CEDIA Session1: High Performance Home Theater Calibration

[Audioholics]

<P><FONT face="Arial, Helvetica, sans-serif"><FONT size=2><A href="http://www.audioholics.com/techtips/roomacoustics/hometheatercalibration.php"><IMG alt="CEDIA logo" hspace=10 src="http://www.audioholics.com/images/cedia_logo.jpg" align=left border=0></A>With CEDIA’s encouragement,&nbsp;Audioholics' own Patrick Hart&nbsp;chose five classes to monitor which we thought would be of most interest to our readers. At the conclusion of these five seminars&nbsp;Patrick came out with one outstanding paradigm which was echoed by each of the presenters. That is, a signal from the airwaves or through some form of recorded media passes through all the associated wiring and electronics. It emerges from the speakers and travels through the air to your ears at your listening position. <EM><STRONG><FONT color=#cc0000>The sound of that signal at your ears is 50% the direct sound from the speakers and 50% the sound generated by the room.</FONT></STRONG> </EM>The five classes selected from the Electronic Systems Designer track were:</FONT></FONT></P>
<OL>
<LI><FONT face="Arial, Helvetica, sans-serif"><FONT size=2>“High Performance Home Theater Calibration” taught by Anthony (Tony) Grimani</FONT></FONT>
<LI><FONT face="Arial, Helvetica, sans-serif"><FONT size=2>“Room Acoustics: Acoustics Treatment” also taught by Anthony Grimani</FONT></FONT>
<LI><FONT face="Arial, Helvetica, sans-serif"><FONT size=2>“Acoustics 101” taught by John Dahl</FONT></FONT>
<LI><FONT face="Arial, Helvetica, sans-serif"><FONT size=2>“Room Acoustics: Isolation and Noise Control” taught by Steve Haas</FONT></FONT>
<LI><FONT face="Arial, Helvetica, sans-serif"><FONT size=2>“Room Acoustics: The Room and Loudspeaker System” taught by Dr. Floyd Toole</FONT></FONT></LI></OL>
<P><FONT face=Arial size=2>Take a look inside.for a thorough review of the CEDIA Session 1: High Performance Home Theater Calibration.</FONT></P>
<P><FONT face=Arial size=2>[Read More]</FONT></P>

 

[plhart]

I'm absolutely flabbergasted Hawke. We've had this great article up over a week and not one person has commented on that fact that we're saying the standard two-way, D'Apollito-style center channel speaker configuration is absolutely wrong. Does that mean that everyone understands what configurations are correct for best dispersion and vocal articulation?

 

[mtrycrafts]

I'm absolutely flabbergasted Hawke. We've had this great article up over a week and not one person has commented on that fact that we're saying the standard two-way, D'Apollito-style center channel speaker configuration is absolutely wrong. Does that mean that everyone understands what configurations are correct for best dispersion and vocal articulation?

All things take time Some longer than others

What is the better alternative if one cannot have 3 matched fronts? Difficult if one uses the space for both music and movie. While you can EQ the center to account for the screen in front, you need a different setting for music if the screen is up.

I guess all those D'Apollito speakers out there will be replaced and the speaker makers will be happy to sell new speakers

Interesting article indeed, especially with the 4 subs in the middle of each wall, not corner placed, in a rectangle room

 

[Rob Babcock]

We've had this great article up over a week and not one person has commented on that fact that we're saying the standard two-way, D'Apollito-style center channel speaker configuration is absolutely wrong.

That's not exactly a news flash, plhart. I think it's pretty well known, at least among knowledgeable enthusiasts, that D'Apollito arrays (at least horizontal ones) aren't ideal. The sad truth, though, is that they exist because many people are unwilling or unable to accomodate any other solution.

 

[Az B]

That's not exactly a news flash, plhart. I think it's pretty well known, at least among knowledgeable enthusiasts, that D'Apollito arrays (at least horizontal ones) aren't ideal. The sad truth, though, is that they exist because many people are unwilling or unable to accomodate any other solution.

I agree. Most people that have the horizontal arrays are doing it for space/convenience reasons. I've been working on a different center speaker for two years to fix this problem, but the size issue is a problem.

 

[plhart]

All things take time Some longer than others

What is the better alternative if one cannot have 3 matched fronts? Difficult if one uses the space for both music and movie. While you can EQ the center to account for the screen in front, you need a different setting for music if the screen is up.

I guess all those D'Apollito speakers out there will be replaced and the speaker makers will be happy to sell new speakers

Interesting article indeed, especially with the 4 subs in the middle of each wall, not corner placed, in a rectangle room

Thanks for humoring me, Mtrycrafts & Rob. Actually there are four solutions that I know of right now which can yield a center channel with better speech intelligibility.

1. Three-way designs with a midrange under a tweeter and flanked by woofers work great as long as that midrange is brought down low enough into the vocal range. However, most of the faux 2" and 3" size "midranges" you see are crossed over above 1KHz so they don't qualify.

2. Small mid-woofer drivers driven up to their 2.5KHz or so crossover can work well if they're pushed as closely together as possible, like many of the Atlantic Technology designs with the tweeter nestled in between the "V" formed by the two. AT also has the switchable proximity (TV) notch filter on many of their centers which makes for clear vocals without the false and unnatural "chestiness" added to voices.

3. A D'Apollito-appearing horizontal design which uses one well designed passive radiator and one true mid-woofer works very, very well. Boston Acoustics has used this trick for quite a while and I can tell you that in listening double blind the Boston would always trump the more traditional double-driven mid-woofer designs. It was that much better.

4. Same can be said for 2 1/2 way designs in which one of the two driven woofers is rolled off fairly quickly , usually at around 500 Hz, while the second woofer goes up to the ~2.5KHz crossover point. Works very well.

Re: 4 subs. Actually placing all 4 in corners works too. And there are other symmetrical locations which work almost as well. The multiple subs issue will be addressed further as we continue our CEDIA Seminar review series.

 

[mtrycrafts]

b

3. A D'Apollito-appearing horizontal design which uses one well designed passive radiator and one true mid-woofer works very, very well. Boston Acoustics has used this trick for quite a while and I can tell you that in listening double blind the Boston would always trump the more traditional double-driven mid-woofer designs. It was that much better.

Has used in the past? Not any more? Gave up on a good design or did they find anything better or just fallen for the latest and grates?





Re: 4 subs. Actually placing all 4 in corners works too. And there are other symmetrical locations which work almost as well. The multiple subs issue will be addressed further as we continue our CEDIA Seminar review series.

I was wondering about it. I can hardly wait.

 

[plhart]

b

3. A D'Apollito-appearing horizontal design which uses one well designed passive radiator and one true mid-woofer works very, very well. Boston Acoustics has used this trick for quite a while and I can tell you that in listening double blind the Boston would always trump the more traditional double-driven mid-woofer designs. It was that much better.

Has used in the past? Not any more? Gave up on a good design or did they find anything better or just fallen for the latest and grates?


Re: 4 subs. Actually placing all 4 in corners works too. And there are other symmetrical locations which work almost as well. The multiple subs issue will be addressed further as we continue our CEDIA Seminar review series.

I was wondering about it. I can hardly wait.

If you look on their site you'll see that Boston still uses the passive radiator center on some models and the equally good 2 1/2 way design which, if executed properly, has the added benefit of giving more low frequency driven piston area.

It is at this juncture that agrument of which is "better" usually comes down to how skillfully each particular design is executed vs. it's cost to build vs. it's price point and competitors vs the marketablility of the concept. It is very difficult I've found for consumers to "buy into" a concept that they can't see with their eyes. Even when it comes to buying a product intended to be listened to.



The important aspect to keep in mind with placement of subwoofers is that the studies are based on a theoretical rectangular room with no windows, doors, etc so there can be no direct real world room which will perform exactly in the manner of the program. This is a point made very clear by Dr. Toole in his CEDIA presentation.

There is an answer to this though and that is 1/12 to 1/20 band perfectly implemented parametric equalization using linear phase filters below 150Hz. It is the use of these filters which gives us the freedom to place subwoofers in areas appropriate to us who use the room rather than the areas appropriate only to the room's modal characteristics.