Question AV receiver speaker configuration advice

I have an Anthem MRX700 receiver, Focal floor standing for front speakers, centre and sub as well from Focal. Reused some old panasonic home theatre speakers for rear. The setup is in use for couple of years but the receiver has failed couple of times with "Amp protection powering off" message every time when I tried to watch a movie with good surround effects. I had to take it to the supplier and it was repaired as long as it was under warranty. Now it failed again and they blame the speakers for over driving the Amp and ask me to pay for fixing it. I have checked all the obvious aspects like wiring for short circuits etc. I have a doubt if my rear speakers are not matching with the specs of the Amp or front and thought would upgrade them with some second hand KEF speakers. Before proceeding further, I would like to know if I'm doing anything wrong in my setup, what aspects I need to check (eg: Impedance, type of connectors for cable?) and if there are any options for me to prevent a faulty external source from affecting the Amp. Any suggestions would be really helpful.
 

Rambles

Distinguished Member
Adding a power amp for the most demanding speakers would be a good step to try.

If budget is tight try some pro audio amps such as the Behringer A500 or A800 or the Crown XLS1002 or XLS1502. Or, a secondhand consumer power amp. If money isn't tight, then get a nice multi channel consumer power amp to drive all of the speakers and just use the Anthem as a processor.
 
Thank you for your reply. The front channels are now fed through the focal active sub woofer (crossed over at 80Hz). Should I still worry about the front or just add the power amp only for the rear speakers?

Listing down some specs if that would help in providing some suggestions.

The Anthem has a rating of 120W 8Ω for front channels and 90W 8Ω for other 5 channels.
The Focal front speakers can serve up to 250W and centre speakers 200W both at 8Ω
The KEF KTH2001 satellites I'm planning to replace the current Panasonic for rear and side channels have a rating of 10-100W and 8Ω.
 

Rambles

Distinguished Member
The front channels are now fed through the focal active sub woofer (crossed over at 80Hz)
I don't think that can be right, unless something very unusual that I have never heard of is going on o_O

Are the front left and right speakers connected to the speaker output terminals on the Anthem? Which model of Focal speakers are you using for your front three speakers? It is possible that they are rated at 8 ohms, but have impedance dips that take them down to 4 ohms or lower, this can push some power amps into protection mode. Also, are you using the ARC room correction? If you have any big nulls that you are attempting to boost, this also can put big demands on the power amps that can cause them to fail.

And of course, volume, if you have a large room and / or like to listen at high volumes, that could push the amps over their capacity.

Troubleshooting would be to switch off ARC, if you are using it, and see if you still get shutdowns.

If so, and you want to be cautious, pick up a very inexpensive power amp, can you get the Behringer A500 or A800 in New Zealand, from a store with a good returns policy? Try that on your front left and right speakers, or get two and try using them on your front three speakers.

There is always the possibility that the Anthem is faulty, but it does sound like a problem that could be fixed by adding external power amps to the front three speakers. No guarantees though.
 

Leelo

Active Member
Like Rambles said I’m confused as to how you are connecting the front speakers via the sub. Ideally for movies and or a mix of music and movies you should be connecting the front speakers to the Anthem directly and have the sub connecting to the anthem via the sub rca pre out. I suspect that either you may be just exhausting the Anthems capabilities in which case I’d agree with Rambles and look to power the front 2 or 3 speakers with a separate Power Amp or amps it’s also possible that one of your speakers has an intermittent fault that’s causing the Anthem to go into protection mode but that’s unusual. Are you able to check the integrity of all the cables just in case they have any potential to short etc. I don’t know about Anthem kit but if a Yamaha amp goes into protection mode it doesn’t require a repair to reset it you should be able to do that yourself are you sure that they are actually repairing or replacing parts when you return it. One other question how well ventilated is the amp it’s possible that when you are driving it hard it may be overheating
 

gibbsy

Moderator
Those Panasonic speakers may be very low, I've seen some 'all-in-one' speakers being as low as 3.2 ohm and certainly should not be used as it can lead to the type of problems you have described. If this is a big part of the problem the KEFs should sort that.

Your wiring though is causing a few questions to be asked as in a normal 5.1 with all the speakers connected to the receiver it should have no problems driving them. Ventilation will play a large part in heat build up though.
 
Thanks Rambles, Leelo and Gibbsy for your time in replying to my question. I will try to answer your queries here. excuse me for a long reply and please ignore that parts that look irrelevant.

I think I didn't explain my setup clearly. I have Focal Chorus 726 for front speakers and Focal Sub 300P. The sub can be configured (I guess like most other subs) in 3 different ways -
1. High level input from Amp and front speaker output from Sub
2. Low level input from Amp
3. LFE input from Amp

With high level input (as per the sub's manual), the front speaker (R&L) output from the receiver are connected to the high level input (R&L) of the sub. The speaker output from the sub will be connected to the right and left front speakers. In this case, the Amp will have sub/LFE turned off and will be sending the full frequency spectrum for front channels to the sub. The sub will have 80Hz crossover setting and so will send everything above 80 to the front speakers.

Please refer to page 17/18 in the manual to see what I'm referring to
https://www.focal.com/sites/www.foc...talog/document/sub300p-user_manual-notice.pdf

earlier I have also tried the LFE input to sub and front channels connected directly to the Amp (crossover set to 80Hz in Amp for front channels) but found the high level input setup more enjoyable especially while listing stereo music. Either way the Amp has failed in both setups at different occasions and so this may not be a point of interest for the fault? But I most welcome your suggestion on an optimal setup.

I'm not using ARC and I just adjust channel volume levels based on the movie content since they are not the same for different movie sources.

To give some timeline, the Amp and speakers were bought about 3 years ago. The Amp was an ex-demo model I bought for a discounted price and it first failed in about 3 months. The dealer fixed it for me and it failed again in another 2-3 months. I asked the dealer at that time if it was anything to do with the speakers/wiring I'm using and he told me that even if it was the case, it shouldn't fry the board and the Amp should be able to protect itself. He spoke to the distributor and arranged me a replacement Amp. This went on well for good 2 years and failed in December last year. In the meantime, the dealership was bought by another company and they are not accepting it as part of warranty and do not believe that its a fault with the Amp. Like Leelo says with Yamaha, I too was expecting that the protection mechanism must be something that we can reset ourself rather than spending for repair. I tried to raise a case with Anthem directly through their website asking why such an expensive Amp would fry its components and if they can provide any firmware update but they just said that its an external fault and they can't do much about it.

All the 3 times when it failed, the issue occurred while I was watching an action sequence in a movie and so the sound level was going up and down across the channels. I listen to music like 2-3 hours a day with the front channels and in fact with much louder volume than movies but never had an issue. When it failed last time, the unit was extremely hot and I left it to cool down overnight. In the morning, it was powering on and I was able to listen to music for a good couple of hours. Later in the evening, I tried to continue the movie again and it failed at the exact scene and never recovered:-(

The Amp has gone for paid repair and I will upload the repair report to see if you can find any clue there. I will receive it sometime next week and in the meantime will try to check the wirings, add a cooling fan and replace the rear speakers with KEF. Then I can try to play the same action sequence again and if it goes into protection mode again (which should hopefully not fry the board), I will go for adding the power amp or just decide to use the setup for listening to music and buy a Yamaha for watching movies :)

Thank you very much guys for your patience and time.
 

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Rambles

Distinguished Member
The extra info helps a lot for it all to make much more sense. It sounds like you are on the right path, good luck :smashin:
 
Hello Everyone.

I thought I will give an update to my situation and ask some questions . So, after my anthem was repaired, I added an AC infinity component cooling fan, rewired all the speaker cables and changed the rear speakers to KEF as mentioned above. I was primarily listening to music occasionally some movies without any issues (Didn't have the courage to play the sam movie again to see if it breaks the anthem again)
I now have a 7.1 setup with the KEFs as rear and side speakers. I somehow felt that the 7.1 setup was not properly working and so thought I will do some testing. I downloaded some 7.1 test files and trailers from dolby website. I used Kodi on Nvidia shield to play the files. I noticed that when I play the files with passthrough enabled there was considerable amount of distortion (clipping) across most speakers even on an average volume for movie trailers. If I have passthrough disabled on Kodi, I see minor distortion on the rear/side speakers but the front were ok. Does this mean my Anthem is not capable of driving the Focal (front) and KEF (rear/side) speakers? Do you have any suggestions for additional testing? In order to address the issue, should I consider buying a better receiver or add power amp to the channels? Any suggestions on models?

Thanks in advance.
 

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