Ahh, yes, and so the typical goose chase begins. Now it's not new cables, or new amps, or room treatments that these speakers need, it's hundreds more hours of burn-in and granite blocks. Sure.
Burn-in makes a difference, but I've never had a speaker whose basic tonal characteristics changed significantly after burn-in. If a person isn't already satisfied with the sound, hundreds of hours more burn-in won't change this reality.
Once you give up on burn-in and get the granite blocks, people will be suggesting all manner of other fixes. Perhaps a new source? Better power conditioning? A better power cord? Enjoy. It's the speakers.
Well the bold statement I highlighted in your comment simply shows your lack of experience with speaker "break-in". Don't be upset that you've never heard a speaker transform completely due to "break-in". Not all speakers require it to such a degree. Some already have compliant suspensions while others don't. In the case of the Zu Tone's I believe that is part of the reason they may sound "thin" at first and the other reason is the sealed enclosure tuning.
The mechanical motor structure/suspension has a great deal of influence over the sound of a speaker. The suspesion provides a certain amount of physical resistance to the input signal. If the suspesion is relatively stiff it will resist movement (this is normal with many new drivers).
The idea is to loosen up the suspesion so it still does its primary job of returning the cone to it's resting position, keep the cone's motion linear etc but also doesn't get in the way of letting the input signal drive the cone evenly across the audio band.
Here is why this is important. The midrange audio frequencies only require the cone to move just a bit in either direction to achieve a certain level of output. However to reproduce low frequencies, that same cone will likely need to move 10-20x as much to pressurize the air in the room to the same level as it does with the midrange frequencies.
If the suspension resists moving a great deal because it is very stiff, the speaker may sound too prominant in the midrange or another way to say it - it sounds thin(bass shy). This is because it's not reproducing the low end frequencies at the same levels as the midrange.
By loosening up the suspension so the cone can react more easily to the bass input signal, you can indeed increase low end response - sometimes to a great degree so that the speaker seems to have undergone a complete transformation.
I've personally witnessed this in a wide variety of speakers and I know it to be true. Just because you have not witnessed or heard this happen in a speaker doesn't mean it can't exist. Plus you seem to want to heap this idea in with all the "tweaks" on the market. It's not a tweak. It is a simple matter of mechanics. Nothing more.
Basically you want to "stretch" the suspsension so it becomes "limber/loose" and more compliant to the signal input. SEALED DESIGNBeyond the loosening of the suspension the TONE is a sealed design so by its nature will generally resist movement more in the lower frequencies.
There are some drawbacks to using a sealed box, however. Using a box that's too small can have adverse effects both on your system's output level and on its deep-bass performance. Efficiency is another matter of concern; typically, sealed-box systems are less efficient than vented systems and require more power and equalization to achieve comparable output levels. Hence the reason why the Tone may sound thin in the bottom end.
If the Tone were a reflex/port loaded design, you would get a bump in frequency response right around their port tuning which will fill out the bottom end thus giving the listener a bit more fullness to the sound. My guess is that the tuning of this enclosure is up around 50-60Hz and rolls off gradually from there.
My suggestion of granite blocks was for the Druids (not the Tones which is what this thread is about)- I mixed this thread up with another thread which is discussing the Druids. For the Druids the granite blocks are not a "tweak" as you might have assumed. The Druids require very precise air gap height at the bottom of the speaker due to the Griewe loading technique employed. If a person was using the Druids in a carpeted room, the granite block simply lifts the air gap out of the carpet and allows more accurate control of the air gap height.
