At the subwoofer manufacturing facility in Michigan, we got a chance to see the Power subwoofers being built here in the US of A. Rockford has been producing subwoofers for over 20 years, designing and manufacturing their own subwoofers once they realized that nothing but the best could stand up to the power and abuse Punch amplifiers could dish out on a daily basis. We will be focusing on the process of building a Power series subwoofer from beginning to end.
The process begins in the engineering department. Here a group of dedicated individuals begin the process of developing new products, and testing out competitors existing products. Here they are developing some top secret stuff they didn�t want to tell us more about. Just for comparison, that is an 8� woofer at the bottom left of the last two pictures.
It all starts with a simple spool of copper wire. The wire is spun over a voicecoil former (the tube part). The voicecoil is then baked to cure the varnish that was applied. The process is pretty much the same between the Power and the Punch products outside of the fact that the Power series voicecoils are larger in diameter and longer in length (which is one of the reasons that Power series subs have higher power handling and longer excursions).
On the Power Series subwoofers, they take a different approach. Since the magnet is placed inside the subwoofer basket instead of on the back of it like the Punch series, they don�t have the luxury of building it from the bottom up. The first step involves screwing the speaker terminals to the basket. Here someone is getting the basket ready for attaching the magnet. The next step is involves sending the magnet down the assembly line where it is picked up by this machine and flipped upside down so the basket can be placed on top of it (keep in mind that the magnet on a Power series woofer can weigh close to 20 pounds so this speeds up the process considerably). Once the magnet assembly is bolted to the basket, the machine flips it back over and puts it on the assembly line to go down to the next station where the spider/voicecoil assembly will be attached. The serial is applied to the outside of the basket. From this point the subwoofer is scanned every time it enters a new station in an effort to document the woofers history in case any imperfection arises.
After the magnets are attached to the woofer, the next step is the attached the spider/voicecoil/cone assembly. In the case of the Power series subwoofers, the spider/voicecoil assembly is attached to the basket and then the cone is attached afterwards. In the case of the Punch series subwoofers, the spider/voicecoil/cone is attached as a single piece to the subwoofer basket. Here we see glue being applied to the basket of a Power series sub to attach the spider/voicecoil to the basket. The next step is to attach it to the subwoofer basket. Then they place it into a pneumatic press to make sure that the assembly is securely attached.
Next, they attach the cone to the spider/voicecoil assembly with an industrial grade adhesive (when you rate a woofer to handle up to 2000 watts RMS, you need to use the best materials to get the best results). When that is done, they take it to another pneumatic press to make sure that the surround is firmly attached to the basket. After that step they attach the dustcap to the cone with adhesive and place a large weight on top of the cone to make this glue joint is strong as well.
As an added measure to ensure quality, a sample of woofers are taken off the production line and put through a full battery of tests. One of the tests is a relatively low stress test called a Klippel analysis involving a calibrated laser and a super complicated software package. A Klippel analysis is the equivalent of a speaker dyno test, in this case they are making sure that all the published parameters are being met or exceeded (power handling, frequency response, etc.).
In addition to the Klippel test, they might also put a sample of subwoofers through a full power assault to make sure they are meeting their rated power handling. Not for a few minutes, or a few hours, but for 24 hours straight at full rated power. The room they use to conduct this test could be called the �Boom Room�. As you can see, those are 10 30001BD amplifiers, so that wall of amplifiers right there can put out over 30,000 watts at its rated power (and those amps are underrated so it is closer to 40,000 watts). The other rack of components is test and measuring equipment.
Only once they are certain these products will uphold Rockford Fosgate name will they be allowed to be boxed up and get sent to the warehouse for shipping to retailers all over the US. Here we see the product getting boxed up for shipment, in this case being packaged in a master pack of 6 8� woofers. As you can see they are very cognizant of preventing any kind of repetitive motion injuries for their staff. In particular, all the woofer boxes are moved by machine from the conveyor to a waiting pallet on the floor with this motorized arm.
