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Foolin' around with the RS SPL meter [message #51670] Sat, 05 January 2008 04:23 Go to next message
Bill Epstein is currently offline  Bill Epstein
Messages: 1088
Registered: May 2009
Location: Smoky Mts. USA
Illuminati (2nd Degree)
Took some SPL readings at 1 meter between the speakers with the Stereophile test CD with the meter set at "C" weighting 'slow', 80dB.

Using the corrections on the Audiogon board by Sean:

1k 75dB
200 77
160 79.5
125 81.5
100 84
80 83.5
63 79.5
50 77.5
40 76.5
25 75

Ambient noise level seems to be about 50dB. The increase between 80 and 125 Hz is at a point a little higher in the spectrum than I would have thought. +9dB at 100 Hz is a little odd? Room is 15x28x8 with lots of stuff in it.

Does any of this mean anything?


Re: Foolin' around with the RS SPL meter [message #51671 is a reply to message #51670] Sat, 05 January 2008 09:37 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
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Registered: January 2001
Illuminati (33rd Degree)

That looks pretty good to me, Bill. In room response good to 25Hz and less than 10dB variation from 25Hz up. Response flat +/-5dB. When I measure stand-mounted studio monitor type speakers, I usually see a 15dB+ dip just from floor bounce, even if measured outdoors. A tight room with solid walls like a basement gives almost 20dB room modes. Rooms with framed drywall construction aren't usually that bad because the walls have some "give" and tend to damp the modes. So you can expect less peaky room modes in rooms with drywall walls. All in all, I'd say your response looks pretty good.


Re: Foolin' around with the RS SPL meter [message #51672 is a reply to message #51671] Sat, 05 January 2008 09:48 Go to previous messageGo to next message
Bill Epstein is currently offline  Bill Epstein
Messages: 1088
Registered: May 2009
Location: Smoky Mts. USA
Illuminati (2nd Degree)
Put that way it does seem good. The Owens-Corning panels and piles of R-13 rolls in the corner, along with the drywall works well.

Funny thing about the 30 and 25 Hz readings. Sound seems much softer than the next higher ones but the meter says just as loud.

Infrasonic bass [message #51673 is a reply to message #51672] Sat, 05 January 2008 10:27 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18791
Registered: January 2001
Illuminati (33rd Degree)

You're right about bass under 30Hz, especially at moderate listening levels. Deep bass isn't so much heard as felt, and you really need the power levels to be high enough to vibrate your body for infrasonic bass to be noticed. Below 30Hz or so, it stops becoming sound you hear and becomes more of a tactile sensation. See the Fletcher-Munson curve:



Re: Infrasonic bass: WOW! That's an eye-opener!* [message #51674 is a reply to message #51673] Sat, 05 January 2008 10:54 Go to previous message
Bill Epstein is currently offline  Bill Epstein
Messages: 1088
Registered: May 2009
Location: Smoky Mts. USA
Illuminati (2nd Degree)


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