This is an isolation issue, muffled and uncontrolled are not terms I would use in regard to this model of VPI. Hardness is not a term I would use with VPI either. They can sound congested when not using proper isolation.
I've experimented with many platforms, properly draining internal and external vibrations is manadatory. The uncontrolled and muffled bass you're hearing is a symptom of vibrations being reintroduced into tt.
Wall mount necessary with springy floors. Sandbox, Symposium, Nuance, etc. platforms with either stand or wall mounting. I never use anything springy directly underneath mass loaded tt designs. Still waiting for a good explanation of using any suspension under VPI's.
I've experimented with many platforms, properly draining internal and external vibrations is manadatory. The uncontrolled and muffled bass you're hearing is a symptom of vibrations being reintroduced into tt.
Wall mount necessary with springy floors. Sandbox, Symposium, Nuance, etc. platforms with either stand or wall mounting. I never use anything springy directly underneath mass loaded tt designs. Still waiting for a good explanation of using any suspension under VPI's.