Get Master Private Key from BIP39 Seed I have BIP39 Seed:

5b56c417303faa3fcba7e57400e120a0ca83ec5a4fc9ffba757fbe63fbd77a89a1a3be4c67196f57c39a88b76373733891bfaba16ed27a813ceed498804c0570


I want to get Master private Key 

Then I Have to use HMAC-SHA512, I can use this site, which secret I have to add ? I don't have any secret, for test  I choose "mnemonic", the same constant that I use to generate BIP39seed (is it correct? )

the result is: 


  9744d0d7e168f725b6cc36a73c24dfc91bd6d80bf5a6871ad2c6c0b854e4e281b74049c41d25f0b338b3fc9b053b87b95636c3c94c31f37458fe98a09a4a94c9


and I can get

left 256 bits  =&gt; 9744d0d7e168f725b6cc36a73c24dfc91bd6d80bf5a6871ad2c6c0b854e4e281
right 256 bits  =&gt; b74049c41d25f0b338b3fc9b053b87b95636c3c94c31f37458fe98a09a4a94c9


And I can Get master private key in this way?

PKM = bx ec-to-wif 9744d0d7e168f725b6cc36a73c24dfc91bd6d80bf5a6871ad2c6c0b854e4e281



  result:
  L2Hku6wzwvWnHAct8TmtfvviE4QXBTXtZrae2buXwjq5mRG4doF2


but this result is not in https://iancoleman.io/bip39/ If I import my mnemonic phrase 


  (army van defense carry jealous true garbage claim echo media make crunch)
Here are the mechanics for "Mastering Bitcoin" Creating an HD Wallet from the Seed using  bitcoin-explorer and this Python HMAC command.  

Root Seed:

% echo "army van defense carry jealous true garbage claim echo media make crunch" | bx mnemonic-to-seed -p ""

5b56c417303faa3fcba7e57400e120a0ca83ec5a4fc9ffba757fbe63fbd77a89a1a3be4c67196f57c39a88b76373733891bfaba16ed27a813ceed498804c0570

Master Private Key:

% echo 5b56c417303faa3fcba7e57400e120a0ca83ec5a4fc9ffba757fbe63fbd77a89a1a3be4c67196f57c39a88b76373733891bfaba16ed27a813ceed498804c0570 | bx base16-decode | hmac --algorithm sha512 --key "Bitcoin seed" - | cut -c 1-64

b2a0d576b828b537688b561f2cfa8dac3602d54c62bde619ad5331e6c235ee26   

Master Public Key:

% echo 5b56c417303faa3fcba7e57400e120a0ca83ec5a4fc9ffba757fbe63fbd77a89a1a3be4c67196f57c39a88b76373733891bfaba16ed27a813ceed498804c0570 | bx base16-decode | hmac --algorithm sha512 --key "Bitcoin seed" - | cut -c 1-64 | bx ec-to-public

03ca72b45eede592f059b7eaf3da13eb7d8d15aa472b6f79f74820bb22ff596186

Chain Code:

% echo 5b56c417303faa3fcba7e57400e120a0ca83ec5a4fc9ffba757fbe63fbd77a89a1a3be4c67196f57c39a88b76373733891bfaba16ed27a813ceed498804c0570 | bx base16-decode | hmac --algorithm sha512 --key "Bitcoin seed" - | cut -c 65-128

b70d675323c40ec461e0a6af603b1f135fb2af9ae753eeff18922732a73b0f05