Presonous 24.4.2 going full gain suddenly

Greg Cameron

Greg Cameron

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Jan 11, 2011
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Hello folks. I have a friend locally that provided sound for a smaller stage at our local Celtic Festival last summer. Yesterday he mentioned an issue where a couple of time during one of the days where the gain on his 24.4.2 jump to full blast suddenly for no reason. He couldn't tell if it was channels or master bus, but pulling down the main mix didn't stop it. Happened once during music playback between performers, then once during a performance. His hands were not on the desk when the gain jumped. Needless to say, he was mortified along with the audience and artist. He switched to his backup desk, a Presonous 16.4.2 to finish out the weekend. I've advised him to update the firmware to the latest. He said he had done no firmware updates since purchasing the desk a year and a half ago. He was also not using the firewire interface, I know that has caused problems if the cable comes out during a show. Anyone else run into this issue?
 
Re: Presonous 24.4.2 going full gain suddenly

Greg Cameron said:
Yesterday he mentioned an issue where a couple of time during one of the days where the gain on his 24.4.2 jump to full blast suddenly for no reason. He couldn't tell if it was channels or master bus, but pulling down the main mix didn't stop it.
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Those have manually operated preamp knobs don't they? By "gain" are we talking about the preamp, or a gain control somewhere else?

Chris
 
Re: Presonous 24.4.2 going full gain suddenly

That's a good question Chris. He doesn't know where in the gain path that jump in gain came from, but you make a good point. If the preamp gains are analog with standard pots, a bad ground connection could allow the preamp to go full tilt boogie. I've seen that happen on channel faders before. The board has had very little use since it was purchased. But my understanding is that most of the malfunctions on those desks are due to glitchy firmware. Glad it's not mine.
 
Re: Presonous 24.4.2 going full gain suddenly

I recently had a bad experience with losing 10dB all of a sudden. As if a compressor suddenly kicked in or..

It was being used for DJ's between bands; only 2 lines in; both of them appeared to be metering the same (no drop) but master outputs dropped.

And then it would suddenly come back. We had no compressors or inserts etc in the processing.

Main faders also had a severe lag - move them and count a second or so and THEN hear the results.

We ended up using 2 aux busses and avoided the main bus and that seemed to work but..

I mention this in case there is some kind of digital fault. Full blown audio / -10dB could be the same kind of issue.

Andrew
 
Re: Presonous 24.4.2 going full gain suddenly

Greg, et al...

I would request everyone posting reports of digital console glitches to include the power source and the presence or absence of line voltage regulation. This in addition to a thorough assessment of the firmware will help in the long run. IM(limited)E, voltage sags, spikes or fluctuations do seem to affect digital gear performance. I first encountered it while using a MIDI rig for performance and I suspect that voltage variations can masquerade as "commands" in the digital realm.

Or not...

DR
 
Re: Presonous 24.4.2 going full gain suddenly

The studiolives have a tendency to get its flash memory corrupted at times and it may take several power cycles before any actual errors show up.

Unfortunetly it is common practice to reload the firmware and restore to factory settings every now and then. Faliure to do so when errors begin to show may render the console unable to boot eventually and need to be serviced at presonus.

Unlike many other devices the studiolives doesn't have any failsafe boot.
 
Re: Presonous 24.4.2 going full gain suddenly

Robert Lofgren said:
Unlike many other devices the studiolives doesn't have any failsafe boot.
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Well that's pretty bad. All the devices we make at my day job have a safe boot firmware image in the event the main image gets hosed. That way you can at least hobble along and get into the system to reload the main image as well as check the failure logs, etc.
 
Re: Presonous 24.4.2 going full gain suddenly

Greg Cameron said:
Well that's pretty bad. All the devices we make at my day job have a safe boot firmware image in the event the main image gets hosed. That way you can at least hobble along and get into the system to reload the main image as well as check the failure logs, etc.
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The problem isn't so much the boot loader but the fact that it reads the comfiguration data from the corrupt flash.

The studiolive has two cpu's one is the arm-based sharc dsp and the other is some 8051 derivate.

The sharc is responsible of the firewire interface but it has no program flash memory. Its program only loads and run in ram. The other cpu has the flash memory that also contains the sharc code. When the sharc bootloader starts it awaits the second cpu to download its code via spi. This also configures the firewire interface.

The second cpu now wait for confirmation that the sharc has fully booted. When the downloaded code is executed on the sharc it tells the second cpu that it's now ready to service.

If the sharc code and configuration data is corrupt the firewire interface will never work and there is no way for a normal user to re-flash the memory and restart from fresh :-( the second cpu will wait forever on its sharc friend...
 
Re: Presonous 24.4.2 going full gain suddenly

Robert Lofgren said:
The problem isn't so much the boot loader but the fact that it reads the comfiguration data from the corrupt flash.

The studiolive has two cpu's one is the arm-based sharc dsp and the other is some 8051 derivate.

The sharc is responsible of the firewire interface but it has no program flash memory. Its program only loads and run in ram. The other cpu has the flash memory that also contains the sharc code. When the sharc bootloader starts it awaits the second cpu to download its code via spi. This also configures the firewire interface.

The second cpu now wait for confirmation that the sharc has fully booted. When the downloaded code is executed on the sharc it tells the second cpu that it's now ready to service.

If the sharc code and configuration data is corrupt the firewire interface will never work and there is no way for a normal user to re-flash the memory and restart from fresh :-( the second cpu will wait forever on its sharc friend...
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Thanks I can actually understand that... It seems like such an error could be anticipated with an error check in software to confirm that it is receiving valid data. Of course there is always some slender chance that the corrupt data will check Ok, but very unlikely. If it sees that it is receiving bad configuration data, it could default to a safe mode. At some point if the serial communication is not working properly, it needs to give up.

JR
 
Re: Presonous 24.4.2 going full gain suddenly

John Roberts said:
Thanks I can actually understand that... It seems like such an error could be anticipated with an error check in software to confirm that it is receiving valid data. Of course there is always some slender chance that the corrupt data will check Ok, but very unlikely. If it sees that it is receiving bad configuration data, it could default to a safe mode. At some point if the serial communication is not working properly, it needs to give up.

JR
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The problem in this case is that there's only one flash memory and that the critical partitions can get corrupt.

As you are probably aware of most "consumer" switching psu's, while able to deliver 4 Amps continously, can't normaly handle 4 Amps as transients.

Now, let's imagine that the power rail is construced as mains-->5v-->3.3v-->1.8v. This means that the 1.8v derives its power from the 5v feed. Those power rails are responsible for all digital stuff including mcu, dsp, flash memory, etc...

Now, imagine all those fancy christmas lights that you find on the sl24 that is connected to the 5v rail and what happens when all leds turns on at the same time.

Do I need to say more ;-)
 
Re: Presonous 24.4.2 going full gain suddenly

I can't speculate intelligently about their PS robustness. Generally a 5V rail can sag quite a bit before 3.3V and 1.8V rails crap out.

If LEDs are multiplexed (more speculation), they aren't all on, even when on... While I might be tempted to not multiplex LEDs near any sensitive audio paths.

JR
 
Re: Presonous 24.4.2 going full gain suddenly

All Presonus SL models are prone to this. They have the world's crappiest faders, and they just let go (at the most inconvenient times). The inputs to the ADC multiplexers which the faders drive are such high impedance that the channel with the open fader can be influenced by its adjacent neighbours. I did 2 last week - same fault. The good news - the faders are cheap (around $30 for a bank of 7 from Presonus).
M
 
Re: Presonous 24.4.2 going full gain suddenly

Andrew Broughton said:
What is your evidence of this?
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I had a lot of trouble with MIDI devices spontaneously changing patches with varying voltage. Once I got a 1215 to regulate the voltage I had ZERO problems with the MIDI devices changing settings unbidden. That is what makes me suspicious.
 
Re: Presonous 24.4.2 going full gain suddenly

Dick Rees said:
I had a lot of trouble with MIDI devices spontaneously changing patches with varying voltage. Once I got a 1215 to regulate the voltage I had ZERO problems with the MIDI devices changing settings unbidden. That is what makes me suspicious.
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I hear what you're saying, and I don't dispute you had issues, but as a "MIDI guy" I don't see how that could be directly possible. What did you have connected, what was controlling what?

In interests of not derailing this thread too much, perhaps we should start a new one.
 
Re: Presonous 24.4.2 going full gain suddenly

Andrew Broughton said:
I hear what you're saying, and I don't dispute you had issues, but as a "MIDI guy" I don't see how that could be directly possible. What did you have connected, what was controlling what?

In interests of not derailing this thread too much, perhaps we should start a new one.
Click to expand...

Nah, I don't need to re-hash all that stuff. Suffice to say that there WAS an accordion involved...
 
Re: Presonous 24.4.2 going full gain suddenly

Dick Rees said:
Nah, I don't need to re-hash all that stuff. Suffice to say that there WAS an accordion involved...
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The only reason I brought it up is to avoid spreading incorrect advice. You were suggesting that MIDI commands could be sent if there are power fluctuations. I don't believe that to be true, so it's important that we confirm the facts and the right information. If you were not saying that, then I misunderstood. I don't care if we try to solve this now, I just want people reading to get the best advice possible and as much correct information as they can.
No offense intended towards you, but the pro audio world is already far too full of rumours and opinions masquerading as facts.
 
Re: Presonous 24.4.2 going full gain suddenly

Andrew Broughton said:
The only reason I brought it up is to avoid spreading incorrect advice. You were suggesting that MIDI commands could be sent if there are power fluctuations. I don't believe that to be true, so it's important that we confirm the facts and the right information. If you were not saying that, then I misunderstood. I don't care if we try to solve this now, I just want people reading to get the best advice possible and as much correct information as they can.
No offense intended towards you, but the pro audio world is already far too full of rumours and opinions masquerading as facts.
Click to expand...

Check your PM's for the info on midi.

I always recommend anyone using digital to incorporate voltage regulation in their FOH gear...
 
Re: Presonous 24.4.2 going full gain suddenly

Have the Firewire interfaces ever been used before this? We have a couple sl 16.4.2's at my school. Connected via firewire. We've been having some weird problems with them lately. After much investigation with them, sending one back for repair (and receiving a new one in return), then having the new one go out the first time it was used, we found out that the firewire card in the one that had never been sent back was bad. Apparently when they go in those things, they mess up more than just the firewire, and have the capability to mess up other consoles. When we connected them together, it corrupted the new one, and now whether you connect them or not, it goes out after about 20mins. Signal just stops registering, main output meter goes to halfway and just stands there until console is restarted, then promptly goes through the same thing again. Tried updating the firmware in both of them, doing resets, and everything else. Just saying, if your problem persists, it may be something to look at.
 
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