Soundscience Rockus 3D | 2.1 speaker system

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As soon as I discovered that this satellite driver is a single paper 2.75" cone, I became interested in a very personal way. I've been fascinated by music and sound all my life, and messed around with audio gear since preteen years when Father brought home a then-high end Sony 7" reel-to-reel stereo tape recorder from a business trip to Hong Kong and passed it on to me the next day... realizing he didn't have the dexterity to thread the damn tape. That got me started. I've collected umpteen pieces of gear, thousands of albums, worked in a handful of audio stores, including some very high end ones. Finally, designing, buidling and fine-tuning speakers has been a hobby for the better part of three decades.

In the vast majority of speaker systems, a midrange driver is not asked to extend up to the last octave of audibility, and for good reason. A drive that can handle the all important midband where the bulk of musical fundamentals lies is usually too big to have good dispersion, with too much mass for smooth extension. That is why tweeters were developed in the first place: Small diameter for better dispersion of the short frequencies up there, very low mass for quickness and linearity. However, there has always been a faction in the audio community pursuing the holy grail of a single full range driver that does the entire audible range without crossovers. Some of these devices, just the raw drivers, cost upwards of $1000 each. Fostex, Seas, Lowther, Jordan — these are some of the names that command awe among full range speaker enthusiasts. Am I one? Well, no, I have not been convinced, but then perhaps I just haven't heard the right driver in the right design, yet.

In any case, the driver in the Rockus satellite had to be examined. A close look at the satellite showed only four hex-head bolts or screws on the back side. Time to dig through the Allen wrenches. It did not take long to remove them. There is a gasket with glue used as a seal around the rim.

Rockus satellite back panel + stand removed.

A close look into the cylinder showed thin foam damping glued to the aluminum wall, the back of the driver magnet, and four philips head screws. Careful not to let the magnet pull the long screw driver where it might damage something, I removed those screws. They turned out to hold down the flared rim in front, along with the hex-pattern cover over the front of the driver cone.

Driver cone revealed: An ordinary surround, paper cone.

Removal of the screws holding down the speaker driver had to be done with a lot of care to ensure the screw driver did not puncture the cone. When it was done, the driver could be examined in its entirety. Leads from the input terminal are soldered, not just clipped, to the driver terminals.

It's a pretty big magnet for the size of speaker. The suspension feels nice and supple, but it's difficult to see any mechanical reason for the top octave peak. I am almost positive that the boost is accomplished electronically within the electronic crossover/amp section of the system.

A close examination of the baffle/cover made me shake my head. Surely something with less impedance could have been used. This is in stark contrast to the AudioEngine A2, which dispenses with any grills over the drivers, and uses rounded, smooth contours around the edges of the openings for the driver to keep diffraction to a minimum.

This is the cover for the cone. It protects the cone, for sure, but cannot help the sound, which is guaranteed to be diffracted right at the source.

For the past week, I've been using the Rockus satellites at my desk with the grills removed. Do they sound better? I think so... smoother, cleaner, with less "venetian blind" effect when I move my head. You can see this in the on/off axis frequency response curves below.

Compared to the response with the grill on below, the lines for both on and off axis without the grill are smoother. They are also more similar to each other, 1~10 kHz.

Click for large view
Frequency response graph of the Rockus 3D | 2.1 - click for larger view.

So there you have it. My warranty-busting "upgrade". Should you wish to try it, I take NO responsibility for the results of your actions.

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