how to equalize center

[bismarck]

the post name basically staes my question. I honestly don't have the greatest ear, nor the audio experience to do everything blindly. My yammie reciever also doesn't have ypoa. I can notice the difference in test tones from my cetner to my mains, but i am not sure how to adjust the center to get the desired sound. I am trying to get them to sound the same, right? I am wondering if there are any guides or manuals or hints about adjusting it. Thanks

[AnalOg]

Hi,

You need to buy a SPL meter from Radio Shack, this will allow you to set all the channels at the correct level from your viewing spot.

Tom

[CECAA850]

The first thing you need is an SPL meter. RatShack has them at a reasonable price. Use the meter and your receivers test tones to set the levels for each channel. Make sure the SPL (dB) is the same for all channels at the seated position. If you want, you can buy a disc like Avia to help you. With your receiver set on "0" calibrate all channels to 85dB using the Avia disc tones.

[RichardP]

Do you mean equalize the overall level (volume) of the center (in

relation to the L & R), or equalize as in adjusting the frequency

response of the center to make it sound more like the front L & R

speakers? If the former, use the RadioShack SPL meter to calibrate the

volume of each speaker. If the latter, you may have to do it by

trial and error. My Yamaha receiver (perhaps like yours) has a

simple 5-band equalizer function for adjusting the frequency response

of the center (they assume that many users will have a center that is

different than the front L&R), but little in the way of guidelines

for using it. It may be all you can do to adjust the perceived

"brightness" of the speaker, which would mean twiddling with the two

upper frequency bands. Be sure to set the output/volume of the speakers

first, before you try to adjust the freq response.

[CECAA850]

Now I'm confused. I though that YPAO only autocalibrates SPL, and that's why I responded like I did. If it does some sort of EQ, than my response was off base. If your speakers are timber matched, I don't understand what he's trying to accomplish.

[ygmn]

I sugest getting speakers for the LEFT CENTER MAIN that are timbre matched...

and then setting output levels to the same SPL...

[bismarck]

i mean the frequency. I assumed that ypoa did that too, but if it doesn't, that is all my fault. I guess i didn't explain myself well enough. If only we were talking computers... From what i have gotten so far, it is just trial and error. The reason i started this post is because when i am watching tv, i like the sound of my tv much better than using my HT. I am not sure on what "timbre matching" is. Is it just making the voices and whatnot sound the same "and good"accross the center, L&R. If so, then that is exactly what i am trying to do.

by the way, i have the synergy b-3's and the c-2

[CECAA850]

According to the web site, the center that matches the B3's is the C3, not the C2. That may be the difference you are hearing.

[travisc]

I sugest getting speakers for the LEFT CENTER MAIN that are timbre matched...

and then setting output levels to the same SPL...

thats the only way, youll end up in the nervous farm trying to do it by ear. Get the closest timbre match and move on to the next thing

the best timbre match for example would be three of the same speaker, next would be a center designed to go with your mains

[tkot]

as stated above do the rat shack thing and then sit back and listen to a couple of movies(not the test tones)if it sounds ok the your in.

timbre matched speakers are the best way to go, but for some of us its too expensive or impractical. i use a combo of cornwall fronts, an rc7 center, heresy sides and rs35's for the rear. it sounds pretty good to me and my freinds all freak out and say its the best set up they've ever heard.

if your doing multi channel audio then i can see where timber matched speakers ar not really an option, but if your mostly into movies the set up is a little more forgiving.

as long as all your speakers can match the db level that works good for action movies your most likely ok.

and when you want to listen to music just put the recievers input to stereo and turn off every thing but the fronts.

jay

[bismarck]

hmm..... I see on the web site that the c-3 and s-3 are recomended. On a brochure that i picked up by klipsch from BB it recomended the c-2 and s-2.

[gbrlex]

I just purchased the Avia disk and haven't figure out how to calibrate the various channels. If the pre-amp/receiver is set to 0 when you start, do you use the volumne control on the pre-amp to reach 85db. If so, when you go to the next speaker do you return the setting to 0 and start over?

I would really appreciate a detailed explanation. I have the Radio Shack SPL,but thought the Avia disc would work better with my new SVS sub.

[strutter]

i may be wrong, but here's how i did it. using the test tones on the receiver and a RS SPL meter. i played the test tones and adjusted the system volume control until i got a reading of 80db on the meter (80db is just a reference point.)

then as the tone moved from speaker to speaker i adjusted the volume for that individual speaker in the receiver menu to 80db. LM, CTR, RM,RS,LS. the sub i adjusted using the gain on the sub but the menu has a volume control for this also.

i just got the rives test cd and have not had a chance to use it yet but leveling out the speakers and switching the phase on the sub made worlds of difference.

BTW i am using synergy F-3,C-3,S-3 ,SUB-12. and a Denon AVR-683 receiver.

hope this helps.

[travisc]

think different, you need both the avia and the spl meter. What kind of avr do you have?

[TheSoundBroker]

Your center channel should ideally always be as close as possible to the mains. The drivers should be as close to the same size as possible. In Klipsch, the compression driver should be the same. But even if you have the EXACT same speakers across the front (for example a triple RB-75 or KL-650 THX Ultra 2 setup), there are still things that can throw the center tonal balance off.

First off, if your left center and right are at different heights, it is important that the center be correctly aimed. This is one reason using a good acoustically transparent screen Screen Research is such a hugely great idea for a front projection setup...all your speakers can be centered on the screen and at identical heights. If your setup is like most, and your center is up higher or lower, it's alignment time. I use a laser alignment system to align all the speakers to the same acoustic center when I do an installation. If you don't happen to have a laser alignment system laying around, you can still do a basic alignment. Tilt your center channel up (if mounted lower than your mains), or down (if higher than your mains) in tiny increments and observe the effect. I've used pennies. Add a penny...listen...add a penny...listen...etc. You want to run the same signal to each channel to do this and you want to play something that is midrange oriented. Some high zoot pre/pros and AVR's have a party mode that sends identical signals to all channels and allow you to individually turn on and off each channel. Don't rely on the built in test tones to set the alignment...they often have intentional tonal shifts on them to help identify the different channels for setting levels. Remember, you want to send the SAME signal to each channel. If your reciever has adjustable bass management capabilities (i.e. you can change the crossover frequency for the center), definitely play with it...it can shift to tonal balance of the center quite a bit (try it with tan RC-7 if you don't believe me!)

The second thing is time alignment. If your reciever has an automatic delay setup and allows for center channel delay...use it...but DOUBLE CHECK it. This is easy. Start with your main front center seat location and measure from the seat center to the front of the left, right and center speakers. Note the difference. If your center is placed on the same plane as the left and right, it is CLOSER to you. If you have an automatic delay, look to make sure your center is correctly set. Rule of thumb is 1 ms for each foot. So if your left and rights measure 10 feet from your center seat, and your center channel measures 8 ft, you need a 2 ms center delay. If your reciever does *not* have the capability to set a center channel delay, you'll have to do it manually...usually by moving your left and right mains closer to you so they actually are on an arc.

Next thing that effects your center channel sound is your center channel environment. Is it sitting on a shelf or TV? Is the front edge of the center pushed back from the edge? If so, you have set up a big initial reflection point. Move the center channel so that it slightly overhangs the front of the TV or shelf. If you can't do this then an even better solution is to set the center on an acoustically absorbative surface and make sure that surface extends as close to the edge as possible. If your center is on top of a tube TV, this is the worst possible setup as you have just set your center right next to one of the most reflective acoustic surfaces on the planet...your TV tube. get a front projection TV. Anything you can do to minimize this reflection is a good thing Front projection TV.

Is your center placed inside a cabinet? Then chances are you have big time cavity resonance and this will throw the tonal balance off. The cabinet cavity should be lined with absorbative material such as lambs wool or rock wool. This means ALL sides of the cavity all the way to the front. If your S.O. objects to the look, then remove the center channel grille and create a new grill cover to encompass the entire center channel opening in the cabinet.

Your levels need to be correctly set as well. If you have an auto level setup system...use it but always double check it manually. This means a Rat Shack meter...preferably the analog model. Remember, your center channel IS your reference speaker. When you play a test tone, leave the center channel level set at zero level on your reciever and turn your main volume up until it reads 80DB. All other speakers key off the center channel for level. Switch each speaker on one at a time and change the level controls for those channels to read zero on the SPL meter. Your sub is typically adjusted to +10db (90 db on the meter). Remember...unless there is one seat in the room, check the levels at the different seating areas to make sure you don't have a big imbalance. If you find a huge channel level discrepancy between different seats on your front three speaker levels...congratulations and welcome to room acoustics. That is a whole other ball of wax that you should address if at all possible.

Last but not least, there is actual equalization, which is a last resort after all other avenues have been taken. This requires a *good* test suite and a *good* parametric EQ. Both which will cost more than the center itself. If you have a top line Ref, Heritage, Ultra 2 or Pro Cinema setup...maybe worth it, but with everything above addressed, not likely to be needed.

[boomer9911]

As stated, use a rat shack spl meter and do it through the Receiver for each speaker. I would recommend if you go to rat shack get the anolog over the digital spl ($10 cheaper also), I have heard on many occassions it's more accurate and I agree having used both of them(own analog myself), plus love watching the needle move...[]