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Room treatment to fix issues and add depth


No.4

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37 minutes ago, ClaudeJ1 said:

Around 2012, [Artto] then invested in 3 SH-50s, thinking he needed a center.  After a complete change in layout, he sold me his center unit because it was simply NOT needed with Synergy horns R & L. His 3D imaging is second to none in that room IMHO.

Artto's old listening room with Khorns and a Belle is an example of one needing diffusion--which he added in "massive terms":

 

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His new room using Danley SH-50s (the "50" indicates the designed horizontal coverage angle of the loudspeakers which is narrow for home loudspeakers) first came in a "wide version":

 

07c4adb7_Danley1_now.jpeg

 

Then a narrow version, for which he (apparently) opted to retain, and to drop the center SH-50:

 

b770b3d0_MusicRoomSH50_shortwall_2.jpeg

 

 

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DSC01239OSB_WholeWall_25%.jpg

 

 

Chris

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Note that the R and L are now out of the corners completely. Danley's published curves are from outdoor measurements. Even though the specs show bass down to only 50 Hz., they actually go down to 40 in a real room, which is where my subs are crossed. Artto had 4 subwoofer cabinets, two under, as shown and two in the rear of the room, each with twin 15" drivers for a total of 8. Being a bass player, he definitely has a lotta bass down to 16 Hz. which is impressive also.

 

In my room, the SH-50's actually have a bit too much bass, so need to be attenuated by the room EQ. Hard to believe from a horn this small, but it works, as Chris knows from building his MEH horn!

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4 hours ago, Chris A said:

I find that most all "audiophiles" tend to focus on the subjects that they're aware of and which they have easy answers to (focusing entirely on electronics, sharp pointed feet on loudspeakers, and "equipment synergy" ideas), but to the total neglect of doing something about the other elephants in the room--that they choose to ignore.  Early reflections happens to be one of those elephants, I've found.

 

Chris

I think we are all guilty of that to some extent at one point or another in the audio journey. The visual appeal of of countless audio products probably far outweighs the sonic qualities. As upgrades to components go I have swapped out resistors in the signal path, capacitors, different types of tubes etc. while they do change the sound it can be difficult to determine if the change had added something or taken something away. In all of these situations the changes have been very subtle and probably only perceptible to me being very familiar with how my setup sounds. My experimenting with room treatment has yielded much different results so far, and I am only in the early stages. 

I ordered some roxul rockboard 80 and began to place a few of the panels in the obvious areas that would contribute to "early reflections". I did a measurement for every panel move around the room. I am away from them right now but I will post them later. The addition of every panel improved the excessive group delay readings throughout the spectrum. After about twenty measurements I decided to just listen to some music. 

The "improvement" is immeadiate and obvious. Any listener would perceive the difference. I usually keep my pre set at one volume. This has been this way for a few years. For lack of a better term it is my reference volume. Everything seemed balanced, it was perfect. With the panels I have in place I cannot help but raise the volume well beyond this point. The soundstage has a whole new focus and depth. The separation of voices and instruments is amazing. This is simply put a new system. I won't go on and on with audiophile jargon, but treating the room is by far the most important change I have made, maybe even more important than adding a sub. Please don't spend any more money until you build some panels and see for yourself. 

IMG_0208.JPG

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I finally got around to finishing the first round of panels and was able to take some measurements. The change in the sound is amazing, but I am sure @Chris A will tell me I have a long way to go;) I need to decide how I am going to treat the rest of the room, or rather where I need to treat it. I am also trying to figure out where to add bass traps, and what the optimal height of the subs mouth needs to be. Since the sub fires at the ceiling I think I need to get it a little closer to it. I am thinking the distance needs to be around the length as the width of the mouth. This will most likely require some more trial, error and measurement. below are the measurements from the first round of finished panels compared to the original untreated room. 

left untreated.jpg

left no sub treated 1 group delay.jpg

right untreated.jpg

right no sub treated 1group delay.jpg

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Good job, when you are satisfied with the sound the only thing left to do will be to make these things look more pretty :)

 

I am certainly no expert here but several of my friends that make DIY speakers found it easier to fix bas back reflections (and I believe some mid-frequencies too) in the boxes by applying acoustic wool. I know this is entirely different type of construction and more easy to make (usually simple compression boxes). That is what make these speakers more appealing to DIY-ers. It is cheap and easy to make. Of course acoustic treatment will still be needed if aiming at maximum what the speakers can deliver, but at least it solves one part of the problem.

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15 hours ago, Chris A said:

Recommend using psychoacoustic smoothing on your measurement plots.

Ok, I have applied that to the measurements and the appearance of the plots is definitely different. What is the benefit or reason for using psy smoothing?

6 hours ago, parlophone1 said:

Good job, when you are satisfied with the sound the only thing left to do will be to make these things look more pretty :)

 

Thank you. I was actually pretty quick to cover the panels. I didn't want the addition of the panels to catch too much negative visual attention.

IMG_0231.JPG

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1 minute ago, No.4 said:

...the appearance of the plots is definitely different. What is the benefit or reason for using psy smoothing?

The short story is...that's the way that the human hearing system perceives sound: think of the functioning of the cochlea and the individual sensory hairs within it--and how they're wired to the brain and its processing. 

 

Another way of saying it is that the human hearing system doesn't hear using 1/48th octave resolution.  If you try to correct the sound reproduction system based on higher resolution data (or even just view it to understand what is occurring), you'll wind up with higher levels of processing or analog filter noise--not perceptionally better sound. You'll also find yourself chasing artifacts that aren't relevant to what your ears hear.

 

Now--there are times when seeing the 1/48th octave resolution data can bring insights into what is causing certain anomalies in loudspeaker performance, etc., but when correcting the frequency response, phase, group delay, etc., psychoacoustic smoothing most closely matches what we perceive. 

 

Of course, like most things in life, the actual story is even more complicated, but the basic truth of the explanation above doesn't change.

 

Chris

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1 hour ago, No.4 said:

Ok, I have applied that to the measurements and the appearance of the plots is definitely different. What is the benefit or reason for using psy smoothing?

Thank you. I was actually pretty quick to cover the panels. I didn't want the addition of the panels to catch too much negative visual attention.

IMG_0231.JPG

These look really nice. Primary reflection points are the most important piece of room treatment in my opinion. When I firsts set up my LaScalas in our new house with no treatment I could barely listen to them. I hung some curtains with tacks at the primary reflection points and now all I hear is sonic bliss for a 15 min of work and know-how.

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3 hours ago, twk123 said:

When I first set up my La Scalas in our new house with no treatment I could barely listen to them. I hung some curtains with tacks at the primary reflection points and now all I hear is sonic bliss for a 15 min of work and know-how.

 

Actually...I still recommend a calibrated microphone to do acoustic measurements in room...about $50-100(US), which is very cheap compared to most anything in this pastime/hobby.  The software is free. 

 

This is a dramatic change in the economics of doing acoustic measurement in my experience: stuff that I only dreamed of doing only a few years ago is here, and affordable.   These are very powerful measurement capabilities available basically for free that really help to understand what's really going on and how much of what type of treatment, loudspeaker/listening position placement, and the effects that nearby furnishings have on resulting sound quality. 

 

Using your ears combined with measurement is the real enabler.  I've learned the hard way that estimating things like reverberation time (e.g., RT60) from using only my ears isn't very useful to know what you're dealing with.  Also understanding the effects of reflections immediately around the loudspeakers including side walls and front wall, plus any acoustically reflective objects in the near field, is generally required to understand what you're dealing with.  These are probably the biggest factors in the resulting sound that you get in room.

 

Chris

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18 minutes ago, Chris A said:

 

Actually...I still recommend a calibrated microphone to do acoustic measurements in room...about $50-100(US), which is very cheap compared to most anything in this pastime/hobby.  The software is free. 

 

This is a dramatic change in the economics of doing acoustic measurement in my experience: stuff that I only dreamed of doing only a few years ago is here, and affordable.   These are very powerful measurement capabilities available basically for free that really help to understand what's really going on and how much of what type of treatment, loudspeaker/listening position placement, and the effects that nearby furnishings have on resulting sound quality. 

 

Using your ears combined with measurement is the real enabler.  I've learned the hard way that estimating things like reverberation time (e.g., RT60) from using only my ears isn't very useful to know what you're dealing with.  Also understanding the effects of reflections immediately around the loudspeakers including side walls and front wall, plus any acoustically reflective objects in the near field, is generally required to understand what you're dealing with.  These are probably the biggest factors in the resulting sound that you get in room.

 

Chris

I see what you are saying and I currently probably only have my room up to 60%-70% its full potential. Microphone measurements and software assistance for further treatment will definitely bring that number closer to 90%. That being said, for someone just getting into room treatments I recommend this as a starting point as it makes a dramatic difference and is easy to set up with a mirror and dollar store laser pointer. It is also all that some people with speakers in living rooms etc to get away with due to WAF.

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25 minutes ago, twk123 said:

I see what you are saying and I currently probably only have my room up to 60%-70% its full potential.

Perhaps not that high...which is my point...

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4 pages of replies & I can't believe no one has said anything about the big mirror above the audio rack. take it down & have a listen, I guarantee your perception of vocals will change. while you're at it remove the two glass top tables on the wall with the window. any glass surface in the room will cause havoc with reflections. also try an experiment with 1 panel (diffuser/absorbition combo) behind the audio rack. my room is similar to yours & that panel really made an improvement in depth of soundstage & vocals seem to fill the wall all the way up to the ceiling.  hanging a heavy blanket to block the window while listening to music will also help big time 

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28 minutes ago, edmjm said:

4 pages of replies & I can't believe no one has said anything about the big mirror above the audio rack. take it down & have a listen, I guarantee your perception of vocals will change. while you're at it remove the two glass top tables on the wall with the window. any glass surface in the room will cause havoc with reflections. also try an experiment with 1 panel (diffuser/absorbition combo) behind the audio rack. my room is similar to yours & that panel really made an improvement in depth of soundstage & vocals seem to fill the wall all the way up to the ceiling.  hanging a heavy blanket to block the window while listening to music will also help big time 

I do plan on removing the mirror and doing some measuring, however in the spirit of compromise it will be going back up. I am looking at some other materials that are hopefully lighter weight that I may be able to make a screen or cover for the mirrror that I can easily put up and remove. The window is obviously an element (my phone tried to change element to enemy) that I cannot remove from the room so I can only cover it. I will do the same for it. I did place some rockboard over the window during a few measurements and it actually did very little to the 5k to 20k range. I may also rework the panels with two layers of different density material in hopes that it will absorb more of a broad band of frequency. 

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I know exactly what you mean by compromise, my listening room is supposed to be the dining room with no back wall, just open into the family room. the mirror is easy enough to take down when listening put back up when done. measurements are a good starting point but like a few others said earlier trust how you like the sound. sit & listen to one of your reference songs with the window exposed then again covered. the sound bounces off drywall on one side at a different speed than off glass (forgive my non-expert simple description) making the first reflections hit your ears at different times causing an imbalance from the listening position.

careful adding extra layers cause it could "deaden" the room. I love how panels in the first reflection position make the soundstage so much wider

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  • 4 weeks later...

I have not forgotten this thread, I have just been busy. I have however made a little progress here and there. Each step improves the sound to some degree. Some changes are more noticeable than others. The attached pics show the starting point with bare walls and where I am now. I really want to get control of the higher frequencies, however those changes have come in very tiny increments. I did cover the mirror and it does make some definite improvement in the depth of the sound. I may also add some diffusion in between some of the panels on the front wall, I just need to learn more about them and how to implement them. Diffusion does not appear to be as straight forward a topic as absorption.

L treated front, floor, back wall.jpg

L no sub original bare wall baseline 1M.jpg

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@Chris A Any advice on how to address the decay time or reflections in the higher frequencies? For the most part the frequencies below 5k are really accurate and sound amazing, but I feel like above 5k there is still a little of the "head in a vice" sensation occurring. I really want to turn up the volume because the lower frequencies sound so clear but it really causes the highs to sound harsh at times. Either way, the improvement versus investment cannot be beat.

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High frequencies are the easiest to absorb.  I would encourage adding more absorption on top of and around the midrange horn and listen again. 

 

The "head in a vise" could be beaming and that's a function of the tweeter itself and its horn.  I'd move your microphone up to be on centerline with the tweeter axis and check to see if the frequency response is still flat or if it's rising in response.  You can also take measurements off axis laterally to see how much the tweeter response falls off with off-angle.  Then you can see if it is beaming or something else. 

 

EDIT: If it is beaming, then there is one thing that you can do to reduce the on-axis SPL--put some cloth material directly on centerline but spaced in front of the tweeter horn about at the plane of the midrange horn mouth and about 2"-3" diameter--like a microphone blast filter, only using more acoustically absorbent material.  While this will tend to attenuate tweeter frequencies relative to the midrange driver/horn, I assume that you can readjust the balance to bring it back to about the same level as the midrange.  It's not a solution, but it's a fix that will work.

 

46c2517b8582c097e40f2dd44138c9e3.jpg

 

Chris

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I took several SPL measurements today. I'm not sure if I took the off axis lateral measurement correctly, hopefully @Chris A will shed a little light on that. Aside from more and more absorption around the tweeter horn, would L pads be an option to attenuate the highs a little, or would that introduce a dip around the 4500hz zone?

 

 

goldenrod is with 1 1/2" denim padding on top of the mid horn below the mouth of the tweeter.

green is with 1 1/2" denim plus a 1" dense denim panel that covers the bottom 25% of the tweeter horn.

purple is with the above combination with the mic 1M from the tweeter turned 90%

Blue is the baseline with the mic 1M from the bass horn dead center.

5992175d41c58_responsecharts1Mtweeter.jpg.62c314b8a1670a625000f0c25d876e6b.jpg

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