The DML500 and DML500A are both Distributed Mode Loudspeakers. These loudspeakers are able to produce frequencies down to about 85 Hz in frequency. Modern live and recorded musical content contains program material down to as low as even 20Hz.

When the DML500 series was designed, decisions were made to set the maximum size of the DML radiator (carbon-fiber panel) to a size that makes sense for most installations. The ultimate size of the panel determined the lower limit of the frequencies that the DML500 can produce.

While this 85 Hz point is somewhat higher than a traditional point source loudspeaker, it was quickly determined to not be an issue for one simple reason: Since the DML500 was designed for the SPL levels found in live sound, subwoofers nearly almost always required (especially at the upper end of live sound quality, which is the target usage of the DML500 series) and so subwoofers would most always be involved in these types of designs.

A DML500 can work well without a subwoofer in applications such such as a church with mostly piano and chorale musical content - all of that content will tend to exist above the 85Hz limit of the DML, and so a subwoofer would not be required in this case.