Distributed Mode Loudspeaker vs Vibration Panel Technology

graystones11

Member
2020-01-22 10:40 pm
Default Distributed Mode Loudspeaker vs Vibration Panel Technology. Is there a difference?

I'm doing my best to educate myself on distributed mode loudspeakers, with the goal of building hidden, hifi quality speakers in my house, either in the form of the wall itself, or as artwork panels suspended from the ceiling or mounted on the wall.

I'm new to DIY, so forgive me for my naivitae. I originally came across DML with Tech Ingredients review of DML panel options in this informative Youtube video.

It seems these speaker work best when the panel is suspended in air and not affixed to anything. There are also expensive "invisible speakers" out there sold that are built into the drywall and use the wall as the loudspeaker. These are sometimes called "Vibration Panel Technology," I believe is the same thing, but I am not sure.

What I am unclear about is how these speaker perform well when connected to the entire wall and not suspended?

If you know of projects in which people have built DML or other speakers that either use the wall as the speaker or can be affixed to the wall or suspended like artwork, I would appreciate seeing those projects.
 

murry

Member
2021-11-12 3:28 pm
Hi all - Is there any tests or data on output levels (dBSPL)?

Has anyone done polar responses.

Are there more than one source of drivers?

Any drivers found to work better than others? Make/model/wattage?

Are there any data sheets, white papers to read.

Sounds like a fun DIY project...
 
I know what a DML is. A stiff panel driven by one or more exciters into chaos where distribution of modes yields fairly flat response. Dispersion is much different than a standard moving coil driver. A huge amount of research was done by NXT before the patents ran out.

I would say that "Vibration Panel Technology” is using a flat panel, film as the “cone” and driving it with electromagnetic motors like the magnepan, or like those in a ribbon, or a VC driven film panel like the short-lived one out of Calgary (Moray had a hand in its development, it was a project led by Mitner (now EMM).

If that is how you define the secong then they ar every different tech.

dave
 

Attachments

  • Indroduction_to_dml_Harris_et_al.pdf
    469.4 KB · Views: 63
  • C91 DML stereophonic localization.pdf
    778.2 KB · Views: 100
Is NXT still in business. Are any of their products avaiable?

NXT died out after the patents expired and they had not gotten sufficient royalties to stick around. NXT didn’t really do products just licenced the tech (like Dolby, MQA, et al). They published a huge amount of reseacrh via the AES.

The legacy carries on with the more “normal” looking derivatives we see used as midTweeters or midranges. The small format may make the nature of their dispersion usable with dymnamic drivers.

The usual NXT implementation was a retangular sheet driven by one or more exciters. Even cardboard boxes and TV screens.

dave