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Messages - FaberAST

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SignalScope X / Welcome to the SignalScope X discussion
« on: January 10, 2018, 03:17:36 PM »
SignalScope X, the successor to SignalScope and SignalScope Pro, includes a free oscilloscope and subscription-based tool sets to meet your more serious needs.

See our note about moving to subscriptions on the blog.

SoundMeter / Re: Calibrate MicW i437L
« on: November 27, 2017, 04:50:01 PM »
Unfortunately, the i437L presents itself as if it were a standard headset jack. This means that apps like SoundMeter cannot automatically distinguish between an i437L and a standard headset jack.

Your approach is correct (i.e. Device Units = FS, Channel Units = Pa, Gain = Mid). We do not know the precise input gain used by MicW when testing the sensitivity of the i437L, but using the Mid gain setting in SoundMeter seems to work well.

It's too bad MicW didn't take advantage of the opportunity to produce a digital microphone that presented itself uniquely to iOS. That would have allowed automatic loading of sensitivity information, similar to what SignalScope does with the Digiducer digital accelerometers.

SignalScope / Re: RTA Averaging
« on: November 16, 2017, 10:05:20 PM »
Yes. With those settings, you'll get the average sound level over 20 seconds in each whole or 1/3 octave band, plus an overall (full bandwidth) average level. You can see the overall level by tapping the graph to turn on the cursor.

SignalScope / Re: RTA Averaging
« on: November 16, 2017, 08:45:38 AM »
Based on your description, I would recommend that you look in the Octave Analyzer options menu and set Level Type to Leq, turn on Auto Stop, and set the duration to 20 seconds.

SignalScope / Re: RTA Averaging
« on: November 07, 2017, 03:39:50 PM »
What would you like to do with averaging?

SignalScope / Re: RTA Averaging
« on: November 01, 2017, 02:46:45 PM »
In SignalScope, you'll see an info button (a little 'i' in a circle) on the right side of the toolbar at the top of the screen. Tap that, and then tap on Help.

SignalScope / Re: RTA Averaging
« on: October 30, 2017, 06:10:15 PM »

The Octave analyzer tool (RTA) supports both exponential (Lp) and linear (Leq) averaging of the signal in each whole or 1/3-octave frequency band. For exponential averaging, Fast, Slow, and Impulse time weightings are supported. For linear averaging, the average level is calculated over the entire duration of the measurement.

SignalScope's built-in documentation includes information on how to access the averaging options.

Let us know if you have more questions.

Electroacoustics Toolbox / Re: Basic setup guide
« on: April 27, 2017, 06:46:29 PM »

If you are trying to perform dual-channel measurements (e.g. frequency or impulse response), I would point you to the tutorial on the blog for reference.
Frequency Response Measurement with Electroacoustics Toolbox 3

Why can't you use the output of the Duet to use the built-in test signals? Perhaps, a more detailed description of what you are trying to do, and how you would like to set it up, would help us zero in on a suitable solution.



Bluetooth mic input is typically sampled at 8 kHz. The weighting filters in the Meter and the bandpass filters in the Octave analyzer are designed to operate at multiples of 44.1 kHz and 48 kHz, which would explain the "Unsupported Sample Rate" message.

It seems that some time ago Apple changed the behavior of Bluetooth audio in iOS (at least in the Measurement Mode that SoundMeter uses). Since SoundMeter requires both input and output from the audio system, Bluetooth won't work unless you are using a Bluetooth headset (or hearing aids, in your case) with both input and output. Unfortunately, if you use a headset for input and output, then the sample rate will be restricted to 8 kHz (for both input and output).

This is a change from how Bluetooth used to work on iOS, when it was possible to use the built-in mic with Bluetooth output.

I wish I had better news.



I'm not aware of any affordable sound level meter software for Windows.

You might consider an iPod touch as a less expensive alternative to the iPhone. The accuracy of your measurements will depend on the quality of your calibration, regardless of which device you use. You can get more reliable measurements with an external measurement microphone, like the MicW i436.


SoundMeter / Re: Using Exteral Microphones and Calibration
« on: January 25, 2016, 10:27:37 AM »
SoundMeter's built-in documentation includes a device input voltage calibration tutorial.

To access the documentation, tap the info button ("i") in the toolbar at the top of the main screen. Then, tap on Help in the Info screen.

Electroacoustics Toolbox / Re: nan dB
« on: October 26, 2015, 08:26:51 PM »
"nan" stands for "not a number" and indicates that some invalid arithmetic operation occurred (like dividing zero by zero).

SignalScope Pro / Re: THD measurement
« on: October 16, 2015, 01:43:00 PM »
Am I correct in assuming that the number of spectral lines is equivalent to the number of bins?
Yes. Each line represents one bin.

SignalScope Pro / Re: THD measurement
« on: August 13, 2015, 10:24:41 AM »
SignalScope Pro's FFT Analyzer tool is capable of computing THD with up to 15 harmonics.
In order to get good results, you'll need to use a test signal that's at a frequency that matches one of the frequency bins in the FFT. This is fairly simple if you use SignalScope Pro's built-in signal generator and use the same audio device for both output and input in your measurements.

IOScope / Re: Feature suggestions
« on: March 16, 2015, 10:26:13 AM »
IOScope 5 added frequency smoothing in 1/6th, 1/12th, and 1/24th octave band resolution. It also added support for loading previously captured measurements for direct comparison with the live curve.

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