Close
0%
0%

xctr

surface transducer-driven portable loudspeaker

Similar projects worth following
102 views
0 followers
Purpose:
Experiment with surface transducers (speaker exciters, distributed mode loudspeakers) in portable loudspeaker format; possibly spread it to the general Hacker community (expanding from DIY home audio scene, its natural habitat).

Brief Intro to Surface Transducers

Distributed Mode Speakers - Wikipedia

Surface transducers are a type of audio transducer (the likes of speakers, bone conduction devices, etc). The only notable difference vs. a speaker cone is that, as its name suggests, surface transducers are attached onto a surface and vibrates it to indirectly produce sound. Among surface transducers' many advantages (like the ability to turn any common object with a flat surface into a viable sound-producing device), xctr is based on their ability to reproduce audio with superb volume and frequency response in an inexpensive and portable format.

The background information I have about surface transducers are mainly from the YouTube channel Tech Ingredients as well as Dayton Audio's specification sheet.

Surface Transducer Selection

Currently, the only suitable surface transducers I've found online are the ones from Dayton Audio (sold on Parts Express). 

Size12mm25mm
High Efficiency

Spider Feet
Low Impedance

According to Tech Ingredients, the high efficiency version produces a good frequency response as well as providing a good volume for the input power (as it is high efficiency variant)


Specifications

40 W peak, 32 W RMS transducer unit paired to 30 W amp. 

Surface transducer speakers tend to push out big volume compared to its wattage, and this is the high efficiency variant, so the max volume is not small at all.

Design

Surface transducer based loudspeakers are usually kept in their barebone appearance, just a panel connected with the transducers and hung on the wall, which is something really not desirable if I were to bring it around to use it.

Therefore, I just focused on the aesthetic appearance and usability without being too concerned about the design's acoustic effects. 

(written design)

I wanted the speaker to be made of two panels sandwiching a hollow section that contains the electronics. I was concerned about the method of attaching the panels to the speaker's body, as anything intrusive/aggressive will mess with its acoustic properties and possibly introduce resonance, as well as transferring the vibration to the floor. The more isolated and free it is, the better acoustics (I think). 

(sketch)

(blender)

(cad)

(prototype)

Results

(YouTube video)

I am personally intending to use it as an electric guitar cabinet, connected to my guitar through USB ADC interface and AmpliTube 4 software.

One of the core weaknesses of surface transducer loudspeakers is the weak reproduction of bass frequencies (sub-150 Hz). 

(frequency response table for the exciter model I'm using)

I also attached the written notes I've taken watching the two Tech Ingredient videos as well as Dayton Audio datasheets in the files section. 

design.blend

preliminary design plan

blend - 717.04 kB - 02/05/2020 at 10:19

Download

  • 1 × Surface Transducer Dayton Audio - DAEX30HESF-4 High Efficiency Steered Flux
  • 1 × Panel FORMULAR XPS (extruded polystyrene) Foam Board (1' x 1' x 1")
  • 1 × Amplifier Parts-Express Class D Stereo 2.1 (15W x 2 + 30W)
  • 1 × Power Supply LEDMO 12V 60W Power Supply (Barrel Jack)
  • 1 × Speaker Wire 16 Gauge

View all 6 components

View all 2 project logs

  • 1
    Logistics

View all instructions

Enjoy this project?

Share

Discussions

Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates