Surrounds are made with many different degrees of compliance (stiffness). To obtain the correct amount of cone movement and thus the same volume of bass and low distortion as our original design, we use only our original type of surround.
When refoaming the voice coil must be realigned, and correct alignment is also critical. One method is to cut out the dome cap in the center of the cone and use shims. This destroys the dome cap and generic replacements alter the frequency response and change the sound of the speaker. The other method of alignment is to move the coil-cone assembly around until you don't hear the coil scrape metal. Some use a test tone, but this only makes the scraping louder. Neither of the methods gives any indication of when the voice coil is in the center of the magnetic field. We use our exclusive electronic alignment process that centers the coil with perfect symmetry, allowing linear cone movement and minimum distortion. This along with an undisturbed dome cap and the proper surround insures that the speaker will perform and sound the same as when it was new.
We check all the following:
Impedance Buzz and rattle Integrity of dome attachment to cone Integrity of coil attachment to cone Integrity of coil attachment to spider Spider adhesion to frame Integrity of magnet, plate, and frame attachments Accelerometer output and distortion Input lead integrity and dress We clean the input terminals if needed.
We also use polyether foam which lasts much longer than
other types of foam, along with Airflex adhesive. It remains
flexible, the same as that used for original construction.
Three working days, and all repair is overseen by Bill Watkins. Guarantee is five years.
For our business background, click on credentials at top left.