Office pod acoustics, in plain language
Acoustic specifications are where pod quotes stop being comparable. Two suppliers quote two numbers, neither says which standard the number came from, and the decision gets made on the brochure instead. This page explains every term you are likely to meet, what it actually measures, and the one question to ask about each. It is written for someone holding a quote, not for an acoustician.
Start here: blocking sound and soaking it up are different jobs
Almost every misunderstanding in this subject comes from one place. There are two entirely separate things a material can do to sound, they are measured by different numbers, and a supplier quoting one while you are asking about the other is the single most common reason two quotes look the same and are not.
Sound insulation is stopping sound getting from one side of a wall to the other. It is about mass, layers, seals and the absence of gaps. It is what decides whether the person outside the pod can hear your call.
Sound absorption is soaking up sound inside a space so it does not bounce around. It is about soft, porous, fibrous surfaces. It is what decides whether the inside of the pod sounds like a comfortable room or a shower cubicle.
You want both, and they are not interchangeable. A pod lined with beautiful acoustic felt and no mass in the walls will sound lovely inside and leak your conversation into the office. Get straight which one a number refers to before you compare anything.
ISO 23351-1 and speech level reduction
This is the one that matters, and it is the only one written specifically for pods rather than borrowed from building construction.
ISO 23351-1 measures how much a pod reduces the level of speech escaping from inside it, with the pod fully assembled: doors closed, seals engaged, ventilation running, exactly as it would sit in your office. The result is a single figure in decibels, and it is the only number that describes the finished product rather than a sample of its wall.
The standard sorts results into classes. Class A is a reduction of 30 dB or more, Class B is 25 to 30, Class C is 20 to 25, Class D is 15 to 20. A FocusPod is laboratory tested at greater than 29 dB under ISO 23351-1.
What to ask: for the test report covering the exact model you are quoted, not the range. Performance varies between models, and a figure quoted for a supplier's best pod does not describe their smallest one.
The decibel, and why the numbers feel smaller than they are
Decibels are logarithmic, which is why a difference that looks small on paper is large in a room. A reduction of 10 dB is heard as roughly half as loud. So a pod at 30 dB is not a fifth better than one at 25 dB; it is a meaningfully different experience for the person sitting outside it.
It works the other way too, which is worth knowing before you over-buy. Once speech coming out of a pod drops below the general noise level of the office around it, nobody can pick it out, and further reduction buys you nothing you can hear. A typical open-plan office runs somewhere around 55 to 65 dB(A). Normal conversational speech is around 60 dB(A) at a metre.
What to ask: what the ambient noise level is where the pod will go. A quiet library-like floor needs more reduction than a busy sales floor, because there is less background noise to hide the conversation.
Speech privacy and speech intelligibility
These sound like the same thing and are opposites. Intelligibility is how much of a conversation can be understood. Privacy is achieved when intelligibility falls low enough that a listener cannot follow what is being said, even if they can tell someone is speaking.
That distinction matters because privacy does not require silence. You do not need a conversation to be inaudible, only unintelligible. Most people asking for a soundproof pod actually want speech privacy, and it is a much more achievable and much cheaper target.
What to ask: whether you need privacy or quiet. A recruiter doing confidential interviews needs privacy. Someone escaping noise to concentrate needs quiet inside, which is a different specification.
STC, Rw and why a wall rating is not a pod rating
Sound Transmission Class is the North American rating for how much sound a building element blocks. Rw, the weighted sound reduction index, is the European and international equivalent. Both are laboratory measurements of a wall, a door or a floor as an isolated element.
Neither was designed for a pod, and the difference is not academic. A pod is not a wall. It is a small enclosure with a door, a seal, a glazed front, a ventilation path in and out, and joints where panels meet. Every one of those is a route for sound, and none of them appears in a test of a wall panel on its own. A supplier quoting an impressive STC or Rw figure may be quoting their panel, not their pod, and the assembled product can perform very differently.
What to ask: whether the figure describes the assembled pod or a sample of its wall construction. If it is the wall, ask for the ISO 23351-1 figure for the pod instead.
NRC and alpha w, the absorption numbers
Noise Reduction Coefficient is a single number between 0 and 1 describing how much sound a surface absorbs rather than reflects. Zero reflects everything, one absorbs everything. Alpha w is the international equivalent. Both describe a material, which is the important part.
An NRC figure quoted as a headline specification for a pod is close to meaningless as a measure of how much sound gets out, because absorption is not insulation. It is a useful number if what you are being told is how the inside of the pod will sound, and a misleading one if it is offered in answer to how much your colleagues will hear.
What to ask: if a supplier leads with NRC, ask separately for the assembled pod's speech level reduction. If they only have the absorption number, that tells you something.
Reverberation, and why small rooms are hard
Reverberation is sound continuing to bounce after the source has stopped. It is measured as the time taken for sound to decay by 60 dB, usually written RT60. In a large hall it is obvious. In a pod it is subtle and it is the difference between a space that feels calm and one that is unpleasant to sit in.
Small hard-surfaced enclosures are surprisingly difficult. Parallel walls close together create flutter, voices sound boxy, and video calls pick it up even when the room seems fine to the person in it. That is what the absorbent interior lining is for, and it is why a pod with excellent insulation and no interior treatment is still a bad pod.
What to ask: what the interior surfaces are. If a pod is glass at the front and hard panel everywhere else, ask how the reverberation is controlled.
Flanking, and the gaps nobody mentions
Flanking transmission is sound taking a route around a barrier rather than through it. In pods it is the single biggest gap between laboratory performance and what you actually get: the seal around the door, the gap where the base meets the floor, the ventilation inlet and outlet, and any cable entry.
This is precisely why the assembled-product standard exists. A pod tested whole, with its ventilation running, has already accounted for all of those paths. A pod described by its wall construction has accounted for none of them.
What to ask: whether the quoted figure was measured with the ventilation running. Ventilation is a hole in the enclosure by definition, and a figure measured with it switched off is not the figure you will live with.
Airborne and structure-borne sound
Airborne sound travels through the air: speech, phone calls, music. Structure-borne sound travels through solid material: footsteps on the floor above, a lift shaft, machinery vibration through a slab. A pod is designed against airborne sound.
It is worth being clear about this before you buy. If your problem is the building services plant next door thumping through the floor, a pod is the wrong purchase and we would tell you so. If your problem is that everyone can hear everyone else's calls, it is exactly the right one.
What to ask: yourself, honestly, what the noise actually is. Sit in the space and listen for a minute before you specify anything.
Sound masking
Sound masking is adding a low, engineered background sound to a space, usually through ceiling speakers, so that speech from elsewhere blends into it and stops being intelligible. It is not white noise in the crude sense and it is not the same as playing music.
It works on the same principle described above: raise the background, and speech becomes unintelligible without becoming inaudible. It is a genuine alternative to pods for some problems, and a complement for others. It does nothing for someone who needs a private space to take a call; it helps a great deal with general open-plan chatter.
What to ask: whether your problem is a small number of people needing privacy, which is a pod problem, or general floor-wide distraction, which may be a masking problem.
Class A, B, C and D
These are the ISO 23351-1 classes, and they are the closest thing to a like-for-like grade in this category. Class A is 30 dB or more of speech level reduction, Class B is 25 to 30, Class C is 20 to 25, Class D is 15 to 20.
A useful way to read them: Class D takes the edge off, Class C keeps a normal conversation from carrying across a room, Class B handles most confidential conversations in a normal office, and Class A is for spaces where the conversation must not be followed even by someone standing beside the pod. Higher is not automatically better value, because the background noise of your own office decides how much you actually need.
What to ask: which class, under which standard, for which model. All three parts of that question matter.
Where FocusPod sits, plainly
Speech level reduction is laboratory tested at greater than 29 dB under ISO 23351-1, on the assembled pod with the ventilation running. We will send you the detail rather than asking you to take the number on trust, and every price is published so you can judge the value against anything else you are quoted.
What is included as standard
Every FocusPod arrives with laminated glass front and rear, layered acoustic insulation, adjustable ventilation, dimmable LED lighting with adjustable colour temperature, power and an occupancy light. Speech level reduction is laboratory tested at greater than 29 dB under ISO 23351-1, the international standard written specifically for pods. Every pod is covered by our five-year structural and electrical warranty.
There is no separate charge for the black or white exterior or for the standard interior palette. Other exterior colours use the displayed upgrade price, and a custom interior colour is priced per pod. All of it is listed separately as you build, so nothing arrives as a surprise on the quotation.
See it properly before you decide
Take a look inside. The film below walks through the Solo, the most compact model in the range, and the 3D configurator lets you turn any model around, change the finishes and try the furniture layouts. If you would rather be walked through it, we will do a live video walkthrough of the pod you are considering and answer questions as we go.
Quick answers
What does soundproof actually mean?
Strictly, nothing. No pod is soundproof, and a supplier using the word without a number behind it is selling rather than specifying. What is measurable is how much the level of speech is reduced, under ISO 23351-1, on the assembled pod. Ask for that.
Is a higher decibel figure always better?
Up to a point. Once speech leaving the pod falls below the background noise of your office, more reduction buys you nothing you can hear. What matters is the gap between the two, which is why the noise level where the pod will sit is worth knowing before you specify.
Can I compare an STC figure with an ISO 23351-1 figure?
No. They measure different things in different ways, one on a building element and one on a finished pod. Converting between them is not meaningful. Get both suppliers onto the same standard before comparing.
Does the ventilation let sound out?
Every ventilated enclosure has an air path, and every air path is a potential sound path. That is exactly why the assembled-product test matters and why we quote a figure measured with ventilation running rather than with it switched off.
Will a pod stop noise coming in as well as going out?
Yes, and by a similar amount, because insulation works in both directions. What it will not do is stop structure-borne noise travelling through the floor, which is a different problem with a different solution.
Now put a number on your own project
You have the vocabulary. Measure the space, count the people, decide whether you need privacy or quiet, and build the configuration. It takes a few minutes, no payment is needed, and the price is on the page.