I remember the first time I took apart an old DVD player. I was surprised at all the empty space inside. Same deal with an old CD player. Of course, both of these now have versions that aren’t much bigger than the disc itself. And now here is the inside of a Blu-Ray player. Wanna bet that in two or three years time, it’ll be half that size or less?
I understand that some space is saved when newer chips come out that incorporate more features into a smaller physical footprint, but it seems like the bulk of the space savings is always there for the taking and that older models just don’t take advantage.
Empty space can also help a lot with heat dissipation; a lot of electronics packed tightly together can generate a lot of warmth (as anyone who owns a laptop can tell you.)
The engineer(s) designing the internals need to know how much room is inside the case.
The engineer(s) designing the case need to know how much room is required for the internals.
Neither can do thier work until the other is finished.
In order that they both can start as soon as possible, The “internal” team makes a wild ass guess at how much space they really need, then multiply by at least two “just in case” and that is what the case engineers allow for.
Once the first generation is done, there are far fewer unknowns, and space can be optomized.
a) Because the case has to be a box, so it needs to be as tall as the tallest component. In the Blu-Ray player, it’s probably the disc assembly that determines the height. I’ve taken apart my Tivo, and it’s height is mainly due to the hard drives.
b) People expect a $300 piece of electronics to be chunky. They’ll accept that a $50 one is not.
c) Early expensive versions of things tend to have much fancier front panel displays and controls that require bigger panels.
I would guess that the astronomical leaps we’ve seen in microprocessor technology would also account for our ability to miniaturize products over time.
Also a lot of early CD players were designed to be the same width and depth as other hi-fi separates, so they would fit in stacking systems (remember those?). As most stacking systems at the time included record players (remember those?), this standard size was pretty large.
The first versions of new technology is usually cobbled together from many individual components. Once the tech is more mature, some or all of the individual components can be combined into one package.
This is even more noticable if you see the “breadboarded”, experimental version of a new device. Since connections are tentative until the product works well, it has to be easily modified. You can easily move a wire, but not as easily move a tiny line on a microscopic etching. Get it to work first, get it small second.
An early version may have multiple circuit boards with a bunch of chips each processing its piece of the task. When all of that gets worked out then it is time to refine. Get higher capacity chips and program them to handle more of the tasks within a single chip.
The early Beta Max and the early cell phones are good examples. The big boxes were full of chips all wired together on boards. Now they can design a chip to do the work that 25 or more used to do. That creates a lot of space that can be done away with.
Those are quaint, but even quainter were the 90s era virtual ones. The audio players in Windows used to have a visual representation of a stacked hifi. Quite cool, looking back on it.
20 years ago, my first CD player was fairly well filled with parts. The two main things that dictated the height were the transformer in the power supply, and the front panel display.
The depth was goverened by the disc transport - the gear-driven sled that fully opens the drawer had to be able to fully retract into the case, so the case had to be at least 11 inches deep.
Now, manufacturers are using smaller “switching” power supplies that don’t have bulky transformers, and as with your Blu-Ray inside photo, the optical disc mechanism is smaller. Some of the really small and cheap DVD players are using laptop drives.
Also, never overlook inertia. 20 years ago, CD players were being built to fit in with the other home electronics of that era - turntables, cassette decks and amplifiers, all of which were usually 15 to 17 inches wide and about a foot deep. If the CD player was introduced to the world in a six inch wide box, it probably would have had much slower adoption as people would be unable to easily add it to their stack of components.
Vertical space may be due to the design of the front panel, as well as stacked components. However, another issue is that routing a big PC board with a certain number of components is simpler than routing a smaller board, and is thus faster. I also expect that making what we called white wire changes is easier also. When you’re debugging, it is much faster to make a fix with a wire than changing and rerouting the entire board. Big boards also allow you to add test points, good for manufacturing test and probing for debug.
I’ve always though it was just marketing (mentioned above). I bought a somewhat advanced DVD player a few years ago, long after DVDs emerged on the scene. All the choices were the standard “entertainment center” size, including the one I purchased, which I recently opened up to find the expected cavernous space. (Way more roomier than even the new Blue-ray player in the OP.)
