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Room Treatment for Line Arrays
Room Treatment for Line Arrays
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Old 24th April 2019, 03:55 PM   #21
Nvphotos is offline Nvphotos
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This is a photo of that half wall.
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Old 24th April 2019, 04:04 PM   #22
mushroommunk is offline mushroommunk  United States
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Let's see, 2.5ms is what, .75 meters? So probably a good bet on the wall causing the reflection. Can you pull the couch forward even a few inches? Then you could place an acoustic panel right behind your head. Can even wrap it in fabric to make it look pretty for the spouse if that's necessary.
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Old 24th April 2019, 06:17 PM   #23
Nvphotos is offline Nvphotos
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I was thinking of doing that. Two questions:

How effective are pillows?
What frequency ranges do I need to target in this location?
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Old 24th April 2019, 06:24 PM   #24
mushroommunk is offline mushroommunk  United States
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1) How effective are pillows.
A) Extremely effective, or not effective at all, or somewhere in between. Really depends on the pillow, it's stuffing, how thick it is, etc. I'd err on the side of "better than nothing but can be beat easily".

2) What frequency ranges do I need to target in this location?
A) Ideally all of them. If you don't absorb everything you're essentially just EQ'ing the reflection. In practicality "as much as you can" is usually the result.

Not helpful answers I know, but sometimes it's like that.
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Old 28th April 2019, 03:02 AM   #25
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Whether it is effective or not, I took my wife to the store and bought 11 couch pillows for two rooms. I can still make panels in the future but at least for now my wife is happy

... and yes, they were a steal of a price at $2 each.
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Old 28th April 2019, 10:32 AM   #26
wesayso is online now wesayso  Netherlands
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You can put the arrays pretty close to the corner, but it would need a damping panel beside the array to keep it sounding clear.

Don't judge any sound you get if it isn't EQ-ed for that spot. The closer the array is to the corner, the easier it will make bass. However if the left and right array are placed identical/symmetrical in their respective corner, chances are you're going to get dips that align on both sides. I have two different corners which is why I can shuffle some energy between the arrays below 70 HZ to get an even response at the listening position.

To make the corner position work in the midrange I just concentrated on the IR. I EQ-ed the response as flat as I could (not for listening purposes) and viewed the different peaks found in the IR. Next I took some damping material and placed it at different spots in the room to see if I could reduce those peaks. Those were the spots that needed damping panels.
Once you get the peaks in the IR down far enough, the clarity will come back in spades. At least, if you apply EQ with a decent room curve.

That half wall sure is a likely suspect for early reflections. I have a full wall behind my couch, I hung a damping panel/poster there and fill the space between the couch and the panel/poster with fluffy pillows. Luckily with a woman in the house there's always plenty of those around.

The side wall damping panel should be just clear of the wall by an inch or so. Make it 3 inches in thickness and it will clear the reflection off of the side wall. I have it beside the array, sticking out in front of the array by about half a meter. Measurements showed me it was very effective. The IR cleaned up immensely.

Only after FIR correction I examined the sound. Crude EQ will never tell you if it is boomy etc. We haven't seen a clear frequency curve yet that lets you judge the sound.

My corner placement was deliberate, as, like you I wanted the arrays to cover the bottom end. Just remember that a slight difference in exact placement for left and right may let you balance out that bottom end.

I've ran this setup with a 100 watt into 8 ohm amplifier without problems. Most of my graphs were made with that combo. I've come across a few problematic songs that showed me the limits of this kind of power.
Most notably: "A Perfect Circle" with the song: "Lullaby". With clever balancing between both arrays in bass frequencies I managed to play that song without breaking stuff. It has a pumping low end that will be felt more than heard. It is a pretty tough workout. I listen at ~86 dB on average (according to my Radioshack SPL meter) and never broke anything yet.

So don't sweat the amplifier power. First try to clean up a measured IR, but do apply some pré EQ to get it reasonably flat, to get the IR to show the right things. An IR is a rendering of the data and highlights high frequencies more than others, all other graphs can show us that exact same data in other ways. Once you clean up the IR, all plots will start to look more presentable. However with arrays, not without the proper EQ.

Again: try and get a readable scale on the plots, it makes it easier to analyze. Look at the plots Mitch showed, get the numbers on your plots to align.
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Old 28th April 2019, 11:30 AM   #27
wesayso is online now wesayso  Netherlands
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Another piece of advice: don't rush it. Learn what the graphs tell you. Take the time to be able to make sense of what you see. As said, the IR is the same data you see in all other graphs that are derived from it, just presented differently. Understanding how they all relate to each other can tell you a great deal of what it is you hear.

The MiniDSP isn't going to be a short cut save all solution. Fix what you can in the room, it will be far more effective.
After that the DSP can give you the balance for pleasing sound, good tonality and great imaging. You can't really fix a room with DSP. You can control tonality and balance after first making sure the first room reflections are diminished enough. That can either be trough clever speaker placement or treatment with damping panels and/or diffusion.
If the side walls are close to the speakers (in order to get bass), absorbing works best. If there is some distance between either the speaker or the listener and the reflective object or wall than diffusion could become a viable option to go for.

The beauty of these arrays is that you don't even have to have much treatment in order to make a huge difference.
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Last edited by wesayso; 28th April 2019 at 11:34 AM.
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Old 28th April 2019, 11:46 AM   #28
wesayso is online now wesayso  Netherlands
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Maybe this will help you to "see" what can be done:
Room treatment - Full Range Line Array / REW measurement

And:
Room treatment - Full Range Line Array / REW measurement
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