Final Assembly  

The final assembly lines at Eminence represent 35 years of ongoing research and development in loudspeaker manufacturing technology.  Eminence is always developing new tools, machines and innovations for loudspeaker manufacturing keeping the employee's and customer's best interests in mind.  Comfort, quality, efficiency, and increased productivity are always paramount in these developments.

Many loudspeaker manufacturers have chosen to eliminate the human factor in their manufacturing processes.  At Eminence, we believe that our employees are one of the critical factors to our success, by constantly contributing to the consistency and quality of our products.  Each employee at each station monitors the quality of the product as it progresses through the production process.  No robot is capable of providing such control.

There are two final assembly lines for loudspeakers here at Eminence.  Although both lines have similar capabilities, Line 1 typically produces 6.5" to 15” speakers with lighter weight metal/magnet assemblies.  Line 2 typically produces speakers from 8" to 18” with heavier weight assemblies.  This configuration allows for greater flexibility in changing from one product to the next and in production scheduling.

Each assembly line has 19 employees that contribute to the actual assembly of the loudspeaker.  There are several additional employees that provide support in the form of setup, warehousing of raw materials, and supervision.

All Eminence manufactured speakers are carefully monitored from the beginning of the manufacturing process until they leave our facility.  Each speaker is given a unique code so that we may determine the history of each component and who was responsible for each stage of production.  For example, we can determine who installed the dust cap on a model last year.  We can tell you the day it was built, who we built it for, the assembly team that assembled it, and where we shipped it. 

The final assembly process begins with the assembly of the core and back plate along with the magnet to the basket and top plate.  This stage of speaker production is particularly critical, as the core must be centered exactly within the opening in the top plate and the magnet centered on both plates.  Eminence has developed a special process to ensure that alignment of these components is consistent and accurate.  Special adhesives that adhere quickly are used to make the bond between these parts so that the assembly can continue in the production process without delay.

The next step is the attachment of terminals to the metal assembly.  This process incorporates the use of rivets, screws or adhesives depending on the terminal chosen by the customer.   

The assembly then receives an application of adhesive that will bond the cone to the basket.  By the time the assembly reaches the cone setter, this adhesive will have perfect properties for ensuring a permanent bond of the cone to the basket.

One problem that almost every speaker manufacturer has encountered is the introduction of foreign particles into the voice coil gap.  Just prior to inserting the voice coil, Eminence uses a special process to remove any of these particles and guarantee a debris free motor structure. 

The voice coil is then precisely positioned in the motor structure.  The (vertical/axial) position of the voice coil relative to the top plate determines a great deal about  the performance of the speaker.  Different positions lend different performance.  Again, Eminence has developed a proprietary manufacturing technique that results in coils being set to within a few thousandths of an inch of their original blueprint.  Equally important is that the coil be centered (horizontally/radially) in the gap to prevent voice coil rubbing and ultimately failure.  The Eminence coil setting process ensures this positioning as well.  Once again consistency is the issue.  We must be able to guarantee our customers that each product will be the same time after time.

Once the coil is positioned, the spider (lower suspension) will be installed and bonded to the coil and basket.  The cone is then set and bonded to the basket and lower suspension.  This operation is performed manually by experienced cone setters to make certain alignment is correct and to double- check the quality of the cone.  These individuals have collectively set more cones than any other group of people in 
the world.

The loudspeaker then moves through a brief process to stimulate activation of the spider/cone/coil joint adhesives.  Next, the voice coil leads are threaded through the cone and the terminals.  The operator will check the path of the leads to ensure they are placed in an exact location to reduce future stress and eliminate potential failures.

Once the leads are in place the speaker will receive any cone or edge treatments necessary to lend the desired performance.  This process is also done manually.  Eminence uses a variety of treatments depending on the application of the speaker.  The treatment may be limited to the surround or may include the surround and the cone. 

The next procedure involves applying a special dressing to the lead wires from the coil to where they exit the cone in route to the terminals.  This dressing will protect the leads by encapsulating them and preventing their movement.  This procedure is also done manually to control the amount and placement of the dressing.

We are now ready to install the dust cap and gaskets.  Eminence has developed special machinery to apply these  adhesives in exact quantities and locations.  Placement of these components is still done manually to maintain visual control of their placement.  Remember, each operator is checking the quality of the work performed before the speaker reaches their station.  If at any point there is a quality issue, the problem will be corrected or the speaker will be completely rebuilt.  

To this point in the process the lead wires have been threaded through the terminals but not secured to the terminals.  The length of these wires is critical.  If they are too long, they  will flop around and  potentially damage the cone or spider and could even fail.  If they are too short, they could restrict the cone travel and cause failure.  Each speaker model is different and requires that the length of the leads be determined accordingly.  Our operators are experts in this process.  Many manufacturers choose to use solder to attach lead wires to terminals.  Soldering can be harmful to the environment and to our employees.  Eminence has chosen to use a crimping process in conjunction with an adhesive to make this permanent connection.   

The basic construction of the product is now complete.   The speaker will now be magnetized and inspected.    Once, the final assembly team is satisfied that the product meets our quality standards; the speaker will be sent through an oven to reduce the drying time for the various adhesives and will continue on to the Pack/test department for further testing and preparation for shipment.