Diffuse Front Wall? Absorb rear wall?

I'll research existing threads, but quick basic question --- is it a basic tenet that I should use a diffusing approach for the front wall and an absorption for the rear wall behind my listening position? I bought a wall rug, put it on the front wall, and though it seemed to quiet the room down in some good ways, it seems to have sucked some of the energy and sparkle from the soundstage. thanks.
I thought SOP was the opposite. Of course, it will always be room dependent.
It depends on what kind of speaker you have. For dipole or bipole, I would do what you suggest. For others, I would do the opposite.
Diffuse the rear, absorb the front, as a general rule. Windows should always be absorbed.
LEDE rooms are the other way around. Even in relation with room acoustics, most folks here will opine that anything goes so long as you enjoy the sound and are "emotionally involved".

LEDE rooms are a bit passé as computer programs are now used to make a finer analysis of each room.
The front is a matter of taste but a live front end is often more pleasant sounding or lively. Generally it is best to absorb on the rear wall behind the listener...if you sit with your head near this wall then you need diffusion behind you for sure.( normally you should sit 38% of room length and at least 3 or 4 feet from a wall.... 8 feet or more is much better)
LEDE was out of the recording industry in the 60s. It was for control rooms, not listening rooms. Go to this page. Click on the article "on the soundstage" by Chris Huston on the right hand side. This will give some insight into the differences of a control room and listening room. For those that don't know, Chris Huston has over 40 years experience as a recording engineer, producer, studio and media room designer. He has over 80 gold and platinum records to his credit. He is an amazing source of information--and a great person too.
Thank you for the input to all. Variety of opinions and experiences. Subjective hobby. Appreciate the insights. For what it's worth, the last couple nights I've been listening with the rug behind me (apprx 3 ft behind me in a 22ft room -- speakers are appx 8 ft off of the front wall --- and I now have a row of ASC Sound Panels and one Tube Trap in the middle across the front wall). Pretty pleased with the sound. Think I need some basic absorption stuff on side walls now, and may be close. Thanks again.
FWIW, you will almost certainly benefit from moving your listening position another 2 two or three feet from the rear wall. (towards the speakers)

Also if you place more broadband absorbers behind you (closer to the listening position) then it will help you achieve a larger sweetspot and much better articulation in the mid range. Tube traps are narrow band absorbers - so placement is very tricky - unless these are just absorption columns (not the same as tubes)

I would go with treating at least three corners with big broadband absorbers like GIK Tri-traps - 16 to 20 linear feet of these big guys should start to make a difference. Corners roughly double the effectiveness of trapping.

Why big broadband...because this is easy and works down to about 100 Hz even may have a little benefit at 50 Hz. You can almost never get enough of lower frequency absorption - although you can over do it with mid and trable panels.

I find the GIK's tritraps are just big enough that a single 4 foot tall panel will impact sound in a corner very obvioulsy and audibly at a distance of up to roughly three or four feet away. Further than this and the effect is more subtle and you need to add much more than one panel to get a significant improvement at a listening position that is six feet away or more.

I have four or these large panels and it makes a noticeable improvement...I should do more but there is a limit to what I can accept aesthetically.

Alternatively, I built a huge firelace with stacked logs directly behind the listening position which acts as a random RPG skyline type diffuser and a broadband absorber to boot; an extremely effective and stealthy way to cut down on rear wall reflections. This is similar to your idea of hanging a heavy rug on the rear wall which is also a clever idea. BTW - if you can get your rug an inch or two off the wall then it will be even more effective at absorption.
I previously had 4 pieces of RPG omnifussors at the rear wall. Shifted them to the front wall and placed CD racks at the rear wall. In other words, I had diffusion at both front and rear walls. I find this configuration to be better than having diffusion at front and absorption at the back behind the listening position. The sound is spread out more uniformly without losing energy especially in the high frequencies. I already have absorption at both side walls. Too much absorption kills the high frequencies, dynamics and soundstage. Used moderately will yield excellent results.
I replaced the Sonex foam I had with 3 diffusers (each 2' x 4') which I put next to one another along the front wall behind the speakers. My speakers are about 5' out from the front wall. The diffusers increase ambiance and I enjoy the change. It also increases strident sounds. I discovered that Cabledyne power cords cut down a lot of the strident sounds. ASC tube traps also help.
May I ask what fq. range diffuser do you use behind speakers? Currently I have 1 mounted behind each 34 1/2" tall speaker. Diffuser panels are 2x4’ raised 1’ above floor. This design is tested effective in the neighborhood of 3100 hz on up. Does this sound ok (no pun intended)? I'm a little limited with placement being that theres a wall mounted LCD 3' above floor level. 
ASC makes a model called the Martix Panel, designed for the wall behind the listening position, if the listener's head is within two feet of that wall. It provides a mix of absorption and diffusion, so as to not make for too dead a sound. Maggie owners use tall Ficus trees behind their speakers as diffusors, and then there are LP racks which are of some benefit at scattering sound.
Basic answer-yes. Maximum diffusion (phase+time) behind the speakers will allow you to best hear what your speakers produce. I like a combination of diffusion and absorption on the rear wall.
After speaking with one of the well known manufacturers of acoustical products, based on their recommendation, for my new room I will be treating the front corners and first and second side reflections with absorption/traps; and the back wall with a few of their absorption/diffusion combo products. I will then evaluate further to decide if i need anything else. 
@meerzistar. I ordered mine from ATS on Amazon. Each diffuser is about 8" deep and scatters from 325 Hz up to 3000. In the past few days, I've added more ASC tube traps and they really clean up the strident sounds. What really helped was a pair of 16" diameter traps 4' tall, one in each front corner (w/smaller diameter traps perched on top so the whole column goes up to the ceiling. Then, more tube traps on the first order reflection points against the side walls. So, now I have the best of both worlds, ambiance and timbre. Here's were you can find more info about the diffusers. http://www.atsacoustics.com/acoustic-diffusers.html
I have been experimenting with different DIY diffusers. Having a workshop at my disposal and endless lumber scrap supply if I'm not happy with a design I move onto another. I'm currently in the process of a 2x4' cherry/mahogany/maple/oak horizontal placed diffuser with the boards running upright. Depths range 1 1/2"H with 1/2"D being the shallowest glued and nailed to birch ply. After extensive prepping I'll be applying Watco Danish oil to further raise WAF. I intend to place this between 35" floor monitors front and centre a foot lower than a large LCD and 1' above floor. I'm optimistic.  I also plan on some 6" deep light maple diffusers similar to the ones ATS sells  
Rockadanny please remember manufacturers talk to the public(i e customers) with a view to sales;wouldn't you agree? Pete
ptss - thank you for the good advice. yes, one does need to keep their bs radar on full scan whenever speaking with a manufacturer, dealer, or fan boy. that is for sure. GIK Acoustics and Brian Pape have helped me resolve some past issues so I am fairly confident in their assistance this go around. But still, I do proceed with caution.