Source: https://guthlabs.ai/docs/instruments/speaker-impedance-load-calculator-series-parallel/

instrument / verified-clean

# Speaker Impedance Load Calculator (Series/Parallel)

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/speaker-impedance-load-calculator-series-parallel/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/speaker-impedance-load-calculator-series-parallel/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/speaker-impedance-load-calculator-series-parallel/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/speaker-impedance-load-calculator-series-parallel/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Audio, Music, Photography & Color

**Tranche**: tranche-2

**Evidence ID**: t2-025

**Ledger rows**: 1

No ledger note is attached.

## Review findings

Core series and parallel impedance formulas are standard under the stated nominal scalar model. Verdict is NEEDS_REVIEW because the claimed safe-amp-loading warning has no defined formula or required amplifier input, and the supported topology scope is ambiguous.

### Formula and scope findings

- The series formula Ztot=ΣZi is correct for speakers modeled as scalar nominal impedances connected in series.

- The parallel formula 1/Ztot=Σ(1/Zi) is correct for nonzero impedances expressed in consistent units.

- No formula, required input, or decision rule is provided for the claimed 'safe amp loading' or 'min amp rating warning' output.

- The wiring-topology input is ambiguous: the specification does not state whether only all-series or all-parallel wiring is supported, or whether nested mixed series/parallel networks must be accepted.

- Real speaker impedance is frequency-dependent and may be complex; the scalar nominal-impedance formula is only a nominal model, as stated by the honest label.

### Unit assumptions

- Every impedance must be converted to the same unit before arithmetic; test calculations use ohms.

- Impedances are treated as positive scalar nominal values, not frequency-dependent complex impedance curves.

- For parallel wiring, every Zi must be nonzero; a zero-ohm branch causes division by zero and represents an invalid or short-circuit-like load in this model.

- The amp-loading warning cannot be evaluated unless the amplifier's minimum permissible load and a defined warning criterion are supplied.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

A parallel input containing a zero-ohm speaker reaches 1/0 and must be rejected, but the specification does not state an input-validation rule. The minimum amplifier rating warning is also not computable because no amplifier rating or safe-loading threshold is supplied.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "wiring_topology": "series",
    "speaker_impedances": [
      {
        "value": 8,
        "unit": "ohm"
      },
      {
        "value": 8,
        "unit": "ohm"
      },
      {
        "value": 4,
        "unit": "ohm"
      }
    ]
  },
  "expected_outputs": {
    "total_load_ohms": 20,
    "min_amp_rating_warning": "UNDEFINED: no amplifier minimum-load/rating input or warning criterion"
  },
  "working": "Series: Ztot = 8 ohm + 8 ohm + 4 ohm = 16 ohm + 4 ohm = 20 ohm. The amp warning cannot be computed because no amplifier constraint is provided."
}
````

## Related workflows

[Audio Engineer's Rackamp load](<https://guthlabs.ai/docs/instrument-workflows/audio-rack/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche2/tranche2-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`