playback gears and speakers is probably just a third of the effort to achieving sonic nirvana. The other third is getting the best possible record mixes. And the last third would be the room accoustics.

To many die-hard audophiles, treating the room to eliminate those early reflections and using bass traps to overcome room nodes is the only way to bring out the transparency of their gears. Using equalization, whther digital or analog, and DSP to correct for room accoustic problems is considered anathema. While you may get a flat response in your listening position, those equalizers and DSP just made mincemeats of the signals that an audiophile wants to hear in their original conditions the way the recording engineer had intended them.

AV_PHILE

 

[JoeE SP9]

Room treatment should come first. If you still require Eq with a DSP or whatever then that kind of correction can be applied after. Room treatment first always. With some sensible selection and positioning you can have a visually acceptable appearance along with the increased sound quality that room treatments give.

 

[Mudcat]

Room non linearities have been known about for decades.

Does anybody remember the James Bond Film "Diamonds Are Forever"?

In the later part of the movie, there is a fight scene between Bond and two women "Bambi" and "Thumper".

We remember that part?

If you observe the room arrangement, you'll notice it is open onto a deck. During the fight, some metal cylinders are knocked over. Those cylinders were there for acoustic treatment. Not related to the film, but so the owner can listen to his stereo (which is not shown).

Just an observation of old acoustic treatments.

 

[warnerwh]

"Room treatment should come first. If you still require Eq with a DSP or whatever then that kind of correction can be applied after. Room treatment first always. With some sensible selection and positioning you can have a visually acceptable appearance along with the increased sound quality that room treatments give."

This may be true but if you are striving for the very best your system is capable of then it's quite likely equalization/DSP will probably be necessary. It would take an awful lot of room treatment to do what I want and that's in a room with decent dimension ratio's, LEDE treatment and bass traps. Also I'm referring to making the sound the best it can be to your ears, not a perfectly flat response as most people, myself included, find a flat response bright on top and thin on the bottom. The bottom line is the more you can control the room problems the better. An equalizer/DSP will make this more complete than room treatment alone.

 

[Rip Van Woofer]

Hmmm...wonder if those metal cylinders were Helmholz resonators?

According to my Handbook of Acoustics, Helmholz resonators (a proportionally large cavity with a small opening to aborb specific frequencies) have been used for millenia although the theory was not known of course: he cites the use of large bronze jars in the ancient Greek theater and small-necked pottery jars set in the walls of an old cathedral (in Sweden, I think) with the openings flush to the wall. And they're still used as bass traps today of course.

And if you've been in a gym, church, or other fairly modern building with cement block walls that have little slits in them: yep, another application of the Helmholz resonator. Same phenomenon is why you can blow across the mouth of a beer or wine bottle (or old school Coke bottle) and make a note; that's the resonant frequency.Just by way of illustration and for fun, the author of the Handbook includes a quick calculation of how many Coke bottles it would take to reduce their resonant frequency in a room of given volume by x dB.

Always glad to contribute more useless trivia!

Oh, yeah, the room and speakers rule as far as what determines your system's audio quality. Given the choice between (say) a $2k amp upgrade or $2k for room acoustics the latter choice should be a no-brainer.

BTW, my own room sucks; I've done some treatment. But I think the ultimate answer lies in my unfinished basement...

 

[warnerwh]

"According to my Handbook of Acoustics, Helmholz resonators (a proportionally large cavity with a small opening to aborb specific frequencies) have been used for millenia although the theory was not known of course: he cites the use of large bronze jars in the ancient Greek theater and small-necked pottery jars set in the walls of an old cathedral (in Sweden, I think) with the openings flush to the wall. And they're still used as bass traps today of course."

Please allow me to quote you. This I find very interesting and would like to post it and email it to Robert Harley. Thanks, Warner

 

[plhart]

Minimum phase response systems include woofers, midranges and tweeters in their useful frequency range, and room resonances at low frequencies. Therefore, when a room resonance is addressed with an equal and opposite parametric EQ filter; that is, when the equal and opposite amplitude response is dialed in on a subwoofer, the resonance is corrected and the subwoofer/room "system" remains minimum phase. The system's transient response is also fixed.

Above approximately 125Hz the pros prefer to use passive acoustic room treatment in conjunction with "flat response" on-axis loudspeakers which exhibit the excellent polar response characteristics of linear but gradually declining response with increasing frequency.

These topics will be covered in more depth in the upcoming CEDIA Seminars; Part 3 with Tony Grimani speaking on "Room Acoustics: Acoustic Treatments" and Part 4 which features Dr. Floyd Toole speaking on "Room Acoustics: The Room and Loudspeaker System".

 

[Rip Van Woofer]

Warner: Rather than quote me, here's the source. It's on page 216 of Master Handbook of Acoustics, Fourth Edition, by F. Alton Everest.

"In Helmholz resonators, we have acoustical artifacts that far antedate Helmholz himself. Resonators in the form of large pots were used in ancient times by the Greeks and Romans in their open-air theaters. Apparently they were used to provide some reverberation in this nonreverberant outdoor setting...

"More recently (that is, in medieval times) such resonators were used in a number of churches in Sweden and Denmark*. Pots like those those of fig. 9-30 [on p. 217] were embedded in the walls, presumably to reduce low-frequency reverberation that is often a problem in churches. Ashes have been found in some of the pots, undoubtedly introduced to 'kill the Q' of the ceramic pot and to broaden the frequency of its effectiveness."​

*Everest here cites Brüel, Per V., Sound Insulation and Room Acoustics, London, Chapman and Hall (publ.), 1951. Wonder if that's the Brüel of Brüel and Kjaer? (sp?)

 

[FLZapped]

Hmmm...wonder if those metal cylinders were Helmholz resonators?

According to my Handbook of Acoustics, Helmholz resonators (a proportionally large cavity with a small opening to aborb specific frequencies) have been used for millenia although the theory was not known of course: he cites the use of large bronze jars in the ancient Greek theater and small-necked pottery jars set in the walls of an old cathedral (in Sweden, I think) with the openings flush to the wall. And they're still used as bass traps today of course.

To add to this, I believe they tuned them with sand, or sometimes broadened their response with ashes.

My room is so-so, but because it must pass the "wife" factor there is a limit to what is allowed.......

Luckily, there are heavily stuffed couches, bookcases and other furniture that adds dispersion, but I still have some echo problems in the long dimension of the room. However, that is 90 degrees off from my listening position and the direction my speakers face.

-Bruce

 

[warnerwh]

Rip Van Woofer, I thank you. That is very interesting. I emailed Robert Harley regarding what they title the "Final Frontier in Audio" in the latest Absolute Sound. Doubt I'll get a response but it's certainly something for him to think about. Acoustics are old news. There are some great DSP pieces out and more to come. It's even more interesting than wire. Hopefully they will spend more print in the direction of acoustics. Cheers

 

[ned]

What about Michael Green and Eight Nerve Room treatment concept and tunable products? Any scince behind it.

Michael Green

Eight Nerve

 

[plhart]

Ned-

Please read The CEDIA Seminars - Part 3 "Room Acoustics: Acoustic Treatments". There the science of room acoustics is explained without any snake oil added.

Products that work effectively for acoustic absorption are materials such as fiberglass and mineral wool covered by an acoustically transparent cloth which will let the sound waves inside. Once inside, the sound wave's energy is dissipated by the fibers of the material and turned into heat. A 1" thick "pillow" will only absorb down to 1000 Hz. It takes 2" to absorb down to 500Hz and 4" to get down to 250Hz. Imagine how much thickness it would take to absorb a 50Hz bass wave?

Secondly, read the section in Part 3 about first reflections. And third, look at the illustrations at the end of the article. Do you see any little pads in the room corners? No. Because the mid and high frequencies we're talking about controlling are controlled by careful placement so that we don't hear the problems at the listening position.

The room corner's and junctions of ceiling and walls are powerful in that they interact with low frequencies and set up room modes (aka standing waves or low frequency reverberation). Part 3 talks about how to control these problems also.

Bottom line is that there is no magic material that absorbs "better". It takes more thickness to get down lower in frequency. Then you go to diaphramatic absorbers. And that's another story...

 

[mtrycrafts]

What about Michael Green and Eight Nerve Room treatment concept and tunable products? Any scince behind it.

Michael Green

Eight Nerve

Interesting that I didn't notice Michael Green's academic credentials to know what he is talking about acoustics other than being involved with music? Mabe a degree or two in science of acoustics? But, I could have missed it too.

 

[ned]

Thanks a lot for your reply. I totaly agree with you. The only thing that is disturbing is users of such sound treatments provide such great reviews about their products. Audio Circle has a forum just dedicated to their products and consumers sing praises to them!

Talking about squeezing your speakers and component with their clamps like squeezing juice out of an orange to tune them !??

 

[Mudcat]

he cites the use of large bronze jars in the ancient Greek theater and small-necked pottery jars set in the walls of an old cathedral (in Sweden, I think) with the openings flush to the wall. And they're still used as bass traps today of course..

Those in Sweden and Denmark were Viking versions of toilets and those in Greece and Roman theaters were vomit basins.