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Jakub Charkiewicz

Founder & lead reviewer

Jakub Charkiewicz

Jakub Charkiewicz is a technology entrepreneur, content creator and audio reviewer based in Warsaw, Poland, and the founder and managing director of The Audio Stuff.

Jakub by the numbers

Reviews
66
Buying guides
12
Categories
8
Brands
31
Writing since
May 2023

Figures as of , the date of Jakub's latest piece.

About Jakub

I founded The Audio Stuff in 2023 and run it as managing director. I write, listen to, score and sign off every review that carries my name, and I present the reviews on the publication's YouTube channel.

My approach to business and to content comes from a lifelong passion for science and physics. That analytical habit is what lets me understand software, acoustics and digital platforms at a fundamental level. Put together with the commercial side of the work, it lets me break the technical detail down for the people reading and watching, build digital campaigns and grow active online communities around them.

Alongside the reviews, my company works in e-commerce, marketing and distributing software licenses online, and I run its social media. My core expertise is business leadership and team management: scaling operations, streamlining e-commerce workflows and mentoring the people I work with. Whether it is the physical properties of sound in a new review, the numbers behind a marketing funnel or the next business decision, I enjoy solving complex problems, and I am always glad to hear from other digital entrepreneurs, tech innovators and creators.

Areas of expertise

  • Audiophile headphones - planar magnetic, dynamic, electrostatic, IEMs
  • Hi-fi loudspeakers and studio monitors
  • R-2R and delta-sigma digital-to-analog converters
  • Headphone amplifiers and integrated amps - Class A, AB, D, and tube
  • Room acoustics, standing-wave measurement, and bass treatment
  • ABX double-blind testing methodology and audio measurement
  • The audio industry as a business - ownership, acquisitions and product launches

Jakub's reviews

66 reviews across 8 categories, published Jun 2023 to Sep 2026. Every one has a video on the channel. The reference chain and listening room they are heard on are described in How we test.

Verdicts given

  • Reference 3 of 66 reviews
  • Highly Recommended 24 of 66 reviews
  • Recommended 34 of 66 reviews
  • Mixed 5 of 66 reviews
  • Pass 0 of 66 reviews

Each verdict has a published score band.

Headphones 28

Speakers 6

DACs 8

Headphone Amps 4

Speaker Amps & Preamps 3

Digital Sources 1

Microphones & Recording 3

Accessories 13

Jakub's buying guides

Background

Experience

  1. to present

    Managing Director

    The Audio Stuff (self-employed)

  2. Software Engineer Intern

    INTRATEL Sp. z o.o. (internship), Białystok, Podlaskie, Poland · On-site

    A one-month software development internship across the full development cycle: designing, implementing and testing programming and database solutions for live IT systems, gathering project requirements, writing the technical documentation and working through the company's task management system. Completed as part of the INFOTECH vocational program for IT technicians.

    Skills: Technical Documentation, Software Development, Requirements Analysis, Software Testing, Task Management, Project Planning

    Documents: Official Performance Evaluation & Project Duties; Certificate of Completion - Software Development Internship

Education

  1. to (in progress)

    Master's degree, Law

    University of Warsaw

  2. to

    Technician degree, Computer Science

    Technikum Programistyczne INFOTECH

    A five-year technical program at a specialized programming high school, built on computer science and software development: database architecture, algorithm design and core information-technology principles, with hands-on embedded-systems and hardware work through Arduino projects, from system architecture to software engineering.

    Activities: Advanced Mathematics and Programming track; school event coordination and organizational support.

    Skills: Python (Programming Language), SQL

    Documents: Certificate of Graduation in Software Engineering and IT

Languages

English (native or bilingual) and Polish (native or bilingual).

Skills

Industry knowledge
Technical Documentation, Software Development, Requirements Analysis, Software Testing, Task Management, Project Planning, Programming Concepts, Algorithms, Data Structures, Computer Science, Prompt Engineering, Threat & Vulnerability Management, Information Security Awareness, Cybersecurity, Technical Leadership, Organizational Leadership, Machine Learning, Agile Project Management, Agile Methodologies, Data Engineering, Artificial Intelligence (AI), IT Service Management, IT Management Monitoring, Change Management, Financial Forecasting, Financial Analysis, Probability, Statistics, Statistical Data Analysis, User Management, Linux System Administration, CLI, Business Operations, Business Process Improvement, Operations Management, Lean Operations, Financial Statement Analysis, Financial Modeling, Environmental, Social, and Governance (ESG), Corporate Finance, Strategic Negotiations, Professional Communication, Project Management, Project Communications, Budget Development, Requirements Management, Project Scheduling, Speech Writing, Presentation Skills, Written Communication, Business Communications, Business Writing, Managerial Finance, Management Accounting, Financial Accounting, Cloud Security, Governance, Risk Management, and Compliance (GRC), Microsoft Security, Data Science, Cash Flow Management.
Tools and technologies
Python (Programming Language), SQL, Jira, Microsoft Excel, Wolfram Language, Ubuntu, Grammarly, Hootsuite, MailChimp, Adobe InDesign.
Interpersonal skills
Communication, Analytical Skills, Negotiation, Interpersonal Skills, Public Speaking, Conflict Resolution, Active Listening, Interpersonal Communication.
Other skills
Microsoft Copilot, Generative AI, AI for Business, Responsible AI, AI Policy, Governance, and Regulation, AI Productivity, Break-even Analysis, Ratio Analysis, Financial Statements, Social Media Marketing, Content Marketing, Brand Storytelling, Hiring, Talent Management, Recruiting, Job Description Development, Data Governance, Data Warehousing, Marketing Strategy, Email Marketing, Data Analysis.

Licenses and certificates

69 certificates from 44 issuing organizations, to .

Language 1

  • telc English B1, issued by telc gGmbH, , credential ID 4250842. Passed with a "Very Good" overall grade, the highest available.

Software, cloud and IT 21

  • SS&C Blue Prism Robotic Process Automation Professional Certificate, issued by SS&C Blue Prism,
  • TestMu AI Test Automation Professional Certificate, issued by TestMu AI (formerly LambdaTest),
  • Network Automation Professional Certificate by Arista Networks, issued by Arista Networks,
  • JavaScript Foundations Professional Certificate by Mozilla, issued by Mozilla,
  • Microsoft Azure Essentials Professional Certificate by Microsoft and LinkedIn, issued by Microsoft,
  • OpenEDG Python Institute: Programming with Python Professional Certificate, issued by OpenEDG Python Institute,
  • Kotlin Professional Certificate by JetBrains, issued by JetBrains,
  • Career Essentials in GitHub Professional Certificate, issued by GitHub,
  • Penetration Testing Professional Certificate by Cybrary, issued by Cybrary,
  • Docker Foundations Professional Certificate, issued by Docker, Inc,
  • Career Essentials in GitHub Copilot Professional Certificate, issued by GitHub,
  • TestMu AI Software Testing Professional Certificate, issued by TestMu AI (formerly LambdaTest),
  • Cloud Strategy Professional Certificate by LinkedIn Learning, issued by LinkedIn,
  • Microservices Foundations Professional Certificate by Kong, issued by Kong,
  • ServiceNow IT Leadership Professional Certificate, issued by ServiceNow,
  • DevOps Professional Certificate by PagerDuty and LinkedIn, issued by PagerDuty,
  • Microsoft Security Essentials Professional Certificate by Microsoft and LinkedIn, issued by Microsoft,
  • Ubuntu Linux Professional Certificate by Canonical, issued by Canonical,
  • Atlassian IT Service Management (ITSM) Professional Certificate, issued by Atlassian,
  • Career Essentials in Cybersecurity by Microsoft and LinkedIn, issued by Microsoft,
  • PCEP - Certified Entry-Level Python Programmer, issued by OpenEDG Python Institute, , credential ID VkF8.ETBX.qPEd. Python fundamentals: programming concepts, data structures and algorithms.

Data, AI and machine learning 16

  • AI for Nonprofits Professional Certificate by Microsoft Elevate, LinkedIn, and NetHope, issued by NetHope,
  • Machine Learning Statistical Foundations Professional Certificate by Wolfram Research, issued by Wolfram,
  • Responsible AI Foundations Professional Certificate by All Tech Is Human, issued by All Tech Is Human,
  • Anaconda Python for Data Science Professional Certificate, issued by Anaconda,
  • Generative AI for Sales with Microsoft 365 Copilot Professional Certificate, issued by Microsoft,
  • Generative AI for Marketing Professional Certificate by the American Marketing Association, issued by American Marketing Association,
  • Career Essentials in Data Analysis by Microsoft and LinkedIn, issued by Microsoft,
  • Vector Databases Professional Certificate by Weaviate, issued by Weaviate,
  • Data Engineering Foundations Professional Certificate by Astronomer, issued by Astronomer,
  • Data Science Professional Certificate by KNIME, issued by KNIME,
  • Statistics Foundations Professional Certificate by Wolfram Research, issued by Wolfram,
  • Responsible AI in a Global Context Professional Certificate by the United Nations University, issued by United Nations University,
  • Generative AI Professional Certificate by Snowflake, issued by Snowflake,
  • Machine Learning with Python Professional Certificate by Anaconda, issued by Anaconda,
  • AI for Organizational Leaders by Microsoft and LinkedIn, issued by Microsoft,
  • Career Essentials in Generative AI by Microsoft and LinkedIn, issued by Microsoft,

Management, operations and finance 19

  • CSCMP Supply Chain Foundations: Procurement Professional Certificate, issued by CSCMP - Council of Supply Chain Management Professionals,
  • LinkedIn Learning Professional Certificate: Leading the Future as a Senior Executive or C-Suite Leader, issued by LinkedIn,
  • Career Essentials in Business Analysis by Microsoft and LinkedIn, issued by Microsoft,
  • Project Management for Supply Chain Professional Certificate by CSCMP, issued by CSCMP - Council of Supply Chain Management Professionals,
  • CSCMP Supply Chain Foundations: Customer Relationship Management Professional Certificate, issued by CSCMP - Council of Supply Chain Management Professionals,
  • Human Resources Foundations by the Chartered Institute of Personnel and Development (CIPD) and LinkedIn, issued by CIPD,
  • LinkedIn Learning Professional Certificate: Leading Teams as a People Manager, issued by LinkedIn,
  • Aha! Product Management Professional Certificate, issued by Aha!,
  • CSCMP Supply Chain Foundations: The Essentials Professional Certificate, issued by CSCMP - Council of Supply Chain Management Professionals,
  • Human Skills for Managers Professional Certificate by LinkedIn Learning, issued by LinkedIn,
  • American Staffing Association Corporate Recruiting Professional Certificate, issued by American Staffing Association,
  • Finance for Managers Professional Certificate by LinkedIn Learning, issued by LinkedIn,
  • Accounting Foundations Professional Certificate by Xero, issued by Xero,
  • Career Essentials in Project Management by Microsoft and LinkedIn, issued by Microsoft,
  • Negotiation Professional Certificate by American Negotiation Institute, issued by American Negotiation Institute,
  • CFI Corporate Finance Foundations Professional Certificate, issued by Corporate Finance Institute (CFI),
  • Operations Management Professional Certificate by Jack Welch Management Institute, issued by Jack Welch Management Institute,
  • CFI Financial Analysis and Modeling Professional Certificate, issued by Corporate Finance Institute (CFI),
  • Atlassian Agile Project Management Professional Certificate, issued by Atlassian,

Marketing, sales and communication 12

  • Essential Skills in Adobe Firefly Professional Certificate, issued by Adobe,
  • Sales Operations Foundations by the Sales Management Association and LinkedIn, issued by The Sales Management Association,
  • Digital Marketing Professional Certificate by Content Marketing Institute, issued by Content Marketing Institute,
  • Sales Foundations Professional Certificate by the National Association of Sales Professionals, issued by NASP - National Association of Sales Professionals,
  • Sales Management Foundations Professional Certificate by the Sales Management Association and LinkedIn, issued by The Sales Management Association,
  • Essential Skills in Adobe InDesign 2025 Professional Certificate, issued by Adobe,
  • Search Engine Optimization Professional Certificate by Moz, issued by Moz,
  • Email Marketing Professional Certificate by Intuit Mailchimp, issued by Intuit Mailchimp,
  • Social Media Marketing Professional Certificate by Hootsuite, issued by Hootsuite,
  • Business Writing Professional Certificate by Grammarly, issued by Grammarly,
  • Essential Business Communication Skills Professional Certificate by LinkedIn Learning, issued by LinkedIn,
  • Public Speaking Skills Professional Certificate by Toastmasters International, issued by Toastmasters International,

Corrections

22 corrections have been logged on Jakub's reviews, each on the review it corrects with the date it shipped:

  • , Synergistic Research Network Router UEF review

    The linear power supply was described as adapted from the Galileo PowerCell; Synergistic Research describes it as similar to its SR LPS UEF. The box contents are corrected to the 5 ft Foundation 12 AWG power cable and the installed SR Pink Fuse; the MiG 4.0 footers are now described as having come with the review unit, since Synergistic Research does not list them in the standard box.

  • , HIFIMAN Serenade review

    Weight corrected from about 3 kg to 3.9 kg, and Bluetooth removed from the inputs: the unit reviewed is the non-Bluetooth Serenade, which has no antenna socket, per HIFIMAN's published specifications. The DAC is also described as HIFIMAN specifies it, a 24-bit Himalaya Pro module that accepts up to 32-bit/768 kHz and DSD512 over the network.

  • , Meze 105 Silva review

    Weight corrected from 350 g to 354 g, and the driver described as Meze does (a carbon fiber-reinforced cellulose W-dome with a titanium-coated torus, not a carbon-fiber driver), to match Meze's published specifications.

  • , Synergistic Research PowerCell 14 review

    Weight corrected from 12 kg to 12.7 kg (28 lb), to match Synergistic Research's published specifications; dimensions added from the same specifications.

  • , Tonewinner AD-1PA+ review

    Specifications corrected to Tonewinner's own: 330 W per channel into 8 ohms (the 100 W Class A, 300 W Class AB and 500 W into 4 ohm figures were a dealer's), 42 kg, THD 0.008%, SNR 115 dB (108 dB balanced), 10 Hz - 100 kHz, 4-8 ohm loads rather than 2 ohms, a 260-300 W draw in Class A rather than 1200 W, and 16 output transistors for 120 A. The amplifier also has an auto-switch mode, so the con saying it had none was removed.

  • , Taga Harmony TAV-607F review

    Frequency response corrected from 44 Hz - 25 kHz to 40 Hz - 25 kHz; power handling from 120 W RMS (240 W peak) to 90 W RMS, with 20-120 W as the recommended amplifier power and no peak figure; the reflex port from rear to front; and the 6.5-inch midrange added to the driver list - all to match Taga Harmony's published specifications.

  • , Taga Harmony PF-1000LPS review

    The PF-1000LPS was called a power conditioner; Taga classes it as a power noise filter (its PC series are its conditioners), so the title, description and product type now say filter. Weight and dimensions added from Taga's specifications.

  • , Triangle Australe EZ review

    Weight corrected from 40 kg (90 lb) to 38.8 kg (85.5 lb) per speaker, to match Triangle's published specifications; dimensions added from the same specifications.

  • , Verum Audio Verum 1 review

    Sensitivity corrected from 96 to 107 dB/mW, to match Verum Audio's published specifications; weight added from Verum Audio's specifications.

  • , AudioMica 4-all-in-1 Cable Set review

    Cable diameters corrected from 11.5 mm for the power cable, with the speaker cable about 1 mm thicker, to about 12.5 mm for the power cable and about 12 mm for the speaker cable, to match AudioMica's published specifications.

  • , Triangle Borea BR09 review

    Weight corrected from 23 kg to 23.4 kg per speaker, to match Triangle's published specifications; dimensions added from the same specifications.

  • , Yellowtec PUC2 Mic LEA review

    Dynamic range corrected from 114 dB to 108 dB, to match Yellowtec's published specifications.

  • , HIFIMAN Ananda Stealth review

    Weight corrected from 400 g to 398 g, to match HIFIMAN's published specifications.

  • , SMSL DO100 PRO review

    Weight corrected from 1.5 kg to 1.45 kg, to match SMSL's published specifications.

  • , Tonewinner AD-2PRO+ review

    Weight corrected from 40 kg to 35.9 kg (about 79 lb) net, to match Tonewinner's published specifications.

  • , Melodika Brown Sugar BSSC3300 review

    The review said this cable uses Melodika's Multi-Gauge Core. Melodika specifies the BSSC3300 as spiral LITZ with single-gauge strands (Melodika lists Multi-Gauge Core for other models in the range, such as the BSSC50), so that claim, its FAQ and its pro were removed and the construction corrected to Melodika's specification.

  • , HIFIMAN EF400 review

    Weight corrected from 3 kg to 3.08 kg, to match HIFIMAN's published specifications.

  • , SMSL PS100 review

    The claim that the PS100 is limited to 16-bit is withdrawn: SMSL specifies 24-bit/192 kHz over optical and coaxial and 44.1-48 kHz over USB, and rates the dynamic range at 96 dB. The con, the FAQ and the specifications section now say so; weight added from SMSL's specifications.

  • , HIFIMAN Svanar Wireless review

    LDAC's ceiling corrected from 24-bit/192 kHz to 24-bit/96 kHz, and the codec list corrected to LDAC, AAC and SBC, to match HIFIMAN's published specifications and owner's guide.

  • , HIFIMAN Sundara review

    Weight corrected from 372 g to 342 g and sensitivity from 94 to 92 dB/mW, to match HIFIMAN's published specifications.

  • , HIFIMAN HE-R9 review

    Impedance corrected from 32 to 60 ohms, to match HIFIMAN's published specifications; frequency response, weight and connector added from HIFIMAN's specifications.

  • , HIFIMAN Edition XS review

    Weight corrected from 400 g to 405 g, to match HIFIMAN's published specifications; impedance, sensitivity and frequency response added from HIFIMAN's specifications.

All 66 of Jakub's reviews carry a Checked stamp, the most recent from .

Spotted an error in one of Jakub's reviews? Report it; every report reaches the person who wrote the review. How the publication stays independent is on About, and how a byline works on Authors.

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