I've talked to some people that have experience with acoustic engineering and they haven't been able to apply any logical physics behind the claim that they would work. They have simply shrugged their shoulders and pointed me in the direction of proven, measured, tested technology that is undeniably effective forms of room treatment. In the realm of acoustic treatment, which is how they are marketed, there are three things that happen to sound waves. 1. Reflection 2. Absorption and 3. Diffusion
I don't know what those HFT are going to do with either three of those things that do anything to a sound wave. Even the physical size would dictate that they aren't large enough of an object to do anything that one can actually hear in terms of "room treatment". There are measurement equipment and things that can be done to see the effects of any room treatment products, or even arranging the speakers in a different position, or using things like furniture, drapes, etc. in the room which will do any of those three things. Drapes absorb certain frequencies which can be measured and can effect reelection of certain frequencies, Couches, chairs, etc. can do the same thing. Etc. etc. But it's a matter of their effectiveness. They probably won't do as much as designed and tested forms of "room treatment", but it's OK to use drapes, couches, chairs because they are large enough objects to absorb sound. Heck, even out bodies will absorb sound, which is why a room packed with people is going to change the acoustics of a room that is empty. But little tiny pieces of metal? No one has shown any room measurements to prove otherwise, which SHOULD be done. I haven't read any university study on them, I have seen no acoustic engineer show room measurements to prove they actually do anything. Now, with a device you plug into the wall? I'm sure that it might do something at some level to the performance of other equipment since there are plenty of parallel filtering products on the market that can reduce noise, which I'm sure effect what's comes out of the speakers, but to think it's a form of "room treatment", I think that's stretching it. There are plenty of ways room acoustics can be measured as there are several pieces of s/w and h/w that can be used to test the "THEORY" that they work. I think it's in EVERYONE'S interest to ask the mfg to show independent test results from SOMEONE, whether it's an acoustic engineer applying what is commonly taught on what measurements to take and compare an untreated room with a treated room to see how they are or aren't changing the room acoustics FIRST before just simply saying they do anything. Yeah, I'm sure people can be manipulated into thinking they are hearing something different. I would THINK that the FEQ might do the most, but I don't think it's going to be more effective than putting some absorption panels and diffusion panels in strategic locations in the room. I've heard the effects and seen measurements of an untreated room vs a treated room using things on the market that have been sold for many years. Some are just more or less effective than others. But there are plenty of measurements that can be taken to prove their effectiveness. But, I think it's futile to argue this without measurements. We can see measurements of anything else that's connected to our system or placed in our rooms to see if there is a difference in quality of sound, so what makes this product immune to such measurements? I have yet to talk to someone with experience in designing room treatment, designing rooms for listening/recording purposes or fine tuning rooms that have taken measurements and have come forward with them to support the use of these devices. I would look towards someone that has credentials in the industry, University test results, or some form of independent study proving their effectiveness and actually comparing it to something that HAS been proven. $1000 to $1500 in absorption panels and diffusors WILL make a NOTICEABLE improvement if placed in the right places (just simply 1st wall reflections) will make a considerable improvement, and it doesn't take that much of it. So why would people spend the same amount of money on something that hasn't been proven over things that have? I'm STILL trying to figure that one out. This isn't a thing of "you have to hear them", it's just trying to add some logical reasoning by wanting to see before and after room measurements to actually prove they work and to prove that they work better than the same amount of money spent on something that IS proven to work. Absorption panels cost less than a few hundred dollars each, depending on things like fabric used or not used. Diffusors can cost a few hundred bucks each depending on size and construction materials. $1500 +tax actually goes a long way if you buy the right products that will increase the sound quality of our equipment in most small rooms. Obviously, low frequency absorption products are more expensive, regardless of the product, and it takes quite a bit since low frequencies are not so simple to absorb, but for the majority of the bandwidth we are listening to (midrange and upper frequencies), $1500 of room treatment will make a very significant night/day improvement. Obviously, one can spent tens of thousands of dollars, to get the ultimate listening room, but there really is no comparison between using a few sets of HFT's and a FEQ and a totally perfectly designed and tuned and sound proofed listening room. It's just a shame people aren't asking the mfg to show some independent test results on the effectiveness of room acoustics. Ways to spend money on "tweaks" isn't a new concept. I think a lot of us are trying to find that weird product that's unexplainable to improve our system, but unfortunately, we should still be measuring the effects of it to produce undeniable results to prevent any arguments.
As far as measuring something, it doesn't change the outcome, it just proves whether something works or doesn't. It just a matter of conducting the right tests with the right equipment that's capable of measuring something to prove or disprove the effectiveness of the product in question. Listening is something that is a perfect ability of ours, because no two people hear the same, and our brains (whether or not we are under the influence of mind altering chemicals) can play tricks on us. Pyschoacoustics and optical illusions have taught us that. It's easy to produce scenarios where we think something is happening, when in reality it isn't.
Apply some common sense before spending money, unless you just like to buy things whether they work or not. I'm sure we're all guilty of that from time to time.
I would spend more time studying real forms of room treatment and spend your money in that direction because you'll actually HEAR noticeable improvements that can be measured if you buy a product and place it in the room which the mfg can help you with that, and that's been studied and measured to the point where it's almost to a point where it's common sense and it WILL make a big difference in sound quality and they can show measurements to back up their claims, if they can't then move on to someone that can.