Input Device Question

Hi guys, first time redditor

Working on improving the audio in the agricultural equipment dealership I manage.

Currently, I have a yamaha rx-v577 connected to a series of miscellaneous speakers at each corner of the shop (approximately 100'x100')

The wires running to the corners farthest from the receiver go all the way up to the roof and down, causing a fair bit of resistance, and a lower volume. I recently added a little amp for these speakers to compensate, what a difference!

My question:

I use the audio system to play the work bells for the beginning and end of work times, and also to play the Spotify group playlist the guys have put together.

Right now, I use an Amazon Fire 7 tablet to manage this alarm and music combo. The music will pause to play the work bell, and resume music once it has ended.

But the audio quality is less than excellent.

I thought it might be the aux connection on the receiver, so I am using an aux-rca adapter... Still less than ideal.

I am not looking for studio quality by any means, but perhaps someone has an idea for an input device to achieve a higher quality while still being able to play the work bell.

The receiver is capable of Spotify direct or whatever they call it, but I am unsure if I will be able to use the work bells? I do not have a remote for the receiver to test but would invest in one if this would be viable.

Thank you all, apologies for the wordy post.