Lol... You're comparing two models of totally different price point and performance. If you have the budget, go all the way to S730 xD Poisonous! Other questions let others give comments as i don't own them. But audition at lowyat tells me that S730 is totally awesome and is freaking. Shake your room with that baby!! Mids and Highs are also  awesome to me. More than sufficient bass to hit your heart. haha

im a c3 user too. s730 can provide more bass than you ever need. even s530 is pretty awesome..heck even s330 give more bass than c3

s730 is awesome, the bass can shake your room

i like the mid and high of my c3, you may try upgrade your sound card first see if you like it

u sure u wanna compare this two?

okays

S730 got ridiculous (good) bass so loud that it just felt like your lungs being sucked into the subwoofer if played loud compared to your C3

but S730 woofer ain't that accurate compared to your C3 because 10" subwoofer is huge and heavy (and slow) compared to 8"

says people the midrange for this S730 is slightly laid back and the subwoofer just covers the whole thing up (trebles could be better tho)

I suggest you skip to S730 if you want better overall sound than C3. then next time, you can add soundcard to boost the performance... the only drawback is the super heavy and big 10" subwoofer. if you have small room then it wouldn't be at its max potential.

c5 came with radio.

asus xonar DS

Top up to S730 

Asus Xonar DS costs around RM249, or you can try out Creative Sound Blaster X-Fi Surround 5.1 Pro USB cost around RM239. Not so sure about Asus Xonar DS, but it uses Wolfson DAC which I like the sound compare to other DAC. Creative X-Fi 5.1 USB used Cirrus Logic DAC tend to have a bit of grinding treble to me.

@FaezFarhan

after getting the S530D you might wanna do a slight mod inside the subwoofer.
you need to line the walls of the subwoofer with some stuffing cuz I realize that the subwoofer do ring a little.(to me it's a huge bug for bass)
pillow stuffing,aquarium filter,or any spongy material you can find that absorbs sound.

one last thing, since this is a ported subwoofer, the channel from the speaker to the port must run freely and never let the stuffing restricts the air flow

Means ventilation around the bass reflex port must be good, not blocking it to SUCK and PUMP air xD

just don't let the stuffing covering the tube/port
or not you'll stress the subwoofer speaker or cause unwanted internal vibrations

aquarium filter works but I'm not sure cuz I haven't try it yet.
I know the Edifier S530D satellites do have a good amount of those filter inside it

I've once threw a pillow in my S530D subwoofer and it works like charm. no more annoying ring ring sound
but have to take it out cuz I want that pillow  
got the pillow idea from music stores that sells drums
some also had egg cartons inside their subwoofers, you can try that too

you can get the xonar DS for rm189 from lingloong 

https://forum.lowyat.net/topic/864367

only if your soundcard sucks badly then optical might have great improvements over ordinary analog input.

but if your soundcard is awesome and you try optical, you might hear a downgrade

sponsor me
that just add noise ==

I have just enough to line the walls of the subwoofer.
I suppose one layer? but I got excess so I just stuff all in making it 1 and a half