Aftermarket Audio     Thunder 4000 Series   |   Thunder 4500 Series   |   Thunder 6000 Series   |   Thunder 8000 Series   |   Thunder 9500 Series   |   RFL Competition Subwoofer Back to MTX Thunder 4500 Series The finest amplifiers deserve to be paired with superior quality subwoofers and component systems. Thunder4500 subwoofers feature the same ALDS (Asymmetrical Linear Drive System), common to all MTX Audio Thunder subwoofers (the flat progressive spider, combined with the extended pole piece). We've added some other touches to make sure these speakers perform way, way, past your expectations. The voice coil is wound on an Apical voice coil former for high power handling. The strontium ferrite magnet yields a highly efficient speaker (more efficient means better use of your amplifier power). The folded window basket is as durable as it is attractive.