I have always been a staunch advocate of adding room acoustic devices as an integral part of any high quality sound system. That is unless you listen within an anechoic chamber or a padded cell. There are many different ways to handle standing waves whether it is DSP, diffusion, wide spectrum, or narrow spectrum absorption. GIK 4A Alpha Panel Diffusors are a great way to improve your listening room and here's why: Two of the most important elements in creating the foundation of any great listening room are choosing a world class speaker and an acoustic treatment plan that tames any anomalies in your room of choice. I have used a blend primarily absorption with limited diffusion in my space for many years by using four GIK 244 Bass traps to deal with the rear wave from my speakers. In addition, they are either in two corners that tend to store a lot of energy or at first reflection point on the side walls (when I have my system setup along the short wall of my room.)
I had opportunity to have some time with GIK's new 4A Alpha Panel diffusors for those that want to add some basic absorption and diffusion into a room without committing the time, resources, and wall space to a deep quadratic diffusion array and larger absorptions panels. The GIK 4A panels are a great start. In some less lively rooms, these may be all you need at the first and second reflection points. The 4A Alpha panels feature a 0.25” thick Maximum Length Sequence diffusors to scatter sound waves down to 1000Hz to tame reflection in the treble range, on top of a panel with an absorption coefficient that peaks a 1.3 at 400Hz with a slope to .65 at 5kHz. This is a great starter kit for anyone looking to deal with the typical acoustic problems of a suburban home with too many reflective surfaces (windows, mirrors, pictures) and excess energy being reflected. These reflections are from the front wall, first and second reflection points (walls and ceiling) that muck up the soundstage with out-of-phase acoustic information (otherwise known as distortion). Not that this single kit of four panels would completely treat a room, yet for only $340 you get four 24”x24” panels that are perfect for treating either first or second reflection points. They can also dampen the reflections in the front of the soundstage. If you only had one kit you could use it to do both, but I would get two kits and put four panels in front and four panels on the side walls. Depending on how much energy storage you are getting on your front wall, you may want to use something more like the GIK 244s. The 4A Alpha panel really shines as a simple, low profile, and elegant way to deal with first and second reflections on the sidewalls. The diffusion isn't as elaborate as some quadratic diffusors, but is perfect at diffusing the critical treble at those pesky first reflections. Aside from bass modes this can be some of the most distracting distortion characteristics in a room so very important to deal with.
Sound Improvements With GIK
The impressions were mixed, taking into account my room is already quite well treated the differences were subtle. I found the strength of the 4A panel was as a world-class treatment for the first reflection points. The addition of attenuation of the high frequencies through the diffusor along with sufficient absorption in the mid bass and slightly less attenuation in the low bass frequencies provided a little bit of extra liveliness in my room and the additional bass also provided grounding for the soundstage giving the perception of a wider soundstage. As a means to deal with the energy in your front soundstage, for which I was originally using a pair of GIK 244 Bass traps, the 4A does not really absorb enough energy. They are far better than no panels at all for the front stage but you don't really take advantage of the diffusion since treble behaves more linearly and the port doesn't typically produce any frequencies in the effective diffusion range of these panels so you would probably be better off with something that is more devoted to absorption in the front part of a system. The GIK 4A does provide a good level of absorption just not as much as some panels available from GIK and others. Typically there is a lot of extra energy in the front of you system from port noise and the back wave of the speakers can cause a lot of distortion and generally muddle your sound stage. If your front sounds stage is wide or if you speakers are a long way off the wall with taller ceilings, the 4A may be sufficient, they were slightly lacking in my room for this purpose.