I normally don't listen to anything but don't see much difference between having ear buds in or having a stereo blasting loud enough to hear when wearing a helmet with respect to traffic noise etc.... My comment had more to do with the quality of sound and expense related to what you end up with buds vs speakers, amp(s) sub etc. I am sure that there are good cycle sound systems out there, I just have never heard a decent one.
As I get older I find I enjoy the wind and quiet more and having tunes on all the time less but thats just a personal choice.
I'm not disagreeing with you, only sharing my experience, thoughts and such.
With the bike speakers facing backwards, we are actually driving through the music sound waves. The music can travel into the helmets, and through the face shield, quite easily so it doesn't have to be played at real loud volume to hear it well enough.
I completely understand where you are coming from too, where enjoying the natural sounds while riding, can be just as enjoyable if not more so, than of our favorite bands belting out the greatest hits. You actually get to think too!!
The reason they make motorbike stereos with speakers opposed to just matching wireless Bluetooth headphones or high quality ear buds in helmets is certain. And if it was a good idea, there would be helmets with awesome sounding speakers built in.
In fact, even though traveling at much slower speeds while riding on a regular bicycle, I still don't think it's very wise, to block out the important sense of hearing the traffic and any activity around you. Unless you are riding off road and riding through Stanley Park, or similar places near you. The problem I see with 99% of all accidents, is that they're usually caused by the other guy, not us. So We must be aware of Our surroundings at all times and all elements that could potentially be dangerous to us. If Only to get out of the way.
By the way, those ear buds that you mentioned above, are extremely good, and will serve you very well... Enjoy 'em!!
But not to drown out "traffic noise" as you call it... ;-)
For $1,500 installed, that speaker system seems like a steal of a deal too, with its marine speakers and all. Yes, it is a lot of money, for what you're buying, but nothing in comparison, to staying alive, to ride another season...
If you can ride, while wearing your earbuds, and hear your friends voice talking in a normal voice, then you should be ok. But keep the volume low. And be checking both of those rear view mirrors constantly.
Ride safe, and long.
Happy trails friend.
Chas