ADAM Audio A77X
The A77X is a 2.5-way, horizontally oriented near/midfield monitor that features dual 7" woofers for separate bass and midrange, ADAM’s proprietary X-ART tweeter, a combined power output of 250 watts, and a frequency response of 38Hz to 50kHz.
The multiple award-winning ADAM A77X is the culmination of all the innovative technology found in the AX series, plus a little extra. The unique feature of the A77X is found in the function of the two 7" woofers. Rather than simply dividing the bass and mids between them at two crossover points, both woofers act together from 38Hz to 400Hz, effectively doubling the speaker surface area for low frequencies. At 400Hz, one of the drivers fades out while the other handles the midrange from 400Hz to 3kHz. The advantage of this configuration is a significant amount of bass reproduction that obviates the need for a separate subwoofer and a clean, neutral sound in the all-important midrange, free from interference and phase cancellation. Naturally (which is a pretty good word for it), the high frequencies are handled by ADAM’s own X-ART folded ribbon tweeter, which extends the A77X frequency range up to 50kHz. The A77X is effective for nearfield and midfield monitoring.
ADAM Audio A77X—Just the Facts:
- High-end dual woofer design made affordable
- 2x 7" carbon/Rohacell/glass fiber woofers
- X-ART accelerated ribbon tweeter
- 50W/2 x 100W amplification
- Front-panel on/off switch and volume gain
- Rear-panel tweeter gain and two room-compensation shelving filters
- Frequency range from 38Hz to 50kHz
- XLR and RCA connectors
- 122dB max peak SPL per pair
- 5-year warranty (2-year plus 3-year extended)
ADAM Audio A77X—Behind the Grille
Dual-woofer design becomes affordable
In certain control rooms, it may be advisable to use a horizontally designed speaker rather than a vertical one. Until the introduction of the A77X, horizontally oriented monitors were only available in ADAM’s high-end SX series.
The game-changing is equipped with the same advanced technologies as the A7X, it, therefore, is very similar to the two-way speaker. The A77X, however, distinguishes itself by much higher, compression-free maximum sound pressure levels and dynamics. Due to its power and radiation characteristics, it also is perfectly suited for both near- and midfield monitoring.
Especially noteworthy of the A77X is the extremely wide stereo field and brilliant stereo imaging. Treble and mids are reproduced with three-dimensional realism and the lows are, as expected from a double woofer design, massive without compromising on precision.
X-ART folded ribbon tweeter technology
Like all models of the AX, the A77X features the ADAM proprietary X-ART tweeter. The “X” stands for “eXtended frequency response,” which is one of the features of Accelerating Ribbon Technology (ART) that has been drastically improved. It now extends all the way up to 50kHz. In addition, the X-ART tweeter has higher efficiency and higher maximum sound pressure levels.
How X-ART works
From its inception, ADAM Audio emerged as a major force to be reckoned with in pro audio monitoring, mainly due to its innovative folded ribbon tweeter. The ribbon tweeter is based on the Air Motion Transformer concept developed by Dr. Oskar Heil, which is a pleated diaphragm similar to the shape of bellows. From the standpoint of surface area response, a 1-inch-wide pleated diaphragm is comparable in function to an 8"-diameter cone. The folded driver acts like a point-source version of a larger driver, which inherently results in lower distortion during sound reproduction. Another property of the folded diaphragm is that its squeezing movement projects air with a speed approximately five times faster than the speed of the ribbon driver itself.
ADAM engineers took this technology and improved on it, incorporating superior geometries and materials to achieve unprecedented audio fidelity. The latest iteration of the ADAM folded ribbon tweeter is the X-ART, which explores new paths in the kinematics of moving air, resulting in a dramatic improvement in the quality of audio reproduction.
The X-ART membrane consists of a pleated diaphragm in which the folds compress or expand according to the audio signal applied to them. The result is that air is drawn in and squeezed out, like the bellows of an accordion.
The ADAM X-ART design overcomes the piston-like motion of all conventional drivers and their inevitable problems, such as narrow directivity, by achieving an improvement in air loading by a factor of 4 over conventional transducers. In addition, the X-ART tweeter’s pleated membrane avoids the typical breakup/distortion and subsequent dynamic limiting at higher frequencies found in dome and cone tweeters. Another positive result of the X-ART design is that the driving “stripes” are in direct contact with the outer air and are cooled immediately.
Diaphragm area is another important factor in determining the dynamic range of a transducer. Basically, what you see is what you get. The cone area you can see is always the acoustically active area of the loudspeaker–this is true for practically all other drive units. By folding the X-ART diaphragm into the 3rd dimension (as seen from the listener’s position) a larger foil can be used, thus increasing the acoustically effective area of the diaphragm by a factor of more than 2.5 times. This results in a higher dynamic output with extremely wide dispersion.
ADAM driver technology
While ADAM driver technology could easily be misconstrued as the clone center that gave us Han Solo’s disappointing son, it actually refers to the A77X’s two 7" carbon/Rohacell/glass fiber composite woofers, which are identical to that of the A7X (maybe some cloning is involved after all). With their large voice coils (1.5") and powerful amplifiers, they are capable of very high sound pressure levels as well as very deep bass extension. Both 7” woofers work together from 38Hz up to 400Hz, at which point, one woofer fades out and only the second woofer continues to operate in the midrange up to 3 kHz. This prevents interference and possible phase cancellation in the critical midrange.
ADAM proprietary A/B and PWM amplifiers
Each driver has its own dedicated amplifier. A 50W A/B amp is responsible for the X-ART tweeter, while the bass and mid-woofers are each driven by a 100W PWM (pulse-width modulation amp).
Custom A/B amplifier
While the X-ART tweeter’s solved certain problems associated with conical tweeter designs, its wide bandwidth up to 50kHz, though responsible for the musicality and openness of the A77X’s high-frequency response, also created a problem in terms of amplification. PWM (pulse-width modulation) amplifiers, which have become popular due to their high power efficiency and low distortion, require a low-pass filter to separate the modulation frequency (the point where power switches from the supply rails) from the audio band. It imposes a limitation on the high-frequency reproduction of the X-ART tweeter. To preserve the wide bandwidth, which in turn preserves the phase coherency and resultant realism of audio in the audible range, ADAM put considerable time and effort into creating a high-frequency power amp to allow the high-frequency tweeter to live up to its potential.
An internal bandwidth of more than 1MHz is externally limited so that the unit delivers an ultra-wide response up to 300kHz. With nothing limiting the abilities of the X-ART tweeter, the monitor has unsurpassed clarity and openness which will daze and amaze even the most jaded professional ear.
PWM custom amplifier
PWM (Pulse Width Modulation) also known as Class D amplification or switching amp technology (and mistakenly digital amplification), converts the incoming signal to a series of rectangular waveforms of equal height. The width of the rectangles varies in time and represents the musical signal. This waveform can be amplified much more simply, as the transistors are used as switches that only turn the power supply voltage on and off.
It is possible that a very fast mechanical switch could do the job, but power transistors are a better choice for the task, as such, PWM amplifiers work pretty much like conventional Class AB designs.
The main advantage of PWM amplifiers is their extremely high efficiency (>90%). As a consequence the heat to be dissipated is only one-fifth of earlier designs, leading to much lower temperatures within the amps and making the use of heat sinks unnecessary.
While PWM is highly efficient, pulse-width modulation causes signal distortion due to non-linearity of the modulation based on transient response. Usually, some form of noise-shaping filter is required to eliminate the distortion. However, that alone wasn’t good enough for ADAM engineers, who set out to develop PWM units that would perform at the leading edge of sonic quality while maintaining high efficiency. The ADAM units use a proprietary technology for both the amp and the power supply section (i.e. no more transformers) combined with state-of-the-art input and filter sections to achieve the best in multi-channel active monitoring.
The front panel includes a power switch and a control for the volume that retains the volume setting independently from the on/off switch. The rear panel features several additional controls: a gain for the high frequencies (± 4dB) and two shelf filters for high and low frequencies. To ensure greater compatibility, there are both XLR (balanced) and RCA (unbalanced) connectors.
If you’ve been looking for a dual-woofer, horizontally oriented nearfield monitor that can double as a midfield, with a wide stereo field and detailed highs that are easy on the ears, the ADAM A77X is the affordable choice. Order yours today. For more information, call or chat online with your PAD Studio Specialist.
- Tweeter: X-ART
- Velocity transform ratio: 4:1
- Equivalent diaphragm diameter: 2" / 56 mm
- Woofer: 2x 7" / 175 mm
- Woofer material: Carbon/Rohacell/glass fiber
- LF amplifier: 2x 100W RMS/150W music, type PWM
- HF amplifier: 2x 50W RMS/75W music, type A/B
- Input sensitivity: -∞ to +14dB
- Tweeter gain: ±4dB
- High shelf EQ > 5kHz: ±6dB
- Low shelf EQ < 300Hz: ±6dB
- Frequency response: 38Hz – 50kHz
- THD 90dB/1m>100Hz: ≤ 0.5%
- SPL with sine wave 100Hz-3kHz in 1m: ≥ 114dB
- peak acoustic output in 1m per pair: ≥ 122dB
- Crossover frequency: 400Hz/3kHz
- Input: XLR/RCA
- Input impedance: 30k ohm
- Magnetically shielded: N/A
- Dimensions (HWD): 9.3" x 10.9" x11" (235 x 530 x 280 mm)
- Weight: 28.2 lb. / 12.8 kg