I'm gonna describe a couple things I've learned along the way but haven't seen discussed here. Please correct any mistakes; I'm still learning.
Setup: iPhone bt+wifi --> CCPA adapter/Hudiy tunes bt --> truck amp+sub. RPi5 wifi off, RPi onboard bt <--> iPhone, RPi bt dongle <--> truck.
Blueteeth
Using bluetoothctl set system-alias names for both bt controllers; thank me later. Select RPi_Native controller as default and scan on. Open iPhone settings to bt to wake it up and trigger its mac address to show on the scan. Scan off. Do the Apple dance and pair mac, connect mac, trust mac.
Select dongle TPLink controller as default. Scan on. Note truck mac address on the scan. Scan off. Pair mac, connect mac, trust mac.
iPhone <--> RPi_Native << RPi5 >> TPLink dongle <--> truck
NB: If the dongle controller is powered off (bluetoothctl:show) unblock mac, power on.
Pipewire
Dropouts troubleshooting: Test/set audio buffer variables:
sudo mkdir /etc/pipewire
sudo cp /usr/share/pipewire/pipewire.conf /etc/pipewire/
sudo nano /etc/pipewire/pipewire.conf
default.clock.rate = 48000
default.clock.quantum = 1024
default.clock.min-quantum = 700 <- seeing reference to this as 'frames' (?)
default.clock.max-quantum = 2048
default.clock.quantum-limit = 8192
default.clock.quantum-floor = 64
The CCPA has 2 audio options (via its onboard 192.168.43.1): CD (outputs at 44100) or DVD (48000). Use DVD to match default.clock.rate. Can be checked using pw-top. NB: Use caution changing the CCPA wifi & bt names/settings: brickable.
Hudiy
With pw-top I found the echo_cancel module was all errors so I commented it out in hudiy_startup.sh . My use case is music and would disable phone calls if possible (haven't got that far, but will try iPhones Driving Focus mode).
RPi5
Dropouts troubleshooting with dmesg showed the CCPA was reconnecting 3-4x per song for ~ 2.3 seconds causing a momentary skip.
Fix: turn off USB autosuspend (default 2 seconds).
sudo nano /boot/firmware/cmdline.txt
append usbcore.autosuspend=-1
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@hudiy
> My intent is to have music stream via bt from iPhone to truck (with or without going through the RPi5) and use Hudiy for control.
> Without CCPA/Hudiy the bt flow iPhone-RPi_Native-TPLink-truck works deluxe.
> Also, I can bt direct from phone to truck and Hudiy will allow start/stop but little else.
The CCPA adapter appears to use wifi to transfer from phone to USB. But I'm not sure; next up is to watch USB traffic.
Any thoughts about how to proceed? I'm about tapped out. qpwgraph shows one connection: hudiy.equalizer to truck.
Your comments in this thread is where I'm going:
viewtopic.php?t=19
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You would need two separate Bluetooth adapters (e.g. the built-in module on the Raspberry Pi plus an external USB dongle).
In that case, PipeWire would also need to be correctly configured with HFP Sink/Source and A2DP Sink/Source roles - but unfortunately, we haven’t tested PipeWire in this type of setup, so we can’t confirm if it works reliably.
\Quote
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March 30: Chasing dropouts.
The CCPA definitely uses wifi to communicate via USB; what was confusing me was the phone did not show as connected to the 'AutoKit-5041' SSID, so I forced the issue: on the iPhone I switched the AutoKit-5041 IP configuration from Automatic to Manual with IP 192.168.43.100, Subnet Mask 255.255.0.0 Router 192.168.43.2, automatic DNS and joined the network: after several songs still no dropouts and the phone remains locked to the SSID; wait and see.
pw-top shows bluez_input as the iPhone and bluez_output as the truck.