weird phasing issue or something

[Paducah Home Theater]

So, weird and longstanding issue.  First of all my room is non-traditional because my wife wanted four seats in a row so the whole family can be together, so the screen is on the long wall, meaning our seats are fairly close to the back wall, like 4'.  Then I used RS-62ii's as the rear surrounds.  Should have used bookshelves but I think they look funny bolted up against the wall to be honest.  Height has the top at 6' which isn't really out of the norm for non-Atmos setups.  When sound is flying around the room it tends to be ok.  

 

Weird thing is though, when you're on one side of the room, you can only hear the opposite speaker if both of them are going.  So if you're sitting on the left and both rear surrounds are going, you can only hear the right one.  It's like the one right behind you is AWOL, it doesn't exist.  I've checked polarity, everything is fine.  Checked individual speaker output, it's fine.  Even had one of the nations top calibrators over and he set everything by hand, it's not a calibration issue.  

 

Thought it was a reflection issue for a very long time but I've been playing with quite a bit of acoustic insulation in my room and it sounds exactly the same no matter what I do.  I'm assuming its a phase issue where on is being cancelled out, or something related to the angles of the tweeters.   Other than rotating my room 90 degrees so there's more space behind us, or switching to direct firing towers or in-walls, possibly even lowering the in-walls as to be more consistent for an Atmos setup, I'm not sure what to do, but I guess it's come to that.  Most likely will squeeze in some more acoustic panels on this back wall and try something else for the rear surrounds.  Any other ideas?  

 

Edited December 19, 2015 by MetropolisLakeOutfitters

[minermark]

"Thought it was a reflection issue"

I do not do HT, i have however assisted a few bud's with design and running wire.

 

In your pic im looking at two rear speakers.

Take both speakers and "Rotate" both 3" or so, like turn them on the wall, twist if you will.

Run you're walk throught test, see/hear any difference Turning those made.

 

Just my two cents, you need to start somewhere, height, direction, reflection, dampning?

Twist them, costs nothing, min hassel/damage to wall.

[Chris A]

Lower them to be about a foot above your head while seated.  Try listening again.

 

You could also tilt them toward the floor about 30-40 degrees if you don't move them down. 

 

The issue is apparently coverage of the HF horns.

 

Chris

[Quiet_Hollow]

Those are bi-poles.

 

They only work as designed when mounted to the immediate flanks of the listening position (90 degrees).

 

They sound like one is disappearing (as you have them mounted) because they in-fact do not radiate any sound along their plane of symmetry.

Edited December 19, 2015 by Quiet_Hollow

[Chris A]

There may be a null on axis separating the two hemispherical coverage areas, but actually a bi-pole is supposed to have uniform coverage over something like 180 degrees azimuth. 

 

So it may be a neutral axis issue.  It's easy to detect: just walk by the loudspeaker while it's playing, and listen for any changes in its loudness as a function of azimuth.

[derrickdj1]

I think the issues is not phasing and basically the location.  Tom is correct.  That is why The speakers need to be spead out.  I would just convert them to a 6.1 system.  Have the speakers next to each other or just use one.

[Chris A]

I believe you're confusing di-pole with bi-pole.  Bi-poles have 180 degrees of coverage.  That's the major difference.

[Paducah Home Theater]

Strange, if that's the case. Never would have guessed they'd behave that way. I'd feel stupid but that high end thx room that Klipsch has shown off or years has the same exact situation going on. My room is very similar to this layout, just reference instead of thx.

Edited December 19, 2015 by MetropolisLakeOutfitters

[minermark]

Strange, if that's the case. Never would have guessed they'd behave that way. I'd feel stupid but that high end thx room that Klipsch has shown off or years has the same exact situation going on. My room is very similar to this layout, just reference instead of thx.

Twist/turn/rotate them in place, come on play, dammit man, im in the mood for a milestone here.

[Quiet_Hollow]

At this point, I highly recommend the use of an SPL meter and pink noise to investigate your sound field and listening positions if you feel you have a problem.

[Paducah Home Theater]

Those are bi-poles.

I believe you're confusing di-pole with bi-pole.

 

Not sure it's quite that simple.

http://hometheaterhifi.com/reviews/speaker/surround-sound-speaker-systems-reviews/klipsch-51-reference-ii-speaker-system-for-the-home-theater/

"I originally wrote that the RS-62 II surround speakers were bipole designs with a tweeter and a mid/bass driver mounted on each side of the cabinet. This is what Klipsch said when I sent in the review for fact checking, “actually we call it Wide Dispersion Surround Technology (WDST) with the dual horns creating ambience closer to the wide ambience created by dipole speakers, yet with ambience all around the listening area instead of in just a small “null” area where dipoles create their best ambience. The WDST technology also reproduces direct sounds very faithfully, which both bipole and especially dipole speakers have trouble with (they produce these sounds usually with too much ambience). Finally, the WDST design of our surrounds makes them very placement flexible in a room, whereas, with dipole speakers especially, they need to be carefully placed for their best effects.”"

from a spec sheet: "Klipsch Wide Dispersion Surround Technology (WDST™), which enables it to deliver a unique combination of diffusion and coverage, yielding the benefits of both diffuse- and direct radiating surround speakers with the drawbacks of neither. Listeners enjoy the deep, enveloping surround sound field characteristic of diffuse-radiating designs together with the precise localization of specific effects typically provided only by direct-radiating models."

I'm not real sure what it's doing, they claim its neither bipole nor dipole. I agree that direct sounds are excellent.

Edited December 20, 2015 by MetropolisLakeOutfitters

[Chris A]

Have you tried moving them down or tilted forward yet?

 

I believe that Tom's suggestion on using an SPL meter will work pretty well for finding out the azimuth polars of this loudspeaker. Everything else that Klipsch has said above looks like the kind of stuff that PWK himself would flash his yellow lapel button after it was said.  Walking around the speakers while they are playing and recording the SPL meter average readings as a function of listening azimuth is really the most direct way of finding ground truth. 

 

I don't understand why they wouldn't just publish the azimuth and elevation polars for this loudspeaker, like the Cinema line publishes for its loudspeakers.

 

Chris

Edited December 20, 2015 by Chris A

[Paducah Home Theater]

Have you tried moving them down or tilted forward yet?

No I've been building acoustic panels and painting all weekend. Will try this soon.

[Paducah Home Theater]

As a follow-up, I ended up just taking them out completely. Took them out to play around and experiment but it sounded so much better that I just replaced them with acoustic panels. Movies that I was used to suddenly had more defined surround sound that panned between the mains and rears way better. Somehow the sides and rears were cancelling each other out on quite a bit of material. Playing each one individually was fine but when multiples were playing together, weird stuff happened. Just not worth messing with, I like the way it is now, two of these on the sides sounds good. May try some direct firing bookshelves behind me in the future.

Edited January 8, 2016 by MetropolisLakeOutfitters