Page 2 - Physical Look - Hardware
If you missed out on the Audioengine HD6 because it will not fit on your desk, fear not: The Audioengine HD3 encompasses many of the features of its bigger brother in a significantly more compact package. At specified dimensions of 7" tall, 4.25" wide, and 5.5" deep, they are a little larger on all ends compared to the A2+, but the HD3 still should have no problems fitting on the desk of a common man. Meanwhile, our particular unit came in a flawless Walnut Wood Veneer finish, but if you want, you can get it in Satin Black Paint or Cherry Wood Veneer as well. In my opinion, the HD3 looks simple yet elegant, and aptly looks the part as a piece of premium audio equipment. I am also happy to see detachable speaker grilles are included. They are held on magnetically, and automatically align themselves in place like magic when put on. Of course, we can never judge acoustics by the way it looks, so let us talk about its internal construction.
From the front, both the left and right speakers look nearly identical. At the bottom is a 2.75" Kevlar woven glass aramid composite woofers with rubber surrounds, and at the top is a 3/4" ferro fluid cooled silk dome tweeter with neodymium magnets. Together, their frequency response is rated at 65Hz to 22kHz ±1.5dB, and unlike its predecessor, the A2+, you can expect a much flatter response across the spectrum. If you have a subwoofer, a bass reduction switch at the back can be selected to reduce the HD3's minimum response to 100Hz. We will talk about that in our evaluation on the next page. The use of high end materials for construction allows reduced distortion at high volumes. Signal to noise ratio is specified at >95dB, THD+N at <0.05%, and -50dB stereo crosstalk.
At the bottom, Audioengine's logo is printed on a brushed aluminum metal piece. A volume control knob is located on the left speaker, which doubles as a power switch when turned all the way counterclockwise. A tactile click allows you to know when the speakers are turned on or off. It is really nice Audioengine put the volume knob in the front rather than at the back like its predecessor. Unfortunately, it is not marked, so you cannot visually identify the volume setting. Next to it is a 3.5mm headphone output. Impressively, the Audioengine HD3 has a built-in headphone amplifier powered by Texas Instruments' OPA2134 operational amplifier that can drive something up to 10K ohms impedance. A white LED that doubles as a Bluetooth pairing button is present to indicate the wireless connection status. A bass reflex port opening slit can be seen under the brushed aluminum metal piece.
Here is a shot at the back of the Audioengine HD3 powered desktop speakers. By "powered", it means it comes with an internal amplifier. What we have here is a dual analog class AB monolithic amplifier located inside the left speaker that provides 15W RMS and 30W peak per channel. As such, the left speaker weighs -- shown in the right, as you can see in our photo above -- a little more than the right; where Audioengine specifies a weight of 4.0lbs and 3.4lbs, respectively. Power is supplied by an external power supply brick.
As you can see in our photo above, Audioengine offers an extremely generous array of input and output connectors on the HD3. The company advertises it as their "ultimate mini music system", and I have no reason to doubt this claim. On the input side, we have a 3.5mm stereo mini-jack, USB, and RCA. For my particular setup, I used the 3.5mm stereo mini-jack for input from my personal computer, since I have an Auzentech X-Fi HomeTheater HD sound card. In case you do not, the Audioengine HD3 features a Texas Instruments PCM5102 DAC -- more on this later. The RCA input is hooked up to my cable box, which I occasionally use. Like most powered computer speakers with multiple inputs I have used in the past, if multiple sources are active, the Audioengine HD3 will simply mix the signals together and output both. It would have been better if inputs are separated in my opinion. The Audioengine HD3 also features stereo line level output via a pair of RCA jacks. This allows you to send audio to other speakers using an optional wireless adapter. For most people, it will probably be used for a subwoofer, which I have done so in my setup. A bass reduction switch found here can be activated to reduce the HD3's minimum response to 100Hz to complement your subwoofer as aforementioned.
On the wireless side, Bluetooth operation depends on an external antenna, which you can see in our photo above. Personally, I find it a bit unsightly, considering it is quite easy to implement an internal antenna nowadays. However, having something like this has its advantages. For one thing, the HD3's wireless range is incredible. I can plug in my speakers on the second floor of my house, and still have reception from my phone in the basement... at the opposite side of the house. I do not believe this is an entirely realistic scenario, but a strong wireless subsystem will allow for higher consistency and more bandwidth, which in turn may translate to better sound quality and improved user experience. My only complaint is Bluetooth cannot be turned off manually, which means your neighbors can also easily connect to your HD3 wirelessly.
To start, simply hit the white LED button labeled "Pair". Protocols supported over Bluetooth include aptX, AAC, and SBC. SBC, or Subband Coding, is the default Bluetooth audio codec with reasonably good audio quality and low processing power requirements. aptX is a time domain ADPCM compression algorithm that promises "CD like quality" according to the people promoting it -- but so does MP3 at 128kbps, which, in my opinion, is quite an overused marketing term in the industry. Do not get me wrong; it is probably still an improvement compared to the standard profile, since it has a more efficient encoding algorithm and higher bitrates. In case you are asking, Apple devices does not support aptX, but many high end Android devices do, like my Nexus 9. Fortunately, for Apple users, the HD3 supports AAC as well, which communicates at about 250kbps from the source.
Inside, the digital to analog converter is a Texas Instruments PCM5102 that can sample at up to 32-bit, 384kHz with upsampling support. In practice, Audioengine advertises up to 24-bit, 48kHz input via USB. With all its digital input options -- namely, Bluetooth and USB -- a quality DAC is the key to success. Most people do not own external DACs or have anything more than integrated sound from their motherboard, and having an PCM5102 inside will allow you to digitally connect your devices to your HD3 without worrying about bottlenecking the potential of your $400 speakers.
The Audioengine HD3 is built with 18mm thick MDF cabinets. The speakers are also magnetically shielded; while non-magnetically shielded speakers will definitely not fry your hard drives anytime soon, it is something nice to have, especially being computer speakers. (Just for reference, if you ever want to damage any hard drives using magnets, you will need pretty much military grade stuff.) Our photo above shows the bottom of the HD3, which has a thin layer of foam to dampen it from the surface it resides on. This is most likely your wooden or glass desk, which can be very useful. A standard 1/4" threaded insert is present for wall mounts.
If you are familiar with home theater equipment, then the speaker connectors from the powered left speaker to the passive right speaker should not be new to you. In fact, the Audioengine HD3 uses standard 16AWG speaker wires to connect the left and right unit together. The included cable is four meters long, which should be more than enough for most people. To add a bit of classiness in a no expenses spared style, banana jacks installed on both ends of the speaker cable.
As far as power consumption is concerned, the Audioengine HD3 uses 10W of power idling. Mute reduces this figure down to 6W. Standby shuts down a few items, probably the amplifier, which reduces your power consumption down to 4W according to the manufacturer.
With all this in mind, it is now time to put the Audioengine HD3 through APH Networks' infamous subjective audio tests.
Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Hardware
3. Subjective Audio Analysis
4. Conclusion
