WHY the Tweeters are Offset

About the M1 Active Mk2

The M1 Active Mk2 speakers have been developed as a mirror-imaged pair with dual front mounted ports and an offset tweeter. In some applications, an extremely wide dispersion tweeter, such as used in the M1 Active Mk2, will exhibit response dips if mounted exactly on center. Wave-guide style tweeters, used in other products, purposely limit dispersion and thus can be center mounted. But as hi-end audiophile speaker companies have found, a high quality dome tweeter, offset in the cabinet toward the stereo “image center” (between the left and right speakers) will have a flatter characteristic frequency and power response. This (flat power response) more closely characterizes the way humans hear.

On a horizontal polar response curve of the M1 Active Mk2, with the cabinet placed vertically, the tweeter response at one meter stays essentially symmetrical on either side of the cabinet’s centerline. This is because the angle subtended between the cabinet-centerline-to-tweeter-centerline (.5”), and the nominal nearfield listening distance (1 meter or 39.375”), is only 1.27 degrees. Thus, acoustically speaking, the offset tweeter design has no negative effects, only the positive of smoothing the frequency response in the 2KHz-4KHz range.

In the tradition of the Alesis Superport design, which uses the energy from the back of the speaker to enhance bass performance, the M1 Active Mk2s use dual, front baffle mounted, long folded ports. The dual ports on the M1 Active Mk2 are also non-symmetrical with relation to their distances from the woofer. In developing the M1 Active Mk2, Alesis engineers determined that dual ports, offset to the outside of the stereo image center gave the most coherent and extended low bass augmentation. The ports are flared on the front baffle to provide smooth and quiet exit airflow while inside they are cut with a 45° angle and faced toward the amplifier’s internal heat sink. This arrangement aids in keeping the internal amps working at a more constant temperature. At the same time, this 45° angle increases the port’s air entry efficiency.

14	M1 Active Reference Manual

M1 Active Mk2 specifications

The Alesis M1 Active Mk2 is a well-regarded studio monitor designed for musicians, producers, and audio engineers seeking high-quality sound reproduction at an accessible price point. With a focus on delivering accurate sound and a balanced performance, the M1 Active Mk2 has become a popular choice for both home studios and professional environments.

One of the standout features of the M1 Active Mk2 is its bi-amplified design. Each speaker is powered by dedicated amplifiers that optimize the performance of the woofer and tweeter separately. This bi-amplification ensures clear and precise sound reproduction across the frequency spectrum. The 6.5-inch low-frequency driver is designed to deliver robust bass response while the 1-inch silk dome tweeter provides smooth high-frequency performance, resulting in a well-rounded audio experience.

The M1 Active Mk2 incorporates advanced technologies to enhance its performance. The monitor features a front-firing bass port that helps to minimize boundary coupling and improves the overall bass response, allowing for placement flexibility within the studio. This design reduces the risk of unwanted resonances caused by proximity to walls, ensuring accurate sound even in challenging acoustic environments.

Another important characteristic of the M1 Active Mk2 is its frequency response, which ranges from 55 Hz to 20 kHz. This wide frequency range makes it suitable for various musical genres and audio applications, enabling users to hear detailed nuances in their mixes. Additionally, the monitor is equipped with a rear-mounted EQ control, allowing users to tailor the sound to their specific acoustic space, mitigating the effects of room acoustics on playback.

Durability and design are also key aspects of the M1 Active Mk2. Its rugged enclosure is built to withstand the rigors of studio use while also providing a sleek and professional appearance. The monitors can be easily positioned on desktop surfaces or mounted on stands, making them versatile for different studio setups.

Overall, the Alesis M1 Active Mk2 stands out as a reliable and affordable option for anyone looking to improve their audio monitoring capabilities. With its bi-amplified design, advanced technologies, and customizable features, this studio monitor delivers impressive sound quality suitable for both amateur and professional recording applications. Whether mixing, mastering, or simply enjoying music, the M1 Active Mk2 is designed to deliver a true-to-source listening experience.