SPL help

Willow

I just went out on my lunch and bought the analog SPL meter,

I need your help

1-I don;t yet have a test CD it's on it's way
2-how do I use I need step by step (I will use pink noise tonight)

A or C weight ?
fast or slow response ?
what do I set the big knob to ?
then I turn up the volume on the reciever to what ?? the main volume ??

and then..???


thanks a bunch

steveinaz

"C' weighting, slow response. The main dial selects your dB level range; set it to the approximate range you'll be reading. You'll know if its set too low because your meter will be maxed out or the display will blink on the digital model. If its set too high, you want get any reading. Leave everything else at its default setting.

Typically you set your volume so that the 100Hz test tone is showing 83dB on your meter, which should be at your listening position when read.

The procedure depends on wether you're doing a 2-channel w/ subwoofer setup or if you're doing a surround set-up...

Willow

thanks

it will be surround. I know it should be at about 85dbls.

where am I to get the 100hz tone ?

so set all my speakers to 0 then go from there to reach the 85 right ??

so the big dial should be set to about 80 ??
and the meter should be at 0 when it's tuned or where ??


edit: and the mike is to be at ear level ?? in normal sitting position ??

steveinaz

Bud, I only know the 2-channel/sub setup; You'll need one of those surround guru's for help on surround setp.

You want the mic at the primary listening position. For instance, I typically sit on my couch, I laid the SPL meter on the top of the couch back, centered on the couch facing my main speakers...

Willow

ok thanks !! and It's the analog meter not digital.

Pauly

the skinny from Doc

1) Set all the individual speaker volume controls on the receiver to 0. Set the sub volume control to -5.

2) Play the center channel test tone and measure the SPL AT your listening position.

3) Adjust the Master volume on the receiver until the test tone for the center channel speaker is showing 75 dB on the SPL meter.

6) DON'T touch the Master volume ANYMORE, and write down the Master volume setting.

7) Switch to the test tones for the mains and surrounds and adjust the individual speaker volume controls on the receiver (NOT the Master volume) until they also read 75 dB at the listening position.

8) Switch to the sub test tone and adjust the plate amp volume control AT THE SUB (NOT the receiver Master volume, and NOT the receiver sub volume, which should be left at -5) until the SPL meter reads about 75 dB at the listening position. If you like your bass a bit on the hot side, adjust the sub amp volume control until you hit 78 dB at the listening position. The bass tone will fluctuate some on the SPL meter, so try to take an average.

Your system is now properly calibrated, and the Master volume setting you wrote down will get you pretty close to reference level SPL peaks for both surround sound and bass.

When measuring output, also consider the inherent rolloff of the RS SPL meter. Add the following to the meter’s readout to get an accurate SPL.

16hz/11dB

20hz/7.5dB

25hz/5.5dB

31hz/3.5dB

40hz/2.0dB

This meter rolloff also affects the calibration levels. The RS meter tends to read about 2dB low during the typical subwoofer calibration tone. So 75dB on your meter is actually about 77dB or 2 dB "hot". If you go for 78 dB, you will be 5 dB "hot".

This is not a problem at lower listening levels, but if you play it at "reference", you might bottom or bust the sub unless it is particularly robust.

Also, LOTR is mastered very loud, so don't try that at reference.

Doc


__________________

Paul

Willow

thank you very much !!!

Dr. Spec

The above was for internal test tones.

For a calibration DVD, set the Master Volume to 0.0 (if the scale allows that and most do) and essentially follow the same type of protocol.

Avia requires 85 dB, VE and DVE requires 75 dB.

DVE has a problem with the sub tone; it is encoded 10 dB too hot and is also very wide band. Most users get the best results with DVE sub level set to 87-88 dB as compared to 75 dB for the surround channels.

Pauly

Ah but of course...Willow what AVR you have? Does it have internal test tones?

Willow

yamaha rx-v540 and if you refer to internal test tones as pink noise than yes mine does

Pauly

there you go...no need to buy a DVD.

MikeT66

I did what was posted here set all my speakers to 0. Calibrated my center with main volume to 75db which ended up being a ref level on my master volume of 51. Then when I went to each individual speaker and got 75db at 0 on all speakers just had to turn sub volume down a little bit to hit 75db. Does this sound right that I didnt have to adjust my individual speaker volume on any speaker at all?? Just wondering if I did something wrong. How much do you guys usually have to tweek your individual speakers to reach 75db? Sorry if these are dumb questions, I am new to the HT world. Thanks for your help.

Pauly

Originally posted by MikeT66
Then when I went to each individual speaker and got 75db at 0 on all speakers just had to turn sub volume down a little bit to hit 75db.

Go back to 51 Master Vol then from there tweek the R/L and Surr's NOT USING the MASTER VOLUME but however using the speaker level adj..(-3, -2, -1, 0, +1, +2, +3 etc) till you get to 75DB on the meter..

MikeT66

Spasticpitbull, I did I am getting 75db at listening position on all speakers at master volume 51 without having to adjust them or tweak them any. With all speakers to 0 on receiver individual volume I get 75db. When I set center and master volume to 75db at ref level of 51 when I went to tweak rest of speakers all came in at 75db. No tweaking was needed. Just little on sub.

Pauly

good deal..consider your setup calibrated!!!

MikeT66

Spasticpitbull, thanks for all the help and being so patient with a newbie to HT. Hope I didn't bug you with stupid quesitons. Have learned so much on this forum. Thanks again.

Pauly

no prob, i am no expert and learn somthing new here all the time.

Dr. Spec

When I set center and master volume to 75db at ref level of 51 when I went to tweak rest of speakers all came in at 75db. No tweaking was needed. Just little on sub.

That is highly unusual; you got VERY lucky. (thumbs up).

Unless you are using a sat system with essentially identical drivers at each channel and all being almost the same exact distance to the SPL meter, the chances of hitting exactly 75 dB at each speaker without tweaking the individual channel levels are between slim and none.

Typical channel level variations will be in the +/- 3-6 click range to obtain a uniform SPL response at the seat on test tones.

Regardless, be sure to also set you distances to each speaker.

MikeT66

Dr Spec,

Might be because my basement is not really huge. 15ft wide 16ft long and I am pretty well centered around all speakers. I thought this was unusual also but I did it just as described and just had to turn my volume down on the sub itself a little to hit the 75db mark. It stayed at -5 setting as describe in post on how to calibrate and use SPL meter.