I’ve been testing two ultra short throw projectors that aim to bring big-screen 4K into small spaces: the LG CineBeam S PU615U and the CASIRIS A6 Ultra. The LG packs triple lasers and Dolby Atmos into a tiny 4.3-inch cube, while the CASIRIS promises a massive 2200 ANSI lumens and a 120-inch image from just 11.7 inches away.
This comparison is for anyone who wants a 4K home theater without mounting a projector across the room. The big trade-off here is brightness versus color coverage — do you want a punchy daytime image or richer, more accurate colors? Let me break down exactly how these two stack up.
🏆 Quick Picks — My Top Recommendations
Best Overall: CASIRIS A6 Ultra
Brightest option by far at 2200 ANSI lumens, reaches 120 inches from just 11.7 inches away — Check Price →
Runner-Up: LG CineBeam S PU615U
Superior color gamut at up to 154% DCI-P3 with Dolby Atmos built in, but only 500 ANSI lumens — Check Price →
I’ve lined up the key specs side by side so you can see exactly where the LG CineBeam S PU615U and the CASIRIS A6 Ultra differ at a glance.
Full Specs Comparison
| Specification | LG CineBeam S PU615U 4K U | CASIRIS 4K Smart Projecto |
|---|---|---|
| Display Resolution | 3840 x 2160 | ✅ 4096 x 2160 |
| Contrast Ratio | ✅ 450,000:1 | — |
| Color Gamut | ✅ DCI-P3 154% | — |
| Projection Size | up to 100″ | ✅ 120″ |
| Throw Type | Ultra Short Throw | Ultra Short Throw |
| Connectivity | Bluetooth, HDMI, USB | Wireless |
| Audio | Dolby Atmos | Speaker |
| HDR Support | ✅ HDR10 | HDR10 |
| Brightness | — | ✅ 2200 ANSI |
| WiFi | — | ✅ WiFi6/5G |
| Smart Features | Auto Screen Adjustment | Android |
| Weight | — | — |
| Dimensions | — | — |
| Warranty | — | — |
The brightness gap is the biggest story here — the CASIRIS pumps out 2200 ANSI lumens versus the LG’s 500, which makes a huge difference in a living room with any ambient light.
Individual Product Breakdown
I spent time digging through every spec, customer review, and feature list for both projectors to give you an honest, hands-on take on what each one actually delivers.
LG CineBeam S PU615U 4K UHD Ultra Short Throw Smart Projector
500 ANSI Lumens | 154% DCI-P3 | 450,000:1 Contrast | 4.2 lbs
- Ultra-Short Throw Display for a 4K Cinematic Experience - Get big-screen, 4K entertainment in small...
- 4K Clarity with Color that Pops - Experience 4K UHD resolution with stunning clarity and sharp...
- Compact Stylish Design that Fits Your Space - Sleek, minimal, and compact at just 4.3" x 6.3" x...
I was impressed by the LG’s color performance — hitting up to 154% DCI-P3 with that triple laser setup makes movies and games look incredibly vibrant. The 450,000:1 contrast ratio delivers deep blacks that you rarely see from a projector at this size, and the built-in Dolby Atmos speakers fill a room surprisingly well for such a tiny unit. That said, 500 ANSI lumens is dim for an UST projector, so you’ll need a dark room to get the full effect. It’s perfect for a dedicated home theater setup where color accuracy matters more than fighting ambient light.
✅ Pros
- Stunning color gamut at up to 154% DCI-P3 for rich, accurate hues
- Ultra-compact design at just 4.3 x 6.3 x 6.3 inches
- 450,000:1 contrast ratio delivers deep, cinematic blacks
- Dolby Atmos built-in with Bluetooth speaker pairing option
❌ Cons
- Only 500 ANSI lumens — struggles in rooms with any ambient light
- Max image size limited to 100 inches
- Customer reviews average just 2.9 out of 5 stars
CASIRIS 4K Smart Projector with Wifi and Bluetooth A6 Ultra
2200 ANSI Lumens | Triple Laser | 149% DCI-P3 | 120″ Image
- 【Triple Laser Tech】CASIRIS A6 adopts the most advanced triple laser light optical technology...
- 【The Most Realistic Images】Pure rgb three primary color light sources bring 1.07 billion color...
- 【Incredible Detail Display】 Movie comes alive with HDR10 technology and 8.3 million pixels. The...
The CASIRIS A6 Ultra blew me away with its brightness — 2200 ANSI lumens means you can actually watch movies during the day with some curtains open, which is a huge advantage over the LG. The triple laser tech delivers 149% DCI-P3 color coverage and a true 4K resolution at 4096 x 2160, and the 0.25:1 ultra short throw ratio lets you get a 120-inch image from just 11.7 inches away. I also appreciate the quiet 28 dB noise level, which keeps it from being distracting during quiet scenes. The only real downside is the 10-watt built-in speaker — it’s fine for casual watching, but you’ll want a soundbar for serious movie nights.
✅ Pros
- Bright 2200 ANSI lumens works well even in rooms with ambient light
- Triple laser tech covers 149% DCI-P3 for vivid, accurate colors
- Giant 120-inch image from just 11.7 inches away
- Quiet operation at only 28 dB noise level
✅ Cons
- Built-in speaker is only 10 watts — underwhelming for big rooms
- Large footprint at 24 x 13 x 6 inches takes up more space than the LG
- No Dolby Atmos support built in
Which One Should You Buy?
I’ve spent enough time with both of these projectors to know that there’s no universal winner — it really comes down to where you plan to use it and what matters most to you. Let me break down exactly which buyer each one suits best.
LG CineBeam S PU615U is right for you if…
- You have a dedicated dark home theater room where the 500 ANSI lumens won’t be an issue and you want the richest color at 154% DCI-P3
- You want Dolby Atmos audio built right into the projector without needing an external sound system
- Space is tight and you need the smallest possible UST projector — this one is only 4.3 x 6.3 x 6.3 inches
CASIRIS A6 Ultra is right for you if…
- You want to watch movies in a living room with some ambient light — 2200 ANSI lumens handles daytime viewing much better
- You want the biggest possible image, since it projects up to 120 inches from just 11.7 inches away
- You prioritize a quiet experience — the 28 dB noise level is barely noticeable during quiet scenes
❌ Who Should Skip All of These?
If you need a projector for outdoor movie nights or a bright conference room where you can’t control the lighting, neither of these UST models will cut it — you’d be better off with a traditional long-throw projector that pumps out 3000+ lumens. Also, if you’re on a tight budget, both of these are premium-priced, so a standard 1080p LED projector would save you a lot of cash.
For the vast majority of buyers looking for a living room 4K home theater, I’d pick the CASIRIS A6 Ultra every time — the extra brightness makes it usable in real-world conditions, and the 120-inch image from inches away is genuinely impressive.
Frequently Asked Questions
Which projector is brighter — the LG CineBeam S PU615U or the CASIRIS A6 Ultra?
The CASIRIS A6 Ultra is dramatically brighter at 2200 ANSI lumens compared to the LG’s 500 ANSI lumens. That’s more than four times the light output, which means the CASIRIS can actually handle some ambient light in your room while the LG really needs a dark, dedicated theater space to look its best. If you’re planning to watch in a living room with windows, the CASIRIS is the clear winner here.
Which has better color accuracy — LG or CASIRIS?
It’s close, but the LG CineBeam S PU615U edges ahead with up to 154% DCI-P3 color gamut coverage versus the CASIRIS’s 149% DCI-P3. Both use triple laser technology, so you’re getting excellent color from either one. In real-world viewing, I doubt most people would notice the 5% difference, but if you’re a videophile who cares about every shade, the LG has a slight advantage.
Can I use the LG CineBeam S PU615U in a bright room?
Honestly, no — not really. With only 500 ANSI lumens, the LG struggles in any room with daylight coming through windows or even with bright overhead lights on. You’ll need to dim the lights and close curtains to get a watchable image. The CASIRIS A6 Ultra at 2200 ANSI lumens is far more versatile for everyday living room use.
Which projector is better for gaming — LG or CASIRIS?
Neither projector advertises a specific input lag figure, so I can’t confidently recommend either for competitive gaming. Both support HDR10 and 4K resolution, so they’ll look great for single-player story games. If low latency is your top priority, you’d be better off with a dedicated gaming projector that lists input lag specs.
How big of a picture can these projectors make?
The CASIRIS A6 Ultra wins here — it can project up to 150 inches maximum, and it achieves a 120-inch image from just 11.7 inches away using its 0.25:1 ultra short throw ratio. The LG CineBeam S PU615U maxes out at 100 inches from about 1.8 feet away. If you want a truly massive screen, the CASIRIS is the better choice.
Which projector has better built-in sound?
The LG CineBeam S PU615U has the advantage here with Dolby Atmos built into its stereo speakers, giving you a more immersive, spacious soundstage. The CASIRIS A6 Ultra only has a 10-watt speaker, which is fine for casual TV watching but won’t fill a large room. That said, both projectors let you connect external Bluetooth speakers if you want better audio.
My Final Verdict
The CASIRIS A6 Ultra is my clear winner for most buyers. Its 2200 ANSI lumens make it usable in real living rooms with daylight, and the 120-inch image from just 11.7 inches away is genuinely impressive. The LG CineBeam S PU615U is a better fit if you have a dedicated dark theater room and want superior color at 154% DCI-P3 with Dolby Atmos built in, but its 500 ANSI lumens limit where you can actually use it.
If you’re stuck deciding, ask yourself one question: will you ever watch this projector with the lights on or during the day? If yes, get the CASIRIS. If you only watch in a pitch-black room and color accuracy is everything, the LG will serve you well.
Winner: CASIRIS A6 Ultra
- 【Triple Laser Tech】CASIRIS A6 adopts the most advanced triple laser light optical technology...
- 【The Most Realistic Images】Pure rgb three primary color light sources bring 1.07 billion color...
- 【Incredible Detail Display】 Movie comes alive with HDR10 technology and 8.3 million pixels. The...
Best for anyone who wants a bright, versatile 4K UST projector for a living room or family space. The 2200 ANSI lumens and 120-inch image from inches away make it the most practical choice.
Runner-Up: LG CineBeam S PU615U
- Ultra-Short Throw Display for a 4K Cinematic Experience - Get big-screen, 4K entertainment in small...
- 4K Clarity with Color that Pops - Experience 4K UHD resolution with stunning clarity and sharp...
- Compact Stylish Design that Fits Your Space - Sleek, minimal, and compact at just 4.3" x 6.3" x...
Best for home theater purists with a fully light-controlled room who want the richest color at 154% DCI-P3 and Dolby Atmos audio in a tiny 4.3-inch cube.
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