HD Analysis in SoundEasy

This is the place to post those questions to get your up and running with Soundeasy.
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dcibel
Posts: 39
Joined: Sun Dec 13, 2020 6:39 am

HD Analysis in SoundEasy

Post by dcibel »

It's been a while since I've run HD measurement in SE, just reviewing the process and trying to understand how SoundEasy does things.

The THD/IMD analysis window in SoundEasy doesn't list the left and right channels as reference and input here, but simply left and right. Both channel inputs are displayed at the top time domain, but the bottom frequency domain includes only a single plot.

Is SoundEasy plotting the maximum harmonic product of each channel, an average, or is the reference channel distortion products subtracted from the measurement channel, so that only distortion of the tested device is presented? I am assuming a maximum value displayed here, as the channel labels are no longer reference and input.

It would be clearer as well on this page to keep consistent channel naming, we have Li, Ri, and then In1 and In2 displayed on the same window.

When running a generator sweep, the sweep is very slow, I understand that several measurements are taken at each frequency step to keep noise floor at a minimum? In the MLS system the user has full control over the number of cycles that are averaged, perhaps there could be some user adjustment made here as well to trade noise floor for sweep time?

Another suggestion for the THD?IMD section would be to split the measurement window out like the MLS system, so that the window size can be adjusted. The plot size displayed here is rather small by modern standards. Same suggestion would apply to the other EasyLab meaurement tools other than the MLS/ESS system.
dcibel
Posts: 39
Joined: Sun Dec 13, 2020 6:39 am

Re: HD Analysis in SoundEasy

Post by dcibel »

Played a little with the THD/IMD analysis tool today. As far as I can tell, this tool only produces a distortion analysis of the left channel input, and the right channel, while displayed in the time domain view, is unused.

This is very counter-intuitive operation if this is the case, as elsewhere in the program the left channel is the reference input, and the measurement input such as the microphone is connected to the right channel. Here, to complete distortion analysis, you have to disconnect the reference channel and move the mic over to the left channel. The fact that the right channel is displayed at all here is confusing.

Does it not make sense to use the right channel for THD measurement, and provide some option to subtract left channel HD result from the right channel to try and remove distortion components from the amplifier chain?

The flashing display of harmonic values while the analysis is running should be corrected as well, the values can be updated without flashing like that.
dcibel
Posts: 39
Joined: Sun Dec 13, 2020 6:39 am

Re: HD Analysis in SoundEasy

Post by dcibel »

Same complaint on the Non-Coherence analyzer, reference and mic input are backwards compared to the MLS system. Reference here is the right channel, not the left.
meloV8
Posts: 35
Joined: Thu Dec 03, 2020 10:45 am
Location: Poland

Re: HD Analysis in SoundEasy

Post by meloV8 »

In my opinion, this probes measurement scheme is a bit outdated and not very user-friendly. This disconnection and switching of wires is an unnecessary complication. SoundEasy manual, already on the first pages, should contain a diagram of a simple measurement JIG, something like that from ARTA or other similar measurement systems. That's why, from the very beginning of SE's use, I've been using the ARTA JIG, which significantly speeds up the whole measurement process, and it's elegant without a dozen wires, which have to be constantly switched. For THD measurements and more, as you have noticed, the system requires the reference channel to be reversed. I do not know why it is so mixed up?
I consider the SoundEasy Jig with its mode switches to be absolutely essential and a great improvement of the measurement process.
Maybe in V27 version it is worth to describe the construction of such a JIG based on the ARTA JIG, in which you can also add a capacitor for ribbon drivers measurements.
Of course, it would be advisable to introduce a fixed measurement channel and reference channel for all measurements, or to add the option of inverting the reference channel with the measurement channel in preference.

http://www.artalabs.hr/AppNotes/AN1-Mea ... ev2Eng.pdf ARTA JIG BOX
dcibel
Posts: 39
Joined: Sun Dec 13, 2020 6:39 am

Re: HD Analysis in SoundEasy

Post by dcibel »

In the manual, at the very least the reference and measurement input channels should be labelled on the diagrams in chapter 16, and the software MUST be consistent of which channel is the reference channel in all measurements...

The ARTA jig is very similar to what can be used with SoundEasy, with a couple exceptions.

ARTA appears to have a bit different method for calibration, so you will see the calibration switch on the ARTA jig simply disconnects the load, where the calibration switch on my SE jig will relocate the measurement probe to the other side of the resistor so that both L and R channels probe the same point.

The ARTA jig has some optional components, the zener diodes are generally not needed unless you're prone to doing silly things with the volume knobs.

Back in the day it was called a Wallin jig. I still have the old Wallin jig documentation somewhere around here if you want.
meloV8
Posts: 35
Joined: Thu Dec 03, 2020 10:45 am
Location: Poland

Re: HD Analysis in SoundEasy

Post by meloV8 »

Wallin JIG was designed to work with Speaker Workshop. I do not use this program. It is very outdated, there are problems with the sound card, but it has its old followers. Its capabilities are smaller than other known solutions, especially SE.

The current version of ARTA JIG is just different with this speaker disconnection during calibration. The previous one did not do it. Both versions I used and still use with SE without problems, without any modifications to the JIG.
dcibel
Posts: 39
Joined: Sun Dec 13, 2020 6:39 am

Re: HD Analysis in SoundEasy

Post by dcibel »

The main difference with the ARTA connections is that the right channel is always reference input for ARTA.
meloV8
Posts: 35
Joined: Thu Dec 03, 2020 10:45 am
Location: Poland

Re: HD Analysis in SoundEasy

Post by meloV8 »

Yes, but it is not a problem. Just to work with the SE, I'm switching channels, but to measure THD, you have to change them again. In ARTA you can change the reference channel in the settings.
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