Mackie MR6mk3 studio monitors, personal (subjective) review

Mackie did a very good job with these really nice-looking speakers with high power output, 6.5” polypropilene woofer, 1” silk-dome tweeter, both drivers being powered by separate AB class amplifiers. Inside amplifiers are made of two DMOS monolithic integrated circuits, sharing the same PCB and heatsink, able to deliver up to 40 watts/4 ohms RMS for woofer (80 watts peak) and 25 watts/8 ohms RMS for tweeter (50 watts peak). So this will do a total of 65 watts RMS per speaker, power that translates into a maximum 111 dB SPL @ 1m /pair that should be enough for most small and mid-sized studio, apartments or homes (up to 40 sq. meters).



On the front side there’s the “running man” green power light and on the rear we do have signal inputs balanced: XLR, TRS and unbalanced: same TRS but in mono config and RCA, so basically there are most common analog inputs out there and that’s a very good thing because this means versatility and usability with a lot of DACs and studio equipment. We also have the two low and high frequencies filters and the volume knob, which quite rudimentary, but it does the job after all. Power button is also there, along with fuse and mains plug.



The cabinet is made of MDF and it has 12 mm thickness on the sides and 25 mm in front. Tweeter is "incapsulated" inside an additional 10 mm MDF small cage, most likely to reduce vibrations transmited from the woofer. Inside cables are strapped and tighten together nicely, but with no fono absorbant fabric around them. Instead, there’s enough fono absorbant on the sides that should take care of bass reflections from within the cabinet.



After pluging the monitors into the power outlets and RCA cables into my DAC I’ve noticed an audible hum and also a buzz coming from both left & right speakers. It was more pronunced during the evening and night, but during the day it was somehow acceptable (could only hear it between the tracks). Anyway, this was something that needed investigated immediately, because this sounded like a ground loop to me, so unpluging both monitors from the mains and re-pluging them into a custom-made 250 VA isolation transformer created a huge smile to my face: no more buzzing sound coming from my speakers anymore! So lifting mains ground properly did helped in my case.

Now, after lifting the ground, I was having a really hard time to find some noise coming out of these good-looking studio monitors. Standing in front of both speakers I coudn't get any background noise getting out, but moving my ears as close as 25-30 cm in front of the tweeter I was able to hear some hiss, but only if room's background noise was very low. Also, while litteraly sticking my ear to the woofer I was able to hear some hum too, but besides me I'm not sure if anyone else would really stick the ear directly into the woofer to search for such a hum. Conclusion: these speakers are very quiet if there are no ground loops and decent signal cables are used, so definitely a big advantage over many other studio monitors in this price range (lot of people complain on the Internet about hiss or hum, even on monitors costing twice this price).

Wile listening ATB - Chapter One I find the bass quite powerful, if not striking, with enough punch and feel into my stomach to please me enough. It took me a while to position the speakers inside my 15 m2 bedroom, on top of the stands, at ear level and I realized that my bedroom creates a couple of spikes around 80 Hz and 125 Hz, so I notched down with -2dB those frequencies directly from foobar's parametric EQ to neutralize the sound. In my 25 m2 living room I couldn't notice these two spikes, so it must be from my bedroom, most likely because both speakers are pretty close to corners or the bedroom (will get some bass traps soon to compensate this).

Sound is full, soundstage is good, but that really depends on room size, shape and furniture installed. I find details as being a strong point of these speakers, sometimes I even felt the need to reduce with -2dB the treble from the rear button, but then I realized I'm maybe too close and upfront to the tweeters, so moving back a bit increased the space in the music and bass was also delivering even more energy, being strong, full and fast enough to hear all the instruments and drums.

While listening Katie Mahan, piano with extreme dynamics, I felt that MR6 mk3 might even be more revealing than my AKG K701 headphones. Basically, I was able to hear even the smallest vibration of air of the recording room, not just piano vibes.

After hearing a few hundreds of tracks, FLAC and DSD as well, I can say that voices are clear, trebles are accurate, bass is probably best in class for such 6.5" woofers, though some people might feel upgrading with Mackie's mk3 10" subwoofer. For the moment I'm OK with the bass, also in my 15.5 sq meters I'm not sure what a subwoofer could do (it's very hard to correctly setup a subwoofer in small rooms and filled with furniture and most of the times it might do more worse than better to the final sound).

Like all the other studio monitors in not-so-well-treated rooms, finding a good spot for auditioning to take advantage of bass reflections from the walls or furniture helps a lot. In my case, standing in front of speakers at about 1-2 meters did helped, but moving on either side or 3-4 meters in front of speakers will decrease the bass punch and will make the MR6 mk3 6.5" woofers to sound like 4" ones. Like I said before, this is going to happen with all studio monitors in small rooms, this is why auditioning speakers from different positions is a must. I was able to find a very good sound in both my living room and my bedroom, so I'm quite sure Mackie MR6 mk3 sound will please most of us looking for 6.5" powered speakers in this price range.

Like all the other studio monitors in not-so-well-treated rooms, finding a good spot for auditioning to take advantage of bass reflections from the walls or furniture helps a lot. In my case, standing in front of speakers at about 1-2 meters did helped, but moving on either side or 3-4 meters in front of speakers will decrease the bass punch and will make the MR6 mk3 6.5" woofers to sound like 4" ones. Like I said before, this is going to happen with all studio monitors in small rooms, this is why auditioning speakers from different positions is a must. I was able to find a very good sound in both my living room and my bedroom, so I'm quite sure Mackie MR6 mk3 sound will please most of us looking for 6.5" powered speakers in this price range.



The inside PCB looks decent, all parts are soldered nicely and caps are glued to PCB to not interfere with woofer’s vibrations. Same PCB is also used for both MR5mk3 and MR6mk3 speakers; this is actually written directly on the PCB.

No torroid transformer inside, instead there's a decent E+I trafo with a basic EMI shield around it. It outputs 2x16V/2A, so a total of 64VA.

There's a big bridge rectifier followed by 2x4700uF/35V @105C caps. For tone correction and low-pass/high-pass filters we have a pair of ST L7812CV/L7912CV used as power regulators.

Two reputable low-noise 100-Watts TDA7294 chips are used as power amplifiers, one for each driver: woofer & tweeter. These chips are well-known on most Hi-Fi forums and I consider a great advantage to use them inside these speakers. Also, some people would say that A/B class amplifiers might have a lower-noise and a better overall output sound than class-D amplifiers (I also agree with this one too). The two power chips are using rather a low voltage, so output power would be much lower than 100 W advertised, but should be enough to drive these speakers to enough dB. Anyway, based on TDA7294 datasheet and looking to the transformer output voltage from inside MR6mk3, I'd say that Mackie's output numbers could only be achieved with a THD of 10%. For a THD of 0.5% I would approximate an output power of about 30W for woofer and 18W for tweeter, still more than enough for my bedroom and good enough for my living.



Well, no Silmic, no Nichicon, no Rybycon, no ELNA, no PANASONIC, no VISHAY, no WIMA, no SANYO, no NIPPON CHEMI-CON caps inside, just some caps branded "Cap-top" polarized caps and not-labeled non-polarized caps. I was not even able to find any datasheet or manufacturer name on the Internet about them. Well, at least they're rated at 105C...hope they'll last for a couple of years, though they're half the size of other caps rated the same capacitance and voltage (perhaps ripple current would be different).



The 6 x ST4558 opamps from inside just "made my day"; same opamps are used in many low & mid priced audio equipment like Genius, M-Audio, EMI, Logitech, but also in KRK, JBL etc. Is it so complicated to get some decent opamps like NJM5532 (very cheap actually) or NJM2114D or LM4562 that are cheap enough and generally accepted (read as: tolerated) by most audiophiles out there in mid-priced Hi-Fi equipment? Not even dare asking for MUSES 8820 or above this price, of course, but perhaps manufacturers did tested these ST/MC 4558 opamps and considered they're a good wire with gain to use inside these speakers, so please take this paragraph with a grain of salt (or just ignore it).

Measurement tests for the original NJR/JRC 4558 opamp and also for many others could be found here.
Opinions about the original NJM4558 could also be read here.

Some specs of the ST4558's datasheet (this is the improved version of the original NJM4558, at least comparing the specs):
- Unity/Gain bandwidth: 2.8/5.5 MHz
- Slew rate: 2.2 V/uS
- Noise: 12nV/SqrHz
- THD: 0.008%

Please, do understand that I'm not happy about no-name or very low-price and low-quality electronic parts, especially electrolytic caps like: ChengX, Yihcon, KYS, Top-Cap etc. (see Capacitor plague) because I've seen caps blowing away inside amplifiers and I'm also spoiled by the audiophile community forums, but also because I'm a DIY-er that knows something about electronics and about the lifespan of low-quality capacitors, especially when used in power supplies. Even KRK Rockit is using low quality caps in their low-priced monitors and results were shown here:
- M-Audio BX5 D2 - Custom PC Review & Mr. Ives
- ADAM A7X - Gearslutz and the cheap and bad quality caps is using inside.
- KRK Rokit 5 - Gearslutz
- KRK Rokit 6 - Cakewalk forum
- KRK Rokit RP8 - KVR Audio, Gearslutz, FiveFish (not quite caps related, but still interested reading on all 10 pages)
- Mackie MR8 - Youtube

Despite my picky opinion about the electronic components from inside the cabinet, these speakers do sound good indeed, so I can recommend them for their price, especially that Mackie is a respectable brand in this market and totally deserves our confidence. I would probably rate them 4.5 stars out of 5 for their look and sound without hesitation, because they sound neutral and revealing with enough bass for 6.5" woofers.

Some of tracks/albums listened:

• Dire Straits - Communique
• Pink Floyd - Dark Side Of The Moon
• ERA - The Very Best
• Fone/Native DSD - Natural Jazz Recording
• ATB - Distant Earth
• Ayre - Katie Mahan Collection
• Chesky - Best of Classics and Jazz and Audiophile Test
• Head-Fi And HDtracks - 2010 - Open Your Ears
• Manley Lab - Headphones Test Disc
• BBC - Legendary Sound LS3/5A
• The Nordic Sound - 2L Audiophile Reference Recordings
• ABC Special Sampler - Ultimate Demo Disc
• Michael Jackson - Dangerous
• Michael Jackson - Blood On The Dance Floor
• Michael Jackson - Michael
• Michael Jackson - Off The Wall
• Musique d'abord - PACHEBEL (Canon & Gigue Chamber Works)
• Various Artists - Cafe del Mar XXII
• Various Artists - Pure 80s
• Various Artists - The Rough Guide To Ethiopian Jazz
• Various Artists - Hit Zone no. 538, Best Of 2016

Note 1: In case you’re trying to lift the ground by removing the ground pin of your mains plug, just don’t do it! Mains ground is directly connected to the aluminum backplate where all the audio connectors are installed, so lifting the ground improperly may cause injuries or even death when touching audio cables or rear backplate of the speakers! So, either you use an isolation transformer, either use dedicated ground-loop removal devices with diodes, resistors and capacitors inside, but don’t lift directly the ground from the plug or from the outlet!

Note 2: One speaker is making a "pop" noise about 5" after powering off, right after capacitors get discharged; on powering on is silent. The other speaker is completely silent on both power on & off. Either workmanship, either Q&A, either some components are having a different value than suggested on original schematic (or high tolerance values).