Making it totally silent or making it totally noisy are both mistakes. Noisy in Aliens because they killed one of its young, and keep killing them. They're going to hiss and get mad when you kill them. Regardless of what you think, the Alien is based on insect principles, that's its genesis, and it was its development throughout Alien. Aliens was not the point where they decided to make them insect like, it's totally throughout Alien. When a nest of vicious army ants for example, gets intruded on by, say, a shrew. Shrew is toast. They crawl all over the shrew, and kill it, if they could scream you know they would. That's terrifying. I think that's something that should be expanded on. With all the over designed almost mechanical exoskeleton of the Alien, it should be making more noise, crunch wise. If you hear ants in a nest, the whole thing vibrates and you can hear them moving. In some ants, specifically the army ants I was mentioning, they make entire nests by grappling and grasping each other, and since they're so durable and strong, other ants can crawl through entire tunnels made up of ants.
For an Alien, the sickly crunch of the exoskeleton, the silent predation in a noisy environment to hide the noise of its movements (like the Nostromo), or the combined predation of a nest attacked should all take these insect qualities because they're absolutely terrifying, nature is brutal and the Alien is no exception. It almost sounds like a hokey concept, but imagine a nest of Aliens, pre-resin, where the creatures grapple onto each other, anyone who gets in this seemingly at first, resin like structure is grabbed and held while a facehugger somewhere in the cacophony, climbs in between one of their bodies and jumps onto this person, being held back by the hands and arms of the Aliens themselves, but there's just so many bodies you can't get a definitive idea where one Alien starts and another ends.
What makes the Alien terrifying, and this is such a cliche because everyone has a million ways of going about that topic, but one I've come to accept, is that it isn't the silent biomechanoid space assassin that makes the Alien. It is a giant bug, it has the mind of a bug, it is absolutely bizarre and mechanical looking, but it's shape is a parody of a human being. It has the ruthless on-off switch psychology of an arthropod but it's shaped like a man. It's almost in a way, a lot more Kafka than Giger. Try imagining, something shaped like a man, with an exoskeleton, capable of doing all the things insects and spiders do that make us so uncomfortable, and it has features that cannot be reconciled with, like a human skull covered in a translucent cowl, or a giant tubed head.
I'll give you an example of what I mean. Imagine if there's a roach in your room right now. This is hypothetical, I'm sure your room is clean and there are no roaches. But imagine it's just, moving around, cleaning itself, staring at you, in complete darkness, in some crevice in your room. What is it thinking, for a human being seeing something at such a scale of you would be awe inspiring and terrifying. For this roach, in this hidden crevice in your room, it just thinks "That could kill me" "I need to feed" "I must sleep" "Recover" "Ground" "Stick" "Avoiding", and moves on, without any interest, it just has these commands that register with it that are even more basic than what I just said. Now imagine that, but it's the size of a man. It breaks your arms and legs and traps you in gunk, these eggs open up, and you hear the crunch of this spider or crab like thing, and you're knocked out for a few hours. You wake up, and it's at your feet dead. You hear the crunching and slapping and slithering of so many Aliens moving about in this nightmarish hallway of half eaten corpses of the already gestated and there are bones everywhere. It's absolutely filthy. You feel the vibrations of the nest moving around, in this hard but delicate resin your strapped to, so they can feel when something that isn't them, enters a nest. And, you wait for an hour or two, and this thing comes bursting out of your chest and you die. And it is all done with minds, no simpler than that unsettling roach in your room. "Meat" "Soft" "I need to feed" "Soft" "Sleep" "Recover" "Ground" "Stick" "Call" "Stick" "Mother" "Child" "Home". Something like that, given the ability to scream, is bound to scream. And it's terrifying that it's this ruthless human insect, and it's screaming.