How long does the noise go on?

I've had a look on google maps and it seems you may be very close to the only disco in Calpe, the Disco Camaleón and judging by the reviews it only really gets going from 2 am until 7 am and is open year round although I imagine it will be quieter outside of high season.
As estate agents are paid handsomely by the seller they are not likely to point out anything which could affect a sale, it is not their job although during the viewings, as salespeople, they will come across as your new best friend. As a good percentage of people when buying holiday homes are not familiar with the area in which they are buying, things like this often happen and there is a lot of advice on here about visiting at different times of the day and year and doing a lot of your own research before buying. If you used the solicitor recommended by the estate agent there is even less chance that they would mention anything untoward.
You have my sympathy.

Don't really know Calpe but I'm pretty sure it won't be untypical of the dozens of other beach holiday locations in the region and as such it's likely it's going to be noisy - if not very noisy - both in the Summer and at other holiday times, and probably well into the night, clubs and discos etc. don't usually kick off much before 10 and then carry on until daybreak. Not sure what else you expected?

Even without that and at the best of times the Spanish alone are inherently noisy and don't seem to be capable of conversing without shouting and play their TV's at full volume with all the windows open so if you want peace and quiet then you have to get well away from the coast and preferably stay away from towns too. Even then there are seemingly incessant fiestas and other spurious celebrations each with their attendant blaring music and fireworks the noise from which carries for many miles and through the night. 

'Realtors' work for sellers not buyers so unless specifically asked are not going to volunteer the downsides of a property or location, and would likely downplay if not actually lie about them anyway, but frankly if you went actually seeking a property in such a location then it would not have been unreasonable for a 'realtor' to assume that you knew what you were doing. 

Sorry but it's Caveat Emptor I'm afraid and if you've made a mistake which you can't live with then there is only one way out! 

My family has been in and around Calpe for the last 50 years, and, alas, it is no longer the small quiet fishing village it once was. Even living well outside the town centre, the noise and reverberations from nightclubs, discos etc can be unbearable especially during the summer months. You either have to get used to it, or, as others have said,,do the other thing!

I completely sympathise with your predicament, but buying anywhere in a town with a high holiday population on the coast is not really going to give you a quiet life.

Funnily enough we did visit ourselves in the evening, but were not around at 10 pm - 7am.  I only recently discovered the noise issue because I was reading reviews on bookings.com of people who had rented apartments, I was just being nosy. Then I delved a little further and discovered people complaining vehemently about the noise. When we asked the committee from our apartment building ( that we have not even moved into yet) , they said they have tried for years, and have achieved at least getting the road closed to cars and a bigger police Presence. It is also  disappointing to read about the deception of estate agents and the lawyers. We actually found this apartment ourselves while working with an agent from Calpe..... but she was willing to sell us one that was very close by. When we asked the lawyer just recently about the noise she said oh yes that is a big disco and bar area. 

Agents will not care about the noise, all they can see is their big fat commission and the € signs in their eyes.

Unless asked directly, it is not really the agent’s remit to pass on this kind of information; they are working for the client and their job is to achieve a sale; having said which there are unfortunately agents around who will prevaricate and avoid the question.

I can understand the view of ‘big, fat, commission’, but in all seriousness, do you expect agents to work for nothing? Like all businesses they have offices to run, overheads, staff to pay, cars to run and so on. One contracts an agent knowing their costs - which are not paid by the buyer - and they are expected to work for it. This is not an apologia for bad agents, but there does appear to be a general attitude that service industries should magically provide said services for nothing!

Making a living is one thing but just have a look through the many posts on the Forum that give the true picture of the many unscrupulous agents around the Costa and their underhand methods and deals with other agents and their preferred "lawyers" where thousands of Euros disappear, neither going to the buyer or the seller.

I agree that it’s very disappointing, and one does keep hearing about this. Whilst estate agents are largely unregulated, abogados are registered with the Spanish authorities and complaints can be made against them.

Presumably your lawyer did all the due diligence on your purchase - but again, the noise issue is not really something that she could be expected to warn you about as such, as her remit is really the legality etc of the proposed purchase.

I understand, and this unfortunate behaviour does seem to have been prevalent. However, even in UK, it is the first rule of thumb NEVER to use any lawyer/abogado recommended by the agent. And I believe many of the dishonest transactions here have involved non-Spanish ‘solicitors/lawyers’, neither of whom are qualified to practice in Spain as it is not a recognised term - albeit I understand that it is unused as an easy translation for the understanding of the British.