homecrate amp — Neural Amp Modeler + IR Cabinet

homecrate amp is a guitar amp simulation plugin, available as an AUv3 effect extension you can load on any audio track in Homecrate. It uses Neural Amp Modeler (NAM) technology to capture the exact character of real amplifiers, combined with Impulse Response (IR) cabinet simulation, a 5-band EQ, and a built-in room reverb.

🟢 New to amp sims? Skip to Quick Start. You can get a working guitar tone in about 60 seconds.

🔵 Familiar with NAM / Kemper / Quad Cortex? homecrate amp loads standard .nam profile files. The signal path is: stereo in → mono downmix → input gain → NAM DSP → IR convolution → EQ → reverb → output gain → stereo out.

What is NAM?

Neural Amp Modeler is an open-source technology that uses machine learning to capture the behavior of real guitar amplifiers and pedals with high accuracy. A .nam file is a trained model of a specific amp — its distortion character, frequency response, touch sensitivity, and dynamics.

NAM models are widely shared by the guitar community. Thousands of free models are available online for everything from clean Fenders to high-gain Mesa rigs.

Think of a NAM model as a photograph of an amplifier’s sound. Load it and your guitar sounds like it’s going through that amp.

Quick Start

Load homecrate amp as an AUv3 effect plugin on an audio track in Homecrate
Arm the track for monitoring (tap R twice to reach the orange Monitor state) — you should hear your guitar dry
Tap the NAM MODEL filename area to open the model picker
Select a .nam file you’ve downloaded, or tap Browse Files… to import one
Tap the IR CABINET filename area and load an impulse response file
Adjust INPUT and OUTPUT knobs to taste

Your guitar now sounds like the modeled amplifier through the modeled cabinet.

Loading homecrate amp in Homecrate

See Loading & Removing Plugins for the general steps. homecrate amp appears under the Effects tab in the Plugin Browser.

After loading it in a slot, arm the track. Set the track’s input source to your guitar interface input (tap the Input button on the channel strip). Put the track in Monitor mode (orange R button) to hear yourself through the amp sim in real time.

homecrate amp processes audio at 48 kHz (the AUv3 session sample rate when an interface is connected). The NAM DSP block runs on the real-time audio thread via a std::mutex::try_lock pattern — if a model is being loaded on the background queue, the render pass runs through without processing rather than blocking. This means the first few milliseconds after loading a model may pass through dry, then the amp sound kicks in.

The Interface

[SCREENSHOT: Full homecrate amp interface — amp head section, cabinet section, EQ, reverb, presets]

The interface scrolls vertically and is divided into four sections:

Amp Head — NAM model selection, Input and Output gain knobs
IR Cabinet — Impulse response selection and bypass toggle
FX Strip — 5-band EQ and Room reverb
Presets — saved preset pills

Amp Head Section

[SCREENSHOT: Amp Head section]

Status Dot

The small circle to the left of “AMP HEAD”:

🟢 Green — a NAM model is loaded and processing
🔴 Red — no model loaded (signal passes through with gain only)
🟡 Yellow — the previously used model file was not found (e.g. after restoring a backup)

NAM Model

Tap the filename area to open the model picker sheet. This shows:

Models previously imported into homecrate amp’s local library
A Browse Files… option to import a new .nam file from anywhere on your device

[SCREENSHOT: NAM model picker sheet]

When a model loads successfully, the architecture type (e.g. “LSTM”, “WaveNet”, “ConvNet”) appears as a badge, along with the model’s expected sample rate and loudness metadata.

The architecture badge comes from the .nam JSON header (NAMModelInfo). LSTM models are the most common and are optimized for real-time use on iOS. WaveNet models are heavier; on older devices they may cause CPU spikes at low buffer sizes — increase the IO buffer to 10 ms if you hear dropouts. See Audio Settings & Buffer Size.

The 📁 folder icon (top-right of the model row) opens a system file picker directly, bypassing the local library list — useful when importing a model for the first time.

Input Gain Knob

Controls the signal level into the NAM model. Range: 0.0–4.0× (linear gain).

This knob uses a Fender-style taper: the first 75% of the knob rotation covers the 0–1.0× range (clean/unity), and the last 25% covers 1.0–4.0× (overdrive territory). This gives fine control in the clean range and a distinct “pushed” zone at the top.

[SCREENSHOT: Input knob at different positions — clean range vs. overdrive range]

When Input exceeds 1.0×, the grille cloth overlay on the background image fades out progressively, giving a visual indication of how hard the amp is being driven.

Start with INPUT at the 9 o’clock position (approximately 0.5×) and adjust by ear. Higher input = more saturation and compression. Lower input = cleaner, more dynamic response.

Output Gain Knob

Controls the output level after the NAM model and IR. Range: 0.0–4.0×. This is a post-processing volume control — it does not affect the tone or saturation character.

IR Cabinet Section

[SCREENSHOT: IR Cabinet section]

The IR Cabinet simulates a guitar speaker cabinet by convolving your signal with an Impulse Response — a recording of how that cabinet responds to an impulse signal.

Status Dot

⚪ White — an IR is loaded and active
⬜ Dim — no IR loaded (the NAM model’s output goes straight to the EQ without cab simulation)
🟡 Yellow — the previously used IR file was not found

IR File

Tap the filename area to open the IR picker sheet, which works the same way as the NAM model picker. Supported formats: WAV, AIFF, CAF, M4A, and any format iOS’s AVAudioFile can open.

Stereo IR files are automatically downmixed to mono. Files at any sample rate are resampled to match the current session sample rate using AVAudioConverter.

IR convolution uses a uniform partitioned overlap-save FFT algorithm via Apple’s Accelerate vDSP framework. The partition size is 512 samples, which adds approximately 11 ms of latency at 44.1 kHz (one partition). Homecrate measures and compensates for this latency automatically during recording. See Latency & Compensation.

IR Bypass Toggle

When an IR is loaded, a BYPASS toggle appears. Flip it to hear the NAM model’s output without cabinet simulation — useful for comparing the raw amp character or when using an external cab in your signal chain.

FX Strip

[SCREENSHOT: FX Strip — 5-band EQ and reverb controls]

5-Band EQ

Five frequency bands, each adjustable ±12 dB. All bands use a linear taper.

Knob	Frequency
80	80 Hz (low end / body)
250	250 Hz (low-mid / mud)
800	800 Hz (mid / presence)
3.2K	3.2 kHz (upper mid / bite)
8K	8 kHz (air / pick attack)

Start with all EQ knobs at noon (0 dB). Cut 250 Hz slightly if the tone sounds muddy. Boost 3.2K slightly if you need more cut in a mix.

Room Reverb

Four controls in the SPACE section:

Knob	Parameter	Range	Description
DEC	Decay	0.0–1.0	How long the reverb tail lasts
SIZE	Room Size	0.5–2.0	The perceived size of the simulated space
PRE	Pre-Delay	0–100 ms	Gap before the reverb begins — separates the dry signal from the wash
WET	Wet Mix	0.0–1.0	How much reverb is blended with the dry signal

Keep WET low (0.1–0.2) for most amp sounds. Higher values work for ambient clean tones. Start with DEC around 0.4 and SIZE around 1.0.

Presets

A preset saves the current NAM model, IR file, gain settings, EQ values, and reverb settings as a single named snapshot.

Saving a Preset

Tap + SAVE AS PRESET at the bottom of the interface. Enter a name and tap Save.

[SCREENSHOT: Save preset alert]

Loading a Preset

Tap any preset pill. The plugin immediately loads the saved NAM model, IR, and all parameter values.

[SCREENSHOT: Preset pills at the bottom of the interface]

Deleting a Preset

Long-press any preset pill and tap Delete Preset in the context menu.

Presets are stored in UserDefaults using NSKeyedArchiver, serialized as base64. They reference NAM and IR files by filename (not full path), resolved against homecrate amp’s local file library at load time. If you share a project with someone else, they’ll need to import the same NAM and IR files into their own copy of homecrate amp.

Signal Path Reference

Guitar input
    │
    ▼
Stereo → Mono downmix
    │
    ▼
Input Gain  (0.0–4.0×, Fender taper)
    │
    ▼
NAM DSP  (loaded .nam model — LSTM / WaveNet / ConvNet)
    │
    ▼
IR Convolution  (loaded impulse response, 512-sample partitions)
    │  [bypassed if IR Bypass is on, or no IR loaded]
    ▼
5-Band EQ  (±12 dB at 80 / 250 / 800 / 3200 / 8000 Hz)
    │
    ▼
Room Reverb  (decay / size / pre-delay / wet)
    │
    ▼
Output Gain  (0.0–4.0×, linear)
    │
    ▼
Mono → Stereo broadcast
    │
    ▼
Output to Homecrate track

🔵 Note: If no NAM model is loaded, the signal bypasses the NAM DSP block entirely and passes through with only the gain stages and FX applied. This lets you use homecrate amp as a pure EQ + reverb on non-guitar tracks if needed.

Finding NAM Models

NAM models (.nam files) are shared freely by the guitar community. Popular sources include:

ToneHunt (tonehunt.org) — the largest community NAM model library
NAM’s official GitHub — reference models and documentation
GuitarML community — additional captures and tools

After downloading a .nam file, transfer it to your iPhone/iPad via AirDrop, Files, or iCloud, then use the Browse Files… option in the NAM model picker to import it.

Tips

If your tone sounds thin, try boosting 250 Hz slightly on the EQ
If it sounds harsh or fizzy, cut 3.2K and 8K slightly
Match the Input Gain to how hard you pick — lighter touch = lower input for the cleanest response
Using an IR that matches the style of the NAM model (e.g. a Fender IR with a Fender model) usually sounds most natural
At low IO buffer sizes (1–3 ms), the NAM render block runs on a very tight deadline. If you hear sporadic clicks, increase the buffer to 5 ms — this is the default and handles all common NAM architectures reliably on current devices
The grille cloth fade is a visual-only effect driven by the input gain parameter value — it doesn’t affect audio processing
For recording: set the track input to Plugin Output to capture the processed amp tone directly to an audio clip, which then plays back without needing the plugin active. See Arming Tracks & Input Monitoring
homecrate amp does NOT apply to exported mixdowns — render the processed tone to an audio clip first if you want the amp sim in your final export