How to unleash the optimum power of a receiver?

I've got a Denon AVR-2805 hooked up with Jamo speakers and two Definitive speakers.

So far they sound great. I was just wondering how I make the optimum set up and unleash and get the most out of their capabilities?
Fiddle about with speaker placement, that will result in the best, and cheapest way to improve the sound of your system. Generally, if you can get the speakers away from the back and side walls at least 2-3 feet, this will help in damping early reflections, allowing for a deeper, broader soundtage and more pinpoint accuracy in the placement of the instruments and vocalists.

Speaker location and some room treatment could provide a great deal of improvement. One common mistake is the position of the three front speakers. Many people pay no attention to the plane of these three speakers which can throw their timing way off. Another glaring issue is that most instruction manuals show the front left and right speakers drastically toed in and this may the case with some situations. With room correction off or flat, try centering the speakers baffles on the same plane then slowly toeing in the front right and left speakers in equally. You should notice a sense of the dialog becoming more or less spaced apart. The goal is to get the illusion that the dialogue is coming though the screen yet still maintaining location.

This repositioning of the fronts may require an adjustment of the two side speakers. Beginning at just a foot or two in front of the listening position and moving them back slowly to just behind the listening position until you find their optimum location. This location can be trickier than you might think. I've experienced some films were their location seemed better just behind and others directly across form the listening position. The side speaker location is very subjective. After these location adjustments run room correction again.

Limiting your speakers low frequency and using a subwoofer can make a huge improvement. I would guess most receivers would benefit from matching speakers that stay above 4 ohms and have high sensitivity ratings.

I think the 2805 is a 7.1 receiver without the latest codecs? These will become more important as the media ramps up their production methods. There will always be a newer better component out there. For now it seems the hardware is one giant step ahead of media production. If your happy with what you have already then no worries.
if your receiver has preouts, which i think it does, you can add a two or three channel power amp for your fronts/center--typically, this will sound much more powerful and cleaner than using the internal amps in your receiver, which are wimpy with all channels driven.
"So far they sound great".

So what's the problem? Give the forum more information and you'll get more specific answers.
Thank you all for the generous answers. And thanks brewed for the question.

I was just wondering how I would know if my receiver had performed its best. Is there any specific measure that could tell me if the receiver has reached its optimum power?

Also, I had to pump the master volume to around -25dB to -20dB to get to level that I can enjoy. What is the max volume a Denon AVR-2805 could go?

Thanks, again.
if it's still using the stock power cord, i would think that the easiest improvement would probably be to stick a better power cord on it (if its power cord is removable).

you can't beat "my audio cables" here on audiogon for price-to-performance ratio, or a ps audio cable that's shielded like a mutha****** or anything like that. best $50+ you could spend on it, i would think.

feeding that thing all the power it wants will help its sound.
audio video receivers are, ultimately, going to yield you limited power distribution, as compared to better separates based systems, everything considered. Not knowing your speaker models - unless your main speakers offer at least powered woofers - my first thoughts are you will get advantage in running whatever speakers you have at 80hz on your receiver (even if they're full range), and letting a powered sub do the bass. Dynamics will most always improve greatly, and the system will be much more efficient, less taxing on the receiver to be certain. Yes, you must ALWAYS anyway consider making sure ea speaker is placed properly, and the system set up well as a whole.
So, yes, I'd focus on making sure the system is set up to maximize the sound, so do your research here.
Also, adding an outboard amp will greatly help your situation.
BTW, does your receiver have audyssey? If not, the newer will do better for your acoustics in helping smooth things out (remember to not place speakers in acosutic "holes" to begin with, as you can't fix that with an EQ). It's a thought. Staying with things as is, it's settings, speaker/seating placement and acoustics, basically. Adding better amplification yields an easy 100% improvement in soujnd, most always, as well! However, to be true, running your speaker as small does make for a much improved sound on it's own, as opposed to running full range.
What model speakers again???
Another thing is to amek sure you have matching speakers up front, at the very least, and then ideall matching all around if you can.
Btarianto, I believe the -25/-20 dial on the master volume that you refer to really does not mean much about the quality of the sound. If this is your concern, the best thing to do is to get a RadioShack SPl meter to set your SPL level at optimum and to balance the sound level of your speakers. In a 14x16 room, when I using the MACC on my Pio SC05, my FR/C/FL was calculated at -5db ( in range with the level of 75db/ C weight on the SPL meter) and the result is I have to dial up the master volume to 25/20 but in a whole, the sound quality is much more balance. Interesting enough, some of the salesman at local store boosts all the speakers to 0db manually and as the result, the master volume does not have to crank up higher to give customers a sense of false "powerful amp". I asked one Bose rep why did he do so, he simply replied :" it sounds better". Not, louder is not better. Quantilty vs. Quality. Go figure.
I am listenning to my budget Pio A35r intergrated right at this moment. At 45WPC, at the same set up ( speakers, source, cables...), the Pio A35r intergrated at between 10 and 11 o'clock position sound much louder and more musical than my 130 WPC Ice power at -25 dial on the master volume. A $200.00 intergrated vs. $1,800.00 AVR in 2 channel audio playback ....Just a thought about your concern with your master volune level so I take note.
Placement within your reason/available space, balance all channels to same db level, and if using a sub...use a good one (svs, hsu, velo, ED, JL). Some damping in room (sofa, drapes, pillows) as well as some reflection from walls/ceiling. I do believe you can replace pwr cable (signal here at the gon). If recv'r is calibrated to reference your vol indicator lets you see at a glance approx level compared to reference level of about 105db. This is based on Dolby/DTS reference level for movies. Remember, it takes a doubling of output pwr to increase 3db...thus at a -24 level you are wwaaaaayyyyyyy far from amps capability when it is going to take twice the given pwr to go from -24 to it? Your 2805 tops out about +16 or so...perhaps +18/+20. Friend has a **02 series and my son has a 1602 in his ht rig I put together for him. Theirs go to +18. Anything past 00 would hurt you or small creatures in the vicinity if setup properly. Use the auto setup feature for spkr distance and level calibration if you have the mic that come with it. Otherwise as advised, use test tone and adjust ch trim so that all are same on spl meter reading 75 db with master gain set at -10 or 85db with master gain set at 00 which most people find much to loud/annoying. I advise -10 on master volume knob and adjust until the test tone reads at 75db on spl meter so you don't damage your spkr drivers.
I really don't think you need to look at your receiver to improve the sound... if I understand your post correctly, you are using mismatched speakers (Jamo w/ a couple of Definitive Tech's); this quite often leads to mismatch as the sound pans around you. I would replace the DefTechs (although DefTech does make some great products!) with a pair of matching Jamo's to keep the sound coherent.