NAD C 388 Ultra Dual Amplifier vs Polk Audio Signa S4
Side-by-side comparison of features, pricing, ratings, and alternatives.
The NAD C 388 Ultra Dual Amplifier delivers 150 W per channel in a compact, Class‑D design, offering audiophile‑grade performance for both stereo and home‑theater setups. It integrates NAD’s BluOS platform, providing seamless Wi‑Fi, Ethernet, and Bluetooth connectivity for multi‑room streaming and high‑resolution playback. Its versatile I/O includes HDMI, USB, optical, coaxial, and balanced XLR, allowing you to connect a wide range of sources and drive demanding speakers with precision and low distortion.
The Polk Audio Signa S4 delivers immersive, cinematic sound to your living room through advanced Dolby Atmos technology and an included wireless subwoofer. Designed to seamlessly integrate with modern 4K and 8K TVs, it transforms everyday television viewing, movie nights, and music listening into a true surround sound experience. Featuring Polk's patented Voice Adjust technology, the sound bar ensures crystal-clear dialogue so you never miss a word. Setup is effortless with the included HDMI eARC and optical cables, allowing you to control the volume using your existing TV remote while enjoying robust, room-filling bass from the down-firing subwoofer.
- Exceptional power output with low distortion
- Comprehensive network and streaming support
- Versatile connectivity including HDMI and balanced outputs
- Robust build quality and sleek design
- Immersive Dolby Atmos height effects
- Included wireless subwoofer for deep bass
- Voice Adjust technology for clear dialogue
- Simple setup with HDMI eARC and optical cables
- Premium price point may deter casual users
- No built-in phono stage for vinyl enthusiasts
- Limited to 2 channels; not a full surround processor
- Lacks built-in smart assistant integration
- No Wi-Fi streaming support built-in
- Limited physical audio inputs beyond HDMI and optical
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The Verdict
AI-generated from listing dataThe Polk Audio Signa S4 is a ready‑to‑use Dolby Atmos soundbar with wireless subwoofer for immersive TV audio, while the NAD C 388 Ultra is a high‑power, network‑enabled stereo amp for audiophile‑grade music playback.
Key differences
- •Polk provides an all‑in‑one soundbar with built‑in Dolby Atmos and wireless subwoofer; NAD is a separate two‑channel amp without surround processing.
- •Polk’s connectivity is limited to HDMI eARC, optical, Bluetooth and aux; NAD offers Wi‑Fi, Ethernet, Bluetooth AptX, HDMI, optical, coaxial, XLR and RCA.
- •Polk targets home‑theater/movie viewers at $399; NAD targets audiophiles seeking high‑resolution streaming and balanced outputs at $1,999.
Pricing & value
Polk costs $399 versus NAD’s $1,999, offering far lower upfront expense.
Performance (audio output)
NAD delivers 150 W per channel into 8 Ω with <0.02 % THD, far more power than Polk’s unspecified soundbar output.
Build quality & durability
NAD’s 2‑year warranty and robust power supply suggest higher build quality than Polk’s 1‑year warranty.
Connectivity
NAD supports Wi‑Fi, Ethernet, Bluetooth AptX, HDMI, optical, coaxial, XLR and RCA; Polk only has HDMI eARC, optical, Bluetooth, aux, USB‑A.
Compatibility & integration
NAD integrates with BluOS, AirPlay 2, Spotify, and multi‑room apps; Polk lacks smart‑assistant or network streaming.
Warranty & support
NAD offers a 2‑year limited warranty; Polk provides a 1‑year limited warranty.
Physical footprint
Polk’s soundbar (41.3 × 2.4 × 3.7 in) and subwoofer are lighter and smaller than NAD’s 10.5 kg amp.
Choose NAD C 388 Ultra Dual Amplifier if…
Audiophiles or music‑focused users needing high‑power, high‑resolution streaming and extensive connectivity.
Choose Polk Audio Signa S4 if…
Casual movie‑watchers who want simple, immersive TV sound without high cost or complex setup.
Common questions
Is the Polk system a true surround solution?
No, it is a soundbar with Dolby Atmos height effects and a wireless subwoofer, not a multi‑channel surround processor.
Can the NAD amp drive a full home‑theater setup?
No, it is a dual‑mono (2‑channel) amplifier; it does not provide surround decoding or multi‑speaker outputs.
Which product offers network streaming?
The NAD C 388 Ultra includes Wi‑Fi, Ethernet, Bluetooth AptX and BluOS app support; the Polk Signa S4 lacks built‑in network streaming.