It is fine to get two geckos to live together in the same tank. However, more than this number would be problematic as the geckos would struggling the have a pleasant enough space to thrive.
Even with two geckos, certains rules should be followed to ensure their wellbeing:
1/ Only animals with similar size inside the same tank, as larger gecko could appropriate all the food of the smaller one.
2/ It is better to put females together, as males are known to frequently fight for territory and mates. Females do fight, but on a scale less severe than that of a pair of males.
3/ One or more females and one male only, this is fine but this WILL result in mating.
4/ Space is of the essence here as too tight an enclosure could mean that your geckos would struggling a lot.
5/ Quarantine for at least 60 days before putting geckos together to ensure that one of the geckos would not be sick and could spread to the other one.
So if you plan to raise more than one crested gecko, consider buying more reptile tanks for them.
Do crested geckos make noise?
Crested geckos do make noise. There are two typical cases in which the geckos would emit sounds.
First and foremost, during mating, the geckos would emit noise to attract partners. This is kind of a reproductive mechanism embedded in each and every gecko.
The second type of sound would be made if a gecko feels threatened. So if you pick up a crested gecko, chances are you may hear a chirping sound coming from it. This is meant to say: “Get away from me!”