I do not know if this is the right place to post this question but in any event any kind of assistance would be helpful.
I recently bought a new Home Theater speaker system. I thought it would be interesting to calibrate my system myself.
I bought a Galaxy Audio CM140 SPL meter. Can someone give me a step by step tutorial on using an SPL Meter.
I am not sure if I am doing it correctly for one thing, and second what am I exactly looking to change? The placement of my speakers?

My Sub is the Fathom 113 and it has it's own calibration unit on it and I was told that it is pretty reliable so I am going to let it do it's own thing in the beginning.
I am not the kind of person to get things like this right away especially when no one is directing me whether I am do it correctly. Once I can understand some kind of direction I feel that I will be sucessful in calibrating my system.

Thanks for any kind of assistance.
Frank

I don't have the SPL meter you do I have a Radio Shack analog meter but the principle is the same. First you should measure from the "sweet spot" in your room. If your single this is where you usually sit. If married where your wife usually sits.

I'm not sure if you have a 990 yet but you would go into your pre/pro or receiver's setup menu and go to "calibrate speakers" or "speaker level". You'll need to know the reference level for your receiver or pre/pro. You set the meter to the desired db level, usually 70 or 80, and then you hold or place the meter in the sweet spot, preferably at listening position, set your volume at the reference level and run through the test tone on each channel setting them as close to "zero" as possible.

I don't give instructions very well and I'm sure someone here can be more precise but that's the general idea.

I have the 990/7700 prepro.
Should I set the the decibels settings on the 990 for each speaker to 0 when first starting? How do you determine the reference level? When you say set the volume at the reference level do you mean on the 990 volume control?

Thanks in advance.
Frank

Normally, use the left front speaker as your reference. Once you set it to what volume you want, i.e., 75db on your meter, then adjust the trim of each of the other speakers to match the 75db mark. Do NOT use the volume control except for on the front left channel. When you have gone through the volume trim on each channel, and they all match at 75db, then you are set. You can also use a higher or lower reference level than 75db.

The 990's manual has a good run-through of how to calibrate the system using a meter. When using the 990's internal test tones, you want to set the master volume to 0dB and adjust each channel to hit 75dB on the meter. Since you're starting out from scratch, leave each channel at 0 until you start adjusting.

The reference label is not sacred. For example, really efficient speakers might lead you to set each channel trim down between 5dB and 10dB - in that case, you could safely adjust all eight channels up by the same number of dB.

What your trying to do is adjust the speakers so that they are all producing the same volume, this
will make surrround more balanced.
If your still not getting the drift of what you need to do, I'd recommend latching on to an Aviva
set up DVD. They give you very straight forward instructions on how to use the meter snd balance your speakers and the disc provides test tones also so you can calibrate to what your DVD player and the 990 are doing togeather. This isn't always the same result that you get just using the 990 test tones.
Good luck and enjoy fiddeling. Getting the speakers properly balanced can make a huge difference in system performance.

Ok Gonk, I went the on line manual. Sounds pretty basic and cleared up some things for me. tell me if I am starting this correctly.

Set the master control volume on the 990 to 0.

Go to channel calibration. All levels set to 0db's

Turn on spl meter and set to slow and c weight.

Now from here I have some questions. I have a Galaxy CM140 SPL Digital meter. There is a level selection mode,
Lo=32 - 80dbs
Med=50 - 100db
Hi=80 - 130db
Which one do I use?

Second, the digital cm140 cannot be adjusted manually to a 0 setting. Do I ignore the zero setting and make adjustments using the channel calibration until the meter reads 75db's.
The meter has a range from 32db to 140db at frequencies between 31.5hz and 8kz.

Thanks

Sounds like you're on track. It's really not as hard as people sometimes expect it to be.

You'll probably get best resuts by using "Medium" since you are focusing on the 70dB to 80dB range and that puts you right in the middle of the range.

You don't need to "zero" the meter - you just need to set it to a range that will let you see 75dB and adjust each channel's trim on the 990 to get a reading of 75dB.

You also want to use 'C' weighting, and SLOW response on your meter.

I saw the specs on this meter, quite a nice unit.

It is also recommended that you put the meter on a tripod, facing up, not directly at a speaker. Set it up at your sweet spot, and read the meter from a few feet away to keep your body from interfering with your readings. Keep the 990 remote in your hands, and have fun!

Could you first run the calibration with the 990 mic, then compare the results with your meter? I'm curious just how accurate the 990 auto cal is.

I've heard it recommended that you take the measurements with the room set up as you would with normal use, including you sitting in your normal seating position and hold the meter as close to your head as possible.

Works well for me at least.