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Alesis M1Active 620 Studio Monitors

There’s an old proverb that goes something like, “It takes three generations to make a gentleman.”

There’s an old proverb that goes something like, “It takes three generations to make a gentleman.” While that thought may be debatable within its intended context, it surprisingly applies to the Alesis M1 Active Series of studio monitors, currently in its third generation through the development of the M1Active 520 and M1Active 620 ($599 per pair). I recently had the opportunity to use the M1Active 620 pair —a 100-watt, biamplified monitor with a 6.5-inch woofer and 1-inch dome tweeter —and I was pleased to find a much more refined, cultured, and —yes —gentlemanly performer than its low price tag naturally infers.

According to Alesis, both the M1Active 520 (a 75-watt, 5-inch woofer/3/4-inch tweeter version) and the M1Active 650 benefit from a new driver design as well as precision-crafted crossovers. Whatever it is, it seems to allow for a notable improvement over previous Alesis monitor models; that isn’t an insult to the old generation, but the new generation has taken on its pedigree’s attributes, possibly shed a few of its negatives, and introduced a bevy of qualities all its own.

FAST FACTSApplications

Studio, broadcast, post production

Key Features

Two-way; 6.5-inch woofer; 1-inch dome tweeter; 100 watt biamplified monitoring; adjustable EQ settings


$599 per pair


Alesis | 401-658-5760



• Good sound

• Comprehensive frequency adjustment

• Ample power for closefield (and ‘bigger’ use)

• Low price


• Can be a bit bright at times or “low-mid dense” in thick arrangements, although EQ adjustment via the rear panel overcame most perceived issues


A good choice for a wide variety of users who need an inexpensive yet nice-sounding powered monitor.


Alesis M1 Active 620 Powered Speaker

Bench Measurement Data

AC line current, power switch off

11.5W, 0.19A

AC line current, power switch on

11.8W, 0.20A

Frequency response

(reference condition, see below)

+/- 5 dB 100 Hz – 20 kHz

Distortion 40 – 200 Hz at 95 dB spl < 10%

It also doesn’t hurt that the M1Active 620 looks very cool. Remember the sorta-amateurish-looking Alesis Monitor One? Well, the 620 looks sleek and totally pro in comparison (if it matters). Sure, the visual aesthetics of audio gear is generally inconsequential, but engineers who regularly host in-studio clients can attest to a standing fascination among creative-types of visually striking things with interestingly illuminated features, so maybe it does matter to some extent.


The two-way M1Active 620 encloses its drivers, amplifier, and various other components within a magnetically shielded wood/fiberboard encasement featuring a thick and nearly scratchproof matte black finish. Cabinet width/height/depth dimensions measure 6.5 inches x 10.5 inches x 7.75 inches. A 620 weighs 13 pounds.

Main features of the 620 as touted by Alesis include 100-watt amplification, a 56 Hz – 20 kHz frequency response, a 2.8 kHz crossover frequency, signal-to-noise ratio of >100 dB below full output unweighted, input impedance of 20 ohms balanced or 10 kohms unbalanced, and input sensitivity specs as follows: 85 mV noise (pink) produces 90 dBA output SPL at one meter and “the gain knob turned fully clockwise (maximum).” For more specs and to see how the 620 pair that I used performed under close technical scrutiny, please see the corresponding bench test.

On its face, the 620 offers a centrally placed woofer —measuring 6.5 inches and made of lightweight, shielded polypropylene with a rubber surround and high-power voice coil —secured by six screws and, above it, a centrally placed tweeter —a shielded silk dome measuring 1-inch. A metallic gray-finished insert (made of the same material as the cabinet) surrounds the tweeter and curves up, ever gracefully, to also surround an illuminated power-up button and clip light. Encircling the press/depress power button and extending south for about an inch in vertical length, the clip light glows blue upon power-up and will turn red if/when the 620 overloads.

On its rear panel, the 620 offers a bass port measuring approximately two inches across and is mounted directly behind the tweeter. Below it are two inputs —a balanced XLR and balanced TRS —and several means of level and frequency manipulation: a small black gain knob with unmarked hash marks for measurement and three three-position and one two-position toggle switches labeled Bass Density (0, 1/2 and 1/4), Hi Boost (+, 0 and -), Mid Boost (+ and 0), and Lo 3 dB (56, 80, and 100), respectively. An AC voltage selector (switching between 100V – 120V and 220V – 240V power) and a power cable input rounds out the speaker’s rear.

According to the user’s manual, the Bass Density adjustment is referred to as the Acoustic Space Switch and “compensates for placement near walls and corners.” A tutorial section for the switch is included in the manual, which recommends the flat “0” setting for control rooms offering three or more feet between speaker and wall, “1/2” (called ‘2’) for speakers positioned against a wall, and “1/4” (called ‘4’) for speakers positioned in a corner. “1/2” is for “half-space,” and compensation is made for bass boosted due to the speakers proximity to one wall; “1/4” is for “quarter-space” and compensates for two nearby walls.

Hi Boost engages a 2 dB shelving filter starting at 3 kHz that boosts with “+,” cuts with “-,“ and bypasses at “0.” Manual direction is given regarding these settings, which essentially says to boost in dead environments, cut in reflective ones, and —hopefully —leave it at “0” if all’s well. Mid boost provides an off/on for a 2.5 dB wideband midrange boost at 1.8 kHz, and Lo allows 3 dB rolloff at 56 Hz, 80 Hz or 100 Hz for use with subwoofers or to experience a smaller “radio” sound. With no sub in the mix, the toggle is suggested to be positioned at the lowest setting, 56 Hz.

In Use

I was able to use the M1Active 620s in three varied environments: a large, well-balanced control room with a plethora of wood-trimmed accoutrements, a small and fairly dead DAW-based editing/overdub room with a close front wall, and a smallish, wide-but-shallow control room alongside some great and similarly-sized monitors (Tannoy and Genelec models, both of which are priced considerably higher than the 620 pair). Further, the wide/shallow space had a recessed control-to-studio window located in front of the console, which — when the monitors were placed appropriately —acted much as “corner monitor placement” would.

All in all, I was able to hear the 620 pair in areas that were complimented by the Bass Density settings, which — as the long audition continued — progressively sold me on their acoustic flexibility. In the “corner-ish” setting, the “quarter-space” Bass Density setting performed as advertised, as did the “half-space” setting in the DAW room. As a matter of fact, I dared to tweak both levels and EQ in the DAW room —most certainly the worst sounding room of all three —and, surprisingly, the changes held up in the big room, where I naturally felt most comfortable (and where the 620 pair ran flat). Later, upon listening back to a trusted pair of monitors and frequently referenced pair of AKG cans, the tweaks continued to be cool.

I toyed with Hi Boost in all three rooms, which offered somewhat pleasing help in both the DAW and wide/shallow control room. It was a bit much in the big, well-balanced room, which —again —proved the 620 to perform as sold. Enacting “-“ on Hi Boost also worked in the bigger room, and in doing so, reminded me a bit of a set of KRKs I had used in the past (which were, again, considerably more expensive than a 620 pair).

But enough with switching toggles: how did the M1Active 620 monitors sound in each state at the most ideal setting? Pretty damn good. In most cases, mixes, raw tracks, treated vocal tracks on solo, and much more all sounded as I had remembered them on other sources. Reverb tails on vocals were vivid, both steel and nylon string acoustics felt right, and nothing alien stuck out within a variety of intimately familiar mixes. If I had to complain, at times low-mids seemed overly dense in thick arrangements and some cymbals’ transients struck me as just a tad sizzly. But that’s a conclusion I came to while A/Bing against far pricier monitors.

Further, the more I thought about how comparatively cheap they are, the better they sounded to me. Does that make me a cheapo? I don’t think so, but I do pride myself in finding a bargain and I was psyched that I didn’t even have to search for this one —it arrived right on my doorstep! Yes, product reviews can be a lot of fun!


With a price of $599 per pair, the M1Active 620 should be a hit for Alesis. It might have taken the company three generations to make a “gentleman” of a monitor, but as far as I’m concerned, it was worth the wait. Whether you’re a pro with a need for a decent secondary reference monitor or a cash-strapped self-recordist who needs the best he can afford —the newest generation of Alesis powered monitors should fit the bill.

While I can’t officially vouch for the M1Active 520, I can’t imagine that it strays far from its sibling’s performance. But —as always with pro audio gear and especially with monitors — you should grab a 520/620 pair from a store near you (or order a pair from a retailer with a generous return policy, just in case) and listen to them yourself. If you need them, I’ll bet you keep them.

Strother Bullins is Reviews and Features Editor for Pro Audio Review.

Bench Measurement COMMENTARY

The frequency response and changes in response with the back panel controls were measured with my MLSSA system indoors. A combination of what is called the “quasi-anechoic” response and the near field response of the woofer system (driver and port) is made to create the overall effective anechoic response of the speaker. In my relatively high ceiling sound room, I mount the speaker under test on a stool and tip the front surface up perhaps 30 degrees. This allows the measuring microphone to be placed roughly half way between the floor and ceiling to get the longest path length of the floor and ceiling reflections that takes the quasi-anechoic response down to about 250 Hz. The measuring microphone was placed 1M away and perpendicular to the front panel of the speaker midway between the woofer and tweeter.

Figure 1 is the overall equivalent anechoic response of the speaker with the rear panel controls set to what I called the “reference” condition. This is with the acoustic space set for 0 or full space, high frequency boost set to 0, the mid frequency set to 0, and low frequency cut set to 56 Hz, the lowest position. As can be seen, the response relative to the 400-700 Hz range has boosted lower and higher frequencies. This overall shape was verified by a full frequency third-octave smoothed response under these same conditions but letting in room reflections and the outdoor response I took when measuring low frequency distortion. Still, one could say from the figure that the response is about +/- 5 dB from 100 Hz to 20 kHz. I set the speakers up on either side of one of my computers in what would be a free space condition and thought the overall sound was quite good on MP3 played back files with the bass not seeming to be excessive. I did think that the sound was better with the high frequency switch to the minus position. One could ameliorate what could be considered excessive bass by cutting off the response with the high pass switch and/or using a subwoofer to handle the bass frequencies.

The effect of the rear panel controls was essentially all above 300 Hz so the remaining response figures are from 300 Hz upwards. Figure 2 shows the effect of horizontal off axis response for 15 and 30 degrees. Figure 3 illustrates the effect of the acoustic space switch for 0 (reference) and 1/2 and 1/4 space positions. Oddly, the way less relative bass is obtained in the 1/2 and 1/4 space positions is to increase the amplitude of the mid and higher frequencies rather than to leave them alone and reduce the bass level. Figure 4 plots the change in response with the high frequency control placed in the – and + positions relative to the reference 0 position. Finally, Figure 5 shows the effect of the mid range boost position relative to the reference.

I then set the speaker up outside in my back yard to measure low frequency distortion. The microphone was set 1M away aimed at the woofer. Since the dominant harmonics of distortion in woofers is second and third, I set my Audio Precision SYS2722 to measure the second and third harmonics as a function of frequency over a range of 40 Hz to 200 Hz. The tracking bandpass filters in this test reduce the effects of extraneous wind and other noises. Never the less, it was hard to measure any appreciable distortion at levels below 85 dB or so. Figure 6 is a plot of the second and third harmonics vs. frequency at a constant 90 dB spl. The Audio Precision is handy for this as it can regulate the generator output level so as to maintain a selected variable to be constant, in this case the microphone output level for 90 dB. At a level of 94 dB spl, distortion has increased with the third harmonic at about 7% at 170 Hz and at 100 dB, things were clipping and distortion is way more than 10%. From this, the speaker is reasonable for low frequency distortion up to about 94-95 dB spl.

– Bascom King