Importance of horizontal dispersion IN MY HOME listening environment....

[malboro2]

I'm planning on building a plane array in a 4 way design. There will be four tweeters configured in a square so that CTC is less than .84 inches. There will be four 3.5 inch mids configured in a square so that the ctc will be 4.5 inches. It also has one(maybe 2) 8 inch woofers, and 1 12 inch sub woofer(in each channel). Comb filter distortion stays under one wavelength due to the closeness of the CTC and the crossover frequencies.

I have been told that the midrange horizontal disperson will be cut in half and for that reason I should not put them together like this. However my listening area is about 13 feet from the speakers in a sweet spot of 4 feet horizontal(couch). My online dispersion calculator says that the horizontal dispersion of the speakers individually is 38 feet at 13 feet listening. So cutting that in half is 19 feet. Even if I don't angle the speakers, it would seem that for me, in my listening environment, horizontal dispersion is a non-issue. The same exists for vertical since I am listening to the mids and tweets at ear level. I simply don't care about precision in other listening places or heights.

While for another environment this could easily be a problem, I don't see it as one for me in my listening environment.

Am I missing something important here?

[mzisserson]

You seem ro have answered your own question. There are other issues with clustering drivers aside from comb filtering and calculable dispersion issues, but if the advantages outweigh any of the bad, then build it. There's no perfect speaker, only a combo of strengths and weaknesses we are willing to balance.

[malboro2]

You seem ro have answered your own question. There are other issues with clustering drivers aside from comb filtering and calculable dispersion issues, but if the advantages outweigh any of the bad, then build it. There's no perfect speaker, only a combo of strengths and weaknesses we are willing to balance.

I was kind of hoping that was the case. I know enough about this stuff to think I know more than I actually do. Most designs like this are made to operate in stadiums and churches, and so finding valid information is hard, and finding information on nearfield listening in Plane(as opposed to line) arrays is nearly impossible. Griffin didn't write about this one.

13 years ago many more people actually were building and listening to real speakers. Now everyone thinks hifi is an earbud on an iphone. It sad.

[dynamo]

This brings a question I always wonder.. if reflections and room influence are always variables and potential issues, why don't we design horizontally controlled speakers? What are the downsides? I'm suspecting soundstage/imaging reduction but am really curious on this.

[marvin]

Isn't that what horns are for? Dr. Hsu uses horns and deliberately toes them in quite sharply to help reduce room interactions.

http://www.hsuresearch.com/products/ccb-8.html

[fpitas]

I toe my horns in to point at my ears. The soundstage and imaging are quite good. And on the OP's subject (sort of), I used two 6.5" mid-bass drivers side-by-side to match the horn horizontal directivity (90 degrees) at the 750Hz crossover.

[mzisserson]

I was kind of hoping that was the case. I know enough about this stuff to think I know more than I actually do. Most designs like this are made to operate in stadiums and churches, and so finding valid information is hard, and finding information on nearfield listening in Plane(as opposed to line) arrays is nearly impossible. Griffin didn't write about this one.

13 years ago many more people actually were building and listening to real speakers. Now everyone thinks hifi is an earbud on an iphone. It sad.

It is very sad..... Not to mention recording has gone the way of optimizing fidelity for i-pads and earbuds.


Remember: A home environment is radically different from a large venue. The time things have to sum, as well as early reflections are extremely important.

The more you know in this hobby, the less you realize you actually know. So build, and enjoy the expirence!

[dynamo]

True with the horns, I guess I was thinking more like the OP was suggesting and fpitas shows with side by side mids and / or tweeters. You don't see it much commercially. Only thing that comes to mind is some legacy and mabye mac stuff. It just seems like it makes sense (in my untrained mind) to help further the room from being a problem.

[filmslayer]

maybe i'm missing something here , but here is my Prototype CC and measurements at 0* , 15* and 30* ...

[malboro2]

If dispersion in an issue why not slightly tilt the speakers, which are four placed together, so that they are slightly tilted away from the center of the square. The tilt would be slightly up and out for the upper two, and slightly out for the lower two.

[dynamo]

maybe i'm missing something here , but here is my Prototype CC and measurements at 0* , 15* and 30* ...

I'd be curious to see beyond 45 degrees

[filmslayer]

I'd be curious to see beyond 45 degrees

i didn't do a 45* horizontal , the reason being a center it would put you rite in front of the L/R mains as this was built for my space ... i did do 45* vert.

[ryanbouma]

I've used side by side mids in all of the diysoundgroup Cinema speakers. It started with the Elusive 1099. It was very very challenging and that was with a waveguide tweeter. I caution you doing this. Sent from my SGH-I337M using Tapatalk

[Sydney]

... side by side mids and / or tweeters. You don't see it much commercially.....

It is done in Live Sound provided that the dispersion characteristics are consistent through out the passband.
( Bob McCarthy details the Mathematics in his seminars and books ). The key is to match the -6db down points in the pattern to sum even.

[ryanbouma]

maybe i'm missing something here , but here is my Prototype CC and measurements at 0* , 15* and 30* ...

Are you sure that's an actual 30 degrees? The tweeter top end doesn't look it. Also, whether or not nulls appear depends on the XO points and how steep the crossover slopes are. Sent from my SGH-I337M using Tapatalk