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For you guys with SPL meters or concerns about bass...


Mallette

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Below are the Fletcher-Munson curves with the standard weightings below that.

This is neither trivial nor a technical irrelevance. Those of you who listen at much below "realistic" levels simply will never hear bass like at realistic levels without intervention. In order to do this, you'd have to set EQ curves for each listening level. While, IMOH, this is best done by ear, you need to use an SPL meter to determine what levels you generally prefer if you wish to get the EQ "in the neighborhood" before fine tuning. Also note that "C" weighting is quite different can produce up to a 10db error compared to human perception at realistic levels. The "A" weighting is closest to and designed to emulate human perception in the normal range. Those with vintage systems having variable loudness contours may get some satisfaction from them, depending on the type of loudspeaker they were designed for. Remember, it's the speakers response that needs altering, and different types of speakers need different alterations to achieve apparently flat response sound at a given level. That is why some folks feel their loudness circuits work well, others feel they don't. Certainly only a continuously variable loudness compensation circuit has much chance of being effective at any more than one level.

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My DBX 14/10 Eq can do this automatically (RTA/SPL) and it can be stored for recall in 10 different listening positions with the push of a button and little sliding of the pink noise level control. SPL can be measured in real time and by frequency not just overall. You can even average the 10 memories together if you like. Hard to rely on your ears, especially mine. Incredible unit with incredible control, and despite what people think NOISE FREE!

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How true Dave! Thats why when I do live-in-concert recording, I take a SPL meter with me. So I know for sure what level the original performance was at on various parts. That way, when I get back to the studio for mastering, I'm reasonably sure that I'm in the ballpark, sound balance wise, on playback & can make any adjustments accordingly, if necessary.

By the way.....I don't see any curves.

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Thanks for fixing the pix. I now know "what" but not "why." I checked properties on your image and mine, and found mine is indicating my own drive, while yours is resident on the forum drive.

I used the rich text editor's "upload" function to send it up. I'll know what to check next time...but am not sure what to do about it.

Dave

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To be clear- Fletcher-Munson curves don't really have anything to with speakers, but have everything to do with our ears. They depict our hearing system's non-linear sensitivity. We are much more sensitive to midrange frequencies at low levels than high and low frequencies at those levels, regardless of the speakers. At higher SPLs our sensitivity is more linear (frequency-wise). I'm sure many of you in this thread DID know this, but for the confused lurking out there, I thought pointing it out might be helpful. Incidently, it's my opinion that these peculiarities are evolutionarily designed. It benefited our survival rates to have this varied sensitivity. The most sensitive range of our auditory response is that of frequencies related to speech and critters moving around in the woods, enabling us to more easily communicate and hunt.............but I digress 1.gif

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Trey, I use Klipsch Promedia 2.1's on the computer I do the editing/mastering on. I also use AKG K270Studio headphones. After that, I burn a test CD & listen to it on the main system in my studio/music room. If all is well, I'll then test play it on the rest of the more typical stuff, the care stereo's, another CD player on the video's audio system, etc.

I honestly don't know if the Promedia's could be considered near field monitors or not. Most of the music I have to edit/master doesn't have much in the way of deep bass. The grand piano is about as low as I need to go. But they're just fine for me, especially since I can always fall back on the reference system downstairs.

As a side note, The AKG K279 Studio headphones are really quite remarkable. I use them for monitoring the recording during the live concert. One time, after I had the mix balanced out, I handed them over to my wife for a listen. After a few seconds she takes them off & hands them back to me & says she cant hear anything. I put them back on, & their on alright. I give them back to my wife & she puts them back. I turn the gain all the way off. The expression of surprise & her mouth drops wide open. She couldnt believe that she couldnt tell the difference between the live sound & that which was coming from the headphones, even as they were being put on or taken off!

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I have a reference to a Dec 1997 JASA, Vol 6, page 3644 for curve fits to the original 1933 data. Not sure whether this is Audio Society or Acoustics Society. Does any one have online access to these Journals and can check. I have not had time to get to the library yet.

Jim N

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