S/Z Ratio is an evaluation utility for speech-language pathologists who provide assessment and/or treatment to clients with voice disorders.

With a built-in stopwatch feature, S/Z Ratio allows for the timing of a clientʼs /s/ and /z/ maximum phonation times. Once maximum phonation times are taken, an s/z ratio is instantly calculated. Calculated ratios are displayed in a color-coded fashion to provide visual feedback for quick interpretation of testing results. A reference information screen is also included to assist clinicians and clients in interpreting the obtained s/z ratio results.

Consider using this application throughout the evaluation and treatment process: (1) during initial evaluations, (2) as a screening tool to identify the need for further assessment, (3) during treatment sessions for visual, instant feedback, and (4) as a re-evaluation measure of progress based on therapeutic interventions.

Whether you specialize in voice therapy or provide treatment to the occasional client with voice disturbances, this application is a must-have. S/Z Ratio provides a wealth of features including:

- Built-in stopwatch
- Instant calculation of ratio
- Color-coded display of ratios
- Reference information screen for assistance in interpreting results
- Single touch Start, Stop and Reset stopwatch buttons
- Large, easy to read display
- Displays /s/ and /z/ maximum phonation time simultaneously for easy review and discussion with clients

Replace your stopwatch and calculator with this app today, and gain some much needed time and pocket space as a result!

What's New

Version 1.1

Universal update - Now runs natively on iPhone & iPad.
Added a global reset button to reset both /s/ and /z/ durations with a single tap.
Updated icon.

Ratings and Reviews

4.2 out of 5
13 Ratings
13 Ratings

Will use immediately!


App is fast and intuitive to use, gives instant feedback (+ motivation) via real-time stopwatch. I will switch from cumbersome hand-timing now. And I can quit just writing "moderately breathy voice" in writeups & have a real baseline. A great addition to my daily-use "in the field" SLP eval toolkit.

Convenient, but not much better than a stop watch.

Schrodinger's Other Cat

Generally with S/Z, you want to take the maximum time. It would be much better if you could measure x3 and take /choose the longest for the comparison. Instead, it only stores 1 S and 1 Z at a time.
Does the norms for you, but isn't much better than a stopwatch as is. If it used 3/would save the longest, then it'd be worth the price.

Love it


So quick & easy.... Time saver is always a plus in the day and age of productivity standards...


Meld Apps
1.6 MB
Requires iOS 3.0 or later. Compatible with iPhone, iPad, and iPod touch.
Age Rating
Rated 4+
© 2010 Meld Apps, LLC


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