First Dawn

A drainpipe at Pembroke College after heavy rain.

Pembroke College Drainpipe

My former recording setup versus my new one. The 'Hydra' is an 8 capsule EM272 stereo module built for me by Micbooster. I'm using it with a recently acquired Olympus LS-10 recorder. The Sony PCM-A10 I would normally use couldn't supply enough power to drive 8 capsules and the preamps were too noisy. 

I bought a 9v battery box to use with this setup but bizarrely I don't need to use it with the Olympus. It seems to somehow be powering 8 capsules from 3v plug in power just fine!

The PCM-A10 with a normal EM172 stereo pair is up first, followed by the 'Hydra' and LS-10. Note the reduced self-noise. This is coming from the combination of the microphone and recorder, as using the standard stereo pair with the Olympus sounds pretty much the same as the Sony.

Sony PCM-A10 Primo EM172 Vs Olympus LS-10 'Hydra'

Summer Road

My 8 x EM272 rig (going via a 9v battery box) is lower noise than a normal EM272 pair but it is also quite a bit more sensitive (around 7.5dB). 

In a very dynamic situation like a thunderstorm, I like to record at the lowest possible level to avoid clipping. On the Sony PCM-A10 you can set the gain right down to level 3 without introducing any additional noise (with a normal EM272 stereo pair). Levels 1 and 2 add quite a bit of recorder self noise.

I wanted to test recording at level 1 with the 8 capsule rig, to see if the lower noise of that rig would mitigate the effects of the increased recorder noise.

In this clip you hear a standard EM272 pair recorded at level 15, followed by the 8 capsule rig at level 1. Recordings were made simultaneously to two separate Sony PCM-A10 recorders and subsequently normalised to the same level using a 1kHz test tone played from my phone.

The result was positive. The 8 capsule rig still has less noise, despite the added recorder noise due to the low gain level.

Sony PCM - A10 Low Gain With 8 X EM272 Capsules

Primo EM272 capsules to my ear suffer from sounding a bit harsh in the higher frequencies when compared to other popular field recording microphones. When you compare different microphones side-by-side, it is striking how different they sound.

What you hear in this is same brief clip recorded with a pair of Clippy EM272 omnidirectional microphones. Each time the clip is repeated, you hear a different EQ profile meant to emulate different omnidirectional microphones popularly used in field recording: Sennheiser MKH 8020s, DPA 4060s, Lom mikroUsi, Lom Usi/Clippy EM272 (i.e. no EQ) and an EQ that is sort of a hybrid of the characteristics of each that I like (the warmth of the mikroUsi, the sparkle of the 4060s, the 'bigness' of the 8020s).

These EQ profiles were created using various side-by-side comparison clips of the microphones mentioned (some mine, some from elsewhere) and the EQ Match feature in FabFilter.

I'd be interested to hear your comments on which you prefer. I have deliberately not labelled the clips to avoid bias.

Primo EM272 EQ Profile Experiment

Various tones, drones and atmospheres recorded during the middle of a calm night, on the deck of a ferry crossing the English Channel.

Ferry Atmospheres

Spring Thunderstorm

Enigmatic Grille

Ferry Morning Wake Up Calls

St Ebbes Primary School Choir

After The Storm

Oldham Street, Manchester. Ambience from the top floor of an apartment building. I recorded this from the rear of the apartment  which was surrounded on all sides by the neighbouring buildings. Almost all the sounds are indirect, travelling up from the street and over the buildings giving everything a soft, reverberant quality. I love these kind of indirect soundscapes.

Oldham Street Rooftop

A busy Sunday afternoon in Manchester's Northern Quarter. Recorded from the balcony of a 5th floor apartment on Oldham Street.

Northern Quarter Ambience

Ki Bagus Baghaskoro with the Oxford Gamelan Society performing Eka Cakra and the Spiced Warrior at St John's College, Oxford,27/11/2023. Part of the World's Music at Oxford series.

Eka Cakra and the Spiced Warrior

The Zoom F6 occasionally displays the error 'exceeding maximum input levels' when recording high SPL sound sources in 32-bit mode. Other users have reported the same problem but on analysis afterwards, the sound isn't clipped or distorted in any way. On this test I'm using a pair of Clippy (EM172) microphones right on top of a ride cymbal. The first couple of hits are quiet but then for all the subsequent ones the error came up on screen so I was expecting either clipped or distorted sound afterwards. However, I was able to normalise the audio to get rid of the clipping, and there is no audible distortion. This looks like maybe a software problem, where the unit is displaying the error at the wrong time.

Zoom F6 Exceeding Maximum Input Level

2 x AT4022, 1 x BP4025 (stereo microphone) and 2 x Clippy recorded at unity gain on the Zoom F6 and normalised in reaper (+22db for AT4022, +24db for BP4025, +16db for FEL Clippy). 

AT4022 sound the quietest to me, with BP4025 very slightly more noisy, and the Clippy microphones quite significantly more noisy,

Audio Technica AT4022, Audio Technica BP4025, FEL Clippy (EM172) Noise Test

Another test of the BP4025 vs Primo EM172 (FEL Clippy XLR). This time in a more real-world setting. 

I have noticed how bright the EM172s are in comparison to the BP4025 (and AT4022 which I tested earlier). This led me to think they can stand a little EQ adjustment to try to reduce the noise, which is naturally higher than the BP4025.

1. Primo EM172 stereo pair
2. BP4025
3. Primo EM172 with EQ applied (-4db reduction in the 5-15khz range)

1 and 2 were recorded simultaneously to a Zoom F6 and later normalised. 3 is a copy of 1 with EQ applied.

Conclusion 1: BP4025 is naturally more quiet than the EM172 but has a more narrow stereo image. However, applying some EQ to the EM172 brings the noise level even lower, and without any negative impact to the overall sound. To my ears, it sounds even more natural now. 

Conclusion 2: I didn't need to buy the BP4025 to achieve lower noise recordings. Damn!

EM172 VS BP4025 VS EM172 With EQ

One clip is Sennheiser MHK 8020, the other clip is Primo EM172 with EQ applied. Can you tell the difference?

As of August 2020, a pair of Sennheiser MKH 8020 costs more than £2,000 in the UK. A pair of Primo EM172 microphones can be purchased ready-made for less than £100, or built for even less. 

Original recording by Vicki Powys used with permission. You can read more about the setup of the original recording here: https://caperteebirder.com/?page_id=333

Sennheiser MKH 8020 VS Primo EM172 Blind Test

2 x Clippy microphones in a cupboard recording to an Olympus LS-P4. Same source recorded at 7 different gain settings (1, 5, 10, 15, 20, 25, 30) and normalised in post (adding 70db to the lowest gain setting, 5db to the highest). Recorded at 24/48.

This shows a very clear linear progression in the reduction of noise. I often record at level 15 in quiet ambiences but this shows there's something to be gained (in terms of HF noise reduction) by cranking it up to 20 so long as there's no likely to be any loud sound sources that will clip the recorder.

Olympus LS - P4 Self - Noise Test

This test is comparing the self-noise of the Sony PCM-A10 and the Olympus LS-P4 at various gain settings using external microphones (Clippy EM172). Both recorders allow gain settings from 1-30. I recorded the same sound source (quiet ticking clock) at levels 1, 5, 10, 15, 20, 25 and then 30 simultaneously on both recorders and then normalised the levels in Reaper. I then had to do quite a bit of manual correction of the levels because there were some low frequency sounds that were louder than the ticking clock and which were messing with the normalisation process. Recordings were made at 24/48 WAV.

In this recording you first hear the Sony at gain level 1, followed by the Olympus at gain level 1 and so on up to level 30.

As shown in an earlier test the Olympus exhibits much higher levels of self noise at lower gain settings, with a noticeable improvement coming at level 20. This means that when recording quiet scenes, it is worth taking the risk of setting the gain high to minimise the recorder self noise.

The Sony behaves quite differently. At gain level 1 the noise is quite terrible  but at level 5 there is a sudden improvement and in fact there is almost no difference between the noise at level 5 and level 30. This seems to suggest that you can be much more conservative with setting the gain on the Sony to avoid clipping, and increase the levels later in post with no apparent self-noise penalty.

Sony PCM - A10 VS Olympus LS - P4

Another test of the Sony PCM-A10 at different gain settings using external microphones (Clippy EM172 stereo pair). Recordings of two different subjects at low and high gain to compare the recorder self-noise. Tracks normalised in post afterwards. Recorded at 24/48.

Clip 1: Indoors with windows shut. Birds audible through the windows. Recorded at input level 5.
Clip 2: Same as above recorded at input level 25
Clip 3: Outdoor ambience recorded at input level 5.
Clip 4: Same as above at input level 20 (highest I could go without the sparrows clipping the recording!) 

A gain setting of 5 on the PCM-A10 is very, very low in case it isn't clear. There was virtually nothing registering on the meters while I was recording.

I hear zero difference in noise for the recordings at very low and very high gain settings. This is incredible as it means you can set your levels very conservatively to avoid clipping and increase levels in post later with no fear of losing the signal in the noise.

Sony PCM - A10 Gain Test

More tests of the Sony PCM-A10 at extremely low gain levels. I recorded a few seconds of test tone followed by 20+ seconds of a quiet room at gain levels 1, 2, 3, 4 and 5, and then level 25 as a high gain level for comparison (highest gain should have the best noise performance).  The recordings were then normalised in Reaper, resulting in gain being added to each clip of: +40.8dB, +39.1dB, +37.7dB, +35.7dB, +34.6dB and finally +2.87dB (gain level 25).   

Hopefully what you can hear in this is that levels 1 and 2 have a high level of noise, but then it suddenly drops off at level 3, and levels 3, 4, 5 and 25 all have nearly identical levels of audible noise.

My conclusion is that when recording a dynamic source such as a thunderstorm, I can safely go all the way down to gain level 3 to minimise the chance of clipping, while not adding significant noise when I later raise the levels in post.

Sony PCM - A10 Gain Test (Extremely Low Levels)

Heavy Rain Against The Window

In this test I compare the self-noise of Clippy EM172 into a Sony PCM-A10 recording at extremely low gain (level 3 out of 30) versus the same microphones into a Zoom F6 recording in 32-bit float mode.

Clip 1: Sony recording of outdoor scene at original volume
Clip 2: Same Sony recording normalised (+24.2dB)
Clip 3: Zoom F6 recording of the same scene normalised to the same level
Clip 4: Sony recording of indoor scene normalised (+24.2dB)
Clip 5: Zoom F6 recording of the same scene normalised to the same level

My conclusion is that when using Clippy EM172 microphones (14dBA self noise, -28dB sensitivity), low noise preamps such as those on Zoom F series recorders or Sound Devices are overkill. In addition, if you want to avoid clipping (a reason for using 32-bit float) you can simply set the gain level on the PCM-A10 very low, and when you bring the noise levels back up there is no noise penalty (you should avoid going below level 3 however as I have demonstrated in a previous test that the noise increases considerably below level 3).

Sony PCM-A10 Low Gain Vs Zoom F6 32-Bit Float

Grey Squirrel Alarm Calls

Kitchen Window, November Morning Ambience

I'm always looking to shrink the size and weight of my rig. I just love carrying the minimum amount of equipment!  I did this test to see how small I could go with microphone separation without sacrificing quality. All configurations were Clippy EM172 stereo pair to Sony PCM-A10.

My conclusion is that AB40cm rig with simple Rycote lav wind protection gives me a great sound with a very small and light footprint but not great wind protection. The quasi-binaural rig gives perhaps a more accurate stereo field with the advantage of excellent wind protection (it is housed in the equivalent of a blimp with proper windjammer). To get better wind protection for the AB40cm rig would require a massive and heavy (by my standards) blimp.

1. AB20cm - narrow, too narrow...
2. AB30cm - getting wider, pretty nice...
3. AB40cm - wider still but nice balance of width and centre-image?
4. AB60cm - very wide but hole in the middle?
5. Quasi-binaural (20cm spacing with foam cylinder baffles) - improved placement of sounds in the stereo field?

Would be very interested to hear what other folks think. Please comment if you care to.

Omni Spacing Test

Quick self-noise comparison of Primo EM258 (aka Lom mikroUsi) vs Primo EM172/272 (aka Clippy, aka Lom Usi).

EM258 is rated at 20dBA and EM172/272 is rated at 14dBA. The difference is noticeable indoors, but not so much outdoors in the situations I have tried so far (not super quiet).

EM258 EM172/EM272 Self-Noise Comparison

Recording of a quiet suburban scene. EM172 followed by EM258. Simultaneous recording to 2 x Sony PCM-A10 recorders.

EM172 Vs EM258 Self-Noise Ambience

Two simultaneous recordings made a while back when I was temporarily in possession of a pair of Audio Technica AT4022 microphones and a Zoom F6 recorder. The AT4022s have a similar performance in terms of self-noise to the Sennheiser MKH 8020s but come in at about a third of the price.

I record everything with Primo EM172-based microphones at the moment but keep getting tempted by lower self-noise (but more expensive, larger and heavier) microphones. However, a test like this makes me question how worthwhile that would be...

One clip is the AT4022s, the other is the EM172s with some noise reduction applied (Izotope RX8 Spectral De-Noise). The difference is very subtle and I doubt it would be noticeable at all outside of an AB comparison like this. Also, in 80-90% of recording situations I find myself either the subject or the environmental noise is much louder than in this test (the gain is really cranked here), and so you wouldn't be hearing any self-noise from the Primo capsules anyway.  Combine that with the fact that the Primos are tiny, weigh almost nothing and are cheap to replace, I can see why so many people love them!   

Let me know in the comments which you think is which.

Audio Technica AT4022 Vs Primo EM172 Blind Test

I wanted to test whether the Primo EM258s (same capsules used for the Lom mikroUsi) have low enough self-noise for recording in a quiet, natural environment. I recorded the following clips in the middle of winter in a relatively quiet local wood. I set the gain so that when played back at maximum volume on a computer or phone, the clips should be approximately the same volume as the sound was in reality. That meant setting the gain lower for the EM172s, which are a bit more sensitive than the EM258s.

The first section presents first the EM258s and then the EM172s without any gain added. This was a very quiet environment, so even at this very low playback volume, the noise of the EM258s (clip 1) is pretty noticeable, whereas the the EM172s sound pristine.

The next section presents the same two clips again with 12dB of gain added, which is probably a bit of a more 'typical' playback volume. The EM258s are very noisy now, with the EM172s still sounding great. There is a small amount of noise, but really very little.

The third section presents the same two clips again still with the 12dB of gain, but also with some noise reduction (Izotope RX8 spectral de-noise). Despite the noise reduction, the EM258 self-noise is still pretty noticeable. There has also been quite a loss of high frequency content meaning the birds are harder to hear now. The EM172s however fare much better. The self-noise is completely inaudible, and the high frequencies although attenuated, are still sufficiently present. In fact, you could say it makes them a bit more flat and natural sounding, in line with higher-end mics like the Audio Technica AT4022s, or Sennheiser MKH 8020s. 

Probably a bit of an obvious outcome based on the specs of the microphones, but it has confirmed for me that I should always have my EM172s with me for recording in quieter environments. They are more sensitive and have lower self-noise than the EM258s. In addition, they naturally have a boost in the high frequencies compared to other microphones, meaning you can apply significant noise reduction but without drastic loss of high frequency content. 

Apologies for my swallow, and the odd little crackling sounds throughout. I was wearing the microphones on the straps of my backpack and picking up some human self-noise!

EM258 And EM172 Self - Noise Test In A Forest

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Stereo soundscape recordings. Sometime nature, sometimes people, sometimes machinery. Sometimes quiet things like a single branch creaking in the wind on Dartmoor, sometimes odd moments in the city. Mostly local, but sometimes travelling. 

Popular tracks by Douglas Langley