Dual woofer? MTM? 2, 2.5, 3 ways speaker?

MTM: A Trade-Off in Speaker Design

The MTM (Mid-Tweeter-Mid) speaker configuration offers advantages as high SPL capacties, but it also comes with challenges related to vertical lobing.

This article need a good comprehension about vertical lobing.

The Lobing Issue:

Placing two woofers in an MTM design increases the distance between their acoustic centers compared to a single woofer. This larger spacing can lead to vertical lobing, causing cancellation effects at certain frequencies, particularly when listening off-axis (from the side).

Here’s an image representing the difference in vertical off-axis response between a single woofer and an MTM design:

Addressing the Issue in MTM:

While MTM presents a lobing challenge, there are ways to mitigate it:

• Lower Crossover Frequency: In MTM designs, using a lower crossover frequency for the woofers can help reduce lobing. However, this lowers the overall bass response and requires careful design considerations.

• 2.5-Way Design: If you’re set on an MTM layout, a 2.5-way crossover design can be a solution. In this design: - The bottom woofer is crossed over with the tweeter at a higher frequency. - The other woofer is crossed over at a lower frequency and compensated baffle step loss.
  This approach helps maintain a good on-axis response while minimizing lobing effects and keeping high SPL capacities.

  

Alternatives to MTM:

It’s important to consider the context when choosing a speaker configuration.

• Subwoofer Integration: If you’re using a subwoofer, the benefits of dual woofers or MTM become very less significant, even in 2.5 voices.

• Long-Range Listening with high SPL usage: For long-distance listening with high sound pressure levels (SPL), a 3-way speaker system might be more suitable, with or without subwoofer.

Conclusion:

While MTM offers dispersion benefits, it comes with lobing challenges.

Carefully consider your listening needs and explore alternative configurations like 2-way with a subwoofer or 3-way systems depending on distance and SPL requirements.

If you’re set on MTM, a 2.5-way crossover might be a solution.