Røde AI-Micro USB-C phone interface

I am writing this from a field recordist’s point of view, not a podcaster POV. Podcasting seems to be the design intended use case.

There’s nothing more commonplace in the modern urban setting than somebody with earbuds glommed onto the delights within their a smartphone. Pair some binaural in-ear microphones like Soundman OKMIIs with a smartphone and you potentially have an inconspicuous and high performance street field recording rig. You’ll also look like you’re poor and have a cheap phone, because everyone haz bluetooth wireless earbuds, right?

Problem is that smartphones have only mono microphone inputs, or if they are made by Apple none at all. You get cheap USB-C to 3.5mm jack interfaces, but most are mono in, providing the features of the TRRS jack you used to get. I had high hopes for the Røde AI-micro – a little bit dearer than your Chinese noname product, but more functional – offers stereo in. Røde is a well-known manufacturer of microphones, including some very low noise models – the NT2000 is legendary for a very low self-noise of 7dBA.

The Røde AI-Micro worked pretty well as designed, and will be fine for close-up voice, but as a field recorder front end it’s a bust. Compared to an Olympus LS-101 from nearly 20 years ago, it’s noisy. Very noisy.

To test this I injected a -67dBu tone at 150 ohms2 source impedance into the mic input, set to stereo, max gain. The Røde AI-Micro has more max gain than the LS10, so I had to boost the LS10 recording by 8.8dB to make the tone peak the same (to within 1dB). This ensures I am comparing like with like, with a known reference point. Both recordings were made at full gain, and neither was clipping.

These two tracks are 30 seconds of tone, followed by silence3 – the generator turned off but still terminating4 the input with 150Ω.

Røde AI-Micro

Olympus LS-10, boosted by 8.8dB to match tone levels

One listen to these, particularly the second half tells you pretty much all the field recordist needs to know.

Continue reading “Røde AI-Micro USB-C phone interface”

Ebbor Gorge, Somerset Dawn Chorus

There’s a welcome reduction in aircraft during the coronavirus pandemic, which means our soundscapes aren’t scarred by the rumble of jets. I listened to the lovely soundscape unfold, with an extract from the early part of the chorus which is more sparse, the later part which is denser and richer in sound.

It was a lovely expedition to a local nature reserve, and I am intrigued to sample other nearby soundscapes with less human-induced noise. The gorge helps shield the valley from noise, it will be interesting to see if this works on the Somerset Levels as well, which don’t have the protection of lots of limestone rock.

International Dawn Chorus Day

I joined with Locusonus and the Reveil project to broadcast birdsong from near my garden for International Dawn Chorus Day. Due to the coronavirus pandemic the choice of locations was limited. It’s good to appreciate one’s local birds, however, this blackbird sang well after he’d settled down from whatever fright woke him up at the start.

These mics aren’t the finest – basically cheap Chinese electrets because they’ll be left out in all weathers. IDCD was a still dry day, and the birds could give of their best, with human noise lower than usual. The recording extract starts at at about a quarter to six BST.

International Dawn Chorus Day – getting bird sounds indoors without opening the window

International Dawn Chorus Day 2020 is somewhat overshadowed by the coronavirus pandemic for its human listeners. The birds probably appreciate getting some peace! The Wildlife Sound Recording Society was after getting a live broadcast of this from as many members as possible. They proposed two methods of live broadcast, their preferred option using Mixlr and a more gonzo alternative using locusonus.

Mixlr seems all about tablets and mobile phones. If a project’s got a mobile phone in it I’m not interested. I loathe smartphones – jack of all trades and master of none. They don’t do stereo1, FFS… Mixlr is Cloud. I don’t do Cloud, particularly if it comes with a subscription. It’s bad  enough when Cloud goes AWOL and you’ve put effort into the platform for free. Pay for the privilege?  Nope.

So I passed on that and went to locusonus, who are doing this under the Reveil soundcamp moniker. Locusonus is funded by the French State, bless their arty dirigisme – just look at their publications. And sponsors

So arty! So French!

Reminds me of reading about musique concrete as a kid in the 1970s, IRCAM and all that, while I was piddling about with a hand-me-down Stellavox tape recorder. Mad, but inspirational. I’ll hitch a ride on French exceptionalism.

I’m lucky in that way back when I bought a Cirrus Logic sound card for a Raspberry Pi. Or perhaps unlucky in another way – I never found a good use for it till now, as the software drivers were a whole load of hurt. By the time they got incorporated into Raspbian, the card was end-of-lifed so you can’t buy them any more.  That’s Linux for you. Free as in beer but slow to integrate hardware. If you are doing this from scratch, either use a cheap audio adapter with mono audio or something like the Behringer UCA202 USB audio card – stereo line in and works great with the Pi, right out of the box.

Despite fiddling with the CirrusLogic on and off I came to the conclusion a timed bird sound recorder is better done with a Dribox and a real audio recorder and a timer. However, a Pi and the CL card is perfect for locusonus. Perfect enough, indeed, that downloading the relevant Pi SD card image, blowing it onto a SD card and firing it up on ethernet gave me an instant win2, using a set of OKMII binaural mics into the line in port with the bias enabled.  I was able to hear myself, albeit at a low level, but the locusonus software lets you ram the Cirrus programmable gain amp up to +30dB and max digital gain. Sure, it’s noisy, but showed the principle.

Now all I need is an outdoor microphone Continue reading “International Dawn Chorus Day – getting bird sounds indoors without opening the window”

Clap for Carers NHS Appreciation

Every Thursday in the coronavirus pandemic there is a clap for carers event at 8pm to show our appreciation of the workers in the NHS

You can read more about Clap for carers here. It’s a way to show appreciation for everyone who is working for us all at this difficult period.

XY recording, AT8022, Glastonbury

Chalice Well Bell sounding for a Silent Minute’s reflection

At noon and 3pm a bell in rung in the Chalice Well Gardens, Glastonbury  to invoke a minute’s silence for reflection. A wren breaks the silence, and the bell is sounded again at the end of the minute.

The bell was the old school bell, the school buildings were cleared in the 1970s which opened up the bottom of the gardens a lot.

The ritual of the Silent Minute was instigated in WW2 by Wellesley Tudor Pole, who was a key figure in the founding of the Chalice Well Trust.

OKMII binaural microphones

 

Winchester Great Hall

Fabulous reverb in Winchester Great Hall with its iconic Round Table, one of the many seats of King Arthur in the British Isles. There are probably as many true Arthurian residences across the UK as there are oldest pubs in the land 😉

Some visitors wandered over to the door on the left which leads to Queen Eleanor’s Garden and the large door closes with a resounding clang.

Winchester Cathedral ambience

The huge imposing structure of Winchester Cathedral has a fantastic long reverberation time

and some remarkable low-frequency sounds. There is some research suggesting very low frequencies induce a sense of awe, quite appropriate for a cathedral 😉

the sound of starlings massing

Winter is coming, and that means that millions of starlings are on the move, from the deep cold of Continental Europe to the relative mildness of Britain’s winters. We are surrounded by the sea, which buffers the temperatures reducing the cold in the depths of winter. They join our resident starlings to roughly double the population in winter, according the the RSPB.

A starling is nothing that special individually, but in winter they roost communally in reedbeds1 these days. They group together in massive billowing clouds called murmurations2, this is thought to be trying to confuse birds of prey, who can’t home in on individual birds.

The unquiet sound of massed starlings

Once they’ve settled in for a while a massive racket starts to built up, this is a binaural recording best on headphones. The slight dread at 4:30 is when a bird of prey came along, it silenced the starlings closest to me but most of the roost was still rapping away to each other.

I managed to get myself to within fifty yards of one of their roosts on Ham Wall, in the Avalon Marshes complex of nature reserves, sited on only peat extractions. Although the starlings tend to roost somewhere on the reserves, which site they favour varies from day to day. When you’re that close to the roost, you get to hear the damnedest noise from these guys. A starling roost is not a peaceful place – they charge around low in the reedbeds, and as the day gave way to twilight I saw a bird of prey strafe in low over the water, though I couldn’t make out whether it won its supper for the night.

It was a slight challenge to stand my ground as I was buzzed by wave upon wave of birds incoming on all points very low. They didn’t go for me, although The Birds3 movie did come to mind.

Some tips if you are going to visit a starling roost

  • Choose a still day, the starlings take more time about their murmurations if they don’t have to fight the wind or rain
  • Go early in the season – November or December. The season persists often through to March, but starling shit is a pretty noxious smell. The hum builds up to an acrid stench as time passes
  • For the same reason, keep your mouth closed if you look up at phalanxes of starlings passing overhead 😉
  • Go on a weekday – fewer people and dogs with all that goes with that…
  • Avalon Marshes has a Starling Hotline 07866 554142 that tells you where the birds roosted last night. That doesn’t tell you where they will be tonight, but it lifts the odds. It’s a dead cert if you fancy the early morning sight when they leave, however.
  • Take a torch. It’s very dark when the birds pack it in, and the cold comes as the sun goes down.
  1. In the early parts of the 20th century when the starling population was much higher and we hadn’t killed off most of the insect population they had massive urban roosts in London. ↩
  2. You can find a roost near to you on the Starlings in the UK site to see murmurations for yourself ↩
  3. Hitchcock could have done very well with the electric, eerie sound of starlings, but he synthesised the soundtrack using a Trautonium. ↩

Knud Viktor’s remarkable sound paintings from 1977 released

The Vinyl Factory has released Knud Viktor’s sound paintings– featuring creatures from the Luberon in France

The sounds are sparse, opening with a nightingale, but the sounds work into a fine narrative. Towards the end of the first track there is a great mix of some fellow moaning out into the night against a nightingale and the humming of bees