Why Are Humans So Brainy?

Scientist Suzana Herculano-Houzel is a neuroscientist at the Institute of Biomedical Sciences in Rio de Janeiro. In this TED talk, she explores human brains in search of answers to puzzling questions about humanity.

Here is her talk:

Suzana developed her own way to count the number of neurons within a brain. She calls it “brain soup.” It’s a simple and fast way to analyze and compare the brains of various species.

A few highlight facts:

  • a brain’s size and the number of neurons are often not related
  • the human brain has on average 86 billion neurons
  • 16 billion of these human neurons are in the cerebral cortex
  • no other species (rodent, primate, etc.) yet studied has so many neurons in its cerebral cortex

The connections between diet and brain potential are fascinating.

Fun stuff! I think I need a sandwich :)

Quick Speaker Frequency Response Test

Home stereo speakers are typically rated in terms of frequency response. There are high-tech ways of measuring this and other ways of evaluating speakers, but this post gives you a quick way to check a loudspeaker’s frequency response at home using only your eyes and ears.

audio speaker

tweeter (left) for high frequencies; woofer (right) for lower ones

The human listening range is commonly described as ranging from 20Hz on the low end to 20,000Hz on the high end. Most human hearing happens in the middle of this range, between 1500Hz and 4500Hz, but the higher and lower ranges are important when listening to music (…or attempting to survive in the wild!)

Desirable stereo speakers have a “flat response”, meaning that low, medium, and high frequencies all have an equal volume. Cheaper speakers are able to achieve this over a small portion of 20-20,000Hz, while better speakers can achieve this over greater portions of 20-20,000Hz. Better speakers are typically more expensive due to the costs of materials, manufacturing intricacies, and brand hype.

To give your speakers a quick test, hit play on the video:

Do your speakers sound evenly from bottom to top? At what number can you start hearing the sound on the low end? Where does it stop up high? How much does the volume change while rolling through the middle range?

Try this video on several devices and you’ll quickly hear the differences from one speaker to the next. The video plays the same volume from bottom to top – it’s your speakers that create the silent points or volume spikes.

Many “good” speakers only begin to sound in the range of 40Hz on the low end and go up to at least 15,000Hz without noticeably fading. My MacBook Pro fades in on the low end around 130 Hz, whereas my larger stereo speakers start sounding around 22Hz.

For fun, here are a few frequencies to help connect these numbers to real life sounds:

  • 16Hz – The lowest note on large organs (low C on a 32′ stop)
  • 20Hz – “The lowest people can hear” (not strictly true, but this is an intro…)
  • 32Hz – The lowest note on many church organs (low C on a 16′ stop)
  • 65Hz – Very deep bass singers can sing this note
  • 82Hz – The lowest note on a trombone
  • 196Hz – The lowest note on a violin
  • 261Hz – Middle C
  • 1000Hz – Very high sopranos can sing fundamental frequencies in this range
  • 3500Hz – Fundamental frequency of the highest note on a harp
  • 8372Hz – Fundamental frequency of the highest note on an organ (high C on a 2′ stop)
  • >8372Hz – Overtones, consonants, percussion, etc.

Other Resources

Reviews and pictures of amazing speakers can be found at Stereophile.com. Most of these are visually stunning and really expensive.

For conversation and info about older speakers, no resource matches AudioKarma.org.

Introverts TED Talk


Three cheers for Susan Cain for helping the world realize that our introvert:extrovert natural tendencies aren’t reflected in today’s structures!

QE for Beginners

British humour…

(Note: this is comedy – not news!)

(… or is it the news? It isn’t far from what’s happening!)

Posted in: $$$

16 Ways to Make $100 (with semi-legitimacy)

You may not like these options, but the following techniques have been proven to put $100 in your pocket over and over again.

It would be best to make your next $100 on something legit, but for those looking to squeeze an extra few dollars out of almost nowhere…

Note: For real ideas, try  www.Make-100-Dollars.com

1) Dumpster dive for bottles

At 5 cents a pop, you only need 2000 empty beers to reach $100.

2) Theft from loved ones

Just kidding. This is a colossally stupid idea unless you like jailtime and having no friends.

3) Cash in as an independent rock musician

Find 3 pals, practice for months, record an LP, tour 25 cities, and hope to sell 45 CDs.

4) Circular math

Lend yourself $120 from your long-term savings, pay yourself back a down-payment of $20, and record the tranaction on a napkin of your choice, take another shot of JD, and be sure to discard the napkin as soon as possible.

5) Prayer

Where’s the harm in trying? :)

6) “Protection” money from neighbors

$5 a week for you to NOT beat up a neighbor x 20 neighbors = $100 per week. Recurring income potential.

7) Palladium rustling

Platinum & palladium are good for catalytic converters. Find 5 large vehicles (preferably SUVs – cars that need more pollution control carry more of the precious metal), cut out the catalytic converter, and laugh your way to $100.

8 ) Work 7.69 hours at an Alberta McDonalds

That’s right – the job market is so hot in Canada that brand new burger-flippers, fry cookers, and drive-thru window operators are making $13 an hour. Starting wage. Actually, this might be the best option from this entire list…

9) Think up a good joke

Send your joke to Readers Digest and hope for the best.

10) Piracy

Find a deserted highway or spot on the open seas, practice your accent, and watch the money happen.

11) Set up a mobile pay toilet

Dirty work, but set up shop next to a concert, ball game, or outdoor event, advertise as having “the cleanest seat in town”, and charge $5 for 5 minutes. Make $100 in less than an afternoon.

12) Buy gold

Throw $100 USD at gold, wait 30 days, then trade your gold back for USD. WIth today’s rate of currency colapse, making a spare $100 is almost guaranteed.

13) Bet against the Toronto Maple Leafs

Always a safe bet.

14) Set up an online business

How hard can it be?

15) Invest $2857.14 at 3.5% interest.

Thanks to Fedhead Ben, compound interest now almost pays for your banking transaction fees.

16) Clean out the vacuums at a local car wash

Most automotive vacuum cleaners hold several $$’s in change by the end of an average day. You’ll have to rinse off your findings, but this is some of the easiest $100 around.

Bonus #17) Search online for “$100 Prize”

There are lots of contests & competitions for a $100 prize. Who knows, you just might win something. But personally, I’d stick to something more proven to actually make $100. :)

Realistic Mach One – 4024, 4024a, 4029

Way back in the late 1970’s, Realistic produced some of the most iconic speakers in stereo history. They had their faults, but boy did these puppies rock. Their look with the grills off is hard to forget and they shake walls if connected to the right amp. Only a fool would trade today’s best speakers for these Titans of a bygone age, but many collectors have a pair in the basement hooked up to a volcano of a power amp so that once in a while they can make the house rumble like it’s 1979 all over again.

Much has changed in speaker technology over the years. Loudspeaker research in the 80s rewrote the textbook on cabinet design. Materials have shifted from wood and paper products to polymer composites. 2.1, 5.1, and newer surround audio-visual systems have largely replaced the “2 big boxes” approach to home audio. Yet, despite these changes, you can still find reasonably informed people who sincerely believe that the Mach One’s are just as good as today’s best new equipment.

This post won’t argue past vs present, but let it be known: there’s a pair of Mach Ones in the basement. :)

Realistic Mach One 4024a

Young and foolish in the 90s…

Why People Love These Speakers

Two reasons: the look and the sound.

In the age of full-spectrum stereo speaker boxes, the “15 inch” woofer brought lots of low end while two horns (mid & high range) brought a clean upper end. Two large dials allowed for adjustment of the mid & high range volume +/- 6 decibels.

Realistic Mach One Dials

The speakers sounded best with a high-powered amp running at mid or higher volume. All speakers are balanced to sound best at a given volume (for example, studio monitors vs. concert stacks) and these sound right when turned up. They sound okay at lower volumes, but are really nothing special when heard quietly. Turned up, however, they pour out a wonderful sound.

Speaker placement is important with these boxes. I’ve set up Mach Ones in several dozen rooms and they sound best in a large room with at least 15 feet of distance between the grills and the listener, preferably more. The sound also changes dramatically if they are on the floor, raised, angled, in a corner, upside down, on their sides, etc. I’ve never discovered a rule of thumb that works in every room, but when placing 4024a’s in a new room I usually start like this:

  • raised 10-15 inches off the floor
  • as much room between them and me as possible
  • close to the room’s corners, but not right in them
  • angled ~35 degrees off the back wall towards center
  • not pointing directly at the listening spot (off-axis perhaps 30 degrees, or the horns “blare” too much)
  • grills off, naturally…

I also generously EQ at or before the amp towards bass heaviness. On a multi-band EQ, everything below 50 Hz is boosted a lot. These boxes can deliver heavy bass, but not without EQ support and a high powered amp. Without EQ or if you’re using a low-powered amp, the sound from these boxes are quite disappointing.

Officially they sound down to 20 Hz, depending on your information source. While this is true, the response is nowhere near flat. With EQ support, this problem largely disappears. Unlike many newer speakers that simply do not sound below 35-40 Hz, the Mach Ones can give nearly full-spectrum sound in one box with a little signal modification.

As for the look of these speakers, people either love gratuitous woofer or they don’t. There is little middle ground. To my eyes, there is no finer looking speaker in the era.

Models Compared – 4024, 4024a, 4029

There is debate about which models were the best, but here’s the quick rundown on the three models of Mach Ones released by Realistic:

  1. 4024 – Originals, made by Tandy in 1977. Woofer has rubber surround that doesn’t rot (originals are still great in 2014). L-plate on the front uses 10 screws. Came with a lifetime warranty.
  2. 4024a – Same as the 4024, except made from 1978-81. Came with a 5-year warranty.
  3. 4029 – “Junk” according to 4024/4024a purists. Made by Optimus from 1982 to 1984. Uses different components. Woofer has a foam surround that needs replacement. L-plate on the front uses 6 screws. The “VL mods” (see “Modifications” below) only apply to this model. The resale on the 4029s is lower than 4024/4024a, and most people say that the 4029s do not sound as good as the original 4024/4024a speakers.

Basic Specifications

Impedance: 8 ohms
Response: 20-25000 Hz (no +/- db listed; sometimes “25-22000 Hz”)
Crossovers: 1200, 4500 Hz
Speakers: 15″, horn, horn
Peak: 160W
Weight: 65 lbs
Dimensions: 28-5/8″ H x 17-3/8″W x 12″ D
Original price: $400/pair (1977)

How Good Are They, Really?

I don’t listen to mine regularly, but I’ll never throw them out. How’s that for an answer?

The critics call them boomy, harsh, muddy, and generally overrated. It really depends on what they’re being compared against, what room you’re filling with sound, the amp, and the volume level. In some settings they are pure gold, while in others they’re just heavy obsolete museum pieces.

Some music where they shine includes organ music, bombastic symphonic music, and loud rock like Back in Black, Wayward Son, or the 1976 Boston album.

Compared to today’s full-spectrum high-end speakers, the Mach Ones sound slow and imbalanced. However, compared to many of today’s mid-range speakers, white van speakers, computer speakers, or speakers with bass that disappears around 40 Hz, the Mach Ones are still a good option.

Original Description

This is how Realistic described these speakers when originally released.

Realistic Mach One. The first under-$400 home speaker system with the power capacity to easily handle 100-watt musical surges and the ability to reproduce them with awesome realism. The powerful heavy-magnet 15” woofer moves such massive volumes of air you can feel the bass. The 4-cell midrange horn adds presence for that “live sound,” and its wide dispersion angle assures a good spatial image in stereo systems. The tweeter horn delivers highs so well defined they seem to hang in the air with a bell-like clarity. And a special L-C crossover network blends all speaker elements for a response free of of peaks and valleys. To prevent treble attenuation, the grill cloth is almost “acoustically transparent.” Once you’ve heard the soundtrack from a film like “Tommy” or “2001, A Space Odyssey” on the Mach One, we don’t think you’ll ever settle for a lesser speaker – especially if it costs more! 20-25,000 Hz response, 8 ohms impedance. Genuine walnut veneer finish.

Modifications / Updates

An Audiokarma.org user named “videolady201″ has developed a set of upgrades for the 4029s that are ideal for hobbyists who like tinkering. Basically, the modifications flatten the response and clean up the sound. This is accomplished by drilling inside the cabinet to give the woofer cavity additional space and by altering the crossovers. I’ve never heard a pair with these modifications, but the reviewers rave.

For an introduction to the topic, see the Audiokarma thread here.

The PDF with detailed instructions, pictures, and test results is available here and here and here.

What Are They Worth?

Ultimately, they’re worth nothing if you don’t like cool speakers or don’t want 130 lbs of vintage thunder in your house.

As of 2014 in Canada, I’ve seen many pairs of 4024/4024a’s sell through online markets in the range of $200. If they’re in lousy cosmetic condition but still work, the price drops a little, but not much. The most expensive I’ve seen for “mint condition” Mach Ones where they actually sold (it wasn’t some nut way overcharging) was around $350.

If you ever find a pair at a garage sale for under $100 and they work, grab them RUN. Even if you don’t like them (…or your partner won’t let them into the house), you can likely recover your costs if you’re patient.

Other Realistic Speakers & Vintage Gear

I’ve owned several 1970s/80s Realistic components (amps, receivers, EQs, etc.) and was never excited about any of them. It’s not that they were junk, they were just fairly average. I’ve also owned a couple other pairs of Realistic speakers (Nova’s) and was thoroughly underwhelmed.

It’s possible that I didn’t fully appreciate this gear or that I didn’t put it in a setting to shine. However, I suspect it’s more likely that the 70s-80s Realistic team got lucky with the Mach Ones.

I’ve never had the pleasure of a side-by-side featuring Mach Ones with Realistic’s later models, the Mach Two or Mach 5000 speakers, so I can’t confirm or deny the popular opinion that Realistic Mach speakers went downhill after the 4024a Mach Ones. There are mixed reviews online, but I’d endure a home test if the opportunity arose. :)

Links Around the Interwebs

To start with, this may be the greatest quote about Realistic Mach Ones ever:

Mach One Quote

The full thread is here.

For more Mach One fun online, here are some fun places to start:



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