Amp is going into short circuit mode

Hello,

I need some help with trouble shooting my system set up.  The problem that I have is with my Clarion APX4360 amp which keeps going into a short circuit protection.  The amp is rated at 4 x 90W at 4ohms, and I am running 4 focal polyglass components which are rated at 75W nominal, 90W max and these are 4 ohms components.  The volume on the HU goes from 0 up to 33.

Here is where it gets interesting:

When I play songs that are recorded well, ie clear, good dynamic range, no background noise the amp short circuits at a volume of 26,  when I play a song that is not recorded as well and it shorts at around volume of 29 and sometimes around 31.   In either case it seem to short itself when there is distortion starting to enter the speakers.   Once I put volume down for it starts to work again within few seconds.   I know that the Amp is not overheating, because it is not even warm to touch, and also it has a build in diagnostics and it show as short circut when it shuts down.  Overall the system does get lound, however I can sit in the car and listen at full volume without any problems, a bit disapointed becase I was told the the focal speakers get very loud and that I would not be able to sit in the car.

I just want to figure out why does this amp shor circuits?

Is it possible that the amp can sense the distortion in the speakers and shut down?  I have never heard of such feature on an amp.

Is it possible that the speakers itself have some sort of a distortion protection and create a short circuit to shut the amp off?  I have never heared of such a feature in speakers as well.  I know these are good speakers but still...

Is my amp simply not good enough for the speakers?

Any suggestions, or advice please let me know.

This is simple....

take the speaker wires off the amp and meter each pair one at a time and VERIFY that each set is 4ohm +/- a few tenths. If any are measuring low there is a problem with that speaker or the terminals/wires.

If all meters good check for a possible shorted speaker wire by setting the meter to continuity or resistance and place the negative probe to ground and probe every speaker lead one at a time with the other probe.  If you get ANY reading from chassis ground to a speaker wire...you found the culprit...repair as needed.

If you do not have a meter or know how to use one you can do it the "ghetto" way and just hook up one speaker at a time to the amp...the speaker that causes the cutout is the culprit.

If all checks out well with ohms and no shorts..you have a bad amp.

Do this and post back so I can say..."I told you so"  lol

"4-ohm" speakers will almost always have DCR less than 4-ohms since speakers ar rated at their nominal impedance, not at their resistance.  Unless they are open or completely shorted reading their DCR may or may not tell you anything useful.

If the amplifier gain is set correctly speakers can short out at higher volumes for a couple of reasons, including over excursion (try adding a high-pass filter to them at around 100Hz) or in some designs the tinsel leads can slap against the speaker frame and momentarily short the amp to ground.  I have also seen stray strands of the speaker wire touch or almost touch ground and this causes amps to shut down at higher volume.

I was refering to the DCR..and I mentioned +/- a few tenths because the DCR is usually around 3.7 ohms.But if it reads 4.2ohms..I would still see no harm. When using a meter to find out why the amp is going into protect mode..I look for low dc readings...like 1.3ohms as an example..well basically I see this all the time..a defect or damage in the voice coil which allows the amp to play up until a certain level..then cut off..If I didn't see this ALL the time..I wouldn't have reccomended it be tested this way. I also look for shorts..I also see amps that can play through a short at moderate volume..weather it be a wire pinched..or voice coil tinsels touching..or a speaker that is internally shorted to the frame (it plays fine when you dismount it)..well you know..the basic things you check when an amp cuts out..

But after reading this post again....I might have to agree that it could be happening due to the gains being too high..it is hard to pinpoint a problem like this without actually hearing at what level this "distortion" as described is coming in. But worth a check regardless.