Music gear

Pragmatic digital amps and microphones

August 26, 2014 — July 8, 2024

diy

hardware

making things

music

Assumed audience:

Prosumer audio geeks

If you find that K-Mart earphones are garbage, but $15K stereo amps are over-engineered, then this is the page for you.

1 Headphones/earphones

On the road: As far as my ear canals go, after extensive experimentation I can tell you that the best bang for my buck is in-canal earphones. My current preferred option is the Shure SE215 for jack connection or if I must use Bluetooth, the Shure BT-2 Bluetooth version. The original model, the Shure BT version 1, sounds like a Shenzhen pirate knock-off of a Shure product; avoid. A just-about-acceptable substitute for the Bluetooth adapter is the MEE audio BTX2, which is a bit cheaper and still uses the Shure earbuds.

I had some higher-end Shure earbuds, and they were somewhat better, but the ROI tails off rapidly, especially for something which I will carry with me everywhere and lose at a fairly high rate. I will save the huge expenditure for things I leave at my desk.

The difficulty in changing earbud batteries varies. I wonder how the battery change will go in my Shure BT-2, if I can keep it without losing it long enough to need to change a battery. (Aspirational battery changer, me.) Update: the plastic on the earhooks rotted pretty much just as the battery died, so I gave up on repairs and put the Shure eartips on the aforementioned MEE BTX2. For reference, it was approx 18 months of daily intense usage to destroy them.

At a slightly higher price point, the Apple Airpod Pro 2 are pretty good. Their active noise cancellation is pretty good and the integration into the Apple ecosystem is nice. They are cursed by weakness to wind. Wearing these on a bike requires me to wear a headband. If a stiff breeze picks up when I am walking, the microphone is useless.

IEEE reviewed various other earphone options including cheap Chinese imports such as DQSM D2 (USD168), the Tennmak Crazy Cello (USD50), and the LKER i8 (USD37),

All provide good, if not perfect, sound at low cost.

I do not always agree with IEEE but this is a compelling argument to test at least.

For the office, I wear Sennheiser Momentum 2.0 over-ear headphones. These advertise unambiguously that I cannot hear you, and in fact I cannot because the audio cancellation is helpfully good. Battery lasts all day in wireless mode, and the voice microphone is good enough for phone calls. New models have come out since I bought these; I wonder if they are better? They sure cost more.

2 Speakers

You know, for playing audio loudly? I would like ready access to a selection of sound systems for musical mayhem.

2.1 Home monitors

TBC.

2.2 Gig

I have a QSC K.2 sound system I use for parties for 150 or so people. I love ’em. Trouble free, very smart, portable, light, and they run off a 10 amp circuit because they are class D. Worth the price bump in saved labour.

2.3 Zany DIY

With special attention paid to building sound systems for small mountain villages in Daerah Sunda.

Cory Doctorow points at some lightly modded consumer class-T gear
Glenn Zorpette does a cheapo hifi rundown
James Nichols advises:

Yes — class D amps are better and cheaper than ever. This is the smallest, cheapest, and most surprisingly reliable option. Otherwise I just bought one of these and it really is almost 2 x 100W. Hypex is much more expensive, but actually proper hi-fi. These cheap $20 boards are good enough but totally expendable if you want them to be. Also of course — the two boards I linked you to are both 12-30V (ish), which means they are 100% battery suitable. Typically the best configuration is to put two 12V batteries in series to get 24V — at higher voltages the boards are more efficient. If you want to run off mains power, then that Yuan-Jing site has power supply options.

Updated: see also sure-electronics.com.

3 Audio interfaces

For getting analogue sound in and out of your digital device.

3.1 Firewire in the age of USB

Possible; you must go via Thunderbolt.

3.2 Cheap and cheerful

audioinjector/flatmax in Sydney make a variety of multi-channel raspberry-pi-focused soundcards for your embedded audio needs. e.g. 8 channel monster Octo. Kickstarter price for these babies is USD44, which is impressive.
Blokas make pisound which aims for high resolution audio (24bit, hi sample rate) + MIDI output. The spec claims 110db noise floor in optimal conditions, so this is actually 18 bits. Regardless, 110db is not bad for a noisy embedded device. Has neat puredata integration using the pisound app.
CM6206

is a highly integrated single chip USB audio solution. All essential analogue modules are embedded in CM6206, including 7.1CH DAC and earphone buffer, 2CH ADC, microphone gain, PLL, regulator, and USB transceiver. It is very suitable for high-end USB external audio box, USB multi-channel Headset or USB multi-channel speaker set.

I am not convinced about the high-end thing, especially for inputs (bare minimum it would need to be competently isolated). However, cheap. So cheap. Available on, e.g., ebay.

3.3 Medium

USB microphones for lazy recording? See, e.g. elgato’s USB Wave series.

3.4 Fancy

Sound Devices MixPre series are mixers/recorders/class compliant sound cards. Minimalist, apparently nice sounding. Expensive. A cheaper, maximalist alternative is e.g. a Zoom recording mixer, such as the Zoom Livetrack. My experience with Zooms has been a little lo-fi, but I am told they sound better these days?

3.4.1 RME Fireface

I have an RME Fireface UCX.

I constantly need to know how to put it in and out of class compliant mode. Relevant manual excerpt:

Operation Activation of the Class Compliant mode: Connect the UCX to power and switch it on. Turn the encoder knob in Channel mode until SU appears in the display. Press the knob once to activate Level mode. Turn the knob until CC is shown in the display, then press and hold the encoder until the display shows on (pressing the knob again will make the display show oF, indicating CC mode is inactive). The unit will reboot, all LEDs will light up, after which it will be in Class Compliant mode.

Check if CC mode is active: CC mode is active when turning the encoder lists not only CC, but also C8 and CA in the display.

In class compliant mode it works with iOS and Linux; in normal mode it works with macOS and Windows. Other combinations lead to confusion.

4 Cheap microphone hacks

4.1 Lo-fi

Leafcutter John wild hacks
DIY electret microphone upgrade

4.2 Higher-fi

FACT profiles LOM field-recording microphony.

5 Cheap snakes/multicores

Copper is expensive. And multicore mixing snakes Can I turn a CAT5 cable into a multicore? CAT5 is freely available second hand and easily replaceable. Real multicore is expensive, hard to fix and hard to find in, e.g. Indonesia where I have been asked about this a lot.