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HTPC / Airplay issues with multiple speakers: My Experiments

11K views 16 replies 4 participants last post by  redzone 
#1 ·
Hello All,

I am trying to set up whole home audio on the cheap via itunes and airplay.

I live in a small 1 1/2 story with a finished basement. (1000sq above ground total)

I bought a Pioneer 1021 receiver which has airplay built in. This is on the main floor with A+B speakers in living room/ dining room respectively. This covers audio for the main floor of the house. There is also an HTPC hooked up to the receiver.

The upstairs has my main pc / server for all my audio/video files.

For the Downstairs and/or garage and/or patio - I planed to use either my laptop or android phone via AirBubble(or similar software) as a portable receiver/speaker.

My problem is when I airplay to my receiver and pc upstairs at the same time the audio is out of sync!(pc is 1/2 sec ahead of receiver creating nasty echo effect) This renders using airplay to multiple sources completely useless.

it seems to be either the PC's or airplay speakers that have issues. With Airbubble on android and the receiver playing at the same time there is no noticeable delay.

With pc speakers playing and the laptop playing (via airbubble) there's no notieable delay.

So annoying!

If anyone has any ideas please let me know. Ive read about something called airfoil so i might try that tonight but from the description im not sure it will help.

I will continue to update this thread with my ongoing experiments and hopefully the info will help others
 
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#2 ·
Not sure if Airfoil will help. I encountered this in testing several years ago.

I believe there is a buffer of 50 to 500ms between iTunes and Airplay devices to deal with lost packets and latency issues.

Not sure what you can do except not use your main pc as speakers

With Airbubble on android and the receiver playing at the same time there is no noticeable delay.
That makes sense because Apple tries to ensure that all the clients will be in sync.
 
#3 ·
so maybe if i use airbubble on the PC upstairs and use the HTPC in the living room as the iTunes source i can get the delay to be the same to all "recievers"

i tried using airbubble on the same pc as the itunes server but there was no delay (ie if i selected airbubble vs pc speakers the output was the same, no delay)
 
#4 ·
Shairport4w - Free Airplay Speaker software!

So I installed a program called Shairport4w on my laptop and upstairs pc. It does the same thing as Airfoil Speaker and AirBubble but its opensource and free.

I found if I played music only to the reciever first via air play then added the pc speakers(via shairport) and laptop(via shairport) i could get them all in sync.

Not sure if its just coincidence but for now im happy as i can seem to get them all in sync. If i have further issues with it i will post then!

BUT for now i have 2 portable speakers (android phone and laptop) and 2 floors of the house with sync'd home audio.

Next test is to run a second itunes on my htpc a the same time so i can have 2 sources so i can play 2 different hings to 2 different rooms.
 
#5 ·
upon further inspection its still off a bit and can be noticeable at locations where the 2 different speakers overlap..
btw not sure if i mentioned all devices are hard wired but the laptop and android phone.

So Summary

Android(airbubble) + receiver + laptop(shairport) = sync
PC + Android or receiver = not in sync
PC(Shairport) + android/Reciever = not in sync but close!

So obviously its the PC upstairs.

I plan to try and run itunes from the HTPC downstairs so that itsplaying music to all devices but it self. hopefully that will sync everything up.
 
#6 ·
Good luck. Honestly, I don't think you'll ever get it perfect unless all your clients are airplay receivers.

I have encountered similar issues with Sonos and with some earlier audio streamers about 4 or 5 years ago.
 
#7 ·
This is not helpful to you but maybe to another person viewing this thread later. I had more speakers than outputs and I did not want to double up on the speaker wire. I have some in the bathroom, bedrooms, basement, living room and outside. I use airplay but I have two receivers. The receiver with the ATV has its optical output running to the optical input on the second receiver. There is no delay that I can notice.
 
#9 ·
Some success some failure.

so more messing around.

[fail] I cannot get the receiver and android airbubble app in sync with the pc upstairs no matter how hard i try. Even if i can get it close at the start it slowly gets worse and worse.

[win] I did find if i used the htpc(via shairport) and outputted it to my receiver at the same time as the upstairs / laptop i can get it pretty much bang on.(cant tell if there's a delay)

must be that the Shairport software reports the pc's as airport expresses and not an airplay device.

so this method works fairly well but takes some extra steps in that i need to turn on htpc, select the htpc output on the receiver. Where as airplay the reciever can be off and it will just turn on the receiver with no interaction.

BUT for some reason i have to have the tv on in order for the receiver to keep playing the music. this must be an HDMI protocol thing so im going to play with some settings on the receiver.

i also have to figure out how to make itunes prevent the pc going to sleep.
 
#10 ·
The reason why you are getting mixed results with AirPlay sync is because you are using 3rd-party software that does not implement the audio synchronization portion of the AirPlay (formerly branded as AirTunes) protocol correctly or even at all.

All 3rd-party non-Apple licensed AirPlay speaker/receiver implementations (i.e. AirBubble, ShairPort, Airfoil, etc.) are created based from reverse-engineering efforts of the RAOP protocol, and some don't implement the synchronization portion at all. In fact, AirBubble's product description page here even says that it won't stay in sync with other AirPlay devices. The fact that it works for you is probably luck. I'm willing to bet that if you go just out of reach of your Wi-Fi network with your Android device and cause audio to stutter and then come back into range, it will be out of sync with iTunes and won't correct itself unless you restart the song.

Ultimately, the better the reverse engineering and understanding of the protocol, the better the 3rd-party speaker/receiver will stay in sync with iTunes and other official licensed AirPlay devices (such as your Pioneer receiver).

A comprehensive list of official Apple licensed AirPlay devices (all hardware) can be found here. These should most definitely stay in sync with iTunes.

As far as 3rd-Party implementations are concerned, Rogue Amoeba's Airfoil Speakers is definitely among the best. I've seen very few complaints from people online saying they get out of sync with iTunes or other AirPlay devices when using Airfoil.
 
#11 ·
that still doesn't explain why my airplay certified receiver( pioneer 1021) wont stay in sync with my pc upstairs that's playing the music.

I tried multiple times and had no luck at all. but with softsqueeze and logitec media server (ie squeezebox) it all works great.
 
#12 ·
To make sure I'm understanding you correctly, your PC upstairs is running iTunes which is playing both through the PC speakers and to the AirPlay (Pioneer 1021) receiver?

If so, that is certainly strange. Is it never in sync or just sometimes out of sync?

AirPlay 'sync' packets are sent via UDP, and unlike TCP the delivery of UDP packets to there destination is not guaranteed. There is a good possibility that somehow your receiver is not receiving those packets sent by your PC and as a result the Pioneer receiver is not receiving the necessary information to stay in sync with the PC.

Possible reasons include (but certainly not limited to):
1. The PC's firewall is blocking the ports used to send the UDP 'sync' packets
2. The network router/switch is dropping or blocking those UDP packets
3. Poor network connectivity of your PC or receiver (if wirelessly connected)
 
#13 ·
i tried for a good week straight. my network is all wired. i tried disabling all firewalls. i did all sorts of stuff.

My best guess is that the pioneer while labeled airplay compliant just doesn't sync properly.

if i had a second airplay device i could see if that was the case but frankly the logitec media server works fine and is free.
 
#14 ·
Its my understanding that all Apple licensed AirPlay devices use the same chipset manufactured by a company called BridgeCo. So chances are that is not the problem.

For reference to others, what network hardware (make/model is being used in the configuration)? And what PC make/model, are you using to stream iTunes?

Then perhaps others looking at this thread in the future can see if there is a common issue.
 
#17 ·
I think it prob is the receiver and makes me not trust the system as a whole since you wont know what devices will buffer right untill after youve bought them.

It also still didn't solve my want to use multiple pc's as zones around the house so Logitech media center (squeezebox) is what i went with. Its still not prefect in the sence that the softsqueeze program sometimes stops responding but it does not happen often.
 
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