1. Summary

This document describes the "studio board" computer systems in the KPFZ studio.

It is not concerned with other computers like the Streaming system and the RF Control computer.

The system is:

  • KTR/CH17 : NEW Lenovo computer, with a 5-year on-site warranty.
  • KBO/CH15 and KPS Computers: New Lenovo computers, same model but with 8G RAM and CD's
  • Audio components: (2x2 USB audio modules and cables) from Sweetwater (2 year warranty)
  • Various accessories, including USB hubs, camera, monitor

Note : this document was originally the specification, and is being updated to reflect the "as-built" configuration.

2. Computers

2.1. KTR/CH17 Computer (Record/Replay)

The old system died, and one of the new systems was used to replace it

  • "KTR CH17 (Record/Replay)" computer replaced the old system, using Total Recorder in the "old way". It allows remote control through Teamviewer.
  • The computer used was the "KPS" computer, which is intended for (Andy's) Production Studio.
  • The monitor and USB hub intended for the KTR computer need to be swapped out
  • Teamview provides an "upload" mechanism for pre-recorded shows.

Plans to replace the completely manual "Total Recorder" method with a script-based method have been shelved.

2.2. KBO/CH15 Computer (Board Operator/Remote)

Note: this was originally supposed to be connected to Channel 18, but Ch 15 "External" is being used. Some documentation (particularly the diagrams) may refer to CH18.
  • "Board Operator" (KBO) Computer", for playing off the web (music files, zoom ....)
  • Connect a KPFZ Zoom meeting with the studio board, so callers on 263-3435 can participate. This will also allow remote reporting from a cell phone or a laptop.
  • Allow a "Remote Board Operator" (RBO) to connect (through a Zoom meeting) to the studio board when it is unattended.
  • This will connect to the studio board through Channel 15 (EXTERNAL).
  • RemotePC software will be used to connect to it (Cheaper than Teamviewer)

2.3. KPS Computer (Andy/Production Studio)

John Saare is now responsible for this computer.

The "AOS" (Andy Office Studio) computer has similar capabilities to the KBO Computer

  • Additional RAM is needed (16G?), but has not been ordered.
  • An external Disk Drive might be needed, but not yet ordered.
  • It could connect to the mixer board in Andy's office.

The actual computer for this is presently serving as the KTR computer. They need to be swapped.

3. Studio Configuration

3.1. KTR/CH17 Computer

This computer is maintained by John Saare.

Its main functions are to record and replay shows using Total Recorder.

Plan 0

  • The studio board output (A) goes the distribution amplifier and then to the transmitter system (B), and the streaming computer (C).
  • The distribution amplifier output also goes (D) to the main "CH17" (Record/Replay)" computer (E), where it can be recorded by Total Recorder on a local disk (F)
  • The KTR/CH17 computer (E) also replays files via Total Recorder into Channel 17 (G) -- which is potted up for REPLAYS.
  • The KTR/CH17 computer (E) has a monitor, keyboard in the studio for direct access.
  • The KTR/CH17 (E) computer is also accessible from the web with Teamviewer. This is used to:
    • Upload (H) pre-recorded program files
    • Control (I): Access the login screen to set up the system, for example to edit the Total Recorder scheduler.
  • The board operator / host / guest can bring in a portable device (O), connecting to the internet via wifi or LAN (P), and feeding into the "MP3" input (Q)

3.2. KBO/CH15 - Board Operator computer

This computer is maintained by Alan Fletcher.

A KBO" (Board Operator) Computer (K) is connected to Channel 15 (which is POTTED UP when needed). In some documents this will be called the CH18 computer.

Plan 1

The KBO computer can be used to :
  • Play off a USB stick or the web. (L)
  • Host or Join a Zoom meeting (J): the Studio Board and the Zoom meeting are merged, so callers to the studio line can participate fully in the Zoom meeting. (L)
  • Connect a remote Zoom meeting (J) when the studio is unattended.
  • Access the KTR/CH17 computer for control purposes. (M)
  • Act as a backup for the CH17 Record/Replay capability. (D,G) ??

Note that a headphone/mic (N) is needed if the studio board is NOT connected to a zoom meeting. For example, the Studio Host may wish to talk to the Zoom participants before the show goes on air.

Board MONO2 "Mix Minus"

3.3. KBO MONO2 "Mix Minus" Connection

At the time of writing the KBO computer gets a signal from the board from the Distribution Amplifer (by splitting the signal to the Stream Computer).

When joining a Zoom meeting the output from Zoom goes into the studio board on CH 15, but this signal comes right back from the Distribution Amplifier with a potential for Echo.

If I allow Zoom to apply all its algorithms to the signal -- particularly Zoom Echo Cancellation -- then the resultant quality is reasonable (about as good as a phone line, though it occasionally produces a 'squirrely chirp'.)

If the zoom invitation is set up incorrectly to allow "Original Sound", and if ANY participant turns off Echo suppression then the entire meeting is ruined unitl either:

  • Channel 15 has to be potted down, and listeners will no longer hear the zoom meeting (This is quickest, and is thus the recemmended solution).
  • The KBO Board Operator sets the Zoom microphone to MUTE, and the Zoom meeting can no longer hear what's happening in the studio.

  • Also, there is always the danger that Zoom may change something (or that we might switch to a different system entirely) and that this Echo would make the system unusable.

    The solution is to do a "Mix Minus" on the External (Ch 15) input to the board (similar to what is done on the phone lines).  Then the Zoom sound will go onto the board and the transmitter, but it won't go back into the computer. Then I can set Zoom to "Original Sound Stereo" which is "FM" quality.  

    The MONO2 output of the studio board is not being used.

    Depending on some tests, the MONO2 output could either go directly to the USB Audio Card, or through an Amplifier (as is presently done).

    The Board Settings will be as follows:

    B1 :  For every channel except CH15, MONO2 switch is DOWN.

    B2:  For CH15 MONO2 switch is UP

    B3: MONO1 for phones is unchanged (UP for the two phone lines).

    B4: AUDITION and PROGRAM are unchanged (DOWN for all channels)

    Thus Zoom will hear everything that happens on the board, including mics, CD's and telephones. But it will no longer have the echo-producing feedback from itself.


    3.4. KPS (Andy / Production Studio)

    The KPS (Andy Production Studio) is essentially the same as the KTR Computer, except that it could connect to the mixer in his office.

    Plan 2

    This computer can be used to control the KTR/CH17 computer, or to act as a second broadcast computer either through a Zoom meeting on the SBO computer -- OR hard-wired to the studio board.

    3.5. Archive Storage

    This is an add-on to the previous plans. Shelved.

    The local disks on computers KTR/CH17, KBO and KPS will be supplemented by a large (eg 8TB) disk accessed through the network.

    The main advantage is that each computer needs only limited functionality. For instance, it might need only 8GB ram, a small (500GB) drive, and a slow processor (Speed kills!).
    They will only have a minimum disk drive for the operating system and temporary files.

    Most storage (recorded .WAV files) will be on a central network drive, which is mounted as a drive on every computer. I recommend a stand-alone NAS (Network Attached Storage) unit, with an error-tolerant RAID drive. Alternatively, a USB drive can be mounted on one of them (eg CH17), and accessed through the network.

    4. Remote Configuration

    4.1. Hardware

    We are trying to support both Windows and Apple Mac computers.

    I general it is presumed that you will have "reasonable" interconnect connections. For example, Mediacom has 10MB upload speeds. WiFi is unreliable, so you should use a LAN connection to your modem. Satellite connections (Hughes etc) will NOT work.

    The minimum equipment for Windows is 7 (or above), 8G RAM, and USB-2 ports.

    The performance of Chromebooks and Tablets is unknown (in LCTC they didn't work for video -- might be OK for audio only).

    Cell phones will not be supported for hosting, but can be used to dial in to a Zoom meeting.

    4.2. Audio

    You should get a good quality microphone (probably USB). You don't need Hi Fi headsets.

    4.3. Uploads to the Studio

    At present John Saare is handling uploads manually.

    There are two main options here:
    • Connect to the studio KTR/CH17 computer via Teamviewer and use the Upload mode.
    • Upload a file to the "web" (Google Drive,iCloud....). Then TotalRecorder can download it automatically at a set time, and play it on schedule. (File names are fixed)..

    4.4. Live Connection to the Studio

    • Do your show in Zoom (you can play music etc with "share screen/sound") -- you can set up the meeting either on your computer (Pro account), or from the studio computer (KPFZ Pro account).
    • If a board operator is present in the studio, then the Studio Board and Zoom meeting can be merged, and you can take phone calls on the studio line
    • If a board operator is NOT present in the studio, then you can connect to the board remotely (to the KBO computer).
    • Guests can join zoom by computer or phone.
    • We are investigating ways of connecting a local phone to zoom.

    5. Implementation

    5.1. Specifications

    5.1.1. Audio

    Note: I proposed storing sound files in compressed FLAC. But the new system had been set up using 20kZ WAV (Which I regard as inappropriate).

    Audio will be based on "CD" standard 44.1kHZ/16 bit FLAC

    A 2x2 (Stereo Input/Output adaptor) to connect computers to the Studio Board.

    Archive storage will also be stored as FLAC

    Uploaded / Old WAV archive files (eg for replays) will be converted to FLAC automatically.

    5.1.2. Computer Sizing

    I have operated my prototype system with the planned programs.

    Hardly any CPU is used. RAM peaks at about 3GB -- to give lots of "head room" I have specified 4GB for KTR/CH17 (which only does one job), 8 GB for the KBO and 16-32 (8 + add-on) for the KPS systems.

    The Lenovo computers have 250G(?) as the local disk size.

    Additional Disks could be USB or NAS.

    5.1.3. LAN and Storage

    The expected throughput for 44.1kHZ stereo is about 2 mbps (million bits per second) for each path (record, and remote/replay).

    Although 100MB connections are adequate, we may as well use Gigabit switches.

    Note: the following is for 44k WAV. FLAC would be about half this.

    A 1-hour recorded .WAV file is about 300MB (0.3 GB). We can thus store about 3000 files per TB. If 10 hrs/day are recorded/pre-recorded, we use roughly 1 TB/year (rounding wildly!).

    We should therefore preserve our archives in either a lossless FLAC) format.

    While SSD drives are becoming popular, they "wear out" after a large number of writes, and are still more expensive. I therefore prefer Hard drives.

    5.1.4. Windows 10 Pro

    Windows 10 Pro has some essential features, like Remote Desktop and a Linux subsystem (which we may need for scripting), and better user management.

    5.2. Implementation Prototype

    I have set up a (new refurbished) Lenovo M92 desktop as an initial CH17 computer (16G Ram/1T Hard Drive, DVD, Windows 10 Pro). I have tested stereo 2x2 connections (Behringer UCA202) to my own mixer (Yamaha). I have installed and tested Teamviewer, TotalRecorder Pro, Audacity and Zoom.

    I have set up my Lenovo laptop as a "KBO" (Remote Board Operator) SYSTEM.

    5.3. Implementation Plan

    Current Status
    • The KPS computer was used to replace the dead Total Recorder computer.
    • The KTR computer is in the office, set up as in the original specification
    • The KBO computer is set up in the studio and is partly connected to the sound board.

    Short Term Plans

    • Change the layout of the KBO computer (John Saare).
    • Swap the KTR and KPS computers.
    • Set up the KPS computer in Andy's Office

    Possible Long Term Plans

    These are shelved.

    • Review the specification for a semi-automated way of handling Total Recorder, and the prototype which implemented most of the features
    • Complete the new Total Recorder / Script system

    6. Unresolved Issues

    For Andy's board we could run a line from the board headset output.

    7. Operational Comments