Center channel volume questions

[ChrisJam]

Hi,

I'm new to 5.1 sound, and just got my system set up. My new center speaker was louder than my 10-year-old mains, so I had to decrease the center's volume with my amp's menus. Lowering it 3 db seemed to do the trick. Can you tell me, please, what might have caused this imbalance? Could it be that the new center speaker is simply more modern and more efficient? The center and mains are all 8-ohm speakers (as are my surrounds).

The center seems to be a decent match for my bookshelf mains tone-wise, though its sound isn't as full (the center is brighter). I guess that's a given, since my mains have an 8-inch woofer and the center has two 5 1/4-inchers. (The mains have two tweeters each, and the center has one. I don't quite know to make of that.) Actors' voices sound good--to my ear, that means rich and clear, yet not overblown--on this center when playing a DVD movie.

In case you wonder, I realized that the center was several feet closer to the prime listening position than my mains, so I set the center for a 3-ms delay to compensate.

Here's my equipment:

• Yamaha HRT-5280 amp (equivalent to RX-V800), 100 w/ch

• Eosone RSF-200 mains (48-20,000 Hz), set to small; Eosone was a 1990s spin-off of Polk & Genesis

• Yamaha YST-SW315 sub (20-160 Hz)

• Polk CS1 center (55-25,000 Hz), set to small

• Polk R15 surrounds (60-24,000 Hz), set to small


I'm trying to learn more audio systems, and this might turn into a real hobby for me. So please feel free to give answers that might stretch the limits of what I know as a HT newbie who only had 2-channel stereo until a week or so ago.

Thanks,
Chris

 

[MDS]

There are a number of possibilities for why the center was louder:

- Sensitivity of the speaker. If the center is rated at 91 dB/1W/1M sensitivity (meaning 1 watt of input will produce 91 dB sound pressure level 1 meter from the speaker) then it will play louder than the other speakers if they are rated at say 89 dB.

- Distance to the listening position. If it is closer than the other speakers you may get more of the direct sound reaching your ears before the direct sound from the other speakers.

- The room itself. Sound bounces all around the room and you get some direct sound that reaches your ears without bouncing off anything and then you always get reflected sound as the sound bounces around the room and hits walls, ceiling, furniture, etc. The combination of direct and reflected sound from the various speakers may make one or more of them sound louder than the others.

- Channel levels in the receiver. They may not be balanced, with the center set higher than the others. The purpose of using the test tones in the receiver to balance the channels and properly set the distance to each speaker so the receiver can apply time alignment (delay) is to get the level of each channel to be about equal. Time alignment and level settings will help to overcome the case where the sensitivities of the various speakers differ.

Get an SPL meter from Radio Shack and calibrate each channel to be about the same level (+/- 1 dB) and that should greatly improve things.

 

[Sheep]

Don't forget that the center Channel usually points right at you, so it isn't off axis. That can also increase the SPL.

SheepStar

 

[mtrycrafts]

Hi,
I'm new to 5.1 sound, and just got my system set up. My new center speaker was louder than my 10-year-old mains, so I had to decrease the center's volume with my amp's menus. Lowering it 3 db seemed to do the trick. Can you tell me, please, what might have caused this imbalance? Could it be that the new center speaker is simply more modern and more efficient? The center and mains are all 8-ohm speakers (as are my surrounds).


Thanks,
Chris

Try to invest in a sound pressure level meter from Radio Shack; get the analog one, around $40. Then, use internal test tones and level match all the speakers for best setup.

 

[ChrisJam]

Thanks for the advice, everyone.

MDS, your tip about the sensitivity is good. I hadn't known what to do with that spec before, but now I do, thanks. BTW, My Polks (center and surrounds) are 89 dB, and my mains are 87. Also, you mentioned the room itself. Except for the center, none of the speakers point to the optimal listening position, which means their sound runs into wall hangings and curtains, plus it gets bounced around some walls and off furniture. Now I can see how that can kill some of the sound.

Sheep, I can't believe I missed this one! Now that you've said it, it's obvious!

Mtry, thanks for the recommendation about the meter. You, too, MDS. I'll see what my local RS carries.