2014 RPM Challenge: Accepted!

Today is the first day the 2014 RPM Challenge, which is the National Novel Writing Month of music!  The goal of the RPM challenge is to compose and record an entire album during the month of February! I accepted the challenge by dusting off my Cacophonator and Mohogonator, and got to work making music after dinner today. As today also marks the 50th anniversary of the Beatles invasion, this project drew inspiration from the Beatles’ back catalog!


I used the dynamic duo of Cacophonator and Mohogonator with Auditionator (i.e. Adobe Audition) to record a session for about 12 minutes at a blazing fast 192kHz sample rate.  After chopping the recording into individual tracks, I digitally slowed them down to the customary rate of 44.1kHz, thereby expanding the work to its final ~45 minute length.  For inspiration while I was recording, I listened to Beatles songs sped up to 435% (which is 192/44.1) of their customary speed.  My tracks needed a bit of post-processing: on some of them I chose to bump the pitch back up an octave or two and add “Beatle Fades” to the beginning and end.  Anyway, within twenty minutes after the recording was made, I had edited the songs and uploaded them.  You’ve read that correctly, in less time than it takes to listen to the pieces, they were composed, recorded, processed, mastered, named and uploaded.

Today is also the 50th anniversary of the first Beatles song hitting #1 on the US pop charts: “I Wanna Hold Your Hand.” This whole project was inspired by this apparent coincidence in timing, and each track was directly inspired by listening to the sped-up Beatles original.  I hope you enjoy each of the 11 tracks I created!

While My Cacophonator Gently Weeps
Got To Get You Into My Cacophonator
All You Need Is Cacophony
With A Little Help From My Cacophonator
Sgt. Cacophonator’s Lonely Hearts Club Band
Cacophonator Came In Through The Bathroom Window
Lucy In The Cacophonator With Diamonds
Got To Get Cacophonator Into My Life
A Hard Day’s Cacophonation
You’ve Got To Hide Your Cacophonator Away
Cacophonator Wants to Hold Your Hand

It may be more convenient to listen to the entire album: “Cacophonator 2: Electric Boogaloo; A Love Tragedy in 11 Parts” on the RPM Challenge site’s Cacophonator page. Just scroll down to “My Player.”  There is plenty of February left: I encourage everyone to participate!

The Milwaukee Makerspace Theater


Around 25 members have hopped in the new Milwaukee Makerspace Theater after the last two Tuesday meetings.  Its up and running in a “no hearing protection required” way!  The bass still goes way down to subsonic tones, but its being powered by a small & sensible surround sound amp.   Its a very immersive audio experience, and likely sounds much better than any 5.1 system you’ve heard because there’s only one seat!  The sound has been optimized for the single theater-goer: You!  The theater is hooked up to a DVD player, and is available 24/7  for any member to watch a movie in: no check-out required.   Note that any video source you have can be hooked up via the HDMI cable.  Alternately, you can follow the lead of JasonH, who used the theater with a portable audio player to rock out while he worked on his own project near by. See the photos below for the simple instructions on how you can start up the theater, and feel free to take a break from making by using the theater!


Home Theater with Insane Subwoofer

After the mediocre commercial successes of some of my previous audio products, I decided to pursue a project that has absolutely no commercial potential.  Although my Automated Gmail Assistant had a 0.1% view to purchase rate, they definitely delighted their new owners!   On the other hand, my novel audio surround sound processor, audio-visual processor and audiophile headphones did not produce any revenue, despite being manufactured in an exclusive edition of one each.  Not to be discouraged, the goal of this project was to expand on the core idea behind the aforementioned audiophile headphones, but to overcome the main two drawbacks of using headphones:  1) Many people find that headphones are too uncomfortable and impractical for long term listening. And 2) most headphones lack the concert-like visceral bass impact, which is that feeling of the kick drum shaking your chest that only rock and roll shows could provide.


Simply put, the Humorously Maniacal Milwaukee Makerspace Multimedia Machine (HMMMMMM) is a personal sized movie theater, with 5.16 surround sound.  That’s right, this theater is like a conventional 5.1 home theater, but with 15 extra subwoofers to delight the senses. While the bass in a live concert can be felt in your chest, the bass in the HMMMMMM can be felt in your soul(!).  In addition altering listener’s consciousness, the HMMMMMM will soon be used to screen our yet-to-be-filmed Milwaukee Makerspace orientation video as an integral part of our onboarding process for all new members. The HMMMMMM measures about 7 feet long and about 4 feet wide.  An eager movie-goer can simply climb up the integral stairs (shown on the left) and jump in through the 27” diameter escape hatch in the top of the HMMMMMM. Despite its crazy appearance, the HMMMMMM offers a surprisingly comfortable reclining position, much like that of a lazy-boy.  Check out this photo of the HMMMMMM under construction for a better idea of the ergonomic internal layout: There is a pillow for one’s head, and ones feet extend to the right.  The 27” display is mounted to the angled portion on the top surface, about 24” from the viewer.  Eventually, two 24″ monitors will expand the visual experience into the periphery.


The audio portion of the HMMMMMM is a 5.16 system.  The high frequencies are played by 5 uninteresting Swan/HiVi speakers that are arranged in a properly boring 5 channel surround configuration.  The more exciting portion of the audio system is the subwoofer – well, the 16 (Sixteen) 10″ high efficiency subwoofers that provide that TrueBass™ sensation the masses crave.  Its clear from the use of 16 subwoofers that one object of the HMMMMMM was to create an audio system that plays low bass.  Playback of really low bass typically requires an extremely large speaker box, and still notes as low as 20 Hz are rarely audible.  However, inside any speaker box the bass response is naturally flat to much lower (subsonic) pitches.  For more on the sound pressure level inside and outside speaker boxes, check out this link.  The graph below is a measurement of the SPL or sound pressure level (how loud it is) versus frequency (pitch) at the listener’s ears in the HMMMMMM.


The graph shows that with a sine wave input, the SPL inside the HMMMMMM is 148.6dB at 40 Hz.  That means the acoustic pressure on the 27” diameter escape hatch is 45 pounds.  Excellent.  Note that earplugs in addition to earmuff style hearing protectors are mandatory to safely experience the TrueBass™.   To understand this strict hearing protection requirement, lets compare the sound pressure level inside the HMMMMMM to other audio systems that may be more familiar.  Note that the loudness of these other audio systems are not visible in the graph above, because essentially all other audio systems (including yours) are inferior.  Adjusting the margins of the graph a bit produces the following graph:

SPL_of_many_systemsThe plot shows how loud typical audio systems are, and how low they play.  For example, cellphone speakers play only a bit below 1khz, and are ~90 dB if they’re 40cm from you.  When a Jambox-type bluetooth speaker is about 60cm from you, it plays ~10 dB louder, and another 1.5 octaves lower, to 200 Hz.  Typical bookshelf speakers can get another 5 dB louder if you’re 1.5 meters from them, but only play down another octave to 100 Hz.  OEM installed car stereos are a big improvement, but they’re still not in the same league as the HMMMMMM.  Yes, the IASCA record holding car is louder than this, but it plays only from 50 Hz to 60 Hz, which isn’t even really bass.

Note that the difference in loudness between a cellphone and a car is 20 dB, while the HMMMMMM is 30 dB louder than a high-performing car stereo.  Also note that the frequency range of a piano, with its 88 keys, is about the same as a bookshelf speaker – a bit over 7 octaves.  Surprisingly, the subwoofer portion of the HMMMMMM has a 6 octave bandwidth, but it plays the 6 octaves you’ve never heard before!  The HMMMMMM plays 6 octaves below what your bookshelf speaker or Jambox calls bass. The HMMMMMM has a +/- 6 dB passband extending down to 2 Hz, with the output at 1 Hz being nearly still above the 120 dB “threshold of pain.”

Disclaimers: For safety, the big 2000 Watt amplifier that drives the HMMMMMM to its full potential is not available when the author is not present.  Ironically, the author has taught 75-100 people, the eager early HMMMMMM listeners, how to properly insert earplugs, meaning that the HMMMMMM is actually a learning tool for hearing safety! Finally, the author has some hesitancy in having the HMMMMMM reproduce recordings with 5 Hz content at 140 dB, because typical hearing protection has little effect at these unnaturally low frequencies.

PS:  Please don’t hesitate to contact me if you’d like to help with the video scripting, filming or editing.

Snow-Globe Video

Just a minor update here from my recent Snow-Globe blog entry ( http://milwaukeemakerspace.org/2012/12/custom-snow-globe/ )

I made two VIDEOS about the snow-globe. The first is just a brief video showing the finished project. The second video is a longer “How-To” which includes some video, but is mostly a photo slide-show of all the steps I took to create the project.

For an in-depth step-by-step of how I built the project, check out the info I posted on Instructables. http://www.instructables.com/id/Custom-Singing-Snow-Globe/


Custom Snow Globe


Well, I’ve been slaving away on creating a unique X-mas gift for my wife and two-year old daughter, and I think I got it right. They loved it!

I’m talking about a Custom Snow Globe!

A while back, I was working in the driveway on a styrofoam project. Of course, that white stryrofoam dust gets static-charged and STICKS TO EVERYTHING. I also found that the best tool for cutting it was my wife’s kitchen electric carving knife. When I headed inside to take a break and warm up, I was COVERED with styrofoam. My two-year-old girl looked up at me and squeeled “Daddy a Snowman!”.

Indeed I was. I imagined myself inside a snow-globe with styrofoam swirling around me like a snowstorm. But could I actually BUILD a snowglobe that would match my imagination?

I started looking at every snow globe I could find and set to work building one. I looked around and found a glass dome, used for light fixtures. I got two of them, and gave one to my brother-in-law, who is a clay artist, among other things, and commissioned him to make a caricature of me. Since he had one globe, and I had the other, he could make a figure that would fit inside the globe, and I could do the woodworking on the base, and insure that the globe fit that.

I headed to the local cabinet shop and talked to old high-school class-mate Steve about what wood to use for a base. He gave me a maple block, and I grabbed some scrap maple from the bin to practice cuts and routering on. At my Dad’s back-of-the-garage shop, I experimented with routing, until I could get it right, and routed a circle for the base of the glass globe, cut the wood base to length and cut a 45-degree bevel on the top edge, and routed a pocket in the bottom for the electronics.

I wanted to make a “singing” snow-globe, so I bought a singing greeting card at the Hallmark store, and then dissected it for parts. The electronics were then mounted on the bottom of the  wood base, along with a custom switch.

I headed to the Milwaukee Makerspace to use the laser-cutter.

Using the vector graphics program on the laser’s computer, I laid out an inscription for both the top and bottom of the snow globe base. I practiced on a piece of paper, and then when I actually focused the laser properly and had everything else figured out, I wood-burned the maple block, front and back.

I also used a solder station to add the momentary on switch to the greeting card electronics, so that the song would play whenever the globe was picked up to shake up the snow.

Next, was clear-coating the figure and the wood base. I used “Parks Super-Glaze”, a two-part epoxy clear coat used for bars, to completely seal and waterproof both the figure and the base, as well as to permanently attach the figure to the base.

Then, it was a matter to holding the globe upside down, filling it with water, filling the routed circular grove of the base with silicon glue, and flipping the figure and base, upside-down, into the dome of water. Once it was cured, the snow-globe can be flipped right-side-up, gift-wrapped, and put under the tree!

I’m glad to say that the project turned out just great! It was a bit of a stretch to my skill-set, so THANK YOU to the people who gave me a hand with it. Nothing quite like a project that runs the gamut from sculpture to wood-working, electronics, glass, water, laser-engraving, and more! But that’s how we grow… by stretching a little bit more every time!

Merry X-mas

From Ben the Snowman.

Arduino-Powered Surround Sound Synthesizer

The Makerspace Eight Speaker Super Surround Sound System(MESSSSS) has been supplying music to the Makerspace for quite a while now, but I identified a problem even before the system was fully installed.  Stereo recordings played back on two speakers are great if you’re in the “sweet spot.” If not, traditional approaches to 5.1 audio improve things, but all rely on there being a single “front of the room.” Unfortunately, it’s not clear which side of the 3000 square foot Makerspace shop is the front, and with four pairs of speakers in the room, even stereo imaging is difficult.

Fortunately, I’ve just completed the Makerspace Eight Speaker Super Surround Sound System’s Enveloping Surround Sound Synthesizer (MESSSSSESSS).  The MESSSSSESSS takes stereo recordings and distributes sound to the eight speakers in an entirely fair and user configurable way, thereby eliminating the need for a “front of the room.” Now listeners can be arbitrary distributed throughout a room, and can even be oriented in random directions, while still receiving an enveloping surround sound experience!

The MESSSSSESSS user interface is somewhat simpler than most surround sound processers, as it consists of only four switches and one knob.  Somewhat inspired by StrobeTV, the simplest mode references questionable quadraphonic recordings, in that the music travels sequentially from speaker to speaker, chasing around the room either clockwise or counterclockwise at a rate selected by the knob. With the flip of a switch, sound emanates from the eight speakers in a random order. Things get considerably less deterministic after flipping the Chaos Switch, adjusting the Chaos Knob, and entering Turbo Mode:  Its best to visit Milwaukee Makerspace to experience the madness for yourself.  I’m legally obligated to recommend first time listeners be seated for the experience.

The MESSSSSESSS is powered entirely by an Arduino Uno’s ATmega328 that was programmed with an Arduino and then plugged into a socket in a small, custom board that I designed and etched at the Makerspace.  The ATmega328 outputs can energize relays that either do or don’t pass the audio signal to the four stereo output jacks.  Care was taken to use diodes to clamp any voltage spikes that may be created as the relays switch, thus preventing damage to the ATmega328 outputs.

As shown by the minimal part count above, using the ATmega328 “off the Arduino” is quite easy:  Just connect pins 1 (The square one), 7 and 20 to 5 volts, and connect pins 8 and 22 to ground.  Then, add a 22uF cap and small bypass cap between power and ground, and a ceramic resonator to pins 19 and 20.  You can even use an old cellphone charger as the power supply.  Boom.  That’s it.  The real benefits of making your own boards are having a well integrated system, and cost, as the Atmel chip is $4.50 while a whole Arduino is $30.  Also visible in the photo are a programming header and the two ribbon cables that route all the signals to and from the board.

Cacophonator Enters The RPM Challenge!

At Noon today, the Cacophonator decided to enter the RPM Challenge!  This challenge is simple: Compose and record an album entirely during the month of Februrary, be that 10 individual songs or a single 35+ minute track of original material!  After a thirteen second test, Cacophonator was proven to not be up to this challenge as a solo act – It’s just too loud.  Enter Mohoganator: The distortion reducing, level adjusting perfect partner for this challenge.

The Dynamic Duo of Cacophonator and Mohoganator teamed up with Auditionator (I.E. Adobe Audition) to record a session for 10 minutes and 32 seconds at a blazing fast 192kHz sample rate.  This recording was then slowed down to the customary rate of 44.1kHz, thereby expanding the work to its final 45.5 minute length.  Within twenty minutes after the recording was made, Cacophonator had a profile set up on the RPM Challenge site and the piece normalized, saved as a low bit rate mp3 and uploaded.  You’ve read that correctly, in less time than it takes to listen to this piece, it was composed, recorded, processed, mastered and uploaded.  Talk about Non-Causal Audio Delight!  Check out the piece here, by scrolling down to “my player.” This all happened very fast, but Cacophonator still isn’t quite finished – it hasn’t yet mailed a CD to RPM HQ, 10 Vaughan Mall, Suite 201 Portsmouth, NH 03801.  Interested participants still have over 11 days to enter the challenge!

Audiophile Headphones

Sick of thin bass when listening to your favorite music over headphones? Missing that cinematic surround sound experience when you are on the go? Craving the visceral bass impact of live concerts? Trying to get to 11, but your headphones are stalled out at 6.283?  Move over anemic earbuds, there’s a new product in town: BIGheadphones: Bass Impact Gear’s new headphone product, available in two versions: Premium 5.1 (shown below in a user trial) and Mega Premium 7.2 (coming soon).

Reviewers are raging about the unprecedented dynamics, midrange clarity, and sound stage:

“Perhaps it was in the region of articulation and musical dynamics that this system impressed the most.  The dynamic bloom from soft to extremely loud was exquisite, and so clearly delineated that listeners could unravel musical phrases down into the concert hall’s noise floor and below.” The Audio Critic

“BIGheadphones speak with an organic integrity. They are hewn from the living woodendangered old growth Amazonian timber… I wept openly when forced to return the demo model.”– Stereophile

“BIGheadphones make critical listening a joy rather than a strain.  I was flabbergasted by their brilliant pitch certainty.  The midrange sounds were open, clear, and stunningly present. Playback performance like this makes use of the word transparent not only forgivable, but mandatory.” Audiophilia

“The 5.1 has an innate flair for speed and control that is incomparable. The command of bass dynamics moves beyond effortlessness to nonchalance. My eyeballs were vibrating! My hands are still shaking as I write this review.”Sound and Vision

“…the most important innovation in audio reproduction since the permanent magnet.”  –Acta Acustica

“W.O.W.”Bose listening panel

Reviewers agree that BIGheadphones are a huge leap in audio reproduction technology, larger than vacuum tubes, Stroh violins, carbon microphones and Edison cylinders combined.

Relative to planar speakers, typical box speakers are unable to develop the proper surface loudness or intensity typical of large instruments such as the piano.  This audio feat poses no challenge for BIGheadphones. Computationally modeled and optimized by a small and highly trained team of expert acoustical engineers over a period of 13 years, BIGheadphones were inspired by ingeniously thinking “inside the box,” not outside the box.  At the obsolete exterior listening position, a typical loudspeaker rarely generates even a realistic classical music concert level, but inside that same speaker, the sound pressure levels can quite easily exceed the 115 dB of a stadium rock concert. This realization was the BIG breakthrough, but was only the beginning of the struggle pursued by our elite acoustical research team.  Our uberengineers had to break the chains of common design practice to breathe the refreshing mountain air of inside-the-box acoustics, where nearly everything is inverted.

To illustrate, achieving loud bass external to a speaker typically requires the box be a very large size.  However, inside the box, the bass response is naturally flat to the lowest frequencies, and the smaller the box the louder and more impactful it becomes. Further, our astute engineers shrewdly realized that the stop-band and pass-band inside and outside the box are also opposite, as illustrated in the enlightening plot below of the subwoofer section of BIGheadphones. The Blue curve shows the hyposonic level inside, extending well below 10 infrasonic Hz, while the Red curve shows the meager sound pressure level in the more traditional listening position two meters in front of them.  Notice how the passband outside the box begins at 2kHz, whereas the passband inside the box ends at 2 kHz.  How many other speaker systems can boast of a subwoofer response that is flat over more than three orders of magnitude?  Now that’s innovation!  And this is just the customer-average response—the bigger your head the broader the bandwidth that you can brag about to your audiophile friends.

The observant reader has already noticed that this plot shows BIGheadphone’s output level is a mere 142 dB – only 22 dB above the threshold of pain.  Note though that this is with a paltry 1 Watt input – in reality, they are capable of 17 dB higher output with the optional high output amplifier add-on kit, though this reduces the playback time to under 36 hours per charge.  And that’s just the subwoofer!  The industry-leading, consciousness-altering bass response shown above is augmented by five horn loaded, carbon fiber reinforced porcelain dome, 2” diameter neodymium tweeters with single crystal silver edge wound voice coils.  With this critical addition, the frequency response of the BIGheadphones extends from below 10 Hz to 31 kHz and beyond!  Get your BIGheadphone audition today at your local Hi-Fi retailer!  “BIGheadphones, the last audible note in audio reproduction!”

(Not available in France.)

Thanks to the editors at RSW, Inc.

Redwood Audio Amplifier

A few months ago I started collaborating with Jordan Waraksa on a project that is currently on display at the Haggerty Museum of Art, in a show running until the end of December.  He sculpted a pair of wooden acoustic horns called Bellaphone 5 & 6 out of walnut.  Each horn rests on a redwood base that houses a small speaker.  If you visit the Haggerty, you’ll hear the speakers playing songs by Jordan’s band, The Vitrolum Republic.  If you really love the Bellaphones and amplifier, know they are for sale.

I developed and built the electronics for the horn’s amplifier, whose chassis Jordan also sculpted from redwood.  Because the chassis is wood and has no vents (for aesthetics), electrical efficiency became a high priority in order to prevent overheating.  I chose to use a Maxim 98400A class D amplifier driven by a high efficiency switching 15V DC power supply.  I added a digital signal processing chip from Analog Devices to increase the bandwidth of the horn and smooth out its frequency response (i.e. to improve the audio fidelity).  Analog’s ADAU1701 is a remarkably powerful chip – it is more than capable of these tasks.  In addition, the 1701 prevents bass notes (frequencies below 100 Hz) from reaching the small speakers (which are incapable of reproducing these low notes), which would otherwise emanate from the horns as distortion.  Finally, the 1701 also adds a small amount of compression, which prevents distortion at the loudest output levels.   The 1701 is actually real-time programmable via a USB connection to a computer running Analog Device’s free SigmaStudio software.  It’s a tremendously user friendly GUI environment with drag and drop audio processing blocks.

Check out the inside of the amplifier as it was being assembled, prior to the addition of many ferrite beads which eliminate the audible noise from the three high efficiency switching power supplies:  One powering the amp, one powering the DSP board, and one continuously charging a Motorola Cliq XT handset playing songs from the Vitrolum Republic.

Here are two more close ups, one of the amplifier:

And one of Bellaphone five and six:


I’ve recently made several audio synthesizer / noise generating boxes.  The most recent is the Cacophonator, whose circuit description and board layout are easy to find on the web.  Thanks to Adam for showing me how to etch my own circuit boards – something I can now do quite easily at the Makerspace.  I modified the board layout, drawn in DipTrace, so I could add SIP sockets and pin headers to tidy up the inside of the project box.  The sockets also allow the board to be easily removed, despite the 20 wires running between the board and other components inside the project box.  The  photos below were taken before I modified the circuit by adding a momentary power switch to slowly recharge the giant power supply capacitor if held for a few seconds.  I also added a LM317 adjustable voltage regulator so the power supply voltage can be reduced all the way down to 1 V DC and below.  The sonic complexity of this circuit is surprising considering its small part count, and lowering the power supply voltage further adds to the chaotic behavior of the cacophonator.  Careful inspection of the board will show additional components not associated with the original cacophonator, but are discussed on electro-music.com.  These are used for inputting audio signals (music, for example), which come out the RCA jack quite cacophonated.