Hi tdesjarlais,
the idea of acoustically insulating/damping the insides of loudspeaker enclosures is certainly not new and has been used in High-end HiFi loudspeakers for decades, and it does contribute to a more defined sound.
tdesjarlais wrote: "I recently insulated my home speakers ... The difference was so significant that I wondered how well bose insulated their speaker cabinets."
I think that the emphasis here is on the subject of "home speakers". Are we talking serious loudspeakers here or maybe speakers from the lower end of the price range? If the latter is the case, then there's nearly always room for improvement as many compromises have been made to keep the price down (e.g. using low grade materials for the housing, cheap loudspeakers, little to no insulation/damping inside the enclosure, bad acoustic design ... the list is long). Almost any attempt at improving the insulation/damping of badly designed loudspeakers could well lead to an improvement in sound. Once you start taking a look at well designed high-end units I think you'd be pushed to make any improvement on the product. Such units have generally undergone years of development with several prototypes before they go into general production. I can't see simple trial and error DIY work offering any improvement in such cases.
I've just watched a youtube video titled "SECRET SPEAKER TRICKS AND TWEAKS, for better sound" and was appalled by the comments/statements from the person who had made the video. Should this be the one that you watched and want to try out on your Bose Compact loudspeakers, then I would say good luck and start saving up for a new system. What the man stated and showed in the video will most probably improve the sound of loudspeakers of the quality shown in the example. The quality of the build of the speakers is clearly not high. This can be seen just by looking at the outside of the enclosure that he's working on. There are other videos out there which may include the one which you may have seen. This was the first I came across just now by using "Google". Almost everything has it's place in life, but such practices as shown in this video I would say are not for use on High-end equipment.
As far as the construction and design of the loudspeaker enclosure of the Compact goes, I would really think that the Bose engineers who designed it went to a great deal of trouble in the R D (Research and Development) to ensure the best possible sound. Bose has been around for a good 50 years now and has made a real name for itself in the amplification of sound. They're not going to risk this reputation by putting inferior products on the market. Bose is also not to be described as "cheap", but neither is the sound which comes out of their audio systems.
Regarding the "hiss" you mentioned. Just about every PA system will hiss when no signal is being sent to be amplified. This is due to the Amplifiers in the system still being set at the volume needed for the gig but not being fed any signal. They are then amplifying what's always there and that's the noise coming from the different components in the system (components, preamps, cables etc.). As soon as a signal is sent through the system, this noise becomes negligible. If it disturbs you when the system is idling, you can turn down the master volume on the channel and turn it up when you start to use the system.
tdesjarlais wrote: "I do find an annoying hiss from the bose L1 compact tweeters when you turn the volume up above 50% that can be reduced by adjusting the parametric eq, using compressor or limiter or desser with the settings of the T1 mixer .... but it is not enough to still get the oomph that I need. You can certainly get the oomph from the speaker cabinet in the model size above this, but, my theory is that a tightly packed heavily insulated speaker will kick more than adequately and give enough sound boost that I won't need to go to the model above."
I own both a Compact and a ModelII. The Compact is great for what it was originally designed ... singer/songwriter with audiences of up to 100 people or just 50 people if they are a loud audience. For anything else I'd use the Model II.
Let me just try to give you one example of what I mean: If I needed to transport something not too big and not too heavy a pick-up would more than suffice. If, however I needed to transport something really heavy it wouldn't be enough to maybe strengthen the suspension on the pick-up, I'd need to start thinking about using a truck. I think that the Compact really delivers when you consider it's size but the time comes when it's capabilities are stretched to the limit and it can't cope any more.
"Please share your thoughts before I go into this project."
Well I've done just that tdesjarlais, but it may not be what you wanted to hear. If you really feel that you can improve on the performance of the Compact then you'll just have to try it. I would strongly advise against it, but it's your equipment. I would be very interested to hear about (and see) any attempts that you might make to improve on the sound of your Compact. Just don't forget that any warranty which the loudspeakers of the Compact may still have will be void as soon as you start "playing around" with the unit. Before you eventually damage the Compact you may want to have a look at a larger L1 for the times when the Compact is just too small. You'd then have the choice of 2 units which you could then use as required. Of course this comes at the cost of a new unit.
I hope that this has been of some help.
Tony