AUDIOENGINE HD6 POWERED SPEAKERS REVIEW JIM CLEMENTS SEPTEMBER 14, 2016 BOOKSHELF SPEAKERS Audioengine’s new HD6 powered speakers have flexible hook up options – analog, optical or Bluetooth. They are solidly built and impressed me with their excellent imaging, dynamic midrange and tunefull bass response. They are available in three different finish options, all of which are high quality and very stylish. These are the type of speakers one would be happy to use for the rest of their life. Highlights Audioengine HD6 Powered Speakers • Flexible input options – analog, digital and Bluetooth • Surprising bass extension • Neutral, precise midrange • Extended, albeit “polite” treble response • Incredible soundstage depth • Plenty of amplifier power for mid sized rooms • Beautiful Real Wood Finishes with excellent build quality Introduction I have always admired Audioengine because of their knack for creating high quality, affordable gear. For those who may not know, Audioengine started in the mid aughts of the 21st century and have since focused on innovative, compact powered speaker systems, stand-alone DAC’s and miscellaneous wireless applications. Their products have garnered rave reviews from consumers and the press. Their products are always high quality and high value prospects for modern music lovers. AUDIOENGINE POWERED SPEAKERS REVIEW SPECIFICATIONS DESIGN: WEIGHT: 2-Way Slot-Loaded, Powered Speakers 17.5 lbs. (Left channel/amp) and 12.5 lbs. (Right POWER: channel/passive) 50 wpc RMS DIMENSIONS: MFR: 11.75” H x 7.25” W x 10” D 50 Hz – 22 kHz, +/- 1.5dB AVAILABLE FINISHES: TWEETER: Real Cherry, Real Walnut or Satin Black Paint 1" Silk Dome MSRP (PAIR): WOOFER: $749 USD 5-1/2” Kevlar cone COMPANY: CROSSOVER FREQUENCY: Audioengine Not stated SECRETS TAGS: INPUTS: Audioengine, HD6, Powered speakers, Bluetooth, 3.5mm mini-jack, RCA L/R, digital optical (SPDIF,) Bookshelf speakers, Bookshelf Speaker Reviews 2016 Bluetooth aptX CODEC: Up to 24-bit/192 kHz sample rates This is the second formal review I have done of something made by Audioengine. My first review of an Audioengine product was in January 2015 where I reviewed the B1 Bluetooth receiver. That product impressed me so much that I nominated it for the Accessory of the Year in 2015. The HD6’s were announced a few months later in November 2015. It took a while until everything synched up so I could get a pair of HD6’s in for review. I’ve had them for a few months now and can say that, true to form for Audioengine, they are an excellent deal at only $749 a pair. Design The Audioengine HD6 speakers are mid-sized powered bookshelf speakers with a built-in DAC and Bluetooth receiver. The HD6’s are larger than the mini speakers you would normally see in most common desktop solutions for gaming and/or a computer workstations. At the same time they are much smaller than the bookshelf speakers that would typically find their way into an audiophile’s living room system. I mostly listened to them on the credenza in my office as they were maybe a smidgen too big for the desk itself. The HD6’s are very stoutly constructed, a fact evidenced by their solid weight. The amplification is all contained in the left speaker so, of course, this is the heavier speaker. I was honestly expecting the amplifier to be a lightweight Class D design largely because Audioengine, the company, is a cutting-edge component manufacturer so of course they would use the most up to date amplifier topology, right? Well, surprise – the HD6’s are powered by a pair of Class A/B monoblock power amplifiers. Audioengine says these amps have built-in linear power supplies with toroidal power transformers and are rated to deliver 50 wpc RMS (<0.05% THD+N). So that’s really cool. It’s a decent amount of power from a tried and true technology and with performance upgrades that are also known to improve the sound. But Audioengine, being who they are, didn’t stop there. No siree. They went ahead and made these speaker whole by including a built-in D1 24-bit DAC. This DAC is based on the AKM AK4396A chip. This is a high end DAC solution and means the HD6’s are capable of decoding digital signals up to 24-bit/192 kHz via the optical input! So the inclusion of a built-in high end DAC sets apart the HD6’s, right? Sorry, but Audioengine didn’t stop there. They also included a built-in B1 Bluetooth® Receiver with aptX®. The B1 features 24-bit upsampling and it is described by Audioengine in their own words, “. for Bluetooth the AK4396A is used as an upsampling DAC and will pad all bit depths to 24-bits, achieving a higher signal-to-noise ratio and lower noise floor. Due to the high signal-to-noise specs of the AK4396A, the fact that digital signal is upsampled to 24-bits – as well as the added benefit of onboard triple redundancy power source conversion and filtering – the HD6 Bluetooth implementation presents impressive low noise and low distortion characteristics with a noticeable improvement over other Bluetooth devices.” Not only does this mean that the HD6’s are highly flexible in terms of the type of signals they can accommodate, but they also handle those signals like a champ! The drivers in the HD6’s are well-designed and manufactured for the specific needs of this system. The woofers are custom 5.5” Kevlar drivers with die cast aluminum baskets. They are slot-loaded via a slotted port at the top back of each cabinet. The tweeters are custom 1” silk dome tweeters with neodymium magnets and ferrofluid-cooled voice coils that are recessed into some modest waveguides. These drivers are mounted in solidly made cabinets of ¾” (20 mm) thick MDF cabinets. There are three finish options. Two are real wood veneers with furniture-grade finishes – cherry and walnut. Or you could choose the third option, satin black paint for a more subdued look. Like I mentioned above, the amps and electronics are in the left speaker. The back panel of the plate amp has a lighted “pair” button, a detachable Bluetooth antenna, analog ins (mini plug and RCA), optical in, RCA stereo out, binding posts for speaker level out to the right speaker, a power switch and fuse protection. The front of the cabinet has a lovely aluminum accent along the bottom which also has a rotary volume control. The speakers come with a nice little solid aluminum remote control with buttons for standby, power, and volume up/down. I used the remote a lot during the review period and it was indeed a most welcome touch. The grilles are detachable and magnetic (with sufficiently strong magnets, BTW). There are also threaded inserts in the base of each cabinet that can be used to secure the speakers to a pair of stands. Set-up The first thing I did after receiving these speakers was to set them up in the big theater space to get a taste of their sound. Even fresh out of the box, the sound was rich and solid in the bass with a delicate, slightly recessed top end. I liked what I heard and when this happens, I tend to crank it up and let the sound wash over me. I quickly found the upper volume limit with the HD6’s in the big room so I knew the only way to properly evaluate these speakers would be in a smaller space. So I took them to my office. My office is about 175 square feet with a suspended acoustic ceiling. Though I have a big desk, I am an engineer which means I have lots of large format pieces of paper I need to manage so there really wasn’t enough space on the desk for the mid sized HD6’s. That’s why I placed them on the credenza in the front of the room. (If I didn’t have all the plan sheets, then they would have been on the desk, straddling my monitors.) In any event, the speakers were spaced about 6′ apart and were about 8′ from the listening position. I think this was an almost ideal geometric set up for the system considering all relevant factors. Once I found the best spot for the HD6’s, the final set up was a breeze. I connected the supplied speaker cable from the plate amp to the right speaker. I connected the optical out from an Oppo BDP 83 SE to the optical in on the DAC, installed the Bluetooth antenna, connected the power cord and then paired my PC and phone to the Audioengines. That was it. The whole set up took just a few minutes. In Use I played music over the HD6’s for several weeks before doing any critical listening. I did not hear much in the way of a transformation over this break-in period which is atypical of most speakers I review. Most speakers go through some amount of transformation when breaking in but in this case I did not hear any substantial change. (Perhaps Audioengine did a little break-in before shipping them to me?) Richard Thompson “Rumor and Sigh” Once I was ready to evaluate the sound, I put on the old Richard Thompson Rumor and Sigh CD. There is a variety of interesting instrumentation throughout this well-recorded album which makes for excellent test material. All the instruments have their own unique characteristics (and are mostly acoustic) so this CD is a very good one to use in evaluating a system.