The SPL (Sound Pressure Level) heat map shows how sound distributes across your room. Think of it like a weather map, but for sound intensity instead of temperature.

Color scale

Good vs. bad heat maps

Hot spots (red areas near walls)

Red zones near walls mean sound is reflecting and building up. This causes some areas to sound unnaturally loud.

Cold spots (blue areas)

Blue zones are areas that don't receive enough sound energy. People sitting here will struggle to hear clearly.

Why uniform coverage matters

The best listening experience comes from even sound coverage. A smooth, consistent color across your seating area means your speakers are well-placed. Big color differences mean some listeners will hear too much bass or treble while others hear too little.

RT60 measures how long it takes for sound to fade away in your room — specifically, the time for sound to drop by 60 decibels after the source stops.

Everyday analogy

Clap your hands in your bathroom — you'll hear the sound ring and echo. Now clap in your bedroom — the sound dies quickly. That's the difference between high and low RT60. Bathrooms have hard, reflective surfaces (tile, glass) that keep sound bouncing. Bedrooms have soft surfaces (carpet, bedding, curtains) that absorb it.

Ideal RT60 by room purpose

RT60 too high? (echoey room)

How to reduce RT60:

• Add thick curtains or drapes
• Install carpet or large area rugs
• Use upholstered furniture
• Mount acoustic panels on walls
• Add bookshelves filled with books

RT60 too low? (dead room)

How to increase RT60:

• Remove some soft furnishings
• Replace carpet with hard flooring
• Use reflective materials (wood panels, glass)
• Reduce the number of acoustic panels

Critical distance is the point in your room where the direct sound from the speaker and the reflected (reverberant) sound are equally loud. Beyond this distance, you hear more room echo than actual speaker output.

Why it matters

If your listening position is beyond the critical distance, you're essentially hearing the room more than your speakers. This makes audio muddy and unclear. For the best experience, sit within 70% of the critical distance.

How to increase critical distance

• Add more absorption (panels, carpet, curtains)
• Use directional speakers instead of omnidirectional ones
• Reduce room volume if possible (lower ceiling, partitions)

Absorption measures how much sound energy surfaces soak up instead of reflecting back. It's measured in sabins — named after acoustics pioneer Wallace Sabine. Higher absorption means less echo.

How materials affect sound

Every surface in your room either absorbs or reflects sound. Hard, smooth surfaces (concrete, glass, tile) reflect almost all sound energy. Soft, porous materials (carpet, curtains, foam) absorb it.

Material absorption coefficients

Coefficient ranges from 0 (total reflection) to 1 (total absorption):

Most effective improvements (ranked)

The calculator gives you speaker coordinates as (x, y) values measured in meters or feet. Here's how to translate those numbers into real-world placement.

Understanding the coordinate system

Coordinates are measured from the top-left corner of your room (as viewed from above). x is the distance from the left wall, and y is the distance from the front wall.

Step-by-step: placing your speakers

Speaker height

Place speakers so the tweeter (high-frequency driver) is at ear level when you're seated. For most people, this is about 1.0–1.2 meters (3.3–3.9 feet) from the floor.

The “sweet spot”

The sweet spot is the position where sound from both speakers arrives at your ears with perfect timing and balance. In a stereo setup, it's typically at the point of an equilateral triangle formed with your two speakers. The heat map's green center usually shows exactly where this is.

“I have a small living room”

Small rooms tend to have strong bass buildup in corners and short critical distances. Place speakers away from walls (at least 30 cm / 1 ft) and use the stereo configuration. Add a rug and curtains to control reflections without making the room feel dead.

“My church sounds echoey”

Churches often have stone walls, high ceilings, and large volumes — resulting in very high RT60. Solutions include:

• Hang heavy fabric banners from walls and balconies
• Install acoustic panels behind the speaking area
• Use focused, directional speaker systems (column speakers)
• Add padded pews or seat cushions for congregation seating
• Consider a distributed speaker system for even coverage

“I want a home cinema setup”

For 5.1 surround, aim for an RT60 of 0.3–0.5 seconds. Key placements:

• Center: Directly below or above the screen, at ear level
• Front L/R: At 22–30° angles from the center listening position
• Surround L/R: At 90–110° to the sides, slightly above ear level
• Subwoofer: Corner placement for maximum bass, but try different spots to avoid boominess

“My room sounds dead”

If your RT60 is very low (under 0.2s), the room has too much absorption. This happens in heavily treated studios or rooms with lots of soft furnishings. Remove some acoustic treatment, swap carpet for hard flooring in some areas, or add reflective surfaces like a wooden coffee table.