I recently purchased an Aisidra Bluetooth Transmitter/Receiver (Amazon non-affiliate link). This allows audio from a wired input device to be wirelessly transmitted to two Bluetooth devices, distinguishing it from similar products that can only send to one. Analogue input is supported via 3.5mm and RCA connectors, as well as digital input via optical.
My specific use case is to connect it to my iPhone via a standard 3.5mm audio cable, and then share audio of a TV program, movie, audiobook, etc. between two sets of AirPods worn by myself and my partner. Apple have a native “share audio” feature built right into iOS and AirPods, and we’ve been using it happily for a couple of years. Unfortunately, iOS 17 has introduced an unreasonable number of bugs into this flow, and using it is now an exercise in frustration. More on that in a future blog post, perhaps.
Note: the Aisidra can also function as a Bluetooth receiver, converting the output of a wireless device to a wired connection if that’s something you need. I don’t, and so have not evaluated it in this review.
In the Box
- The transmitter;
- a 3.5mm plug to 3.5mm plug Auxiliary (aux) cable;
- a 2 x RCA plug to 1 x 3.5mm plug cable;
- a Toslink plug to Toslink plug optical cable;
- a USB-C to USB-A (boo!) cable; and
- some stuff I can’t read.
The Great: It Talks!
Upon powering up the device for the first time, I discovered that it includes voice prompts, and useful ones at that. As a blind person, discovering that a product manufacturer has integrated legitimately helpful speech output into a product is a joyous thing (and clearly something I missed while reading the product description).
Specifically, the US English voice has informed me about all of the following so far:
- The current operating mode (receiver vs transmitter);
- the selected type of audio input (digital optical vs analogue);
- Bluetooth pairing when it starts, succeeds and fails, and the same for reconnection of previously-paired devices;
- power on and off events;
- the state of the voice prompt setting when toggled; and
- confirmation of the device memory being cleared (e.g. to remove existing pairings).
The voice also reminds you to make sure your analogue or optical cable is connected, based on the selected input source. At least via analogue (I haven’t tried digital yet), these reminders are fired even when something is already connected, so they’re less useful than they otherwise might be, but it’s a decent cognitive accessibility feature nonetheless.
The prompts are delivered by a fairly loud speaker, and not sent to the device(s) connected to Bluetooth. I haven’t discovered any means of adjusting their volume, although they can be toggled on and off. I haven’t tried receiver mode, so I don’t know if they would be sent to a wired output device in that case but I suspect not.
- Pairing is straight forward: put a device in pairing mode (e.g. using the button on an AirPods case), hold the appropriate button on the transmitter, and wait for either success or failure via a timeout. Reconnection to remembered devices is similarly easy.
- Relative synchronisation between two connected Bluetooth devices is low. When wearing one AirPod in each ear from two separate sets, the effect is of the audio being slightly out of phase between them, making it seem panned more to one side. In other words, it’s not perfect, but nor is there a significantly noticeable disparity. For two people wearing different headphones it’s more than adequate.
- The latency between the wired audio input and wireless endpoints is also quite reasonable. I wouldn’t want to do a lot of on-screen typing with it, but nor do I find myself e.g. overshooting my desired focus position when swiping with VoiceOver because of the delay.
- During an hour-long listening session with two sets of AirPods connected, and both people staying in range, the audio didn’t drop out once.
- It’s USB-C powered.
- A play/pause command, triggered by a squeeze on the stem of any connected AirPod, is passed through to the wired audio device.
- If the audio output from a wired device is too quiet, there is an effective volume boost feature with three levels.
- Low-latency and regular variants of the aptX codec are supported, if your Bluetooth devices support them. AirPods do not, and so SBC is the fallback. Not sure about AAC.
- The wireless range is terrible. Caveat emptor that we live in a house with concrete walls, and that the reader is probably not familiar with its layout. Nevertheless, with my AirPods connected directly to my phone, I can leave my phone in one room and stray pretty far from it (including to another floor) without dropouts or a complete disconnect. With the Aisidra positioned in a room on the lower story, I can’t walk halfway up a 13-step staircase, which starts in that same room, without the audio becoming unlistenable.
- When audio dropouts happen, e.g. because one device is becoming out of range, they affect both connected devices even if only one is far from the transmitter.
- The analogue input is low-quality and does not sound clean. Some content, e.g. Hannah Rarity’s strong female vocals in Gloomy Winter by Niteworks, induce a fuzzy static, reminiscent of bad tuning and overzealous compression on radio stations. I find it passable for TV programs and the like, and a particular Amazon review suggests that the digital input offers superior results so hopefully I’ll have a chance to try it soon.
- Additional Consumer Control commands, e.g. next or previous via two or three squeezes of an AirPod stem respectively, don’t work for me. This may be significantly annoying for some people. I didn’t try a squeeze and hold for Siri.
- Codec selection is based on the best available option supported by both Bluetooth devices. Even if one device supports a better codec than the other, they will both use the lower quality option. In practice this isn’t an issue for us when both using AirPods.
The Ugly: It Doesn’t Have a Battery!
This may be another case of me not thoroughly reading the product page. I searched it for the word “battery” just now, there is no mention and so I’d argue it’s ambiguous at best.
Regardless… it needs to be connected to a power source to work! There is no battery to charge up, and the ease of pairing and reconnection are practically negated by needing to plug it in first. I tried connecting it directly to my iPhone via USB-C; it powered on and my phone’s audio stopped coming out of the phone’s speaker. But it didn’t seem to act as a USB audio device.
I suspect that this will be a dealbreaker for us. We share audio a lot while eating, and there is no electrical outlet near our dining table (the bad design decisions in our house provide plenty of fodder for a future blog post too). It can be placed somewhere else, range permitting, but my phone also has to be proximal to it because of the audio cable. As such, adjusting volume or carrying out other actions with it across the room is not ideal, nor is the prospect of buying it its own power bank.
There’s a lot to like about this device: good things which contribute to the exact use case I bought it for, as well as excellent voice assistance, and these help to offset some of its faults. On the other hand, the prospects of solving the power delivery problem, and finding a way to get optical audio out of my iPhone for better quality, are not appealing.
The frustrating shortcomings, and unmet assumptions, make this more disappointing than if it had simply been a lower-quality product overall. I’ll endeavour to update this post with additional relevant details if I stick with it. If you decide to check it out for yourself and are blind or have low vision, the next section has information that may help.
All physical orientation information in this section assumes that you have the device resting on a flat surface, rubber feet side down, and the five connectors facing away from you.
With your hand resting on top of the device, and your fingers extended down to feel the back face, the connections from left to right are:
- 3.5mm analogue audio;
- optical audio (Toslink);
- the same 3.5mm and digital audio connectors repeated; and
I assume that one pair of 3.5mm and optical audio connectors is intended to represent input, and the other output. In my analogue testing with a standard aux cable, though, each one can be used for either, and so maybe the intent is that two wired devices can be connected as outputs in receiver mode.
The top face has a screen surrounded by four long, roughly semi-circular buttons (one on each side), the functions of which are as follows:
- Bottom/below the screen: toggle power on and off.
- Left: toggle between the four volume boost settings on each single press. The choices are “off”, or individual levels from one through three. If held down, voice prompts can be turned on and off. They are enabled by default.
- Right: trigger reconnection to previously-paired devices if pressed once, or initiate pairing to a new device if held down.
- Top/above: toggle between analogue and optical audio on a single press, or clear the device memory (including Bluetooth pairing) if held down.
The front face has a toggle switch that you can click between two positions to set the operating mode of the device: left is receiver, right is transmitter.
There is nothing of interest on the left and right faces, other than two adjustable antennas (one per side). These are similar to what you may find on e.g. some wireless access points or routers; you can pull them outwards so that they point left and right once they click into place, rotate them so that they point upwards, etc. These are probably just for show, and don’t actually help with signal dispersion in any notable way.
If you need any additional pointers, I’m happy to help if I can: Ask away on Mastodon.