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About WASAPI
- WASAPI (Windows Audio Session API) will be available on Windows 7 from Windows Vista SP1 or later. (It is displayed in the list of drivers)
As with ASIO you can expect input and output of the correct data, but it seems that the load is slightly lighter than ASIO in general because it is the function of the OS itself, especially USB It may be good for the device.
However, please be aware that there are quite a few drivers with bugs in practice, as the driver side is still dealing with the same problem, and the corresponding format tends to be small.
For example, even if you pause, you will notice that the sound continues to be output (repeated buffers for the buffer at the stopped position), all formats can not be used unless it is in the timer drive mode, or once it is initialized As long as you do not play or record, do not do anything and close it There are various kinds of Windows death and so on.
Some things could be avoided by some means, but unfortunately those that could not be avoided (those that do not do the first pose etc) are left unchanged.
If the same phenomenon appears in other WASAPI compatible software, it will be a driver bug.
Speeding up display
- Increasing the speed of the
- display means that even if you set down the display interval to lower the CPU usage rate and use it, the CPU usage rate will be lower, so it has its own meaning.
In particular, when using it simultaneously with the sister software WaveGene, we recommend that you lower the CPU usage sufficiently to prevent sound skipping etc. - Since the CPU has recently become faster, there is not much problem, but in order to speed up the calculation itself, there will be only about a decrease in the number of FFT sample data.
However, the display may be considerably faster depending on the setting as below.
1. Change to a high-speed display card if desktop type.
(There seems to be some slow on integrated graphics of integrated chipset.)
2. Decrease the display size of WaveSpectra.
3. Take patience of somewhat flickering and select flickering drawing method.
* Draw "peak only" in Spectrum display " Check it, it may be good as the apparent flicker decreases ...
It seems that it may be affected by the use environment of Windows memory.
(The speed may be different immediately after startup and after using various applications.)
Depending on the display card, it seems that WaveSpectra itself is affected by the difference in display position on the screen even though the window size is the same.
* In fact, a considerable part of the display update time is taken at the time of the screen display rather than the FFT calculation, and the display capability of the display card is working well.
(It seems that the lowering of the drawing speed when making it on a large screen such as full screen display is quite different depending on the display card. It may not decrease much)
Tip:
If you press the Shift key and the Ctrl key at the same time during operation, drawing of the waveform stops during that time, and only FFT and internal processing will be done.
Therefore, by comparing the value of fps at that time with fps at the time of normal drawing, it is possible to estimate the time used for drawing.
The value of fps at this time is very large depending on high speed PC and conditions, and may exceed 999.
In that case, if the uppermost digit is 9 or more, A, B, C, D .... It becomes alphabetic display like hexadecimal.
For example, if it is A23, decimal number is 1023, if D45 If it is 1345 ...., Z 67 it is 3567.
(Actually it will be Z or more in ASCII code order) - Specific drawing method setting method
Once you set the pause time of the display interval to 0 (CPU utilization will be 100% on a single CPU), set the time to maximize fps display and restore the pause period.
Since it has an automatic setting function, it will be convenient to use this function.
Wave - Drawing method and Auto setting
Spectrum - Drawing Method and Auto Configuration Other - display interval and Timer / Hibernation Resolution
About split bar
- By dragging the split bar in the center of the Wave / Spectrum display area you can change the ratio of the two areas.
You can also eliminate one display area.
*Although we did not explain so far in particular, the size of the main window can be freely changed (^ ^;
About sampling frequency
- The sampling frequency corresponds to 100 Hz to 10 MHz.
Internally there is no particular limitation, so it is a limitation only on the display of the scale of the graph.
When playing, it corresponds to an arbitrary frequency.
Outside the range that can be reproduced is simply for analysis.
Even if the sound device does not support it, normal playback is not possible, but you can analyze it using analysis mode analysis position fine designation function.
Even during recording, you can freely set it by writing the numerical value directly, in addition to the frequency set in the setting list box.
However, depending on the device / driver of course whether or not it can be actually recorded.
- From time to time, what is the maximum value of the spectrum display 0 dB or the scale of the waveform display? I am asked the question, but this is the numerical value of PCM Wave format data.
Since the standard CD format is 44.1 kHz sampling 16 bits, the sample data is an integer value of 16 bits-32768 to 32767 It is a value in the range of.
Wave waveform display scales 10000, 15000, 30000 etc. are the values ??themselves.
For the spectrum 0 dB, its maximum value 32768 is 0 dB.
Therefore, since normally recorded sound is usually smaller than this, all the data will be negative like - XX dB.
For formats other than 16 bit please refer to the bottom.
About 8 bit data
- When the data is 8 bit, calculate & amp; display by treating the value of -128 ~ 127 by 256, treat it like 16 bit data.
Therefore, the display of amplitude of Wave is also displayed as it is with 256 times multiplied display, so the display of scale etc. Please note that it is not 128 maximum.
In addition, Spectrum is shifted up by 256 times (about 48 dB) and displayed.
About 24 bit, 32 bit Wave format
- Supported formats are the following three types.
1. 24 bit int (3 bytes / sample)
2. 32 bit int (4 bytes / sample)
3. 32 bit normalized float (absolute value less than or equal to 1.0) IEEE_FLOAT (4 bytes / sample)
Also at this time, Wave on the main window: A character 'F' is added before the bit number, and "F 32 bit" It will be displayed.)
Also, for internal compatibility and readability, all internal processing is done after conversion to floating-point values ??of integer part 16 bits (-32768 to 32767) and fraction part 8 bits (or 16 bits).
Therefore, decimal part is added for waveform leadout etc.
About internal calculation accuracy
- All real arithmetic operations such as FFT are double (64 bit floating point) I am doing it.
However, the parts that can be done with integers are each optimal integer.
Setting dialog
- If the setting dialog is already open and it is hidden under the other window (maximizing the main window etc), set button
, the dialog will appear in the front.
About customizing display color set
- Customization by dialog etc. can not be done, but still it is You can customize WS.INI to an arbitrary display color by directly editing it with an editor.
Windows color notation (hexadecimal), but I think that you can understand because you added a comment easily.
About speed in Lissajous display
- In order to display Lissajous's display smoothly, you need 30 to 40 fps Although it seems to need the display speed above, it seems that even when it is too fast it sometimes disappears with indications becoming ugly.
In such a case, if you set the display interval appropriately and slow down the speed, it will be displayed cleanly.
Therefore, in order to prevent the FFT calculation from being canceled too fast, such as when minimizing the Spectrum window, the display pause time is automatically set internally (5) automatically .
About the number of sample data of FFT (and attention when measuring with sweep signal)
- Although it tends to increase the number of sample data easily and freely in order to raise the frequency resolution, a little caution is needed about this.
In order to obtain the correct value by FFT, it is necessary that the signal is constant and does not change for the time corresponding to the number of sample data.
For example, in the case of 44,100 Hz sampling 65,536 points FFT, the resolution is It is 0.67 Hz at 44100/65536, but at that time, its reciprocal It is necessary that the signal is constant and does not change for 65536/44100 = 1.49 seconds.
If it is a changing signal, it is generally measured less than its original value.
Therefore, in the case of a changing signal such as music, this time also needs to be considered.
In this software, the initial value of the number of sample data is set to 4096 because it is okay if it can see change of about 0.1 second in the CD format.
4096/44100 = 93 ms - When using frequency sweep signal in conjunction with the sister software WaveGene to measure the frequency response by peak hold, please pay attention to the sweep speed.
From WaveGene V 1.40, it is now possible to easily measure accurate frequency characteristics using a cyclic sweep, so we recommend using this.
For details, please refer to measurement of frequency characteristics.
Frequency resolution of FFT
- Sometimes I think that when comparing the noise floor with a spectrum graph, it is necessary to match the frequency resolution in FFT.
The frequency resolution of the FFT is the sampling frequency / Number of FFT samples, for example
For 48000 Hz sampling 4096 points FFT, the resolution is It becomes 48000/4096 = 11.71875 Hz.
(Frequency resolution can be checked easily by keeping Spectrum's comment line)
If this is not adjusted, the position of the noise floor will change, so you need to be careful in the comparison.
For example, if you change from 48000 Hz to 96000 Hz sampling, the same conditions as above (the noise floor will not be displayed at the same position) will have to be made unless the number of FFT samples is also changed from 4096 to 8192.
Generally, when the frequency width of the resolution is expanded twice, the noise floor rises by 3 dB, and when it becomes half, it decreases by 3 dB, so 48000 Hz sampling 4096 points FFT If you change to the 65536 point FFT, the noise floor will drop by about 12 dB.
(4096 - & gt; 8192 - & gt; 16384 - & gt; 32768 - & gt; 65536 & 12 dB in 4 steps)
* Even with the same signal, if you increase the number of FFT samples, the noise floor will appear to be lowered so it seems that it seems to be high performance at first glance? (^ ^;
About multi-client support of ASIO driver
- If you use two programs synchronize, use this software for recording and playback, or when you use it together with the sister software WaveGene When you use it, if you use both ASIO drivers of the same device, it is necessary for the driver to support multi-client (and multi stream?).
If it is not compatible, one may become grayed out so that it can not be selected, but even if it can be selected with both, it seems to be usable once it hangs up or ends at a blue screen It seems there are times when you do, please be careful.
About error when using MME driver
- Depending on the embedded audio codec, Wave There seems to be a case that it hangs up with an error when format listing is done with Mapper.
In that case, try not to use that CODEC, or if you can not do that, WS.INI In the [Conditions] section of the "Notepad" " For example,
Use_WF_DIRECT=1
After adding the line of and starting up, WAVE_FORMAT_DIRECT You will be opening a device with a flag, so you may be able to avoid errors, so please try.
(Note that MME can not be used on Windows Me, 98/95, please note that this time it does not work on 95/98 / Me)
About the Wave file information window
- In the Wave file information window, you can see the internal chunk structure if it is a RIFF file in addition to the wave file (PCM) I will. (Chunk viewer function)
However, if you try to open it as is, "If you can not open the file" or Drag & amp; Drop "Extension is not WAV" Although it is rejected, if you hold down the Ctrl key and open it will display a message "This file is not a valid PCM file" but you can force it open and you can see the contents of the chunk.
Note:However, because content analysis is not supported, the description is incorrect.
For details, please refer to Extra applied.
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