The best way to hear the cracks, is actually to stand about 2-3 feet away on the chaff collector side of the roaster. Once you are used to it you will have no trouble at all hearing 1st and 2nd again takes a little practice, but can be clearly heard.
The Gene Cafe is not quiet, but not really noisy and certainly much much quieter than the I-roar
If you are considering a Gene, then a read of the review should be of interest. I actually have a Gene (I used to have a 1kg Electric Toper and roasted on a 25kg Gas Probat). I Sold the Toper and kept the Gene for my own personal roasting. I also (again a personal view), think the Gene is a far superior roaster to the basic Hottop, much cheaper and no need to spend on filters every 20 or so roasts!
I played with one on friday...jury is still not out..guess for the home it is alright. I tried to do a lighter roast on an organic Colombian. I wanted a real light roast but it just wouldn't come together. I guess I am spoiled with more control on my commercial roaster. It is a bit better than the hottops hands down.
The gene needs a bit of practice Topher and the information about how to roast in the manufacturers guide is complete rubbish (the temps are far to high for a start). One of the main tricks is to reduce the heat input after 50-60 seconds or so of first crack, this also prevents scorching as it reduces the thermal gradient within the roasting chamber and a 250g batch size seems to give the best results.
The roasting is rather counter intuitive in some respects to the larger drum roasters, so it's just leaning to modify your technique. Once you get the knack, the roasts are reasonable and not far off what can be achieved in the drum roasters....they certainly lack the brightness of a fluid bed roaster like the I-roast.
I can answer my own question now that I have done a few roasts on a Gene Cafe. The Gene Cafe is much quieter than the I-Roast. Conversation is easy and the sound is only that of pebbles in a slowly turning jar.
It is a funny thing, though, hearing the cracks. I don't think they are any easier to hear than with the I Roast. The first couple of roasts I didn't hear them at all but now I am getting more attuned to this machine and I am starting to hear the pops. This is similar to the I Roast.
But training to hear is much nicer without the shop-vac roar to listen through.
Bill I hope you read the stuff on the Wiki about roasting in the Gene, as there is quite a different technique you can use, which makes sense considering the Physics of the roaster. If you want to see a LOT of detailed online roasting logs (and other coffee roasting information) for the gene and a few other roasters, look at the link below.