Does it work in a hall with no signal?

Yes. The guide's voice travels over a local Wi-Fi network created by the router the guide carries, without going through the internet. Only the preparation needs a connection: visitors should install the app and open it once before they arrive.

How many visitors can the TP-Link M7450 V3 take?

With this router we have measured real tours of about 20 people. TP-Link states up to 32 devices, which is the ceiling of its radio, not a group size, and the guide's iPhone takes one. For a group of 40, the M7450 is not enough: you need a router with more capacity, such as the GL.iNet Slate 7, which we have not tested with Echoris yet, or to split the group into two rounds.

Does Echoris translate the guide?

No. The guide speaks one language and the whole group hears the same voice. On a tour with several languages, you pick the language the group shares, often English, or run one round per language.

Which microphone do you recommend for a noisy hall?

The DJI Mic Mini, about €77, with noise cancelling on Strong, the level DJI pitches for noisy environments. According to DJI, you switch it on with a single press of the transmitter's power button; it starts on Basic, and you switch it to Strong in the DJI Mimo app. The microphone reduces the noise, not Echoris.

Why does the guide's iPhone ask for location?

Because iOS only lets an app read the name of the connected Wi-Fi with location permission, and Echoris needs it to check that the iPhone is on the router's network. Echoris does not store or share the location.

Do visitors have to sign up or pay?

No. They install Echoris for free, open it once with a connection before they arrive, scan the guide's QR code from the app and hear the tour on their own phone, with their own earphones.

At the time of writing, it had not yet taken place. This article covers the preparation: the challenge, the setup and why we chose it. Once the tour has happened, we will share how it went.

Companies

Guided factory tours: how we prepared the audio

Echoris editorial team

Published 15 October 2026Updated 23 October 20268 min read

Guided factory tours: how we prepared the audio

Inside the hall, the machines set the pace. The person leading the tour turns to explain what happens on that line, and the group leans in to hear. The people at the front catch half of it. The people at the back just watch lips move.

Outside, in the yard, the noise changes but does not go away. And inside or out, the same thing is true: there is no phone signal.

That is the challenge an industrial company brought to us. It shows its factory to customers and visitors. This article is a preparation case: the problem, the setup we chose and why. At the time of writing, the first real tour with this setup had not yet taken place, so there are no results to report yet.

Amazon links are affiliate links: if you buy through them, Echoris may earn a small commission at no extra cost to you. Prices are approximate, taken from Amazon Spain in mid-October 2026.

The challenge in five facts

groups of 15 to 40 people;
a route that goes in and out: production halls and outdoor areas;
halls with no signal and a lot of noise;
visitors who speak German, Italian or English;
every visitor with their own phone and their own earphones.

Each of those has a fix on its own. Together, they call for a setup planned in advance.

No signal needed, no receivers to hand out

Echoris does not use the internet during the tour. The guide's voice travels over a local Wi-Fi network the group carries with it, so it does not matter that the hall has no signal.

There are no devices to hand out, charge and collect at the end either. Each visitor hears the guide on their own phone, with their own earphones. For a company that hosts visits often, that is one less box of receivers to look after.

The only part that needs a connection is the preparation: installing the app and opening it once before arriving. It is free on the App Store and Google Play, and visitors do not need an account to hear the guide.

The network: a router that walks with the group

With 15 people or more, we do not rely on the iPhone's own hotspot: Apple says the number of connections depends on model and carrier. Our rule, in the kit for a live tour, is to bring a router once you have more than five people.

So the guide runs the iPhone in Echoris's “External Wi-Fi router” mode, with a TP-Link M7450 V3, about €110. It is a pocket router with its own battery. We use it without a SIM, because all it has to do is create the Wi-Fi network.

The guide carries it, so the network moves with the group from the hall to the yard and back. How it behaves among steel structures and machinery we do not know yet: you find out by walking the real route.

Three router settings to check before the first tour:

the network has a password: with an open network, Echoris will not let you start;
client isolation is off;
you are not on its guest network.

With either of the last two, phones cannot see each other and nobody hears the guide. And if the plant runs its own Wi-Fi, the test on the route will show whether the two networks get along.

How many people: the case of 40

It helps to keep three numbers apart, each with its own source.

About 20 people is what we have measured on real tours with this router.
32 devices is what TP-Link states for the M7450. It is the ceiling of its radio, not a proven group size. And the guide's iPhone takes one of those slots.
50 tourists per session is the app's configured limit. It is a software cap, not a tested capacity.

With 15 or 20 visitors, the setup sits within what we have already measured. With 30, it is close to the router's ceiling. With 40, it goes past it: the M7450 is not enough for a group of 40.

For those visits there are two ways forward:

A router with more capacity. For groups of more than 30, our kit article suggests the GL.iNet Slate 7, about €166. GL.iNet states more than 120 devices. We have not tested it with Echoris yet, and it has no battery: it needs a power bank of its own.
Split the group. Two rounds of about 20 people stay within what we have measured. And in an aisle between machines, a group of 40 is hard to move and hard to count.

Splitting the group is not giving up. It is the point of how to organise large groups without losing anyone: the lowest limit always wins, and in a factory the operational one carries a lot of weight.

A voice above the machines

In a production hall, you do not fix noise by turning up the earphones. You fix it at the source, with a microphone that picks up the voice and leaves the machine out. The app does not do that part: the microphone does.

We recommend the DJI Mic Mini, about €77, the clip-on mic we use. It has noise cancelling with two levels, Basic and Strong. DJI pitches Strong for noisy environments, and that is the one we suggest for the halls.

According to DJI, you switch noise cancelling on with a single press of the transmitter's power button, and it starts on Basic. You switch it to Strong in the DJI Mimo app. Before the first tour, test it with Echoris next to the loudest machine on the route.

Two practical details:

the receiver plugs into the phone's USB-C port; if the guide's iPhone has Lightning, the adapter is sold separately;
the pack comes with two transmitters, so two people can speak on the same channel: for example, the guide and the person who runs that part of the floor.

Languages: one guide, one shared language

Echoris does not translate. The guide speaks one language and the whole group hears that same voice. On a tour with German, Italian and English speakers, the practical choice is the language the group shares; often, English.

If the group has no shared language, the answer is the usual one: one round per language. With the mic's two transmitters, an interpreter can also repeat each section, at the cost of a longer tour.

The interface is a separate matter: the app's buttons and text. The version on the stores today comes in Spanish, English, Catalan and Arabic. German and Italian are done but not released yet. In the meantime, in the released version, a phone set to German or Italian may open the app in Arabic. That is why it is worth switching it by hand before the tour.

You change it inside the app, and the choice is saved:

the Profile tab, the one with a person icon;
Settings, with the gear icon;
Language, with the translate icon, and then English.

The icons look the same in every language, so the guide can point the way even if a visitor's screen is not in a language the guide reads. Better still, put it in the note visitors get before they come.

The step the guide's iPhone asks for

In router mode, Echoris checks that the guide's iPhone is on the router's network. To read the name of that Wi-Fi, iOS requires location permission. It is a system rule, not tracking: Echoris does not store or share the location.

The first time, in this order:

connect the iPhone to the router's Wi-Fi from the phone's Settings;
in Echoris, tap Use current Wi-Fi;
accept the location permission, with precise location on;
type the router's password by hand, since the app cannot read it.

The full walkthrough, with screenshots, is in how to broadcast a live tour from your phone.

The preparation checklist

Before the first tour:

walk the real route with two phones, the guide's and a visitor's;
test the audio next to the loudest machine and at the far end of the hall;
check the audio holds when you go from inside to outside and back;
save the router's network in Echoris.

In the note to visitors:

install Echoris and open it once before arriving, while they have signal, because there is none in the hall;
bring earphones and a charged phone;
if the app is not in their language, switch it to English under Profile → Settings → Language.

On the day:

router and microphone charged, plus a power bank for the iPhone;
the DJI Mic Mini on Strong, set beforehand in DJI Mimo;
a quiet spot at the start, so everyone opens Echoris and scans the guide's QR code before entering the hall;
the plant's safety rules, always ahead of the story.

What we will share next

This is the plan, not the result. Once the tour has happened, we will share what worked, what we changed and what we would do differently.

A factory tour is not about the kit. It is about the person at the back understanding why that machine matters, even while it runs right next to them.

Sources

Apple Support — Connect to the Personal Hotspot of an iPhone or iPad.
TP-Link — M7450 product page: up to 32 devices at once, checked on 16 October 2026.
Amazon — TP-Link M7450 V3 listing: up to 32 devices, checked on 15 October 2026.
TP-Link — introduction to AP isolation: with the feature on, two devices on the same wireless network cannot communicate with each other.
GL.iNet — Slate 7 (GL-BE3600): more than 120 devices at once and USB-C power, checked on 15 October 2026.
DJI — DJI Mic Mini FAQ: two noise-cancelling levels, Basic and Strong, switched on with the transmitter's power button and set in DJI Mimo, checked on 15 October 2026.
DJI — A Beginner's Guide to DJI Mic Mini: Basic is the default level when noise cancelling is switched on, checked on 16 October 2026.
DJI Store — DJI Mic Mini: the strong level is built for noisy environments, checked on 15 October 2026.

Frequently asked questions

Does it work in a hall with no signal?: Yes. The guide's voice travels over a local Wi-Fi network created by the router the guide carries, without going through the internet. Only the preparation needs a connection: visitors should install the app and open it once before they arrive.
How many visitors can the TP-Link M7450 V3 take?: With this router we have measured real tours of about 20 people. TP-Link states up to 32 devices, which is the ceiling of its radio, not a group size, and the guide's iPhone takes one. For a group of 40, the M7450 is not enough: you need a router with more capacity, such as the GL.iNet Slate 7, which we have not tested with Echoris yet, or to split the group into two rounds.
Does Echoris translate the guide?: No. The guide speaks one language and the whole group hears the same voice. On a tour with several languages, you pick the language the group shares, often English, or run one round per language.
Is the app available in German or Italian?: The version on the stores today comes in Spanish, English, Catalan and Arabic. German and Italian are done but not released yet. In the meantime, in the released version a phone set to German or Italian may open the app in Arabic, so each visitor should switch it to English before the tour under Profile, Settings, Language; the app remembers the choice.
Which microphone do you recommend for a noisy hall?: The DJI Mic Mini, about €77, with noise cancelling on Strong, the level DJI pitches for noisy environments. According to DJI, you switch it on with a single press of the transmitter's power button; it starts on Basic, and you switch it to Strong in the DJI Mimo app. The microphone reduces the noise, not Echoris.
Why does the guide's iPhone ask for location?: Because iOS only lets an app read the name of the connected Wi-Fi with location permission, and Echoris needs it to check that the iPhone is on the router's network. Echoris does not store or share the location.
Do visitors have to sign up or pay?: No. They install Echoris for free, open it once with a connection before they arrive, scan the guide's QR code from the app and hear the tour on their own phone, with their own earphones.
How did the tour go?: At the time of writing, it had not yet taken place. This article covers the preparation: the challenge, the setup and why we chose it. Once the tour has happened, we will share how it went.