Ultra LS 2.25
Critical Mass Systems’ adjustable loudspeaker footer: a purpose-engineered resonance-management system that replaces conventional spikes while maintaining precise contact through changes in speaker height and rake angle.
Key Features
- Developed specifically for floor-standing loudspeakers
- Derived from Critical Mass Systems’ Center Stage footer technology
- Rounded lower structure maintains alignment with the floor
- Height-adjustable internal spike mechanism
- Approximately 0.25 inches of vertical adjustment
- Supports level or rearward-raked loudspeaker positioning
- 3:1 turning ratio reduces the torque required for adjustment
- Clockwise adjustment raises the loudspeaker
- Counter-clockwise adjustment lowers the loudspeaker
- Built-in safeguard prevents overextension and detachment under load
- Mechanically separated outer shell redirects floor-borne vibration
- Designed to manage excess energy within the loudspeaker cabinet
- Recommended settling period of at least 7–10 days
Design & Build
The ULTRA LS 2.25 was developed to address the substantial vibrational energy generated by loudspeaker cabinets and driver arrays. Its rounded lower structure maintains precise alignment between the loudspeaker and floor as the footer is adjusted, whether the speaker is positioned level or with a rearward rake.
The lower ball structure functions as a height-adjustable spike. Under load, the black outer shell separates mechanically from the footer’s internal structure, preventing vibration from travelling upward through the exterior shell. Floor-borne energy is instead directed through predetermined internal paths, while the upper structure manages resonance transmitted from the loudspeaker.
System Pairing
The ULTRA LS 2.25 is designed for conventional floorstanding loudspeakers in properly configured two-channel listening rooms. Its adjustable height allows precise levelling and rake-angle optimization during speaker setup.
Existing aftermarket speaker supports should be removed before installation. Critical Mass Systems recommends allowing 7–10 days for the loudspeaker-footer system to settle and approximately 14 days before making a final performance assessment.
Technical Specifications
| Specification | Detail |
|---|---|
| Type | Height-adjustable loudspeaker resonance-control footer |
| Loudspeaker contact diameter | 1.5 inches / 38 mm |
| Top diameter | 2.25 inches / 57 mm |
| Maximum footer diameter | 2.5 inches / 64 mm |
| Height, fully contracted | 2.25 inches / 57 mm |
| Height, fully extended | 2.5 inches / 64 mm |
| Adjustment range | Approximately 0.25 inches / 6.4 mm |
| Weight | Approximately 11 oz / 300 g each |
| Height adjustment | Rotate clockwise to raise; counter-clockwise to lower |
| Turning ratio | 3:1 |
| Lower structure | Rounded, height-adjustable spike assembly |
| Overextension protection | Internal safeguard prevents detachment under load |
| Outer-shell operation | Mechanically separates from the internal structure under load |
| Orientation capability | Supports level or rearward-raked loudspeaker positioning |
| Recommended application | Floorstanding loudspeakers in two-channel audio systems |
| Settling period | Generally 7–10 days; at least 14 days recommended before final evaluation |
