Does anyone here have experience with acousticfields.com or with true pressure traps?

Crossram

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I am preparing to build a two channel listening room in my basement. Planned dimensions are 17’X23’X10’. Perfect chance to get it right since it is to be built from scratch. One chance if you will.

I have some experience with velocity traps (absorption), enough to know that when using typical absorption products, it is nearly impossible to effectively address room bass nodes without creating an acoustically dead room since fiberglass and rock wool traps are exceptionally efficient at absorbing mid and high frequencies and exceptionally inefficient at absorbing low and even mid-bass frequencies.

After checking out several companies online that specialize in room treatment, Acoustic Fields (acousticfields.com) stood out to me because they design and build pressure traps that precisely target specific frequencies (vs the broad-band behavior of velocity/absorptive traps) based on mathematical modeling identifying exactly where and what frequencies of acoustic anomalies will occur in a specific room and matching frequency-specific pressure traps in the exact room locations that reduce/eliminate problem nodes at the listening position without affecting non-target frequencies as velocity/absorptive traps do.

This approach promises to get quite expensive. I am wondering if anyone here has any experience with Acoustic Fields (or installing/using pressure traps) that would provide helpful input regarding their experiences.
 

Mike Lavigne

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i met Dennis 10 years ago, and i do think his views on acoustics are valid. but as you can read below, his customers don't appear to be satisfied, especially in the ROI and timely follow-thru parts. so be careful.

i am not his customer, but did hear his own room 10 years ago (in Phoenix) and was impressed.


 
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MarkusBarkus

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...@Crossram I have several velocity and pressure traps in my basement audio room. Some are DIY from plans (including from Acoustic Fields), others were commercially built/purchased. Primacoustic and GIK Acoustic. Overall, I find the result satisfying. I need to test it, and recently purchased that Umik2 mic and downloaded REW software.

My strongest recommendation to you is to do a quick search here for AcousticFields and/or the owner to inform your decision.

If you are building walls from scratch, I think a constrained layer wallboard technique would be a great approach to consider.

Also, Norman at AVRoomservice seems very knowledgeable and responsive

I use their isolation footers to good end. I like their concept of building traps onto/in the walls, and using fabric to cover the devices. That approach seems highly customizable, to me.

But you are right, some calculations and measurements would be a scientific, sensible approach. BTW, GIK has bass traps tuned to various frequencies, for another example.

I think this depends on budget and how kooky you want to get! I have treatments, seen and unseen, in multiple places. And constrained layer walls. And DIY can be excellent, BTW. The quads and 165lb. trap were build here, by me, from plans. Exciting project! Have fun.
 

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Crossram

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A very sincere thank you to Mike Lavigne and to MarkusBarkus for the immediate and helpful responses. I read through the thread Mike provided and there are some obvious reasons for concern.

MarkusBarcus, I will contact Norman and see what he has to say about my project.

Again, please accept my sincere gratitude for both of your responses. I will keep you informed as my project progresses.

David
 
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HughP3

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A very sincere thank you to Mike Lavigne and to MarkusBarkus for the immediate and helpful responses. I read through the thread Mike provided and there are some obvious reasons for concern.

MarkusBarcus, I will contact Norman and see what he has to say about my project.

Again, please accept my sincere gratitude for both of your responses. I will keep you informed as my project progresses.

David
David, you have likely viewed a video featuring my room on AcousticFields web site. While i am very happy with the outcome, having seen recent information concerning Dennis i cannot recommended him in good conscience until he rights the ship.

My build thread called the Big Dig on WB describes in detail the room build where most of it i did myself. There is a lot of good info there. He did provide very good qrd diffusures but i gather i was a bit lucky as that was before these new issues.


In addition here is a link to a academic study concerning activated carbon as bass traps. The room is so important! Good luck to you.

 
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Cellcbern

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I am preparing to build a two channel listening room in my basement. Planned dimensions are 17’X23’X10’. Perfect chance to get it right since it is to be built from scratch. One chance if you will.

I have some experience with velocity traps (absorption), enough to know that when using typical absorption products, it is nearly impossible to effectively address room bass nodes without creating an acoustically dead room since fiberglass and rock wool traps are exceptionally efficient at absorbing mid and high frequencies and exceptionally inefficient at absorbing low and even mid-bass frequencies.

After checking out several companies online that specialize in room treatment, Acoustic Fields (acousticfields.com) stood out to me because they design and build pressure traps that precisely target specific frequencies (vs the broad-band behavior of velocity/absorptive traps) based on mathematical modeling identifying exactly where and what frequencies of acoustic anomalies will occur in a specific room and matching frequency-specific pressure traps in the exact room locations that reduce/eliminate problem nodes at the listening position without affecting non-target frequencies as velocity/absorptive traps do.

This approach promises to get quite expensive. I am wondering if anyone here has any experience with Acoustic Fields (or installing/using pressure traps) that would provide helpful input regarding their experiences.
Suggest you also take a look at DHDI whose ZR Acoustics panels have been dramatically better in my listening room than conventional absorbers and diffusers:


 

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MarkusBarkus

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David, you have likely viewed a video featuring my room on AcousticFields web site. While i am very happy with the outcome, having seen recent information concerning Dennis i cannot recommended him in good conscience until he rights the ship.

My build thread called the Big Dig on WB describes in detail the room build where most of it i did myself. There is a lot of good info there. He did provide very good qrd diffusures but i gather i was a bit lucky as that was before these new issues.


In addition here is a link to a academic study concerning activated carbon as bass traps. The room is so important! Good luck to you.

Hi Hugh. I recall reading about your project when the marketing email arrived linking to your project. Very nice project! It must sound excellent.

I read the paper you kindly provided back when I was looking into solutions, and I think carbon pellets do have merit. The caveats are: the material is very heavy, and most widely available in small amounts (for water filtration).

I did find a large-scale wholesale place, but we played phone tag a bit, and life moved on.

In my research/IMO, I do not find what AF offers to "license" customers to be any different than what is widely available in the marketplace. I expect the license is a way to extract a bit more money from clients, and to add a little faux-proprietary mystery. But at least it works.

I bought a bundled set of plans from AF which was the best value on the website. I know my way around a table-saw, and have all the relevant tools to build a professional product.

The savings on shipping alone was huge. I think I built the two quads for 300 bucks. 25 for all the plans. The giant bass trap was about 200 bucks or so.

It is serious DIY level project work, but it is possible to do. I enjoyed reading about and seeing your room, Hugh. Cheers...
 

Crossram

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Dec 18, 2013
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Thank you Hugh and Cellcbern and (again) MarkusBarkus for your helpful replies. I participated in a call with Dennis @acousticfields.com this afternoon as I had already scheduled it and wanted to hear what he had to say. He was friendly and helpful and came across to me as one who knows what he is talking about. The bottom line is that he offered his room design services for a substantial fee (which is completely credited toward a subsequent purchase of goods) and suggested that I go the DIY route, buying only the carbon and foam from him, due to my limited budget. It appears it will take a lot of carbon to build the complement of pressure traps (around 70!) needed to completely treat a room this size (17’X23’X10.5’).

Aside from the concerns expressed earlier, two things look to be a problem: 1) he said he is backlogged 2-3 months for design services and 2) the cost. I could possibly swing (at the high side of my budget) the number he quoted if the pressure traps were turnkey, but adding labor (and the cost of wood) for my carpenter to build 70 of the pressure traps would make the cost way beyond my means.

Hugh, I will study the documentation of your project. Thank you for bringing it to my attention. Cellcbern, I will check out DRDI and their ZR Acoustics products as well.
 
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Carlos269

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Thank you Hugh and Cellcbern and (again) MarkusBarkus for your helpful replies. I participated in a call with Dennis @acousticfields.com this afternoon as I had already scheduled it and wanted to hear what he had to say. He was friendly and helpful and came across to me as one who knows what he is talking about. The bottom line is that he offered his room design services for a substantial fee (which is completely credited toward a subsequent purchase of goods) and suggested that I go the DIY route, buying only the carbon and foam from him, due to my limited budget. It appears it will take a lot of carbon to build the complement of pressure traps (around 70!) needed to completely treat a room this size (17’X23’X10.5’).

Aside from the concerns expressed earlier, two things look to be a problem: 1) he said he is backlogged 2-3 months for design services and 2) the cost. I could possibly swing (at the high side of my budget) the number he quoted if the pressure traps were turnkey, but adding labor (and the cost of wood) for my carpenter to build 70 of the pressure traps would make the cost way beyond my means.

Hugh, I will study the documentation of your project. Thank you for bringing it to my attention. Cellcbern, I will check out DRDI and their ZR Acoustics products as well.

I caution you to do your research before you commit to the use of these tube traps. I personally would recommend the use of judicially applied diffusion and diffraction panels as opposed to these absorption panels. Without performing proper measurements before and during the course of the installation, you could adversely effect the acoustics of your room with these bass trap absorption panels. A dead room is no better than a reverberant room. Once you commit to extensive absorption the way Hugh did, there is no flexibility for boundary reinforcement, and you will be relegated to the use of active bass, like Hugh does with his Gryphon bass towers.

Too much of a good thing is not a good thing, specially when not applied properly.
 

HughP3

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Hi Hugh. I recall reading about your project when the marketing email arrived linking to your project. Very nice project! It must sound excellent.

I read the paper you kindly provided back when I was looking into solutions, and I think carbon pellets do have merit. The caveats are: the material is very heavy, and most widely available in small amounts (for water filtration).

I did find a large-scale wholesale place, but we played phone tag a bit, and life moved on.

In my research/IMO, I do not find what AF offers to "license" customers to be any different than what is widely available in the marketplace. I expect the license is a way to extract a bit more money from clients, and to add a little faux-proprietary mystery. But at least it works.

I bought a bundled set of plans from AF which was the best value on the website. I know my way around a table-saw, and have all the relevant tools to build a professional product.

The savings on shipping alone was huge. I think I built the two quads for 300 bucks. 25 for all the plans. The giant bass trap was about 200 bucks or so.

It is serious DIY level project work, but it is possible to do. I enjoyed reading about and seeing your room, Hugh. Cheers...
Thank you. Your room looks great, nice job on the qrd. They are not easy to build so yes you've got way more wood working skills than i!!
 

HughP3

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Thank you Hugh and Cellcbern and (again) MarkusBarkus for your helpful replies. I participated in a call with Dennis @acousticfields.com this afternoon as I had already scheduled it and wanted to hear what he had to say. He was friendly and helpful and came across to me as one who knows what he is talking about. The bottom line is that he offered his room design services for a substantial fee (which is completely credited toward a subsequent purchase of goods) and suggested that I go the DIY route, buying only the carbon and foam from him, due to my limited budget. It appears it will take a lot of carbon to build the complement of pressure traps (around 70!) needed to completely treat a room this size (17’X23’X10.5’).

Aside from the concerns expressed earlier, two things look to be a problem: 1) he said he is backlogged 2-3 months for design services and 2) the cost. I could possibly swing (at the high side of my budget) the number he quoted if the pressure traps were turnkey, but adding labor (and the cost of wood) for my carpenter to build 70 of the pressure traps would make the cost way beyond my means.

Hugh, I will study the documentation of your project. Thank you for bringing it to my attention. Cellcbern, I will check out DRDI and their ZR Acoustics products as well.
Yes the carbon alone is expensive per pound and all the walls and ceiling would take a lot. The qrd he built for me are very well made (all cnc) but very expensive. I dont have the skills to make them. He uses some type of ray trace acoustic sofware which one can simulate various acoustic layers strategies. He is very convincing and my room imho does sound very good. But the other stuff going on is concerning. Hope you find a comfortable path forward.
 

Crossram

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Thank you Hugh. I reviewed your entire thread on your room build and was quite awed by it. Spectacular to say the least!

Did you do any acoustical room measurement after you completed the room?
 

HughP3

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Thank you Hugh. I reviewed your entire thread on your room build and was quite awed by it. Spectacular to say the least!

Did you do any acoustical room measurement after you completed the room?
I have done my last speaker move using the master Jim Smith. Speakers are now almost mid room. Will be doing some measuring in a month or so once i get back from traveling. Jim was very happy with his ears only. Bass is very controlled and he Especially liked the sound stage, separation and decay. I do know that 25 hertz is muted somewhat but 20 hertz is audible. Should be interesting but what will be even more so will be the comments that are sure to come :)
 

ACHiPo

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I have done my last speaker move using the master Jim Smith. Speakers are now almost mid room. Will be doing some measuring in a month or so once i get back from traveling. Jim was very happy with his ears only. Bass is very controlled and he Especially liked the sound stage, separation and decay. I do know that 25 hertz is muted somewhat but 20 hertz is audible. Should be interesting but what will be even more so will be the comments that are sure to come :)
Wish Jim was closer to CA!
 
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Brucemck2

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At a substantially higher price point, Keith Yates does really impressive work. In my room he spec’d a wide array of RPG products for the walls and ceilings, and, modeled alternative locations (and gains and delays) for placing five subwoofers.
 

Crossram

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Thanks for the recommendation Brucemk2. Has anyone had any experience with rectangular rooms built with non-parallel walls or sloping ceilings? Is there a benefit to either?
 

MarkusBarkus

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@Crossram I think there is a benefit to having non-parallel walls or ceilings, although I guess sloping the floor would have some potential downsides in a home.

Although I cannot provide the mathematical proofs, I think non-parallel surfaces act more like diffusors or reflectors that reduce destructive/reinforcing wave interactions (although over-all sound pressure could still be a concern to be managed).

Here is a photo I took last night. Hatch Hall was purpose built at the Eastman complex; it is one of three main facilities there.

This won't be news to you or anyone else, but many music halls have angled walls (and often sloping floors too). You cannot see it well, but this room also has highly baffled side-walls. IIRC they are tunable.
53E23EA4-7567-4B00-AA4A-2E03879390B4.jpeg

I was thinking last night how interesting it was that the front/stage is so highly reflective sonically, when home listeners often deaden the front wall, although I suppose that is an on-going debate: live end/dead end. And musicians need to cast their sound out to an audience, without volume controls our amps provide.

I have tried adsorption and diffusion on the front wall, and a combination sounds best. I have multiple bass traps there, but I put diffusors in front of the traps. Those bass wave forms are huge and very powerful: we are not stopping those babies when they get going (think trash-truck rumblings or trains if you live near one).

I mentioned my room is highly treated, which I did a bit at a time, listening along the way. If I had the capability at the time, I would have measured the room along the way for a more scientific approach.

I live in a condo complex which is built in an arc, so one side of the home has a 23 degree angled wall on three floors and the basement, of course.

I worried about the asymmetry of my room (and had I listened to Dennis F. I would have abandoned audio altogether. He essentially said my room was junk), but it's what I had, so...

The walls have "Z" clip rails across the studs. This is a basement, BTW. Homesote is screwed to the metal strips. A thin layer of pliable adhesive was applied to the homesote, and drywall screwed down to that in the usual manner. I believe this concept to be valid, but it was done with the materials and knowledge of the day (25 yrs ago?).

My various treatments were added many years later, piecemeal. I think the sound is very well managed in the room, although at just under 8' I long for a taller room.

Although you can get an over-all plan for your space, IMO you are first dealing with your walls and ceiling structures. That stuff you can't really change post-build. Problem areas can be managed along the way, although some of them can be predicted to be problematic (corners, for example).

One of the key elements, IMO is where your gear will live, and your listening position. Will you be near or far from the speakers?

Although I read until my eyes watered and considered many things, it wasn't until I put my speakers into my intended location that I found a real problem: Who stole my bass?

It turned out my listening position was essentially in a null-location, low frequency waves cancelling each other out. Highly practical lesson in the physics of waves! I was crushed.

I had to change everything, moving and listening over time. My speakers are much further from the front wall, and I am now about 9' away. That seems the best balance for detail, soundstage and overall presentation.

OK, well sorry to blather on with a long reply to your very concise question about non-parallel room planes. I think they could be helpful to consider modeling, if you can manage it in the build phase, budget, etc. as a room-within-a-room.
 

ACHiPo

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@Crossram I think there is a benefit to having non-parallel walls or ceilings, although I guess sloping the floor would have some potential downsides in a home.

Although I cannot provide the mathematical proofs, I think non-parallel surfaces act more like diffusors or reflectors that reduce destructive/reinforcing wave interactions (although over-all sound pressure could still be a concern to be managed).

Here is a photo I took last night. Hatch Hall was purpose built at the Eastman complex; it is one of three main facilities there.

This won't be news to you or anyone else, but many music halls have angled walls (and often sloping floors too). You cannot see it well, but this room also has highly baffled side-walls. IIRC they are tunable.


I worried about the asymmetry of my room (and had I listened to Dennis F. I would have abandoned audio altogether. He essentially said my room was junk), but it's what I had, so...
I think symmetry and square walls makes things more predictable and treatable for us mere mortals and for a relatively small sweet spot unlike theaters which need to provide a uniformly good experience for all seats.

Dennis F told me the same thing about my room. One of several reasons our relationship didn’t go beyond that first call.

I am curious how Dennis’ “room in room” at PNW Audio show sounded—I haven’t read or heard much one way or another.
 

Cellcbern

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Based on what I’ve read and the experts I’ve talked to there is no benefit to angled and non-parallel walls in a listening room or pro studio (which are different from a concert hall) and they don’t obviate the need for room treatments. Far as I can tell they are not currently used in recording studios and mastering labs, nor in the demo/listening rooms of premier high end component manufacturers and dealers.
 

MarkusBarkus

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...if I was starting a project room from scratch, I would at least want to have the discussion re: non-parallel surfaces vs. right-angled design.

The open question for me: Do we build for audio at right angles because it's cheaper, or because it's better for audio?

Even *if* one found "angled" walls were technically better, budget or acceptance by non-audio audience members might still dictate a traditional build.

We're just spit-balling here, so everything is on the table, theoretically, IMO.
 

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