vs1053:recording from LiNE1:weak signal

Writing software that inputs and/or outputs audio and performs DSP algorithms such as filters, new codecs or audio effects.
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Posts: 21
Joined: Mon 2012-02-06 23:04

vs1053:recording from LiNE1:weak signal

Post by zulunation »

Hi All,
I am using vs1053b. It works fine when playing the music and recording from electret microphone.
I am trying to record from LINE1.
I have a piezo module with it's own amplifier (LM386). When I connect headphones to my module I hear that signal is very good.
Then I connect output of my module to the LINE1 of vs1053b.
The LINE1 is connected like on schematics. I goes through 470ohm resistor and 1uF capacitor and then to my module.
Also LINE1 is connected to ground through 10nF capacitor.

Here is my configuration code:

Code: Select all

record_gain = 1024;
sample_rate = 8000;
max_autogain = 1024;
stereo_mic = 0x06;
I do not modify the SCI_VOL register. So it has maximum volume.

When i record the signal level is very low.
I check that with headphones connected to the LEFT/RIGHT output of VS1053.
When recording vs1053 redirects signal from LIINE1 to LEFT/RIGHT. SO i can hear the live signal.
Also i see that sensitivity is low on wav file.
When recording i can connect headphones in parallel with vs1053 and my module an i hear the good sensitive signal.

What else should i check?
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Posts: 1848
Joined: Thu 2010-07-15 16:04

Re: vs1053:recording from LiNE1:weak signal

Post by pasi »

Do you have an oscilloscope to determine what is the actual signal level at the LINE1 pin? What is the resulting level in the WAV file?

You're writing 0x5004 to SCI_MODE (LINE1 + ENCODE + SOFTRESET). Are you intentionally using the SDI compatibility mode and not NEWMODE?

Have you tried with the vs1053b patches package or with the small patch provided in the vs1053 datasheet?
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