Line out, Line in and Headphone connections

Designing hardware that use VLSI Solution's devices as the system controller for the entire design.
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Henrik
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Re: Line out, Line in and Headphone connections

Post by Henrik » Fri 2016-07-29 14:00

Hello!

Maximum gain in AGC is always a compromise between speech volume and background noise: with a moderate maximum gain (e.g. 12 dB -> SCI_AICTRL2 = 4096) there isn't usually too much noise but sound level may be too low. With a higher maximum gain (e.g. 30 dB -> SCI_AICTRL2 = 32768) sound levels are usually high enough but there may be excessive background noise. You must try and find the best compromise for your application.

Also the microphone itself is extremely important: if you can use a directional microphone, it usually gives a much better signal-to-noise ratio, but if you need an omnidirectional microphone then you have to accept that it records also noise from every direction.

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czpzkz
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Re: Line out, Line in and Headphone connections

Post by czpzkz » Sat 2016-09-24 15:28

Hi,

I am making a tiny sound synth module for my wireless midi receiver using vs1053b on real-time midi mode, its work, I use the dragram from MIDI music shield V13 and the value of components for audio output follow the dragram of this post, the sound seem less of treble and lot of bass, any simple way to make it more brighten, I have look througth the menus and found that there are GPIO2 and GPIO3 for configured the EarSpeaker, but don't know how to configured it, currently both pins are low level, please help. Thanks.

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Henrik
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Re: Line out, Line in and Headphone connections

Post by Henrik » Mon 2016-09-26 10:49

Hello,

and welcome to the forum!
czpzkz wrote:I am making a tiny sound synth module for my wireless midi receiver using vs1053b on real-time midi mode, its work, I use the dragram from MIDI music shield V13 and the value of components for audio output follow the dragram of this post, the sound seem less of treble and lot of bass, any simple way to make it more brighten, I have look througth the menus and found that there are GPIO2 and GPIO3 for configured the EarSpeaker, but don't know how to configured it, currently both pins are low level, please help. Thanks.
The frequency response should be very straight (within less than -0.1 dB to +0.1 dB) if you have implemented the line out or earphone out as instructed in Panu's original image. So please first verify your connections. If you still want to adjust, and you have a microcontroller, you can adjust treble and bass using the SCI_BASS SPI register of VS1053. See the Datasheet for details.

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pasi
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Re: Line out, Line in and Headphone connections

Post by pasi » Mon 2016-09-26 13:46

If you are generating or processing the MIDI data yourself, you could adjust the velocity according to the note value to de-emphasize the lower frequencies.
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czpzkz
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Re: Line out, Line in and Headphone connections

Post by czpzkz » Mon 2016-09-26 19:43

:) Hello,

My mcu has only TX pin connect to the vs1053b board, so there is no way to sent command for setting the register inside the chip, anyway I have listen to some video on youtube with vs1053b sound, some instrument sound bright, may be I just listen the piano sound on my board and feel that the sound was dark. So I will let the chip playing my orchestra midi file with 16 channels after I complete the receiving module.

One more question, the "pop sound" is loud while power-up, I try to connect a 10uf condenser on reset pin to ground, the vs1053b start slower than the mpu, but the "pop sound" remain, any "soft start" method to reduce this pop sound? For Hi-Fi system users they are "ultra sensitive" to this pop sound so I have to try my best to reduce it, Thanks.

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Re: Line out, Line in and Headphone connections

Post by pasi » Mon 2016-10-03 11:32

What is your output connection like? Is it like in our example?

The analog outputs of VS10xx are biased to around 1.2V. It means the center value is 1.2V and the output voltage swings above and below that level.

When released from reset, vs10xx first enables analog power. This will cause the LEFT, RIGHT, and GBUF to get internal bias, and also the outputs will slowly start to change.

After a while the analog drivers are enabled, and LEFT, RIGHT and GBUF are actually driven to their state. If you don't send audio data immediately after powerup, lowering the samplerate (write a lower value to AUDATA) will increase the time before drivers are enabled.

A potential way to prevent a pop after power-up is adding a mute circuit to the output. It allows the outputs to bias correctly before allowing the line output to operate.
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sanchoo
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Re: Line out, Line in and Headphone connections

Post by sanchoo » Mon 2017-04-10 14:07

Hello VLSI!

I use two vs1000d modules in my project, and I need to get a mono output consisting of the sounds of both modules.
i trying schematic as below, but received a strong mutual influence between the channels.

Reducing the volume of channel 1 also reduces the volume of channel 2.
Tell me how to solve this problem by minimal means?
Great, great thank`s!!!

U1,U2,U4 - 50-100k
Image

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pasi
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Re: Line out, Line in and Headphone connections

Post by pasi » Mon 2017-04-10 16:40

1. Pin 2 of U1 and U2 should be connected to GND.

2. Resistances and capacitors create a lot of low-pass filters in the chain, so the values should be chosen carefully.

Do you need stereo-to-mono conversion? Do you have control of the files? Could you just encode in mono and use just the LEFT output? (Or add a stereo-to-mono conversion in the firmware.)
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sanchoo
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Re: Line out, Line in and Headphone connections

Post by sanchoo » Mon 2017-04-10 21:13

pasi wrote:1. Pin 2 of U1 and U2 should be connected to GND.

2. Resistances and capacitors create a lot of low-pass filters in the chain, so the values should be chosen carefully.

Do you need stereo-to-mono conversion? Do you have control of the files? Could you just encode in mono and use just the LEFT output? (Or add a stereo-to-mono conversion in the firmware.)
if i connect U1, U2 to GND than situation worsens. Yes i have control under files, and can try use only LEFT ... but why?
thank`s for atantion Pasi.

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pasi
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Re: Line out, Line in and Headphone connections

Post by pasi » Tue 2017-04-11 9:24

sanchoo wrote:Yes i have control under files, and can try use only LEFT ... but why?
If you use only one of the outputs, you don't need the series resistors and can avoid some of the low-pass filter effects.

Also, the LINE outputs already have a DC block, which eliminates the first capacitor.

If you can use the volume control of the modules, then you only need to sum the outputs. But I guess you want a manual balance adjustment?

Unfortunately you'll need a better different person than me to help with the analog design...
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