ObieWebApp

All three tools are browser-based and run entirely locally — nothing is uploaded to any server. They use the File System Access API (Chrome or Edge 86+ required) to read and write files in a folder you choose on your computer.

Select a Data Folder

Before using any tool, click the Data Folder button (on the home page or inside any tool) and select the folder that holds your measurement files. The folder name is remembered between visits. Grant read/write access when the browser asks — this allows the tools to load FRF files and save new measurements automatically.

Supported file formats

Explore lets you load multiple FRF files at once, overlay them on a single interactive plot, and compare them with smoothing, normalization, band averaging, and per-dataset convolution playback.

Loading files

Three ways to load FRF files:

1. Browse — opens a file picker; select one or more FRF files directly. Accepts AvR, AvC, TRF, TRV, CSV, and MAT formats.
2. Search — opens the Search modal. Type a filename pattern (comma-separated for OR logic), filter by file type, and load all matching files from your Data Folder with one click.
3. Drag & drop — drag files from your desktop onto the plot area.

Hover tooltip

Hovering over any point on the plot shows: Amp = 18.4 dB   Freq = 443 Hz  (A = 440 Hz). The note name and its exact reference frequency (nearest equal-temperament pitch) are shown automatically whenever the cursor is over an FRF trace.

Plot controls

Dataset list (left panel)

Band averaging

Select a band preset from the Bands dropdown (presets are loaded from ObieAppSettings/bands/ in your Data Folder). The band table shows one column of results per visible dataset — average dB level and spectral centroid for each band, in each dataset's colour. Toggle shade to highlight the band regions on the plot. Click Excel to export all datasets' band data as a CSV file.

Group averaging & saving

Set the Normalization dropdown to Complex average or Real average to overlay one averaged trace across all currently visible datasets. Complex average converts each dataset's dB magnitude to linear amplitude before averaging (then back to dB); Real average takes the arithmetic mean of the dB values directly. Complex average is only selectable when at least one visible dataset carries complex/phase data (e.g. loaded from an AvC or a complex TRF).

With one of those modes active, right-click the plot for a 💾 Save to Group Averages… option — name the average and save it as a CSV or an AvR file into a Group Averages folder created at the root of your Data Folder.

Interpret

Click Interpret to open a reference overlay with two sections:

• Mode labels — the standard Oberlin mode labels (A0, CBR, B1−, B1+, Bridge Hill, etc.) drawn as shaded regions on the current plot. Includes links to violinacoustics.com and euphonics.org.
• Note Harmonics — click any of the 12 chromatic note buttons (G3 – F♯4) to overlay blue dotted vertical lines at the fundamental frequency of that note and all of its overtones up to 10,500 Hz. Click the same note again to remove the lines. Useful for checking whether a resonance peak lines up with a specific played note.

Other toolbar buttons

Convolve applies a measured FRF to a dry audio file using full complex frequency-domain convolution: Y(f) = H(f) · X(f). The result sounds like the dry signal played through (or by) the measured instrument.

Step-by-step workflow

1. Load an FRF. Under FRF Files, click Left / Mono FRF and pick an AvR, AvC, TRF, or CSV file. For stereo output, also load a Right FRF; the tool then produces a two-channel result with independent left and right filtering.
2. Load a WAV. Under Signal (WAV), click Load WAV and select any WAV file (mono or stereo). Use ▶ Play WAV to confirm the dry signal.
3. (Optional) Pick an output device. Under Settings, choose where playback should go from the Output device dropdown.
4. Convolve. Click ⚡ Convolve. The button is enabled only once both an FRF and a WAV are loaded.
5. Listen and save. Press ▶ Play Result to audition, then 💾 Save to download the convolved WAV to your computer.

The four plots

Acquire turns your laptop and a USB audio interface into an impact-hammer FRF measurement system. It records hammer and microphone signals simultaneously, detects hits automatically, averages multiple hits per position, and saves a TRF per position plus AvR/AvC averages at completion (see What gets saved below).

Hardware setup

1. Connect your USB audio interface (e.g. Focusrite Scarlett 2i2) before opening the page.
2. By default, plug the impact hammer into Input 1 (left) and the microphone into Input 2 (right). Enable Swap channels in Template & Settings if your hardware is wired the other way around.
3. Use Chrome or Edge — Safari and Firefox do not support the required audio APIs.

Instrument and test name

Click the 🎻 Instrument button in the toolbar to name the violin or instrument being measured. Acquire creates a folder named after the instrument inside your Data Folder, and automatically numbers successive test runs (Violin_01, Violin_02, …). The floppy-disk icon next to the test name lets you rename the current run — the folder on disk is renamed to match.

First-time setup (Template & Settings)

Click Template: in the toolbar to open the Template & Settings dialog and configure:

Plot Settings (inside Template & Settings)

The Plot Settings column controls the axis limits for all four plots, each shown as a single X axis range and Y axis range row (min – max):

These axis limits are saved with your settings and are part of templates — loading a template restores all axis ranges.

Agenda checklist

The right-hand info panel starts with an ✨ Ask Claude button, followed by an Agenda checklist above Run Settings. Ask Claude opens a new Claude.ai chat in another tab with a question started for you, pointing Claude at ObieWebApp's documentation — finish typing your question and send it (nothing is sent automatically). The Agenda is a step-by-step reminder for the full workflow, grouped into two sections:

Click a step to check it off; it strikes through and the state persists across reloads. The whole checklist clears automatically the next time you press ▶ Start from idle or a completed run, ready for the next one.

Running a measurement

1. Click 📁 Data Folder and select the folder where results should be saved.
2. Name your instrument via the 🎻 Instrument button.
3. Click ▶ Start. The app begins listening for hammer hits.
4. Strike the instrument. The three mini plots (Hammer FFT, Hammer time, Mic time) update after each hit. Check that the hammer pulse is clean — a double-hit shows two bumps in the Hammer time plot.
5. After the required number of good hits the Position complete dialog appears. Choose Next Position → to advance (the mini plots and current FRF clear for a fresh start) or Repeat to re-do the current position.
6. Use ↩ Undo Hit to remove a bad last hit, or 🗑 Clear H01 to restart the current position. ↺ Start over clears all positions.
7. When all positions are complete, AvR/AvC averages are saved automatically (per prefix group, plus a combined set if you used more than one — see What gets saved below) and a Run complete banner appears.
8. To start the next run on the same instrument, click ▶ Start again — the test name increments automatically (e.g. Violin_01 → Violin_02) and all positions reset.

Reviewing the FRF plot

The main plot shows the current position's FRF building up with each hit, along with a coherence overlay (γ², scaled to the bottom third of the Y range). When you advance to the next position the plot clears so you start fresh — previous positions are saved on disk and can be loaded in Explore. Use the plot-toolbar controls to toggle log/linear X axis, rescale Y, or adjust the dB range.

Templates

A template stores your complete measurement setup — trigger settings, calibration factors, position count, and all plot axis limits. Templates live in ObieAppSettings/Templates/ inside your Data Folder.

1. Click Template: in the toolbar to open the Template & Settings dialog.
2. Click a template in the list — it applies immediately (fields update right away). An Undo button reverts an accidental click.
3. The primary button at the bottom reads Use Template when your settings still match the applied template. Editing any field switches it to Update and Use Template, which saves your changes back into that template as well as applying them. With no template applied, it reads Use Settings and applies your changes to this run only.
4. To save the current settings as a brand-new template, click Create New Template.
5. Reset Default Templates re-downloads the built-in templates ("HV 24 Obie Rig", "ScratchPad", "Scratchpad Obie 26") without touching your custom ones.

Audio device disconnect

If the USB audio interface is unplugged or interrupted while acquisition is running, Acquire stops immediately and shows an alert. Re-plug the device and click ▶ Start again. If you change the selected input device in Settings while audio is active, the audio stream restarts automatically on the new device.

Session Notes

Click Notes (next to the Template button) to open the Notes panel and enter free-text observations about the session. Notes save to notes.txt in the instrument's folder and are shown in Explore when you hover that instrument's datasets. The first time you open Notes for an instrument with no existing file, it's pre-filled with a fill-in-the-blanks template (date/time, location, experiment, researchers, instrument info, measurement info) to fill in or delete as needed.

Use 🗑 Delete Notes & Start Again (with a confirmation prompt) to clear the notes and remove notes.txt from disk. 📷 Add Photos… attaches one or more image files to the instrument, and 📸 Camera opens a live preview from your computer's webcam with a Snap button to capture and save a photo directly — both save into a photos folder alongside the notes. Saved photos are shown as thumbnails; click one to open the full-size image in a new tab.

LiveView

Click LiveView to open a full-screen view of the FRF plot — useful when the laptop is placed at a distance from the instrument during measurement.