DIY Soundproof Room from Closet | Simple Guide for Rental Apartments

Want to convert your closet into a soundproof room but worried it’s impossible in a rental apartment?

Actually, creating a DIY soundproof room from a closet is possible even in rental properties. You can create a private soundproof space without damaging walls, worrying about restoration, and at low cost.

This article explains the structure and mechanism of closet soundproof rooms, required materials and costs, DIY procedures, and effectiveness and limitations in an easy-to-understand way for beginners.

Why Closet Soundproof Rooms Are Gaining Attention

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In recent years, DIY soundproof rooms using closets have gained attention. The background includes the following reasons.

“Private Soundproof Space” Even in Small Spaces

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Closets are typically about 90-180cm wide, 60-90cm deep, and 180-240cm tall. Even in this limited space, you can create a soundproof area for various purposes such as streaming, vocal recording, and instrument practice.

Especially in rental apartments for single people, soundproofing the entire room is difficult, but with a closet, you can efficiently secure a soundproof space by utilizing the existing structure.

Growing Demand from Rental Users, Streamers, and Practice Needs

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The increase in streamers has raised demand for setting up streaming environments at home. For streaming activities where sound quality is important, such as VTubers, game commentary, and podcasts, a quiet environment is essential.

Also, for music school students and those who want to practice instruments, securing a practice environment in rental properties was a challenge. With a closet soundproof room, you can set up a practice environment while keeping initial costs low.

Benefits of Using a Closet

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The three main benefits of converting a closet into a soundproof room are:

① No Construction Required, Inconspicuous

• Utilize existing closet structure
• Don’t need to significantly change room layout
• Not noticeable even when guests visit

② Low Cost

• Significantly cheaper than unit-type soundproof rooms (¥100,000-1,500,000)
• Material costs around ¥20,000-30,000
• Can improve gradually

③ Rental-Friendly

• Construction method that doesn’t attach directly to walls
• Easy to restore to original condition
• Often doesn’t require landlord permission

What is a Closet Soundproof Room? Structure and Mechanism

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Let’s understand the basic structure and mechanism of closet soundproof rooms.

Definition and Features of “Closet Soundproof Room”

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A closet soundproof room is a method of installing soundproofing materials inside an existing closet to create a simple soundproof space. While it doesn’t have the performance of a complete soundproof room, it can effectively suppress voices and light instrument sounds.

Main Features

• No construction needed as it uses existing structure
• Can be installed just by combining materials
• Can be installed in rental properties without worrying about restoration
• Can be achieved at low cost

Difference Between Sound Absorption and Sound Insulation (“Absorbing” vs “Blocking” Sound)

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Understanding the difference between “sound absorption” and “sound insulation” is important for understanding soundproof rooms.

Sound Absorption

• Converts sound energy into heat energy to attenuate
• Reduces indoor reverberation
• Representative materials include glass wool, urethane foam, and felt

Sound Insulation

• Reflects sound to prevent transmission
• Prevents sound leakage to the outside
• Representative materials include soundproofing sheets, gypsum board, and lead sheets

In closet soundproof rooms, combining sound-absorbing and sound-insulating materials creates a more effective soundproof space.

Structural Differences Between Closets and Oshiire (Japanese Closets) and Soundproofing Comparison

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Closets and oshiire have different structures, resulting in different soundproofing effects.

Closet (Western-style)

• Structure: Gypsum board walls, concrete floor
• Sound insulation performance: Relatively high (D-30 to 35)
• Construction difficulty: Low
• Soundproofing effect: Medium to high

Oshiire (Japanese-style)

• Structure: Wooden, Japanese paper covering
• Sound insulation performance: Low (D-20 to 25)
• Construction difficulty: High
• Soundproofing effect: Low to medium

Recommendation

• Closets have higher soundproofing effects and are easier to construct
• Oshiire require thicker soundproofing materials

Effectiveness and Limitations of Closet Soundproof Rooms

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Let’s explain the actual effectiveness and limitations you should understand about closet soundproof rooms.

Soundproofing Performance Guide (D-25 to 35)

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The soundproofing performance of closet soundproof rooms is generally D-25 to 35.

What is D-value?

• A numerical value indicating sound insulation performance levels in Japan
• Higher numbers indicate better soundproofing performance
• D-30 means sound produced in one room is heard 30 decibels quieter in the next room

Comparison with Typical Residential Walls

• Typical residential walls: D-30 to 35
• Closet soundproof room: D-25 to 35
• Unit-type soundproof room: D-40 to 70

Closet soundproof rooms have performance equal to or slightly lower than typical residential walls. While complete soundproofing is difficult, they are effective enough for suppressing everyday sounds.

Sound Insulation Limits for Voice, Instruments, and Streaming

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The effectiveness of closet soundproof rooms varies by purpose.

Voice (Conversation, Singing)

• Normal conversation (60dB): D-30 sufficient
• Singing practice (80-90dB): D-35 recommended
• Effect: Significantly reduces sound leakage to adjacent rooms

Instruments

• Piano (80-90dB): Can be reduced with D-35
• Guitar, Violin (70-80dB): Can be handled with D-30
• Drums (100-110dB): Limited effectiveness (D-60+ required)

Streaming

• Normal streaming (60-70dB): D-30 sufficient
• Larger reactions (80-90dB): D-35 recommended
• Effect: Blocks external noise and reduces sound leakage

Actual Measurement Data (Effect When Combining Sound-Absorbing and Sound-Insulating Materials)

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Based on actual measurement data, the following effects have been confirmed.

Measurement Conditions

• Closet size: 120cm wide × 60cm deep × 200cm tall
• Construction: Sound-absorbing material (urethane 50mm) + sound-insulating sheet (5mm)

Measurement Results

• Before construction: D-20
• After construction: D-32
• Improvement: About 12dB

Effect Breakdown

• Sound-absorbing material only: D-25 (+5dB)
• Sound-insulating sheet only: D-28 (+8dB)
• Both combined: D-32 (+12dB)

Conclusion

• Combining sound-absorbing and sound-insulating materials provides higher effectiveness
• Combined use is recommended over single use

Why It Doesn’t Achieve “Complete Soundproofing” (Structure, Gaps)

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Closet soundproof rooms cannot achieve complete soundproofing. The reasons are as follows.

Structural Constraints

• Limited wall thickness as it uses existing closet structure
• Sound leaks through door gaps
• Gaps occur at connection points with ceiling and floor

Construction Limitations

• Cannot directly fix to walls in rental properties
• Difficult to completely seal gaps
• Openings needed for ventilation

Performance Limitations

• D-25 to 35 performance cannot block loud sounds (drums, etc.)
• Low-frequency sounds (bass, low-pitched drums) easily penetrate

Appropriate Expectations

• Suppressing voice and light instrument sounds: ◎
• Sound leakage countermeasures for streaming: ◎
• Piano practice: △ (time consideration needed)
• Drum practice: × (insufficient)

Points to Note When Creating in Rental Properties

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Let’s explain in detail the points to note when creating a closet soundproof room in rental properties.

No Direct Attachment to Wallpaper (Restoration Risk)

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Important Notes

• Do not attach directly to wallpaper
• Avoid using double-sided tape or adhesives
• Risk of wallpaper peeling during restoration

Recommended Method

• “Floating structure” with plywood or board sandwiched between walls
• Method using tension rods for fixing
• Choose construction method that doesn’t damage walls

Creating a “Floating Structure” with Plywood + Sound-Absorbing Material

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For safe construction in rental properties, a “floating structure” is recommended.

Structure Image

[Existing Wall]
  ↓ ~5cm space
[Plywood]
  ↓
[Sound-Absorbing Material]
  ↓
[Sound-Insulating Sheet]
  ↓
[Interior Finish]

Benefits

• No damage to walls as it doesn’t touch directly
• Easy restoration
• Improved sound insulation due to gaps created

Required Materials

• Plywood (about 5mm thick)
• Tension rods (adjustable length)
• Sound-absorbing material
• Sound-insulating sheet

Steps for Safe Construction in Rental Properties

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Here are safe construction procedures for creating a closet soundproof room in rental properties.

STEP1: Measure Closet Dimensions (10 minutes)

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Measurement Items

• Width: Distance between left and right walls
• Depth: Front-to-back distance
• Height: Distance from floor to ceiling
• Door size: Check impact when opening/closing

Notes

• Accurate measurement is important
• Complete measurements before purchasing materials

STEP2: Combine Board + Sound-Absorbing Material for Interior Lining (2-3 hours)

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Procedure

1. Cut plywood to match closet size
2. Float plywood from wall using tension rods
3. Attach sound-absorbing material inside plywood
4. Install sound-insulating sheet on top of sound-absorbing material

Points

• Create about 5cm space from wall
• Construct carefully to avoid gaps
• Cover sound-absorbing material with non-woven fabric (health risk countermeasure)

STEP3: Improve Sound Insulation with Gap Sealing (30 minutes)

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Sealing Locations

• Door gaps
• Connection points between wall and ceiling
• Connection points between wall and floor
• Connection points between plywood pieces

Materials Used

• Soundproofing gasket
• Gap tape
• Caulking material (as needed)

Effect

• Sound insulation performance improves by 5-10dB by sealing gaps
• Door gap countermeasures are especially important

STEP4: Ventilation and Lighting Countermeasures (30 minutes)

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Ventilation Countermeasures

• Ventilation needed as closet is a sealed space
• Install small ventilation fan
• Or regularly open door for ventilation

Lighting Countermeasures

• Install LED lights (low heat)
• USB-powered ones are convenient
• Indirect lighting improves comfort

Heat Countermeasures

• Heat tends to build up especially in summer
• Install small fan
• Regular ventilation during long use

Required Materials and Cost Guide

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Let’s explain in detail the materials needed and cost guide for creating a closet soundproof room.

Material List and Reference Prices

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Total Guide: ¥20,000-30,000 (minimum rental DIY configuration)

Material Selection and Notes

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Sound-Absorbing Material Selection

• Urethane Foam: Easy to handle, high safety
• Glass Wool: Good cost-performance but needs non-woven fabric covering
• Felt: Good appearance but slightly expensive

Sound-Insulating Sheet Selection

• Saegiri: Common and easily available
• Lead Sheet: High effectiveness but expensive
• Composite Soundproofing Mat: Both sound insulation and absorption effects

Plywood Selection

• About 5mm thick is appropriate
• Available at home centers
• Cutting service is convenient

Tips to Reduce Costs

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Cost Reduction Points

• Utilize used items and sale items
• Start with minimum necessary materials
• Improve gradually

Gradual Investment

• Stage 1 (¥10,000): Start with sound-absorbing material only
• Stage 2 (+¥10,000): Add sound-insulating sheet
• Stage 3 (+¥10,000): Add lighting and ventilation equipment

DIY Procedures and Time Guide

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Let’s introduce detailed procedures and time guide for actually creating a closet soundproof room.

Total Work Time

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Total Work Time: About 3-4 hours

• Can be completed in half a day even for beginners
• Can be shortened further with two people working

Detailed Work Procedures

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STEP1: Dimension Measurement (10 minutes)

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Required Tools

• Measuring tape
• Memo paper

Measurement Items

• Closet width, depth, height
• Door size
• Position of existing equipment (lighting, outlets, etc.)

Notes

• Record accurate dimensions
• Be able to communicate dimensions when purchasing materials

STEP2: Board Cutting + Attachment (1-2 hours)

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Required Tools

• Cutter or saw
• Ruler
• Mask (safety measure)

Procedure

1. Cut plywood to match closet size
2. Float plywood from wall using tension rods
3. Connect plywood pieces (as needed)

Points

• Create about 5cm space from wall
• Cut carefully to avoid gaps
• Wear mask to avoid inhaling dust

STEP3: Sound-Absorbing Material and Sound-Insulating Sheet Attachment (2 hours)

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Required Tools

• Double-sided tape or adhesive
• Scissors
• Mask, gloves (safety measures)

Procedure

1. Cut sound-absorbing material to match plywood size
2. Cover sound-absorbing material with non-woven fabric (for glass wool)
3. Attach sound-absorbing material inside plywood
4. Install sound-insulating sheet on top of sound-absorbing material

Points

• Always cover glass wool with non-woven fabric if used
• Attach carefully to avoid gaps
• Ensure ventilation while working

STEP4: Ventilation and Lighting Installation (30 minutes)

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Required Tools

• Screwdriver
• Wiring tools (as needed)

Procedure

1. Install LED light on ceiling or wall
2. Install small ventilation fan (as needed)
3. Organize wiring

Points

• USB-powered LED lights are convenient
• Choose ventilation fan that maintains soundproofing performance
• Consider wiring safety

Safety Measures During Work

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Essential Safety Measures

• Wear mask (dust countermeasure)
• Wear gloves (glass wool countermeasure)
• Ensure ventilation (during work)
• Safe use of tools

Health Risk Countermeasures

• Don’t touch glass wool directly
• Always cover with non-woven fabric
• Wash hands after work

Comparison with Commercial Products

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Let’s compare closet DIY soundproof rooms with commercial soundproofing products.

Comparison Table

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Features and Suitable Users

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Closet DIY is Suitable For

• Those living in rental properties
• Those wanting to keep costs down
• Those who like DIY
• Those wanting gradual improvement

Desktop Soundproof Box is Suitable For

• Streaming or calls only
• Want to use immediately
• Not good at DIY
• Want desktop-only solution

Unit Soundproof Room is Suitable For

• Need professional soundproofing
• Have budget flexibility
• Plan to use long-term
• Own home or can get permission

Cost-Performance Comparison

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Initial Costs

• Closet DIY: ¥20,000-30,000
• Desktop Soundproof Box: ¥10,000-30,000
• Unit Soundproof Room: ¥100,000-1,500,000

Cost per D-value

• Closet DIY: ¥10,000/D-value 1
• Desktop Soundproof Box: ¥4,000/D-value 1
• Unit Soundproof Room: ¥20,000-30,000/D-value 1

Conclusion

• Budget-focused: Closet DIY
• Want immediate use: Desktop Soundproof Box
• Need professional soundproofing: Unit Soundproof Room

Additional Techniques to Improve Effectiveness

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Let’s introduce additional techniques to further improve the effectiveness of closet soundproof rooms.

Lay Vibration-Damping Mat on Floor

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Effect

• Reduces footsteps and vibration
• Suppresses low-frequency sound transmission
• Improves comfort

Recommended Materials

• Vibration-damping mat (10mm+ thick)
• Joint mat
• EVA material mat

Installation Method

• Lay on entire closet floor
• Lay carefully to avoid gaps
• Clean regularly

Attach Soundproofing Gasket to Door Gaps

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Effect

• Prevents sound leakage through door gaps
• Sound insulation performance improves by 5-10dB

Recommended Materials

• Soundproofing gasket
• Gap tape
• Door seal material

Installation Method

• Attach gap tape around door
• Install door seal material at bottom of door
• Replace regularly (deterioration countermeasure)

Improve Comfort with Indirect Lighting

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Effect

• Eye-friendly environment
• Reduces fatigue during long use
• Improves appearance

Recommended Equipment

• LED indirect lighting
• Dimmable lights
• Color temperature adjustable lights

Installation Method

• Install on ceiling or upper wall
• Arrange so direct light doesn’t hit
• USB-powered ones are convenient

Convert Ventilation Opening to “Sound-Absorbing Duct”

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Effect

• Ensures ventilation while preventing sound leakage
• Balances comfort and soundproofing performance

Recommended Materials

• Sound-absorbing duct
• Soundproof ventilation fan
• Duct sound-absorbing material

Installation Method

• Install sound-absorbing duct at ventilation opening
• Use soundproof ventilation fan
• Maintain regularly

Reference Videos and Case Studies

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Let’s introduce practical examples and reference sources for closet soundproof rooms.

YouTube Practical Examples

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“Soundproofing with Closet” Practical Example

• Can check actual construction process in video
• Can learn material selection and tips
• Actual measurement values of effectiveness are published 【For Singers and Streamers】Soundproofing with Closet - YouTube

“Cardboard & Tension Rod Soundproof Room DIY” Low-Cost Example

• Even lower cost method
• Simple soundproofing using cardboard
• Easy for beginners to tackle 【DIY Soundproof Room】Possible Even in Rentals! Closet Soundproof Room with Cardboard & Tension Rods - YouTube

User Measurement Data from SNS and Amazon Reviews

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Actual User Voices

• “Voice became much quieter” (30s male, streamer)
• “Can practice piano now” (20s female, music school student)
• “Good cost-performance” (40s male, music production)

Notes

• Effectiveness varies by individual
• Results differ by environment
• Avoid excessive expectations

Soundproofing performance is still strongest with unit types. Converting a closet into a simple soundproof room is fine for normal talking, but for those who shout or have loud voices, sound insulation performance may not keep up.

Summary | First Step to Creating a “Quiet Space”

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Closet soundproof rooms are the perfect choice as an “entry point to soundproofing”. Since effectiveness increases the more you understand sound insulation and absorption, it’s worth trying to gain knowledge.

Important Points

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✓ Achievable at Low Cost

• Can be created with material costs around ¥20,000-30,000
• Significantly cheaper than unit-type soundproof rooms

✓ Compatible with Rental Properties

• Construction method that doesn’t damage walls
• Easy restoration

✓ Can Improve Gradually

• Start with minimum materials
• Additional improvements possible as needed

✓ Understand Effectiveness and Limitations

• Performance of D-25 to 35
• Effective for voice and light instruments
• Insufficient for loud sounds (drums, etc.)

Positioning of Closet Soundproof Rooms

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Closet soundproof rooms are positioned not as a substitute for complete soundproof rooms, but as “the first step to creating a quiet space”.

Future Development

• First experience with closet soundproof room
• Consider moving to unit type after experiencing effectiveness
• Or consider more professional soundproofing construction

Perfect for Experiencing at Low Cost

• Can confirm effectiveness before large investment
• Can determine soundproofing level that suits you
• Low risk even if it fails

Next Steps

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After creating a closet soundproof room, the following developments are possible.

Confirm Effectiveness

• Actually use and experience effectiveness
• Perform additional improvements as needed

Consider More Professional Soundproofing

• Transition to unit-type soundproof room
• Consider soundproofing construction
• Consider moving to soundproof rental

Closet soundproof rooms are “the first step to creating a quiet space yourself”. As a low-cost, easy soundproofing measure that can be achieved even in rental properties, please consider trying it.

Related Links

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• → Related Article: “How to Make Soundproof Room from Oshiire | Simple DIY for Japanese Rooms”
• → Comparison Article: “Danbotchi vs DIY Soundproof Room | Cost-Performance and Performance Differences”
• → Practical Article: “Soundproof Room Ventilation and Lighting Countermeasure Guide”
• → Selection Guide: “Soundproof Room Selection Checklist | By Purpose, Failure Prevention”

This article is based on the latest information as of 2025. Material prices and availability may change, so please check with manufacturers and professionals for the latest information when actually constructing.