I currently have my setup in a 13x15 room. I'm using an Onkyo 605, Boston 10" sub, 4 Bose 301s for the satellites and a Bose center channel. Before the Bose haters start please let me first say that I got them for next to nothing from work so they were a logical choice rather than spend a couple thousand on Paradigm's or Cambridge. But I've tested each pair as well as the center channel individually and they are fully capable of producing clear, separated sound by themselves. So that's not the ultimate root of my problem.


Anyway, I have these speakers placed in a standard 5.1 configuration, and during mellow/dialogue heavy movie scenes things are fine. However, during very chaotic scenes (ie: car chase in the 2nd Matrix film), channels and details start to blend into each other and the separation is just not there. I am also sitting about 6-7 feet from each speaker if that helps. My question is this:

Is this due to the fact that I have relatively large, high wattage speakers so close together and am sitting so close to them? Or is it the setup itself? Just wondering how much of an influence people have found room size to have on sound quality/separation.

Any help is appreciated! :)

1. The room acoustics probably are not the best. Have you done any treatments?

2. The speakers are probably not capable of clear undistorted sound at those volumes.

The distance from the speakers should not have any real effect.

I haven't done any treatments so to speak. The setup is basically in a den area. Also, the volume was up pretty loud, around 75/100. I'm more or less a volume addict and unless I feel like the sound is going to knock me over, I'm not satisfied, especially with action movies. Unfortunately though I don't have a large room to spread them out and try them in so I'm limited to what I have right now (I'm in college and living at home, so while I'd love to take over my parent's basement, I can't :D )

Basically, the sound is acceptable (and pretty crisp) most of the time, but when you have music, smashing glass, crunching metal and dialogue all on top of each other at a particular moment, the speakers seem to struggle a little bit. And it's not audio compression either because I only use the multichannel PCM streams from my Blu-Ray and HD DVD players, and most of the discs are either TrueHD encoded or native PCM.

The scene you refer to I was looking into. Definitly you would require some heavy bass trapping to get improvement in that scene. There is not much heavy surround sounds at the start when they are leaving the garage. It then goes into very wide soundtage from above the cars with wind and occassional gunshot wizzes or fire. The music starts to fade in from a very close area and the instruments seem all blended into a single space. Then they arrive at the highway and the surrounds seem pretty on the light end, while the music grows larger, and bass becomes more intence. There is alot of crisp sounds until they cut back to to the operator, then mostly the entire surround stage is dominated by music while most action is also very wide accompanied by very tight bass. Then there is lots of back and forth when everything mostly is focused into the center channel area until Morpheus is out of the car. Then it goes to the highway again with some heavy subsonic (for some) sounds and with light surrounds. About the time trinity gets on the bike, there are very crisp and well defined areas and the music has a significant presence across the entire soundstage. Bass is going from the surrounds into the front almost like falling into the soundstage. This continues while they are very fast wide angle sounds with more chest hitting midrange bass, mixed in with more subsonics. The midrange gets heavy and more complex ambience that eventually fades back into the musical clarity and things become very visual on screen.

What I think would be occurring in that scene is probobly in direct relation to your subwoofer, settings, and probobly the center channel placement as well. I think I hear what you mean by speakers struggling. It's probobly because of all the midrange going on. Might try fine tuning the speaker distance or settings, move speakers away from the walls a bit.

Sounds to me like you need room treatments (most rooms do) and possibly more power since you're a 'volume addict'. Your amp cannot supply enough power for the more dynamic scenes when you've got the volume jacked up.

Make sure you've level matched your fronts/center/surrounds as well.

Have you experimented with placement of your sub? That can make a substantial difference in sound quality.

Sounds to me like you need room treatments (most rooms do) and possibly more power since you're a 'volume addict'. Your amp cannot supply enough power for the more dynamic scenes when you've got the volume jacked up.


The amplifier is probably fine.

I was in a bit of disbelief after reading about room acoustics and speaker directivity where the math suggested that at 2-4' from a typical speaker in a typical room the reverberant field was as strong as the direct field so moving arbitrarily far from the speaker couldn't drop the SPL more than 3dB so I got out my HP True RMS volt meter, SPL meter, and ran pink noise into my speakers.

Disregarding thermal compression I'd reach Dolby Reference Level peaks on most recordings with 50W into the center channel and 60W for the corner loaded sub woofer (good for nearly 10dB over its free space performance). A lot of people are under the impression that reference -10dB is actually loud (it sounds that way with a lot of distortion) which would reduce the requirements to 5 and 6W respectively.

The speakers most definitely are not up to the task. Many home speakers can't move enough air period, and small (this is relative, as in 2-ways with 6 or 7" mid-bass drivers) affordable ones don't remain linear enough over the distance they do move to sound clean.

Calibration would be the first step. Moving the sub around couldn't hurt but most speakers just don't have enough distortion free output at higher (arguably modest) listening levels.

Thanks for the help. There's no much I can do about my setup right now space wise, since I'm still in college and don't have my own house. Once that becomes a reality I plan on building a well planned home theater. Right now though, I guess I'll have to live with it. The speakers and Amp I have are already more expensive than most people would ever spend period, so new equipment that responds better to higher db is out of the question right now. I may try moving my sub though and see if that does anything.

Are you LCR's up against the wall? If so, move them out a foot or three. Is your sub in the corner? Move it away from the wall. Is the bass overwhelming? Turn the sub down. Add some bass trapping to the corners and/or some absorptive material to the floors.