V-NAM-MB

What it is

V-NAM-MB is a Fwuzeem Audio multiband Neural Amp Modeler host. It splits mono or stereo audio into 3, 4, or 5 bands, runs an independent .nam slot on each active band, applies a per-band exponent gain, sums the bands, and can then run a full-range Master NAM on the sum. It provides zero-latency LR4 IIR crossovers or a 256-sample linear-phase FIR crossover, plus the V-NAM global staging, rate, stereo, mix, and engine controls.

Controls & parameters

Global controls

Band layout and crossovers

LR4 uses Linkwitz-Riley IIR crossover filters and reports zero crossover latency. Linear Phase uses a 513-tap parallel FIR bank, with 256 samples of crossover latency and equal-delay band paths for perfect reconstruction.

Per-band controls

There are five possible band slots: Lo, MidLo, Mid, MidHi, and Hi. Each slot has the following parameters; only slots included by Bands are active.

Master NAM controls

Editor detail levels

The editor has Simple, Standard, and Full detail levels. The selected level is stored as the guiDetail state property; its default is 1 (Standard). Simple shows the active band columns, per-band model/gain/bypass controls, crossover frequency controls, Bands, Wet/Dry, and Bypass. Standard adds global Input Shift, Output Shift, Link Shifts, Crossover type, and the information strip. Full adds Retain Sample Rate, Oversample, Stereo Mode, Engine Mode, Precision, and the Master NAM strip. Input Gain is shown only when Link Shifts is on and the detail level is Standard or Full, although its parameter remains active and automatable at every level. The editor’s rotary controls use the house range pi*0.82 to pi*2.18 with a stop at each end.

The shift and gain law

The global shifts, Input Gain, every Band Gain, and Master NAM Gain use literal IEEE-754 exponent shifts rather than ordinary dB scaling. Within the normal finite float range, a +1 shift multiplies each nonzero sample by 2 exactly; a -1 shift divides it by 2 exactly. One shift is 6.0206 dB, and every range above is 20 doublings or halvings. A +1 band gain followed by a -1 band gain returns that band staging ratio to unity. Zero and non-finite samples are skipped; extreme values are clamped by the float implementation, and denormals can flush to zero. Parameter changes are not smoothed in the exponent-shift DSP.

Workflow / how to use it

1. Insert V-NAM-MB on a mono or stereo track. The input and output layouts must match.
2. Set Bands to 3, 4, or 5. The editor shows only the active band columns and the crossover controls needed for that count.
3. Choose LR4 for the zero-latency IIR crossover, or Linear Phase when phase-aligned FIR bands and the additional 256-sample crossover latency are preferred. Set the visible crossover frequencies within their parameter ranges.
4. In each active band, use LOAD to select a .nam capture. After a model is loaded, the previous and next buttons cycle through sorted sibling .nam files for that band. Use CLR to remove a band model. A band without a model passes its crossover output through, but its band gain still applies.
5. Set each Band Gain as a number of doublings or halvings. Use Band Bypass when the crossover band should remain present without its NAM stage.
6. In the Full editor tier, optionally load a Master NAM and enable it. The master runs on the summed signal after the band engines. Use Master NAM Gain to stage that final model.
7. Set the global Input Shift, Input Gain, and Output Shift around the complete multiband chain. Choose L/R or M/S, and choose Retain Sample Rate, Oversample, and Live or Render as required.
8. Use Wet/Dry or Bypass to compare against the latency-aligned input. Save the plugin state after loading models so the existing file paths are included.

Use cases

• Full-range amp + IR split: Put different .nam captures on low, mid, and high bands, then use a full-range Master NAM for final amp or cabinet-style glue where that behavior is represented by a capture. V-NAM-MB loads .nam captures; it is not a direct IR-file loader.
• Bass, mid, and treble processing: Use the 3-band layout to give low, mid, and high material separate captures and exact band gains. A +1 or -1 Band Gain is one exact doubling or halving, so the trims can be reasoned about as ratios rather than approximate dB values.
• Parallel band blending: Load models only where they are useful, bypass individual NAM stages, and use each Band Gain to bring a processed band up or down before the bands are summed.
• Master-glue NAM: Leave the band models focused on frequency-specific work, then enable a full-range Master NAM to apply one final capture to the complete sum. Keep Master NAM Gain at 0 for neutral staging, or use whole shifts for deliberate final doubling/halving.
• M/S multiband work: On a true stereo source, choose M/S to split the stereo signal into Mid and Side lanes before the crossover and restore L/R after the master stage.

Specs & requirements

• Brand: Fwuzeem Audio; manufacturer code Fwzm.
• Formats: AU and VST3.
• Audio I/O: Mono or stereo input/output, with matching layouts. Each active band and the optional master use independent per-channel NAM state. No MIDI processing is enabled.
• Sample rates: No fixed sample-rate list is declared by the plugin. A valid model’s native rate is used for Retain Sample Rate and as the base for 2x/4x modes; an invalid or missing model rate falls back to the host rate.
• Latency: LR4 contributes 0 crossover samples. Linear Phase contributes 256 samples from its 513-tap FIR bank. The reported total is the maximum of active-band crossover plus band-resampler latency, plus the serial Master NAM resampler latency. Resampler contributions vary with the host/native/render-rate relationship.
• Dry path: Bypass and Wet/Dry use a global dry ring whose delay request is clamped to 65,535 samples by the 65,536-sample ring. Reported latency above that ceiling cannot be fully aligned.
• Precision: The processor accepts FP32 and FP64 host callbacks. The Precision parameter is not a DSP switch.
• State: Parameters, per-band model paths, and the Master NAM path are stored as APVTS XML state. The plugin exposes one host program and does not implement preset programs.
• Platform: Workspace audio-toolbox build guidance targets macOS 10.15 or later.

Notes / caveats

• Precision is display-only. Host callback precision determines the callback; selecting FP64 does not force the host to use the double path.
• The Wet/Dry parameter supports 0.1 percent steps, while the current rotary editor displays a rounded whole percent.
• Link Shifts is editor-only. When the editor is open and Link Shifts is on, its slider callbacks can mirror a host-driven shift to the sibling parameter. For editor-independent automation or offline rendering, set Input Shift and Output Shift explicitly if an inverse pair is required.
• Oversample is a creative model-rate control. With Retain Sample Rate off, Off feeds the host rate and 2x/4x feed native-rate multiples. Retain Sample Rate overrides Oversample.
• Master NAM Gain is applied to the summed signal even when Master NAM is disabled or no master model is loaded. Treat it as an always-available master-stage gain, not as a gain that is gated by the enable button.
• A missing or bypassed band NAM is skipped, but the crossover band and its Band Gain remain in the sum. An enabled Master NAM with no loaded model is skipped while Master NAM Gain still applies.
• On state restore, each missing saved .nam path is silently skipped. The slot remains empty and no missing-file alert is shown; load the capture again manually when it is available.
• A failed model load shows a warning and restores the previous file for that slot. Model construction and staged engine swaps are kept off the audio callback.
• In Linear Phase mode, the plugin reports at least the 256-sample FIR crossover latency even when no NAM model is loaded. Loaded band and master resamplers can add more latency.