WHAT IS AN EXCITER OR TACTILE TRANSDUCER?
HOW DOES AN EXCITER WORK?
WHY USE AN EXCITER?
Surface exciter technology provides a universal, cost-effective alternative to loudspeakers, allowing for sound reproduction virtually anywhere it is desired. Issues such as weather, space constraints, vandalism or visibility can be avoided or minimized with the use of a sound exciter. Additionally, exciters may be used in a host of DIY executions to easily add sound to an existing non-audio specific project or create a portable speaker system. As long as a desirable surface is available for mounting and an amplification source can be added, exciters are the go-to product for a host of applications.
WHERE TO USE AN EXCITER?
One of the most frequent questions regarding exciters involves the placement substrate and resulting sound. There is no simple answer for sound reproduction because there are a host of factors which affect how the sound exciter will react in an individual application. Because exciters perform by vibrating against the surface by which they are mounted, the surfaces themselves can and will affect the end result.
For example, mounting an exciter onto glass provides a much different sound than mounting to a sheet of foam core. The size of the surface the exciter is mounted to, the specs of the exciter itself, and the resulting motion of the surface all factor into the overall performance and sound output, therefore no one singular answer can be provided. Even though it seems like quite the grey area, the ability to leverage flexibility with installation outweighs the need for concrete specifications. This is why exciters are a popular choice in a variety of applications including:
- Home theater and multi-room audio where visibility is a concern
- Boats, bicycles, automobiles, airplanes and other modes of transportation
- Electronic gaming machines, ATMs or kiosks which utilize sound
- Retail product displays, advertising signage or multimedia exhibits
- Bathroom installations including tubs and shower enclosures
- Commercially distributed audio
- DIY projects where sound is desired as a secondary component (ex. a photo frame which doubles as a Bluetooth speaker)
- Schools and offices, specifically within conference rooms and behind white boards, etc.
- Outdoor installations where weather concerns are a factor: decks, patios, porches, fire pits, sheds, planters, barns and more
- Kitchen cabinets, bathroom cabinets, closets, furniture, walls and other locations in the home
- Portable surfaces including coolers, folding chairs and tables, lunch boxes, wagons, etc.
You can add sound to virtually any location with a mountable surface!
WHICH SURFACES WORK BEST WITH EXCITERS?
The performance of an exciter is most greatly influenced by the material of the mounting surface itself which is why a generalized frequency or impedance response curve is not provided alongside exciter specifications. Ideally, exciters should be mounted onto thin, lightweight materials which have some rigidity, yet maintain enough flexibility for the vibration to disperse sound accordingly. Below is a simple guideline for exciter usage with common surface materials.
Recommended surfaces for Exciters:
- Foam Core Board
- Plywood (1/2" or thinner)
- MDF (1/4" or thinner)
- Large panes of glass
- Drop ceiling panels
EXCITER SELECTION AND TYPES
Once a project has been identified and a mounting material has been sourced, the next step is assessing which exciter would work best in the application. There are more than 25 different varieties of Dayton Audio exciters, each with their own features and benefits. A topline overview is provided below to assist with determining which exciter will be perfect for your next project.
TYPES OF EXCITERS & ASSOCIATED SKUS
Selecting an exciter involves a number of factors including application location, surface substrate, size and weight of the mounting surface, coverage area and desired result. To assist with narrowing down which exciter to choose, we have provided simple descriptions for a few of the most common types of exciters. Please note certain exciters span across multiple categories, therefore it is best to review all benefits when selecting which exciter best meets the needs of your project.
As the name suggests, COIN TYPE exciters are smaller and typically less than 1” in size. They are perfect for applications on smaller surfaces or in compact areas where space is limited. Coin type exciters are often used in toys, monitors, small glass enclosures, etc.
Instead of moving air, BONE CONDUCTING exciters convert electrical signals into clean mechanical vibrations which stimulate the bones in the ear. The brain then interprets this stimulus as clear sound. These exciters are ideal for applications where the listener will be in contact with the surface the exciter is mounted to, such as massage tables, reclining chairs, etc.
EXTENDED MOUNT exciters are designed for projects featuring a larger mounting surface or a need for robust mounting due to power handling. Often leveraged in home projects such as doors, drop ceilings, large windows or decks, these exciters provide an extended frame or stabilizing legs for added contact between the exciter and the surface.
When increased sound performance is required, HIGH POWER exciters provide the specialized mounting provisions and assembly needed to deliver maximum output. These exciters may be secured to a wide range of materials and in multiple directions as well as attached to moving objects.
If elements are a concern, WEATHER RESISTANT exciters allow for more flexibility and installation options. Their hermatically-sealed design permits indoor or outdoor installation in a variety of conditions including extreme temperatures and water exposure.
Add the sense of touch to computer applications with HAPTIC FEEDBACK exciters. Their ultra-compact design enables incorporation into a variety of small-scale applications such as virtual reality where tactile response is desired.
The most notorious tactile transducer, BASS SHAKERS work on the principle that low frequency bass is mostly felt and not heard. When mounted to a couch or chair, BASS SHAKERS add a fourth dimension to the listening experience as they transfer electrical energy to mechanical energy. Some sound waves are simply too low to hear and therefore are felt through the body, delivering high impact response in home theater and gaming applications. The bass shakers also reinforce sound waves in the bass region that you can hear by adding the "feeling" part of the experience.
Here are answers to some common questions regarding the use and application of exciters for audio:
1) Why select an exciter over a small speaker or conventional transducer?
Exciters work by vibrating the surface they are mounted to, creating a high-quality invisible speaker. Because the substrate/surface is being vibrated to produce the sound, there is no need for grills or openings in the surface, making the system more resistant to vandalism or weather ingress. The exciter's thin profile makes it perfectly suited for applications where there are space and depth limitations. In addition, the wide-angle sound dispersion from an exciter often exceeds standard loudspeaker performance.
2) Can two exciters on a single panel create stereo sound?
Yes! It is possible to use a left channel and right channel exciter on a single panel to achieve stereo sound. The quality of the stereo image will be determined by the distance between the left and right channel exciters, and the symmetry of their placement on the panel, just like the distance between conventional loudspeakers affects their stereo image. Groups of exciters can also be used for the left and right channels, following the placement recommendations in this article.
3) How can I increase the low frequency (bass) sound being produced by the exciter?
Bass and low frequency sound are enhanced greatly when using larger panels or increased areas of substrate. Additionally, using a heavier substrate will allow deeper bass to be achieved, but at the expense of reduced treble output.
4) Will the vibrations from an exciter be visible or "shake" the device or substrate the exciter is mounted to?
Because the vibrations are small and "fast", and propagate over a larger panel area than a typical speaker, the movement of the surface is usually not visible to the listener. As an example, should the exciter be used on video displays, the visual impact of sound being generated from the panel is unseen. Also, most electronic devices will be unaffected by the vibration of an exciter.
5) How are exciters mounted or affixed to surfaces?
Most exciters incorporate a mounting ring with peel-and-stick film adhesive that is used to mount the exciter to most any substrate or surface area. Prior to mounting, surfaces should always be prepared (clean and dry) to remove dust, oils or any other elements that may impede the bonding of the adhesive and surface areas.
6) Does placement impact the sound performance of the exciter?
Placement does impact the sound being produced by the exciters, and therefore prior to selecting a permanent location listening tests and audio testing is recommended. Exciter placement is covered in detail in Exciter Installation, but in brief, exciters that are offset to the side (not centered) on a panel provide the best sound experience. However, this may not always be the case as sound quality is subjective and can be perceived differently from listener to listener.
7) Can I attach exciters to ordinary surfaces (walls, ceilings, doors)?
Yes! Exciters can turn ordinary surfaces into high-quality speakers, and exciters can often be hidden behind or inside panels to provide sound from an invisible source. Unlike in-wall speakers, which interface directly with the air and require visible grilles to protect the drivers, an exciter sets the wall surface itself into motion to produce sound, so no grille is required. The surfaces that will give the best performance are those which are thin and light, like cabinet doors in a kitchen, or a fiberglass shower enclosure.
8) How does an exciter differ from a "bass shaker" device?
Exciters differ from "bass shakers" in two important ways. Normally, a bass shaker device will have an internal mass element inside a housing, and the reaction force from vibrating the mass creates the low-frequency bass vibrations. In an exciter, the mass of the motor structure remains stationary by its own inertia, and vibrating energy is transferred directly to the surface by the voice coil. Also, the design of a bass shaker is usually limited to low frequencies because of the large mass involved, while an exciter can produce the full range of sound because the moving mass is low. Choosing an exciter with a suspension system that is more "stiff" can increase the sound efficiency of the exciter and panel, while limiting low frequencies.