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Shootout between JBL M2 and Revel Salon 2

that doesn't make any sense at all and is objectionably false statement. you have no authority nor data to insinuate that diffusion is only "suitable" for professional recording studios and mastering studios..

LOL Do you have authority to claim otherwise? :D

As I stated, recording/mixing studios are not really places where you would like to enjoy your music. Have you ever been to one and tried lsitening music in one of them?
 
your commentary leads me to believe you don't actually have any experience with reflection phase gratings or modifying a room if you think adding specular reflectors at side walls (to create many sparse reflections) or reflection phase gratings (to convert sparse reflection into many reflections of lower gain) somehow automatically result in a "dead" sound.

Such treatment would typically result in reducing Topt to values below 0.25 sec. For most people that would be a room with "dead" sound. Once again, have you ever been to a professional studio treated that way?
 
LOL Do you have authority to claim otherwise? :D

As I stated, recording/mixing studios are not really places where you would like to enjoy your music. Have you ever been to one and tried lsitening music in one of them?

this is perhaps one of the most ignorant and absurd statements i've read regarding studios: to imply that they are somehow not "places to enjoy your music".

you do not have any authority to imply what one does in their home listening room. to insinuate that "diffusion" is only appropriate for professional recording studios is absurd. you clearly do not understand the acoustics involved of what diffusers "do" to the indirect sound-field and the subsequent psycho-acoustic effects humans perceive them as. diffusers are delightful tools in home listening spaces (small room acoustics) that can aid in solving a myriad of acoustical problems/acoustical distortion - should the user be so inclined.

next you're going to tell me that studio monitors such as JBL M2 shouldn't be used in the home, either.

and you need to be careful about what you consider a "recording/mixing studio". too many poorly designed spaces out there claiming to be "recording studios" by people who have no idea what they're doing; it's akin to a poor loudspeaker being marketed as a "neutral studio monitor" - even though it clearly is not. same common issue with people claiming their listening space coated in thin foam is somehow a professional designed/engineered "studio".

properly designed control/mix/mastering rooms are an absolute delight to listen to music in and are very comfortable / no long-term fatigue.
 
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you do not have any authority to imply what one does in their home listening room. full stop. to insinuate that "diffusion" is only appropriate for professional recording studios is flat-out absurd. you clearly do not understand the acoustics involved of what diffusers "do" to the indirect soundfield and the subsequent psycho-acoustic effects humans perceive them as. diffusers are delightful tools in home listening spaces (small room acoustics) that can aid in solving a myriad of acoustical problems/acoustical distortion - should the user be so inclined.

next you're going to tell me that studio monitors such as JBL M2 shouldn't be used in the home, either.

and you need to be careful about what you consider a "recording/mixing studio". too many poorly designed spaces out there claiming to be "recording studios" by people who have no idea what they're doing it's akin to a poor loudspeaker being marketed as a "studio monitor" - even though it clearly is not. same common issue with people claiming their listening space coated in thin foam is somehow a professional designed/engineered "studio".

properly designed control/mix/mastering rooms are an absolute delight to listen to music in and are very comfortable / no long-term fatigue.

Can I see Topt response of your speakers?
 
properly designed control/mix/mastering rooms are an absolute delight to listen to music in and are very comfortable / no long-term fatigue.

M8, if you have ever been to one you would never say that. ;)
 
M8, if you have ever been to one you would never say that. ;)

your insinuations are indicative of being in a poorly designed control room - or one with poorly designed loudspeakers (as it is a system).
and you appear to be speaking "for all control rooms" and making global claims, which makes no logical sense at all - as if they are "all the same".

it's akin to people telling me they've been in "professional recording rooms" and how it "didn't sound good" when it is just some thin foam haphazardly applied and some low-end "studio monitors" in a room. anyone can call a room a "studio" - but that doesn't make it a professionally designed studio space constructed to meet certain design requirements that is objectively neutral via the results from mix/mastering translation.

just as how any loudspeaker manufacturer can call any speaker a "studio monitor" - then a user attempts to make a global, catch-all claim about "how poor studio monitors sound" just off that one example. based on your logic, you would hear the krk rokit "studio monitors" and then proclaim to the world how studio monitors are not good/enjoyable to listen to music on.

logically, it is a complete breakdown.

why is diffusion only allowed in professional studios and not in home listening reproduction setups? i still haven't seen a valid answer for this claim.
 
Without stepping into the "studio sound" debate (I have lots of experience in studios but it has been a while) I'd venture a guess that diffusion is found less in consumer listening rooms because it tends to cost more (sometimes much more) and tends to be more visually distracting (though some like the look). That is for typical QRD/PRN diffusors; I have little experience with grate or resonant cavity diffusers for audio. Since RPG went out of business I am not sure there is a viable modestly-costing diffuser available for home use -- but I have not looked. I have seen some of the new thin panel diffusers but the few I have seen are priced more for the high-end audiophile market.

What are installers using for diffusers these days? I see plenty of pictures of high-end consumer stereo and media rooms incorporating diffusers so I know they are out there...

I have said many times, based on personal and professional observations and measurements, that my ideal room would include a mix of absorption and diffusion (and be about 2x the size of the room I have!) Diffusion breaks up higher-frequency direct reflections (in homes; some studios have much larger diffusers that go lower in frequency) without making the room "dead". IME, again fairly dated, recording control rooms primarily used absorption to kill the HF mess in a small'ish space. Mastering rooms used diffusion and absorption as appropriate and were designed to emulate the home and theater sound stage. Pictures of current studios show a similar trend, at least the few I have seen (not something I pay attention to now), with movie mastering rooms in particular being more spacious with a mix of diffusion and absorption.

Personally I am OK with a "dead" room; I get much better imaging and the ambiance of the recording comes through vs. what my room does to it. Mine was until recently very dead; I removed a few panels to better fit my (gigantic) surrounds so it is a little more lively but still absorbers abound. Mainly to help reduce some nasty room modes (you can reduce bass nulls but it takes a lot of thick panels).

FWIWFM - Don
 
reflection phase gratings are relatively easy to construct, just ungodly time consuming - especially the 2-dimensional variety. although for the bandwidths most are constrained to in home residential rooms (1/2wavelength design frequency, based on distance from listening position to RPG), XPS/extruded polystyrene foam can be substituted for wood and can be cut into appropriate lengths with a simple hot knife. XPS-based RPGs make wall/ceiling mounting that much more viable (and safer) than 100s of lbs of wood to deal with.

if you have requirements for significant sq area coverage, it's wise to obtain (or find a friend with) a CNC machine and program the number pattern (MLS/pseudo-random) to construct 2-dimensional binary amplitude gratings. they are highly beneficial due to their mid/HF diffusion and increased LF absorption (than a simple porous absorber would allow). they lack temporal dispersion (since no phase shift as it is a planar surface vs variable depth wells), but that also relaxes the minimum seating distance limitation. you can cover entire boundaries with these and sufficiently damp the high-gain destructive specular reflections to be lower in gain and thus not cued on by the brain for localization, imaging, etc. - all while maintaining mid/HF diffused energy within the room to alleviate the common suckout feel as when one erroneously applies too much broadband porous absorption in the bounded space. with access to a CNC, you can easily output the printed membranes and simply use to cover the porous absorber. it makes the process quite benign. much more useful for multi-channel/surround (since there are so many active sources and thus so many "reflection points" that must be addressed for such a wide listening area) - where-as RPGs (1-dimensional, with the wells oriented vertically such that diffraction lobes develop in the horizontal plane / for lateral reflections) are more suited for 2ch stereo reproduction environments.
 
Can I see Topt response of your speakers?

Here is Topt from one of my systems, in Room2. The room is quite small, so the Topt is not really a good visualization of the decay profile of the room-speaker combination, but it gives you some indication on what values are reasonable to see.

No, it does not sound dead. Does not sound dead to me, and neither has any visitors indicated so.

Topt F205 Rom2.png
 
TOPT is an estimate of RT60 time and is only valid for very large rooms (concert halls etc.) with a diffuse field. It's not approritate for small listening rooms with dicrete specular reflections.
 
Here is Topt from one of my systems, in Room2. The room is quite small, so the Topt is not really a good visualization of the decay profile of the room-speaker combination, but it gives you some indication on what values are reasonable to see.

No, it does not sound dead. Does not sound dead to me, and neither has any visitors indicated so.

View attachment 63329

Sorry, but I have never been in a room with Topt<250 that didn't sound "dead" to me. But as long as it rocks your boat..

Btw, Topt calculation in REW has been revised to be more precise for small rooms.
 
Sorry, but I have never been in a room with Topt<250 that didn't sound "dead" to me. But as long as it rocks your boat..

Btw, Topt calculation in REW has been revised to be more precise for small rooms.

As @Bjorn explained above, Topt (or other numbers based on simple T60 calculations) is not a good or valid measure of acoustic properties in a small room. The Topt value can be the same, but the room can still sound very different.
 
As @Bjorn explained above, Topt (or other numbers based on simple T60 calculations) is not a good or valid measure of acoustic properties in a small room. The Topt value can be the same, but the room can still sound very different.

REW Topt is not a simple T60 calculation and @JohnPM already explained how he adapted it for smaller rooms. Read more here.
 
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