Mutually exclusive. You don't get cheap and efficient at the same time; pick what's more important to you, and build that one. The cheapest one that's at all efficient, is still not very efficient, and the most efficient one that's at all cheap, is still going to be rather expensive.
The cheapest one that's kind of (but not very) efficient is probably Etho's Practical Mob System. The most efficient one that's kind of (but still not very) cheap is probably the one from the end of JL2579's "how to build efficient mobfarms" video. Both of these can be found on YouTube. Have a look at both kinds, and see which one floats your boat.
The most efficient one that's kind of (but still not very) cheap is probably the one from the end of JL2579's "how to build efficient mobfarms" video.
With the amount of pistons, redstone, and so on that that needs I'd consider that one very expensive.
Depending on what you consider expensive, probably the most efficient and cheapest is going to turn out to be one of the shifting-floor designs (mobs spawn on upside-down slabs with tripwire above, and the tripwire triggers pistons that push the slab floor back and forth until the mobs glitch through). I personally don't like relying on glitches though.
Otherwise, for cheap yet efficient you're left with designs like Etho's which relies on mobs to wander off the spawning pads and into water channels, or designs that periodically flush the spawning pads with water to push the mobs off. The former loses potential spawn spaces to having enough channels that mobs will actually wander off and potential spawns if mobs don't happen to wander off, while the latter loses potential spawn times during the water flushes.
Someday it would be nice if someone were to do a comparison that actually controlled for number of spawnable blocks or volume of the design or something reasonable like that. Or even just a comparison that measures on the basis of "items per hour per spawnable block" rather than just "items per hour". I'd do it but I'm too lazy to actually build the different builds.
With the amount of pistons, redstone, and so on that that needs I'd consider that one very expensive.
Well yeah, that was kind of my point. Cheap ones aren't very efficient, and efficient ones aren't very cheap. You've got to pick one or the other. Can't have your cake and eat it too, you know...
If you build well away from any other mob spawning spots (128 blocks away), a simple water canal mob spawner with 4 8x8 pads gives you a mob every couple seconds.
You can build mob traps for mobs that are 2M tall by 1M wide by putting doors around a pressure plate. When the mob steps on the plate, it opens the doors. (Though due to your clever placement, the doors once in the open position, close off all sides around the mob and pressure plate.)
You can build a ton of those cheaply. They're not particularly effective, but they do work, and they're cheap.
If you build well away from any other mob spawning spots (128 blocks away), a simple water canal mob spawner with 4 8x8 pads gives you a mob every couple seconds.
A couple meaning how many, exactly?
My active-flush design averages about 1 drop every 6 seconds with an equivalently-sized spawning area (252 blocks to your 256). With 6 stacked spawning areas it gives about 1 per second.
Now an interesting comparison would be if someone were to build a JL2579 design and/or a shifting-floor design with about 256 spawning blocks so we can more directly compare the rates.
My design is only for capturing a couple mobs at a time. Like if you want to capture a skeleton for a record farm or something. But there's better ways to do that, like a pit with trapdoors level with the ground, but left in the open position with a shallow inescapable pit underneath. The mob thinks the open trap door is a solid block and walks right over it and falls in like a Wil E Coyote cartoon.
My active-flush design averages about 1 drop every 6 seconds with an equivalently-sized spawning area (252 blocks to your 256). With 6 stacked spawning areas it gives about 1 per second.
Now an interesting comparison would be if someone were to build a JL2579 design and/or a shifting-floor design with about 256 spawning blocks so we can more directly compare the rates.
Well, if two mob traps have the same continuous flat surface area, and 0 lighting, and are out of range of other mob spawning surfaces, and are at the correct distance from the player, they should be very similar in spawn rates.
So I will defer to your 1 every 6 seconds (even though subjectively it seems low to me) since I haven't done any rigorous tests.
[Edited to fix my logic below...]
Let's work the math from the wiki ...
20 spawn attempts per second x 4 mobs per spawn = max 80 per second.
Let's say our surface of 256 darkened blocks just occupies one level of one whole 16x16 chunk.
(Our chunk will always get a spawn attempt every tick because all eligible chunks do.)
There is 1/180 chance of that y-level being chosen (assuming chunk limit, lc, is 180, for player being 120 blocks above sea floor at y=40 and the spawner being 20 blocks above that.)
So the actual spawn rate should be 80 / 180 per second = about .44 per second, or avg 2.25 seconds between mobs - of course, they will come in bursts because they spawn in packs.
(0.44 per second assumes that once the location is chosen, the actual pack spawning always succeeds - it will almost always succeed in a nice flat dark area since it gets a bunch of retries to spawn 4 mobs.)
So if you're actually getting 0.17 per second and not 0.44 maybe there is some impedance?
Discontinuous surface? Light level not zero? Mob cap? Despawning before getting washed down? Don't know.
So I will defer to your 1 every 6 seconds (even though subjectively it seems low to me) since I haven't done any rigorous tests.
The canal-based method would have a higher raw spawn rate, since in the flush design any spawn attempts during the flush period will be lost since (land) mobs can't spawn in water. OTOH, the need for wandering into the canals might reduce the rate if wandering takes long enough that the cap is hit, and it may limit the ability to add additional spawning pads due to limited wandering beyond 32 blocks' distance.
FWIW, my entire farm is beyond the 32-block distance since I wanted to include Endermen and wanted to wait at the bottom of the drop.
Let's say our surface of 256 darkened blocks just occupies one level of one whole 16x16 chunk.
(Our chunk will always get a spawn attempt every tick because all eligible chunks do.)
So I will defer to your 1 every 6 seconds (even though subjectively it seems low to me) since I haven't done any rigorous tests.
The canal-based method would have a higher raw spawn rate, since in the flush design any spawn attempts during the flush period will be lost since (land) mobs can't spawn in water. OTOH, the need for wandering into the canals might reduce the rate if wandering takes long enough that the cap is hit, and it may limit the ability to add additional spawning pads due to limited wandering beyond 32 blocks' distance.
FWIW, my entire farm is beyond the 32-block distance since I wanted to include Endermen and wanted to wait at the bottom of the drop.
Let's say our surface of 256 darkened blocks just occupies one level of one whole 16x16 chunk.
(Our chunk will always get a spawn attempt every tick because all eligible chunks do.)
You might get packs from adjacent chunks too.
I haven't checked the rest of the math.
If your flush cycle is 30 seconds then given the mob half-life of 30 seconds, then about 30% of them would despawn before reaching you (if they are beyond the 32 limit and can despawn.)
Keeping an eye on Entities, it doesn't top out while I am killing mobs at my water canal spawner. Given 8x8 pads, they wander into the water quickly enough. When I visit the inside of my spawner after a killing spree, there's only about 3-4 bipedal mobs in there (and often 3-4 spiders, ha ha - they resist flushing.)
Yes, you might get some of the packs spawning from adjacent chunks, more than you would lose to adjacent chunks (due to the retry mechanism) so the actual spawn rate per chunk is probably a little higher than 0.44 per second.
The cheapest one that's kind of (but not very) efficient is probably Etho's Practical Mob System. The most efficient one that's kind of (but still not very) cheap is probably the one from the end of JL2579's "how to build efficient mobfarms" video. Both of these can be found on YouTube. Have a look at both kinds, and see which one floats your boat.
Village Mechanics: A not-so-brief guide - Update 2017! Now with 1.8 breeding mechanics! Long-overdue trading info, coming soon!
You think magic isn't real? Consider this: for every person, there is a sentence -- a series of words -- which has the power to destroy them.
With the amount of pistons, redstone, and so on that that needs I'd consider that one very expensive.
Depending on what you consider expensive, probably the most efficient and cheapest is going to turn out to be one of the shifting-floor designs (mobs spawn on upside-down slabs with tripwire above, and the tripwire triggers pistons that push the slab floor back and forth until the mobs glitch through). I personally don't like relying on glitches though.
Otherwise, for cheap yet efficient you're left with designs like Etho's which relies on mobs to wander off the spawning pads and into water channels, or designs that periodically flush the spawning pads with water to push the mobs off. The former loses potential spawn spaces to having enough channels that mobs will actually wander off and potential spawns if mobs don't happen to wander off, while the latter loses potential spawn times during the water flushes.
Someday it would be nice if someone were to do a comparison that actually controlled for number of spawnable blocks or volume of the design or something reasonable like that. Or even just a comparison that measures on the basis of "items per hour per spawnable block" rather than just "items per hour". I'd do it but I'm too lazy to actually build the different builds.
Well yeah, that was kind of my point. Cheap ones aren't very efficient, and efficient ones aren't very cheap. You've got to pick one or the other. Can't have your cake and eat it too, you know...
Village Mechanics: A not-so-brief guide - Update 2017! Now with 1.8 breeding mechanics! Long-overdue trading info, coming soon!
You think magic isn't real? Consider this: for every person, there is a sentence -- a series of words -- which has the power to destroy them.
Did you want a lot more than that? Then redstone.
You can build a ton of those cheaply. They're not particularly effective, but they do work, and they're cheap.
A couple meaning how many, exactly?
My active-flush design averages about 1 drop every 6 seconds with an equivalently-sized spawning area (252 blocks to your 256). With 6 stacked spawning areas it gives about 1 per second.
Now an interesting comparison would be if someone were to build a JL2579 design and/or a shifting-floor design with about 256 spawning blocks so we can more directly compare the rates.
It doesn't use any pistons and only uses a small amount of redstone, but still gets tons of loot.
v
Well, if two mob traps have the same continuous flat surface area, and 0 lighting, and are out of range of other mob spawning surfaces, and are at the correct distance from the player, they should be very similar in spawn rates.
So I will defer to your 1 every 6 seconds (even though subjectively it seems low to me) since I haven't done any rigorous tests.
[Edited to fix my logic below...]
Let's work the math from the wiki ...
20 spawn attempts per second x 4 mobs per spawn = max 80 per second.
Let's say our surface of 256 darkened blocks just occupies one level of one whole 16x16 chunk.
(Our chunk will always get a spawn attempt every tick because all eligible chunks do.)
There is 1/180 chance of that y-level being chosen (assuming chunk limit, lc, is 180, for player being 120 blocks above sea floor at y=40 and the spawner being 20 blocks above that.)
So the actual spawn rate should be 80 / 180 per second = about .44 per second, or avg 2.25 seconds between mobs - of course, they will come in bursts because they spawn in packs.
(0.44 per second assumes that once the location is chosen, the actual pack spawning always succeeds - it will almost always succeed in a nice flat dark area since it gets a bunch of retries to spawn 4 mobs.)
So if you're actually getting 0.17 per second and not 0.44 maybe there is some impedance?
Discontinuous surface? Light level not zero? Mob cap? Despawning before getting washed down? Don't know.
The canal-based method would have a higher raw spawn rate, since in the flush design any spawn attempts during the flush period will be lost since (land) mobs can't spawn in water. OTOH, the need for wandering into the canals might reduce the rate if wandering takes long enough that the cap is hit, and it may limit the ability to add additional spawning pads due to limited wandering beyond 32 blocks' distance.
FWIW, my entire farm is beyond the 32-block distance since I wanted to include Endermen and wanted to wait at the bottom of the drop.
You might get packs from adjacent chunks too.
I haven't checked the rest of the math.
If your flush cycle is 30 seconds then given the mob half-life of 30 seconds, then about 30% of them would despawn before reaching you (if they are beyond the 32 limit and can despawn.)
Keeping an eye on Entities, it doesn't top out while I am killing mobs at my water canal spawner. Given 8x8 pads, they wander into the water quickly enough. When I visit the inside of my spawner after a killing spree, there's only about 3-4 bipedal mobs in there (and often 3-4 spiders, ha ha - they resist flushing.)
Yes, you might get some of the packs spawning from adjacent chunks, more than you would lose to adjacent chunks (due to the retry mechanism) so the actual spawn rate per chunk is probably a little higher than 0.44 per second.