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doc:appunti:linux:audio:audio_recording [2020/12/28 17:21] – [Web References] niccolodoc:appunti:linux:audio:audio_recording [2020/12/28 18:22] (current) niccolo
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 Unlike capacitor ones, electret microphones **do not require polarizing voltage**, but generally they contain an integrated preamplifier that **does require power**. In this cases a **TRS jack** can be used, where the ring carries power via a resistor from, normally, a 5 V supply in the computer (often incorrectly called //polarizing power// or //bias//). Generally these microphones built to be plugged into computers and electronic audio devices, have a **TRS 3.5 mm jack**, carrying the mic signal and the required current. Unlike capacitor ones, electret microphones **do not require polarizing voltage**, but generally they contain an integrated preamplifier that **does require power**. In this cases a **TRS jack** can be used, where the ring carries power via a resistor from, normally, a 5 V supply in the computer (often incorrectly called //polarizing power// or //bias//). Generally these microphones built to be plugged into computers and electronic audio devices, have a **TRS 3.5 mm jack**, carrying the mic signal and the required current.
- 
-====== Problem: silence gaps using a cheap USB dongle ====== 
- 
-I was **unable to use the microphone connector** on my Acer TravelMate, so I tried to use an USB dongle, marked **LinQ**. The device was detected by the Linux Kernel 4.9.0: 
- 
-<code> 
-usb 2-1.3: new full-speed USB device number 9 using ehci-pci 
-usb 2-1.3: New USB device found, idVendor=0c76, idProduct=1607 
-usb 2-1.3: New USB device strings: Mfr=0, Product=1, SerialNumber=0 
-usb 2-1.3: Product: USB Headphone Set 
-input: USB Headphone Set as /devices/pci0000:00/0000:00:1d.0 
-    /usb2/2-1/2-1.3/2-1.3:1.3/0003:0C76:1607.0004/input/input92 
-hid-generic 0003:0C76:1607.0004: 
-    input,hidraw2: USB HID v1.00 Device [USB Headphone Set] 
-    on usb-0000:00:1d.0-1.3/input3 
-</code> 
- 
-{{ linq-usb-audio.png?direct&100|LinQ USB audio dongle}} 
-The USB audio adapter worked quite nicely at playing audio, I use it on a QNAP TS-120 NAS, transformed into a media player installing Debian GNU/Linux on it. The Linux kernel and the **ALSA audio subsystem** works well on setting the levels for **playback**. 
- 
-Once started Audacity, I was able to select the microphone line of the USB dongle as a **capture device**: 
- 
-{{audacity-select-usb-audio.png?direct&260|}} 
- 
-Recording a sample track revealed an annoying problem: about **every 0.4 seconds** you can see a **gap of silence** in the audio track of about **two hundredths of a second**. The audio track is unusable! 
- 
-{{audacity-track-gaps.png?direct&400|}} 
  
 ====== Wireless UHF microphone ====== ====== Wireless UHF microphone ======
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 See this article about **[[audio_recording_usb_adapter]]**. See this article about **[[audio_recording_usb_adapter]]**.
 +
 +====== Problem: silence gaps using a cheap USB dongle ======
 +
 +I was **unable to use the microphone connector** on my Acer TravelMate, so I tried to use an USB dongle, marked **LinQ**. The device was detected by the Linux Kernel 4.9.0:
 +
 +<code>
 +usb 2-1.3: new full-speed USB device number 9 using ehci-pci
 +usb 2-1.3: New USB device found, idVendor=0c76, idProduct=1607
 +usb 2-1.3: New USB device strings: Mfr=0, Product=1, SerialNumber=0
 +usb 2-1.3: Product: USB Headphone Set
 +input: USB Headphone Set as /devices/pci0000:00/0000:00:1d.0
 +    /usb2/2-1/2-1.3/2-1.3:1.3/0003:0C76:1607.0004/input/input92
 +hid-generic 0003:0C76:1607.0004:
 +    input,hidraw2: USB HID v1.00 Device [USB Headphone Set]
 +    on usb-0000:00:1d.0-1.3/input3
 +</code>
 +
 +{{ linq-usb-audio.png?direct&100|LinQ USB audio dongle}}
 +The USB audio adapter worked quite nicely at playing audio, I use it on a QNAP TS-120 NAS, transformed into a media player installing Debian GNU/Linux on it. The Linux kernel and the **ALSA audio subsystem** works well on setting the levels for **playback**.
 +
 +Once started Audacity, I was able to select the microphone line of the USB dongle as a **capture device**:
 +
 +{{audacity-select-usb-audio.png?direct&260|}}
 +
 +Recording a sample track revealed an annoying problem: about **every 0.4 seconds** you can see a **gap of silence** in the audio track of about **two hundredths of a second**. The audio track is unusable!
 +
 +{{audacity-track-gaps.png?direct&400|}}
  
 ====== Web References ====== ====== Web References ======
doc/appunti/linux/audio/audio_recording.txt · Last modified: 2020/12/28 18:22 by niccolo