There is a very interesting trick that you can pull with small speakers to make the listener believe that you have this amazing ability to make loud low tones (which is physically impossible below a certain size). You synthesize the overtones of that low tone (which you can reproduce), which will fool the brain into thinking that the low tone itself is present.
Pianos have the same effect for the lowest notes, they will not reproduce the bases directly because the soundboard simply isn't large enough to accommodate the waveform. But the harmonics do fit and again your brain will interpret the harmonics pattern in such a way that they conclude the low tone is actually present.
This is called the 'missing fundamental' and is one of the more interesting psycho acoustic phenomenon.
It works like this: instead of playing A0 directly (27.5Hz) you'd play 110, 137.5, 165, 182.5, 220 etc all the way up to say 2 KHz in diminishing fashion as you go higher. For a piano you'd have to keep track of odd/even harmonics and ensure they are in the right relation to each other to get the right timbre. The brain then is apparently capable of determining the distance between those harmonics and make you believe that you are hearing A0 even though that frequency is not at all present in the output.
Has this been the trick employed by those tiny Bose speakers that got popular in the 90s?
I remember being in some kind of demo truck as a kid, where they were showing a scene of Jurassic Park (from a Laserdisc!) and they had these big speakers left and right in front and small ones behind, and were blasting the audio at pretty high volume so you would think "surely the thick base is coming from those big speakers up front". Then, half way into the demo, they would open up the "speakers" in front of the audience, revealing the surrounding wood to be fake and the actual speakers inside the fake housing being just the same tiny ones as those located in the back.
I remember being very impressed by that demo. By the speakers, but actually even more by that Laserdisc ;-)
The trick the Bose Acoustimass system uses is a form of resonance. While it is proprietary, it is fairly easy to build for yourself. In the 1980s, Popular Science (or Mechanics, I forget which) had a review of these speakers, and they told the "secret":
Take your small bass or midrange speaker (something with large excursion of the speaker diaphragm) and place it between two "tubes" that are in a 3:1 ratio. The tube on the front-side of the speaker should be the longer of the two.
So - grab a cheap 4-5" woofer and a carpet tube. Cut the tube into a 3 foot length and a 1 foot length. Put the woofer between the tubes, sealing it up well, with the front of the woofer firing down the longer tube.
That's it. It actually works well. I built one myself using junk as a kid back the late 1980s, after reading the article. What Bose did was then "fold" the tube so it could easily fit into a box. There is probably a ratio also between the volume of the tubes and the width of the driver, among other things, but the basic idea described above will work rather well. You could even do the folding trick with an actual wood enclosure if you can calculate the lengths and such thru the curves properly.
It's similar to a bass reflex or other ported style speaker, and it scales up and down rather well (see the Bose Wave radio - IIRC, it used either a 2.5" or 3.0" single driver for the bass). The downside is that it doesn't work over a wide range of bass; the bandwidth is somewhat narrow (it is possible to offset this, though, with an EQ and amplifier, to boost those lower frequencies - plus midrange speakers in the "satellites").
I saw that demo too, though it was in a store and I don't remember a JP scene being used. Bose were always shite at accurate sound reproduction, but great at making things sound good. And nothing noise-cancels like a pair of QuietComforts.
this also happened in 90's drum and bass/jungle when Ed rush started using distorted bass following along the sub bass so you could actually hear bass solo's/breakdowns on small speakers. before that you would have like a 30 minute silence if you did not have proper speakers
Another trick to make a weak boombox sound like it is a lot more powerful is to add an external soundbox. This can be achieved at zero cost by placing the boombox into any receptacle just larger than its size, a bit taller, and like 20-50 cm deeper than the boombox itself, keeping the player inside still near the opening. Wood furniture works really well for this, and floor level is preferable since it would help further bass frequencies.
That's true, this would allow you to build a compromise antenna that works reasonably well over a range of frequencies without being tuned. On a Yagi you could probably achieve that by purposefully varying the distance between the resonators a bit from ideal, correct?
A little more context for those who aren't familiar with how sound works:
Every note an instrument makes is composed of a sine wave at the fundamental frequency of the note plus a number of sine waves at integer multiples of the note, called overtones. The amplitudes of those overtones determine the timbre or sound of a particular instrument. The difference between a guitar playing A2 at 110Hz and clarinet playing A2 is in the relative loudnesses of their different overtones.
So an A2 will be composed of sine waves at 110Hz, 220Hz, 330Hz, 440Hz, 550Hz, 660Hz, 770Hz, and so on. The amplitudes diminish as the overtones go up in frequency and it eventually peters out.
Notes an octave apart are also integer multiples. An A3 is at 220Hz with overtones at 440Hz, 660Hz, 880Hz, etc. As you can see, there are a lot of overlapping overtones. So it seems like you shouldn't be able to fake a lower note by shaving off the fundamental. If you take an A2 and remove the 110Hz fundamental, you're left with 220Hz, 330Hz, 440Hz, 550Hz, 660Hz, 770Hz. That looks quite a lot like an A3.
However, our brains are smart enough to note that there are extra overtones in there that are not integer multiples of A3's fundamental 220Hz. The presence of 330Hz, 550Hz, 770Hz, etc. are enough for our brain to realize there must be a lower fundamental that we aren't hearing that leads to all of these extra overtones. Another great example of how our brains that fill in missing data by perceiving patterns in the data it receives.
This is an important technique in dance music production. On a good sound system, especially in a club, you want the bass to have a deep low fundamental that users can feel in their chest, lower than 100Hz even. But listeners are often using earbuds, in their car, or in other places with smaller speakers that can't reproduce that fundamental. So when doing sound design for the bass, you ensure the note has some overtones above that will still be preserved.
In practice, the user experience in many synthesizers goes in the other direction where they pick a fundamental that is in the reliably audible range and then add in a "sub" oscillator that makes a clean sine tone an octave below.
In my formative years, we always had something like this playing music as we played basketball. From the age of say 13-16 we would camp out in someones driveway or a park and play pickup basketball pretty much all day during the summers. Many D batteries were used in those days. Whoever had the loudest box with the most bass would get to play their box. I was friends with some kids whose dad repaired electronics, so they always had the best box. My folks weren't interested in competing with that so I had the weakest box. That all changed as we got our drivers licenses, and we proceeded to put amps and subs in our cars. That caused a whole other wave of competition. This was from 1988-1993 timeframe so by then I think the boom box era was mostly over. The boom car era was just getting cranked up though. I have that to thank for my poor hearing in crowded restaurants now. Im relatively young, and started noticing it in the past few years. I cant hear well enough to hold a conversation with lots of ambient noise. Hearing loss is completely preventable, and its much too late by the time you notice it. sucks...
We are similar. I spent alot of time on cardboard spinning around next to a boombox. As a result I have to repeatedly ask my daughter to "speak up" or "look at me" when talking so I can read her lips.
I had the Crown pictured in that article. Used it to rock Crazy Train on the bus. Then I got tired of carrying it around and it just sat in my room for the rest of high school.
I like how they all had some kind of "turbo bass" switch - like a kid carrying around a boombox would ever not want turbo bass. The worst is when you accidentally turned it off and didn't realize for hours or sometimes days.
Of course those did have a purpose. You would run in Turbo mode all the time, except when you were running bad old software like I wrote, that used timing loops assuming a 4.77 MHz clock rate.
My father used to hit Block Scor (“Blocca Scorrimento” in Italian, meaning “Scroll Lock”), disable TURBO, and then pipe DIR * . * | MORE on our shambolic 386SX-16MHz to see all the files he had in the pigsty directory he kept all his documents in, all of which horrified me.
If I can go off on a bit of a tangent. The image at the top of the article is from Spike Lee's Do The Right Thing (1989). The character is Radio Raheem and his boombox plays only Fight The Power by Public Enemy, which was made for the film. The movie is strictly about what happens when racial tensions boil over on a very hot day in Brooklyn. But really, it's about people, and how we treat one another when we're stuck in a system more powerful than ourselves. It's as relevant today as it was thirty years ago, and not just in America. It may as well be about the ongoing protests in Hong Kong. Great movie, strong recommend.
Back to the article: I owned a JVC-100 in red, just like the one pictured. I never took it out much because it seemed so fragile and my memory is that it sounded like crap compared to a hunk of plastic durable Sony that I also owned. I have no idea where either of those boomboxes got off to. Probably sold in a garage sale at some point.
> The image at the top of the article is from Spike Lee's Do The Right Thing (1989). ...
Funny you mentioned that. I've watched that movie when I was a kid and, very impressed. I wanted to watch it again but I never knew its name to start with. Yet an internet stranger just blurts it out and makes my day. Thanks stranger.
The best boom boxen on the market right now is sold by tool manufacturers. Image search Hitachi Radio or DeWalt Radio. My plumber had the DeWalt and it boomed. Ran off the same chargeable batteries as his drill, and other tools.
I seriously forgot how much fun boomboxes were. Then we had to rehab our old apartment. Our contractor had one of those DeWalt toolboxes with the boombox built-in. I've been looking for ages for one like it and still haven't found it.
Near my office, kids gather all the time and play music really loudly on small Bluetooth speakers. I don't even dare to imagine the experience if they had one of these bad boys.
Depends - loads of those Blutooth speakers have 2" bass drivers, so the best they'll ever do is sound crap. Now granted plenty of cheapie boomboxes had lots of rattly plastic around the 8" woofer, and given a bit of volume sound like they're falling apart, or there's a bag of bolts in a washing machine.
Yet there was a decent selection from the likes of Hitachi, Sony and Grundig and possibly others that were more mini hifi with handle and detachable hifi(ish) speakers you could separate properly. It's where the whole bookshelf hifi thing started as far as I can tell.
Course you may still hate the kid's music taste. :)
I found that quite interesting: After the boomboxes went away, "outdoors" music got more personal, less communal. You had your CD/MD/MP3 players and listened with headphones.
Now common/cheap BT speakers made public music listening en vogue again. Just right for me to enter my grumpy old man phase, but interesting nonetheless. (And to be honest, it beats the sheer cringe level of someone carrying around a vintage portable record player)
This also seems to make it more acceptable to listen to music/videos on your smartphones external speakers, so I'm willing to bet that having better ones will be a factor for current/future development.
Not sure everyone blaring his own music is a good thing. Doubly true in the era where lots of music has cusses and otherwise age-inappropriate content; I can't imagine people with little kids appreciate it. Besides, it's just rude for one to force his personal tastes on another. Headphones are cheap; no one likes the guy blaring tacky rap music and forcing everyone else to hear it.
The trailer’s over here, it’s a bit rough. https://youtu.be/ik6KUwB3sus I haven’t seen anything since then indicating the project’s status, and the website is now offline. Copyright on the site was 2017, and the last blog post was late 2015. So the project went off the rails somewhere, probably lack of funding, and everybody involved still having day jobs to do...
Hah. I still have a Panasonic RX-DS20, purchased around 1990. This is a late-era device, with a CD player in addition to the tape cassette, and digital tuning for radio. It uses 10 D-cell batteries, plus another four AA to store the radio station presets.
I didn't carry it around though, it was my home stereo until I was able to afford something bigger. Since it has an aux input, I've continued to use it over the years as computer speakers and such.
In Germany we frequently called them "Ghettoblaster". Only after my brother spent a year in the USA in 1990, I heard the name "Boombox" for the first time.
How were they called in the street during the 80s?
"Ghetto blaster" has unpleasant racial connotations. It's the kind of term you'd expect your white boomer parents to throw around, as they shake their heads in looming fear that their neighborhood might degentrify. "Boom box" is considered more racially neutral so you will hear it more in the USA.
I totally disagree. I just cannot see a racial aspect in the word "Ghetto blaster". What makes you think so? Was it only used by white old men? Or by middle aged cyan women?
Using the term "ghetto" for predominantly-black neighborhoods is... one of those things black people can do that white people can't. This is less of a problem in other anglospheric countries, which don't have the history of oppression of and discrimination against black people, including segregation into specific neighborhoods and "white flight", that the United States has -- so words like "ghetto blaster" have less bite abroad than they do here.
We always called them ghettoblasters in the UK too, though the small ones, and mono speaker+radio+tape like the photos of mono sets in the article, were always just "the radio" or "the tape". Ghetto blaster was for the big stereo ones. Always stereo.
Boombox was a name that came from US TV and film, and only started to be the name retrospectively looking back. I don't remember anyone here actually using boombox back then.
We used the term in the US as well, boombox was just more common and TV English. A good deal of kids called them ghettoblasters. Less commonly used but heard from time to time was JamBox and BumpBox. IIRC GhettoBlaster seemed to be used in the early 80's more where BoomBox and the others seemed to be used in the very late 80's and 90's but my memory could be wrong. I do remember when I was younger them being almost exclusively referred to as GhettoBlasters.
A friend had a Sharp ghettoblaster ('boombox'? no one called them that) with built-in vertical record player. Now that was pretty cool. I'd also nominate the Phillips Roller as an iconic stereo design - popping up here and there now in the background of photoshoots, and becoming collectable.
Unless you are on a beach with a bunch of your friends, walking around a busy city with one of these just illustrates how self-centered that person is that they think their music is the best music and everybody should listen to it. In reality most don't even care, and at worse you are just making a bunch of needless noise. It's just a failure of thinking about other people and thinking that maybe your taste is not everyone else's taste.
Well, people want slimmer and smaller products. There is more room for creativity in a large, bulky form factor than in a small enclosure sized to barely fit the components. Boom boxes were very heavy and bulky; today's consumers want svelte designs that fit easily in one's pocket.
I walked through a store recently that sells modern "boom boxes" and bookcase stereos, and it seems like today's trend is tacky and over-the-top like a chromed spaceship with RBG LEDs.
I remember in the early 80's the transition from all-analog to LCD display boxes, which allowed more precise FM tuning, and programming for copying tapes or an alarm clock.
And that the #1 item in terms of interest and sales volume at a lot of consumer electronics retailers was the boombox.
Their size really did get ridiculous - carrying one around was a workout.
Nowadays you can be fairly certain that just about every set of somethings will be ‘collected’ by a set of aficionados whose number of members is or exceeds two.
I had a red JVC PC-30 single deck that took something like 8 D-cell batteries... it had touchy volume controls that needed cleaning all the time because any dust or oxidation would sound like white noise mixed with nails on a chalkboard when changing the volume. It was kinda cool because the speakers detached. I often plugged in a $300 Sony Discman with crazy skip buffering and anti-skip tech (D-828K).
I was lucky.. there was a Tower Records 1/2 mile (1 km) from my house, the one where Metallica played that concert in the parking lot. And somehow I acquired a 1990 West German The Doors - The Doors CD.
Pianos have the same effect for the lowest notes, they will not reproduce the bases directly because the soundboard simply isn't large enough to accommodate the waveform. But the harmonics do fit and again your brain will interpret the harmonics pattern in such a way that they conclude the low tone is actually present.
This is called the 'missing fundamental' and is one of the more interesting psycho acoustic phenomenon.
It works like this: instead of playing A0 directly (27.5Hz) you'd play 110, 137.5, 165, 182.5, 220 etc all the way up to say 2 KHz in diminishing fashion as you go higher. For a piano you'd have to keep track of odd/even harmonics and ensure they are in the right relation to each other to get the right timbre. The brain then is apparently capable of determining the distance between those harmonics and make you believe that you are hearing A0 even though that frequency is not at all present in the output.