Unable to solve...please help! (barix / stl question)

[duckfan98]

I need an expert here!

I cannot get PCM audio to transport over my STL via Barix link. I get horrible drops, jittering, etc....however, my IP link is solid at 50-70 MBPS. Not the public internet, a direct noise free 5ghz link. Very fast. MPEG compression works good, but I do not want to run MP3 for obvious (quality issues). Here is my complete chain...please take a look over and let me know if I am missing something obvious:

Source material WAV files, 32khz MPEG Level 2 5:1 compression ---> Automation System --> AES out to console via Digigram VX222v2 Card ---> EAS --> Henry Balanced to Unbalance box ---> Barix Instreamer 100 ---> IP LINK --> Barix Exstreamer --> Shielded RCA cable w/ ferrite rings --> Henry Unbalance to balanced Box ---> M-Audio 192 card (48khz setting) --> Breakaway Broadcast ---> M-Audio 192 Card out ---> Fxi60 Exciter (L/R) ---> FM1C1 transmitter

MPEG on the barix boxes work fine. Whenever I switch to PCM (any format) I get the horrible audio.

Am I missing something obvious!??!?

 

[Bojcha]

What units You use for link?

 

[duckfan98]

Ubiquity 5ghz, 25dbi units.

The connection is rock solid...

 

[Bojcha]

try to:
- turn off "compression"
- turn ON "Fast Frame"
- Turn Off "Bursting"
- Turn On or Off "Noise Imunity" (see what helps)
- try Rate: Conservative
- Turn OFF Auto ACK and set it manually. If there is no distance in units, find some ACK calculator on NET.

 

[chriscollins]

Slightly off topic, but why is your source material compressed?

On topic, Turn on Fast Frame and change rate to Conservative.

Oops, I see someone beat me to my tips while I was typing...

 

[duckfan98]

Hi Chris,

This is the music library from radio-mall.com.....

I didnt know it was compressed until after we bought it.....

 

[RolfTaylor]

A few points to consider (not specific to Barix)

1) Independently confirm the quality of the link by using the DOS ping command with the -t option enabled:

>ping 123.456.789.102 -t

Or better yet, download the colasoft ping tool here: http://www.colasoft.com/products/freeware.php?c=b

You should see virtually no failed ping responses in 24 hours time.

2) Determine the packet size being used by the Barix box. You may be having problem due to exceeding the MTU (Maximum Transmission Unit) setting of the transmission gear. If this is the problem you will need to increase the MTU or reduce the packet size.

3) Try using analog I/O and see if the problem goes away. AES/EBU requires synchronous connections or very sophisticated clock-over-IP schemes. If this solve the problem see what Barix has to say about the problem.

And congrats for choosing 32 kHz for the sample rate. A common mistake is to use a higher sample rate and forcing the codec to operate a a higher compression ratio (or simply flood the network with more packets). 15 kHz is good enough for FM.

Best of luck.

 

[duckfan98]

Hi Rolf,

I am only using AES from the automation computer, into the mixer console. I am then going out (PGM1) of the console using standard L/R analog audio. Is that an issue???

 

[chriscollins]

And congrats for choosing 32 kHz for the sample rate. A common mistake is to use a higher sample rate and forcing the codec to operate a a higher compression ratio (or simply flood the network with more packets). 15 kHz is good enough for FM.

Best of luck.

True... On the Comrex boxes, I prefer FLAC 15K. It sounds smooth and keeps the data rate low.

 

[oldiesstation]

I have a pair of barix 500's running pcm on a ubiquiti link nanostation m5.almost 2 years now,no issues at all.i wasn;t even aware the 100 would do pcm...not sure what's going on there.does the 100 have the latest firmware? i think the issue is in the Baris settings,not the link.Plenty of pipe there.

 

[oldiesstation]

are you running the Barix STL software or client streaming? you should be using stl software.

 

[RolfTaylor]

Sorry, my bad. Ignore that particular point

Hi Rolf,

I am only using AES from the automation computer, into the mixer console. I am then going out (PGM1) of the console using standard L/R analog audio. Is that an issue???

 

[duckfan98]

are you running the Barix STL software or client streaming? you should be using stl software.

I am running the latest STL firmware on both ends....

PCM (stereo, any option in encoder side) creates nasty garbled, robotic like noises - followed by frequent signal loss....

 

[oldiesstation]

do you have clear line of sight?? NO TREES in the way.I had that problem,worked fine until strong wind or rain.problem ,had to move the radio up the tower.i know that sound very well.when the trees are dry everything worked fine.when those leaves get wet it attenuates your signal.robotic noise and signal would drop way down .now i'm convinced it's a radio issue.

moved the radio up 50 ft,problem solved.i was only going thru the tops of a couples of trees and just 1000 ft stl distance.figure that out.2.4 is more forgiveing than 5.

 

[Kmagrill]

Just out of curiosity, does the path work if you use some mp3 compression like 128k?

 

[stephend2]

I have had 0 luck getting 32khz PCM working on barix 100 units. 44.1 seems to work fine.

check your buffer settings in the exstreamer, if its too small it could cause exactly the issue you are reporting.

I'm providing transport for a couple radio stations through our wireless network (all ubiquiti) through multiple links and routers without issue.

The barix units can be tricky to configure.

 

[duckfan98]

Hi.

ALL MPEG compression works. Just wont do PCM....argh!

As far as the buffer goes, I have it set to 600. Do you recommend even more?

 

[chriscollins]

Have you tried Stephen's suggestion of going to 44.1 and seeing what happens? I would do buffer at 999.

 

[Kmagrill]

Start with the buffers as big as possible. Barix receivers have a 64k buffer which is only a fraction of a second at PCM data rates. Not sure about the encoder, but generally bigger buffers = more resilience.

 

[oldiesstation]

agree chris.now i recall the issues stephen had doing 32. He is a Barix whiz, wireless expert and a dam good engineer.I went with the Barix 500's.my issue was line of sight.