Is it possible to fine tuning the pitch / volume of the ADAU1401a?
Hi AID's
One of the customers is developing the ADAU1401a and she wants to control pitch and volume precisely.
she would like to be able to adjust to two decimal places as much as possible to implement the function.
(Assuming that the input signal is 100% frequency, wants to control it like this: 100% -> 102.55%)
In Sigma Studio, the Pitch Shifting and volume controls appear to work only with numbers
I do not think it's supported by blocks, is there any special way?
Thank you
adau1401a
Audio Signal Processors
SigmaDSP Audio Processors
Hello Andrew,
There is a cell that is a VCO. It will vary the pitch with a DC input but I do not know if this kind of accuracy is possible. In the end it is being digitally synthesized to take a certain number of steps from the sine table per sample period and output the new value. So at very close to nyquist it will have only two sample to go up and then down. So the frequency resolution will become very poor at higher frequencies. So the big questions I have is this: What is the range of frequencies that this level of precision is required?
I will have to study this to see if it is possible once I have your answer.
I should also know what is the sampling rate required? Are they flexible with the rates?
I guess I have some more questions. How are they wanting to control the frequency? With a controller or with the AUXADC input?
With an up/down button?
Dave T
Hi Dave
an answer to the question you were wondering above
1. Shifting the desired frequency range
Depending on the situation of six sources, one to five simultaneous playback while trying to shift the frequency and volume.
The frequency you want to control is shifting to about 150% sequentially, with the original sound at 100%.
Ex) 100.00% 100.01% 100.03% 100.06% 100.10% . about 150.00%
(The frequency does not increase linearly but increases exponentially)
* The FFT value of the sound source to be played mainly is attached as the following graph.
Since most of the low-frequency components are strong, think that 150% shifting will not affect the actual sound even if there is some high side loss.
(The frequency component values of the remaining sources are located in the lower frequency region than in the graph)
2. Sampling rate
It uses 48 kHz and is a 16-bit sound source. (Bitrate 768kbps)
* attach the Wave Header value of the original sound.
3. Sampling rate flexibility
This section did not understand exactly what you wanted
4. Frequency control method
The SPI will be used as an interface for controlling the ADAU1401A, and the sound source data will be sent to I2S.
Therefore, the frequency adjustment is to change the output frequency setting value by transmitting the parameter to SPI.
* Do I need to input the ADC, etc. to the ADAU1401A separately to adjust the frequency?
If you need anything else to adjust the frequency, I would appreciate your advice.
Thank you
Hello Andrew,
Oh!!! Now I understand what they are trying to do! I was interpreting your question that they wanted to change the frequency of an oscillator in the DSP. No,... they want to change the pitch of an audio file! This is a very different question. Sorry, this was my fault for not reading your question carefully enough.
I will look into this and get back to you.
Dave T
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