Axiom Home Page Forums General Discussion Advice from Axiom Owners Help! I think I need more power.

I see no economic advantage at all by going with separates over new AVRs. The problem is that they usually charge as much or more for the preamp-processor than they do for a receiver with similar features simply because separates are seen as higher-end. The main reasons I went with a pre-pro over a receiver is because the Integra DTC-9.8 seemed like the way to go at the specific time I was buying, since I don't remember any standout receivers that could decode the new sound formats. If the Denon 3808 had been out, I may have gone with that, but at least this way I got to have cool XLR connections. I have to say I like connections that click into place instead of connections that you slip (or force, red-faced) on.

There's a newer Integra out, but I haven't really read up on it. I'm still hoping the new Outlaw's Trinnov EQ is compelling enough to upgrade to. Other than that, I don't know what pre-pros are out there. I'm sure there are more options as you're willing to spend more thousands of dollars.

Dean, I'm not sure what "between all its channels" means. You don't add up the power each individual speaker uses to determine what the amplifier rating should be. For example, if five speakers were using 100 watts each(doesn't happen simultaneously in home use), a 100 watt, not 500 watt amplifier would be needed. The usual 2-channels driven at max for 5 continuous minutes rating, as required by the FTC regulations, is fine for real world application where all the channels aren't simultaneously driven at full power.

My general view is that unless more maximum power than the receivers with ratings in the 100-150 watt area can output is actually needed, the cost effective buy is the receiver. The economies of scale involved with receivers as compared with separate components practically amounts to paying the same or less than what a separate pre-pro with similar features(if available at all)would cost and getting the amplifier for free. If more maximum power was actually needed, a professional amplifier rated for at least 500 watts(less doesn't make that much difference)should be considered as a relatively inexpensive alternative.

@ Charles - I was considering the new Outlaw 997 which is another reason I was eyeing separates.

@ John - The example of the “Master and Commander” opening battle scene is about the best way I can describe what I mean when I say “all channels.” In my apartment when I set the volume so that the average SPL was about 80dB everything sounded very clear and precise albeit loud during the opening battle. Here in the house (larger room + 2 more QS8s) when I set the volume for and average of 80dB the opening battle is painful when explosions rock the ship, splinters fly and all the speakers seem to be pumping out lots of sound.

My assumption was that the 2807 had enough power to handle the 5.1 duties in the smaller room but is distorting/clipping with 7.1 here in the larger room. Is this a valid assumption or is there perhaps something else wrong with the 2807?

Assuming it is underpowered at “110 watts/channel” (Denons claim) how can I figure out how a “so many watts/channel” claim translates to being able to drive all 7 speakers in a demanding scene like the “Master and Commander‘s” opening battle.

Dean, I'm not familiar with Master and Commander(my music/movie ratio would be something like 99 to 1), so specifying that particular scene doesn't really clarify the problem for me. It's said that even seemingly very wild scenes very rarely have all the channels going near full-blast at the same time. Be that as it may, one of the receivers that actually does base its rating on an "all channels driven" measurement(e.g. HK, NAD)can be counted on to actually deliver the rated power to all seven channels simultaneously for at least five continuous minutes, because that's the test it had to pass to comply with the FTC regs.

Even some receivers that use the more typical 2-channels driven rating come rather close to that number even on an all channel basis when tested by labs such as Sound&Vision or Home Theater Magazine. Denon is one of those that usually does come close, so besides being able to count on the 110 watt rating being met, all channels might be something on the order of 90 watts.

Dean. A pro amp is what the musicians use. Crown is one example, Behringer another. The Behringer EP2500 puts out 800w/channel at a cost of around $350 new. Now, a lot of audio guys don't think the 2500 is clean enough for powering mains, but even if you go with more reputable pro amp suppliers at double the cost, it is still a lot cheaper than consumer grade separate amps.

There are some good discussions on avsforum about pro amps. The biggest downside is that some of these amps can have noisy fans cooling them that need to be moded for home use.

John. Thanks for the additional info on Toole. I've wondered if anyone did any measurements to verify how sound falls off in an enclosed space.

@ John - Thanks for the explanation and examples of manufactures. Just to be sure I’m understanding…something like the Denon 3310 rated at 120 watts/channel x 7 should be able to drive my 7 speakers to the parameters already discussed without distorting in even very demanding scenes?

@ Fred - Thanks for the advice. I’ll check out AVS hopefully those sub-forums aren’t as bad as the speakers ones. Noise should not be an issue as all my equipment is located in the office adjacent to my living room behind a set of French doors. I use to always be able to hear my computers and especially the Xbox running. Now nothing but silence from my equipment and its on an open rack so getting to anything is a breeze.

@ anyone - is there any disadvantage to having a long wire run from a pre-processor/receiver analogue outs to the amp. Reason I’m asking is that if I did get something like the Emotiva XPA-3 to power the M80s I could place it behind the screen which would also put it on a separate circuit from all the rest of the equipment in the office.

Part of the reason I ask is because sometimes on my weekdays off I can hear very faint music coming from my center M22 speaker when my system is on and nothing is playing. So I wasn’t sure what was causing it to pick up a stray signal or were it’s coming from . It’s inaudible when anything is playing so I haven’t tried to figure out why it’s happening or why only that speaker (only thing different about it is that it’s hooked up via a switch with the M80 center).

Not necessarily, Dean. Keep in mind that when a receiver spec says something like 7x120 watts, that doesn't mean that the rating was with all seven simultaneously driven at full power. If language such as "all channels driven" isn't used, it's to be understood that the rating was with two channels driven. But as I said above, Denon and some others have tested out with all channels fairly close to the two channel rating. Again, my view is that all channels simultaneously at full power rarely happens outside test labs, but someone with a different view should consider buying a receiver rated with all channels driven or should buy only units that have published lab tests showing high all channel numbers. For example, a very inexpensive receiver that I've owned for some time was rated at 75 watts with two channels driven, but tested well above that number and at 71 watts even with all seven channels driven. Plenty of power with even my most dynamic classical recordings.

The pre-outs are pretty low level which means strong outside interference will have more of an effect on them, than say the speaker level lines. Good quality, shielded coax will help a lot. Shielded XLR will help even more (provided the preamp and amp both have XLR jacks).


Sounds like an AM radio station is being rectified in some piece of gear. Get an AM radio and scan the dial to see if you can find the same music playing there. Not that it will help anything, just confirm the theory. Could be the switch, or even the power cord of the receiver--don't know why it would be only one channel, but stranger things have happened.

Dean, is the music you're hearing coming from the tuner?

Keep in mind that if you plug your external amp into an outlet on a different circuit, you might end up with some ground loop hum.