Portable Media Players are great for listening to music on the go. At home though, using headphones may not be the most convenient or comfortable option. [decpower] didn’t have a stereo to connect his iPod to. Since he didn’t want to shell out a bunch of money to buy one, he decided to build his own iPod dock and powered speaker combo.
The case is made out of plywood: many, many layers of plywood. Each layer of plywood was cut out using a laser cutter. Unlike most speaker cabinets that have a distinct boxy enclosure, this unit is mostly solid with cutouts in each layer only where voids were designed to be. [decpower] tried to replicate the Bose Wave Radio internal sound passages. Up top a dock slot complete with a 30-pin connector makes connecting an iPod super simple.
Unfortunately, [decpower] doesn’t say what he’s using for an amplifier or where his speakers came from. He does indicate that there is an internal battery for powering the setup and it appears there is a volume knob out back. Regardless, the final project looks pretty good and [decpower] deserves some kudos for the unique construction method.
IIRC the Bose waveguide “secret” is a 4:1 ratio where the channel from the rear of the speaker is 4x the length of the channel from the front.
Someone once told me the speakers were “out of phase to each other” so reverse the Pos and Neg of one speaker would make them “Bose-like”.
I call shenanigans though
“I call shenanigans though”
Based on what?
Because out of phase speakers really do not sound good.
If you’re not exactly the same distance from both speakers the sound will be out of phase by the time it reaches your ears anyway.
Shannon, thats true for some frequecies (remember the wavelength here)
but those frequencies that are received out of phase still are out of phase in a very specific way.
The only reason why someone would enjoy listening to music like this is that all the mono information is now moved to the sides and those minispeakers suddenly sound really stereo… i don´t think that bose would do something as simple and as that.
So an entirely credible theory to how Bose get their sound then.
Maybe because the effect of cancelling certain frequencies out by putting the transducers out of phase, cannot be adequately mitigated by using this 4:1 arrangement. Then again, Bose products never seem to be designed for accurate reproduction, but rather to provide a fresh, roomy sensation.
I don’t understand why everyone is mad about Bose here. Not because I think Bose is good, but because this build has nothing to do with Bose.
Whatever “bose sound” is, there is a design called transmission line and it’s a pretty interesting and efficient design. However, there is a complicated math behind it. The idea is to get the sound from the back of the driver and “convert” it into a useful energy instead of suppressing it inside the cabinet. In order to make it useful, one need to carefully calculate the length and shape of the duct based on the driver’s properties. When done right it sounds really good.
In this build however, it doesn’t seem like the author followed any theory on how TL should be built. Also, the driver he is using (seems to be Visaton K50) is a crappy mini speaker to be used in kids toys to reproduce “meows”. With its 400Hz resonance frequency and 10K upper frequency this cabinet won’t be doing any improvements to the sound, except for adding some “echo” (an improvement?). Also that plexi in front of the speaker is baffling (pun).
All in all the build is quite solid and well executed, but I’d be really surprised if it sounds much better than internal iPhone’s speaker.
P.S. There are really cool audiophile speaker builds out there, why HaD always posts speaker projects which have very little attention to actually reproducing sound.
Why on earth would anyone try to copy the worst crap ever? Good lord people, BOSE is the damn wall-mart of speaker world. They don’t sound better, they sound a bit different because they intentionally ruin the sound to sound different. From the sound perspective those things look.. well.. very sub-par to what he could have done. Construction is pretty nice though.
That out of phase trick is as old as stereo. Eighteen eighty one, 1881 that’s right. I have read a quote of that time, something about a click heard both ways. It was in all the A/V headphones used at Purdue in the 70’s. Mono sources fake stereo. I would bring my phones into the library to listen to assignments in straight easy to focus mono for the voice.
Look at all the TV’s that had some abominable circuit to screw up the voice from dead center to a wall to wall smear. Usually set on by default.
And remember “No highs no lows, just Bose”!
I’m old school when it comes to speaker building, and believe in size and separation foremost. I’ll keep an open mind that maybe this bit of acoustic trickery is worthwhile, but I notice [decpower] made no claims as to how this sounds, good or otherwise. And lacking that, I can’t help but think that building two plain old boxes, that can be split apart for stereo separation or latched together for portability, would not only sound better but use far less material.
Why go the length of making an actual sound chamber (rather then use a cupped hand) when your just gonna cover most of the ‘output holes’ with Plexiglas? *puzzled at my own understanding of sound*
Friends don’t let friends buy BOSE…. they should also not let them build functionally equivelent either!