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Posts Tagged ‘Microphone test’

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For a long time I have used Rode NT1a for nature recordings. It is a very good mic to capture the finest details in quiet soundscapes. But at the same time there is something missing in the sound quality, especially when it comes to low frequency and „audio depth“.
Last summer I got interest in IRT cross mic setup, so there was a perfect opportunity to invest in other microphones. There were not many mics to choose from with extra low self noise. Nevaton in Russia makes very interesting low noise & high sensitive mics. But my experience with MC50Quad was it did not capture the finest details of the silence as clearly as NT1a or MKH20. So I decided to invest in Lewitt LCT540s which I got for a acceptable nice price (See comparison)
I built a special shock mount for the LCT540s inside Rycote AE windshields (ORTF WS kit P/N:080210). That AE windshield is wider than normal WS windshield, especially made for stereo rigs so it is very good for large capsule, side address mics like LCT540s. Low handling noise is important for less rumbling wind noise and when it comes to LCT540, it is slightly better than NT1a.
Everything was ready for a field test in late Mars so I followed the silence into the country side. I was lucky with the weather, dry and calm, maybe too calm because it makes the silence too quiet for this field test. Anyway sometimes light gust gently wipes the top of trees and bushes which sounds fantastic in the headphones, moving slowly from left to right. It was much easier to feel the depth of the field with LCT540 than it has been with NT1a.
Nothing interesting was audible until in the early morning, about half hour before sunrise, when two Rock Ptarmigan started to „sing“. First in distance, but suddenly, maybe because of curiosity, they flied closer to the microphones and walked around the rig. The following recording is actually this moment.
It was recorded in IRT cross, which gives lot of opportunities in mixing. It gives me four different stereo recording in to four directions, all in NOS, plus many other versions too with different channel mix. It can be useful when looking into specific soundscape. It is for example possible to avoid traffic noise or other unexpected sounds from one or another direction.
The two first enclosed recording below have go through noise reduction process (above 3Khz). But the last one is a short peace without noise reduction, just as it comes from MixPre6, so you can hear the LCT540 self noise, which is about 2dB higher than in NT1a. It was recorded with 48dB gain and HPF at 40Hz. In post, I only normalize the gain level up to max, which rise the gain about +10dB. I did not change the EQ so audience can hear the sound quality at the low frequency. My feeling is that LCT540 have almost same low frequency quality as the MKH series & Nevaton which is very good
This is two versions of the same recording where I mix four channels differently into stereo. Counting channels 1-2-3-4 clockwise to L-R-Ls-Rs and the second one L-R-Rs-Ls (which is usually normal IRT setup).
This is a „high dynamic“ recording of silence, so I don´t recommend it played loud. It might destroy some speakers (ears too) if it is played too loud without attention.
Good monitor headphones are recommended or quality open headphones while listening at low to medium level.

Recording L-R-Ls-Rs
(mp3 256Kbps / 35,6Mb)

Recording L-R-Rs-Ls
(mp3 256kbps / 35,6Mb)

Short version of recording L-R-Ls-Rs without NR
(mp3 256kbps / 7,4Mb

Recorder: Sound devices MixPre6
Mics. Lewitt LCT540s (IRT cross setup) Running on 70m Sommer Mercator CAT7 S/STP cable
Pix: Canon EOS M50
Weather: Calm, dry, between -2 to +4°C, about 7:30 o´clock

Location: 64°40’23.7″N 21°37’43.7″W

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It is difficult to compare LCT540 and NT1a in details. I am not sure which one is better for silence recordings. Both have same specification of lowest self noise on the market, they have their own characteristics and after my NT1a mod, they seems to have slightly different polar pattern.
I record this audio samples at 24bit/48khz with 45dB gain (40Hz HPF) on MixPre6
In post I increase the gain approximately another 45dB and normalized to -5dB
The outcome is shown on the spectrograms on recording A and recording B. The LCT540 is above. NT1a below.

NT1a is extremely well focused in the mid-range 500hz – 5Khz. which is exactly the frequency where most common birds sing. So NT1a is very good for nature recordings. But sometimes NT1a sounds „flat“ because NT1a is rather poor on low frequency, sometimes like out of phase (which could be as well caused of wrong setup).
I have not a long experience recording with LCT540s, but at the moment the overall sound quality seems to be better than NT1a, especially in lower frequencies which give better „juicy“ sound and „depth feeling“. But at the same time it is not as „clear“ as NT1a in the mid range.

Following audio samples will give some insight how LCT540s compares to NT1a in silence. You can clearly compare the mics self noise which sounds almost equal.. You can also hear how this two microphones pick up the details in two alarm clocks and a pocket radio at the lowest level in ca 2,5m distance, inside ca 45m2 garage. Other background sound is a light gust outside which swipe the garage walls and roof, a fly in the window and a traffic in air and ground in the county. Anyway this is a silence which most people will barely hear anything else than just their own heartbeat. See pictures

How do they withstand humidity or handling noise in windscreen? I can only say this.
Both need DIY shock mount if they should be fit in Rycote windshield. Both are sensitive for handling noise especially NT1a. High humidity is usually not a problem for microphones in Iceland, but there are stories about problem with NT1a in other countries.
I will update this information/comparison as soon as I have got more experience with LCT540s. You can also search for NT1a and LCT540s on this website and listen to nature recordings.

Listening with quality headphones will give best result.

Lewitt LCT540s Recording A (mp3 256kbps / 7Mb)

Rode NT1a Recording A (mp3 265kbps / 7Mb)

Lewitt LCT540s Recording B (mp3 256kbps / 4,8Mb)

Rode NT1a Recording B (mp3 256kbps / 4,8Mb)

Short comparison of both LCT540S & NT1a

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