Having seen the question a few time and dealing with it myself, i took on the modification of my helmet to allow for Sena Comm speakers.
My Shoei Qwest has pockets in it for speakers and its perfect.
My Shoei Hornet has no pockets and i could not put speakers in it without ripping my ears off when putting the lid on and taking it off.
So I did a modification. I was a little leery about cutting into the helmet with a Dremel but i got over and just went slow and took my time. Here are the results. Pretty painless and came in just about an hour of work. I doubt that I have really harmed the integrity of the lid, and I know that I likely voided any warranty. I clock lots of miles and the ability to listen to music, make calls and send texts is very important to me.
Fitted the speakers by putting in the velcro and seeing where they sounded best; then I marked the helmet and removed the speakers.
With the pointed bit seen in the photo I slowly and carefully cut out thru the plastic right on the marked line.
Removed the now freed plastic disk.
With a very fine rounded burnishing bit i slowly burnished down the foam until it was at the depth i wanted.
I used a cylinder bit to even up the sides and level the bottom of the pocket as well as push in the small bit of velcro that will hold the speaker in.
The speaker fits in perfectly flush and is held in with the little piece of velco as well as pressure fit as i cut the opening as exact as i could to the diameter of the speaker.
Put the liners back in and test the fit and sound of the speakers, which was spot on (if I do say so myself). The mod does not change the original feel of wearing or putting on or removing the helmet. I'm super stoked!
You can see the SMH and the speaker inside.