your systems output aveerage SPL

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JRace

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Re: your systems output aveerage SPL
« Reply #20 on: 30 Jun 2010, 07:28 pm »
Nor am I convinced that the SPL readings favor the bass.  I've read reports of orchestra members, esp. those sitting in front of the brass section, suffering from NIL. 
SPL meters measure peak sound-pressure levels, which will be the loudest sound, regardless of frequency. What you will find with most music playedback in most home stereos is that the bass is the loudest that we hear.
Quote
If you are listening at 80dBc average, given that the peak to mean ratio for CD recordings is claimed to be 20dB, and that is typically only in classical recordings, I wonder if you are really hitting 100+dB peaks.  It's the plus part that I'm having a hard time with, there just aren't that many recordings with that wide of a dynamic.
I should have clarified, this is for movie playback. And I prefer to run my subs on the hot side.

bunnyma357

Re: your systems output aveerage SPL
« Reply #21 on: 30 Jun 2010, 09:02 pm »
It probably would be helpful for people to list what they are talking about when they mention SPL. I have my system calibrated so that when I say average SPL is 75 dB, that is the volume level where a -20 dBFS pink noise signal measures at 75 dB on a C Weighted Radio Shack SPL meter at the listening position. I also use acoustic treatments and parametric EQ that minimizes room modes, so that a peak in bass won't skew the readings (too much).

Just curious how others are arriving at their SPL values, since we are probably comparing apples & oranges.


Jim C

JRace

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Re: your systems output aveerage SPL
« Reply #22 on: 30 Jun 2010, 09:11 pm »
My measuring rig consists of:
RadioShack SLP meter
Berhinger ECM8000 measurment mic
Room EQ wizard software (REW)
Laptop with external USB sound card

Playing pink-noise from REW I set the Denon AVR's volume to obtain 75dB SPL C at the listening position. Then using REW I will measure response from 0-200Hz, and set the manual EQ on my MartinLogan Descent i sub to reduce any room nodes, then I run Audyssy to flatten the rest.

Afterwords I tend to increase the LFE level by3-4dB to my personal tastes.

In many rooms the room nodes will cause peaks in the bass region and it is these peaks that will give you your max SPL reading.

At work I have a nifty machine that takes SPL readings at the ear-drum. Too bad it only does 125Hz - 8000Hz.

Mag

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Re: your systems output aveerage SPL
« Reply #23 on: 30 Jun 2010, 11:42 pm »
It probably would be helpful for people to list what they are talking about when they mention SPL. I have my system calibrated so that when I say average SPL is 75 dB, that is the volume level where a -20 dBFS pink noise signal measures at 75 dB on a C Weighted Radio Shack SPL meter at the listening position. I also use acoustic treatments and parametric EQ that minimizes room modes, so that a peak in bass won't skew the readings (too much).

Just curious how others are arriving at their SPL values, since we are probably comparing apples & oranges.


Jim C

As I wrote before spl's A or C weighted can be misleading. Myself I'm generally referring to the average volume on the spl meter A weighted, not the peak transients.

Like some cds the C measurement is 95 db the A measurement is 85 db. But I can tell you that in my room it is above voice level. So it perceived at around 92 db A weighted. However on other cds I can get an equal reading in A and C weighted (can't remember which cd that is off hand). It really depends on the recording.

You know a reading of 95 to 105 db C weighted is a lot of bass output. Think of walking into a bar, the first thing you hear if a rock band is playing is the bass. That's the kind of bass Vettemanbc is generating with his system. 8)

JRace

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Re: your systems output aveerage SPL
« Reply #24 on: 1 Jul 2010, 01:44 am »
A-weighting trys to emulate our hearing curve (http://en.wikipedia.org/wiki/Fletcher-Munson_curves

The midrange is boosted and the highs/lows are rolled off.
This is accurate at low levels, yet disregards the fact that our hearing curve is not linear, it changes with intensity.

More importantly to all of this discussion is the fact that there is little real data on music-induced hearing loss. Noise is quite different than music, and we know some (but not enough) about the effects of noise on our body.

It is well known and accepted that your stress level impacts your ability to deal with and recover from damage.

I for one find work to be stress-inducing, and music to be stress-relieving.
 :eyebrows:

vettemanbc

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Re: your systems output aveerage SPL
« Reply #25 on: 9 Jul 2010, 01:46 pm »
A weighting measures 500 Hz to 10 KHz used to measure noise

C weighting , 32 Hz to 10 KHz used to measure SPL of music

the RS digital SPL defalt is C weighting

RS SPL measures BOTH continous average SPL and continous MAXIMUM SPL, defalt is average

I used C weighting  because the RS meter onwers manual  so directs, and my crossovers use C weighting for set up.
 Really shouldnt we all? You are all useing the RS digital, any one read the manual besides me?

the charts are A weighted, for noise, not for music.

also the 2000 watts (times two) is the rated maximum continous minium, I never use close to the max min, (obviously the minimum continous  output is 0 watts) volume turned down