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Dedicated room · 20 × 24 × 12 ft

The 20 × 24 home theater

A large multi-use space with a high ceiling. Needs sensitive speakers, real amplifier power, and a bright display to fill it.

Recommended layout: 7.1.4 Atmos

Alternative: 5.1.4

The full experience: 7.1 plus four overhead speakers.

SCREEN20 ft wide24 ft longSEATLRCSLSRRLRRTFLTFRTRLTRRSUBSUB2

Main seat

14.9 ft

from the screen wall (62%)

Viewing distance

13 ft 11 in

eyes to screen

TV size

115"

124–139" is cinematic

Max projector screen

140"

lens 13 ft 3 in–20 ft 4 in back

First room mode

24 Hz

length axis

Volume

5760 cu ft

closest to Louden A

Display

A 98 to 115 inch Mini-LED TV for a bright open room, or a 130 to 140 inch ALR screen with a 3,000+ lumen laser projector.

Seating

A large sectional at about 15 feet. Surrounds will be far from the seats; aim them and raise the level a few dB.

Speaker measurements

From the left wall, from the front wall, and floor to tweeter. Angles are from the main seat.

SpeakerLeft wallFront wallHeightAngle
Front Left3.5 ft1 ft3.3 ft25°
Front Right16.5 ft1 ft3.3 ft25°
Center10 ft1 ft2.8 ft
Surround Left1 ft15.7 ft4.8 ft95°
Surround Right19 ft15.7 ft4.8 ft95°
Rear Surround Left5.3 ft23 ft4.8 ft150°
Rear Surround Right14.7 ft23 ft4.8 ft150°
Top Front Left6 ft6.1 ft12 ft25° / 42° up
Top Front Right14 ft6.1 ft12 ft25° / 42° up
Top Rear Left6 ft23 ft12 ft154° / 44° up
Top Rear Right14 ft23 ft12 ft154° / 44° up
Subwoofer5 ft1 ft0.8 ftn/a
Subwoofer 215 ft1 ft0.8 ftn/a

What to expect in this room

  • High-sensitivity (90 dB+) towers and a 9 channel receiver with pre-outs, or separate amplification.
  • Two large ported subwoofers; the room volume demands it.
  • Rugs, drapes, and absorptive furniture matter more here than in any smaller room.
  • Top Rear speakers hit the back wall before reaching 45° elevation. Mount them as far back as the room allows.
  • Two subwoofers at the front-wall quarter points (or opposing mid-walls) even out bass between seats. Run the subwoofer crawl to confirm.
  • length and height are close to a 2:1 ratio: every mode of the shorter dimension lands on a mode of the longer one.
  • 8 pair(s) of axial modes below 200 Hz coincide within 5%. Expect a strong peak at those frequencies.

Gear that fits this room

All categories

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Polk Audio Signature Elite ES20

Surrounds or a small-room stereo pair on a budget

Polk Audio Signature Elite ES20

Price tier 1 of 4
  • 2-way bookshelf, 6.5" woofer
  • 1" Terylene dome tweeter
  • 88 dB measured sensitivity
  • Bass to ~35 Hz in-room (ASR)

Audio Science Review measured genuinely deep bass and smooth, wide horizontal dispersion, and recommended it outright at its price. That wide dispersion and easy load make it a good surround or small-room front pair.

Polk Audio Reserve R700

Front left/right in medium to large rooms

Polk Audio Reserve R700

Price tier 3 of 4
  • 3-way tower, dual 8" woofers + 6.5" mid
  • 1" Pinnacle ring radiator tweeter
  • 88 dB sensitivity, 8 ohm nominal
  • 38 Hz (-3 dB), ported

A three-way tower that measured within roughly plus or minus 2 dB on-axis at Erin's Audio Corner with real bass extension to about 40 Hz, so it can play full range in a medium room. It shares drivers with Polk's flagship Legend series at a fraction of the price.

SVS SB-1000 Pro

Small rooms and music-focused systems

SVS SB-1000 Pro

Price tier 2 of 4
  • 12" driver, sealed
  • 325 W RMS / 820 W peak
  • 20 Hz to 270 Hz (+/-3 dB)
  • SVS app with 3-band PEQ

A compact 13-inch sealed cube that Audioholics found goes well beyond entry-level performance, with app control, parametric EQ, and clean 20 Hz extension. The natural pick for small rooms, music-first systems, or a pair on a budget.

Denon AVR-S670H

Basic 5.1 rooms and apartments

Denon AVR-S670H

Price tier 2 of 4
  • 5.2 channels, 75 W/ch
  • 3 of 6 HDMI inputs 8K/4K120
  • Audyssey MultEQ
  • Dual sub outs, no pre-outs

The least expensive Denon with current HDMI 2.1 gaming support and HEOS streaming. It is a sensible starting point for a straight 5.1 room, but it has no height channels and no pre-outs, so it cannot grow into Atmos.