"Invisible" Speakers

Maurice Boughton sent us a link to an interesting bit about speakers that you can mount to your wall to let it resonate as a speaker. You read more. They're only like $60 so it might be worth it, although I'm curious how they sound. Oh, and as for the 6 billion of you who emailed me to wish me birthday greetings, thanks, now stop!

Comments

Don't waste your time or money on these.

[CodeShark]

[Note: in "audio speak" a driver is an individual sound source -- often a speaker cabinet will have three "drivers" which show on the front - a large (bass), medium (midrange), and small (high frequency) 'driver']

I don't claim to be an audiophile, but I've got both the math background and good enough ears to know when the math works and when it "just ain't so." This can happen in one of two ways:

1. there's no way a design can produce a high quality sound, or
2. spending more money won't dramatically improve the sound.

From this background, let me tell you that as proposed on this web-site, it's not only unlikely but damn near if not impossible to design a worthwhile sound system using these drivers. Here's why:

• Multiple transducers, are required for even moderate quality sound. With more than one of these so called "invisible speakers", there is no vibrational isolation between the low (bass note) frequencies and the high frequencies. Which means that even if wall board, plywood, etc. could accurately respond to the individual driver's frequencies, the vibrations from the low frequency drivers would muddle up the other frequencies.
• (Quoting)...speakers by design focus their energies on creating high Sound Pressure Levels within a room to provide "presence"... This might be true for stadiums, theaters, etc. (large areas) but not the typical home system. he main requirement for good sound in a home setting is the ability to tune the system to match the acoustics of the room -- thus cancelling out the effects of standing waves, absorption of sound by furnishings, etc.
• ...audio purists seek speakers with flat frequency response, non-directionality, and and efficient db-to-watt level. Wrong again. Audio purists are not THAT interested in efficiency, because most (but not all) efficient drivers have very uneven frequency response.
• Different size drivers are better for different frequencies. This means that there is
• no "one size fits all driver" that can match multiple drivers through all pitch ranges. Even the high dollar audiofile "flat" speakers usually have a cone-driven sub-woofer because the "flat" speakers can't move enough low-frequency air.
• I'd rant for a while longer but here's a more practical way to throw this idea away -- what happens if for some reason you decide to move your home theater to erk -- a different wall, or a different room?

• Note to Rob: rather than spending any $$ on these, buy yourself a 10 band stereo equalizer. It'll save you a ton of money and make any stereo speaker or system you'll ever buy better because with it and a little patience you can tune your system to the room .

I'm bloody skeptical

[Fish Man]

Having dabbled in speaker cabinet design, and designed a few PA systems, been a sound guy for bands, etc., I have a few serious reservations about how well these things would work.

The biggest ones:

1) Aren't the characteristics of the sound going to have huge dependencies on the construction of the walls, the size, stud spacing, wallboard thickness etc. If the wallboard is a little loose wouldn't it "buzz" against the studs? Would pictures vibrate? Wouldn't things like stud spacing, wallboard thickness, wood hardness (of the studs) and other factors affect the flatness of the frequency response. What about metal studs? What about lath and plaster walls vs. paneling vs. sheetrock etc. ...infinitely more construction based variables of course.

2) There are several evidences in the advertising copy of junk science and BS double-talk. For example, the site claims that this technology eliminates standing waves.

Standing waves are (almost) 100% a function of room geometry (primarily dimensions of the room vs. multiples of wavelengths, absorbancies of various surfaces in the room also come into play) and (almost) 0% a function of speaker design. This claim (and some others on the site) dump its credibility into the toilet IMHO.

Bottom line, IMHO this system is likely to not sound very good at all in the majority of installations.