Subwoofer (powered) necessary with Onkyo TX-8255 and Audioengine P4 speakers?

I most recently bought the Onkyo TX-8255 and Audioengine P4 speakers, and they are on their way to me via FedEx. I gave myself around a $500 budget (including stands, cables, etc.), and I already own a turntable that needs a phono input. I'll be connecting the turntable and my Apple Airport Express to it. Eventually I may also get a CD player component.

My assumption was that the P4 speakers don't need a subwoofer. However, my online searches seem to show that a lot of people like to pair them WITH a subwoofer anyway. Will I be missing them that much? I could not seem to find what is most common to do with the P4's.

I'm not sure if this matters, but most of the music I listen to is rock music and some metal. Not so much rap or hip hop (I have no desire for Beats headphones).

I realize that adding a sub means blowing my budget by $150-250 most likely, but hey, it happens.

I tried to do as much research on this before asking on here blindly. This is what I found out: The TX-8255 does not have a dedicated subwoofer output, so it looks like my only option is using a powered subwoofer (which looks like that means the connections go receiver > sub > speakers?).

Even though the TX-8255 does have "A" and "B" sets of outputs, because the P4 speakers are 4 ohm, the TX-8255 can only power one output or the other, not both at the same time. If they were 8 ohm speakers they could output at the same time.
(Not bad for a noob not having known much of anything a couple of hours ago I think. I learned quite a bit)

IHow does a powered subwoofer  compare versus if the receiver had a dedicated subwoofer out? Does it make a difference sounds-wise (like take anything away from the P4's) or is it just a matter of connection preference?

My main question is that if a subwoofer is recommended, what subwoofer would complement it the best? After all, a nice balanced sound is the goal. I hope I did not make a mistake with the receiver. I was just looking for a cheap-ish stereo receiver for music only so I could pour more money into the speakers.

I know that I will be told to of course wait to see what I think of the P4's on their own without a subwoofer, I am hoping it will sound wonderful as is. They'll be here next week. But the voice inside my head begs me to ask what advice I may be able to get on this. I haven't been able to find something this specific, so I figured I'd ask. Please excuse any ignorance shown, I tried my best at researching this on my own. Thanks!

 

P.S. - I originally lurked on this site looking for info on some headphones. That's all, innocent search. Now after going through threads and seeing pictures of people's set ups, I decided to join and get in on this hobby a bit more. Now I'm having to explain to my girlfriend why all of this equipment is coming in for the spare bedroom. 

Hi - I ended up keeping the receiver because it was within my budget. I tried using just the P4's with the receiver (no subwoofer) for about two weeks to allow for a break in period. I decided that even though I am not really much of a bass head (you won't see me with Beats headphones), they still lacked that little bit of extra "oomph" from the bass. It needed the bass to get a nicer, fuller sound. I wasn't going to be happy long term. t would definitely give them a try by themselves and decide for yourself, but I decided I needed that little bit of extra bass after all.

AudioEngine has a nice 30-day try them out return policy, and I recommend you go to their official website and look at the refurb section, they sell for $50 less than retail and come with the full warranty as if new.

Because this receiver does NOT have a dedicated subwoofer output, I had to buy a powered subwoofer. I ended up going with the BIC V1020 subwoofer. I wanted to spend around $150, and this fit within that. I bought it on Amazon. It is a 10-inch powered subwoofer for a stereo receiver.
Before buying the subwoofer, the speaker wires went from the receiver, to the P4's. 
With the subwoofer, you just need more speaker wire. It goes, Receiver to subwoofer to each p4 speaker. 

Because the P4 speakers go to about 50hz I think, I set the crossover on the powered subwoofer to about 60 hz (but experiment with this knob on the back of a powered subwoofer, as I tried going between 40 and 80hz). This means that ALL sound goes from the receiver to the subwoofer at first, but the subwoofer will only play sounds below 60hz - anything above it passes through to the speakers.

I am pleased with this solution. If I had to do it all over again, I might get a receiver with a dedicated subwoofer output and a digital input. But I am pleased with my setup. I am still in the process of breaking in the subwoofer but this is working good for me. This was not as complicated as I thought it would be, and it's what was done back in the day all the time for stereo receivers.

I find myself needing to turn the bass equalization up a little past 50% and the treble a little below 50% (with the knobs in the front of the receiver) in order to get the best sound from music. It's a little weird that I constantly have to do this depending on the album I am listening to, but they are MP3's so maybe that's why. I also have a turntable hooked up to the receiver.

Extra note: I almost went with the BIC V1220 model, a 12-inch sub instead of the 10-inch, but I stuck with the 10 because of the size of the subwoofer and because it's just in a spare bedroom of mine. BIC F12 is another 12 inch sub that was highly recommended by forums, but more for overall sound and not just music. 
Do not go with the Polk audio that's constantly on sale for around $100, I nearly pulled the trigger on it but it is just a thump rumble bass sound, not very good for music at all.

Yep, I am loving these P4's. I am really impressed at just how good the sound is. Voices seeming so life-like, the soundstage being really wide. That's definitely one part of the equation that I would not change. If I had to do it all again, who knows what receiver or sub I end up with, but I'd be sure to want to pair them up with the P4's. Really I was wanting some passive speakers and these seemed like the best bang for the buck based on reviews. I have to agree.