QSC K12 problem - Updated!

[Spirits High]

Gigged last night for the second wedding of the year and one of the K12s has gone a bit "Pete Tong"

Did the usual sound check etc and one side sounded and was alot quieter than the other. All settings on both speakers were the same, so changed the xlr, still the same. I tried both outputs on the speaker and same result.

For those unfamiliar with the K12 there's a mic or line switch on the left input so I thought I'd see if this made a difference so the gain was turned right down flicked the input to "mic" and gradually increased the gain. This made the speaker output sound the same as the other side :confused:

I ended up doing the whole gig with it in "mic" mode.

Any ideas folks?

They were bought from Thomann last July so still in warranty. I'll be emailing them later to see what the score is.

[leelive]

Gigged last night for the second wedding of the year and one of the K12s has gone a bit "Pete Tong"

Did the usual sound check etc and one side sounded and was alot quieter than the other. All settings on both speakers were the same, so changed the xlr, still the same. I tried both outputs on the speaker and same result.

For those unfamiliar with the K12 there's a mic or line switch on the left input so I thought I'd see if this made a difference so the gain was turned right down flicked the input to "mic" and gradually increased the gain. This made the speaker output sound the same as the other side :confused:

I ended up doing the whole gig with it in "mic" mode.

Any ideas folks?

They were bought from Thomann last July so still in warranty. I'll be emailing them later to see what the score is.

Hate to state the obvious... but did you swap the stereo connections to see if it was the signal. Try the line out in the other speaker to see.

Sorry I have no other thoughts.

Lee

[Spirits High]

Hate to state the obvious... but did you swap the stereo connections to see if it was the signal. Try the line out in the other speaker to see.

Sorry I have no other thoughts.

Lee

Yep, did that too!

[Excalibur]

Hate to state the obvious... but did you swap the stereo connections to see if it was the signal. Try the line out in the other speaker to see.

Sorry I have no other thoughts.

Lee

You may be onto something here. Paul says he swapped the XLR cables, but I'm assuming he kept the mixer outputs the same. Lee is suggesting not swapping the cables, but swapping the outputs at the mixer end, and seeing if the quiet channel changes sides, thus implicating the mixer as the culprit.

As I'm typing this, I'm thinking has the balance fader been altered without realising? That would give the symptoms described. Also, check the mixer with the backup PA, and see if the fault is there with this one. Elimination.

Edit: Not typing fast enough.

[Spirits High]

After a morning of testing & swapping things around I think it's a speaker problem :(

Thomann were on the ball as expected and it gets picked up tomorrow morning and off to be checked over repaired etc.

I'll let you know what the problem was when I do.

[Spirits High]

As an update. The speaker is now on it's way back from Germany.

The fault? They can't find one!

Here's there reply:

I can confirm that a number of tests were carried out that show that the speaker is working within its specification including SPL db levels and for thermal issues so the problem must be elsewhere.

I do have one suggestion though, can you tell me the serial number of the other speaker as a difference in volume could be related to a change in manufacture and if you have two mismatched speakers then this could be a possibility.

I will have this checked with the service partner, it is a long shot but I cannot think of any other reason at this time.

So I'll fire off the serial number of the other speaker and as he said it's a long shot but you never know.

In the meantime it's back to the drawing board so to speak. :confused::confused:

[MikeW]

As an update. The speaker is now on it's way back from Germany.

The fault? They can't find one!

Here's there reply:

I can confirm that a number of tests were carried out that show that the speaker is working within its specification including SPL db levels and for thermal issues so the problem must be elsewhere.

I do have one suggestion though, can you tell me the serial number of the other speaker as a difference in volume could be related to a change in manufacture and if you have two mismatched speakers then this could be a possibility.

I will have this checked with the service partner, it is a long shot but I cannot think of any other reason at this time.

So I'll fire off the serial number of the other speaker and as he said it's a long shot but you never know.

In the meantime it's back to the drawing board so to speak. :confused::confused:

You have got my sympathies on that one. There is nothing worse than a sound problem that can't be solved. Hope you get it sorted asap.

[Excalibur]

Not the outcome you were hoping for. Have you tried another playout/mixer for elimination purposes? My money was on a rogue balance control, or crossfader, but it appears you've ruled that out.

Here's something you could try, to either confirm or disprove Thomann's findings. Plug one speaker into your mixer, and then rather than connecting the second one to the other side, daisy chain it to the first one. If there's a noticeable/audible difference between the two, then Thomann's findings must be in doubt. If they're identical, then the problem's in your mixer/playout.

[funkymook]

Maybe it's the louder speaker with the problem?

[Spirits High]

Not the outcome you were hoping for. Have you tried another playout/mixer for elimination purposes? My money was on a rogue balance control, or crossfader, but it appears you've ruled that out.

Here's something you could try, to either confirm or disprove Thomann's findings. Plug one speaker into your mixer, and then rather than connecting the second one to the other side, daisy chain it to the first one. If there's a noticeable/audible difference between the two, then Thomann's findings must be in doubt. If they're identical, then the problem's in your mixer/playout.

I've yet to receive the speaker back from Thomann yet but thought I'd try the daisy chain theory with the back up system that will probably be out over the weekend.So I'm able to cut the mixer from the equation.

Daisy chained together sounds the same to me :confused: Played normally from mixer? Sounds the same to me :confused:

I'll do the same tests when the other speaker gets back and go from there. This has got me proper stumped this one :cry:



Maybe it's the louder speaker with the problem?

Hmmmm, doubtful but you never know.

[surround sounds]

I had this problem with my 12inch rcf speakers. One was a lot louder than the other, I taken the speaker to a local dealer and said nothing was wrong. I changed mixers and in the end i had some Professional Van Damme Tour Grade XLR leads made and problem went. If anything they seam louder than ever now.

[Spirits High]

I had this problem with my 12inch rcf speakers. One was a lot louder than the other, I taken the speaker to a local dealer and said nothing was wrong. I changed mixers and in the end i had some Professional Van Damme Tour Grade XLR leads made and problem went. If anything they seam louder than ever now.

I've changed mixer unit totally (MC6000) for a brand new one that was the back up and never used before unit. Currently I'm trawling around for some decent Van Damme / Neutrik leads ;)

[Spirits High]

Well, the speaker arrived back earlier today (Friday) and was given a thorough test out.

On it's own, direct to mixer Ch L, direct to mixer Ch R, daisy chained from the "good" speaker and daisy chained the other way around and super frustratingly sounds exactly the same as the other one :eek:

I've got 2 Weddings over the weekend so it'll get another good runout but totally baffled as to why all is fine now :confused::confused:

[ckpr2]

I had a pair of speakers running off an amplifier and one day the amp blew.

After that one speaker was louder than the other.
I did an impedance check with a multi-meter and one speaker had a lower impedance than the other.
I pulled the faulty speaker apart and part of the voice coil was fried shorting part of it out.

[orbit-dj]

we had a K10 do this at a gig a couple of years ago, one speaker was much louder than the other,

we thought it was the cables, however we didn't try to fix it as it was in the middle of a friends wedding and all the guests were there.

after a hour or so it started to go loud then quite, loud then quite eventually it fixed itself and was fine the rest of the gig, now to this day I don't know if it was the speaker, cables or mixer.

the speaker has never done it again and has been working fine ever since, we haven't changed the cables or the mixer. so even though this post will be no help to you fixing the problem, your not the only person this has happened to.

[super-hero]

Could be a loose connection in the speaker, and the journey to and from Germany has jiggled it about a bit. Or, maybe the ballance settings on your mixer or laptop were a bit off centre.

It's horrible when you can't get to the bottom of a problem, because you never now if it's really fixed.