Calibration w/meter...am I doing this right? (1 Viewer)

[Hugh Scrivener]

OK...I've had the Sony DB-940 for a year and a half and I'm finally getting around to metering it. Pretty much been going by ear til I joined the community here. This is what I did...borrowed a meter from my employer, it has an auto setting that begins the scale at 40db, has a fast and slow setting and a peak hold feature. I havn't bought a disc yet...can it be rented at Blockbuster or Holoywood, so I used the tones on the amp. From what I understand as each channel plays I should be reading 75db on the meter..right? Now to adjust the levels of each speaker I should use the left/right balance controls for the front and rear channels and the center and sub are leveled using the center and sub +/- adjustment. At no point I should touch the Eq. as it will adjust power to each of the speakers by the same amount i.e +2 on front bass will give both speakers a +2 boost. Am I understanding this correctly?

 

[Vince Maskeeper]

Hugh,

Sounds pretty much right to me.

-V

 

[Hugh Scrivener]

Ok...after playing around some last night I discovered... to achieve 75db from the speakers using the test tones of the amp at my listening position I was using a higher volume setting than I ever have, approx. 5.5 on a 1-10 scale. Once I got the hang of what I was doing it was easy to get all speakers to stay in this range, however there was some fluctuation....74.8-75.3 or 4. This is my new question....at a setting of 3 on my amp(1-10scale) TPM hit a high of 101.5db....during the opening credits, is this normal? I'm scared to see what would happen if I used the 5.5 vol setting from the calibration....my cul-de-sac would probably turn to liquid earth. Does this sound correct? I know everyone recomends a test disc...are these tones 'louder' than the amp tones..causing the amp to peg 75db at a lower vol setting? I've heard people say they peg at 85db....does it matter if I use 75db or 85db?

 

[Vince Maskeeper]

Hugh,
You should understand that REF LEVEL is a strict measurement of output. The volume position, while related to output, can't be a stict universal quality in determining ref level, as a given volume knob position will offer one amount of output in a certain room, but will seem like less in a larger room.
The REF LEVEL is, essentially, 105db of SPL out of any given speaker, maximum. Regardless of volume knob position, this is what ref means.
To determine ref level, someone could supply you with test tones created at absolute MAX level, and you could balance your system to 105db with these tones. However this would suck, and be painful on the ears.
So they created tones a specific number of steps below ref for you. The tones on AVIA are 20 steps below max (max should be 105db, so 20 steps below would be 85). The tones on VIDEO ESSENTIALS are 30 steps below max (max should be 105db, so 20 steps below would be 75).
But, in your case, with receiver tones- there is no real way to tell how many steps below max they are. So, there is no way to get an accurate number on what "ref" level is from those tones without knowing.. So that 75db level you calibrated with your tones might be some arbitrary point- and might actually be higher than ref level.
So you now have your speakers balanced- but I would certainly get a calibration disc to double check everything and determine actual point for Ref.
-Vince

 

[Vin]

So you now have your speakers balanced-

Assuming the receiver's test tones were the same volume for all channels (which isn't always the case). If the tones varied in volume from channel to channel, not only would you not know where reference is, you also would have an unbalanced system if you set them all to say, 75 or 85dB with the SPL meter....correct?

Vin

 

[Hugh Scrivener]

OK...heres where I stand...after watching several different types of movies, action to drama, and from my two available sources(fortunate enough to live on a kick-a** cable system w/ 5.1 on many channels...big ups to Adelphia) with just simply balancing the speakers I have noticed a really big difference. What I thought was good has become better. I'm kicking myself for waiting so long to do this. A friend and I are working out a 'you buy the disc, I'll buy the meter' deal. If it gets any better I might not leave the house.

Anyone who reads this who hasn't calibrated, to some degree, log-off and do it now!!!