Class II Voice Analysis Instrument

Computerized Speech Lab (CSL), Model 4150B

Computerized Speech Lab (CSL), Model 4150B, is a highly advanced acoustic analysis system with robust hardware for data acquisition complemented by the most versatile suite of software available for speech/voice analysis, measurement, and therapy.

KayPENTAX offers two versions of the CSL hardware: Model 4500 (described in a separate section) and Model 4150B. Both platforms share many similarities, but Model 4150B is lower cost because, comparatively, it contains slightly reduced specifications (see table of differences below). Although these differences are meaningful for some applications, CSL 4150B should be viewed as a highly cost-effective system depending on the user’s requirements. The two CSL models are state-of-the-art input/output audio devices for a PC, and meet the exacting requirements for reliable acoustic measurements both in the clinic and for research.

CSL Hardware Module Advantages

CSL 4150B contains an external module with user controls and an internal plug-in card for the host computer. The external module offers many advantages over systems using an internal I/O card. Among these are convenient access to all input/output jacks (e.g., for microphone and headphones) and easy volume adjustments. During speech input, the signal level is readily adjusted with an external knob to ensure optimal data acquisition with the broad range of voice amplitudes encountered in the clinic. For the Voice Range Profile program, a calibrated input, which is activated by a switch on the external module, ensures precise dB SPL measurements. CSL hardware was designed from the ground up to meet the challenging demands of speech acquisition and accurate measurement. In addition to the many user conveniences, the external module provides rigorous signal conditioning (e.g., preamplification and anti-aliasing filters) resulting in accurate representation of the digitized signals. The signal-to-noise specification of the CSL exceeds 90 dB, which meets the recommended specifications of the National Center for Voice and Speech (NCVS).

Comprehensive Software for Speech/Voice Analysis

Complementing CSL hardware is a suite of some 20 software options. These include programs for patient assessment and therapy covering a broad range of communication disorders including voice, motor speech, fluency, and articulation. No other system provides the breadth of application-specific programs, many of which are frequently cited in peer-reviewed articles as the software tools of choice. The wealth of separate software options enables clinicians and researchers to tailor a CSL system to their work requirements. Various, cost-effective software “packages” are also available for different work settings. Additionally, CSL software includes a variety of databases and educational programs making it an ideal teaching platform for educators.


In keeping with its leadership position as the gold standard acoustic analysis system, CSL has undergone continual refinements over the past decade with on-going hardware improvements and software expansion. It is used by leading clinicians and speech scientists for speech/voice measurements, clinical feedback, teaching, second language acquisition, and forensics work. CSL 4150B is a cost-effective choice for those who require a sophisticated hardware system coupled with unmatched software versatility.

Differences Between CSL 4150B and CSL 4500

CSL 4150B: Two input channels; 8,000 – 50,000 Hz sampling frequency range (per channel); AC coupling CSL 4500: Four input channels; 8,000 – 200,000 Hz sampling frequency range (per channel); AC and DC coupling

CSL 4150 Abbreviated Specifications Analog Inputs: 2 Channels: 2 XLR and 2 Phono-type; AC Coupling; calibrated input for VRP; digital attenuator: 0-52dB, 24 bit A/D; sampling rates: 8,000-50,000 Hz; dynamic range: >90dB; frequency response (AC coupled): 5 Hz to 20 kHz (-3dB) at 44.1 kHz Digital Interface: AES/EBU or S/P DIF format; transformer-coupled Software Interface: ASIO and MME Computer Interface: PCI (Version 2.2-compliant), PCI Card, 5.0” H x 7.4” W x 0.75” D (Half-sized PCI Card) Analog Output: 2 Channels: Line and speaker; headphone output Physical: 4” W x 8.25” H x12.5” D; 4 lbs. 12oz.; 45 watts; speaker; and microphone (Shure SM-48 or equivalent, XLR-type)

Software Options for the CSL Family (grouped in categories)

Clinical Assessment and Real-Time Feedback Applications

-Auditory Feedback Tools, Model 3506

-Games, Model 5167

-Motor Speech Profile, Model 5141

-Multi-Dimensional Voice Program, Model 5105

-Real-Time EGG Analysis, Model 5138

-Real-Time Pitch, Model 5121

-Real-Time Spectrogram, Model 5129

-Sona-Match, Model 5127

-Voice Range Profile, Model 4326

Linguistics and Forensics Applications

-Analysis-Synthesis Laboratory (ASL), Model 5104

-Signal Enhancement Program, Model 5142 Databases

-Disordered Voice Database and Program, Model 4337

-Palatometer Database, Model 4333

-Phonetic Database, Model 4332

-Video Phonetics Program and Database, Model 5150

Educational Software for Teaching Applications

-Applied Speech Science for Dysarthrias, Model 5153

-Applied Speech Science for Voice & Resonance Disorders

-Neuroscience for Human Communications

-Phonetic & Perception Simulation Programs, Model 5151

-Respiration, Phonation and Prosody Simulation, Model 5152

-Speech Articulation: Animation of Muscle Vectors

For more information on CSL or other KayPENTAX products, contact the company ( For information on related acoustic analysis systems from KayPENTAX, see:

Visi-Pitch IV, Model 3950

Multi-Speech, Model 3700