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1. Definitions

MKVS means The Master-Key Vocal System™, legally trading under the private limited company Hekker Bros. Ltd and subsidiaries or affiliates. The Master-Key Vocal System™ owned by Søren Sedit and Hekker Bros. Ltd. MKVS is the name of the vocal tuition and vocal coaching business specialized to deliver a one of a kind vocal technique development as it is advertised on and other various online platforms and Sites.

The Master-Key Vocal System™ is the trading name of
Hekker Bros. Ltd
71-75 Shelton Street
Covent Garden
London, England
Company number: 08549381 .

In these Terms and Conditions of Use, MKVS is sometimes referred to as “we,” “us,” or “our,” depending on the context.


Services means any products, services, content, features, technologies, or functions, and all related websites, applications and services offered to you by MKVS and its Sites. Services may include but are not limited to: vocal lessons, recording sessions, classes, vocal exams, seminars, free consultations workshops and master classes. In these Terms and Conditions of Use, Services is sometimes referred to as “service”, “services”, “session”, “sessions”, “booking”, “bookings”, “lesson” or “lessons”, ”training,” depending on the context.

Sites means the websites, mobile apps, official social media platforms, or other online properties through which MKVS offers the Services and which has posted or linked to this Terms and Conditions of Use.
Sites include but are not limited to , , .


User means an individual who uses the Services or accesses the Sites. Furthermore User means an individual who books and / or purchases any sessions, licenses or services offered and sold by MKVS. A User is both anyone who is currently utilizing the MKVS booking services and in completion of the training period to hold a license, as well as those who have booked sessions at MKVS or purchased from MKVS in the past and already holding a license issued by MKVS.
In these
erms and Conditions of Use, User is sometimes referred to as "Users", “customer”, “customers”, “client”, “clients”, "the Contractor", ”student”, “students”, “you”, “your”, “yours” depending on the context.

Account means a MKVS member account registered by a User on .

MKVS License means an official license issued by The Master-Key Vocal System to a User or Teacher. These MKVS Licenses are conditionally permitting their holders to use both intellectual and physical copyrighted properties of MKVS for the time period between the license has been issued and its expiration date or until MKVS revoking the license’s validity.
In these
erms and Conditions of Use, MKVS License is sometimes referred to as “license”, “licenses”, “Teacher license”, “Student license”, “any of our licenses”, “licensed” depending on the context.

Master Teacher means the head of teaching at MKVS, the author and co-owner of MKVS, namely Søren Sedit. In these Terms and Conditions of Use, Master Teacher is sometimes referred to as “SS”, "Søren Sedit" or “Soren Sedit” depending on the context.

Teacher means the tutor, teacher or vocal coach who represents MKVS, who is holding or used to hold a valid MKVS Teacher License in the past and who provides our services to our students provided that they are “actively” licensed. Actively licensed means that they have successfully renewed their Teacher License every year and it is still in a valid status. Teacher can be anyone who is currently engaged in business or who has been engaged in business with MKVS in the past.
In these
erms and Conditions of Use, Teacher is sometimes referred to as “teacher”, “teachers”, “our teacher”, “our teachers”, “tutor”, “tutors”, “vocal coach”, “vocal coaches” depending on the context.

Licensing period means the time period between the date the User purchased the MKVS License and the date when successfully passes the final exam at the end of the vocal and theory training, and the Master Teacher and MKVS issues the MKVS Certificate to the User. This period includes typically 16 vocal training and theory lessons about MKVS and lasts maximum one calendar year. In these Terms and Conditions of Use, licensing period is sometimes referred to as "learning period", "training period" or "pre-license period" depending on the context.

Paperwork means the physical documentations that all parties (MKVS, Master Teacher, User / Teacher) need to read, sign, authenticate with witnesses’ signatures and send MKVS’ copy back to MKVS by post immediately after it has been signed by all parties. In these Terms and Conditions of Use, paperwork literally means;
1, the
non-disclosure agreement (typical identification number of the document is MKVS NDA #0...)
2, the
student contract (typical identification number of a student contract is MKVS SLC #0...) or the teacher contract (typical identification number of a teacher contract is MKVS TLC #0...)

Data Controller means that MKVS determines the purposes and means of the processing of Personal Data.


Device Information means data that can be automatically collected from any device used to access the Sites or Services. Such information may include, but is not limited to,
your device type;
your device’s network connections;
your device’s name;
your device IP address;
information about your device’s web browser and internet connection you use to access the Site or Services;
Geolocation Information;
information about apps downloaded to your device;

and biometric data.

Geolocation Information means information that identifies, with reasonable specificity, your location by using, for instance, longitude and latitude coordinates obtained through GPS or Wi-Fi or cell site triangulation.

Personal Data means information that can be associated with an identified or directly or indirectly identifiable natural person. “Personal Data” can include, but is not limited to,
postal address (including billing and shipping addresses);
telephone number;
email address;
payment card number;
other financial account information;
account number;
date of birth;
and government-issued credentials (e.g., driver’s license number, national ID, passport number).

Process means any method or way that we handle Personal Data or sets of Personal Data, whether or not by automated means, such as collection, recording, organisation, structuring, storage, adaptation or alteration, retrieval, and consultation, disclosure by transmission, dissemination or otherwise making available, alignment or combination, restriction, erasure or destruction of Personal Data.


Technical Usage Data means information we collect from your phone, computer or other device that you use to access the Sites or Services. Technical Usage Data tells us how you use the Sites and Services, such as what you have searched for and viewed on the Sites and the way you use our Services, including your IP address, statistics regarding how pages are loaded or viewed, the websites you visited before coming to the Sites and other usage and browsing information collected through Cookies.


2. General Terms and Conditions of Use


a, Please note that by booking any of our sessions or Services, taking lessons, purchasing any of the MKVS Licenses or by making any other purchase from MKVS, both students and Teachers automatically accept and agree to the following terms and conditions.

The site is provided by Ltd and by accepting the following terms and conditions, you also automatically agree and accept their T&Cs that can be read on this link:


Please carefully read the following terms, policies and statements on the MKVS website before you make any purchase from MKVS. (Terms and Conditions of Use) (Trademarks) (Copyright Statement / Notice) (Privacy Statement) (Booking, Cancellation and Refund Policy) (Forum Policy) (Disclaimer) (Frequently Asked Questions)


Please note that you automatically understand, agree with and accept all above mentioned and also all paperwork (NDA and License Contracts) by clicking or ticking on “I agree” to the “MKVS terms and conditions” on Therefore you are stating that you are happy to sign the paperwork MKVS will send to your address after you have made the payment for an MKVS license.

We reserve the right, at any time, to modify the Services and/or this Terms and Conditions of Use and other policies mentioned above without prior notice. We recommend that you check these Terms of Service periodically to see if there have been any modifications. Modifications will become effective immediately upon being posted on the Site. Your continued use of the Services after modifications are posted will be considered an acceptance of the modified Terms and Conditions of Use.


b, MKVS offers the Services including but not limited to all vocal lessons, training sessions, consultations and vocal exams in English language. All Services provided by the Master Teacher (Søren Sedit) are also available in Danish upon request of the User. All MKVS related communications must be made in writing English, and preferably over email. Users, students, Teachers and Master Teacher must communicate with each other and with MKVS in writing English and over the following specific email addresses; (MKVS), (Master Teacher),

all current and future custom email addresses of Teachers (

Any MKVS related topic of written or verbal discussions and communications outside of these email accounts (such as Skype, Zoom, Google accounts, text messages, Facebook messenger, WhatsApp, personal or any other email addresses of Teachers, Master Teacher or MKVS, etc...) is strictly prohibited.


c, All documents, audio or visual material and other teaching methods released and shared by MKVS and / or the Teacher during a lesson or during any other Services and consultations (including advertising and marketing materials) are subject to our copyright and ​distribution. Copying or re-sharing any physical and intellectual properties and assets of MKVS without the prior permission of MKVS is strictly prohibited. Any sort of recording (audio or / and video) of any Services (including but not limited to lessons, web seminars, master classes and consultations) by Users or any third party without the prior permission and knowledge of MKVS is strictly prohibited.

MKVS reserves the right to use all media content (photos, audios, videos) that are recorded by MKVS, Teacher or by a third party during Services (including but not limited to lessons, web seminars, workshops, master classes and consultations) for educational, marketing and advertising purposes.

Please seek further information on this topic in the MKVS non-disclosure agreement and the MKVS license contracts.


d, MKVS reserves the right to change the Teacher assigned to you during the licensing period at any time, for any reason. When you purchase your MKVS license, you are purchasing Services provided by MKVS and not Services exclusively provided by the particular Teacher you have chosen. Therefore you can certainly choose your Teacher upon purchasing the MKVS Student License however MKVS cannot guarantee that the Services will always be provided by that particular Teacher.

Please seek further information on this topic in the MKVS license contracts.


e, MKVS Services, especially vocal lessons, sessions and webinars primarily provided to the User online, and primarily via Google Meet, Google Duo or Google Classroom online video chat / conference communication platforms.

These platforms are provided by Google and therefore neither the User, MKVS, the Teacher or the Master Teacher shall not be held responsible for connection problems and failures caused by these third party platforms that disrupt or delay the lessons.

In special circumstances, MKVS allows to change the platform of the Services to SKYPE ™ or Zoom ™, as long as;

  • both User and Teacher / Master Teacher agrees to the change of online platform,

  • MKVS has granted the permission to the change of online platform prior to the start of Services on the new platform.


f, Users are entitled to receive 16 lessons from a Teacher or the Master Teacher during the training period. Users are allowed to start the final exam before finishing all 16 lessons if both the Teacher and Master Teacher finds you prepared enough for the test. Also in case you need more lessons before the final exams or you do not pass the first test, MKVS provides additional maximum 8 lessons, therefore the total number of lessons the User is entitled to with an MKVS License is 24. If you do not pass the first test, a second exam will be offered to you. The User understands and agrees that to complete the licensing period and successfully pass the final exam the User has a maximum one calendar year (365 days) from the date of purchasing the MKVS license.

If for any reason this would take longer than one year, MKVS might allow to extend the licensing period with an extra few months. However in such cases both the User and Teacher must always consult with MKVS first. MKVS reserves the right to refuse to extend the licensing period and not to continue to provide Services to the User and not to issue a valid license to the User on a no refund basis if MKVS finds the User inactive, passive and incapable to finish the licensing period with a successful final exam.

g, *Free Online Consultations*
MKVS offers obligation-free online consultations to those who would like to know more about the MKVS Licensing and the potential & possibilities of being licensed by MKVS for free of charge via Skype, Zoom or Google Meet only. Anyone can book the free MKVS consultation but one individual can only participate in the consultation once. MKVS reserves the right to refuse or cancel the consultation with you if we think you already participated in one in the past or if you are or you were a User before.
Please remember, the consultation is
not an actual vocal lesson, the consultation is for introduction and informational purposes only. Under no circumstances any actual fact or sensitive information of MK will be exchanged with you during the session.

You can book a free MKVS consultation by writing an email to Master Teacher Søren Sedit on and asking for a free appointment.
Consultations are available only on specific days of the week and in limited times slots.

The length of the consultation is maximum 30 minutes.

h, When Users purchase an MKVS License, MKVS sends the “Starter package” to their address by post that includes two copies of the paperwork (NDA and Student / Teacher contract) signed by MKVS and its witnesses. Users can keep one of the copies for themselves, the other copies must be carefully read, understood, accepted and agreed to all terms of the paperwork by Users.

Furthermore, Users must;
fill in the first pages of the paperwork with the User’s personal information where it is required with all capitals
sign the last pages of the paperwork using a black inked pen
sign the User’s initials at the bottom of each page of the paperwork using a black inked pen
- make sure that the User’s
witness also fills in the Print name and Address sections with all capitals, and signs the last pages of the paperwork using a black inked pen
put one of the copies of the completed paperwork in a heavy duty / padded envelope (MKVS may provide this within the Starter package) and send it back by post to MKVS using the address that has been provided in the Starter package.

Users are responsible for sending the completed and signed paperwork back to MKVS as soon as possible. Users are also responsible for any postage cost that may be incurred by this process.
MKVS may reimburse your postage cost afterward, but it is not guaranteed and you need to check with MKVS first.
If you live or your postal address is in the
United Kingdom, Hungary or Bulgaria, MKVS may be able to provide you with pre-paid envelopes, therefore Users can post the paperwork back to MKVS for free of charge.

Users are also responsible for acquiring a person who is witnessing the User’s signatures on the paperwork and is also willing to sign the paperwork as witness of the User.
If User sends an inaccurate or incomplete paperwork to MKVS, MKVS reserves the right to postpone any further Services that are meant to be provided to the User until the correct and complete paperwork has arrived to MKVS and is in the possession of MKVS.



4. MKVS Student License Contract


5. MKVS Teacher License Contract

6. T&Cs that are relevant to Students only

Upgrading your Student License to Teacher License

Users both during and after the licensing period can upgrade their MKVS Student License to MKVS Teacher License. Downgrading from a Teacher License to a Student License is not possible.

Users can decide regarding the upgrade on their free will for any reason, however MKVS also reserves the right to prompt you to upgrade your MKVS Student License if we find out that you are using already or planning to use MKVS for personal and business purposes in the future, you gain your MKVS License for commercial, educational use and / or you are teaching or planning to teach the MKVS method to another User.

You can upgrade to MKVS Teacher License anytime provided that you are / were a student of the Master Teacher and you purchase “Upgrade to MKVS Teacher License V.1.” on .
Once the payment of the upgrade has been made, you will receive a few additional things from MKVS (Please note that you will not receive another full Starter package) and you can continue the training period lessons for Teacher license with Søren Sedit.

If you are / were a student of another MKVS Teacher, you can only upgrade to Teacher License once you have passed your exam for MKVS Student License. Once you receive your Student License and Student Certificate, only then you can purchase “Upgrade to MKVS Teacher License V.2.” on .
Once the payment of the upgrade has been made, you will receive a few additional things from MKVS (Please note that you will not receive another full Starter package) and you can start the training period lessons for Teacher license with Søren Sedit.

(In case of upgrading with V.2, MKVS provides maximum 12 lessons only to Users)

As the Teacher License training can be provided by the Master Teacher only, upgrading a Student License to a Teacher License is also only possible with the Master Teacher. Other MKVS Teachers can not train for a Teacher License.

Once you've taken the final Teacher License exam, you will hold the same MKVS Teacher License and Teacher Certificate with the same privileges and benefits as other Teachers who purchased the MKVS Teacher license straight away.

** Please note**
MKVS reserves the right to
decline the Student licensing and provide the training for Student license, if we find out that the User should have chosen the MKVS Teacher License.
No refund from any payment might have been made by this User will be issued and the User must upgrade to MKVS Teacher license immediately, only then can the User continue or start the licensing period for the MKVS Teacher License with the Master Teacher.

7. T&Cs that are relevant to Teachers only

a, Renew MKVS Teacher license to remain an actively licensed Teacher:


From the moment a Teacher receives the certificate with the MKVS Teacher License, Teacher have exactly one calendar year "active teacher" status. It means they have one year to enjoy the benefits of the license, after that Teachers will need to renew their license to keep the status active.

Teachers need to renew their license every year to get the continuous support from MKVS and so the Master Teacher can make sure that the Teacher's knowledge and teaching practices are matching the high standards MKVS dictates.

Please find further definition on "actively licensed" Teacher on section 1. Definitions, under the term: Teacher.

When the MKVS Teacher license is about to expire, MKVS will send Teachers a reminder email and will bring their attention to their options, including renewing the license.
If a Teacher’s MKVS Teacher license
expires and the Teacher do not renew the license within 5 days from the expiry date by purchasing “Renew your MKVS Teacher License” on, that Teacher will automatically become inactive and will become ineligible teaching MKVS student trainees with immediate effect. If the Teacher is actively licensed and currently training a student or more multiple students, and the Teacher’s MKVS Teacher license expires within the student’s training period, all of those students will be taken away from the Teacher and the student or students will continue to train with another Teacher or with the Master Teacher delegated by MKVS.


If a Teacher renews the Teacher license, everything stays the same for the Teacher as per the teacher contract and in this Terms and Conditions of Use.
Additionally Teachers will receive
6 free lessons with the Master Teacher that they can book within the one calendar year period to keep them up to date with the MKVS.

If Teachers do not renew their Teacher license, after 5 days of the expiration date of their MKVS Teacher license, Teachers can NOT teach the MKVS method within, or outside the MKVS system.
In greater detail, the custom MKVS email accounts (Google accounts), all social media, Skype, Zoom accounts or any other online or physical accounts that are connected to their custom MKVS email accounts and teacher user accounts on of these “inactive Teachers” are immediately
revoked and deactivated.
This basically means that future MKVS
students can not book MKVS Student license training sessions with inactive Teachers. Furthermore these Teacher’s pictures and details will be rearranged to the bottom of the “Teachers” page on the MKVS website, and they will be stamped with the “inactive” label.
Inactive Teachers will not receive future updates from MKVS, they will no longer have any access to the MKVS papers, or any future publications of MKVS.
An inactive Teacher’s teacher
contract is not terminated by MKVS, therefore these Teachers can still use MKVS just like a MKVS Student license, for personal use only. However inactive Teachers can not teach the MKVS method to anyone outside the MKVS system or to anyone who does not initially go through official licensing at MKVS.
If an inactive Teacher has not renewed the Teacher license and after a period of time (can be months or even a couple of years) he or she wants to be an active Teacher again, he or she can naturally purchase the renewal license anytime and continue with full benefits of the MKVS.

b, Invoicing to MKVS, Payments to Teachers:

MKVS pays tuition fee to Teachers after each lesson that has been given by the Teacher to students. Further terms and conditions of this self employment based work that Teachers do for MKVS can be found in the teacher contract, Paragraph 7.b, and 7.c.
Teachers are self employed contractors and Teachers
must invoice the tuition fee to MKVS according to the following schedule, instructions and guidelines, unless otherwise instructed by MKVS in writing prior to the invoicing deadlines;


- The Teacher is only allowed to invoice tuition fees to MKVS after each successfully finished training lessons given to a student within the particular invoicing period.
- The amount of the tuition fee is typically
£275.00 per lesson, but in every instance it is indicated in the teacher contract, and the Teacher must follow its guidelines regarding the amount of the tuition fee unless otherwise instructed by MKVS. Also MKVS reserves the right to change the amount of the tuition fee in exceptional circumstances.
- Teacher must
indicate on all invoices the name of the student for each lesson that has been given by the Teacher and that is invoiced to MKVS.
- The
invoicing period always must be from the first day, to the last day of each calendar month. As the MKVS System and booking site ( operates on Greenwich Mean Time (GMT) or British Summer Time (BST) depending on the time of the year, therefore only, and all those lessons that has been finished by 23:59 GMT/BST of the last day of the month will count within the invoicing period. Teachers should always seek advice from MKVS regarding uncertainties in this topic, prior to finalising invoices sent to MKVS.
- Teachers must send the tuition fee invoices for a particular invoicing period earliest on the 1st day and latest on the 10th day of the following calendar month to MKVS. Teachers
must use a personal or other business email address where they send their invoice from and should not use their MKVS custom email account ( Teachers must always issue their tuition fee invoices to:

Hekker Bros. Ltd
71-75 Shelton Street
Covent Garden
London, England

Company number: 08549381

and email it to , unless otherwise instructed by MKVS.
- Teachers must issue their invoices with a “
14 days from date of invoice” due date where the date of invoice can not be earlier than the 1st day of the calendar month following the invoicing period.
MKVS will clear Teacher’s invoices
within the first 14 days of the calendar month following the invoicing period provided that the Teacher and Users has followed all terms and conditions and guidelines of MKVS. However MKVS does not take responsibility for late payments in case the Teacher’s invoice has not been sent in time, or payment delays due to bank holidays or international payments.
- Teacher is fully
responsible for the correct and valid filling of the invoices issued to MKVS. MKVS does not take responsibility for missing, “bounced back” and delayed payments due to the incorrect filling (e.g. mistakes in bank account numbers, spelling mistakes in account holder’s name, wrong total amount, or due date) by the Teacher on the tuition fee invoices. If the tuition fee invoice is incorrect MKVS will always notify the Teacher and ask for correction, and MKVS reserves the right to not clear the Teacher's invoice until they are corrected and re-sent to MKVS.
- Teacher must indicate on all invoices the Teacher is fully responsible for all
taxes and other liabilities occur from the payments made by MKVS to clear the invoice.

Both MKVS and Teachers agree that the only acceptable payment method of clearing invoices is bank transfer.
MKVS only accepts invoices from Teachers that
display GBP currency as the total due amount and payment method is local bank transfer within the UK (BACS, CHAPS, and Faster Payments).

In special circumstances Teachers may request to transfer the tuition fee to an international bank account or / and in a currency other than GBP. In such cases any MKVS’ additional fees and charges that may occur from making international payments into foreign bank accounts will be deducted from the total amount of the invoice.
MKVS may offer solutions for Teachers to access a local GBP bank account, and alternative solutions with small transaction fees but MKVS can not guarantee any of these all the time. In any case other than a local bank transfer to a UK bank account, Teacher must always
indicate where he or she requests the payment to be made clearly on the tuition fee invoice, and in every case Teachers are fully responsible for additional fees and charges that may occur due to the non local bank transfer.
As a reminder, Teachers are self employed and Teachers are fully responsible for their own Tax and National Insurance may occur from invoicing MKVS.

c, Teacher's custom MKVS email account and system profile

MKVS will not create, issue and give access to the User to the Teacher profile account in the MKVS booking system and any other accounts that must be registered to the organisation of MKVS (Skype, Zoom, social media accounts of the Teacher) until the licensing period has not been ended with a successful final exam of the Teacher License.

However the custom MKVS email account ( of the User will be created and access will be given to the User to it as soon as MKVS receives the paperwork signed by all parties and the first 14 days period from the purchase of the MKVS Teacher license has also passed.

User must always and only use the custom MKVS email account during and after the licensing period for MKVS related communications and MKVS Services.

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Should you have any questions, enquiries or concerns, you can reach us on any of the following:

To book an appointment or get MKVS license:


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General enquiries:



Master Teacher & Author of MKVS:


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