I'm getting close to having my system dialed in, which brings me to the final frontier: tuning my room.
my listening room is in a smallish, 1500 sf condo and comprises my kitchen, living room and dining area. The room itself is about 16" x 24", the seating area where my system and sofa are is about 12w x 10" deep, with the dining area directly behind it and the kitchen to the left, as well as the main entry. I don't hear any prominent echoes when I clap my hands or snap my fingers, but the spectrogram tells a different story.
further complicating matters, the blank space above the credenza is a projector screen, so it can't be easily treated and the wall to the right is irregular and approximately 60-70% windows, with sheer curtains and blackout shades. how may I best treat my room to reduce reflections? my speakers, which resemble Klipsch LaScala, have passive radiators mounted on the back of the upper horn enclosures, extending the bass to 23Hz- intuitively, I'm thinking bass traps and diffusers behind and above the speakers and heavy rugs in front of the speakers; am I on the right track?
would mounting diffusers in the RH corner and above the L speaker, such as the one below, help?
I could also install bass traps directly behind the speakers. Unfortunately, we rent, so treating the ceiling is not an option and WAF is also a consideration, as are budgetary constraints. That being said, what are the best bang for the buck options, assuming I have more than adequate woodworking skills (I'm a master carpenter and former cabinetmaker; I engineered and constructed my speakers and make my own furniture).
my listening room is in a smallish, 1500 sf condo and comprises my kitchen, living room and dining area. The room itself is about 16" x 24", the seating area where my system and sofa are is about 12w x 10" deep, with the dining area directly behind it and the kitchen to the left, as well as the main entry. I don't hear any prominent echoes when I clap my hands or snap my fingers, but the spectrogram tells a different story.
further complicating matters, the blank space above the credenza is a projector screen, so it can't be easily treated and the wall to the right is irregular and approximately 60-70% windows, with sheer curtains and blackout shades. how may I best treat my room to reduce reflections? my speakers, which resemble Klipsch LaScala, have passive radiators mounted on the back of the upper horn enclosures, extending the bass to 23Hz- intuitively, I'm thinking bass traps and diffusers behind and above the speakers and heavy rugs in front of the speakers; am I on the right track?
would mounting diffusers in the RH corner and above the L speaker, such as the one below, help?
I could also install bass traps directly behind the speakers. Unfortunately, we rent, so treating the ceiling is not an option and WAF is also a consideration, as are budgetary constraints. That being said, what are the best bang for the buck options, assuming I have more than adequate woodworking skills (I'm a master carpenter and former cabinetmaker; I engineered and constructed my speakers and make my own furniture).
I am also about to embark some room tuning......I think phase cancellation is occurring due to sound being reflected of the wall facing the speakers. I was going to treat the ceiling and walls with some kind of diffuser.......are there any commonly available construction materials that could be used?
As stated in posts above, look for the first reflection points. To absorb them is easiest and least expensive, to scatter them as with your wood diffuser is what sounds best to me. Because you are using horns all the way up, the walls want be hit as much as with direct radiators. But they will still be hit and you'll hear it.
Tuning the room should be the FIRST thing you do! But better now than never - you are one step further as many enthusiasts
Before even THINKING about diffusion you need to add A LOT of absorption first. Your room is only reflection and diffusion now - it needs a lot of dampening to get that out of balance and too much.
When thinking about absorption - play around with this calculator: http://www.acousticmodelling.com/porous.php
You need DEEP absorbers with light, fluffy material to get low frequency absorption. And you need a serious amount of surface (10-20% as thumb rule) to really make a difference. 20% of the room surface ... is a lot!
Also use this calculator to estimate the efficiency of rugs and curtains ... these make a room dull (absorption >3-5kHz) but not controlled (absorption >100Hz).
What to do:
Use unused corners and fill them as much with fluffy material as you can. There are more corners as the 4 from your wall ... you can use the space behind your couch, on top of cabinets and so on.
Check your first reflection points and get some nice looking panels there. The most important is often the ceiling, it widens the image vertically unnaturally. Reflection points at the side can make a broader image, but also a "smeared" image. Some prefer that.
In a REAL listening room you would think about a concept you like and then realise it through the whole room. But in living spaces it needs to do compromises.
These are professional variants of listening rooms - worth a read, also when it's not 100% possible to achive that. https://www.soundonsound.com/techniques/sos-guide-control-room-design
I'm a little surprised that no one has mentioned that your REW measurements will tell you a lot already (and I apologize for just finding this thread).
Some candidates are below:
The "RT60" plot will tell you about the relative amount of absorption in-room that's effective. The plot above is from my listening room with the microphone one metre in front of the right Jubilee and centered on the K-402 centerline. Notice the relatively flat Topt and RT30 curves (the green and yellow-orange traces). These tell you if the total amount of absorption in-room is about right, or, as is more likely the case, you need to add a bit more.
For your listening room of about 3000 cubic feet (assuming your ceiling is 8 feet), an average RT value in the 300-10000 Hz range will likely be ~0.3 s to 0.4 s. The flatter these RT curves are, the better.
If there is insufficient absorption in-room, usually there will be a significant rise in RT values around 1-2 kHz. Just buy some Roxul absorption (something made from laundry lint) to add to the nearfield wall areas just around the bass/midrange horn mouths. You can pin 2' x 2' squares of the 1" material to the walls using T-pins without leaving a significant mark on the walls. I just added a bunch of 2' x'2' squares to the front wall, then began subtracting them symmetrically from the farthest locations around the loudspeakers, until I began to see the RT curves and ETC curves begin to change.
The asymptotically decreasing EDT curve (light cyan trace) tells you that your loudspeakers are doing yeoman's duty keeping early acoustic reflections off the walls of the room. Perhaps more on that subject later.
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Another plot to look at is the energy-time curves (ETC) from the "Filtered IR" plots within your measurements:
This plot tells you if you've got any large reflections from just around the loudspeakers (i.e., the first 5-10 ms around the loudspeakers), and also tell you if you've got strong reflections arriving from the sides or back of the room (including ceiling and floor bounce). With fully horn-loaded loudspeakers, you will see this immediate drop in SPL within the first 2-3 ms of the initial impulse response (which is very good and is what you want), which is another way to see the fully horn-loaded loudspeakers keeping early reflections off the room's walls and ceiling. The measurement I used was accomplished using a thick absorption pad on the floor (about 2m wide between the loudspeaker and the microphone) to catch the floor bounce.
Remember that the total delay times include the total path length of sound from the loudspeaker, to the reflector(s), then back to the recording microphone. If you draw a plan view of your room's layout, you can see these primary reflections from the axial modes of the room and even the strongest tangential modes (i.e., multiple reflection modes) coming back to the microphone.
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The last plot I'll show is a more recent addition to the REW library--the RT decay plot:
As you can see, this plot is a bit more involved in terms of what you can see. In general, what this plot tells you is finer grain room decay information--especially at lower frequencies.
I'll leave this graph to your imagination for now, but note that there is a great deal of information about your room's acoustics that's displayed here.
There are probably more graphs that are useful in looking at room acoustics, but the ones I typically use are shown above.
Chris
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Maybe first describe what is actually bothering you with your sound system. Then the next steps can be taken.
Horns have a defined radiation, you should have less wall reflections than many "conventional" speaker. If your subjective analysis finds something missing, room treatment may not be the solution. Limited bass response will not get better with "bass traps", which is a very blurry concept anyway.
There is no use and need in absorbing any reflection that you will have in your room.
With your speakers and room, if you ask 5 different commercial sellers of "room tuning gear", I fear you will end up with 5 different lists what to buy, one more expensive than the other. There is very much guessing and spilled snake oil in that area and these guys don't stop selling you stuff even when you can't even enter your room any more, because of all the reflecting, absorbing, diffusing and trapping gear. Last thing will be nano sticker quantum modifier, to place on the rear of your toilet seat.
"Room tuning" can be helpfull, but it is not the only way to a good audio reproduction and satisfying listening experience.
If you ask me, first is to have some kind of carpet on the floor, second are curtains to screen large glas areas like windows. This is about 90% of the room tuning you need, the last 10% are options. A room without reflections is no place where you will like listening to music.
Horns have a defined radiation, you should have less wall reflections than many "conventional" speaker. If your subjective analysis finds something missing, room treatment may not be the solution. Limited bass response will not get better with "bass traps", which is a very blurry concept anyway.
There is no use and need in absorbing any reflection that you will have in your room.
With your speakers and room, if you ask 5 different commercial sellers of "room tuning gear", I fear you will end up with 5 different lists what to buy, one more expensive than the other. There is very much guessing and spilled snake oil in that area and these guys don't stop selling you stuff even when you can't even enter your room any more, because of all the reflecting, absorbing, diffusing and trapping gear. Last thing will be nano sticker quantum modifier, to place on the rear of your toilet seat.
"Room tuning" can be helpfull, but it is not the only way to a good audio reproduction and satisfying listening experience.
If you ask me, first is to have some kind of carpet on the floor, second are curtains to screen large glas areas like windows. This is about 90% of the room tuning you need, the last 10% are options. A room without reflections is no place where you will like listening to music.
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I agree with this recommendation. I use 59” tall by 20” wide panels, 3” thickness. Comfortboard 80 material with polyester weave covering.
That's horrible advice.
So you obviously never listened in a GOOD room. Try to find a useful studio somewhere near you and ask if you can have a visit and a listen. Then let's talk again.
Carpets and curtains only dampen the highest frequencies. Put 1-2cm thickness in and have a look what you absorb:
http://www.acousticmodelling.com/porous.php
Rooms make their main problems in the low frequency area (20-100Hz) and transition area (80-300Hz). Carpets and curtains will not change ANYTHING in that areas - the room will still sound "boxy" and different at every position - but now dull.
When you get serious with room tuning go to serious people - acoustic people who build studio rooms. Thay also do good listening rooms and know the rules and how to build stuff.
When someone wants to sell a foam panel to put on the wall or starts with these nice wood diffusors ... go away, it's wasted money. You are right - resellers often have no idea about acoustics and what is important. They want to sell. And MOST of these acoustic products don't make a lot of sense ...
Please re-read what kind of condo the thread starter has and how he wants to use it.
It is for rent and he and his wife live there. It is no dedicated listening room.
Any bass related room tuning will need two components: Volume and mass. No way around it. If someone doesn't understand that, I'm sorry. I don't think he can integrate any of this into his housing situation.
Filling some shoe box with wool, drill a hole in it and put a price tag on, doesn't make a bass trap. Just to make money such "room treatment" is sold to unknowing people with usual mostly modal problems. Some light weight foam edges placed in a corner are more a placebo than any help.
You got to be realistic about your acoustic problems and what you CAN do about it.
Starting at the source is a better idea than creating a problem and then throwing some unrealistic, money consuming fix on it.
So, in the end, carpet and curtains are realistic, anything in the bass region nonsense for him.
He should better invest his money in some Dirac or compareable, usefull frequency treatment. Usually I don't recommend Dirac, because it is overpriced, for the same money you get a nice (Denon?) HT receiver with Audessey MultEQ-XT 32 included, that will work like a charm in stereo (even Bi-amping).
Of course, you can not recommend such economical solution to an serious audiophile, even if it would solve a lot more problems than he can imagine.
It is for rent and he and his wife live there. It is no dedicated listening room.
Any bass related room tuning will need two components: Volume and mass. No way around it. If someone doesn't understand that, I'm sorry. I don't think he can integrate any of this into his housing situation.
Filling some shoe box with wool, drill a hole in it and put a price tag on, doesn't make a bass trap. Just to make money such "room treatment" is sold to unknowing people with usual mostly modal problems. Some light weight foam edges placed in a corner are more a placebo than any help.
You got to be realistic about your acoustic problems and what you CAN do about it.
Starting at the source is a better idea than creating a problem and then throwing some unrealistic, money consuming fix on it.
So, in the end, carpet and curtains are realistic, anything in the bass region nonsense for him.
He should better invest his money in some Dirac or compareable, usefull frequency treatment. Usually I don't recommend Dirac, because it is overpriced, for the same money you get a nice (Denon?) HT receiver with Audessey MultEQ-XT 32 included, that will work like a charm in stereo (even Bi-amping).
Of course, you can not recommend such economical solution to an serious audiophile, even if it would solve a lot more problems than he can imagine.
He is ready to mount a very heavy wood diffusor on the wall ... would say this is dedication enough for some useful room improvement.
Back to reality - what is called "basstrap" from most manufacturers does nothing or very little at low frequencies. You would need complete walls of this to see an effect. (I have in my studio room - and still have some room resonances).
Low frequencies and room resonances are "geometric" problems and need to be tackled "geometrically" - position of speakers and woofers. You can even solve these when you can put a double bass array in your room or Dirac ART seems very promising. But even 2 subs on the perfect spot can make a huge difference.
BUT the transition area 100-300Hz needs to be (and can be) absorbed when you want a "controlled" room with no/less "boxy" sound. This is the more problematic the smaller and lower the room is. And here some corner absorption works very well. Build absorber panels with at least 10cm depth. Get a transparent screen for your projector and put 20cm absorption behind it.
With a proper room concept you can hide and integrate these measures in your room and take them with you to your next house.
But at one point I'm alike with Turbowatch - just throwing some expensive room tuning stuff in the room is wasted money. Build proper absorbers and find places where you can hide or integrate them. Build plenty of them and your room and listening experience changes A LOT.
(Btw - the room itself also "feels" better and more cosy with less reverb. The "bedroom effect"
)
Well, somewhere in between the extreme positions of: "it's too hard--get out your checkbook"...and "it's too hard and too expensive--you can't really do much but these [mostly ineffective] treatments" is a vast domain of DIY acoustic treatments. I've found that cut-and-try approaches work quite well to dial in the room by ear, when coupled with the RT60 plot, give you good guidance on how to apply enough absorption in-room (particularly nearfield around the loudspeakers and the listening positions). That's how I approached my room's acoustic problems, and found a good compromise.
Understand that acoustically treating any room always makes the room feel a little smaller. That's always the tradeoff in any treatment approach. The first thing to control (economically) is total absorption in-room. Any money and time you have left over can be used on diffusion, but candidly, I found home furnishings and architectural details of the existing room can be used to avoid having to build diffusers. YMMV.
If you've got lots of cash or copious amounts of time and woodworking skills, those pseudo-random block diffusors (a.k.a., "corrugated" diffusers) that you showed above can help to mitigate the amount of absorption used, but note that those type of diffusors are severely limited in terms of their frequency bands of effectiveness. PWK used (and promoted) curved diffusers over the corrugated designs. The linked paper from JAES also discusses why curved diffusers are still preferred over the corrugated types for the majority of cases, especially for those with fully horn-loaded loudspeakers. Here are a couple of shots of an alternative to plywood (and putting screw holes in your walls):
In your listening room, after you've got the absorption times (reverberation times- RT) under control, then you can apply curved diffusers quite easily to any remaining bare wall surfaces--something that takes just a few screws into a wall for an entire panel. The reverse (inside) portion of the curved diffusers can function as bass traps if they are fitted with absorption material in depth. This is also the same principles used in the diffuser/bass trap designs that sit out on the floor of the room away from the walls (like Mike Beasley [mikebse2a3] uses on the K-forum). Either way will work, but the floor-located tube traps take up significant real estate in-room, while the wall-mounted curved diffusers do not.
Using the RT60 plot (an example is posted above), you can see if you've got enough total absorption in-room for all frequencies of interest. Any frequencies below ~200 Hz in your listening room are likely in the "sparse mode region" of the room where the room boundaries themselves become part of the generated standing waves, and directivity of acoustic waves no longer has meaning. Above ~200 Hz, exact location of absorption placement in-room matters.
This is where most advice that you see in this thread, above, for frequencies above 200 Hz are probably a bit wide of the mark. I posted the ETC (Filtered IR) plot and the RT60 Decay curves to show that loudspeaker full-range directivity matters...a lot...in avoiding most of the nearfield reflection issues found with direct radiating and hybrid horn/direct radiating loudspeakers.
Probably not nearly as effectively as some absorption in the same places.
I'd recommend those highly. I use those in my listening room, and have found real advantages to using them there.
Understand. Budgetary constraints have always been on my list of constraints, too.
I've pretty much enumerated what I think are good alternatives, above. I'd recommend against rock wool in-room, instead using the lint-type absorption material (like Auralex Sonofiber)-- for health reasons. I ended up buying two full boxes of 2' x 2' Sonofiber squares, using about 1 1/4 boxes total.
Chris
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Chris, thanks for your input, it's potentially useful. I say potentially, because I have ample information at hand, but I am at a loss to interpret it. (I've only been doing this for a minute; everyone has to start somewhere, right?)
Here is my RT60 plot:
my Energy Time Curve:
and finally, the RT Decay plot:
I guess my biggest issue here is not that I necessarily have bad sound in my room, but I feel like I'm shooting in the dark with regards to it. I have spent a significant amount of time, effort and money on building my system and now that I'm nearing a relative endgame with regards to improvements, the one thing I've not addressed is the room. the good part of the room is that it's a decent sized area, but being in a small, 1250sf condo, it serves multiple functions: it's my living room, dining room and kitchen. It's also packed with stuff: bookshelves, furniture, a kitchen island, dining table, my spouse's home office etc. It's irregularly shaped, as well, with a soffit running around 3/4 of the room. I've built recording studios, so I have an idea of how to treat a room completely, but I'm at a loss with how to do it selectively, tuning for specific frequencies, with WAF as a consideration.
so here's what it looks like from the MLP (yes, I need to do some cable management):
and here's my room layout, mostly to scale:
Attachments
The RT60 curve looks pretty good already, so you seem to have a requisite amount of total absorption in-room. Adding more absorption to your room will likely only make it feel smaller. Also, it appears that you don't really need a lot more diffusion from looking at your hand-drawn floor plan view. You seem to have plenty of furnishings that provide that duty already.
I can say that the coffee table will affect your imaging, unless something that's quite absorptive is laid across the entire top of the table to eat those early reflections. I recommend trying listening to your setup, but with that coffee table moved out of the way entirely, then have a critical listen for imaging and soundstage size. The bar cabinet, to the extreme right, will also affect the soundstage and imaging if it is acoustically reflective. It looks to be too close to the right-side listening position on the sofa
Moving your loudspeakers out in front of the credenza a bit more might also strengthen the phantom center imaging (strongly).
The filtered IR (ETC) curve looks like both axes of the plot are zoomed too fare out (and once again, I'm asking for a much more zoomed-in plot). This may be a function of the print utility within REW. If you can't get the axes to stay at something like 70 ms full-scale horizontally and -80 dB full-scale vertically using the print screen function within REW, then I'd recommend first zooming in both axes manually, then taking a screen shot with a separate screen shot utility. I use "Snipping Tool" that comes with Windows--but I don't know what screen shot utility comes with a Mac (as I presently understand that you're using).
It appears like you have some irregularities in the ETC within the first 70 ms, but it's zoomed so far out that I can't really read it, especially the horizontal scale--by a factor of 14(!).
The RT60 Decay curve looks like you've got a lot of reverberation below ~40 Hz. This is quite difficult to do much about, since a wavelength of sound is ~28 feet at 40 Hz. You'll need a bass trap that's at least 7 feet long to do much about those frequencies (a 1/4 wavelength tube trap, that is). You could try to lay down a couple of flat Owens-Corning 703 or 705 panels end-to-end across the boundary of the back wall and the floor, with one end against a corner or blocked off by the end of a bookcase, and the other end open to air. This will be effective down to ~30-35 Hz.
The rest of the spectrum below that frequency will be pretty much undamped, however. This is probably a consequence of the smaller total room volume (i.e., room size) that you have. This is a problem that almost everyone with a nominally sized home listening room has. Most people tend to ignore this region of the audible spectrum, since it's represented by 5-string bass (electric) or a bass "E" string extension on a double bass, and the main impulse of a kick drum. Having a listening room with a long dimension approaching 30-40 feet is the most effective way to control RT60 times below 40 Hz, in my experience.
Chris
I can say that the coffee table will affect your imaging, unless something that's quite absorptive is laid across the entire top of the table to eat those early reflections. I recommend trying listening to your setup, but with that coffee table moved out of the way entirely, then have a critical listen for imaging and soundstage size. The bar cabinet, to the extreme right, will also affect the soundstage and imaging if it is acoustically reflective. It looks to be too close to the right-side listening position on the sofa
Moving your loudspeakers out in front of the credenza a bit more might also strengthen the phantom center imaging (strongly).
The filtered IR (ETC) curve looks like both axes of the plot are zoomed too fare out (and once again, I'm asking for a much more zoomed-in plot). This may be a function of the print utility within REW. If you can't get the axes to stay at something like 70 ms full-scale horizontally and -80 dB full-scale vertically using the print screen function within REW, then I'd recommend first zooming in both axes manually, then taking a screen shot with a separate screen shot utility. I use "Snipping Tool" that comes with Windows--but I don't know what screen shot utility comes with a Mac (as I presently understand that you're using).
It appears like you have some irregularities in the ETC within the first 70 ms, but it's zoomed so far out that I can't really read it, especially the horizontal scale--by a factor of 14(!).
The RT60 Decay curve looks like you've got a lot of reverberation below ~40 Hz. This is quite difficult to do much about, since a wavelength of sound is ~28 feet at 40 Hz. You'll need a bass trap that's at least 7 feet long to do much about those frequencies (a 1/4 wavelength tube trap, that is). You could try to lay down a couple of flat Owens-Corning 703 or 705 panels end-to-end across the boundary of the back wall and the floor, with one end against a corner or blocked off by the end of a bookcase, and the other end open to air. This will be effective down to ~30-35 Hz.
The rest of the spectrum below that frequency will be pretty much undamped, however. This is probably a consequence of the smaller total room volume (i.e., room size) that you have. This is a problem that almost everyone with a nominally sized home listening room has. Most people tend to ignore this region of the audible spectrum, since it's represented by 5-string bass (electric) or a bass "E" string extension on a double bass, and the main impulse of a kick drum. Having a listening room with a long dimension approaching 30-40 feet is the most effective way to control RT60 times below 40 Hz, in my experience.
Chris
here's a better ETC:
I apologize, I'm still learning how to optimize REW and letting it show me the default charts, simply because I don't really understand what I should be reading or how to get that, but thanks to your cajoling and advice, I think I'm slightly getting a better hang of it.
I moved the speakers out so that they're about 8" in front of the credenza and pushed the coffee table up against the credenza, the best I can do in this tight space. It did improve the imaging and phantom center quite a bit, but ultimately, it's not a sustainable situation for WAF, but for listening sessions when I'm home alone, it's doable. the rest will be tricky, as the back boundary wall is bare to serve as a projector screen.
I apologize, I'm still learning how to optimize REW and letting it show me the default charts, simply because I don't really understand what I should be reading or how to get that, but thanks to your cajoling and advice, I think I'm slightly getting a better hang of it.
I moved the speakers out so that they're about 8" in front of the credenza and pushed the coffee table up against the credenza, the best I can do in this tight space. It did improve the imaging and phantom center quite a bit, but ultimately, it's not a sustainable situation for WAF, but for listening sessions when I'm home alone, it's doable. the rest will be tricky, as the back boundary wall is bare to serve as a projector screen.
That ETC looks pretty good.
I've always believed that there is way too much focus on electronics among "audiophiles" that almost exclusively focus on improvements in electronics to improve sound quality, when they are leaving at least 2x-->5x sound quality improvements on the table by not cleaning up their listening room acoustics and acquiring better performing loudspeakers.
Chris
Clearly, I understand. I used to put three Sonofiber squares across the front of my flatscreen TV above the mantle for hi-fi listening, and found that the subjective position of the phantom center image moves down about 1-2 feet...(!). Other temporary tweaks accomplish amazing changes in sound quality improvement, I've found.
I've always believed that there is way too much focus on electronics among "audiophiles" that almost exclusively focus on improvements in electronics to improve sound quality, when they are leaving at least 2x-->5x sound quality improvements on the table by not cleaning up their listening room acoustics and acquiring better performing loudspeakers.
Chris