Describe Stability Across Recorded Tap Intervals

Describe a completed interval constellation

The YouTube BPM stability checker accepts a list of inter-tap durations in milliseconds. It does not capture events. Paste four to sixty-four values from a completed card or local note, then inspect spread statistics without changing or grading the list.

The word “stability” refers only to numerical variation. It does not judge a tapper, musician, or performance. A wide distribution can reflect expressive tempo, device timing, pulse ambiguity, or input mistakes.

Start with durations, not rounded BPMs

Intervals preserve the timing evidence behind a session. A 500 ms interval corresponds to 120 BPM; 510 ms corresponds to about 117.65. Converting every interval to a rounded BPM first can lose detail. Paste the original millisecond values when available.

The parser accepts one value per line or commas. Each must be 100–4,000 ms under this tool’s declared range. Values outside that range belong in a separate review, not silent normalization.

The statistical ledger

The page sorts a copy of the list while preserving original order. Minimum and maximum show endpoints. Median is the middle value or average of the middle pair. Q1 and Q3 use the median of lower and upper halves. IQR equals Q3 − Q1.

Arithmetic mean uses every interval. Population standard deviation describes average squared distance around that mean. Coefficient of variation divides standard deviation by mean and expresses the result as a percentage. It makes spread somewhat comparable across different average tempos, but it is not an accuracy score.

Fastest interval-equivalent BPM comes from the shortest duration; slowest comes from the longest. The BPM range is fastest minus slowest. Because rate is reciprocal to duration, the order reverses.

For an odd number of values, this checker uses the exclusive median-of-halves rule. With sorted intervals 480, 490, 500, 510, and 520 ms, the overall median is 500 and is excluded from both halves. Q1 is the median of 480 and 490, or 485; Q3 is the median of 510 and 520, or 515; therefore IQR is 30 ms. Publishing that convention prevents two valid quartile methods from appearing to be a calculation defect.

Worked steady-list example

Consider intervals 495, 500, 500, 505, 500, 495, 505, and 500 ms. Sorted values are 495, 495, 500, 500, 500, 500, 505, 505. Median and mean are 500 ms. Q1 is 497.5, Q3 is 502.5, and IQR is 5 ms.

Shortest intervals of 495 ms equal about 121.21 BPM. Longest intervals of 505 ms equal about 118.81 BPM. The interval-equivalent range is about 2.40 BPM. That compact spread describes these eight values only.

Worked irregular-list example

Now consider 480, 490, 500, 510, 520, 760, 500, and 495 ms. The 760 ms gap moves the mean and maximum, widens standard deviation, and lowers the slowest interval-equivalent BPM to about 78.95. Median remains near the central cluster.

This tool does not label 760 an outlier. It may represent a missed tap or a deliberate pause. Use the separate outlier reviewer to apply an explicit median-deviation rule, then return to the original session context before removing anything.

Interpretation without verdicts

A small IQR suggests the middle half of entered durations is concentrated. It does not prove the observer followed the intended pulse. A large coefficient can signal uneven input, but it can also describe a live accelerando or mix transition. Always preserve section, pulse, speed, and device context in a separate observation note.

Do not compare coefficients from sessions that use different input methods or radically different musical questions without explanation. Keyboard and pointer taps can have different physical timing. Background browser activity can affect events.

Preserve original order beside the sorted view

Quartiles require sorting, but musical timing unfolds in sequence. A session that gradually changes from 520 to 480 ms can have the same sorted distribution as one that alternates erratically between those values. The result therefore shows both ledgers. Use the original order to look for a trend and the sorted order to inspect distribution.

For chronological analysis beyond a visual review, create separate session cards rather than claiming this checker detects acceleration. It supplies descriptive ingredients only. A copied report should state the interval unit and count so milliseconds are not mistaken for BPM values.

Tool limits and privacy

The checker cannot see chronology after sorting unless the original list is consulted. It cannot determine causes, detect media, choose a correct pulse, or repair intervals. It does not calculate source-speed correction or candidate levels.

No YouTube link, player, audio, video, microphone, API, account, or database is used. The pasted list and output remain in current-page memory until Reset, reload, or closure.

Frequently asked questions

Paste the completed interval list, compare median and IQR with the full range, and return to the original observation before interpreting any wide gap.