Axiom Home Page Forums General Discussion Home Theater my nightmare,

Also, reading through most guides on calibration of your HT they say that you should calibrate at the listening position not dead center of the room. I would agree with with this as you tend to be closer to your rear effects in the listening position then dead center. If you calibrated your system with the SPM at dead center of the room then the levels of the rears and surrounds would be set too high.

Johnny and Alan, I tried my HT calibration to 85db but it's too loud and I max out some of the speaker level to +15db...maybe I am doing something wrong. anyway..this is how I've done it....and could you please tell me exactly the steps by steps if I did it really wrong...

There are 3 parameters involve on the receiver settings...
1. Master Volume
2. Individual speaker volume(this volume is set to ref volume when the receiver test tone has been run. this is the volume that was being set if you need to increse/decrease the volume, and not the Master volume).
3. Individual Speaker db level (min -15 max +15 db)

here's the actuall step:
1. set master volume to ref volume (0db)
2. run the receivers test tone
3. adjust the speaker level (not the volume) until SPL measures approximately 85db

after this settings, my systems sounds soooo baddddd....so I have to adjust it back to 75db....is this the right thing to do? S&V says, for 75db, you need to adjust first the volume till SPL measures 70db before calibrating the speaker....and in order to achieve that I have to run the receiver test tone, then increase the volume for each speaker to achieve the 70db on SPL (at this point I can't see the relavance of setting the master volume to ref level, since during test tone as I have said above, the volume I am increasing to achive the 70db measurement on SPL is the individual speaker volume). It looks like the process is run test tone, increase the speaker individual volume to achieve 70db on SPL and then start adjusting the speaker db level to achieve 75db.... is this how it;s done??? If this is the case, then why do we need to set the master volume to ref volume first? and also if this is the case, that means my setup is not really calibrated properly.....:-(....oh btw, it;s okay to use the internal receiver test tone right? or I should use the test cd's (S&V) test tone which is a little lower volume that my internal test tone.....

thanks.....

Hi,

I've never heard of anyone advising calibration at the room's dead center. It makes no sense unless you sit there. Given the vagaries of standing waves, you could calibrate there and then find the subwoofer balance would be totally wonky at your seating location. Not to mention the settings for the surround levels and left and right mains. Technically, if there's a couch, you should calibrate for each seating position along the length of the couch, average the settings. . and ..You see what I mean?

Calibrate only at your seating position and hope the sound is reasonably consistent for other locations. It usually is if the room or setup isn't too eccentric.

Regards,

Hi Alan,

That’s my thoughts exactly, I have never heard of as Johnny says trying to calibrate at dead center it does not make any sense as this is not as you correctly state where you sit.

(Sorry guys for the long post)

With regards to the reference levels, I have just been on the phone to a THX certified installer a gentleman by then of JP was kind enough to let me pick his brains for about 45 minutes. In a nut shell, with regards to calibrations this is the what he said about the 85 vs 75db. 75 db is the calibration guideline for theater, for music the guideline is 85db. The reality is that we listen to a mix of both and unless you have a dedicated theater room there is really no right or wrong. If your manual states 75db (as does my Denon) that is where it was calibrated to at the factory and the levels at which their THX certifications were done. JP also stated that he will change the calibration value for a given room depending on the size and response (live ness) of the room. As for using the meter, Digital is fine, make sure that the meter is set to “C” weighted and slow response. The meter should be placed in your seating position (not dead center) and the meter held vertically not horizontally. If you do not have any way to hold the meter in this position then stand behind your seating position and hold the meter at arms length so that it is in roughly the same position as you would be when seated. You should also sweep the meter left to right and adjust for an average of 75db, or an average of whatever level you are using, again be sure that the meter is held vertically.

I hope this helps

Regards
John.

Sorry Un if I am using this post for something else, but I really wanted to know the proper steps to calibrate the speaker as I have mentioned above....Alan, John anybody, please help, need your response from my post i mentioned above....thanks!!!

Sean,

The correct procedure is to set your volume to any level to begin with, turn on the test tone, rotate the volume to the 0db position, refer to my last post, for details about correct positioning for you and the meter. Adjust individual levels to get to 75 or 85db as you so desire. If you say that 85 does not sound good with your setup then use 75. make sure that you hold the meter correctly and sweep it from side to side and adjust for an average reading.

Hope this helps you.

John

Just want to be clear about turn the volume up...is this the master volume or the individual speaker volume....? The thing is, once I run the test tone, and if I wish to adjust the volume, the volume that I am adjusting is not the master volume but the speaker volume....and as I run the test tone, the volume for that speaker is already started at ref volume 0 db. That;s why I am a littel confuse, specially when setting the SPL first to 70db (or putting the SPL needle to the center (0)) before calibrating to 75db. any thought???/

If that is the case with your unit then you need to set the master volume first to the 0db position, ignore the meter at this point. Then turn on the the test tone and now using your meter from your seating position, adjust the indivdual speakers levels, center, FL, FR, RS, LS, etc.. to get 75db for each speaker channel individually.

Let me know if you need more help
John

I will say this, whether calibrated to 75 or 85 my Axiom setup (M60, VP150, QS8) sounds great. I just re-calibrated everything to 85db and there is no discernable difference in sound quality. Thanks for the additional info John and Alan!

Heath

Thanks John, this is actually how I'm setting up my HT actually...but with this steps, I'm having problem calibrating it to 85db as my speaker db level already reaching the max +15db adjustment and still the SPL only records between 80-83db.