Different Types of Acoustic Foam
Smooth
This is one of the less frequently used acoustic foam options. The reason it is seldom used is because sound travels in waves and is better absorbed by foam with raised elements. In fact, with smooth panels of foam, sound can actually be reflected rather than absorbed. Smooth surface foam panels can still be useful to achieving your sound quality goals. It can be used as a foundation layer underneath textured panels for added sound proofing.
Wedge
Offering a cool, spiked look that makes it popular for those looking for an edgy appearance to add to their space, wedge acoustic foam absorbs sound waves efficiently thanks to the design. While this option for acoustic foam is effective, it is somewhat limited when it comes to the direction of the sound. This can make is less than ideal for larger spaces. Choosing large wedges will improve the overall sound absorbing abilities of this shape, but the directional element can make it a deal breaker for some consumers.
Eggcrate
With a rounded end instead of the sharp point of wedges or pyramids, eggcrate foam is one of the most affordable solutions for your soundproofing needs. Many professionals choose to pair this foam with other solutions such as acoustic cloth for an even better result. However, this solution works fine on its own for a DIY project or for a studio on a budget.
Pyramid
Similar to wedge, but with a pointed tip, this is a reliable option for acoustic foam with a few special considerations. While it offers dependable sound absorption comparative to other options, pyramid shaped foam tends to have a lowered rate of absorbing lower frequencies in comparison to other types. This isn't to say this type of foam can't be a viable option for certain spaces and purposes, but it is a consideration to keep in mind. There are ways of offsetting this issue with the use of corner block absorbers to pick up any low frequencies left over from the acoustic foam.
Spade
With its less pronounced design and flatter layout, spade foam offers an attractive solution similar to smooth panels with better sound quality properties. It is adept at absorbing sound waves of various frequencies for a reliable option. While this option offers better sound quality performance than smooth textures, it should be noted that it is less effective than options such as pyramid or wedge. A variation of spade shape is wave shape. It is essentially the same in function and performance, but with a more curved surface design which gives different sound quality to a space. Many people choose to use both shapes in the same space to achieve a pleasing look with a more varied sound quality.
Grid
Another option with a less pronounced style, grid acoustic foam uses raised lines within the surface to redirect and absorb sound waves, vibrations, and diffuse feedback. It is often chosen more for the appearance factor than performance, but that is not to say it doesn't have great performance aspects. This type of foam can be well-suited to smaller areas without many multi-directional frequencies as opposed to straight on frequencies in the direction of the foam.
So, which type of foam is the best? It is impossible to say one type of foam is the superior option. Since the factors affecting sound quality are dependent on the location, the type of foam used, and other external influences, the best bet is to look at your situation individually. For instance, an L shaped space will need different acoustic foam considerations than a room in a square shape since room shape plays a role in the way sound frequencies travel. In fact, for most locations, the best solution is to combine the different types of acoustic foam to get the best results. When comparing foam, it's also important to know how our foam stacks up against the competition in terms of overall value.