Non-bluetooth USB dongle radio audio interface - Page 1
Forum section: electronics / general

author: Axk
author_rank: Regular Contributor
timestamp: October 18, 2024, 09:45:25 am
content: Hi Everyone!There are these USB stick radio headphones which don't use Bluetooth like e.g. Hyperx cloud stinger core wireless.I'm looking for a similar thing but just a (small) box with a 3.5 mm jack for earbuds with a mic.A dev board will do too.There are such things with Bluetooth, but Bluetooth has too much compression for the microphone audio as far as I know.There are also similar analogue jack -> wireless -> box -> jack interfaces I suppose for performers, but I need USB -> wireless -> box -> jack.I've found the name of the chips used in Hyperx cloud stinger core wireless - avnera av 6201/6203 but cannot find any dev boards with these chips or a full datasheet (they do sell the chips on Aliexpress).

author: Postal2
author_rank: Frequent Contributor
timestamp: October 18, 2024, 04:26:48 pm
content: I still recommend bluetooth. When it's normal, it works well. I use this one (I bought 16 bit for compatibility). And I'm very happy.https://aliexpress.com/item/1005004432112985.html

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 19, 2024, 04:26:00 am
content: Could DIY one with an ESP32, effectively replicating what Nvidia did to implement wireless HD audio for the Shield TV. Don't need any compression since Wifi has a lot of bandwidth available, also plenty of excess bandwidth to implement FEC. That in turn, can have a "game mode" that prioritizes low latency but less robustness and a "music mode" that maximizes robustness at the cost of latency.

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 19, 2024, 05:01:22 am
content: If you don't want to use BT and you want something less exotic, with documentation, you can consider the TI CC8520 & CC8521:https://www.ti.com/product/CC8521They have a reference design, but not sure there is any ready-made board available.

author: Axk
author_rank: Regular Contributor
timestamp: November 04, 2024, 10:58:01 pm
content: Thanks everyone!The CC85xx chip looked promising but looks like people with no RF experience consistently end up with boards with a range of a meter or lessThat's sad, otherwise no coding and a good reference design looked like it's not that difficult to do.But the RF part, unless you replicate the reference design PCB exactly, looks like it's always trial and error and requires multiple iterations and debugging.

author: Buriedcode
author_rank: Super Contributor
timestamp: November 09, 2024, 09:32:06 pm
content: I see two things making it difficult to find a solution to your problem:1) The addition of a mic - bluetooth has several profiles, one is purely for msuic, high qualityrelativelylow latency streaming. The other is the heatset profile, which include povision of a mic, but this is meant for phone call quality. Other systems are similar - either one-way high quality stereo with higher latency, or two way, lower quality with lower latency (real-time comms).2) If this is being used to view videos, you will need low latency to prevent lip sync issues. Standard bluetooth has a latency of >60-80ms and is clearly delayed when viewing videos. More modern bluetooth (4.2 +) can use AptX low Latency which reduces this to about 20-30ms, which is just fine. However, that codec is only used for one-way streaming, unless they've update bluetooth 5.0, I don't think this is used in the headset profile.The above is why Logitech went with their proprietary system (don't they use the Avnera chipset too?), providing higher quality audio, low latency, and two way (a microphone).I will second SiliconWizards suggestion, although you are correct in that getting something relaiable over a few metres is going to be difficult without equipment to tune antennas, or bolting on an RF front end (that are often power hungry, and can actually reduce range if they aren't cared for).Note: Aliexpress has plenty of wireless digital audio boards. With some basedoff the TI chipset, some with the old Nordic NRF24Z1 (has terrible range), and some with what appears to be low bandwidth 2.4GHz chipsets and an AVR - those tend to claim "CD quality" but in reality, only transmit audio in 10-bit.

author: Axk
author_rank: Regular Contributor
timestamp: November 11, 2024, 03:42:53 pm
content: I might give CC85xx a try, I don't need the absolute best range, just something reasonable to get through a couple of brick walls 10 meters max. It appears that the primary issues people where having with the TI reference design is the CC2590 extender chip, presumably it's difficult to power properly because it's sensitive to power supply inductance. With CC2592 it looks like it should be easier. I could try without an extender chip but I'm not sure about the range then, but with proper antenna coupling I guess it could be enough.I would copy the layout of the RF portion from the reference design but I'm planning to order cheap PCBs from JLCPCB, so the stackup will be different.I'll see if I can design the PCB to allow for some tuning and if my Nano VNA can help with that.

author: Buriedcode
author_rank: Super Contributor
timestamp: November 11, 2024, 07:24:09 pm
content: Yeah the nice thing about the TI chipsets is they provide a compatible front-end/range extender rather than having to do it discretely with seperate PA and LNA (plus antenna switches.. etc..). Given the high bandwidth and low tolerance for errors I doubt this will give super long range, but should be at least 10m.As for matching networks, I guess it doesn't have to bespot on- only if you're trying to squeeze as much range as possible, or if you're trying to save power by using the minimum possible transmit power.Ultimately, with the same PCB spaces, trace widths, and matching part values as the dev board, I don't see why it would't be that different.

author: coppice
author_rank: Super Contributor
timestamp: November 11, 2024, 07:37:31 pm
content: I would use bluetooth unless you want one of the following:High quality 2 way audio for a headset. Bluetooth still lacks a mode which does that. With so many ways now available to have a high quality wideband conversation, using codecs like opus, its frustrating that you still can't get high quality in both directions to anything bluetooth.Latency that is sufficiently predictable to avoid the synchronisation problems that keep cropping up with Bluetooth audio supporting a video source.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 12, 2024, 01:13:23 am
content: Quote from: coppice on November 11, 2024, 07:37:31 pmThe Bluetooth standards organization is really disappointing. They think of only current use cases so that by the time the standard is out to market, it's already out of date. They should replicate what the PCIe standards organization does and think so far ahead that it seems ridiculous.