Review: Acoustic Research M2 DAP

Disclaimer: I received the Acoustic Research M2 DAP from Acoustic Research, for purposes of reviewing it for Headfonia. The M2 will be returned to its owner at the conclusion of this review. The pictures in this review are property of their makers, these are not our pictures. Dale is doing this as a guest review.


When I opened the shipping box, I was presented with a nice military-grade Pelican case containing the AR-M2 and accessories (USB cable and charger). The M2 itself is similar in size to the iPhone 6, but twice as thick and twice as heavy. Given the price of the M2, one might expect high physical quality as well as great sound. You will not be disappointed. The M2 is attached to a leather or leather-like cover*, quite luxurious, with a magnetic closure. I wear an Omega Grey Side of the Moon wristwatch in solid ceramic, and the M2 has just that kind of aesthetic in my opinion. Very well made with a large and beautiful touch screen, and with all of the essential features** I’ve enjoyed with the iPhone 6 – features that in some cases aren’t available on other DAP’s (Digital Audio Players).

*) The attachment of the cover to the music player is very similar to how Oppo attached the cover to its HA-2 DAC/amp, except that since the HA-2 doesn’t have a screen, its cover does not open like the M2. I really appreciate the M2 cover design, since it’s always present and affords good protection for the screen.

**) The most important feature I rely on with the iPhone is the A to Z buttons in the music player, which allow me to jump immediately to songs that begin with ‘A’, ‘B’, ‘C’, etc., since I prefer to keep 2600-plus songs in the main playlist. The M2 has that feature, which is activated by merely scrolling the default playlist up or down a little.


You will see from the photos of the M2 the volume knob at top, the MicroUSB port, headphone jack, and line out jack at bottom, the On/Off and navigation buttons on the side, and the MicroSD card slot on the side below the navigation buttons. There is a very small image of a MicroSD card imprinted into the case just below the card slot, so the user can orient the MicroSD card correctly before inserting it into the slot. Once the card is inserted, just slide the slot cover closed.

Some of the terminology used in this business may confuse users, or may seem inconsistent or ambiguous. I’ll keep it as simple and generic as possible, so users can cross-check these terms with a quick Web search. My music test tracks are a mix of CD rips and high-res downloads, and while the advantages of high-res downloads are clear enough when played on the M2, a lot of those CD rips are much more enjoyable on the M2 than when played on the iPhone with the average portable DAC and headphone amp. Many of the less-than-stellar recordings or masterings from CD have distortions, excess noise, or bad mixing that leads to harshness and/or lack of clarity with average hi-fi gear.


In general, the smoothness of the M2’s treble makes the CD-ripped tracks more listenable. It’s not because the treble is suppressed in any way – the clarity and high-frequency/harmonic extension is readily apparent, but the M2 isn’t exaggerating the bad things with distortions of its own. For all I know, some engineer at Acoustic Research listened to the better tube amps, and somehow tuned the M2 to produce a similar smooth treble response. Then again, the sound may simply be a result of clean and tightly-spec’d electronics.

Most reviewers will describe the sound with detailed terminology that may or may not hold up under different kinds of conditions – different sources of music, different types of headphones, different amps when an external amp is connected etc. The best I can say about the M2’s midrange is that besides the usual neutrality and good soundstage, the overall sensation I get is a palpable “weight” to the music. Not weighty in the sense of enhanced bass or an altered tonality, but something akin to a very clean vinyl sound, which probably only vinyl users can relate to. Palpable is the key word, and realism is the result.


The M2 bass is well-represented by Marcus Schulz’s Mainstage. Very strong and very deep electronic bass. Massive Attack’s Angel is another goodie – a heavy background rumble with strong sharp foreground impacts. Medieval Babes’ Isabella has some heavy bass at the beginning that’s not very distinct and tends toward boomy on a lot of gear, but plays well on the M2. A really large-stage presentation is Mendelssohn’s Wedding March, from HDTracks – a pipe organ recording. If your headphone can reproduce the sound of the biggest pipes accurately, the M2 will deliver an amazing experience. The Beyer DT1770 Pro is adequate for this – the Grado PS1000e is not. The better planars should handle the big bass with aplomb.

It continues on Page 2 after the click HERE or the jump below

4.3/5 - (34 votes)


  • Reply September 27, 2016


    Hi Dale, thanks for the review.

    I am surprised that not too many reviews have been published on the AR-M2.

    Purchased it last year, and since then, it has been my primary DAP. I agree with your description on how it sound. In summary, warm, lush and smooth signature.

    I chose the AR-M2 over the AK380 and the Sony ZX2, for the following reasons:
    – vs. AK380. More Power to drive full size headphones and ability to stream music (but, unfortunately been told by AR that streaming music, bypasses the designed DAC and Amp circuitry)
    – vs. Sony ZX2. More Power to drive full size headphones

    On the other hand, the only pet peeve I have on the AR-M2 is the hiss/noise it made when plugged on my sensitive IEMs (to solve this AR is selling this adapter:, and when, the Wi-Fi is on.

    I typed “made”, since I seldom hear it now. Either because I switch off the Wi-Fi after I finish downloading the albums from the Streaming service… Or because, I lost my hearing from the hours I spend listening to music…LOL


    • Reply September 27, 2016


      thanks for the comment!

  • Reply September 27, 2016

    Barun C

    Great Article Dale. Was hoping for the written review after the video. I see you are using Nathan’s bass reference track there, nice!! Will like to read your articles more often at HFN.

    Had a few questions.

    1. How seem-less is the gapless on the M2?
    2. How long did it last with a single full charge, in terms of hours in your case?
    3. How long does it take to get to full charge?
    4. What kind of USB does it have USB 2.0 /3.0 /C ?

    Keep up the good work.

    • Reply September 27, 2016

      dale thorn

      1) I can’t offer a final judgement, as I had some issues with the cards I used. I didn’t transfer any to internal memory, so will have to test that later.
      2) I ran it down once, about 12 hours I’d guess, playing music only, no Wi-Fi or other network on. Streaming would eat up some battery power.
      3) If ran all the way down, takes several hours. By contrast, my latest-version iPod takes about one hour and iPhone 6s-plus about 2 hours. My iPad about 3 hours. So, worse than iPad, but depending on what you’re playing, a good charge-to-use ratio. Some of my amps like the Lehmann Traveler or Portaphile Micro, are much worse.
      4) The standard microUSB is compatible with my USB-2 ports, but whether it has USB-3 capability I don’t know. I have a USB-3 Macbook 12-inch, and connectors, but don’t know if I could make a reliable test.

  • Reply October 2, 2016

    Brian Carr

    Hello –

    I’d be interested to know how well the M2 compares with Questyle’s QP1R, both in terms of sound quality and general handling. Any insights?

    Many thanks,

    • Reply October 2, 2016

      dale thorn

      I won’t have that chance, but the next review here might get into that.

  • Reply October 26, 2016

    Robert Follis


    This is Robert from Acoustic Research

    Thanks for great comments SKY-BLUE – just correcting this (but, unfortunately been told by AR that streaming music, bypasses the designed DAC and Amp circuitry)

    This is inaccurate – ALL signals go though the AR-M2 DAC and AMP (how could you hear them otherwise:-) The AR Music Player signals bypass the Android OS for better sound. All other signals use the standard OS path. Best & Better.

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