TAS5751M: TAS5751M - how to set optimal input/output gain settings for optimal performance?

Lauren Mayfield

Part Number: TAS5751M

Hi MPAA team,

I'm posting a question on behalf of my customer. The goal is to operate the audio amp at the optimal area for sound performance.

"We’re using the TAS5751M to drive a 10W speaker (mono).

Currently if the max volume from the digital domain is set to 0db we need the amp master gain to be set to +7dB.

We can reduce the gain from the digital domain and increase the amplifier master gain.

Would that approach yield any benefit?

What would be the optimal input/output gain settings for audio quality performance?"

The end application is a smart mirror.

Thank you for your assistance!
Lauren

over 5 years ago

0 Andy Liu (BMS) over 5 years ago

TI__Guru 52115 points

Hi Lauren,

I will take a look and get back to you.

Andy

0 Lauren Mayfield over 5 years ago in reply to Andy Liu (BMS)

TI__Expert 7180 points

Hi Andy,
Sounds good. Thanks for the help and looking forward to your feedback.

Lauren

0 Andy Liu (BMS) over 5 years ago in reply to Lauren Mayfield

TI__Guru 52115 points

Hi Lauren,

I see your customer mentioned that the max volume from the digital domain is set to 0dB.

Does the volume they were talking about mean the two volume blocks in the TAS5751M below?

Andy

0 Guy Cohen over 5 years ago in reply to Andy Liu (BMS)

Prodigy 40 points

Hi Andy (Thank you for posting Lauren),

What I meant is that when we feed the amplifier with max amplitude on the I2S line, we have the Master volume in the amp set to +7dB.

Currently the amplification registers are set to:

Name	Register Address	Register Value	Value Description
Channel 1 Volume	0x08	0x00C0	0 dB
Channel 2 Volume	0x09	0x00C0	0 dB
Master Volume	0x07	0x0088	7 dB
Pre Scale	0x57	0x00020000	0 dB
Post Scale	0x56	0x00721482	-1 dB

my question is mainly related to the best area of operation for the amp.

for example, would there be any benefit to set the max volume on the I2S line to -3dB and set the Master volume gain to +10dB?

Thank you.

0 Andy Liu (BMS) over 5 years ago in reply to Guy Cohen

TI__Guru 52115 points

Hi Guy,

Does the max amplitude on the I2S line you mentioned mean 0dBFS input? If not, what kind of signal in terms of dBFS appear on the I2S line?

Andy

0 Guy Cohen over 5 years ago in reply to Andy Liu (BMS)

Prodigy 40 points

Yes, max input volume meant - 0dBFS on I2S line.

Thanks

0 Andy Liu (BMS) over 5 years ago in reply to Guy Cohen

TI__Guru 52115 points

Hi Guy,

Could you share with me your .ppc3 file, which can be loaded by PPC3 GUI? I would like to check your other tuning settings.

Andy

0 Guy Cohen over 5 years ago in reply to Andy Liu (BMS)

Prodigy 40 points

Config.zip

0 Andy Liu (BMS) over 5 years ago in reply to Guy Cohen

TI__Guru 52115 points

Hi Guy,

Thanks. Let me take a look.

Andy

0 Andy Liu (BMS) over 5 years ago in reply to Andy Liu (BMS)

TI__Guru 52115 points

Hi Guy,

Sorry for my late response. I have run out of TAS5751MEVM and just received one today.

In your case, you will NOT see more benefit if you set the max volume on the I2S line to -3dB and set the Master volume gain to +10dB.

The major reason is that the Full Band AGL is enabled in your tunning file. No matter what the master volume is set to, the max output power will be limited to about 13W. You may wonder why you see about 10W instead. It is because you set the post-scale to -1dB instead of the default 0dB.

Andy

0 Guy Cohen over 5 years ago in reply to Andy Liu (BMS)

Prodigy 40 points

Thank you very much.

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TAS5751M: TAS5751M - how to set optimal input/output gain settings for optimal performance?