Many of the audiophile racks use constrained layer shelving. I believe some of the the Grand Prix racks may use straight acrylic.
My only recommendation would be to incorporate the constrained layer principle into your shelving material. I've experimented with a number of shelf materials over the years: granite marble, glass (including very thick glass and security or laminated glass), corian, MDF, phenolic, maple etc.
On a budget I would recommend a constrained layer shelf consisting of two layers of baltic birch with a 1/8" piece of neoprene sheet between them. The neoprene sheeting would be available online or typically from an upholsterer. A single shelf would probably come in around $30-$40 in this configuration. I would vary the thickness of the baltic birch to accommodate the weight of individual components. Just thick enough to support the weight without any signs of buckling or sagging.
Spending a bit more, but probably still significantly less than 1 1/2" maple, you could use extruded acrylic as the top layer, followed by the neoprene sheeting with baltic birch on the bottom. Again, just thick enough in total to support the component with no sagging. This configuration will be more expensive due to the cost of the acrylic but really offers exceptional performance IMO. I use this under my table in an older Target Wall Mount and the combination was the best in my experience.
1 1/2" phenolic was probably a distant second in terms of sonics, is substantially heavier and also quite expensive.
My only recommendation would be to incorporate the constrained layer principle into your shelving material. I've experimented with a number of shelf materials over the years: granite marble, glass (including very thick glass and security or laminated glass), corian, MDF, phenolic, maple etc.
On a budget I would recommend a constrained layer shelf consisting of two layers of baltic birch with a 1/8" piece of neoprene sheet between them. The neoprene sheeting would be available online or typically from an upholsterer. A single shelf would probably come in around $30-$40 in this configuration. I would vary the thickness of the baltic birch to accommodate the weight of individual components. Just thick enough to support the weight without any signs of buckling or sagging.
Spending a bit more, but probably still significantly less than 1 1/2" maple, you could use extruded acrylic as the top layer, followed by the neoprene sheeting with baltic birch on the bottom. Again, just thick enough in total to support the component with no sagging. This configuration will be more expensive due to the cost of the acrylic but really offers exceptional performance IMO. I use this under my table in an older Target Wall Mount and the combination was the best in my experience.
1 1/2" phenolic was probably a distant second in terms of sonics, is substantially heavier and also quite expensive.