For two years you've been putting off buying a piano. Not because you don't want one — you do — but because you live somewhere that doesn't have a corner reserved for an instrument. Then you saw the PX-S1100. It's 102 millimeters deep. Thinner than most hardcover books. It runs on batteries. You could put it on the kitchen table and lean it against the wall when you're done. Suddenly owning a piano felt possible.
The question isn't whether the Casio is appealing. It obviously is. The question is whether you're settling. And the honest answer is: it depends on two specific things about how you live and practice.
What the slim chassis actually means
The PX-S1100 is not a compromise instrument disguised with good design. It uses a genuine Smart Scaled Hammer Action with individually weighted keys — heavier in the bass, lighter in the treble — and simulated ivory and ebony key surfaces. Both the PX-S1100 and the FP-30X offer textured key surfaces; neither skimps on key quality. The engineering challenge Casio solved is fitting that mechanism into a body 102mm deep, compared to the FP-30X's 284mm. That 18cm depth difference is the difference between fitting on a bookshelf and needing a dedicated stand.
Battery operation on 6 AA cells runs the full piano at identical performance to AC power. Sound quality, key response, and polyphony are unaffected. The batteries aren't a fallback for when you can't find an outlet — they're why you can practice at the kitchen table, move to the study after lunch, and store the piano in a closet before guests arrive.
At 11.2 kg, you can carry it with one hand. The FP-30X at 14.3 kg needs two, and its depth means it only fits on a proper stand.
The question that determines your answer: headphones
This is the most important thing in the comparison, and most articles bury it.
The FP-30X has two headphone jacks — a 3.5mm and a 6.3mm — plus Roland's Headphones 3D Ambience processing. This spatial algorithm makes the piano sound like it's in front of you rather than collapsed inside your skull. If you've ever practiced late at night with headphones and found it oddly tiring, the lack of spatial processing is usually why. The dual jacks also let you share a lesson with a teacher or a second listener, both plugged in at once.
The PX-S1100 has a single 3.5mm jack with no spatial optimization. One jack means no shared listening. No spatial processing means a narrower, more in-head experience during extended sessions.
If headphones are a regular part of your practice — because of thin walls, a sleeping household, or online lessons — this is a real daily gap between these two pianos. The FP-30X is the clear choice for a headphone-dependent player. If you mostly play through the speakers and only reach for headphones occasionally, the Casio's single jack is adequate.
The Bluetooth situation you need to know
The FP-30X includes Bluetooth Audio and Bluetooth MIDI as built-in features. Open an app, connect wirelessly in seconds, and you're playing.
The PX-S1100 has neither built-in. Bluetooth MIDI requires purchasing the WU-BT10 adapter separately — around $20–30 extra. There is no Bluetooth Audio at all, so you cannot stream music from your phone through the piano's speakers wirelessly. This is regularly discovered after purchase, not before. Factor that adapter cost into the true price if wireless app connectivity matters to you.
What the Roland keeps open that the Casio closes
The FP-30X has a line output — a stereo jack for connecting to external speakers, a recording interface, or a PA system. The PX-S1100 has no line output. For a beginner, this feels abstract today. But if you ever want to record your playing properly, connect to better speakers as your taste develops, or play for others in a larger room, the FP-30X keeps those options available. The Casio doesn't.
At the three-year mark, the FP-30X also holds up better as a listening instrument. SuperNATURAL handles note decay, velocity layers, and pedal resonance with more nuance than Casio's Morphing AiR engine — differences that become audible as your ear develops through regular playing.
Two clear verdicts for two different buyers
Buy the Casio PX-S1100 if: you have no permanent piano corner, you primarily practice through speakers rather than headphones, you don't anticipate needing line output, and the form factor is genuinely why you're finally buying an instrument. For this buyer — and there are many of them — the PX-S1100 is not a compromise. It's the correct answer. Owning a piano you'll actually play is worth more than owning the technically superior piano you'll move twice and eventually stop touching.
Buy the Roland FP-30X if: headphones are a regular part of your practice routine, you want line output for eventual recording or performance, you need built-in wireless connectivity without extra hardware, or you're prioritizing an instrument that will keep up with you as your skills grow over several years.
The Casio made piano ownership possible for people who had given up on the idea. That's not a small thing. For the right person in the right home, it's the better piano — precisely because it fits.