For the ninth time in as many hours, the couple upstairs went at it yet again at 4 a.m. Tuesday, hammering away at one another in an impressive display of sexual stamina and tenacity, apartment-directly-below sources said. 'There they go again,' said downstairs neighbor Murray Schuman, a 41-year-old bakery owner who gets up each day before dawn to decorate cakes, as a steady, rhythmic thumping knocked plaster dust from his ceiling for the umpteenth time. Eleanor DiPaoli, a resident of the Brooklyn, NY, brownstone where Peter Kafka and Rachel Brown have been going at it like rabbits for hours on end. The couple, 26-year-old advertising copywriter Peter Kafka and his live-in companion, graphic-design specialist Rachel Brown, have reportedly been banging away ever since moving into the three-story brownstone last May. Both are said to be relatively quiet and conservative in outward appearance, qualities that belie their insatiable animal appetites and tremendous capacity for vigorous sexual exertion. Said a bleary-eyed Schuman: 'They seem like a nice enough couple, and they always say hello when I run into them in the building's front lobby. But right now, I just need to get some rest. It seems like every night, just as I finally start to drift off to sleep, the gasping and pounding kicks in again. They start out gently, emitting little gasps of pleasure, and then gradually increase the intensity and tempo, eventually building up to full-strength shouts of 'Give me what I need!' and what have you.' 'Those two are a couple of real troopers, I'll give them that much,' Schuman said. 'They take care of business. Once they get started, they don't let up.' Schuman said he normally wouldn't complain, but he had been tossing and turning for hours, and this business had been going on all night. As a high-pitched, seemingly endless chant of 'Let me have it!' cascaded down from Kafka and Brown's third-floor apartment, he began banging on the ceiling with a broom, shouting that it was the middle of the goddamn night. Schuman is not the only building resident who has been affected by the constantly going-at-it couple. 'Always with the schtupping at all hours,' said apartment 2-B occupant Rose Teitelbaum, a retiree who has lived in this building since before you were born. 'In my day, such a thing, it was shameful, a scandal. It is like a bordello, I am telling you. Such a racket! And unmarried, nu?' Teitelbaum, whose bed is directly below Kafka and Brown's bathroom, site of their 9 p.m. and 11 p.m. sexual encounters, said the whole neighborhood is talking, and that she fears some days even to show her face for the embarrassment of having such flagrant and indiscreet young persons living in this, her building, where her own mother taught her so many years ago to show respect. According to neighborhood sources, the building has not witnessed such frequent, vigorous and vociferous sexual intercourse since May 1991, when the second floor walk-up was briefly occupied by a bicycle messenger named Ramon, who regularly kept residents awake with repeated late-night dalliances with someone he reportedly referred to as 'Madre de Dios.' Ramon left after just two months to pursue a modeling career in Los Angeles, sources said. Since then, however, many building residents have been fearful that the increasing gentrification of their neighborhood and subsequent influx of ambitious, young, sexually active college graduates may permanently alter the working-class, retiree neighborhood's placid atmosphere. 'For thisthe gasping, the thrusting, the pounding, the shouting in the middle of nightI pay taxes for 53 years?' Teitelbaum said. 'Thank heaven my hearing is not so good as what it used to be, or I wouldn't get one wink of sleep with all the oohing and the aahing and the screaming like the gorillas in the jungle.' Despite such strong opposition to the couple, widow and longtime building fixture Eleanor DiPaoli has been staunch in her support of Brown and Kafka. Claiming that young love is the most beautiful thing in all the world and that detractors like Teitelbaum are dried-up old bats who should only be so lucky, DiPaoli defended the couple's right to go at it whenever and as loudly as they wish. 'In my day, the Earth itself would move from the titanic force of my late husband Salvatore and I making with the romance in the midnight hours,' DiPaoli told reporters. 'I would sing out in joy like an opera singer, with long sustained fortissimo arias. I was known as far away as Flatbush Avenue for the crescendos of passion I set forth on those breathless nights. Then my Sal, God rest his soul, would suddenly switch the tempo doppio movimento, and my heart would swell with joy. And those afternoon intermezzos, when he'd sneak back from the warehouse and call out 'Mi amor!' with his hands full of flowers and his smile full of love, oh, that I will never forget...' DiPaoli went on to speak at great length and in lurid detail before eventually falling asleep in her chair. 