QSC K 10.2

Guilty Party

Guilty Party

Member
Hi All.

Maybe this has been asked but I have a situation, so if I am annoying any users just pass me by.

Looking to amplify/ monitor my FM9 for medium sized rooms. Kinda made the decision to go FRFR for now to try and stay in the IR game. Maybe that will change over time. Where I live there is supply on common brands of PA gear but nothing really designed for guitar, if that is even a thing. Lots of folks say PA speakers are just fine, some don't and I am not here to debate that. I just can't try a Xitone or RCF out without ordering one. Sight unseen (unheard) doesn't tickle me. At least if I buy local it can be returned if not satisfied.

What I did:
A/B demoed QSC K 10.2, Mackie SRM 210. Yamaha DXR 10, Yamaha DHR 12M. Side by side, same room, same preset. Same everything. QSC sounded best to me. Oddly, though, it went into a Protect Mode 4 during the demo. I didn't know the full story at the time and ended up taking a boxed one home. I did read at home about all the issues people have had with the K.2 firmware, etc. I also read a firmware log that indicated the problem was resolved, my firmware version is the newest so I figured I'm fine.

Did a gig and a couple rehearsal with it, went fine.

Then, at my last session, it went into a series of Protect Mode episodes. 3 times over 2 hours.

I emailed QSC support and started a case and explained the details. They responded promptly I might add, and told me to check my output level on the FM9. Now, I set it up initially, but I am a newer user so maybe I am doing something wrong. Here's what they said:

"We're seeing that with the new firmware 1.4.1 and 1.5.5 this protect mode false trigger is solved. So i will recommend that you check about your gain structure coming out from the FM9. you can configure it as the user manual recommend. Try to be more careful with the output on your FM9 because the protect mode is telling you that the audio source signal is coming in too loud. Run some audio tests after you configure your FM9 levels and let us know if the issue persists. Have a great day!"

Here are my settings:

Setup/ Audio - Output 1 set to Stereo (I typically only run a mono output to a monitor live). Also set to +4dBu
Out 1 block level set to 0
Amp block level set to 0 (I do notice that most factory presets trim that level to (+/-) -10dB so I am running hotter here)
No Drive block, no
The QSC level is at unity and there is no DSP, EQ or HPF engaged. Set flat

I'm having a hard time buying that my settings are erroneous at all or are enough to cause the Protect Mode 4 shutdowns. QSC is basically saying that the speaker is still sensitive to processing a slightly hot signal and that I will need to be mindful of such. Seems goofy to me. I just don't see any settings that are over the top or out of line.

Given the history of the issue with QSC and the fact that I have 2 weeks of return policy left I am inclined to return it rather than risk an ongoing, tiptoe scenario. I guess my reluctance to do so is that I love the sound, it works for me.

If anyone has thoughts on the situation or perhaps thoughts on other settings that I may be overlooking that would be appreciated.
 
Guilty Party said:
Amp block level set to 0 (I do notice that most factory presets trim that level to (+/-) -10dB so I am running hotter here)
Click to expand...
0 is pretty hot so I'd reduce it. When leveling factory presets we typically adjust the Amp level to set the average output at 0 dB according to the Preset Leveling tool, with minor temporary peaks just barely above it. That results in the Amp block's Level somewhere below 0 dB, where some are much lower than -10 dB and others are -4 dB-ish, it depends on the model.

It's not clear where your FM9 OUT 1 knob is set on the front-panel, but if it's full on, and at +4 dB you could be sending 14+ dB. I don't remember exactly how much digital headroom the unit has but you might be getting digital clipping and the speaker's software is sensing it and shutting down. Clipping that signal can overheat a speaker, which, in engineering vernacular is called "bad". They're good with words that way. :)
 
Hey Greg.

Thanks for your comments, they are duly noted and appreciated.

I don't think I have ever had the OUT1 knob past half and typically it is set at around 10 o'clock. I also never have seen the output Clip Indicator on the FM9 illuminate. I hear what you are saying and I will adjust my user preset amp levels and give it a try. I guess what I hear is this:

If I am too hot either by a block (amp, etc) level or by cranking up Out 1 level then I run the risk of continuing to have issues.
If I want more volume than I am getting with these factors reigned in, then it's a better bet to turn the speaker itself up while keeping the FM9 gain staging moderate.
 
I agree with Greg. I have a FM3 and am waiting for a 9. My FM3 goes into my mixer then into my Focusrite interface into my Mac. With the channel and output of my mixer set to 0( unity), I can't get the amps blocks volume more than -10. I use mostly Marshall type amps. Any higher I clip the inputs of my interface. 0 would be way too hot. I am pretty certain that is the source of your problem.
Keep us posted as I am interested in the QSC K10.2
 
The QSC issue is a known issue that went unresolved for quite some time so I wouldn't be inclined to believe they have fixed the problem. Many many threads on gear page with many many attempts by users to get QSC to resolve to no avail...
 
There are still serious reliability concerns in the Pro Sound community over protection shutdowns.

It looks like they got an entirely new chipset for manufacture dates on or after Sept 5th 2022. And firmware 1.5.5 to support the new DSP.

If your firmware is 1.4.1 or earlier, I would consider returning them, as they cannot be updated to the the new firmware.

Here are the release notes:
https://www.qsc.com/resource-files/productresources/spk/k.2/q_spk_k2_firmware_updates_log.pdf
 
Greg Ferguson said:
+4 dB is the appropriate setting for "professional" gear, so that part is understandable. From p. 95 in the manual:
Click to expand...

Understandable. But, the QSC manual itself does not specify their input specs like some other products do which is why I posted the above. The voltage references are different between these settings. I'm not saying it "should" work this way. I'm asking if you tried it since the QSC tech reply seems to indicate the problem is with the input gain staging.

Side note, I'd probably return these too. It doesn't sound like they have this problem fixed. And it's entirely possible they are trying to mask a hardware defect with firmware.
 
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Hi -- I have used a complete QSC PA system for many years without any issues with mains and monitors. I use K10s for monitors. In all the years I have been using the fractal -- Most of my amp blocks are set between -8 to -21+ input around 10. I set the QSC to flat and line.
I hope this helps.
 
Marioverkill said:
I agree with Greg. I have a FM3 and am waiting for a 9. My FM3 goes into my mixer then into my Focusrite interface into my Mac. With the channel and output of my mixer set to 0( unity), I can't get the amps blocks volume more than -10. I use mostly Marshall type amps. Any higher I clip the inputs of my interface. 0 would be way too hot. I am pretty certain that is the source of your problem.
Keep us posted as I am interested in the QSC K10.2
Click to expand...
I will be running at
Flatnine said:
The QSC issue is a known issue that went unresolved for quite some time so I wouldn't be inclined to believe they have fixed the problem. Many many threads on gear page with many many attempts by users to get QSC to resolve to no avail...
Click to expand...
This is the concern about getting "stuck" with one. When is the last time we saw a speaker go into a shutdown mode repeatedly with a level that I think we have determined is a bit hot? Ever?
 
Old News said:
Hi -- I have used a complete QSC PA system for many years without any issues with mains and monitors. I use K10s for monitors. In all the years I have been using the fractal -- Most of my amp blocks are set between -8 to -21+ input around 10. I set the QSC to flat and line.
I hope this helps.
Click to expand...
My findings are that the older K10s are typically fine, it is the newer 10.2 that has become the issue. My QSC is set to line and flat as well. My ampp block is a bit hot and my Out 1 is usually at 10-11 o'clock. When you say your input is around 10, what does that mean?
 
WKSmith said:
There are still serious reliability concerns in the Pro Sound community over protection shutdowns.

It looks like they got an entirely new chipset for manufacture dates on or after Sept 5th 2022. And firmware 1.5.5 to support the new DSP.

If your firmware is 1.4.1 or earlier, I would consider returning them, as they cannot be updated to the the new firmware.

Here are the release notes:
https://www.qsc.com/resource-files/productresources/spk/k.2/q_spk_k2_firmware_updates_log.pdf
Click to expand...
Mine is running the new chipset and version 1.5.5 firmware. The latest. That's why I thought I would escape the issue. Now, will it make the difference to trim the amp levels back 10dB and maybe run at -10 dBu vs +4 dBu? I can try but that feels a bit like a tiptoe to me. As in, better be careful with your level or the QSC will shut down in the middle of a set. Hmmm...
 
I guess this last comment is for everyone watching. If it is the input level to the QSC causing the issue, then the output level of the speaker should have nothing to do with it? So I should be able to recreate the fault even at bedroom volume?
 
There is a huge thread on TGP about this. The issue seems to be centered on the 10.2 speakers. I have been following that thread a bit because all of my PA speakers are QSC K series. I have the first version, a couple of pairs, and one pair of the K8.2 speakers for monitors. I have never had any issues with any of mine. From what I have seen, the only ones that have been permanently fixed have been taken to a service center and had the entire amp section of them replaced. This is directly related to what was said above. I would return it or you are probably going to end up in a long chain of emails and calls that result in taking it to a service center for an amp replacement.
 
Guilty Party said:
I guess this last comment is for everyone watching. If it is the input level to the QSC causing the issue, then the output level of the speaker should have nothing to do with it? So I should be able to recreate the fault even at bedroom volume?
Click to expand...
Thanks for the head's up. Two of my friends have been using QSC for years with no problems but they may have the older versions. When you adjust the level on a power amp or powered speaker, you are usually adjusting the input and the output is usually hardwired "wide open" so to speak. You probably won't be able to reproduce it at low volume. I have not seen a schematic of the QSC so I may not be 💯 correct on that though..
 
Guilty Party said:
If it is the input level to the QSC causing the issue, then the output level of the speaker should have nothing to do with it? So I should be able to recreate the fault even at bedroom volume?
Click to expand...
I'd assume so, IF the volume control of the speaker isn't actually reducing the input coming from the modeler, but instead is reducing the speaker's amp's output. Without knowing how it's wired it's hard to say.

PS - looking at their manual, on p. 10, for their design, the line input hits an amplifier which is followed by the Mic/Line Gain control, so if you hit that input too hard it's going to distort and you can't do anything about it except send less signal to the speaker.
 
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The lack of clarification from the QSC engineers is a serious problem. +4dB is exactly 1.228 volts RMS.

But there is no documentation or guidance as to what triggers the protection. (Even for industry pros)
Many power amps have a 1.5V limit (seriously several) to trigger over voltage protection from the inputs.

But the QSC also (purportedly) detects clipped waveforms. Alien artifacts? Subliminal thermal messages?
I would send that thing back and try something else.
 
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Some interesting thoughts, thanks people. I am gonna do the following:

Make my retailer aware that an issue exists. He's actually our drummer, so... Explain my proposed resolution plan so that if a fix doesn't happen, retailer may have some grace on satisfaction guarantee/ time period of 30 days.

Reset any amp block level changes i have made

Try the changes both at bedroom level and stage level

QSC is obviously pro gear so I don't feel that I need to run at -10dBu. Agreed?

By dialing down amp block level, I will then need to turn Out 1 up to get to the same volume. Or should I be turning up the QSC volume.

It all seems kinda goofy but I am willing to run the tests.
 
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