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RPG Modex Edge a Resonator Bass Absorber

Dialectic

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this logic doesn't make any sense to me at all.

your comment seems to insinuate that it is all for nothing if the floor reflection is not addressed. as if the rest of the room is "incompetently treated" simply because the floor is not? do kindly explain the logic in these statements.

the user could have simply had visual design requirements for the floor that superseded acoustical. or perhaps it is a mixed-use room where blockage of the floor is unwarranted.

none of which negates the other treatment that you seem to carelessly dismiss.
When I am told (ad nauseam at this point) that there is no evidence that first-reflection points on the floor matter, I don't erroneously conclude that first-reflection points on the floor don't matter. My hope that the pandemic would make us all Bayesians has not been borne out!

First-reflection points on the sidewalls, the ceiling, and the floor all matter, and when one listens to a system that images extremely well, this becomes evident.

The room in the photo of the fancy system has bass traps in the corners and absorbers on the sidewalls--all of which will help. The concert-hall-style reflectors on the ceiling are not substantially helping the room for audio listening purposes, and the fancy diffuser on the front wall between the loudspeakers is there for show: the front wall is where audiophiles tend to place their most expensive room treatments. A single Persian rug on a hardwood floor will attenuate a small amount of high-frequency energy but will otherwise leave the floor reflection intact.

This is obviously not a mixed-use room: it is a purpose-built audiophile listening room. Yet I agree that considerations other than acoustics played a major role in the design of the room. Such considerations frequently outweigh acoustic considerations in determining audiophile preferences.

I just would have thought that, with the hundreds of thousands of dollars spent on gear in this system, more attention would have been paid to the room.

Here's a more egregious example of audiophile gear lust overcoming basic acoustic considerations:

GoldmundSystem.jpg
 
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Inner Space

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When I am told (ad nauseam at this point) that there is no evidence that first-reflection points on the floor matter, I don't erroneously conclude that first-reflection points on the floor don't matter. My hope that the pandemic would make us all Bayesians has not been borne out!

Well, OK, but ... have you been experimenting during lockdown? Did you take out your pad, carpet and shag rug, in order to compare bare -vs- treated? Or perhaps overlay some reflective sheet material, just for a day? The Fraunhofer Institute did such experiments, and found the removal of floor reflections to be negative and unnatural sounding. Toole and Linkwitz found the presence or absence of floor reflections to have no net effect.

I'm all for skepticism and clean-sheet thinking, but it sounds to me as if your wife likes pad, carpet and rugs, and you've decided to make a virtue out of necessity, science be damned.
 

localhost128

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When I am told (ad nauseam at this point) that there is no evidence that first-reflection points on the floor matter, I don't erroneously conclude that first-reflection points on the floor don't matter. My hope that the pandemic would make us all Bayesians has not been borne out!

First-reflection points on the sidewalls, the ceiling, and the floor all matter, and when one listens to a system that images extremely well, this becomes evident.

The room in the photo of the fancy system has bass traps in the corners and absorbers on the sidewalls--all of which will help. The concert-hall-style reflectors on the ceiling are not substantially helping the room for audio listening purposes, and the fancy diffuser on the front wall between the loudspeakers is there for show: the front wall is where audiophiles tend to place their most expensive room treatments. A single Persian rug on a hardwood floor will attenuate a small amount of high-frequency energy but will otherwise leave the floor reflection intact.

This is obviously not a mixed-use room: it is a purpose-built audiophile listening room. Yet I agree that considerations other than acoustics played a major role in the design of the room. Such considerations frequently outweigh acoustic considerations in determining audiophile preferences.

I just would have thought that, with the hundreds of thousands of dollars spent on gear in this system, more attention would have been paid to the room.

you insinuated that the room is "incompetently treated", distinguished it from those that are (apparently) "properly conceived and executed" (and other form of tirade); attacking the room all because the floor was not adequately treated to your liking.

i don't follow your logic or conclusion/insinuation at all.

and you've made an awful-lot of assumptions strictly from a photo. this happens often when viewing photos of recording studios and mix rooms, where people criticize the plants on the loudspeakers, bookshelves mounted horizontally and sitting on the bridge - all not knowing that in many cases, things were arranged at the behest of the photo-op, and as such is not the room configuration when critical work/listening is being done.

unless you can tell me what the room's design requirements are, and if/when visual preference trumped acoustical reponse, etc- then you are just making assumptions and then being critical based on those assumptions alone.

user could have had floor treatments installed and perhaps didn't perceive much of an acoustical difference - and thus decided to remove to maintain more pleasing visual appearance within the space while listening. that or, the floor treatments could be moved/positioned into place when doing critical-listening, and the user didn't want said treatments in place when the room was staged for a photo-op. who knows.
 

Dialectic

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Well, OK, but ... have you been experimenting during lockdown? Did you take out your pad, carpet and shag rug, in order to compare bare -vs- treated? Or perhaps overlay some reflective sheet material, just for a day? The Fraunhofer Institute did such experiments, and found the removal of floor reflections to be negative and unnatural sounding. Toole and Linkwitz found the presence or absence of floor reflections to have no net effect.

I'm all for skepticism and clean-sheet thinking, but it sounds to me as if your wife likes pad, carpet and rugs, and you've decided to make a virtue out of necessity, science be damned.
Yes, I've experimented and measured extensively. Early sidewall reflections are the most harmful to proper imaging, but the effects of floor bounce are measurable and audible. Some diffuse reflections are desirable with systems that lack crosstalk cancellation and other forms of DSP, but early reflections, including floor bounce, come at a cost with respect to imaging. When one listens with DSP that can deliver highly specific imaging, such as BACCH, the harmful effect of early reflections becomes more obvious.

you insinuated that the room is "incompetently treated", distinguished it from those that are (apparently) "properly conceived and executed" (and other form of tirade); attacking the room all because the floor was not adequately treated to your liking.

i don't follow your logic or conclusion/insinuation at all.

and you've made an awful-lot of assumptions strictly from a photo. this happens often when viewing photos of recording studios and mix rooms, where people criticize the plants on the loudspeakers, bookshelves mounted horizontally and sitting on the bridge - all not knowing that in many cases, things were arranged at the behest of the photo-op, and as such is not the room configuration when critical work/listening is being done.

unless you can tell me what the room's design requirements are, and if/when visual preference trumped acoustical reponse, etc- then you are just making assumptions and then being critical based on those assumptions alone.

user could have had floor treatments installed and perhaps didn't perceive much of an acoustical difference - and thus decided to remove to maintain more pleasing visual appearance within the space while listening. that or, the floor treatments could be moved/positioned into place when doing critical-listening, and the user didn't want said treatments in place when the room was staged for a photo-op. who knows.
I suspect--actually, I know--that requirements other than acoustic requirements were paramount in designing this room or staging these photos. If visual appeal trumps room acoustics, that's fine, but we are not on the interior design forum. (Do interior designers have web forums?)

There are likely basic problems in the selection of equipment in this very fancy system as well (some of the equipment, however, including the speakers, is very good), but we will not go into those.

Criticisms aren't tirades, and absence of evidence is not evidence of absence.
 
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onion

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Eliminating first reflections makes BACCH work better (including the floor reflections). Some recommend not 'overtreating' first reflections as this may take away too much energy, deaden the sound and lose the natural reverb of the room/ hall where the recording was made. With BACCH, that is not the case - eliminating first reflections actually restores the room reverb of the original recording.
 

Inner Space

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... absence of evidence is not evidence of absence.

But evidence isn't absent. Fraunhofer, Toole and Linkwitz have published evidence. You're disagreeing with it. Which is great - maybe we're making progress! But I think it's incumbent on you to publish too. Your extensive measurements would be a good place to start. Plus details of the controls, methodology, and participants, etc.

I'm sure if I said, for instance, "When I am told (ad nauseam at this point) that there is no evidence that boutique cables matter, I don't erroneously conclude that boutique cables don't matter," you would want me to show my working, right?
 

pozz

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because the rooms are typically designed such that a large mix board/console/desk/work-surface sufficiently blocks the floor reflection. a bit of a critical element of context to leave out regarding your statement above.
It is left in for the reverberance.

A floor reflection introduced in an anechoic setting creates large nulls which are filled in a regular room by other reflections. The floor (read: ground) is also the only surface which is more or less constant in our day-to-day lives so we likely are used to ignoring its effects.
 
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Inner Space

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In my setup, as in most, early reflections are noticeable and harmful to stereo imaging, and, as in most other home systems, the earliest reflections in my listening room come from the floor. Thus, if we care about sound and not about a photo op, we should probably do something to address those reflections.

Honestly, yeah ... intuitively I can't disagree with you. But what confounds me is that I have built three serious rooms (two "public facing" listening lounges for studio complexes, and one for myself at home) and whereas floor bounce was measurable and marginally audible in all three cases, the sounds of the rooms were universally preferred with floor bounce, not without. I agree with you (whisper it quietly) that Toole's stuff ain't necessarily the tablets of Moses, but his conclusion here matches mine. I suspect there's a fundamental DNA-level divide between listeners who prefer dead (or dead-ish) rooms, and those who prefer live (or live-ish). I'm in the latter camp, with, I suspect, the majority. I wish research would focus on the why of that, not just the what.
 

localhost128

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It is left in for the reverberance.

the reflective floor and front wall of an NE room strategically exist to provide a sense of room (ie, non-anechoic space) as experienced from the listening/mix position, while the speaker-listener response remains effectively anechoic. it allows for reflected energy within the room due to user interactions or discussion, but is not incident of significant energy radiated from the loudspeaker. it exists for "user comfort".

more modern Front to Back rooms (FTB: Northward) take a similar approach.

A floor reflection introduced in an anechoic setting creates large nulls which are filled in a regular room by other reflections. The floor (read: ground) is also the only surface which is more or less constant in our day-to-day lives so we likely are used to ignoring its effects.

the reply to your original statement was to clarify that while Non-Environment rooms do have a reflected floor, the floor reflection is typically attenuated by nature of blocking by the mix board/console/desk. context is key.
 

keenly

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No, you're right.

I chose 100Hz to compare the results with the T100. GIK haven't posted the RAL reports for the T70 or T40, which are tuned lower, so I couldn't make a fair comparison at those frequencies. The effective Q of these units is pretty narrow.

It terms of cost I could buy four T40s for every ACDA-10.

Again, sub-100Hz results are generally unreliable, and despite all the technical claims the full ACDA-10 report was never made available. Or even something simpler like in-room measurements. They have a dedicated listening room—they could easily post pics and REW results for that.

Acoustic geometry
Tested in the most reliable way possible?
 

pozz

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Acoustic geometry
Tested in the most reliable way possible?
The designer follows good principles, but the prices are high and no testing data is posted as far as I can see.

We tested the CornerSorbers at NWAA Labs because their test chamber is the largest in the U.S., and accurately measures absorption down to 40Hz (per ASTM C423-09a
It's a shame they don't post the results. Would go some way towards justifying the asking price. Although I'm sure the $10k they want for their 12 pack is nowhere close to justifiable.
 

keenly

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The designer follows good principles, but the prices are high and no testing data is posted as far as I can see.

It's a shame they don't post the results. Would go some way towards justifying the asking price. Although I'm sure the $10k they want for their 12 pack is nowhere close to justifiable.
Same as RPG, no results posted. It really pisses me off that all these brands have claims but no proof.
 

pozz

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Same as RPG, no results posted. It really pisses me off that all these brands have claims but no proof.
RPG does post results: https://www.rpgacoustic.com/modffusor/ Look under technical data. It's not super detailed, though, but way better than what you can get elsewhere.

RPG is expensive but their products are backed by good science.
 

keenly

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The designer follows good principles, but the prices are high and no testing data is posted as far as I can see.

It's a shame they don't post the results. Would go some way towards justifying the asking price. Although I'm sure the $10k they want for their 12 pack is nowhere close to justifiable.
what about
The BF-1200 Corner Bass Trap is designed for ultimate control of frequencies below 100hz in professional recording studios & hi-end hi-fi listening rooms.

Offering genuine bass control to 30hz, the BF-1200 is a serious device for rooms that need to sound seriously tight, precise and punchy in the bass frequencies.

 

pozz

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what about
The BF-1200 Corner Bass Trap is designed for ultimate control of frequencies below 100hz in professional recording studios & hi-end hi-fi listening rooms.

Offering genuine bass control to 30hz, the BF-1200 is a serious device for rooms that need to sound seriously tight, precise and punchy in the bass frequencies.

It's huge, so even if it was all porous stuff inside it would have an effect. Based on the description I think it's a frame with porous filling.

I don't think they have independent lab data. Price isn't high either. GBP 215 each for the largest.
 

pozz

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Didn't Toole recommend a specific RPG diffuser based on testing?
If he did I haven't seen it. RPG is pretty much industry standard because they invented a lot of the treatments and underlying rationale.
 

keenly

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If he did I haven't seen it. RPG is pretty much industry standard because they invented a lot of the treatments and underlying rationale.
In his book he mentions RPG diffusion.
 

pozz

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