When working with tidying up the sonic from Cabinet Speakers and not working with the Electronics (Xover Component Exchanges, Internal Wiring) or the Cabinet Internal (Port Dimension, Internal Volume, Reflection Treatment, Bracing) , the options left are to work with external influences on the Cabinet.
Cabinet Resonance Control, along with methods employed to improve the coupling of the speakers drivers to the ambient environment, by carrying out tasks such as a Room Treatment, are the most easy to create a experience of and evaluate the methods employed.
Not every body can go down the Room Treatment route with gusto. There are usually others with a keen interest in the space to be treated. Aesthetically the materials / methods used can prove to be contentious to others being expected to embrace the presence of such additions of materials and structures to the room. Pleasing aesthetic materials/structures used for treatments will come with a cost, and might be able to be more attractive to be lived with, where others are to be present.
Cabinet Resonance Control is the most unintrusive place to start, especially when it comes to the aesthetic impact.
Cabinet Resonance Control is also a bespoke treatment and will be unique as a experience for each individual when assessing control measures being employed.
Different perceptions of the produced sonic will be found in the different spaces Speakers are Set Up in. The influence of the controls measures being employed will vary with impact in different environments. The end result being, not all experiencing the sonic produced will be in agreement that it is suiting their own personal preferences.
Hence, the inquisitiveness to create a change manifests, usually this leads to investigations to learn suitable methods to create change. As an individual becomes more knowledgeable and have a improved grasp of the subject of methods that can be employed, subjects such as the OP in this thread will be seen.
For those just entering into this subject, there is a little info that might assist with giving a better grounding (pardon the pun).
As soon as the Speaker leaves the Manufacturer, it is typically going to become a speaker that is no longer the speaker that has been designed to deliver a particular sonic. Once the speaker ends up in a new environment such a space at a Event, space at a Dealers Demo' Room or in a space within a Home. Each of these Spaces is very very different to the Space used by the designer/manufacturer during their pre-production R&D.
The same model of Speaker in all these different environments, even though aesthetically the same, will be producing a sonic that is quite unique.
'Are you feeling lucky', what is the chances that the environment one is using to set up the speaker, is as close to optimised for coupling to the speakers drivers and create a sonic difficult to be improved?
This leaves the option to try a few things out to see if a Tidy Up of the sonic being produced can be achieved. The very good news is that most who have made attempts have at some point discovered a sonic that is an improvement in their assessment.
In general the Floor Standing Cabinet can be interfaced with the room, by having a direct coupling of the cabinets base to the flooring material. Stand Mounted Speakers are able to benefit in very similar ways, but the stand mount could prove to be a compromising element in the assembly.
From this point on the methods that can be employed are not too many, but the costs associated with creating a method can vary substantially.
Spikes directly coupled to the floor or separated by being in contact with other pad material solely used to separate the spike from the floor, this can easily become a Plinth/Sub Sub Plinth using Spikes as separators.
Pads, either used to receive a Spike, or be used as the material separating the cabinet base from the floor, ( Foam, Cork, Woods, Metal, Plinth/ Sub Sub Plinth using Pad materials as separators and configurations of these in differing assemblies).
Suspension (Purpose Designed Podiums/Sleds, Springs, Pneumatic, Plinth/Sub Sub Plinth using separators that are suspension and other configurations of these)
In a room made up typically of Six Surfaces, of which room dimensions are going to vary widely and construction materials for Floor, Ceiling and Walls are going to be quite varied in their properties and influence on the speakers produced sonic. It becomes very difficult to predict which method that can be employed as an attempt to Tidy up a Sonic produced from a speaker will work to meet the individuals unique preferences in their listening environment.
As a strong suggestion, start with very affordable items to create changes to the mounting of the Speaker, these methods might just be enough for your environment, there may not be any need to extend to costlier items to function as the same role. I have this as a discipline ingrained today, even though I could immediately commence with the use of costly items to support my investigations.
When one feels that they have found a place where the Tidy Up of the Sonic has met their unique preference, there is the option to add weight to the top of the Speaker cabinet. By doing this it might show a cabinet resonance has been present . The added weight can create a reduction in audible resonance, which for some might be the desired level of Tidy Up they have been looking for.
No Room Treatments so far, but a sonic may have the capability to impact on objects present. Any ornament or similar thing that Vibrates or Rings in the room, can be bedded on a little Blue Tak, if it has to stay in the place of display.