Acoustic treatment question: do you agree with Dennis Foley that $46k to $65k is required?


In a video from 1/29/2021 (yesterday) Dennis Foley, Acoustic Fields warns people about acoustic treatment budgets. He asserts in this video that treatment will likely require (summing up the transcript):

Low end treatment: $5-10k

Middle-high frequency: $1-1.5k

Diffusion: Walls $10-15k, Ceiling: $30, 40, 50k

https://youtu.be/6YnBn1maTTM?t=160

Ostensibly, this is done in the spirit of educating people who think they can do treatment for less than this.

People here have warned about some of his advice. Is this more troubling information or is he on target?

For those here who have treated their rooms to their own satisfaction, what do you think of his numbers?


hilde45

Showing 5 responses by brownsfan

The problem with cost analysis comparisons from the various vendors is that the absolute cost is not very meaningful, within reason.  What one needs to focus on is the cost effectiveness of the various products.  That is not a simple matter of Sabins/dollar.  The traps don't sound the same.  I have a variety of products in my room.  I've got RealTraps Mondo traps, GIK soffit traps, Mega traps, 6 alphas, Tritraps, and a variety of the GIK 242 and 244 type traps.  Most of these traps are range limited in order to address LF ringing.   I get the best sound with my RealTraps (limp membrane type) mounted on the front walls, soffit traps in the front corners, Real Traps Mondo in the right rear corner, a GiK Tritrap in the left rear corner,  and GIK 6 alphas on the rear wall.  The LF traps are not interchangeable in terms of sound.  

I am a die hard advocate of using REW to make room treatment decisions, but I can't tease a rationale out of the measurement data to explain why a given low frequency trap sounds better than another in a given location. I made the decision to defer permanent installation of traps until I was finished.  So I can still switch out locations on most of my traps even now.

Most of us are not inclined to run A/B comparisons of different trap types in our own rooms.  The only reason why I did this is because I added my traps in 3 different phases and ended up with a bunch of different stuff.

Let me be clear-  There is a reason why I haven't bought any of Foley's products, and it is not because of their cost in absolute terms.  I don't know how much carbon are in his traps, but the activated carbon he uses runs from about $80-$200 per kilogram.  His traps aren't going to be nearly as easy to build as a GIK Monster trap.  I might suggest the price of his traps is reasonable based on what I think it would take to make them.  The key question is "Are they competitive on a cost/perfomance basis.   He doesn't make that argument, but rather makes an argument that you will die instantly from beta particles shooting out of the fiberglass.  Sorry, I ain't buying that snake oil.

I think the best approach for someone starting fresh in an untreated room is to take a somewhat theoretical approach.  Limp membrane traps have an inherent advantage for use in high pressure zones such as front walls and corners.  RealTraps, in my estimation, is the best source of limp membrane traps.  Backwalls, depending upon distance from the listening position, can benefit from a mixture of traditional absorption and diffusion.  I think this is why I had such good luck with GIK 6 alphas in that position.  I think that what works best for sidewall first reflection points is heavily dependent on the width of the room.  I would be reluctant to generalize on that.  I prefer to leave side walls forward of the first reflection points untreated, and use traditional fiberglass absorption behind the first reflection points. 

I didn't have a clue what I was doing when I started.  Somehow, by a mixture of hard work, aptitude for physical sciences, and dumb blind luck I took a room that was miserable and transformed it to one that was quite good.  I've got about 7K in the project including a Swarm sub system but not counting replacing my flooring at a cost of 3.5 K, which in my room, was absolutely necessary.  Spending 10K in anything like a normal room should be more than enough.   The hard part is learning enough so you can be smart about what you do. 


shalommorgan,  VERY impressive work and a really nice looking system.   In an earlier post, I mentioned that I found the carbon panels conceptually intriguing.  I did not realize one could purchase the plans and carbon from Foley to build the traps.  
Dennis Foley runs a business. He has a business model and a target demographic for his clientele.. My entire system, including room treatments, is under 50K. On the whole, my system/room is to my ears the best I have ever personally heard, and I’ve auditioned systems that retailed for over 200K in rooms that were well set up and treated. He has some products that are very intriguing. I don’t discount him as a complete quack. I don’t agree with everything he says, but that doesn’t make him a charlatan. There can be a number of effective solutions to any problem. Some are more efficient and cost effective than others.

GIK has a different model and different target clientele demographic than Foley does. They also have some worthwhile products, and I’ve got over 2K invested in GIK products.

RealTraps falls somewhere in between GIK and Foley models. Their limp membrane traps are very good, and I have about 1.5K invested in them. I wish I had used more of them and fewer of the velocity traps sold by GIK.

This stuff is not so much a buyer beware situation as it is a buyer be informed situation. These guys are going to sell you what they make. GIK won’t tell you when RealTraps makes a better product for your need.  The buyer has to figure that out himself.

Being ill informed and unwilling to learn about room acoustics and treatment designs is costly. As always, stupid is expensive.

I know from experience!
Not to derail the thread, but I too find Foley’s fiberglassophobia off putting and borderline ludicrous. Don’t get me started on perhaps well intentioned folks who invoke metaphysical concepts where they don’t belong, as seems to the the case in this instance. If it ain’t "all natural" or "organic" it is deadly, they seem to think. Never mind the fact that some of the most toxic substances known to man are natural products. Let’s go back to the good old preindustrial days, when people were really healthy as reflected in their average life span of 32 years.

OK, I will get off my soap box. All that said, Foley’s use of activated carbon (charcoal) is really intriguing. I can imagine those traps could be quite good. The ACDA 12 has some good activity below 50 Hz where it is hard to find things that work. They are very expensive and no doubt quite heavy, so are they cost effective? I don’t know.
audition_audio makes a great point here.  If you are talking 100K, you could build a pretty good room with optimal materials and dimensions.

That said, I'm not as sold on the non parallel surfaces concept as I used to be.   Non parallel surfaces will not eliminate modes, it will make the modes less predictable.  The existing models (that I know of) won't work on non parallel surfaces, which makes the room an expensive experiment.

I'd take a room that is roughly 23 x 16 x11 on a concrete slab with medium weight carpeting and go from there.   Use of a distributed bass array and judicious use of the right kind of treatments in the right locations and you would have a really good room pretty quickly.