Yea, I have heard a few people emphasize the importance of a roundover. But I'm getting ready to do a subwoofer project, and I don't have a router or roundover bit, and it'll just be a pain in the ass to do a roundover. So seriously, is it going to make a noticeable difference in the sound of my subwoofer?

BTW, it's a Sound Splinter RL-P15 D2 in 265 liters w/900 watts, if that makes a difference.

check this out http://www.users.bigpond.com/bcolliso/flare-testing.htm
Do a search for thriller audio, they sell flared ports.
Any kind of flare would be better than no flare at all.

Here is that sites home page http://www.users.bigpond.com/bcolliso/

Yea, I have heard a few people emphasize the importance of a roundover. But I'm getting ready to do a subwoofer project, and I don't have a router or roundover bit, and it'll just be a pain in the ass to do a roundover. So seriously, is it going to make a noticeable difference in the sound of my subwoofer?

BTW, it's a Sound Splinter RL-P15 D2 in 265 liters w/900 watts, if that makes a difference.

People have been building subwoofers without roundovers or real flares for decades
without compromising the performance of the subwoofer, so it's fine if
you can't implement that feature. Don't lose sleep. If anything, just make
sure the port diameter is the proper size, that's a more important variable,
the roundover is just icing on the cake. Real flared ports will perform better
than roundovers and you can optimize a design by implementing a flared port
vs. not, mainly to reduce hole diameter a little bit.

I used a file on MDF and it was really easy.

the diff is microscopic, get right port size & you're good to go