Axiom Home Page Forums General Discussion Home Theater Ditching front QS8's

The DSP in the EP800 will also add to the sub's distance setting. Mine show up as 28 feet or so away despite being only maybe 8-10' away.

Something does sound funky with the disparities you are describing so it is really tough to know for sure what's happening but it sounds like it's getting figured out and rectified.

Just thought I'd take a stab at question #1 How can you blow a speaker that is 400 watts with just a 125 watt amp?

A good question and many years ago, I thought exactly like you. Basic Math right? However, I'll take a stab at how the opposite can be true in layman's terms.

I don't know how loud you were trying to reach or what issue was creating the need to drive certain speakers louder than others but in regards to question #1, if you keep requesting more volume , essentially the speakers will attempt to suck more and more power from your amp. Because the speakers are rated higher than your amp, you eventually reach a point where more wattage is needed than the amp can actually dish out. The speakers are not maxxed out, but your amp is.

The amp, will try it's best to a certain point. However eventually it can no longer produce a perfect sign wave of signal. The lows and the highs get cut off. If you were to run the signal through an oscilloscope, it would look something like this.


Speakers HATE signals like this as they are supposed to vibrate smoothly in relation to the signal wave. This effect called is "Clipping" and it can and will damage speakers, at the very least it creates distortion. Often amps have protection circuits built in to shut things down before it gets too severe but it does commonly happen to a point if you drive to much volume.

Short answer:

A big wattage amp can indeed blow low wattage speakers
but
an underpowered amp can also damage even high wattage speakers because it can't handle the job.

Am I saying you need a bigger amp? No. Not unless you enjoy ear damaging volumes or your room is huge. 125 watts is fine for most people. Essentially, if you are playing with the volume button and the sound starts to sound distorted or simply worse instead of better, you have driven your amp into clipping. If you hear clipping but you still want to go louder, then yes you definitely need a bigger amp...... and probably a hearing aid down the road (room size aside).

I have no idea what was the 100% cause and effect of your issues but I thought this bit of trivia would be handy to know in any case.

Thanks Murph. I knew that someone could explain it better than I could.

Ditto Murph...picture and all.
I have a denon AVR-3311CI and it confuses me the relationship between "channel levels" and master volume. If I set everything manually to zero dB the front L/R speakers overpower the center and surrounds. So I would think I should increase the center and surrounds by maybe 3 dB to compensate. Now forget the surrounds and lets talk about the center.

When I increase the dB for the center using audio adjust "the staic sounding test" I get close the the fronts and think all is well with my level adjust. It seems 2-3 dB is enuf to make the center sound even in volume to the fronts but when I play a movie the center sounds muted and lacks bass compaired to the fronts by a large amount. I try to increase the center even more but still I get the same effect, more volume but muted and lacks bass, like the woffers don't work right. So it's like the center level adjust doesn't work in an actual movie.

The only thing that makes the center sound full like the fronts is using the "matrix" mode and I think all that does is mix the sterio from the fronts into the center, not true 5.1. I have no clue but it's the only way I have found to get the center even in tone and volume to the fronts.

Shouldn't I just be able to start a movie and the denon select the surround mode so that the center is separate from the fronts or am I confused about "matrix" mode? I try direct and pure modes but the center then goes back to sounding muted with little bass. What is matrix mode anyway and why is it the only thing on my reciever that makes the center sound full like the fronts?

I have played with all the manual input modes like dts and dolby but none give me the full center tone like matrix mode. Is this normal?

If your watching movies, the display should say something like Dolby Digital for example, or DTS if your in that mode for Movies. Sometimes you might see PLIIx during the DVD menu previews prior to the movie. Direct and Pure modes I believe are more for music listening and disregard your bass management modes for movies.

The Center channel is more for dialog in movies and surrounds for surround affects. I'm still a bit confused what you could have been cranking up to blow the Q's.

It doesn't matter if you set the levels for each speaker to 0dB or even -10dB to start, as soon as you run Audyssey they all get reset and changed based on the test results. If your doing it manually, normally people get an SPL meter and match all the speakers to the same pink noise around 75dB or so...

Drifter, I'll try some of your questions.

2. and 3. No, a separate amplifier with a higher maximum power rating doesn't help the sound unless the speakers are playing so loud that the higher power capacity actually is used. Your 3311 should have plenty of power for your needs. The A1400-8 has been unavailable for some time and it's uncertain when or if it will be.

4. The major differences in how the center speaker and left surround were set would seem to indicate that those speakers were either defective or damaged so that they had to be set much higher to match the loudness of the other speakers. No, calibrating manually with an SPL meter doesn't give more accurate results than the Audyssey(or any other)auto calibration system. It adds human error in reading the meter, and, if anything, is less accurate.

Yup. Head nods everywhere.

Common consensus is that if you have Audyssey and a proper mike that came with it, at least use it to calibrate your speakers to equal levels. This will give you the best results to re-create the spacial audio effects as they were intended by the creator's of the film/music. There is a second phase where it corrects for your unique room characteristics across all the various frequencies, but that is another discussion.

In the absence of a receiver with an automated system, use an SPL meter to get them all as equal as possible.

After calibrating the levels to be equal, many people do in fact tweak the numbers just slightly. Especially the center channel. It's very common, to turn up the center channel a db or two in order to get more clarity in dialog, a track that often seems mixed a bit light in movies. If you have ever held on to the remote to play constantly play with the volume controls between dialog and action scenes, you know what I mean. This will rectify that problem without throwing the spacial effects off too much.

Finally, while Johnk is correct, Audyssey probably does do a much better job at calibration vs. the SPL meter, I simply can't resist my inner geek to break it out once and a while. Sorry John, but I do love gadgets, even when my brain tells me I don't need them.

Thanks agin, this post is morphing into other subjects now so I think it's time to kill it.

I usually bump the sub up some too.

Do want auto-calibrating receiver... not a great time to upgrade right now, though.

SPL just focuses on volume and not trying to correct room issues, but many people swear by it. Do some sort of regulated calibration (either built in to the receiver or get an SPL meter) and see where it takes you. Maybe you are like I was a few years back where I used to love having the surround channels turned up to make things seem more dynamic. I still run my surround a bit hot, but only a couple of dB. With my new theater under construction, it will be interesting to see how I tune it since it will be a more ideal room with sound control and treatments of the room itself. Maybe I've just been compensating for less than ideal room acoustics.