Auditory BLS Setup Guide (For Therapists)

Introduction #

Auditory BLS can be a useful tool for therapists to use during both online and in-person EMDR sessions.

When in use, the auditory BLS tool will play tones, sounds or music to your client’s left and right ears in an alternating pattern.

In most circumstances, it is recommended that your client wears headphones for auditory BLS as this ensures good separation of the sound between the left and right ears.

If your client is using a Windows-PC or Mac computer with a pair of wired headphones then auditory BLS will work without any additional setup.

Auditory BLS Setup Requirments for Mobile Devices/Wireless Headphones #

If your client is using a tablet/phone or wireless headphones then there may be additional setup steps they need to take depending on the type of device they are using. If your client is using a device that does require additional setup, they may hear the auditory BLS in both ears at the same time or possibly just in one ear if they don’t take the required steps. These setup requirements for auditory BLS are caused by design decisions/limitations chosen by the manufacturers of some tablets/phones and wireless headphones. It’s probably fair to say that the needs of EMDR therapists and their clients were not top-of-mind when Apple and Google were creating the software that runs on their tablets and phones and this has resulted in some exceptions as to when and how auditory BLS can be used. We know how important and effective many therapists find auditory BLS and so we’ve gone to great efforts to ensure that the use of auditory BLS is available in most circumstances and that any setup requirements are clearly communicated and easy to follow. See below for more on this.

It’s also important to note that the auditory BLS setup requirements for some tablet/phones and wireless headphones are not unique to Bilateral Base and affect all online EMDR platforms. Some other platforms are not very clear about what devices auditory BLS will work on and some therapists have found they have been using auditory BLS on other platforms only to realise that it hasn’t been working as they thought (please ask us if you have any questions about this). We have addressed this in 2 ways. Firstly we have invested in the technology to make auditory BLS compatible with more tablets and phones than any other platform, for example, Bilateral Base is the only platform we’re aware of that enables clients to use auditory BLS during their online session when using an Apple iPad/iPhone. Secondly, we’ve created an online interactive guide that quickly and easily walks clients through checking their device setup before joining your sessions so that valuable time is not taken up with technical questions.


Technical Information on Auditory BLS with Mobile Devices/Wireless Headphones #

Some therapists are keen to understand what the ‘limitations’ in some devices actually are that affect auditory BLS.  So we’re including this next section here in response to this. This gets a little technical in places and is not essential knowledge, so feel free to skip to the next section if you feel it isn’t relevant for you.

Auditory BLS with Wireless (Bluetooth) Headphones #

Most wireless headphones use a technology called Bluetooth. This wireless technology provides 2 audio channels to carry sound between the device and the wireless headphones. When the headphones are being used just for listening, e.g. to music, each audio channel can be used to carry a different sound to the left and right ears. This is known as stereo sound. Most wireless headphones also have a built-in microphone which is used if someone wants to use the headphones, e.g. a phone call or a video conference call. In this situation, one of the audio channels for the wireless headphones is needed to carry the sound from the built-in microphone to the device. This leaves only one audio channel to carry sound to the wireless headphones. This results in the same sound being sent to both the left and right sides of the headphones. This is called mono sound. However, for auditory BLS, stereo sound is needed as otherwise the auditory tones will be heard in both ears at the same time and so won’t be bilateral. The solution to this is to use a microphone that is NOT the one built into the wireless headphones, usually the microphone built into the computer will be fine but another external microphone can also be used. If a Windoes-PC or Mac is being used then the additional step required to use auditory BLS with wireless headphones is simply to select a microphone other than the one built into the wireless headphones this will then free up both audio channels to carry stereo sound to the user’s ears.

Auditory BLS with Apple iPads/iPhones #

For most other online EMDR platforms auditory BLS is not possible on iPad/iPhone because of the way these devices handle sound during video calls made through a web browser. The sound will always be mono (same sound to both ears) which is not suitable for auditory BLS. We’ve solved this issue by creating a special app which contains its own sound management system. This app gets around the sound management limitations of iPads/iPhones and means auditory BLS can be used with a pair of WIRED headphones. With WIRELESS headphones there currently is no way around the limitations in iPads/iPhone because these devices do not allow the user to select a different microphone from the one built into the headphones so one of the audio channels is always taken by the microphone meaning only mono sound can be heard. please note that Apple Mac computers work differently so this DOES NOT apply to them.

Auditory BLS with Android Tablets/Phones #

Android devices that are less than ~5 years old will be suitable for auditory BLS when WIRED headphones are used. Older Android devices and some budget Android phones switch to mono sound during a video call. As with Apple iPads/iPhones wireless headphones CAN’T be used because Android devices do not allow the user to select a different microphone that is not the one built into their wireless headphones.


Essential Information You Should Know #

Quick Tips For Using Auditory BLS #

If you skipped the section above then these are the key takeaways

  • If your client uses wired headphones auditory BLS will work on any device (except for very old android tablets/phones)
  • If your client only has wireless headphones they will need to use a Windows-PC or Mac.


Auditory BLS – Interactive Setup Guide For Clients #

To assist your clients with auditory BLS setup ahead of their sessions, therapists can turn on the interactive auditory BLS setup guide for a client by clicking on their name in your ‘Practice Manager’ to edit their settings.

Once you have switched the guide on, when your client opens their session link they will be asked a couple of simple questions about their device and headphones they have available and guided through any required steps. They will then be able to test their setup to ensure all is well before joining the session. This setup generally takes just a few minutes.

Quick Tip – If you would like to see what your client would see when joining your sessions, then create a new client profile and call it e.g. ‘test client’ and ensure you have enabled the auditory BLS setup guide. Then open the invite link in a private web browsing window (This is a quick way to be able to open a session link and see things from a client’s perspective). As you navigate through the camera and audio setup you will see the additional instructions that assist a client.

We shared the following video with our user when the interactive guide for clients was first released and it may be helpful in giving you a more visual explanation.


Hearing Auditory BLS As A Therapist #

All of the above information relating to auditory BLS setup applies to the therapist’s devices setup also. So while auditory BLS will be heard correctly by the therapist in most cases there are exceptions related to wireless headphones, Apple iPad/iPhone and Android devices (see sections above if you haven’t read them already). The key thing to understand here is that what you as the therapist hears does not affect what your client is hearing so if for example you are using wireless headphones and hearing the auditory BLS in both ears at the same time (in mono) this has no impact on what your client is hearing. So as long as your client has been through the interactive setup guide and checked that they are hearing the auditory BLS correctly that’s all that matters! Please note that our special app for iPad/iPhone which enables auditory BLS to be used is only designed for clients. If you are a therapist using an iPad/iPhone to run online sessions then you should use the website version of the platform. You will hear auditory BLS in mono, but as mentioned just now, that won’t affect how your client hears it.


Auditory BLS and In-Person Sessions #

It’s important to note that none of the setup requirements for auditory BLS above apply to in-person sessions. This is because there is no need to have an active microphone when working in your therapist room and so auditory BLS can be played for a client through wired AND wireless headphones using any device.


Auditory BLS Without Headphones #

Headphones are recommended for auditory BLS, but there may be some situations where a client either doesn’t have headphones or doesn’t want to use them or can’t use them. In these cases:

  • Wired headphones can be purchased very inexpensively
  • Some therapists report being able to use auditory BLS via the client’s device speakers but you need to assess whether this is suitable for a  particular client based on the circumstances
  • Try adopting an alternative BLS technique


Update: Feb 2024 – Windows Audio Enhancements #


If you have any questions or feedback on this guide please contact us.