Questions & Answers

My presonus NSB cuts all audio all time and needs to be power cycled to get audio back. Why? These are brand new

+1 vote
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asked Aug 25 in Networked Stage Box by bobbybutcher (210 points)
I have tell presonus NSB 16.8 digital snakes I use with a cat 5 cable. About 2 weeks in from owning these they would randomly cut out and I would lose all audio/connection. I would have to power cycle then I would get audio. I thought maybe they are overheated so I would shut them off when not using then on when we use them (2 times a week about 4 hours each time)
This sunday they cut out after 2 hours mid service. Firmware up to date and still have the issue. Beyond frustrating after spending all this money for the equipment not to work properly. We also get the random audio cut outs in and out like every 30 seconds as well. Brand new presonus studiolive 32 mixer.

Any thoughts? I searched the forums and saw no solutions.

3 Answers

0 votes
answered Sep 12 by jonnydoyle (211,740 points)
 
Best answer

Please ensure you have them setup correctly. 

2 Stage Boxes:

Ensure your cabling is correct. 

https://support.presonus.com/hc/en-us/articles/360031841952-Ethernet-Cables-for-AVB-Guide

0 votes
answered Aug 25 by wahlerstudios (78,050 points)
Don't worry, there is nothing wrong with your equipment. Dropout means network/rouiting and clocking problems. Do have two AVB streans assigned to each stagebox and one from each stagebox? Do you always start the mixer first? What are your input channels? Which stagebox delivers which inputs? Which aux mixes have you assigned to which stagebox? From which stagebox do you take Main l/r?
0 votes
answered Sep 14 by juergenboehme (450 points)
edited Sep 14 by juergenboehme

Well …

I see a similar issue with my NSB (also dropouts with a StudioLive 16) and I’m in contact with the support for this. After all I found a workaround for me but support says that this is not the way a Presonus product should work. They want to have a look at it. Issues like this should not be present at all NSB’s. But at some it might be possible.

So please don’t worry, check some things, and if nothing works confidentially then open a ticket to let your box check from a Presonus technician. Yes, even if it’s new. I don’t know the exact issue but if they can help then I will be fine with it.

During the last weeks I learned something about  this simple looking network connection on the back of my mixer: It is not a simple looking network connection. It has an Ethernet connector but it carries something very sophisticated and special: AVB.

AVB means Audio Video Bridging. This is a protocol, something which travels over the network cable and carries content. Not only this, it is possible to define targets. This is called “routing”. You have only one cable from the mixer for all the audio signals, and you can direct one audio signal to stagebox 1, the next one to stagebox 2, the third one to a specific channel on an Earmix device.

The normal audio would only run over the cable from one end to the other without knowing where to go then. This is called “point to point”. This means that a signal which you can route to a specific target carries more digital information than just a point to point signal. Like a letter you put into an envelope and write an address on it so that the postman knows where to deliver. Result: Same audio signal like on a point-to-point connection but more data traffic.

Additionaly at the same time like audio the AVB protocol can also transport video content. Not only this, the different signal types can also have different clock rates at the same time on the same physical cable. It’s like a Big Mac. From the outside you see one single Big Mac, but from the inside in can consist of different layers of meat and bread and tomatoes.

Next thing:

Some people are happy with these compressed MP3 audio files. You can use them even on a slow internet connection. Not with this signal here. Lots of incoming channels, lots of outgoing channels, all in up to 48 kHz and 24 Bit resolution. This is heavy duty. Do you know these lovely small plastic network hubs for home use? Compared to this the Presonus AVB switch looks like a monster truck with a solid metal chassis and some cooling profiles on the back. Maybe it is designed to operate at a temperature where those lovely little plastic hubs might burn a little bit.

Next thing:

There is also the term AVB/TSN. TSN means “time sensitive networking.” The standard is that the signals are delivered over the network within a maximum time of 2 milliseconds. All the channels with all the routing and all the uncompressed audio. So quite fast, about no delay from input to output over the complete network. There is time information added to the digital signals to make this happen, and all the components in the network are communicating all the time to make sure that each single portion of audio reaches its target within 2 milliseconds. If one part in the network has a reduced capacity sometimes for some reason it is communicated and the audio takes a different route to be at the target in time. Perhaps you know Skype or other Voice-over-IP applications where it is common that you talk into the microphone and the audio reaches the audience one or two seconds later. In AVB this is realtime, on the monitor you can hear what you sing without delay.

The normal TCP/IP traffic in computer networks doesn’t have this additional time information. It uses the same type of physical cable connection but the transported signals have a quite different technical background.

Why do I refer to this?

You mentioned that you are using a Cat 5 cable. Cat 5 is used for 10 or 100 Mbit network connections. Because of the huge amount of data in an AVB network as the minimum you should use Gigabit network connections. This is Cat 5e or Cat 6. They are designed for this kind of traffic.

Recommendation: If Cat 5 was not an accidential typo in your post then please organize Cat 5e cables for you and check again.

There are additional differences. Normally you would get a shielded cable (another aluminium shield around the cores under the surrounding plastics). When deliviered from Presonus there comes a blue network cable with the mixer. The specification is “CAT 6 UTP TIA/EIA-568-B”, UTP is "unshielded twisted pair". The shield might cause signal irritations on the AVB data if not manufactured with high precision. Shielded cable is marked as "CAT 6 STP".

In case you want to contact support they will ask you to perform some tests with exactly this blue cable because it has a verified specification. Please look back to the amount of data which is transported. It is important which type of cable you are using.

On the other end there are cables with a higher specification, CAT 7.  AVB is designed to work with CAT 5e or CAT6, CAT 7 is for 10 Gigabit datatransfer and above. A technician would say, a cable is a cable and a digital information is a digital information. But I noticed a difference in the high frequencies, a more detailed representation. Of course the bass frequencies got also more detailed and the Cat-6-sound had a little bit more deepness first. I could correct this with the EQ. But it was not possible even with EQ correction on the Cat-6-cable to get  the sound of the CAT-7-cable in the high frequencies. Might be just my personal impression but to me it sounds more natural, more open. Might depend on the sort of music you are playing, but I would say, give it a try, listen if you hear a difference and decide if you like it. Technically CAT 6 should be fine, but maybe the personality of the signal says “Oh, there is some unexpected extended space on this CAT-7-cable, let’s see how the world would look like if I would fly a little bit higher …”

I had a similar experience with a firewire connection between my Tascam FW1884 interface and my computer. There is the company Oyaide with their NEO d+ cable series (http://www.neo-w.com/english/products_en/studio_producer_en). High quality cables, and I noticed a different sound atmosphere compared to my normal firewire cable on the digital connection. A real technician will call you crazy, 0 is 0 and 1 is 1. Don’t discuss it, just check it out and decide for yourself if it would make a difference for the way you prefer to work.

At last now the workaround which made my mixer operation more stable.  Of course the result is that I can’t use the first eight AVB channels that can be addressed for the input streams from the stagebox to the mixer. If you need them then this workaround is not for you. I shifted my configuration to use channel 9-16 for the first eight connectors on the NSB 16.8 and 17-24 for the second eight connectors. Please consider if you do a configuration reset the normal standard is 1-8 and 9-16. You can store this in the scenes but after a reset it will not be there first.

When you press the home button on the mixer you come to a screen where you can select “System”. There you can set the mixer clock either to “internal” or “network stream”. Besides this there is a network indicator. In standalone operation of the mixer this indicator is grey. It remains also grey when you connect just an EarMix on the network connection. I never had any dropouts when listening to audio just on the EarMix and no other network devices connected.

The indicator becomes green when you connect a NSB to the network port, route the NSB-inputs to the outputs to activate AVB synchronization and select 1-8/9-16 as input streams. So there must be something different compared to the network connection to an EarMix (no green indicator).

I found an explanation in the AVB network manual from Presonus, section 2.7.1, “Wordclock”. An AVB network can support different independent Wordclocks. Presonus AVB devices identify a clock signal by listening on the first stream.

I thought if the earmix is operating fine without this clock indicator, what would happen if I would try also AVB incoming streams without this clock listening because there are no different clock signals available I need to care for.  So I tried not to use the first AVB stream . This can only be reached by setting the NSB to use the input streams 9-16/17-24 for the 16 channels. Result: The indicator stayed grey/inactive.

Additionally I recommend the use of the Presonus AVB switch for a stable operation. You can either daisy chain your equipment (network cable from mixer to the first stagebox, from there to the next stagebox, from there to the first Earmix and from there to the next Earmix). Or you can choose a star configuration (mixer to switch and from there one cable to each device, no daisy chaining).

The switch is not only splitting up one incoming signal into four outgoing signals. The switch is also an active network component which takes special care that all the outputs are properly synchronized to the input and that the signals reach all their targets within the time of 2 milliseconds.

Therefore I have started using the switch always even if I connect the mixer just to one stagebox and do not use any other network equipment.

Result: The NSB was working without any dropouts for hours.

What I noticed on the active clock indicator that it sometimes switched from green to red and back to green. Around this colour changes often dropouts appeared. So maybe somewhere in this area there is a synchronization issue and maybe also the reasons for the dropouts before. Maybe the hardware is fine, and there is an issue with the protocol itself. I don’t know, we will see what happens in the future.

Of course on a higher system load it might be necessary for a stable operation to have this monitoring active. Therefore I will let the Presonus technicians check my NSB to be prepared for what may come in future.

But at the moment I’m also a happy Presonus user with some high quality equipment which is working fine. So it’s worth to put some effort into finding out the reason for a specific situation.

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