Your expensive room treatments might probably making your system sound worse (and why you need to read the attached article)

[microstrip]

A very interesting and challenging article. Surely I felt very happy seeing the name of Floyd Toole being referred with great praise eight times in the text and knowing his research and his book "Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms" were the basis of this method. I extensively commented on this book many times in this forum along the years, it is always nice to read from someone who shares my enthusiasm for it.

Having read and studied the Toole book, the Jim Smith book , the Sumiko method and David Wilson WASP method, my current placement method is an hybrid of those techniques, curiously also incorporating some of the priorities and methods outlined in the Richard Mak article. His explanation of the use of the Isotek castanets is clear and comprehensive - I use a similar track of an french Diapason CD test disk - and I found the section on soundstage width particularly relevant :

"It is important to note that in the RCA Living Stereo Rhapsodies/Stokowski recording, the width of the soundstage is perceived to be wider than the physical width of the room, regardless of how narrow or wide the room is. A correct stage should not be limited by or determined by speaker width. The accurate spatial dimension of the recording venue should determine it. The speaker’s width, walls or the room should not limit the recreation of the acoustic space when you have found the correct position for the speaker."

This aspect, as well as bass definition and envelopment have always been my priorities.

In my opinion, not everything is perfect in the article, as could be expected. The excessive focus on the left/right channel mistake and some specific poorly treated or assembled systems is annoying and betrays on the main message of the article. I (and F. Toole and many others, BTW) disagree on the unnecessary importance given to the golden ratio dimensions and unfortunately the pictures involving 200 Hz are not correct and are misleading, omitting the problem of nulls due to wave cancelation - the worst problem of big speakers in small rooms. These pictures do not evidence what are the conditions for room coupling and the dependence of frequency on it.

We should praise the pedagogic character of soundstage section, filled with very good examples and images of very relevant image attributes.

All in all, a very good article, that unfortunately takes more time to read and meditate than most audiophiles want to spend in these matters. The reference to precise tracks and specific aspects is of great help for those of us wanting to try something new in their systems. My suggestion - go through it, purge the unnecessary gossip parts, print it in a large font and try it in your system. I will do it soon.

 

[Al M.]

Jim Smith locates the chair by running pink noise through the system and then looking at the Studio Six RTA. You move the chair back and forth on the center line until the RTA is smoothest in the bass and lower midrange region.

The problem is that if the speaker position is not optimal for the test, then the apparent smoothest response from the chair may be where its position neutralizes a bump from the speaker, i.e., it sits at a position where there is a counter-response to the speakers' uneven output. Once the speaker is positioned more optimally and has smoothed out in the room, the smoothest position for the chair may then be elsewhere than indicated in the initial test.

In that sense it really is a chicken and egg conundrum as Walnut Horns suggested.

 

[Kingrex]

I read the article again and was lost at the start with Bass. I have open baffle dipole speakers. If I walk between my speakers, there is a large null point between the speakers. At one time I moved the speakers back and forth to see what happened to the bass. I move my seat some to see what happens with the bass. I don't see any other way.

 

[Walnut Horns]

The problem is that if the speaker position is not optimal for the test, then the apparent smoothest response from the chair may be where its position neutralizes a bump from the speaker, i.e., it sits at a position where there is a counter-response to the speakers' uneven output. Once the speaker is positioned more optimally and has smoothed out in the room, the smoothest position for the chair may then be elsewhere than indicated in the initial test.

In that sense it really is a chicken and egg conundrum as Walnut Horns suggested.

Exactly my point Al. Curious what others think.

 

[TonyW]

I read the article again and was lost at the start with Bass. I have open baffle dipole speakers. If I walk between my speakers, there is a large null point between the speakers. At one time I moved the speakers back and forth to see what happened to the bass. I move my seat some to see what happens with the bass. I don't see any other way.

One thing I learned is the distance between the speakers affects the null point of the bass. In my case moving the speakers closer together moved the null point higher, approaching the ceiling which made the bass better at listening height. I was moving the speakers an inch at a time and then down to 1/4 inch increments. The difference was significant in the bass region. Roon shows I have played a few tracks over a hundred times. It takes perseverance- or maybe I am a slow learner…

 

[Al M.]

Roon shows I have played a few tracks over a hundred times. It takes perseverance- or maybe I am a slow learner…

It does take perseverance.

I also found that it may be good to play a bunch of very different and critical musical material, carefully selected based upon experience gained, any time the speakers (or the chair) are moved. Maybe not all tracks each time, but still. This takes time to evaluate.

What may work for most tracks may cause an issue or slight diminishment with another. It's like juggling many balls, there are so many things to potentially consider, for example:

Bass (low, mid, upper; amount and articulation), rhythm & timing (your favorite rock, jazz or funk track, or whatever), power in the low midrange (e.g, left hand piano, or the orchestral power range like trombones and tuba), vocal transparency, sheen on orchestral strings and, in the very upper range, triangles, cleanness of sound (the room may distort differently based on the position of the speakers, especially at high playback volume), detail, soundstage, projection of sound energy into the room, immediacy on small-scale material, scale and hall ambience on orchestral music.

And so on, whatever in particular is important to you.

 

[ecwl]

The problem is that if the speaker position is not optimal for the test, then the apparent smoothest response from the chair may be where its position neutralizes a bump from the speaker, i.e., it sits at a position where there is a counter-response to the speakers' uneven output. Once the speaker is positioned more optimally and has smoothed out in the room, the smoothest position for the chair may then be elsewhere than indicated in the initial test.

In that sense it really is a chicken and egg conundrum as Walnut Horns suggested.

While what you said is theoretically true, my personal experience is that this is rarely the case.

When you move your RTA/iPhone to find the optimal seat, if your speakers aren’t in an optimal position, you won’t find a seating position with perfectly smooth bass. You’ll find a spot with smooth bass, but there’ll still be peaks and troughs you can’t smooth out. Moving your speakers forwards and backwards (and maybe sideways) can smooth out these issues and improve the sound. If you try to optimize your seating position further, it’s rare that you can.

On the other hand, if you try to optimize bass response by moving the speakers first, you may still have trouble getting smooth bass after moving your seating position. In this case, you’ll need to move the speakers again.

If you’re sitting in a 60Hz null in the room, speaker movement won’t improve it. But if your speakers are on a 60Hz peak or trough, moving them will smooth out the bass. Moving the seating position first is better, even though it sounds like a chicken and egg conundrum.

 

[Elliot G.]

It is easy to mix up the cables when wiring a system. But is should be very easy to find that there is a probem once the system starts playing. As soemone earlier pointed out, play just about any orchestral piece and if the violins are not on the left then it is highly, highly likely there is an issue. But almost any track you are familiar with will work. In a jazz piece for example, is the trumpet on the left or rigt. Etc.

I know the left/right thing was part of the article but I think his point really is that there are a very high percentage of systems where the owner is not paying nearly enough attention to the details. If they have left and right mixed up then what are the odds they have spent very much time trying to optimize speaker position or anything else in the system?

one can easily use a test disc or a test stream to identify the channels. It only takes 10 seconds.

 

[Elliot G.]

It does take perseverance.

I also found that it may be good to play a bunch of very different and critical musical material, carefully selected based upon experience gained, any time the speakers (or the chair) are moved. Maybe not all tracks each time, but still. This takes time to evaluate.

What may work for most tracks may cause an issue or slight diminishment with another. It's like juggling many balls, there are so many things to potentially consider, for example:

Bass (low, mid, upper; amount and articulation), rhythm & timing (your favorite rock, jazz or funk track, or whatever), power in the low midrange (e.g, left hand piano, or the orchestral power range like trombones and tuba), vocal transparency, sheen on orchestral strings and, in the very upper range, triangles, cleanness of sound (the room may distort differently based on the position of the speakers, especially at high playback volume), detail, soundstage, projection of sound energy into the room, immediacy on small-scale material, scale and hall ambience on orchestral music.

And so on, whatever in particular is important to you.

Personally my chair gets moved after I am finsihed with my speakers 100 percent of the time in 50 percent of the cases LOL. Thanks Yogi! Guys do not forget that perfect is the enemy of great. This process takes time and does have personal preferences which are quite different. The fact that people perfer different sounds and to be honest many of which I personally don't understand but it is not my system nor my choice.
How can for example people go to a show and equal percentages of people think a room was great and terrible at the same time? Does music sound so different to everyone? are some people totally wrong? Are there other factors that determine this? Is this a lack of education?
Much to me on WBF is Paralysis by analysis.

 

[microstrip]

(...) In that sense it really is a chicken and egg conundrum as Walnut Horns suggested.

Not in my experience. I start with the speakers in the corners in order to maximize the room resonance modes and find the better acceptable place looking at the spectra. Surely it is an interactive process - after placing the speakers in position I do some corrections to the listening position.

However my experience relates to my room and my speakers - your experience can be different.

 

[Robh3606]

The problem is that if the speaker position is not optimal for the test, then the apparent smoothest response from the chair may be where its position neutralizes a bump from the speaker, i.e., it sits at a position where there is a counter-response to the speakers' uneven output. Once the speaker is positioned more optimally and has smoothed out in the room, the smoothest position for the chair may then be elsewhere than indicated in the initial test.

There is also another issue. Pink Noise is random and not cyclic so it averages. I have used RTA's plenty of times to set-up driver levels in biamp and other active systems. It's great for this but if you do a slow sine sweep you get a completely different result. Same with a test set-up like CLIO using impulse or sine. The sine sweep is slow enough to engage the primary room resonance's that an RTA misses.

You can easily measure the peaks and dips using an SPL meter while you run the sweep.

Rob

 

[sbnx]

I read the article again and was lost at the start with Bass. I have open baffle dipole speakers. If I walk between my speakers, there is a large null point between the speakers. At one time I moved the speakers back and forth to see what happened to the bass. I move my seat some to see what happens with the bass. I don't see any other way.

Rex, he is suggesting a way in which the speaker position is held constant an you move to find the spot. Then once you find that spot you would place the speaker there. This is a similar idea to the subwoofer crawl where the subwoofer is placed int he listening postion and you crawl around on the floor looking for the best spot. If you are having issues with this method then I would suggest you use something like the "Sumiko method". Push the right speaker back and turn it away. Then use the Jennifer Warnes track and slowly pull the left speaker forward. You will find a spot where the upright bass is clearly better. It has better articulation (less overhang) and is louder. This is a slow process. It may take you an hour or two to find the right spot. Especially for someone who is not used to looking for it. There is just no getting around that.

 

[Al M.]

There is also another issue. Pink Noise is random and not cyclic so it averages. I have used RTA's plenty of times to set-up driver levels in biamp and other active systems. It's great for this but if you do a slow sine sweep you get a completely different result. Same with a test set-up like CLIO using impulse or sine. The sine sweep is slow enough to engage the primary room resonance's that an RTA misses.

You can easily measure the peaks and dips using an SPL meter while you run the sweep.

Rob

Oh yeah, sine sweeps are brutal .

 

[Bruce B]

I am curious. How do you find rooms with the channels reversed but the exhibitors don't know it?

I have been asked several times to be a Judge at DIY Speaker Contests... Some of the tracks we use have things we can catch immediately whether the channels are reversed.... like MJ - Thriller.... MJ walks from R - L across the room. I also choose 1 or 2 cuts made from Q-Sound. That's a big indicator on soundstage whether a speaker can properly reproduce the sounds coming from extreme L/R or even behind you!

 

[Kingrex]

Rex, he is suggesting a way in which the speaker position is held constant an you move to find the spot. Then once you find that spot you would place the speaker there. This is a similar idea to the subwoofer crawl where the subwoofer is placed int he listening postion and you crawl around on the floor looking for the best spot. If you are having issues with this method then I would suggest you use something like the "Sumiko method". Push the right speaker back and turn it away. Then use the Jennifer Warnes track and slowly pull the left speaker forward. You will find a spot where the upright bass is clearly better. It has better articulation (less overhang) and is louder. This is a slow process. It may take you an hour or two to find the right spot. Especially for someone who is not used to looking for it. There is just no getting around that.

My conundrum is with a open baffle, the wave cancels itself to the sides. When you pass between the speakers, the sound disappears. Then starts again as you go out the back.
I did as you said a long time ago. I had the speakers near the front wall, then started moving them out until they sounded good to me. Then I found a spot to sit. I fiddled a little with spreading them side to side and a slight turn in. They seem to play well. I have a little smear to clean. Not much.

 

[Al M.]

Not in my experience. I start with the speakers in the corners in order to maximize the room resonance modes and find the better acceptable place looking at the spectra. Surely it is an interactive process - after placing the speakers in position I do some corrections to the listening position.

However my experience relates to my room and my speakers - your experience can be different.

Text emphasized. Yes, I guess that's my point, it's an interactive process.