General Specifications
Type	Powered Bluetooth aptX HD speaker system
Amplifier Type	Class AB
Power Output	120 W peak power total (30 W RMS / 60 W peak per channel), AES
Drivers	4″ aramid fiber woofers 0.75″ silk dome tweeters
Inputs	3.5 mm stereo mini-jack USB RCA L/R Bluetooth
Outputs	RCA variable line-out 3.5 mm mini-jack headphone out
Input Voltages	110V, 60Hz 240V, 50Hz Auto Switching
SNR	>95 dB (typical A-weighted)
THD+N	<0.05% at all power settings
Crosstalk	<50 dB
Frequency Response	60 Hz-22 kHz ±1.5 dB
Input Impedence	5K ohms unbalanced
Protection	Output current limiting Thermal over-temperature Power on/off transient protection
Power Consumption	Idle: 10W
Bluetooth Specifications
Internal D/A Converter	PCM 5102
Input Bit Depth	24 bit (padded)
Bluetooth Receiver Type	Bluetooth 5.0
Supported Codecs	aptX HD aptX AAC SBC
Wireless Operation Range	Up to 100 ft (30 m) typical
Input Data Rate	Determined by Bluetooth
Wireless Latency	~30 milliseconds (ms)
Usb Specifications
Connector Type	Micro-USB
USB Device Class	USB 1.1 or above
Input Bit Depth	24 bit (padded)
Input Sample Rate	44.1 kHz 48 kHz
Headphone Amp Specifications
Headphone Amp Type	OPA2134
Full-scale Headphone Output Level	2.0 V RMS
Output Impedence	2 ohms
Recommended Headphone Impedence Level	10 ohms to 10K ohms
Weights And Measures
Dimensions	23cm Height 14cm Width 16.5cm Depth
Weight	3.3kg Left Speaker (Active) 2.4kg Right Speaker (Passive)
Total Shipping Weight	4.6kg
Shipping Box Dimensions	51cm Length 33cm Width 39cm Height
Environmental Requirements
Operating temperature	32 degrees F to 95 degrees F
Non-operating temperature	-4 degrees F to 113 degrees F
Relative humidity	5% to 95% non-condensing
Materials And Construction
	0.7″ (18 mm) thick MDF cabinets with real wood veneer  0.75″ (20 mm) silk dome tweeters with neodymium magnets  4″ (101 mm) aramid fiber woofers with advanced voice coils
Cabinets
	To minimize unwanted resonances and distortion, Audioengine cabinets have thick high-resin MDF walls with extensive internal bracing. Heavy internal sound-damping material is used to reduce unwanted sound reflections inside the cabinet. All cabinet edges are rounded which look great and reduce high-frequency diffraction effects on the front baffles. The P4 cabinet contains tuned, front-port slots.
Furniture Grade Finishes
	The HD4 cabinets are available in several handsome finishes, including walnut veneers as well as satin black paint, offering options for complementing room furnishings. Also included are detachable grills that add further aesthetic advantages as they are firmly held in place with hidden neodymium magnets for a clean look.
Custom Components
	Audioengine designs and manufactures our own tweeters, woofers, and other critical components. In other words, these are not “box built” speakers with off-the-shelf parts but custom-designed to our specifications. What we do not fabricate directly in our factory we have made to our designs (parts such as transformers, magnets, and wiring harnesses, for example). The cabinets, drivers, bass port designs, amplifiers, and crossovers are all painstakingly tuned together for each Audioengine model. This, in turn, makes for a much more efficient system that requires much less power than passive speakers and a separate integrated amplifier or similar A/V components.
Based On Studio Monitor Designs
	Studio monitor speakers are used by producers and engineers in recording and production studios. They are designed with a theoretical flat frequency response which allows the engineer to create a final mix in such a way that the recorded music will sound good on most other speakers. Although Audioengine speakers are not designed to be up-close “nearfield” studio monitors, we do carry over much of the same higher-end technology, components, and design philosophy for all Audioengine speaker systems.
Efficient Integrated Design
	The speaker cabinets, drivers, innovative bass port designs, amplifiers, and passive crossovers are all critically tuned together for each Audioengine model. This, in turn, makes for a much more efficient system that requires less power than passive speakers and a separate integrated amplifier or similar A/V components. We build all this goodness into the left speaker cabinet to make it super-easy to connect your smartphone, tablet, computer, TV, network player or any other audio product.
High-quality Bluetooth Audio
	The Bluetooth built into the HD4 powered speakers features aptX HD coding which is an advanced Bluetooth audio codec with very impressive sound. And even if your phone or tablet does not have aptX HD, the HD4 Bluetooth solution is backwards-compatible with SBC and AAC codecs, as well as standard aptX, so you can wirelessly stream music from any Bluetooth-enabled device and still enjoy all your music. High-fidelity Bluetooth aptX HD that really works and sounds great. Here is why: Extended-range wireless.  Most Bluetooth implementations have very limited range, typically within just one room. But with careful signal management circuitry and antenna tuning, we offer a superior solution that has up to 3 times the range of standard Bluetooth for multi-room use, with no degradation in audio quality. 24 bit DAC  The HD4 Bluetooth receiver and USB input both utilize the PCM 5102 DAC, widely known for its low-noise and high-fidelity. The PCM 5102 is used as an upsampling DAC and will pad all bit depths to 24 bit, achieving a higher signal-to-noise ratio and lower noise floor. Due to the high signal-to-noise specs of the PCM 5102, the fact that digital signal is upsampled to 24 bit as well as the added benefit of onboard triple redundancy power source conversion and filtering the HD4 Bluetooth implementation presents impressive low noise and low distortion characteristics with a noticeable improvement over other Bluetooth devices.
HD3 Headphone Amplifier
	The HD4 contains a high-performance headphone amplifier based on the OPA2134 low-noise opamp. This amp is able to provide low-impedance, high-fidelity audio and a 2-volt output which easily drives a wide range of headphones.
Amplifier Design
	The amplifiers in powered Audioengine speakers are located in the left speaker and are a conservatively-rated class A/B analog monoblock design. This is a more traditional speaker/amplifier configuration which provides excellent quality audio and greater flexibility. All circuit boards for the power and preamp sections are vertically mounted for maximum mechanical shock protection.
Driver Designs
	Audioengine uses audiophile-quality, ferrofluid-cooled silk dome tweeters with neodymium magnets. Silk tweeters hold up well under high power and the edge-driven design gives very smooth response. The woofers are aramid fiber woven glass composite with rubber surrounds. Aramid fiber is obviously very strong, which means the woofer retains its shape when being driven at high levels.
Shielding
	Both drivers are directly video shielded and allow the user to place the speakers within a few inches of a video monitor. This shielding also offers protection for hard-drive digital music players.