Your voice has a spectral signature.
See yours.
Prosodic analysis built on the original paper. Calibrate with a neutral sentence, say anything you like, and watch where the second utterance lands on the cartesian plane of naturalness and tension. An exploration tool for anyone.
How it works
Three simple steps. No sign-up for your first test.
Calibrate
Record 5–10 seconds reading a neutral sentence the system gives you. That audio sets your personal baseline.
Record
Say any sentence. It can be true, made up, or a joke. The system processes it in seconds.
See
The result appears on a cartesian plane comparing your second sentence against the baseline. Save it, compare, explore.
What it is not
Scientific honesty first. Vox Probabilis V1 is a tool for exploration and curiosity — not a polygraph, not a lie detector, not a forensic instrument, not a medical diagnosis. The prosodic features (jitter, MFCC delta variance, spectral flux, microtremor envelope) reveal patterns of variation in the voice. Interpreting those patterns depends on context the system has no access to. Use it with curiosity, not with certainty.
Coach + Academic — everything at once
Unlimited sessions and analyses across both products, in a single plan.
Hearings as teaching material.
Prosodic analysis for the study of law.
For students and professors studying the structure of oral testimony. Upload public hearings or cases already settled, and see how the spectral signal speaks to courtroom strategy. Learn the texture of a hearing before you ever step into one.
A real hearing from the Small Claims Court of Santo André, Brazil (case 1007542-44.2020.8.26.0554). Each point is a phase of the hearing; each color is a witness. Notice how one migrates across quadrants under pressure from opposing counsel, while the other holds a stable profile.
What it is — and what it is not
Use it for
- Classes on procedural law, oral testimony, examination technique
- Independent study of landmark hearings
- Theses and academic research
- Lesson planning and mock-hearing prep
- Recognizing a witness's prosodic texture under pressure
- Comparing patterns across hearings from the same court
Don't use it for
- Attaching to court filings or legal opinions
- Deciding a witness's credibility in an active case
- Replacing technical expert review or forensic audio analysis
- Analyzing hearings under seal or court confidentiality
- Binary labeling of "truth" or "lie"
- Training AI or selling the analyses you generate
How it works
Upload, confirm the phases of the hearing, analyze. Three teaching-ready steps.
Upload the hearing
Accepts audio in .wav, .mp3, .opus, or .m4a, up to 200 MB. Declare eligibility (public hearing or a settled case).
Confirm the phases
The system detects them automatically: opening, calibration, examination by the judge, cross-examination by opposing counsel. You review.
Read the report
Cartesian plot, color-coded transcript, per-witness summary. Open methods — reproduce it yourself if you like.
Plans
For the individual student, the professor, or an entire faculty. All with 36% off on the annual plan.
- One complete hearing
- Report with cartesian plot
- Access to the methodology
- No credit card
- Pay only when you use it
- Full report
- Access to the methodology
- No subscription
- 60 analyses per month
- 82 analyses on the annual plan
- Save sessions to your account
- Unlimited history
- Email support
- Unlimited analyses
- Share with students
- Templates by course
- Priority support
- Multiple professors
- Centralized seat management
- Billing per institution
- Dedicated onboarding and support
Coach + Academic — everything at once
Unlimited sessions and analyses across both products, in a single plan.
Coach your client with an objective signal.
Preparation you can see.
For practicing lawyers preparing clients or witnesses. A live session, captured natively in the browser, baseline calibrated in seconds, and prosodic feedback in real time after every answer. What used to be intuition is now also signal.
What it is — and what it is not
Use it for
- Preparing a client for personal testimony
- Coaching a witness you've called before the hearing
- Spotting rehearsed answers that come across as tense
- Running a question set that mirrors what opposing counsel would ask
- Tracking how a client's baseline evolves across sessions (Tier 2+)
- Narrative reports to review after the session
Don't use it for
- Producing court evidence or attaching to legal filings
- Analyzing a witness for the opposing side
- Diagnosing who is telling the "truth" or a "lie"
- Coercing a client or using it against their interest
- Replacing your professional judgment — it's support, not the answer
- Sharing results without the client's consent
How it works
A live session, the browser, a microphone. Nothing to install, no file uploads.
Create the session
Name it, and optionally paste the question set you plan to rehearse. You get a session link for you or your client to open.
The client calibrates
The client speaks a neutral sentence for 8 seconds. The system measures the microphone SNR, sets the session baseline, and unlocks the practice loop.
Practice and see
A "Question" button, an "Answer" button, a "Stop" button. In 2–3 seconds the answer card appears with a color-coded indicator and a narrative of what changed relative to the baseline.
Plans
For the solo lawyer or the firm. 1 month free on any plan — including the prepaid ones, which still get a discount. Cancel anytime.
- 4 sessions per month
- 20 answers per session
- PDF reports
- Real-time indicator
- No audio retention
1 month free, then $33.33/mo. Cancel anytime.
Or prepay: 6 months $133.30 · annual $222.22
Subscribe to Starter- Unlimited sessions
- Unlimited answers
- Pre-Hearing Brief with Claude Opus
- Vault: persistent clients, cross-session trajectory, diff
- PDF reports
1 month free, then $77.77/mo. Cancel anytime.
Or prepay: 6 months $333.30 · annual $533.30
Subscribe to ProCoach + Academic — everything at once
Unlimited sessions and analyses across both products, in a single plan.