Over the years I've discovered the benefits of chassis vibration dampening when mounting midbass / midrange drivers on most types of baffle surfaces.
The largest benefit I've observed was by fully isolating the driver chassis from the baffle structure using viscoelastic materials as well as other elastomers and polymers. The latest project I'm planning to do this with is on my large 3 ways using the Eminence Canna-bass CB3012-N8 woofer /midbass, Bliesma M74A and T34B.
Some of the lighter weight cast frame drivers can be prone to resonances due to chassis flex. This somehow needs to be supressed when using the driver for more critical hifi applications. You can observe the main effects of these resonances by observing the impedance sweep of the chassis in free air vs clamped in a baffle. The resonances are usually found in the midbass region between 200 - 800 hz in form of smaller impedance peaks. The trick is isolating them from spider resonance and radial cone modes occurring in a similar region.
I purchased some supplies online and from a local hardware store. I chose #10-32 screws with a shallow allen head for the Eminence 10s which fit perfectly in the recessed chassis bolt hole pockets. I'm using 1/4" OD, 3/16" ID flanged grommets (typically used to isolate hoses passing through metal from rubbing). These fit perfectly around the 10-32 screws and locate the driver on the baffle flange. A small washer under the screw head will be needed to keep the underside from, twisting the grommet while tightening the driver down. Of course I'll be using either a strip of neoprene or sorbothane between the chassis and baffle flange. This will fully isoate the chassis from the baffle surface.
The largest benefit I've observed was by fully isolating the driver chassis from the baffle structure using viscoelastic materials as well as other elastomers and polymers. The latest project I'm planning to do this with is on my large 3 ways using the Eminence Canna-bass CB3012-N8 woofer /midbass, Bliesma M74A and T34B.
Some of the lighter weight cast frame drivers can be prone to resonances due to chassis flex. This somehow needs to be supressed when using the driver for more critical hifi applications. You can observe the main effects of these resonances by observing the impedance sweep of the chassis in free air vs clamped in a baffle. The resonances are usually found in the midbass region between 200 - 800 hz in form of smaller impedance peaks. The trick is isolating them from spider resonance and radial cone modes occurring in a similar region.
I purchased some supplies online and from a local hardware store. I chose #10-32 screws with a shallow allen head for the Eminence 10s which fit perfectly in the recessed chassis bolt hole pockets. I'm using 1/4" OD, 3/16" ID flanged grommets (typically used to isolate hoses passing through metal from rubbing). These fit perfectly around the 10-32 screws and locate the driver on the baffle flange. A small washer under the screw head will be needed to keep the underside from, twisting the grommet while tightening the driver down. Of course I'll be using either a strip of neoprene or sorbothane between the chassis and baffle flange. This will fully isoate the chassis from the baffle surface.
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