Noisy lasers

[Darkhstarr]

IMTU lasers are not silent but quite noisy, similar to the crack of thunder. Makes a certain sense any laser beam powerful enough to burn through a target travelling any distance is going push aside air molecules much in the same way as lightning does. I wonder if any other GM's & players have noisy laser or go with silent lasers?

 

[Easterner9504]

IMTU Lasers give a quiet hum to let shooter know it fired.

Lightning is electricity that heats the air causing thunder, it gives off light. Laser is just light so mine pass through air quietly.

 

[samuelvss]

Lasers are quiet, until their termination, where they make crackling explosions. Being shot with a laser is not a silent process, but there is no other sound. Fusion and Plasma guns will deafen you without hearing protection, on the other hand. Gauss rifle needles crack as they pass, but have no other sonic signature.

 

[Icosahedron]

AIUI, the sound from lightning is due to the explosive expansion of air due to local heating by the electrical discharge. If air is relatively transparent to the laser (a desirable feature for range purposes) there should be minimal heating of the air, and as Easterner says, light doesn't push air aside, so the laser should be effectively silent.

Ship ordnance size weapons may create ionization of the air and may be visible and audible as a result, and any laser may make a sound when it explosively vapourises the target material.

I'm sure there was a thread about this perhaps a year ago?

 

[DeusX]

Lasers are quiet, until their termination, where they make crackling explosions. Being shot with a laser is not a silent process, but there is no other sound. Fusion and Plasma guns will deafen you without hearing protection, on the other hand. Gauss rifle needles crack as they pass, but have no other sonic signature.

I'd read somewhere that a laser beam in dusty air would create a line of sparks as the dust vaporized. Would that make any noise? Crackles or hiss?

DX

 

[Blue Ghost]

I'd read somewhere that a laser beam in dusty air would create a line of sparks as the dust vaporized. Would that make any noise? Crackles or hiss?

DX

That's my understanding as well. They make a sharp snap at high enough power.

 

[kafka47]

As I play a very cinematic game and include sound effects during play. My lasers do make the standard sounds. As players depart from a scene or emerge from something...it is better to cue the sound effect then roll for damage. I suppose, if I were to play it hard...there would be no sound but things like chargers.

Then to have the standard narration...(sound of dice rolling).
Ref: "Your ship shakes with a percievable shutter." (sound of dice rolling) and your dorsal wing has just been clipped by a pulse beam.

Although, I do make exceptions to my rule for things like X-Ray lasers and other stealth/sniper weapons.

 

[Gadrin]

If you have it (not to mention if you like their explanations) they take the time to explains most of the beam weapons in their RPG in the GURPS Vehicles 2e book on pages 123-124.

>

 

[DeusX]

If you have it (not to mention if you like their explanations) they take the time to explains most of the beam weapons in their RPG in the GURPS Vehicles 2e book on pages 123-124.

>

Thanks for the reference. For those of us without ready access to it, could you comment on what they say on noise-levels in the spirit of fair use. Noise or no noise? Where do they stand in the debate?

We must have a physicist in the room? I've done a little lidar engineering work in a previous life but only low-power.

Also on the topic of lidar, should I start a topic on personal point defense lasers(PPDL) i.e. why Imp marines laugh at RPGs and mortars or has it been done to death? I'm doing a write-up for IMTU.

DX

 

[Supplement Four]

I'm kind of partial to the neat sound "swisszzzz" that the laser makes as it eats up air molecules, racing through the atmosphere.

But, even though the laser itself may be silent, that doesn't mean everything associated with a laser rifle is slient. Contact with the atmosphere or impact on surfaces makes sounds.

And, let's not forget about the equipment needed to generate the laser. The laser rifle itself, not the laser, could hum or make some sort of sound. There could be a sound with the rifle turned "on", and there could be a sound when the energy for the laser is released.

So, I think it's more likely that lasers certainly do have some sounds associated with them, even if the laser itself is quiet.

 

[saundby]

Sounds off powerful lasers

Lasers, even high power ones, don't make any appreciable noise in the air, even if they interact with the dust in the air--which is typically something you want to avoid, you want the energy to go into the target, not the atmosphere.

Lab lasers are pretty well silent. Sometimes you'll get a little annoying whine off the power supply.

A really high powered laser can make some noise, mostly power supply related noise. There's a set of cyclical surges of power that can cause some microphonics in the system. The design of the laser and its power supply will determine whether it's in the audible frequency range or not. Sometimes you can get really nasty, ear-splitting whines off of mag amps or other components in the power system that resonate at audible frequencies, or at near multiples of audible frequencies.

Low frequency pulsed system can thrum or make a beating noise. With the powers being transferred, wiring, waveguides, and other components will move and beat against housings.

You can get some noise off of charge pumps as well. Pretty much the same sort of thing as the power supplies.

The beam director and focusing systems can make noise as well. If there are mechanical actuators on it, you'll hear the servos and movement of the components.

Then, when the beam reaches the target you can get noise there, too. What noise will depend on how it interacts with the target. If it's just whiffing off some paint and warming the metal to the point of failing under pressure, there won't be any appreciable noise until the blowout happens. If you pour in more energy more quickly you get the noises from the heating and failure of the target material.

 

[Supplement Four]

Lasers, even high power ones, don't make any appreciable noise in the air, even if they interact with the dust in the air--which is typically something you want to avoid, you want the energy to go into the target, not the atmosphere.

Lab lasers are pretty well silent. Sometimes you'll get a little annoying whine off the power supply.

A really high powered laser can make some noise, mostly power supply related noise.

To do the type of damge that a laser rifle does in Traveller, it'd have to be an extremely high powered laser, which means, as you allude to in the last sentence but not the first, that it just may "crack" or "zzzzt" through the atmosphere, especially if precipitation is high.

 

[Gadrin]

Thanks for the reference. For those of us without ready access to it, could you comment on what they say on noise-levels in the spirit of fair use. Noise or no noise? Where do they stand in the debate?

We must have a physicist in the room? I've done a little lidar engineering work in a previous life but only low-power.

Also on the topic of lidar, should I start a topic on personal point defense lasers(PPDL) i.e. why Imp marines laugh at RPGs and mortars or has it been done to death? I'm doing a write-up for IMTU.

DX

Pretty much what the others say:

zzzzzzzzzzzzzzzzzzzzzzzzzzzzz & sparks.

but their's is also visible light.

For traveller they also use IR and UV and x-ray lasers.

>

 

[ThunderChilde]

Also on the topic of lidar, should I start a topic on personal point defense lasers(PPDL) i.e. why Imp marines laugh at RPGs and mortars or has it been done to death? I'm doing a write-up for IMTU.

DX

Share when you do please:smirk: I am certain it will come in use at some time.

 

[ThunderChilde]

On the topic of noise, lacking the expertise shared above, the few lasers I saw all made some noise, the one made a tooth aching harmonic that was quite painful.

I am reminded of the whines of capacitance arrays for spot welders, and some high output flash devices. Not to mention the capacitor whine on the electric fence at a natural gas facility, it was tested weekly. The cycle rate and loading of some sort of a capacitor to reach the very high amplitude and frequencies of Trav lasers might be audible.

Imangine the stress of a shoot out in a dark warehouse, were you can hear the enemies lasers recharging betwen shots, much more nerve racking than a silent weapon, like the sound of racking another round into a shotgun.

Just my .02 CrImp

 

[far-trader]

...

Imagine the stress of a shoot out in a dark warehouse, were you can hear the enemies lasers recharging betwen shots, much more nerve racking than a silent weapon, like the sound of racking another round into a shotgun.

Just my .02 CrImp

I can attest to the (virtual ) reality of that

Way back in the first person shooter (we lan played it a lot) Marathon there was an energy weapon. Normal firing mode was rapid blasts of lowish power, not too scary or accurate and easy to trace back to the shooter after the first shot. The alternate firing mode was a charge buildup. Hold the trigger and the weapon starts hum/whine getting louder as the charge builds to max for a single devastating blast. The only thing scarier than hearing that sound and not seeing the shooter in the game was the ka-chunk of the shotgun being readied.

This relates to the earlier thread somewhere around here about silent weapons and suppressive fire. That is, silent weapons don't really do suppressive fire.

 

[Gadrin]

Share when you do please:smirk: I am certain it will come in use at some time.

Thanks for the reference. For those of us without ready access to it, could you comment on what they say on noise-levels in the spirit of fair use. Noise or no noise? Where do they stand in the debate?

We must have a physicist in the room? I've done a little lidar engineering work in a previous life but only low-power.

Also on the topic of lidar, should I start a topic on personal point defense lasers(PPDL) i.e. why Imp marines laugh at RPGs and mortars or has it been done to death? I'm doing a write-up for IMTU.

DX

Yeah interesting.

GURPS offers them for Traveller vehicles and in strict terms a Battlesuit/dress is built via those rules.

I'd love to see that writeup.

< Grabs T4's Emperors Arsenal and sees what that offers for Battledress >

>

 

[saundby]

To do the type of damge that a laser rifle does in Traveller, it'd have to be an extremely high powered laser, which means, as you allude to in the last sentence but not the first, that it just may "crack" or "zzzzt" through the atmosphere, especially if precipitation is high.

If its a quick burst discharge, the laser itself may make a noise like a spot welder sans the sound of the weld itself. The taarget will make the rest of the noise. If there's a lot of atmospheric interaction, you won't have time enough for a "zzzt", a bit of a bang could occur-which would normally mean you're wasting energy.

For Trav, I usually assume a weapon beam on that's invisible with a visible green, blue, or violet light available as a tracer if you turn it on. I also assume active beam focusing and adaptive optics, which means the gun auto-adjusts for atmospheric conditions such as refraction, beam scattering, blooming, and so on. A pilot beam hits the target, the calcs are performed, the main beam fires with all appropriate compensation to put the maximum amount of energy possible into the target. The main firing cycle is closed-cycle as well. I figure if we can do it on a test bench now, they'll have it commoditized and commercially available as standard by the time of the 3I.

 

[Straybow]

Pretty much what the others say:

zzzzzzzzzzzzzzzzzzzzzzzzzzzzz & sparks.

but their's is also visible light.

For traveller they also use IR and UV and x-ray lasers.

X-ray lasers are fine, except the lead shielding to protect the user from the x-ray source makes it somewhat unwieldy.

 

[wfames]

I'm a physics student, and work with lasers every day (I specialize in Atomic, Molecular, and Optical physics). None are near the power levels one would expect of a weaponized laser, but I have a good idea of the physics which would be involved.

As was mentioned previously, the laser beam itself would make no noise so long as it did not ionized the air. Whether or not that would happen would primarily be dependent on the chemical makeup of the air and the wavelength of the laser.

It seems to me that there is physical justification for pretty much every laser sound that has been proposed, and all could co-exist in the same TU, which is the way it is IMTU. Some lasers might have electronic sounds, others might have it suppressed or eliminated. Some models of laser will make glowing beams or cracking sounds if certain materials are present in the air in significant amounts. Relatively low-tech or low-quality laser guns would likely be lacking in adaptive optics (too expensive/hard to make) reducing their effectiveness at range, would have loud electronics and probably glow, crack, and lose power if used in the presence of several somewhat uncommon air contaminants due to a poor wavelength selection and a large spectral width.

On the other hand, if you have the money and technology, you can get noise-suppressed electronics, adaptive optics, including adaptive focusing, and an adjustable wavelength to eliminate any interactions with the air. Or to encourage them if that's what you want, I suppose.

Not that the beam of an x-ray laser will pretty much always be invisible and silent, as x-rays are not absorbed by atomic electrons, and nuclear interactions are highly unlikely, as the nucleus is much smaller than the whole atom.*

Also, IMTU, lasers are rarely a standard-issue combat weapon or otherwise used with any great frequency, mostly being used as stealth/sniper weapons, since the delicate optics of a laser system with adaptive optics would be damaged easily in a combat environment. And I'm not talking about just broken or shattered: at the kind of laser powers one would want to use for a laser being shot at an armored target, tiny defects can severely distort the beam, and medium size ones can lead to catastrophic failures. Even things which don't damage the lens itself can ruin the lens coatings with potentially exciting consequences.

Yeah, lasers are a pretty detailed and fully-fleshed-out weapon system IMTU. I really enjoy lasers, and my group can never have enough ways to modify and personalize their weapons, so it works out pretty well.

*I suppose for a REALLY high-powered x-ray laser, the consequences of scatterings and other such interactions could become visible. I haven't done the math, but I'm inclined to think that man-portable lasers would likely not touch such a power level.