I have the hammer v1 and love it. With JB reflect ear buds (these seal really well), noise is not a problem for the person on the bike. I think the non bikers are either OK with that, or exceedingly polite.
Only thing I’ve found the works is keeping the Hammer rpm low by using a low gear, either in erg mode or by turning up the resistance percentage. I’m almost always in the small ring and middle to larger cogs. It really starts to sing at high rpm.
Also, the belt will start to make crackly noises when coasting sounding for all the world like bad bearings. Flipping direction of the belt or putting in a new one will cure it for a while. It’s not a functional issues and compared to the rest of the noise it’s nothing to be concerned about.
The toothed belt is the culprit. The H3 uses an entirely different type of belt and pulleys.
As it happens, I did try testing my last ride using the small ring with a straight chain line. Can confirm the reduction in noise.
Also easier to flit from high cadence sweet spot intervals when dropping to the rest phases. Seems to be less of a spin down which I assume is due to the flywheel spinning at a slower rate even though my cadence remains high.
Another thing I have noticed is that the mileage that it reports is lower when using this lower gear. Again, I assume that the slower flywheel is the reason behind this?
As for workout being achieved, can I assume that this would be the same when using ERG mode, no matter what gear is in use?
Basically the trainer adjusts the resistance and I end up doing the scheduled power and the aimed cadence and this is the same regardless of chosen gear?
Gearing (hi vs lo) can feel different to people depending on their trainer, training history, weight, outside riding experience, and a host of factors.
One basic approach (that does not cover the real depth of the topic) is to try to mimic the flywheel inertia with respect to the majority of your events outside.
Flat and Fast Road Riding = Use Higher Bearing and Faster Flywheel Speed
Hilly and Off-Road = Use Lower Gearing and Slower Flywheel Speed