Extreme pure sine (0.0007% THD+N)

[xstreme]

News...
QUASI PURE SINE

An externally hosted image should be here but it was not working when we last tested it.

 

[scott wurcer]

For best results one should use "prime frequencies" of the FFT size, and no FFT window, of course. This is also intrinsically self-dithering.
No sample value ever occurs twice in the whole sequence (FFT size) but the sequence itself must repeat perfectly (for the non-windowing to work).
This is whole idea and recipe for the construction.

Unfortunately the maths are simple but few get it. A 1kHz sine wave sampled at 96kHz uses only 96 codes of which only 48 are unique. No dither is necessary because the values and time samples are exact since this is a closed numerical exercise.

 

[xstreme]

Unfortunately the maths are simple but few get it. A 1kHz sine wave sampled at 96kHz uses only 96 codes of which only 48 are unique. No dither is necessary because the values and time samples are exact since this is a closed numerical exercise.

96K sine resampled to 44K sine with dither, in this case dither increase the codes ?

 

[xstreme]

Don't Get Lost in the Noise Floor PDF

http://www.analog.com/media/en/training-seminars/tutorials/MT-003.pdf

An externally hosted image should be here but it was not working when we last tested it.

 

[HpW]

Don't Get Lost in the Noise Floor[/IMG]

You means to analyze something like this...

Hp

 

[xstreme]

I have written a custom macro to explore the noise floor at various frequencies,
This macro creates a auto-text txt file which contains all the results.
see this video on youtube
https://youtu.be/XmQ9iyqh4XA

An externally hosted image should be here but it was not working when we last tested it.

 

[xstreme]

This is the video of noise floor at 20 KHz - 90 Khz range (HD?)
https://youtu.be/faGUJ3XyXNI

 

[JohnPM]

Are you still using un-dithered signals? Really would be so much cleaner if you dithered them.

 

[xstreme]

Arta
(UP) 24bit + Dither
(DOWN) 24bit - Dither

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

 

[JohnPM]

You do need to start with a clean signal of course, I'm afraid dither won't remove your distortion for you. Same signal in ARTA, no dither on top, dithered below.

 

[xstreme]

ah, ok, filtered and this is my max lower floor

An externally hosted image should be here but it was not working when we last tested it.

 

[xstreme]

You means to analyze something like this...

Hp

But your software is a 'real-time' like Spectraplus or is a 'only reading files ?

 

[HpW]

But your software is a 'real-time' like Spectraplus or is a 'only reading files ?

- Sound Card realtime MME, WDM, ASIO Sync I/O, ASIO Multi Client, WASAPI Exclusive Input & Output and also on ASIO 2x..8x speed (channel bundling)

- Analise Wave Files

- Analise Text Files

- Wave Generator with various signals

- Level, Power, Spectrum Density, Fast Freq. Response

http://www.diyaudio.com/forums/vendors-bazaar/157053-ann-hpw-works-v3-0-pc-based-measurement-system.htmlhttp://

Or download PDF and read on or simple download the evaluation SW for the the homepage

Hp

 

[xstreme]

- Sound Card realtime
Hp

i have downloaded your trial software for evalutating my noisefloor ,
I'm probably rusty, but I have not managed to use it and see my noisefloor in realtime in any way

 

[HpW]

I'm probably rusty, but I have not managed to use it and see my noisefloor in realtime in any way

In case of any difficulties please, as usual, contact the given support channel with related information(s)


Hp

 

[deChrLam]

@JohnPM and XSTREME
How did you get ARTA to display a spectrum analysis? I cannot find an option in ARTA to load a wav for spectrum analysis. Did you use a loopback device or similar to play the wav?

Cheers, dechrlam

 

[JohnPM]

I was plotting the output of REW's signal generator over an S/PDIF connection with ASIO drivers (to provide a 24-bit data path).

 

[xstreme]

HpW

I was plotting the output of external signal generator (like Viktors) over an analog connection input with ASIO driver.
My audio chipset is from
1) Generic Laptop with internal Asus Soundcard (16 bit)
2) Generic PC with external RME Audio Soundcard (24 bit)
3) Generic PC with internal Lynx AES16e Soundcard (24 bit)
my low THD soundcard is the AES16e = -140 flat

 

[1audio]

?? The AES16e is digital input only. What are you using to convert Victor's oscillator to digital?

 

[deChrLam]

Thanks for the replies guys. I can playback and record 96/24 over SPDIF bit perfect. I will give it a go and compare the sines here to the rme sine below.

There are some free 0.001 THD+n sines here too:
RME Intelligent Audio Solutions - Audio Test Files