The decision: audio display vs RF measurement
When you're comparing gear in the oscilloscopes signal spectrum analyzers space, the real fork in the road is signal type. The BDS PP-131 is an audio spectrum analyzer that displays music in real time on a spectrum display. The Agilent N9320B is a professional-grade RF spectrum analyzer for signal measurement. One makes sound visible; the other makes radio frequency measurable. That difference matters more than any feature list.
Quick verdict
Choose the BDS PP-131 if you want an audio visualizer with a compact 2U chassis. Choose the Agilent N9320B if you need to troubleshoot, verify, or teach with an RF analyzer and you're comfortable with a used unit sold as-is and out of calibration.
Price and capability comparison
| Model | Price | Signal focus | Key specs |
|---|---|---|---|
| BDS PP-131 | USD 275.50 | Audio spectrum display | 31-segment green display, DSP control, peak hold and fall time settings |
| Agilent N9320B | USD 1,200.00 | RF measurement | 9 kHz-3 GHz range, -130 dBm displayed average noise level, 10 Hz-1 MHz RBW/VBW |
Where each product wins
BDS PP-131 wins for sound-system installations, home audio, and live performance. It accepts XLR and RCA inputs, lets you adjust display brightness and input level sensitivity, and offers settings like peak hold time and main fall time. It's the lower-priced way to add a visual spectrum to a stereo setup.
Agilent N9320B wins for RF lab work, education, and field troubleshooting. Its frequency range and noise-level spec make it a true measurement instrument for anyone analyzing signals above audio.
Product notes
BDS PP-131 Green Audio Spectrum Analyzer
If your priority is a responsive audio spectrum display, the BDS PP-131 delivers. A high-performance DSP chip drives the 31-segment green display, and the XLR and RCA input/output sockets mean it can sit between a mixer, amplifier, or recorder. The panel has adjustable brightness, input level sensitivity, peak hold time, and main fall time, plus stereo sampling that can show left and right channels at the same time. The standard 2U chassis is compact and stable. The limitation is scope: this isn't an RF analyzer. It won't give you frequency, amplitude, or noise-floor measurements for radio signals. It's an audio visualizer, and its new-open-box condition suggests you should treat it as a display, not a calibrated measurement tool.
Agilent N9320B RF Spectrum Analyzer
The Agilent N9320B is a serious instrument for anyone who measures RF signals between 9 kHz and 3 GHz. With a displayed average noise level of -130 dBm and a resolution bandwidth range of 10 Hz to 1 MHz, it can identify and characterize signals in a way an audio display simply can't. It powers on and functions properly, but it's sold as-is and out of calibration, and no accessories or power cable are included. That's the tradeoff: you'll need to arrange calibration and source your own accessories before relying on it for precise work. If that's acceptable, this is a practical way to get real RF analysis capability in a used instrument.
Final choice by use case
Pick the BDS PP-131 when you want to see audio spectrum activity-home stereo, live sound, or visual installations. Pick the Agilent N9320B when you need to measure RF signals and can work around a used unit's missing accessories and calibration needs.
