Yes, I do like the screen 
even though I don't use it much.
I tried to damp it using a 2" lining of denim insulation but it did not cure it fully. Finally, I just took the screen off and that confirmed the source. Because it is a long edge parallel to the line array, it creates a very strong reflection. It is fairly close to the array too.
even though I don't use it much. I tried to damp it using a 2" lining of denim insulation but it did not cure it fully. Finally, I just took the screen off and that confirmed the source. Because it is a long edge parallel to the line array, it creates a very strong reflection. It is fairly close to the array too.
Building a pair of deflector "ramps" for the sides of the screen would eliminate the reflection. Tempered 1/8" hardboard (Masonite) is cheap and takes paint well, you could even have the local big box store cut the strips for you no charge.Yes, I do like the screen
I tried to damp it using a 2" lining of denim insulation but it did not cure it fully. Finally, I just took the screen off and that confirmed the source. Because it is a long edge parallel to the line array, it creates a very strong reflection. It is fairly close to the array too.
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Yes, I do like the screen
I tried to damp it using a 2" lining of denim insulation but it did not cure it fully. Finally, I just took the screen off and that confirmed the source. Because it is a long edge parallel to the line array, it creates a very strong reflection. It is fairly close to the array too.
Maybe consider painting a "screen" onto the wall?
http://www.projectorcentral.com/paint_perfect_screen_$100.htm
ra7,
Thank you. My own stuff is moving at a glacial pace so it will be appreciated whenever you can find a bit of time.
Very interesting that your projector screen has such a strong signature. I use an acoustically transparent (ish?) screen which now has the LCR speakers behind it as well as some broadband bass traps. I can definitely hear the difference when it is off. Now I am inclined to make a measurement.
I don't use it much but it is there to stay.
Frank
Or even a short section of one, ala waveguide floor to ceiling to keep the highs off the walls. Can't remember were there horizontal mid cancellations too?
I toyed with some deflector panels. Yes, they do work! But since then another reflection got unmasked. It's coming from the non-perfect transition between the speaker edge and the wall. The cabinets are not perfectly 90 degrees, about 91-92 degrees and maybe the walls aren't flat either. After filling in the gap between the wall and cabinet with some wood strips, the new reflection goes away. So, I will be working on two things in the upcoming days.
The best looking corner wavefront appears to be where the wavefront extends right across between the wall surfaces. An OS profile could be used to stretch it outward. OTOH would it be worth trying to keep the upper mids narrow? Sounds like a challenge
Isn't it always?
It would be nice if "wings" were symmetrical, but I guess ra7 must give up to that. Curved/oblate spheroid panel in front wall side wings all the way form floor to ceiling could be possible? From plywood or even plaster board. Side walls could be "au naturel" as they are.
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Yes, naturally because the source is located inside the vertex formed with the room walls. As you have asked, I think OS would be a poor choice out to an obtuse angle because it would take the highs out with it headed for a discrete reflection per side. No, the highs are better held away from the room walls and diffracted with care in close enough proximity that the lower mids can jump off.
OS is still satisfactory for training a wavefront within an acute angle but is that even necessary in this case? OS/conical, throat angle/throat size, it can be done either way with little difference to the target mid frequencies affected by the cancellation, and hopefully with little collateral disturbance to the upper mids. Even hypex could be fitted into this role.
Mondo, if I may, picture a floor to ceiling array of full range drivers without any shading.
Next step, imagine what the floor and ceiling reflections do to the above image of the array.
Now picture that same floor to ceiling array with shading applied top and bottom.
Can you see how adding the floor and ceiling reflection of that one (with bigger movements of the cones in the centre) could be viewed as a problem?
At least in my head it works that way
The second proposal would form a wavy shaped array, again, all in my head.
Does that make sense? That's how I view the difference and why I chose not to shade my arrays. Well that, and some other reasons.
Monte Kay, who built a few CBTs, also went back to plain ol' infinite line arrays.
Hi RA7 - question for you based on some discussion from much earlier in this thread. If you were to build these directly into the wall, how would you do it? I'm building my listening room from scratch so I have the opportunity to do so. My thought is basically to use the Murphy corner array design but with the side sections built into the wall itself so the front baffle ends up ending at the surface of the drywall if that makes sense.
This will be a little more complicated as I need to coordinate with my contractor vs. just building something after he's done. But it sounds like it might be worth it to move the frequency at which directivity dips below 90 degrees. And actually, from a WAF point of view, it actually reduces the visual impact a bit. Just requires a bit of preplanning.
Would love any other thoughts you might have if you were building from scratch!
This will be a little more complicated as I need to coordinate with my contractor vs. just building something after he's done. But it sounds like it might be worth it to move the frequency at which directivity dips below 90 degrees. And actually, from a WAF point of view, it actually reduces the visual impact a bit. Just requires a bit of preplanning.
Would love any other thoughts you might have if you were building from scratch!
Yes, putting the "horn" as close to the drivers is a good idea. So, if you have the ability to build them into the walls, great, by all means do so. I would eliminate the extra edge and face in the Murphy design and go straight to the walls from as near the drivers as possible.
If you read the last few posts, you'll note that that I found an uneven gap between the edge of the cabinet and the walls causing reflections. This is happening because the wall corner and the cabinet are not exactly 90 degrees. If you can build yours into the wall and eliminate this transition between cabinet and wall, all the better. But be careful, you should be able to access the cabinet interior if you need to replace drivers, redo wiring, etc. Also, think about what would happen if you wanted to move or put the array somewhere else. Maybe you are not planning on moving, but just something to think about.
Are you going to use the same Vifa TC9 drivers? Tell us more about your build.
I haven't responded to this thread recently, but, as others suggested, I have been working on deflector panels to kill the remaining reflections. They work pretty well actually. I just made some measurements last night and there are improvements. I'll post pictures and measurements when I have something substantial.
If you read the last few posts, you'll note that that I found an uneven gap between the edge of the cabinet and the walls causing reflections. This is happening because the wall corner and the cabinet are not exactly 90 degrees. If you can build yours into the wall and eliminate this transition between cabinet and wall, all the better. But be careful, you should be able to access the cabinet interior if you need to replace drivers, redo wiring, etc. Also, think about what would happen if you wanted to move or put the array somewhere else. Maybe you are not planning on moving, but just something to think about.
Are you going to use the same Vifa TC9 drivers? Tell us more about your build.
I haven't responded to this thread recently, but, as others suggested, I have been working on deflector panels to kill the remaining reflections. They work pretty well actually. I just made some measurements last night and there are improvements. I'll post pictures and measurements when I have something substantial.