If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

# TAS5534 Loudness Processing Block Diagram

Other Parts Discussed in Thread: TAS3103A, TAS5538, TAS3103

Hi,

We would like to confirm whether the loudness processing block diagram that is described on page 30 of data sheet is correct or not,
show the block diagrams of TAS5534 data sheet and ALE 5.2 application report as below.
Could you please confirm which expression is correct?

TAS5534 Loudness Processing

ALE 5.2 Loudness Processing

Best Regards,
Kato

• Hi,

Best Regards,
Kato

• Hi, Kato-san,

We will get back to you shortly on this.

-d2

• Hi Don-san,

Best Regards,
Kato

• Hi Kato-san,

The V should not be there. It a mistake. Sorry for the delay to get the answer for you.

reg,

Paul.

• Hi Paul-san,

We could understand that the addition of "V" is not correct.
So, if we remove the addition of "V" about figure 3-11 of data sheet, we believe that the equation of loudness function is as below.

Audio Out = Audio In * V [1 + H(z) * f(v)]

On the other hand, we seem that it is about ALE 5.2 as below.

Audio Out = Audio In * [V + H(z) * f(v)]

Which the equation is correct?

Best Regards,
Kato

• Hi Paul-san,

We found that there is described regarding the loudness compensation block diagram on page 3-25 of TAS3103A data sheet.
If the loudness function of TAS5534 and TAS3103A is same, we believe that the equation of ALE 5.2 and TAS3103A is correct.
Is our understanding correct?
The equation of TAS3103A is as below.

audio out = [audio in * volume_setting] + [audio in * F(s)biquad * f(volume_setting)]

Best Regards,
Kato

• Hi Paul-san,

Best Regards,
Kato

• Hi, Kato-san,

please see attached for loudness description.

0312.Loudness Compensation.docx

reg,

Paul.

• Hi Paul-san,

Thank you for explaining.
We would like to know the meaning of the "Maximum individual* master volume".
Is this the value that multiplied the channel volume by the master volume?
Then, the path that multiplying the "Maximum individual* master volume" is not found.
In addition, the format number of loudness parameters is different on page 30 of TAS5534 data sheet(e.g. offset parameter and log parameter).
Is this a mere typo?
Could you please describe block diagram using a calculating formula?

Best Regards,
Kato

• Hi Paul-san,

Do you have any updates for this issue?

Best Regards,
Kato

• Hello Kato-san:

As explained in this thread: http://e2e.ti.com/support/amplifiers/audio_amplifiers/f/6/p/324345/1185441.aspx#1185441

the "Max Volume" used in the loudness block is derived from the master volume and the individual channel volume multiply with the modulation index limit setting.  The block diagram is too general (high level) to show the max volume in the loudness block.

Best regards,

Tuan

• Hi Tuan-san,

Thank you for explaining.
Since the loudness algorithm of TAS5534 and TAS3103A is same, I believe that the equation and the block diagram of ALE 5.2 and TAS3103A are correct.
The equation of TAS3103A is as below.

audio out = [audio in * volume_setting] + [audio in * F(s)biquad * f(volume_setting)]

Best Regards,
Kato

• Hello Kato-san:

Yes.  But, perhaps I need to ask you a few questions so that we can give a better answer.  Going back and forth with questions may not help the customer resolving their problems.

1.  What does the customer need with loudness parameters?  What is the purpose for this?

2.  Does the customer want to port TAS3103A loudness biquads to TAS5534? Or did they find some differences between the two devices?

3.  Or does the customer want to modify his/her current loudness settings?

Thank you.

Best regards,

Tuan

• Hi Tuan-san,

I am so sorry to have confused you and answer your questions as below.

Q1.
Since a calculating formula was different from the loudness function block diagram of TAS5534 that is described in a data sheet,
I received an inquiry from our customer.
Therefore, our customer would like to know the correct calculating formula and loudness function block diagram.

Q2.
Our customer who asked about difference between the loudness algorithm of TAS5538 and TAS3103 is different from our customer who asked about Q1.
Since I suggested ALE5.2 to our customer, it was asked you a question simply.

Q3.
Our customer will optimize it about it.

Best Regards,
Kato

• Hello Kato-san:

Thank you for your explanation.  I understand now.

Q1 answer - The functional block diagram does not have enough details as in the mathematical expression.  Please use the equation in the data sheet (also same as system specification).  As previously explained, it is also the same as TAS3103A.  Hope this helps.

Best regards,

Tuan

• Hi Tuan-san,