Sight And Sound Combine In This Engaging Synthesizer Sculpture

October 23, 2022 by Dan Maloney 2 Comments

We’ll always have a soft spot for circuit sculpture projects; anything with components supported on nice tidy rows of brass wires always captures our imagination. But add to that a little bit of light and a lot of sound, and you get something like this hybrid synthesizer sculpture that really commands attention.

[Eirik Brandal] calls his creation “corwin point,” and describes it as “a generative dual voice analog synthesizer.” It’s built with a wide-open architecture that invites exploration and serves to pull the eyes — and ears — into the piece. The lowest level of the sculpture has all the “boring” digital stuff — an ESP32, the LED drivers, and the digital-to-analog converters. The next level up has the more visually interesting analog circuits, built mainly “dead-bug” style on a framework of brass wires. The user interface, mainly a series of pots and switches, lives on this level, as does a SeeedStudio WIO terminal, which is used to display a spectrum analyzer of the sounds generated.

Moving up a bit, there’s a seemingly incongruous vacuum tube overdrive along with a power amp and speaker in an acrylic enclosure. A vertical element of thick acrylic towers over all and houses the synth’s delay line, and the light pipes that snake through the sculpture pulse in time with sequencer events. The video below shows the synth in action — the music that it generates never really sounds the same twice, and sounds like nothing we’ve heard before, except perhaps briefly when we heard something like the background music from Logan’s Run.

Hats off to [Eirik] for another great-looking and great-sounding build; you may remember that his “cwymriad” caught our attention earlier this year.

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Camera-Mounted Stereo Mic Is Fluffy And Capable

October 2, 2022 by Lewin Day 10 Comments

Typically, the audio coming out of your camera is not of the greatest quality. An external mic is generally a great upgrade, and this build from [DJJules] aims to be just that.

It’s a stereo mic setup based on the work of the Office de Radiodiffusion Télévision Française, or ORTF. The ORTF stereo technique defines using two cardioid mics pointing left and right at a seperation of 110 degrees and 17 cm apart, which captures a quality stereo field that also sounds good when presented as a mono mixdown.

The build uses a simple wooden frame to hold two electret mic capsules in the required orientation. They’re wired up to a 3.5mm jack so they can be plugged straight into a mic input on a DSLR or other similarly-equipped camera. Hair curlers covered in faux fur are used as a wind shield for the mics, and gives the build a properly professional look. The frame is also given a mount so it can easily sit on a camera’s cold shoe fitting. Alternatively, a screw mount can also be used.

Good audio is absolutely key to making good content, and having quality mics is definitely what you need to achieve that. We’ve featured some other great DIY mic builds over the years, too. Video after the break. Continue reading “Camera-Mounted Stereo Mic Is Fluffy And Capable” →

three sensory bridge audio spectrum analyzers, one in use with a lit LED array plugged in, the other facing the camera and leaning against the third, all on a table

The Sensory Bridge Is Your Path To A Desktop Rave

September 26, 2022 by Abe Connelly 7 Comments

[Lixie Labs] are no strangers to creating many projects with LEDs or other displays. Now they’ve created a low latency music visualizer, called the Sensory Bridge, that creates gorgeous light shows from music.

The Sensory Bridge has the ability to update up to 128 RGB LEDs at 60 fps. The unit has an on-board MEMS microphone that picks up ambient music to produce the light show. The chip is an ESP32-S2 that does Fast Fourier Transform trickery to allow for real-time updates to the RGB array. The LED terminal supports the common WS2812B LED pinouts (5 V, GND, DATA). The Sensory Bridge also has an “accessory port” that can be used for hardware extensions, such as a base for their LED “Mini Mast”, a long RGB array PCB strip.

The unit is powered by a 5 V 2 A USB-C connector. Different knobs on the device adjust the brightness, microphone sensitivity and reactivity of the LED strip. One of the nicer features is its “noise calibration” that can record ambient sound and subtract off the background noise frequency components to give a cleaner music signal. The Sensory Bridge is still new and it looks like some of the features are yet to come, like WiFi communication, accessory port upgrades and 3.5 mm audio input to bypass the on-board microphone.

The stated goals of the Sensory Bridge are to provide an open, powerful and flexible platform. This can be seen with their commitment to releasing the project as open source hardware, providing firmware, PCB design files and even the case STLs under a libre/free license. Audio spectrum analyzers are a favorite of ours and we’ve seen many different iterations ranging from ones using Raspberry Pis to others use ESP32s.

Video after the break!

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Know Audio: Stereo

September 21, 2022 by Jenny List 16 Comments

In our occasional series charting audio and Hi-Fi technology we have passed at a technical level the main components of a home audio set-up. In our last outing when we looked at cabling we left you with a promise of covering instrumentation, but now it’s time instead for a short digression into another topic: stereo. It’s a word so tied-in with Hi-Fi that “a stereo” is an alternative word for almost any music system, but what does it really mean? What makes a stereo recording, and how does it arrive at your ears?

From West London Trains, To 3D Audio

A steam train passing through a station, from a distance in black and white — The driver of this Great Western Railway train had no idea that he was making audio history.

As most of you will know, a mono recording uses a single microphone and a single channel while a stereo one uses two microphones recording simultaneously a left and right channel. These are then played back through a pair of speakers, and the result is a sense of spatial field for the listener. Instruments appear to come from their relative positions when recorded, and the sense of being in the performance is enhanced.

Stereo recording as we know it was first perfected as one of the many inventions credited to Alan Blumlein, then working for EMI in London. We have one of his stereo demonstration films in “Trains at Hayes“, filmed from the EMI laboratories overlooking the Great Western Railway, and featuring a series of steam-hauled trains crossing the field of view with a corresponding stereo sound field. His work laid down the fundamentals of stereo recording, including microphone configurations and what would become the standard for stereo audio recording on disk with the channels on the opposite sides of a 45 degree groove. Continue reading “Know Audio: Stereo” →

Equalize Your Listening With HiFiScan

September 12, 2022 by Jenny List 28 Comments

Audiophiles will go to such extents to optimize the quality of their audio chain that they sometimes defy parody. But even though the law of diminishing returns eventually becomes a factor there is something in maintaining a good set of equipment. But what if your audio gear is a little flawed, can you fix it electronically? Enter HiFiScan, a piece of Python software to analyse audio performance by emitting a range of frequencies and measuring the result with a microphone.

This is hardly a new technique, and it’s one which PA engineers have used for a long time to tune out feedback resonances, but an easy tool bringing it to the domestic arena is well worth a look. HiFiScan is a measuring tool so it won’t magically correct any imperfections in your system, however it can export data in a format suitable for digital effects packages.

Naturally its utility is dependent on the quality of the hardware it’s used with, but the decent quality USB microphone used in the examples seems to give good enough results. We see it used in a variety of situations, of which perhaps the most surprising is a set of headphones that have completely different characteristics via Bluetooth as when wired.

If audio engineering interests you, remember we have an ongoing series: Know Audio.

2022 Hackaday Prize: Boondock Echo Connects Your Radios With The Cloud

August 27, 2022 by Dave Rowntree 6 Comments

[Mark J Hughes] volunteers as a part of a local community fire watch which coordinates by radio. The La Habra Heights region of Los Angeles is an area of peaks and valleys, which makes direct radio connections challenging. Repeaters work well for range improvement, but in such areas, there is no good place to locate these. [Mark] says that during an emergency (such as a wildfire) the radio usage explodes, with him regularly tracking as many as eight radio frequencies and trying to make sense of it, whilst working out how to send the information on and to whom.

This led him together with collaborator [Kaushlesh Chandel] to create Project Boondock Echo, to help alleviate some of the stress of it all. The concept is to use a cheap Baofeng radio to feed into a gateway based around an ESP32 audio development kit. Mount this in a box with a LiPo based power supply, and you’ve got yourself a movable radio-to-cloud time-shift audio recorder.

By placing one or more of these units in the properties of several of the community group radio operators, all messages can be captured to an audio file, tagged with the radio frequency and time of transmission, and uploaded to a central server. From there they can be retrieved by anybody with access, no matter the physical location, only an internet connection is needed.

The next trick that can be performed, is to reverse the process and queue up previous recordings, and send it back over the cloud to remote locations for re-transmission via radio into the field. This is obviously a massive asset, because wherever there is some urbanization, there is likely an internet connection. With the addition of a Boondock Echo unit, anyone that has a receiver within a few miles can be fully connected with what’s going on outside the range of direct radio communications.

Source for the ESP32’s firmware as well as the web side of things can found on the project Boondock Echo GitHub, complete with some STLs for a 3D printed box to sit it in. Like always, there’s more than one way to solve a particular problem. Here’s an amateur radio repeater based using an RTL-SDR and a Raspberry Pi.

This Simple Media Player Will Inspire Beginners And Invite Experimentation

August 16, 2022 by Dan Maloney 4 Comments

While it would have been considered science-fiction just a few decades ago, the ability to watch virtually any movie or TV show on a little slab that fits in your pocket is today no big deal. But for an electronics beginner, being able to put together a pocketable video player like this one would be quite exciting, and might even serve as a gateway into the larger world of electronics design.

For inspiration, [Alex] from Super Make Something on YouTube looked to the Rickrolling keychain media players we featured back in January. His player is quite a bit larger and more capable, with a PCB design that allows the player to be built in multiple configurations, from audio-only to full video and a LiPo battery. The guts of the player center around an ESP32 module, with an audio amp and speakers plus a 1.8″ LCD screen with SD card reader for storing media files. Add in a few controls and switches and a little code, and you’ll be playing back media files in a snap. Build info and demo in the video below.

It may be a simple design, but we feel like that’s the whole point. [Alex] has taken pains to make this as approachable a build as possible. All the parts are cheap and easily available, and the skills needed to put it together are minimal — with the possible exception of soldering down the ESP32 module, which lacks castellated edge terminals. For a beginner, getting a usable media player by mixing together just a few modules would be magical, and the fact that it’s still pretty hackable afterward is just icing on the cake.

Continue reading “This Simple Media Player Will Inspire Beginners And Invite Experimentation” →