dvd deck in rv clipping old speakers?

I recently installed a Pyle PLD52MU DVD unit into my 2005 travel trailer. Installation went pretty well - however, I ran into a couple of issues and am hoping someone can help.  I am currently using the unit with the factory speakers and wiring, no mods to anything as of yet (future upgrades include speakers, speaker wiring, and possibly a sub). 

When I pulled the existing radio out, I noticed the 2 sets of speakers (4 speakers, A+B) were wired in parallel.  I couldn't pull new wiring at the time, so left the speakers in parallel and wired set A to the front wires of the player, and set B to the rear.  Since there was only one pair of leads for each pair of speakers,  I wired the positive lead from the speakers to the positive leads of the front right AND left speaker connections of the  player.  I then did the same with set B to the rears. 

The unit sounds as good as can be expected with the low quality existing wiring and speakers - about the same quality as the old radio.   My problem is that when I turn the unit up past about 4 or 5 (on a scale of 1-20 I believe) the sound cuts out intermittently from all 4 speakers. It doesnt reach any level of distorion, just drops out.  It does the same thing with all sources, although sometimes I can get around it by using MONO with everything but the DVD (was using a 5.1, PCM source DVD).

Is this because I have the speakers wired in parallel?  Because I have them wired to BOTH the right and left?  Or just because of the poor quality wiring and speakers (maybe 15W speakers at best)? 

Also, is it OK to wire the 'Memory Backup' lead to the same positve connection as the Main power supply?  Thats the way I have it now since the old radio only had one hot lead.

Long time reader - first time poster!  Thanks in advance!

throw a meter across the speaker leads and check the impedance...sounds like your putting too much of a load on the head units power supply

sounds like you're bridging the outputs of the Pyle unit which you cannot do.  You will be only using two speaker outputs from the Pyle HU.  Pick front OR rear and then connect left and right speakers.  You will have two sets of speaker outputs from the Pyle HU that will not be in use.

I'm not trying to disrespect you in anyway but "imaging" and "Pyle" are definitely two words that should never NEVER be used in the same context. lol.  Your factory wiring will be more than suitable for your system.  Add an amp and you would still be ok.

Ha - no offense taken.  Im new to the car audio world (long time audiophile of home gear..) and frankly, I went cheap because, again, this is a camper install.  I guess 'imaging' was the wrong choice of words - what I should've said was 'channel separation'.

thanks for the info!