Category Archives: Design

The last meter

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“The last meter” refers to the final connection between an audio device, such as a microphone, headphones, or speakers, and the larger sound system or network. Just as “the last mile” in telecommunications represents the crucial final stretch that delivers service to the end user, “the last meter” in audio engineering highlights the importance of the final cable or wire, which directly impacts the quality and reliability of the sound being transmitted. Despite its short length, this connection is critical for ensuring the integrity of the overall sound system.

The “asymptote of despair”

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“if we plot progress versus time it should be pretty much linear.  We are currently right about here  approaching the danger zone between works and done and those two things are not the same we have to be very careful not to get sidetracked at The Works
boundary and end up over here on the Asymptote of Despair where time goes to
infinity and we never quite finish our project”

python: maps Reaper DAW mixer volume and mute and solo to GPIO

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import pythoncom
import reapy
import RPi.GPIO as GPIO

# Set up the GPIO pins
GPIO.setmode(GPIO.BCM)
GPIO.setup(17, GPIO.OUT) # Volume pin
GPIO.setup(27, GPIO.OUT) # Mute pin
GPIO.setup(22, GPIO.OUT) # Solo pin

def set_track_volume(track, volume):
track.volume = volume
if volume > 0.5:
GPIO.output(17, GPIO.HIGH)
else:
GPIO.output(17, GPIO.LOW)

def set_track_mute(track, mute):
track.mute = mute
if mute:
GPIO.output(27, GPIO.HIGH)
else:
GPIO.output(27, GPIO.LOW)

def set_track_solo(track, solo):
track.solo = solo
if solo:
GPIO.output(22, GPIO.HIGH)
else:
GPIO.output(22, GPIO.LOW)

# Create a function to map Reaper tracks to GPIO pins
def map_track(track):
# Connect to Reaper
reapy.connect()
# Get the track from Reaper
track = reapy.Track(track)
# Set the track’s volume, mute, and solo status
set_track_volume(track, track.volume)
set_track_mute(track, track.mute)
set_track_solo(track, track.solo)
# Disconnect from Reaper
reapy.disconnect()

# Map Reaper track 1 to GPIO pins
map_track(1)

# Clean up the GPIO pins
GPIO.cleanup()

Metric Frame Rates: Banishing the Bizarre

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Metric Frame Rates: Banishing the Bizarre

In a digital world governed by binary precision, there is a ghost in the machine. It appears in the settings menus of our cameras and the export windows of our editing software. It is the spectral presence of fractional math: 23.976, 29.97, and 59.94.

These numbers are messy. They are relics. It is time we fully embraced a concept that brings sanity back to video: Metric Frame Rates.

Defining the Metric Frame Standard

What are Metric Frame Rates? They are the clean, integer-based measurements of time that align perfectly with the way we count seconds. They are the logical progression of temporal resolution:

* 25 fps: The cinematic baseline.

* 50 fps: The standard for smooth, lucid motion.

* 100 fps: High precision and clarity.

* 200 fps: Extreme fluidity and slow-motion capability.

Unlike the fractional legacy standards, these rates—25, 50, 100, and 200—do not require a calculator to determine how many frames exist in an hour of footage. They are absolute.

The NTSC Hangover: Where the “Weird” Came From

To understand the beauty of Metric Frame Rates, you have to look at the chaos they replace.

For decades, North America and parts of Asia have been stuck with the “NTSC” standard. Originally, black and white television ran at a clean 30 frames per second. But when engineers added color in the 1950s, they hit a snag: the color signal interfered with the audio signal.

Their solution? Slow the video down by exactly 0.1%.

Suddenly, 30 fps became 29.97 fps. 60 fields per second became 59.94. Cinema’s 24 fps was slowed to 23.976.

This “fractional frame rate” created a nightmare for editors and engineers. Timecode became a headache (Drop-Frame vs. Non-Drop Frame). Audio drifted out of sync over long durations. We have been carrying this baggage for over half a century, long after the analog cathode-ray tubes that required it were thrown into landfills.

The Elegance of the Metric System

Metric Frame Rates (rooted historically in the PAL/SECAM regions and 50Hz power grids) bypassed this absurdity. They stuck to the integers.

1. The Mathematical Harmony

Metric rates scale perfectly.

* 25 fits into 50 exactly twice.

* 50 fits into 100 exactly twice.

* 100 fits into 200 exactly twice.

This base-2 geometric progression makes frame-rate conversion, math, and compression algorithms significantly more efficient. If you shoot at 100 fps and want to slow it down to 25 fps, the math is flawless: play every frame for 4x slow motion. No “pulldown” patterns, no jitter, no ghost frames.

2. 25 fps: The Aesthetic Sweet Spot

While Hollywood clings to 24 (or the dreaded 23.976), 25 fps offers a nearly identical aesthetic experience with a slightly higher temporal resolution. It retains the “dreamlike” quality of film without the fractional headache.

3. 50 fps: The Reality Standard

50 frames per second is the metric answer to the “soap opera effect,” but used correctly, it provides the “being there” feeling required for news, sports, and documentation. It captures reality with fluid precision, free from the flicker of lower rates.

4. 100 and 200 fps: The Future of Clarity

As we push into high-refresh-rate displays (120Hz, 144Hz, 240Hz), Metric Frame Rates like 100 and 200 are becoming vital. They offer a hyper-real smoothness that 29.97 can never achieve. Furthermore, 100 fps serves as the perfect “universal donor” for slow motion—fast enough to capture high-speed action, but mathematically simple enough to conform down to 50 or 25 for delivery

We no longer live in an analog world of interfering radio frequencies. We live in a digital world of absolute values.

There is no technical reason for a modern digital creator to be forced to use 29.97 unless they are broadcasting to legacy television networks. For the rest of us—creating for the web, for streaming, and for the future—it is time to reject the bizarre numbers of the past.

It is time to standardize on the clean, logical, and precise integers of 25, 50, 100, and 200.

AUDIOVISUAL CONDUIT

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AUDIOVISUAL CONDUIT/ELECTRICAL NOTES

  1. The electrical contractor shall provide an AC power system for the audiovisual system. The AC power system may include isolation transformers, breaker panels, and distribution as noted. Refer to electrical drawings.
  2. Each circuit shall be wired as a 3-wire single phase 120 volt, with a separate hot, neutral, and ground conductor for receptacle.
  3. The electrical contractor shall provide and install conduit and all other enclosures, as called out in the audiovisual device/equipment drawings unless explicitly noted otherwise. Conduit shall comply with NEC requirements for conduit installation. Cross reference and coordinate with the electrical drawings.
  4. All conduit shown is for audiovisual system signal cable and is not related to any conduit for AC power. Conduit quantities and sizes are specified based on the system requirements. Do not combine multiple parallel runs into larger conduits.
  5. The conduit paths of the sound, communication and video systems should not be routed near power transformers, SCR dimmers, power control equipment, heavy current switchgear, fluorescent ballasts, motors or any other equipment that may be a source of interference.
  6. All interior junction boxes shall be NEMA 1 rated unless otherwise specified and shall be provided with covers by the electrical contractor.
  7. All conduit connections shall be furnished with nylon bushings to prevent damage to cables from burred or unevenly cut conduit.
  8. All junction boxes are to be given a unique identifying number that shall be legibly written on the inside cover with permanent, non-fading, weatherproof ink.
  9. Keep 90° bends to a minimum. The conduit system shall not have more than three 90° bends or their equivalent between pull boxes.
  10. All conduit runs in excess of 100 feet shall have intermediate junction boxes every 100 feet or three bends, whichever comes first.
  11. All audio/visual system related junction boxes shall remain accessible at all times.
  12. Electrical contractor shall provide nylon pull strings in all conduits.
  13. Completed floor pocket installation must be installed flush with finished floor surface. Coordinate installation with the architectural drawings.
  14. Conduits must enter the floor pocket back box thru the bottom of the lower 2½ inches of the side walls.
  15. Provide adequate cover and bracing during concrete pouring, to prevent leakage and/or collapse of the back box. Pour concrete completely around the back box.
  16. No flex conduit is to be used in the audiovisual system unless otherwise noted.
  17. All conduits carrying audiovisual signals are not to be run parallel to power conduits if the spacing exceeds 20 feet.
  18. Conduit fill shall not exceed 40% unless otherwise noted.
  19. Insulate all conduits and enclosures from incoming conduits.
  20. All conduits shall be securely fastened to building structure every 10 feet and within 3 feet of each box.
  21. All conduits for audiovisual system shall be at least 3/4-inch trade size unless otherwise noted.
  22. All conduits shall be reamed and bushed at all ends.
  23. Electrical contractor shall refer to electrical drawings for all 120VAC conduit sizing.
  24. Electrical contractor shall refer to other drawings for non-audio/visual system related electrical information for these areas. Audio/visual system drawings do not contain all room electrical requirements.
  25. The electrical contractor shall install and wire all high voltage devices.
  26. All power circuits shall be 120VAC, 20 AMP dedicated circuits unless otherwise noted.
  27. 120VAC power to the equipment racks shall be terminated inside the racks to audio/visual system subcontractor-supplied isolated ground plugmold plugstrips or isolated ground quad convenience outlets.
  28. Conduit will be required between any and all loudspeakers unless the loudspeakers are associated with an accessible ceiling plenum.
  29. All cabling installed and free-run above finished ceiling shall be supported with J-hook cable management system. Coordinate any CAT5e/CAT6 cabling colors with data/voice contractor. No red jacketed cables are permitted.
  30. The general contractor shall be responsible for final coordination of all installation and finish requirements within items of millwork or casework.