Sigma Onyx Pro Heart rate monitor low beep volume

[Martin]

I have a new Sigma Onyx Pro Heart rate monitor which has some very nice
capabilities for the price and appears to work well. I am interested in
other users' opinions on the beep volume & display contrast

The monitor I have has a very poor beep volume compared with my old
Polar A3. When riding in a group I had to turn the sound of my Polar HRM
off to avoid annoying other riders, but I can't hear the beeps from my
new Sigma at all, even with the volume set to max.

The Sigma also has a lower display contrast than the Polar which may be
due to the background being a little darker that background on the
Polar. The contrast is important to me because I am only just able to
read the display in good light without my reading glasses. I know I am
fighting a losing battle here and will eventually have to use some form
of reading lenses when I ride, but I would like to postpone that as long
as possible.

I bought the Sigma from BikeWorldUSA via Amazon. Are low beep volume and
low display contrast common to these HRMs or is mine faulty?

Thanks in advance for your comments and experiences.

--
Removed z before replying by email.