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Post by cajunbaseball on Mar 29, 2019 13:26:30 GMT
My room is dual purpose - music and home theatre. I have a 106” screen that spans almost the entire width of the 141” wide room. The screen is roughly 5 feet behind my speakers which are roughly 14 feet into the 24 foot long room. So there is a lot of space behind the speakers, but only 5 feet or so behind the screen.
What problems is my screen causing? I tried to turn the screen side ways so it would sort of divide the room in half rather than span horizontally across, but that is almost impossible logistically.
I will try moving my front corner bass traps in front of the screen when listening to music. Since the front wall is 22 feet from my ears, I figure that wall doesn’t need much treatment as I have the back wall - 24” from my ears - covered almost completely with traps.
Thanks
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Post by Hexspa on Mar 30, 2019 6:49:20 GMT
I'm sorry but I'm not able to visualize your layout. Can you post an image? From what I gather, you're sitting very near the wall behind you. This will cause more problems than your screen if it's placed behind your speakers.
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Post by rock on Mar 30, 2019 14:25:28 GMT
Yeah, the description of the layout seems unusual...to me al least. The way I imagine from your numbers is that the room width is about 12', the screen is 9' from the front wall, the speakers are 14' from the front wall and you sit 22' from the front wall or 2' from the back wall.
Why your screen is 9' from the front wall is a mystery but I'm sure there is a reason. Speakers in the rear half of the room is also unusual so out of curiosity, I'd be interested to know why. In reality, you can place your speakers and seating anywhere to hear your recordings, movies etc. but the optimum will usually be found by applying known proven principles as to positioning and treatment along with experimenting and acoustic measurement.
Basic principles learned from Ethan (I think all of this and more is in the "sticky" post at the top of the page):
Bass traps are most effective in the corners, remember, a rectangular room has 12 corners, not just 4.
Best seating position is 38% distance from front (or rear) wall.
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Post by cajunbaseball on Mar 30, 2019 15:39:57 GMT
My room is 24 1/2 feet long by just short of 12 feet wide with odd shaped walls that would be hard to describe. No matter what I do, I'm going to have acoustic issues. And in this room, I have way more than 12 corners! I'm trying to treat most of them.
I follow Jim Smith's (Get Better Sound) set up advice. I'm not trying to start any dispute/discussion about his methods v Ethan's. I respect both of them very much.
Jim puts the listening seat between 16 and 30 inches from the back wall of a room with fabulous results. Your mileage may vary. This is why my seat is 24" from the back wall in a spot where the bass is relatively flat which I determined using the RTA in AudioTools.
So, my speakers are 10 feet from my ears, which is why they are 14 feet or so into the room.
My 106" screen is 14 feet from my listening seat so I can watch movies and sports on my 4k projector. I kept the speakers in the same position as I placed them for stereo music and they sound great. Although the speakers are six or so feet in front of the screen, they disappear in the dark room when viewing anything on the screen.
That's the background. Sorry I wasn't clear before.
My question is whether the screen spanning the width of the room is causing acoustic issues and how to deal with them. I have lots of traps all over the room; most of them concentrated in the area in front of the speakers. Because the front walls are so far from the listening seat, I surmise that treating that end of the room isn't a big deal. Am I wrong?
All of my equipment is behind the screen - not between the speakers and out of view.
Homemade 18" tubes are at the first reflection points and three of four corners. The left rear corner has the entrance door to the room. I'm trying to figure some way to treat it that won't be a logistical issue.
I have panel traps at second reflection points and tubes on the ceiling reflection point. I have a couple of other tubes straddling various corners.
My thought is to move the tubes I put in the front corners in front of the screen when I listen to music. I think they will do more good there than being 22 feet from my ears. I may be wrong.
Today is "move stuff around and run tests" day. If interested, I'll report what I find.
Thanks
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Post by rock on Mar 30, 2019 16:06:26 GMT
The idea of putting bass traps in corners is that is where bass "collects" or concentrates so putting them there will be more effective. Bass traps will work anywhere but better where the nodes are. If you think they will work better in front of the screen, try it.
If your tube traps have a reflective front surface, placing them at reflection points is counter to basic principles. If they are broadband absorbers, that's OK and what you want at reflection points.
Since you're following Jim Smith's advice, you should see what he says about your situation but yeah, we're always interested to see your test results.
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Post by Hexspa on Mar 30, 2019 16:20:25 GMT
I just want to ask: how do you know your screen is causing any issue at all? Some screens are acoustically transparent, like those found in theaters that are designed for speakers to be placed behind them. I would be surprised to know that the screen manufacturer hasn't provided some information regarding this property.
My guess is that, if anything, the screen is reflective at higher frequencies. So, if your speakers are firing toward you, whatever bounces back is going to hit that screen and get reflected again. Lower frequencies may or may not radiate back and again reflect causing speaker-boundary interference. However, if this is happening, whatever band of sound that the screen reflects is also being prevented from hitting you again once it's behind the screen. In that sense, this is potentially a double-edged sword.
In any case, you can take measurements and see whether the SPL response changes based on whether the screen is up or down. Since your screen is 14' away and your rear wall is 2' from the back wall, you could also play impulses through your speakers and listen for echo at your listening position - or just clap.
Ultimately, unless we know what the screen material is, there's no way to know exactly what acoustic properties it has. Have you tried breathing through it? As silly as it sounds, that's kind of the litmus test for whether a fabric is acoustically transparent.
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Post by cajunbaseball on Mar 30, 2019 22:49:45 GMT
Thanks. Added some traps and moved some. Still tweaking. Sounding better!
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Post by cajunbaseball on Apr 5, 2019 13:01:31 GMT
Thanks. Added some traps and moved some. Still tweaking. Sounding better! I want to test my large front speakers with my Debra/Swarm 4 subwoofers. REW allows LR speaker, but not speakwrs + subs. Windows sound panel gives options for “Front Speakers,” “5.1,” “7.1”etc. I run the mains with the my Ayre amp through a preamp and the subs connected to the pre via RCA two to each of two separate amps. So for music, it’s 2.2. REW is on a laptop connected to my Marantz processor via HDMI. How do I configure Windows and/or REW to play the mains and subs together? Thank |
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Post by Hexspa on Apr 6, 2019 13:29:17 GMT
My main speakers a routed through my sub. You could always send the signal into a mixer and split it off. Alternatively, you could try using something like VoiceMeeter Banana to send the software output from REW into different hardware outputs.
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