Class 0 acoustic foam sheets can be used as part of suitable podcast and recording booth treatment where the room needs reflection control and the stated fire information is appropriate to the project. Good booth sound still starts with room choice, microphone position and background noise.
Foam can reduce reflected speech inside the space. It cannot make a noisy room silent or replace the structural isolation needed to stop outside sound passing through walls and doors.
Quick answer: how should acoustic foam be used in a podcast booth?
Treat the surfaces that return strong speech reflections into the microphone, usually nearby side walls, the area behind the speaker, and sometimes the ceiling and wall behind the microphone depending on the microphone pattern. Start with the microphone and speaker position, then add absorption in stages. Use Class 0 foam where its documented fire information matches the project.
Podcast audio problems are not all the same
A recording can sound poor because of:
- room reverberation
- flutter echo
- hard desk reflections
- background traffic
- computer fan noise
- ventilation noise
- electrical hum
- microphone too far from the speaker
- an unsuitable microphone pattern
- sound leaking through the door
- low-frequency room resonances
Acoustic foam mainly addresses the reflected-sound part of that list.
Before covering the booth, identify what you actually hear.
Get the microphone closer before buying more treatment
Microphone distance has a major effect on the ratio between direct speech and room sound.
A microphone placed unnecessarily far from the speaker captures more of the room.
Moving it closer can increase the level of direct voice relative to reflections and background noise.
That does not mean speaking directly against the grille. Follow the microphone manufacturer's recommended working distance and use a pop filter where appropriate.
Room treatment and microphone technique should work together.
Choose the quietest practical location
A booth next to a road, boiler, server rack or noisy air-conditioning unit creates problems that foam cannot solve.
Before installing treatment, listen for:
- traffic
- neighbours
- footsteps above
- plumbing
- computer fans
- heating and ventilation
- refrigerators
- electrical buzz
- outside voices
If possible, choose a quieter room or move the recording position away from the noise source.
The guide Does acoustic foam soundproof a room? explains why absorptive foam is different from sound isolation.
Treat the wall behind the speaker
For spoken-word recording, the wall behind the presenter can be an important reflection surface.
The voice travels forward towards the microphone, but it also radiates around the room. Reflections from the wall behind the speaker can return towards the microphone and add room tone.
An absorptive area behind the presenter is therefore a useful starting point in many booth layouts.
Do not restrict treatment to a narrow square directly behind the head. Think about the wider reflection zone around the speaking position.
Side-wall reflections in a narrow booth
Small booths put walls close to the microphone.
That means side reflections can return very quickly.
Treating the nearby side walls can help reduce the hard, boxy character caused by parallel surfaces.
Where two people face each other across a desk, consider both microphone positions. A layout that works for one host may leave the second microphone close to an untreated reflective wall.
Multi-host booths need a wider treatment zone.
What about the wall behind the microphone?
It depends on the microphone.
A cardioid microphone is less sensitive to sound arriving directly from its rear than from the front, but reflections can still reach the microphone from many angles.
Other polar patterns behave differently.
Rather than assuming one wall always matters most:
1. check the microphone polar pattern 2. set the speaking position 3. listen to the room 4. record a short test 5. treat the surfaces causing the strongest audible reflection
The wall behind the microphone can still benefit from treatment, particularly in very small booths, but it is part of a complete layout.
Ceiling reflections
Podcast booths often have low ceilings.
Speech can reflect between the desk, floor and ceiling and return quickly into the microphone.
A suitable ceiling absorber can help, but overhead installation requires secure fixing.
The current All Foam Class 0 sheets are supplied unbacked. Select the mounting method separately and make sure it is suitable for overhead use, the substrate and the complete fire specification.
Do not cover:
- smoke detectors
- sprinklers
- ventilation grilles
- lighting that requires clearance
- service access points
Desk reflections
A large hard desk can sit directly beneath the microphone.
If the microphone is low and close to the desk, speech can reflect from the desktop into the capsule.
Possible improvements include:
- raising or repositioning the microphone
- moving the microphone away from the desk edge
- using a smaller work surface
- adding a suitable soft desk surface where practical
- changing the speaking angle
Do not use wall foam as a substitute for fixing a poor desk and microphone geometry.
25mm or 50mm for a podcast booth?
The current AFPCLS0 range is available in 25mm and 50mm thicknesses.
25mm uses less internal booth space and can suit tight clearances.
50mm provides a deeper absorptive layer where the booth has enough room.
Small booths need careful balance. Adding very large areas of thin high-frequency absorption can make the booth sound dull while low-mid and bass problems remain.
A deeper treatment can be useful, but low-frequency control may still require dedicated broadband or bass treatment.
How much foam should a booth use?
Do not automatically cover every wall.
Start with:
- wall behind the speaker
- nearest side reflections
- ceiling reflection area where required
- other strong hard surfaces near the microphone
Then record again.
If the room still sounds lively, add treatment to the next most important surface.
The guide How much acoustic foam do I need? shows how to measure each treatment zone and convert it into sheet quantities.
Class 0 vs standard acoustic foam for a podcast space
For a domestic podcast setup with no named Class 0 requirement, the current All Foam acoustic sheet option is still the flat Class 0 grade, provided its technical data and available thicknesses suit the room. The former standard flat acoustic sheet is no longer supplied.
For a commercial booth, shared workspace, education setting or project where a specific fire classification is required, the AFPCLS0 data may be especially relevant.
Do not choose Class 0 simply because the booth contains electronics. Choose it because the fire documentation, format and acoustic role match the project.
Read Class 0 vs standard acoustic foam before specifying the grade.
Ventilation matters in a small booth
A sealed recording booth can become uncomfortable quickly.
People produce heat, computers generate heat and a small enclosed space needs fresh air.
Do not block ventilation with acoustic foam.
If ventilation noise is entering the microphone, the answer is not simply to cover the grille. The ventilation system may need quieter fans, lined ducts, bends, larger duct area or other acoustic design while maintaining safe airflow.
For a professional booth, ventilation should be considered from the beginning.
Fire information in a commercial booth
AFPCLS0 is an open-cell acoustic and thermal polyurethane foam manufactured with impregnated fire-retardant compounds.
The current data sheet states:
- Class 0 to BS 476 Parts 6 and 7
- Class 1 surface spread of flame under BS 476 Part 7
- UL94 V-0
- UL94 94-5V
Those figures relate to the product data.
A finished booth may also include:
- timber framing
- plasterboard
- fabric
- adhesives
- electrical equipment
- ventilation components
- doors and seals
The complete installation still needs to meet the requirements that apply to the project.
Avoid the "foam box" mistake
A very small booth lined on every surface with thin foam can sound unnaturally dry at high frequencies while retaining low-frequency colouration.
That is not the same as a neutral recording room.
Use a balanced treatment plan and test real speech.
Listen for:
- excessive sibilance
- boxiness
- long low-frequency decay
- flutter
- hollow desk reflections
- unnatural deadness
- changing tone when the speaker moves slightly
A useful booth should make speech clearer without forcing every recording to sound closed-in.
Two-person and interview booths
With two speakers, the geometry becomes more complicated.
Each microphone can pick up:
- its own speaker
- the other speaker
- room reflections
- desk reflections
- headphone spill
- background noise
Keep microphones close to their intended speakers and use polar patterns carefully.
Treat the larger shared reflection zone rather than building a tiny absorber around only one microphone.
Common podcast booth mistakes
- Calling acoustic treatment soundproofing.
- Putting the microphone too far from the speaker.
- Treating only the wall behind the microphone.
- Covering ventilation.
- Ignoring desk reflections.
- Using every available wall surface without testing.
- Assuming Class 0 automatically means better voice recording.
- Fitting overhead foam with an unsuitable fixing system.
- Building a visually impressive booth that is uncomfortable or too small to use.
- Forgetting that two-person booths need a wider reflection plan.
Quick answers about acoustic foam for podcast booths
Does acoustic foam make podcasts sound clearer?
It can reduce unwanted room reflections and reverberation, which can improve speech clarity when the microphone and room are set up properly.
Will acoustic foam stop outside noise?
Not by itself. Outside noise normally requires structural sound-isolation measures or a quieter recording location.
Where should foam go in a podcast booth?
Begin with the wall behind the speaker, nearby side-wall reflection zones and other hard surfaces returning speech into the microphone. Ceiling treatment may also help.
Is 50mm acoustic foam better for voice?
Greater depth can broaden useful absorption compared with a thinner sheet, but the complete result depends on material, area, placement and room. It is not a universal guarantee.
Do I need Class 0 foam for podcasting?
Not automatically. Use it where its stated fire information is required or appropriate to the project. The former All Foam standard acoustic sheet is no longer supplied; for current purchases, assess the Class 0 flat sheet against the room and project requirements.
Build a booth around clear speech
The best podcast booth is not the one with the most foam.
Choose a quiet location, position the microphone close enough for strong direct speech, treat the surfaces returning the most troublesome reflections and keep the space safe and comfortable.
For current Class 0 sizes, 25mm and 50mm thicknesses and technical information, view Class 0 Acoustic Foam Sheets.
