"sound level meter" question

[tattoo_Dan]

I bought a RS digital sound level meter(33-2055) today,to use the level calibration on my AVR,

I have a tri-pod to use,what is the best way to measure the sound?

1)on a tripod pointing up at the ceiling in the main listening seat?

2)or hand held pointing at each speaker that is making sound from the main listening seat ?




3)what Db level is good ?
*I have them at 74 right now,with the unit facing the ceiling*

4)should I place the unit in the main seating/listening position?
or in the very center of the room?

 

[j_garcia]

Calibration needs to be done from the listening position. Pointed up toward the ceiling is fine. You do not point the meter, each speaker needs to be measured the same way so that the readings are taken the same way.

75dB is the standard and is most likely what your receiver's test tones are and what they are intended to be measured at. There is a DVD by Ovation called Home Theater Tune Up and it walks you through the setup with an SPL meter.

 

[Savant]

Try this thread, too:

http://forums.audioholics.com/forums/showthread.php?t=39582

 

[jostenmeat]

Try this thread, too:

http://forums.audioholics.com/forums/showthread.php?t=39582

Nice to see you here again, Savant.

I'll see you in another two months?

 

[Exit]

I did not have the time to read the referenced threads but I wanted to mention that you should look for an excell spreadsheet that plots frequency response using the appropriate RS digital meter correction factors to get more accurate results than a direct meter reading. I use the RS analog meter with such a spreadsheet but I believe the digital meter may have different correction factors.

 

[Savant]

meat: If you're referring to my seemingly infrequent contributions, I try to stick to what I know. Threads about how to program this remote or that DSP or which in-wall loudspeaker is the best or whatever are not my cup of tea. I do what I can!

Exit: To clarify, you're talking about frequency corrections to use when reading the sound level of tones, correct? If so, no need to look for any special spreadsheet. Any good acoustics text will have A- or C-weighting corrections for all the 1/1- and 1/3-octave bands. In fact, there's an online calculator here. Just enter the frequency of the tone and it will show you the correction being applied for A- or C-weighting. Add this value* back to the reading on the meter (analog or digital) to get the flat sound level in dB. (Note that this assumes the sound level of the tone is significantly above the background noise level in the room. If there's little/no change in sound level with or without the tone, the sound level of the tone is not being measured by the meter.)

*The absolute value - not the negative value shown. The tool is actually assuming the user wants to do the reverse of what we're talking about, that is, the tool is meant to be used to change a flat measurement to A- or C-weighted. Thus, we need the negative of the negative, or the simply absolute value, to add back to the number on the meter. Sorry if any of this is confusing. Of course, for C-weighting, most of the corrections are going to be very small. So knowing / doing all of this is not critically critical. Example: for 80 Hz, we would be adding 0.5 dB back to the measurement. No big whoop, IMO.

HTH.