Averaging in Smaart v9: RTA Mode vs. Transfer Function (TF) Mode
Averaging in Smaart serves the same core purpose in both modes — to reduce noise, stabilize the display, and reveal the underlying signal trend — but the implementation, options, and practical use differ significantly between Real-Time Analyzer (RTA) mode and Transfer Function (TF) mode.
RTA Mode (Spectrum Measurement)
The RTA is a single-channel magnitude measurement showing the frequency content of an input signal (e.g., pink noise or program material).
Averaging options:
- 1–10 + Infinite: Progressive levels of averaging.
- Settings 1–3: Traditional FIFO (First-In, First-Out) averaging — a fixed number of FFT frames are averaged and the oldest drops off as new ones arrive.
- Settings 4–10: Variable weighted averaging with frequency-dependent time constants (shorter in highs, longer in lows). This gives smoother, more perceptually natural behavior — the trace feels responsive in HF while remaining stable in LF.
- Infinite: Continuously integrates all data since it was started/reset. Ideal for building a highly stable reference with pink noise (run 10–20 seconds).
Typical use:
- Pre-show tuning: Infinite or high averaging for a rock-solid pink noise trace.
- During show: Moderate FIFO (e.g., 2–4 seconds) or weighted setting around 6 to see mix balance without chasing transients.
Transfer Function Mode
The TF is a dual-channel measurement comparing output to input (magnitude and phase). It inherently rejects uncorrelated noise through coherent averaging.
Averaging options:
- Time-based: Specified in seconds (e.g., 0.25 s, 1 s, 4 s, up to 64 s) or as a number of FFT frames (1–1024).
- Coherent averaging: Only energy correlated between reference and measurement channels contributes to the average. Random noise and room reverberation average toward zero over time.
- No FIFO or variable weighted modes — it’s always exponential/coherent averaging.
Typical use:
- System alignment: Start with shorter averages (e.g., 1–4 seconds) for quick feedback while adjusting delays/EQ.
- Final verification: Increase to 16–64 seconds for maximum coherence and noise rejection, revealing the true direct system response.
Key difference: RTA averaging smooths the spectrum display over time; TF averaging actively improves measurement quality by extracting the coherent signal from noise. More TF averaging = higher coherence values and cleaner traces.
In short:
Use RTA averaging to stabilize what you see; use TF averaging to improve what you measure. Both are essential, but they work in fundamentally different ways.
Smaart is excellent on its own, but most users find they get much more out of it after some structured training. That’s where our seminars come in. At TZ Audio we run practical seminars, both online and in-venue. We offer seminar-only or full “all you need packages” including software & hardware. It’s simply the fastest way to become comfortable and confident with the measuring a sound system.
If you’re in Norway, Sweden, Denmark or Iceland – or elsewhere – we offer is online seminars and traveling to Norway is a valid option too of course. We’re here if you have any questions about the software or upcoming seminars.
Thanks for reading!