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Audioengine HD6 Powered Speaker Review

Price per pair, direct from Audioengine: $749

by Wayne Myers


The HD6 is the new flagship two-way powered monitor from Audioengine. This little company out of Austin, Texas focuses on producing and delivering high performance audio products at the lowest possible cost. They offer free shipping, 30-day in-home audition (if purchased online direct from Audioengine), no sales tax, and a 3-year warranty. This is my fourth review of an Audioengine product and I was shown again that the company excels at stretching the value equation beyond normal limits.


The HD6 features RCA, Bluetooth, and Toslink inputs. The left speaker contains all of the electronics and the right speaker is passive. Each is 12 x 7 x 10 inches, very easy to place. A tiny remote gives volume, mute, and power on/off control from the Listening Position (LP). A detented, digital volume control on the left speaker has a push-push switch built in for the mute function, which quickly and smoothly ramps the volume off and on. Last Volume setting is remembered when power is turned off and back on again, even when the unit has been unplugged.

Bluetooth capability for the HD6 borrows from the B1 Bluetooth receiver from Audioengine. It features Bluetooth 4.0 aptX technology and near-CD quality sound, including 24-bit upsampling, with approximately 30 mS latency. I reviewed the B1 last year, and was very impressed by its sound quality. Using the invert-subtract-null technique for measuring fidelity, I found that the B1 actually would run for several seconds at a time with bit-perfect lossless CD quality. During the times when it was not precisely bit-perfect, it sounded like it was. After careful listening and measurement tests, I was convinced that its imitation of CD fidelity was pretty much impossible to tell from the real thing.

The HD6 optical Toslink and DAC are derived from the D1 24-bit DAC by Audioengine. This little gem has compared with honors to DACs in the over-$1,000 range, and handles 24-bit, 192 kHz sample rate natively.

The HD6 design does not include HF or LF shelving or rolloff controls like are often found on powered monitors. I never use them myself. If EQ is needed, I always find it will be more than any such simplistic control can furnish, and must accomplish it externally anyway.

RCA outputs are furnished to send signals to a subwoofer or two. Cables included with the HD6 include speaker cable from the left to the right speaker, a dual RCA interconnect, and a power cord. I received a pair of HD6 with the very handsome walnut veneer finish that would look great in any room. Cherry and satin black paint finishes are also available. Magnetic fasteners snap grille covers firmly and accurately into place. Audioengine’s signature gray plush bags with closure cords cover the speakers and cables, a classy touch included with all of the company’s products I have reviewed. Build quality appears solid and consistent. My impression has been that the team in Austin puts a high priority on their quality processes. Audioengine designs and produces their own driver elements and many of the critical components in their products, so they are anything but “box-built” with off-the-shelf components.

Link to Audioengine Web Site.


The two HD6 came together in a single double-layered carton, only weighing 33.5 pounds, It was very easy to handle. Formed foam spacers give 2 inches of Isolation all around the HD6 units inside. Each speaker comes in a plush felt bag, as do the cables.

Specifications and Measurements

  • Audioengine HD6 Specifications:
  • Power output - 150W peak power total (50W RMS, 75W peak per channel)
  • Inputs - 3.5mm mini-jack, RCA L/R, digital optical (SPDIF,) Bluetooth aptX
  • Outputs - Variable line-out w/2.0V RMS max output, 47ohm output impedance
  • Input voltages - ]115/240V, 50/60Hz manually-switchable
  • Amplifier type - Analog dual-class A/B monolithic
  • Drivers - 5.5" Kevlar woofers, 1" silk dome tweeters
  • SNR - >95dB (typical A-weighted)
  • THD+N - <0.05% at all power settings
  • Crosstalk - -50dB
  • Frequency response - 50Hz-22kHz ±1.5dB
  • Analog input impedance - 48Kohms unbalanced (mini-jack and RCA inputs)
  • Protection - Output current limiting, thermal over-temperature, power on/off transient protection, replaceable external main fuse
  • Internal D/A converter - AKM AK4396
  • Input bit depth - 24-bits upsampled
  • Bluetooth receiver type - Bluetooth 4.0 audio
  • Supported codecs - aptX, AAC, SBC
  • Wireless operation range - Up to 100ft (30m) typical
  • Input data rate - Determined by Bluetooth
  • Wireless latency - ~30 milliseconds (ms)
  • Optical Input bit depth - up to 24-bits native
  • Optical Input data rate - up to 192KS/s native
  • Speaker dimensions (HxWxD) and weight - Left speaker (powered): 11.75” (30cm) x 7.25” (18.5cm) x 10” (25cm), Weight: 17.5 lbs (8kg); Right speaker (passive): 11.75” (30cm) x 7.25” (18.5cm) x 10” (25cm), Weight: 12.5 lbs (5.5kg)
  • Shipping box - Dimensions: 17” (43cm) x 20” (51cm) x 15” (38cm), Total weight: 33.5 lbs (15kg)
  • Power consumption - Idle: 10W, Mute: 6W; Sleep: 4W


    My in-room-measured Frequency Response is quite clean, thanks to heavy-duty reflection control, as shown by a 48th-octave smoothed version. Gating the response made no improvement to these measurements. The 6th-octave smoothed version shows a slight rise toward the low frequencies, as one would expect with such an indoor measurement. Response is smooth and extended, and matching between speakers is near-perfect through most of the range, supporting the excellent SS&I performance I experienced with the HD6. Above 5 kHz the matching is less precise but still very good.

    I do not claim anechoic measurement quality, so some LF boost and differences from Audioengine’s published claims are inevitable. The point made is that response is smooth and extended and well matched between left and right through the listening range.

    Frequency Response Outdoor, another view showing smooth overall response.

    Off-axis response remains smooth and is quite respectable clear to 45 degrees.

    Harmonic Distortion for this specimen is very low, as shown at 75 dB listening level at 1 m, below 0.4% above 200 Hz, and stays below 1% at 85 dB SPL at 1 m at those frequencies.

    Impulse response shows a possible slight tendency toward stored energy in the final settle time.

    Step response gives no indication of strong resonances or of troubling overshoots or irregularities.

Review Test Equipment

Measurement Methods
  • Asus G74SX Laptop, Intel I7-2670QM @ 2.2 GHz, 16 GB DDR3 Memory, Windows 7 64-bit, Room EQ Wizard, foobar2000, Reaper DAW
  • Digital Audio Workstation, Phenom II x6 1100t @ 3.5 GHz, 16 GB DDR2 Memory, AMD Radeon HD 6670 Graphics & HDMI Media by Sapphire, Windows 7 64-bit, Room EQ Wizard, foobar2000, Reaper DAW
  • Digital Media Server, Phenom II x6 1055t @ 2.8 GHz, 8 GB DDR2 Memory, AMD Radeon HD 6450 Graphics & HDMI Media by Asus, Windows 7 64-bit, Room EQ Wizard, foobar2000, Reaper DAW
  • Audioengine D1 Premium 24-bit DAC, Courtesy Audioengine
  • Roland Quad-Capture Audio Interface
  • M-Audio Fast Track C600 Audio Interface
  • M-Audio Firewire 410 Audio Interface
  • Beyerdynamic MM1 Measurement Microphone
  • American Recorder SPL-8810 Sound Level Meter
  • OPPO PM-1 Planar-Magnetic Headphones, Courtesy OPPO, Home Theater Shack Sponsor
  • OPPO HA-1 DAC/Headphone Amplifier, Courtesy OPPO, Home Theater Shack Sponsor
  • Audioengine B1 Wireless Bluetooth 4.0 Music Receiver with aptX Codec
  • ASUS Nexus 7 Tablet (2013 version)
  • LG G3 Smartphone with aptX Codec
  • Axiom ADA-1250 4-Channel Power Amplifier, Courtesy Axiom Audio
  • Behringer A500 Reference Power Amplifier
  • Onkyo TX-SR705 Receiver
  • Emotiva Pro Airmotiv 4 Powered Studio Monitors
  • MartinLogan ESL Hybrid Electrostatic Loudspeakers
  • Polk PSW10 10-Inch 100-Watt Powered Subwoofer
  • Sony SA-WM250 8-Inch 100-Watt Powered Subwoofer
  • Bosch DLR130 Laser Distance Measurer
  • Fluke 77 Multimeter
  • P3 P4400 Kill-A-Watt Electricity Usage Monitor
  • CyberPower PP1100SW Sinewave UPS

Setup and First Impressions

It took all of 2 minutes to get the HD6 set up giving good performance, followed by 3 more minor adjustments to fine-tune. At that point, the HD6 were delivering sharp imaging and a soundstage that all but allowed the speakers themselves to disappeared. The HD6 were set up purposely so that the imaging was best sitting slightly forward in my listening chair, my ears about a foot forward from the back of the chair. Before doing this, there was a midrange hollowness which I knew was from the chair-back reflection.

Initial frequency response performance revealed and even totality with a slight emphasis in the mid-bass. Mids and highs at first seemed recessed, but I soon realized that what I was hearing was lack of annoyance, always a good quality in a loudspeaker. When called upon to produce, the HD6 do so with admirable clarity and fidelity in that range.

The silk dome tweeters produce a high end that continue in this lack-of-annoyance tradition. In my listening environment, they are being compared to a pair of MartinLogan electrostatics and amplification with a price tag about 6 times higher than the HD6, so my standard for transparency is very high. I received a good transparency showing from the modestly-priced HD6.

Source comparisons

Using the tracks My Holiday by Mindy Smith and Ain't It A Shame by the B 52's, I compared four input methods, the Toslink, RCA in from the Audioengine D1 fed by Toslink, RCA in from my LG G3 smartphone, and Bluetooth in transmitted from my LG G3. For the Bluetooth I am agreeing with the near-CD-quality claim. For the HD6 receiving Bluetooth from my smartphone, test tracks showed all the signs of being free from the hashy cymbal sounds normally accompanying compressed audio.

The Toslink and the D1 sources sounded the best to me in my particular setup, with the cleanest and most distinctive soundstage and imaging (SS&I) being the distinguishing factor that I could differentiate. Using the analog inputs from my smartphone came next, and then the Bluetooth, the last two sources having ever-so-slightly less distinctness and clarity in the presentation. Without a Direct A-B comparison, those differences would not be even noticeable I am quite sure.

The Toslink input path was used for the remaining evaluations.

Midfield Evaluation

King Crimson, The Power To Believe - Acapella, Level 5

I had just listened to these tracks at high volume on my electrostatic speakers reference speakers. The second track really starts off with a bang, and is fun at elevated volume. I purposely pushed the HD6 a little with his track to see how it would compare. The cymbals are well recorded and mixed quite forward, and offer an excellent clarity test. Of course the HD6 will not run at the same volume level, but they handled this level quite well. I find myself listening for signs of tweeters at work when evaluating speakers, and these managed to stay in character and deliver the cymbals and high frequencies with no distractions during the King Crimson track.

I made a couple of minor final position adjustments using these tracks, and ended up very pleased with the evenness of frequency response from the small cabinets and drivers. The bass was solid and even and the high frequencies were very even. A small band of emphasis in the mid-bass range was evident, but barely noticeable, probably falling well within the specified +/- 1.5 dB tolerance range for the HD6.

Civil Wars: Poison And Wine. The piano and guitar are recorded in a way that is rich with detail, as are the two vocalists in this track. The HD6 presents that detail with an easy-going clarity.

Deerhoof: Qui Dorm, Només Somia

This track is full of little percussive details and sounds. While listening to this track, it occurred to me that the best compliment I could pay the HD6 was saying how easy it was to forget they were there and just enjoy music. I have heard speakers costing far more that I could not say this about.

The rear-slotted bass reflex tuning is a common strategy for small enclosures, and works well with the HD6. It limits use close to a wall, unless a bass management crossover rolls off of the lowest frequencies sent to the HD6, but in the midfield and nearfield positions that I used for the HD6, it worked very well. Bass response down to the 50 Hz cutoff point was very smooth and reasonably tight. A rubber pad on the bottom of each speaker helps anchor it and improves the tightness of the bass when used properly (more on this). The HD6 will benefit from a subwoofer to add that last octave of low notes to one’s coverage.

Experimenting with a filter to remove that slight mid-bass boost revealed only about a 1 to 2 dB emphasis in that range, hardly worth mentioning. I was actually pleased with how well the HD6 bass response performed in my room. All tests were without subwoofer support.

Todd Rundgren: Compassion

The cymbals, tinkly bells, and dense mids from synthesizers give the tweeter a good workout with this track and a chance to listen for signs of the tweeters at work. They were very well behaved and on most tracks were easy to forget about all together. The bells and cymbals on this track came through with a solid clarity.

Muse: Supermassive Black Hole

This track started out louder than I expected it to, sending me reaching for the little HD6 remote to turn it down quickly, then I changed my mind and let it ride to see how well they would handle it. The Little HD6 That Could is what I called them now tell them after that, since they got through the track with no strain even though they were pounding quite hard.

That HD6 design is that all three input types are all active all the time, allowing the user to select source instead of having to control input switching at the HD6. This is a convenience, but forces the user to be mindful of input paths. An unused input can become noisy if one is not careful, and more than once I had the same signal coming into two paths at the same time, with slightly different delays from elsewhere in my system, causing sonic effects that were not desired in the least. A little care with inputs to ensure the unused inputs are quiet and the only one path is active at a time will be the order of the day.

Radiohead: MorningMrMagpie

That mid-bass emphasis was more evident on this track. Again the experimental 1 to 2 dB de-emphasis was all it took to tame it down.

Subterranean Homesick Alien: on this Radiohead track, guitar tones are particularly distinctive and revelatory. The HD6 with no hesitation presented those tones faithfully.

My HD6 were set up at this point slanted upward slightly with a spacer under the front of each of the speakers on the homemade stands I had in use, and when I set them down flat on the stands and added a 6 pound brick on top of each of the HD6 cabinets, I could tell the low frequency tightness improved markedly. This is not unusual for small, lightweight speakers, they just do not have the mass to sit completely still. The extra mass coupled from the stands and the added brick, held on with a square of blue poster-mounting putty, were enough to hold the enclosures a little more tightly in place, although the brick did no service to the HD6 appearance-wise. The soundstage also improved, for the same reasons no doubt, even though the listening position is even more off-axis relative to the HD6 drivers. With this new setup - surprise! - the speakers completely disappeared in the soundstage and I had no reason to change their position for any further midfield testing. The Little HD6 That Could moved at this point from the realm of being a nice little pair of speakers to that of real high-fidelity, more than I had expected from them, but not a huge surprise. Similar things have occurred in reviews of other Audioengine gear in the past. My guess is that someone on their team must be a bit OCD about insisting that their products don't just sound pretty good for the price range but sound great regardless of price. With the HD6, they have pulled it off again. Nice.

In addition to tighter bass overall, the bass guitar, kick drum, and bigger resonant drums like floor toms all became much more cohesive and natural sounding. The soundstage shifted down very slightly, but centered vocals were still even with my head level, so I found this not to be a distraction.

Final Midfield Setup
  • A = LP to Speaker Plane = 52 in
  • B = Tweeter to Tweeter = 58 in
  • C = LP to Front Wall = 99 in
  • Tweeter Height = 28 in
  • Toe-In Angle = 10 deg
  • Off-Axis LP Angle, horizontal = 15 deg
  • Off-Axis LP Angle, vertical (tweeter axis to ear) = 8 deg
  • Equal heights, level, symmetry.

Going back and listening again to previous tracks, they all improved with this new setup.

I went to an old favorite track, The Verb To Love, by Todd Rundgren, and was more than a bit transported by the cohesive and natural sound and feel of all instruments and vocals on the track. The Little HD6 That Could, DID, and did so wonderfully.

Close To The Wall

The HD6 performed very well close to the front wall (farfield), much better than I expected. Of course there was the expected big boost in bass response due to boundary reinforcement. Imaging remaining sharp and the soundstage wide, open, cohesive and natural. The natural, cohesive nature of the soundstage was what surprised me the most. Even with that big bass boost from being close to the front wall, the natural and cohesive nature of the sound of the bass guitar on Radiohead’s The Tourist really stood out. A bass guitar that sounds totally a part of the mix is not an easy achievement for a small speaker.

Gorillaz: Rhinestone Eyes, Some Kind Of Nature, the inflated base is really big on these tracks. It might be just right for those who are Super Bass Hungry but it was a bit much for me. Still, it remained reasonably well controlled.

The soundstage was shifted all the way toward the wall, and imaging remained sharp. I was once again surprised at how well the HD6 handled at the wall. On Crash Test Dummies, Mmm, Mmm, Mmm, the tonality seemed slightly hollow in the midrange, and I found a decent volume level putting some strain on the tweeter amps again, so it was not my favorite position, but under the right conditions I could see the HD6 being a good speaker to try for a close-to-the-wall situation.

Final Close-To-Wall Setup
  • A = LP to Speaker Plane = 52 in
  • B = Tweeter to Tweeter = 58 in
  • C = LP to Front Wall = 99 in
  • Tweeter Height = 28 in
  • Toe-In Angle = 10 deg
  • Off-Axis LP Angle, horizontal = 15 deg
  • Off-Axis LP Angle, vertical (tweeter axis to ear) = 8 deg
  • Equal heights, level, symmetry.


With the HD6 in a nearfield setup at my mixing station, the positioning for optimum SS&I were a little more difficult to find. This may have been in contrast to the truly superb SS&I I had experienced so easily in the midfield and farfield locations. Sweet spots tend to be tighter for nearfield setups, so speaker placement can be critical. I even gave the standard equilateral triangle arrangement with the LP on the tweeter axes, but speakers with highly directive horn-loaded tweeters are the only types that I have given good SS&I results in that arrangement. And without the well-controlled reflections supporting SS&I in the midfield - I admit to being a bit fanatical about such matters - the equivalent result might not have been achievable, but I had to try. I did finally arrive at a satisfying result, although not as impressive as in the midfield.

At an on-axis LP, on brighter, more dense tracks, I found that the extended high-frequency response was a little bright, with that peak at 4 kHz standing out slightly. They needed about a 3 dB HF shelving rolloff to suit my ears on those brighter tracks. Off-axis, where the SS&I sprang to their full liveliness, I was impressed by the the HD6 delivered a distinctness of detail in the soundstage presentation that rivaled what I have heard in speakers costing well into the four-figure range, with only an occasional "tweeter-at-work" effect in evidence, possibly resulting from some combination of elevated tweeter distortion, stored energy, and the 4 kHz peak. The effect was never pronounced and was more than likely only even noticed because my ears have been spoiled by electrostatics and expensive ribbon tweeters each costing as much as the HD6 pair, to put it all in perspective. Properly placed, I found the HD6 to excel in the nearfield as they had in the mid- and farfield arrangements, with SS&I performance worth emulating and almost unnoticeable high-frequency sacrifice from the off-axis angle.

Final Nearfield Setup
  • A = LP to Speaker Plane = 35 in
  • B = Tweeter to Tweeter = 36 in
  • C = LP to Front Wall = n.a. (> 15 ft)
  • Tweeter Height = 43 in
  • Ear Height = 44 in
  • Toe-In Angle = 16 deg
  • Off-Axis LP Angle, horizontal = 17 deg
  • Face of speaker slanted forward = 10 deg
  • Equal heights, symmetry.


Make a note: Audioengine = Super Value, they are one and the same. I will not say that the Audioengine HD6 is the only great-sounding speaker at its $749/pair price point. But I will say that for a nearfield or especially a midfield monitor operating at sane volume levels, it is a serious high-fidelity speaker that should be considered by anyone shopping in that price range and beyond.

The Audioengine team has delivered another sure winner in the HD6. My new standard review ending for Audioengine products, and certainly for the HD6: Bravo again!

Go to the Audioengine HD6 Powered Speaker Review Discussion Thread.

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