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SPL meter results relative to Magnepan's (supposed?) craving for power/current

Hi all...
My thoughts are; if my ambient/background level is about 40dB and readings of "music" at my typical SPL from my listening position show about 75dB, that means that what I'm actually hearing is mostly noise and not my Maggies? Surely yes... Right? 

Even though my Maggies are in a very big room, do I need to rethink my amps power output of 400 WPC if I prefer a lower listening level? Overkill? I understand the benefits of "headroom" and amp/speaker "synergy".

At which SPL do your Maggies wake up and sing?
Thoughts? Comments?

Thanks!
mkh1099
millercarbon's avatar
millercarbon
12,531 posts
 
You’re looking at a meter to see the difference between music and noise? I can’t hear your system. Does it sound like noise to you? If you can’t hear the difference what are the odds the meter will?  

Anyway technically no, not even close. Sound pressure levels are logarithmic. 40 is more than half of 75 in linear terms. In log terms 40 is closer to a thousandth of 75. In other words not even close.




tomic601's avatar
tomic601
12,866 posts
 
Let’s sort it out with real help.

40 db of background noise in the room, at what frequency?

chances are it’s not broadband noise, so your real music signal to background noise is probably better than 35 db, which is not awesome. At this listening level, you are probably overpowered….but

How far away from the maggie are you taking the SPL measure ?
mkh1099 OP
15 posts
 
Thanks for the help!
To answer your questions, I don’t know the frequency range of my meter. But it was inexpensive.

and the maggies are about 9 ft away..
        and thanks, MC! It explains a lot knowing that was logarithmic
tomic601's avatar
tomic601
12,866 posts
 
so the amp is loafing at 75db 9’ away at listening position. You should try to improve the noise in room IF possible. I have a 20 db fan outlet that is clearly audible. You should also try to demo a lower power amp, consult to Maggie crowd..

@bdp24 will have excellent advice, he can hear and knows tge value of an spl meter..
don_c55
1,025 posts
 
An ambient noise level of 40 dB is very high!

My ambient noise level is 28 to 33 dB.

My Magnepan 3.6 "wakes up" at at around SPL peaks of about 75 dB.

But that depends on amplifier quality, 

A very high quality power amp can sound very good, late at night, when ambient noise is low, even at low volumes.

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