I never understood why people tell room acoustics is expensive! How much is a pack of rockwool?
It's about 10 bucks per m², up to 30 when you take nicer material and more thickness. The rest is optics - you can spend as much as you like for that.
The earlier you plan acoustics during building/setting up your room the cheaper it is.
Could you set a 60dB range, maybe 90-30dBSpl?
Your reverb curves are not bad. You have a problem around 300Hz and a rise in the 2-5kHz area - the most sensitive area of the ear. And of course the high frequency fall off. Low frequencies are pretty good - american light walls house?
So the first goal would be to lower the over all reverb - BROADBAND! So only use deeper absorption - don't use any if that's not possible.
There are so many places where you could add absorption! Corner wedges are efficient for what you need (lower reverb >80Hz) and you have a lot of possibilities around your ceiling to install something there! Use the area behind your speakers and esp the corner of your right speaker. Put something to the shelves behind your listening postion!
Here is my cinema baffle - there is 40cm absorption and all the speakers behind it. Google for home cinema - they often do great integration of room design and acoustics.
You can make complete walls out of these wood stripe panels in all kinds of colours. Even hide doors with them. Or just use white fabric to cover stuff. You can just enlarge the soffits, fill the corner with absorption and wrap white fabric around. Add some soft LED lights for some benefits for the room.
It takes some creativity but your whole space and life will benefit from better acoustics!
You can make complete walls out of these wood stripe panels in all kinds of colours. Even hide doors with them. Or just use white fabric to cover stuff. You can just enlarge the soffits, fill the corner with absorption and wrap white fabric around. Add some soft LED lights for some benefits for the room.
It takes some creativity but your whole space and life will benefit from better acoustics!
Attachments
Sometimes these room-acoustics related plots tell you more than just information about room acoustics. In this case, it appears that the crossover transition band between the bass bin and the midrange horn could be a bit wide or even perhaps a bit too low in frequency for the midrange horn to continue to control its vertical polars.Here is my RT60 plot:
Recall that I said that the loudspeakers were doing yeoman's duty keeping early reflections off the nearby walls, above. In this case, it looks like the midrange horn may be losing its polar control around 320 Hz and is putting a bit more nearfield energy into the ceiling/floor than might be desired.
If you get a chance, you might try moving the crossover point up perhaps 50 Hz by tweaking your PEQs--then looking again at the RT60 plot (particularly the peak in the EDT [early decay time] curve) to see if moving the crossover point up a bit starts to smooth out the peak in the EDT curve at 310-320 Hz. This will likely result in a pretty subtle shift in the overall sound quality, but you should be able to hear a bit more "damped" room response across this low midrange band, perhaps a bit smoother and more consistent in terms of vocal timbre or other low midrange instrumentation.
In general, I don't really think you need much more absorption in-room. I think other advice to lower the RT curves even more are forgetting that you have full-range directivity control. Another key insight to what's occurring is the decreasing EDT curve with frequency, which says that the early reflection issues are under control (unlike direct radiating loudspeakers that others might use in their listening rooms that lose most of their horizontal directivity control below 800-1500 Hz).
JMTC.
Chris
The main thing is that you have obviously done something, whether intentional or not to make your room better than most.
We see too many great systems posted here in rooms that look like echo chambers. Yours is better.
Chris has made some very good suggestion for small tweaks to what you now have.
We see too many great systems posted here in rooms that look like echo chambers. Yours is better.
Chris has made some very good suggestion for small tweaks to what you now have.
The mid horn (PRV Audio 18”w x 10”h WG45-50) and driver (PRV D2200PH) drop precipitously at exactly 400 Hz, so I’m not sure what’s going on with the loss of directivity control, unless it’s something endemic to the LaScala bass bin, which in my case, is driven by a JBL D2225H.
My next measurement session will be to focus on the left driver and tune that as needed. I’m curious how that reads with the lack of a corner. I’ll be sure to move the coffee table out of the way to rule it out as a source of reflection
Usually, the reason for a precipitous decline in SPL on-axis on the low end is because the horn completely loses directivity control. In straight-sided horns (like the one you've got), this occurs typically at the frequency where the longest dimension of the horn mouth corresponds to a half wavelength of sound. For your 17.71" x 9.84" mouth dimension horn, that occurs at about 400 Hz (if you subtract the mouth flange width).
That doesn't mean that the horn is putting out nothing at 400 Hz...rather it means that the horn isn't putting out much on-axis, but instead the horn is putting out almost all its output into an almost 360 degree polar pattern--in both axes (vertically and horizontally...as long as the driver's diaphragm remains acoustically loaded). So if you raise the crossover point a little, you might be able to avoid that energy being deposited all over the room--nearfield.
The La Scala "W" section bass bin polars only get narrower, somewhat slowly, as the frequency rises above 400 Hz. Since that bass bin doesn't have a truncated mouth like the Belle, it actually behaves quite well at higher frequencies and doesn't collapse down its directivity pattern as much as the Belle, Khorn, and Jubilee bass bins experience. So the La Scala bass bin should handle a slightly higher crossover frequency quite well.
Chris
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Rather than just buy stuff, I thought I’d do a test with stuff that I had on hand, before I threw money at a solution that may or may not work. I had a sheet of 1-1/4 memory foam and some 3” foam blocks that I tacked up in the right corner and behind the left speaker. I didn’t really expect it to make much of a difference, but much to my surprise, the bass seems tighter and there seems to be additional improvement in imaging. Measurements to follow.
It looks like I may be building some bass traps sooner than later.
It looks like I may be building some bass traps sooner than later.
slow progress, but I've made some diffusion baffles for the blank wall space behind & above the speakers.
I'm making them from white oak, salvaged from a 230 year-old farm house. I still have to sand and finish them, I'm thinking I'll use a stain that brings out the tannins in the wood and makes it look old again. I also have frames made for a pair of bass traps (I still need to make a third); I hope to get them done this weekend, provided I can find a supplier of Owens Corning 703, locally. I'll cover them with a fabric that's somewhere between burlap and linen. I showed the photos to my spouse and told her that I'm "making art again" and her response was to roll her eyes and proclaim "it looks like speaker stuff to me." She's been pretty supportive of my hobby, but I can tell I'm pushing the limits of WAF pretty hard. That said, I have a pair of 24" x 24" x 44" horns in a 1200 sf inner city apartment; I'm doing pretty good.
I'm making them from white oak, salvaged from a 230 year-old farm house. I still have to sand and finish them, I'm thinking I'll use a stain that brings out the tannins in the wood and makes it look old again. I also have frames made for a pair of bass traps (I still need to make a third); I hope to get them done this weekend, provided I can find a supplier of Owens Corning 703, locally. I'll cover them with a fabric that's somewhere between burlap and linen. I showed the photos to my spouse and told her that I'm "making art again" and her response was to roll her eyes and proclaim "it looks like speaker stuff to me." She's been pretty supportive of my hobby, but I can tell I'm pushing the limits of WAF pretty hard. That said, I have a pair of 24" x 24" x 44" horns in a 1200 sf inner city apartment; I'm doing pretty good.
Sorry to dissapoint you ... but this diffuser will only work in the region of 7000 Hz an upwards 20000 hz.The wavelength of 1000 Hz is 34cm
and at 100Hz it is 3.4 meters. so if you want to diffuse lower frequency the features needs to be bigger. Try to build BAD panels instead!
Faster, more effective, cheaper....
and at 100Hz it is 3.4 meters. so if you want to diffuse lower frequency the features needs to be bigger. Try to build BAD panels instead!
Faster, more effective, cheaper....
https://www.oliverprime.com/prd/index.php
https://www.diyaudio.com/community/...ot-sound-diffuser-panels-step-by-step.269366/
I've made 2ft x 2ft skyline diffusers, they made a big difference behind some small speakers. Those were small speakers, tho. Area covered is important, so I think the depot diffusers seem like a good idea. Skylines start to be lots of wood and weight to cover much area.
https://www.diyaudio.com/community/...ot-sound-diffuser-panels-step-by-step.269366/
I've made 2ft x 2ft skyline diffusers, they made a big difference behind some small speakers. Those were small speakers, tho. Area covered is important, so I think the depot diffusers seem like a good idea. Skylines start to be lots of wood and weight to cover much area.
2 of 3 bass traps are done:
And installed
I still need to build one more for the other half of the RH corner, but so far, so good. They seem to perform better than my ad hoc foam traps, but measurements will say for sure. The diffusers need a little more stain, hopefully, I‘ll have them completed by this weekend.
And installed
I still need to build one more for the other half of the RH corner, but so far, so good. They seem to perform better than my ad hoc foam traps, but measurements will say for sure. The diffusers need a little more stain, hopefully, I‘ll have them completed by this weekend.
Looks much too small and too thin to be effective for room modes I'm afraid, but for mids, sure! Hence, you might want to experiement where to put those.
To have effect on room modes, which make the main issue for bass, you would need about hundred of those panels. Perhaps put on corners of the room with air space behind maybe tens had some effect.
Modes happen with room sized dimensions, so if your room had 6m longest dimension the lowest mode has 12m long wavelength. Now, imagine 12m diameter ball, and compare size of the acoustic treatment to that, and it's much too small, acoustically invisible to such long wavelength. If it was perhaps quarter wavelength in size, it would be already effective. Basically this means such absorber treatment needs to approach size of the room, eat perhaps quarter of each dimension, to be effective for low room modes. Thus, instead of absorption more frequency targeted resonators are utilized to help with bass, to save space.
For absorbers many things affect like surface area, type of material, thickness, whether it is positioned in velocity or pressure node of a mode, incident angle if shorter than room sized wavelengths. Material seems to be insulation so very good absorption properties for a velocity node, But for example 100Hz is 3.4m long so 1m x 1m panel might have some effect on it, and more and more for frequencies above, and less and less below.
To have effect on room modes, which make the main issue for bass, you would need about hundred of those panels. Perhaps put on corners of the room with air space behind maybe tens had some effect.
Modes happen with room sized dimensions, so if your room had 6m longest dimension the lowest mode has 12m long wavelength. Now, imagine 12m diameter ball, and compare size of the acoustic treatment to that, and it's much too small, acoustically invisible to such long wavelength. If it was perhaps quarter wavelength in size, it would be already effective. Basically this means such absorber treatment needs to approach size of the room, eat perhaps quarter of each dimension, to be effective for low room modes. Thus, instead of absorption more frequency targeted resonators are utilized to help with bass, to save space.
For absorbers many things affect like surface area, type of material, thickness, whether it is positioned in velocity or pressure node of a mode, incident angle if shorter than room sized wavelengths. Material seems to be insulation so very good absorption properties for a velocity node, But for example 100Hz is 3.4m long so 1m x 1m panel might have some effect on it, and more and more for frequencies above, and less and less below.
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I don't think you can argue with physics, when it comes to "bass traps". Anyway, since a lot of people fall for such from commercial offers, better call them "money traps". We all know, if money can be made from a legend, it will live on...
Facts of low frequency are even harder to sell, as some kinds of room treatment have audible results from reducing reflections and absorbing higher frequency. So fact and fiction get mixed up...
If you imagine a single woofer in a room, it will emit it's sound wave in all directions, 360°. Now you place a bass trap with a hole in it in the same room. How can anyone expect this “trap” to catch more than the energy we find on the surface of the hole? Is there some magic that re-focuses the sound waves and directs them inside the bass trap?
What the TS does, seen from the picture, is putting an high frequency absorber in front of his woofer. This may change his reception of bass in the room a little. Just like putting a curtain in front of the sub or a heavy towel over it.
His reaction, if one or two traps don't work, let's build more, can be compared to someone with a broken leg taking an Aspirin tablet to cure it. If one doesn't help, maybe take the whole bottle?
In this picture, the doctor casting the leg would be a DSP and a measuring microphone.
Facts of low frequency are even harder to sell, as some kinds of room treatment have audible results from reducing reflections and absorbing higher frequency. So fact and fiction get mixed up...
If you imagine a single woofer in a room, it will emit it's sound wave in all directions, 360°. Now you place a bass trap with a hole in it in the same room. How can anyone expect this “trap” to catch more than the energy we find on the surface of the hole? Is there some magic that re-focuses the sound waves and directs them inside the bass trap?
What the TS does, seen from the picture, is putting an high frequency absorber in front of his woofer. This may change his reception of bass in the room a little. Just like putting a curtain in front of the sub or a heavy towel over it.
His reaction, if one or two traps don't work, let's build more, can be compared to someone with a broken leg taking an Aspirin tablet to cure it. If one doesn't help, maybe take the whole bottle?
In this picture, the doctor casting the leg would be a DSP and a measuring microphone.
when I was an apprentice carpenter in the mid 90's, the old hippie carpenter I worked for had 2 seemingly contradictory maxims he that imparted on me. The first was "perfect is good enough," meaning that one should strive towards perfection in their work as much as possible and not tolerate avoidable, obvious mistakes, and consistenlty deliver the highest quality, as much as possible.
the 2nd maxim was "don't let perfect be the enemy of good," meaning that ultimately, there is a point of diminishing returns in our pursuit of perfection. There is an inflection point in cost benefit analysis, where continuing to pursue perfection becomes untenable, where we begin chasing our tails in our quest of an unreachable ideal.
Before:
I have to not only address room modes, which in my case are generally below 40Hz, which is difficult enough within the constraints of my room layout, but also not go so far as to push the boundaries of WAF, which in my case, with 24"w x 24"D x 42" high (61cm x 61cm x 107cm) horn speakers in a 1200 sf, (112 square meters) 2-bedroom condo, I am clearly at my limit. To address the critics, I'm aware that my solutions don't completely address my room modes, however, doing nothing is not the answer. Empirically, the bass traps, (I've placed one behind the speaker on the left and the other in the corner, behind the speaker on the right, with my ad hoc foam trap in the other half of the corner, waiting for the third trap to be completed) while not fully damping the low frequencies, certainly appears to improve the reverberation. To my ears, the low frequencies are tighter and more concise and the imaging is significantly better. I would make the case that doing something that achieves an imperfect, but improved result, is better than doing nothing. Naturally, measurements with either prove my assertions correct or show that what I thought was an improvement, was actually a step backwards.
currently:
the 2nd maxim was "don't let perfect be the enemy of good," meaning that ultimately, there is a point of diminishing returns in our pursuit of perfection. There is an inflection point in cost benefit analysis, where continuing to pursue perfection becomes untenable, where we begin chasing our tails in our quest of an unreachable ideal.
Before:
I have to not only address room modes, which in my case are generally below 40Hz, which is difficult enough within the constraints of my room layout, but also not go so far as to push the boundaries of WAF, which in my case, with 24"w x 24"D x 42" high (61cm x 61cm x 107cm) horn speakers in a 1200 sf, (112 square meters) 2-bedroom condo, I am clearly at my limit. To address the critics, I'm aware that my solutions don't completely address my room modes, however, doing nothing is not the answer. Empirically, the bass traps, (I've placed one behind the speaker on the left and the other in the corner, behind the speaker on the right, with my ad hoc foam trap in the other half of the corner, waiting for the third trap to be completed) while not fully damping the low frequencies, certainly appears to improve the reverberation. To my ears, the low frequencies are tighter and more concise and the imaging is significantly better. I would make the case that doing something that achieves an imperfect, but improved result, is better than doing nothing. Naturally, measurements with either prove my assertions correct or show that what I thought was an improvement, was actually a step backwards.
currently:
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You should stop calling your absorbers "bass traps". They are just a piece of dampening material in a frame to hold them together. No bass is trapped in your builds. Please don't blame me for the physic's no one can change.
You seem to be confused by sales talk form commercial sellers of such expensive, made to order, no return or refund articles. There is a very fine border between acoustic reality and selling useless, overpriced phantasy products to people that have too much money.
In your case I would measure and compare, not build a ton of objects that might stress your relationship...
PS maybe don't exite the modes that bother you, instead of trying to catch them when it is too late? They are no rodents you can lure into a trap.
You seem to be confused by sales talk form commercial sellers of such expensive, made to order, no return or refund articles. There is a very fine border between acoustic reality and selling useless, overpriced phantasy products to people that have too much money.
In your case I would measure and compare, not build a ton of objects that might stress your relationship...
PS maybe don't exite the modes that bother you, instead of trying to catch them when it is too late? They are no rodents you can lure into a trap.