Difference between revisions of "THD Sweep Measurement"
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Revision as of 15:19, 15 April 2026
THD SWEEP MEASUREMENT - USER GUIDE
Master the art of measuring Total Harmonic Distortion with style
| 🎵 THD SWEEP MEASUREMENT |
| Professional Acoustic Testing Made Simple |
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Install
Dowload THD measurement :
THD sweep measurement April 2026
Install model
Put the model folder : "THD computation" on model database of NVgate. (By default : C:\OROS\NVGate data\Workbook Library\User\ )
⚡ QUICK START - 30 SECONDS
| STEP | ACTION |
| 1️⃣ Launch | Launch NVgate in connected mode and load the THD computation model Double-click THD_Sweep_Measurement.exe
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| 2️⃣ Connect | Put the sweep sine on channel 4️⃣ ; put the response on channel 1️⃣ |
| 3️⃣ Start | Start the THD_Sweep_Measurement.exe and Click green ▶ START button
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| 4️⃣ Monitor | Watch 4 metrics update live , THD and frequency will also be injected on channels DC simulated of NVgate |
| 5️⃣ Stop | Click red ■ STOP button
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✅ That's it! Your first THD measurement is complete. You're now a certified acoustic engineer. (Not really, but it feels good.)
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📊 Four Metric Cards
The heart of the interface. These four numbers tell the whole story:
| 📈 THD (dB) |
📊 THD (%) |
📡 Frequency |
⚡ Fundamental |
| Harmonic distortion (log scale) | Harmonic distortion (%) | Current sweep point | Signal strength |
| +5.42 dB | 58.294 % | 1234.56 Hz | 5.0e-01 V |
🎯 UNDERSTANDING YOUR RESULTS
THD (%) - The Easy Number
What is it? Percentage of unwanted harmonics in your signal.
Think of it this way:
- THD 5% = 95% pure signal, 5% noise
- THD 20% = 80% pure signal, 20% noise
The Quality Scale:
| 🌟 1% - 5% | Excellent - Professional grade equipment |
| ✅ 5% - 15% | Good - Solid speaker performance |
| ⚠️ 15% - 30% | Acceptable - Consumer level equipment |
| ❌ > 30% | Poor - Time for an upgrade 🛠️ |
THD (dB) - The Technical Number
Same measurement as THD (%) but in decibels (logarithmic scale).
Quick Conversion Chart:
| THD % | THD dB | Quality |
| 1% | -40 dB | 🌟 Perfect |
| 3% | -30 dB | ✅ Great |
| 10% | -20 dB | ✅ Good |
| 30% | -10 dB | ⚠️ Poor |
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⚙️ CONFIGURATION
When Do I Need to Change This?
Honest answer: Almost never.
The default settings work for 95% of users. Only change if your NVGate project has:
- Different window names
- Different marker numbers
- Different DC input addresses
If you're not sure → Don't change anything. It works. Trust it.
How to Access Configuration
Click on ▶ Configuration (section expands)
Important Settings
| Setting | Default | When to Change |
| Window (sweep) | Window2 | Your sweep FFT has different name |
| Window (response) | Window1 | Your response FFT has different name |
| Number of harmonics | 9 | 5 (faster), 15 (more detailed) |
How to Apply Changes
- Modify field value
- Click Apply Configuration
- Log displays "Configuration applied" ✓
- Done!
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🔧 TROUBLESHOOTING
Issue 1: NVGate Shows "Disconnected"
What it means: Application can't reach NVGate
Solutions (in order):
- Is NVGate actually open? Check your screen.
- Restart NVGate
- Restart the THD application
- Check Windows firewall allows localhost connections
- Call your IT department and cry
Reality check: 99% of the time NVGate just wasn't open. No shame, happens to everyone.
Issue 2: Measurement Won't Start
What it means: Something blocking the measurement
Solutions:
- Click Run Diagnostic - it will tell you exactly what's wrong
- Common causes:
- No sweep configured in NVGate
- Markers not properly created
- Wrong window names in configuration
The diagnostic is your friend. Use it!
Issue 3: THD Values Show "--.-" (dashes)
What it means: No data is being read from harmonics
Check these:
- Are FFT traces actually visible in NVGate? (Most common issue)
- Is the sweep running?
- Is there audio output to your speaker?
- Are markers properly set up?
Fix one of these and you're golden!
Issue 4: STOP Button Doesn't Work
What it means: Measurement is shutting down but taking its time
Solution: Wait 5 seconds. Seriously. The app is cleaning up.
If it still doesn't respond after 30 seconds:
- Close the window
- Restart the application
- Continue with life
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💡 PRO TIPS
| Tip 1: Start Simple
Always use default settings first. Change things later if needed. Tip 2: Read the Log The log console tells you everything. It's your best friend. Tip 3: Use Diagnostic When something's wrong, click "Run Diagnostic". It's like magic. Tip 4: Multiple Measurements One measurement is interesting. Five measurements is scientific. Tip 5: Document Results Take a screenshot or copy the final THD values. You'll forget otherwise. |
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❓ FREQUENTLY ASKED QUESTIONS
Q: Is THD 5% good?
A: For a speaker? Excellent! You can be proud of that equipment. 🎉
Q: Why does THD change with frequency?
A: Because speakers aren't perfect at all frequencies. Some frequencies cause more distortion than others. That's physics being weird.
Q: Can I use this on any speaker?
A: Yes! Desktop speakers, studio monitors, subwoofers, car speakers - if it's connected to NVGate, we can measure it.
Q: How many times should I measure?
A: Once for curiosity. Three times for reliability. Ten times if you're publishing a paper.
Q: Can I export the results?
A: Yes! Copy text from the log console and paste into Excel, Word, or wherever you need it.
Q: What if my project has different settings?
A: Use the Configuration panel to adjust. It's literally made for this.
Q: Does this work over WiFi?
A: No. It only works locally (same computer or local network). WiFi would add too much latency.
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📞 BEFORE YOU CONTACT SUPPORT
Gather this information:
- Screenshot of the error message
- Last 5 lines of the log console
- Your NVGate window names
- Steps you took before the error
This helps us help you faster! 🚀
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| You're Ready! |
| Go measure some THD and make your speakers proud 🎵 |