I'm confused

Lej1447,

Five years ago I set up an HT system using a Marantz 5.1 pre/pro and an ATI AT1505 5x150 watt amp feeding five NHT monitors. I also have an NHT 12" sub and all this is in a 12x14 room. By now all this equipment is yesterday's tech, but I haven't had the urge to upgrade since. It may be because my interest has been focused on 2 channel listening ever since.

But I wll tell you that I never feel a need for more power or dynamics even on demanding movie scenes. It may have to do with what some of the respondents here have recommended about using a high current amp other than the Denon for your front channels. With the monitors set to small and the subwoofer set to cover everything below what the monitors are fed, I get the full effect of crashes, explosions and dinosaur stomps in a convincing and controlled manner.

In my small room, I feel adding more channels isn't necessary.

Lej1447, just some food for thought..... maybe it's not the amp running out of steam, but possibly the wall? I use a Denon 3803 for my HT. It is rated at 105wpc. I am using said amp in conjunction with 89db efficient speakers in a room just slightly larger than your room configuration. Since that room only has 15 amp receptacles, I find that the amp is fully capable of drawing more power than the wall receptacle can provide.

Maybe a regenerative power conditioner may be in order? If you are trying to avoid more amplifiers (space limitations, heat, interconnects, etc.), could this possibly provide you with an alternative? Needless to say, all of your HT components will benefit from a stabilized power source. Power "draw down" or "sags" will become virtually nonexistent. You will find that your amp will sound like it's on steroids, not to mention the clocks in your DVD player and receiver will become much more stable.

You will probably not notice a major difference in SPL by going from 100 to 200 wpc. But, stabilize the AC power and you will notice that extremely dynamic passages will become much more effortless for the amp to reproduce. You would be surprised. That little Denon is probably capable of drawing as much as 1000-1200 watts from the wall at high volume level passages. Unless you stabilize those types of power draws, the amp will have a tendency to sound it's clipping when it is actually not. This also wreaks havoc on your digital section since the DA/AD clocks need a stable voltage supply.

Something like an Exactpower EP-15 or Accuphase will provide you with a very stable 120v/60 cycle power waveform, no matter what type of load you put it up against. Again, ALL of your HT components will benefit from this type of power conditioning, the unit will not occupy a lot of space, will generate virtually no heat, and would probably be extremely cost effective, condsidering your other options.

Also, if you decide to upgrade to other components at a later date, they will all benefit from stable, clean power.

Just a thought.

I didn't post my gear b/c I was afraid such posting would be too long. However, here are my gears and my preference so that I can get more specific help.

* Speakers for main and surround:
Acoustic Research Phantom 8.3 series (quantity = 6)
45-20kHz +/- 3db, 89db sensitive, 50-250 watts
* Center speaker (quantity = 1):
Acoustic Research Phantom 252C with similar spec.
* Subwoofer: Polk PSW350 (150watt)
* Power surge conditioner: Monster Powerbar 2100
* 42" Panasonic plasma w/o tuner or speaker.
* Listening Preference: 50% TV shows, 40% Movies, and
20% Music Videos, ranged from Classical to Hip Hop.

Note: Don't plan to expand from 5.1 to 7.1 for another 5 years. Deal on matching speakers was too good to refuse. Currently, I love to watch & listen music videos through surround sound mode of 5 speakers. Eventually, it will be 7-speaker surround mode.

Questions:

1) The most cost-effective quick-fix method to minimize clip is to get 3-channel amp to drive center & main speakers while the Denon AVR to drive the remaining rear? How about getting a 2channel amp since 50% of my time is to watch regular TV shows in Stereo mode?

2) On one side of the wall, there is 2 electrical outlets w/ only 1 Monster Cable Powerbar 2100 plugged in. Is this considered a dedicated outlet? Is Monster Powerbar sufficient or do I have to get a stage 4 Power conditioner?

3) Any other input regarding suggestion, equipment, and...?

Buscis: While your comments about cleaning up the AC is quite valid in terms of providing a greater dynamic contrast, most multi-channel receivers are built phenomenally cheap. As such, the power supplies sag VERY noticeably when all channels are driven hard. I've seen units that are rated at 100 wpc actually produce 50 - 70 wpc when all channels are driven. Things can get even worse when driving low impedance speakers, since the power supply is REALLY "choking" as each channel tries to pull twice the current as it would at 8 ohms.

As such, going from a "choked" low power level for all channels to a "clean and real" higher power level for the mains and center and allowing the power supply of the receiver to somewhat "coast" and "stabilize" can make a drastic difference. Not only is the end result far punchier and cleaner, the increased stability of the power supply helps with better performance ( imaging, tonal balance, etc... ) in most every aspect.

Other than that, i agree with SD. 12 X 13 is WAY too small for a 7.1 installation. If you are currently running 5.1, what are you doing with the two extra Phantom's that you have ? Sean
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Sean, I agree. HT receivers of this magnitude will always confront you with compromise. Especially in terms of power supplies, which generally do not have the capability of high current flow and the ability to recharge the caps in the power supply adequately in real time.

I was trying to consider the users space limitation factors and also heat concerns being generated by additional amplifiers. My Denon (rated at 105 pc) would probably actually spec out at approx. 65-75 wpc before the THD curve goes through the roof.

An increase of output power from 100 to 200 watts would probably only increase SPLs by approx. 2 db. My point being, the concerns of the user are considering the aforementioned space and heat. Although adequate power supplies would provide a higher dynamic headroom capability, they would also require a higher level current of flow from the wall. It would be kind of a 2 steps forward, one step back scenario.

For instance, if the user were to obtain a quality 3 channel to use in conjunction with the existing Denon HT receiver, he would also need to provide more AC power from the wall. A quality amplifier will increase it's power output based on impedance load. 200 watts @ 8 ohms, 400 watts at 4 ohms, 800 watts @ 2 ohms x 3 channels. That amp, theoretically, would require 2400 watts from the wall.

I was suggesting, instead of introducing those types of power requirements, simply providing a stable, regulated AC power supply that would adjust to current demands, to the existing amplifier. We are both fully aware that the Monster power strip presently being used is acting to "choke" that poor little amp.

I have always firmly believed that problem rectification begins with problem identification. I would be interested in hearing what that system would do with a stable 120 volts @60 cycles without "sags". The user might be pleasantly surprised, and would still be staying within the confines of estblished limitations of room, heat, etc.