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using the Radio shack SPL meter

I got a digital Rad Shak SPL meter the other day. I'm trying to figure out just how to use it. At this point all I want to do is find out how loud is loud, for me.

I got it set to the C weighted setting. Set the Range to 80db, and then on to 90db.

Pointed it straight ahead fixing it at the listening position where my head would be and turned up the music. Slowly..Stopping now and then.

At a level surely loud enough for me, and off 85-86db speakers, the highest number shown on the meter was 91-92db.

Given the +/- 10% variation the gizmo is professed to have, does this mean I was listening to 91-92db, or 100-101db? Or 82-83db?

While on the 100 range the numbers remained the same with 91-92db still the highest numbers reflected on the screen at the loudest level I could stand, without worry of gear issues or for just brief periods like a single song or at best two. They’d need be short ones as well.

I've done nothing else. In fact whatever those numbers actually represent, it was certainly too loud for extended listening. IMO. I didn’t turn it up past that level either... though it may have produced greater numbers. From repairs or on the meter.

Checking the vol knob later I had some more room to go but not safely as I was about the 1-2 o’clock position on the preamp.

I heard no audible clipping or distortion at any time.

How loud was I listening?
blindjim
shadorne's avatar
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shadorne
7,477 posts
 
Jim,

Here is an example.

Take a classic famous well respected "hall of fame" type speaker like the Wilson Watt Puppy 7.

Look at the two distortion plots at 90 db SPL and at 95 db SPL (top curve is output SPL and bottom curve is THD+N SPL)

Notice that as the sound level is raised by 5 db SPL the distortion components increase by much more (8 or 9 db SPL)....this is always the case, even on great speakers such as this. The higher the output levels (towards realistic live sound) the relatively greater distortion ...until eventually the distortion becomes audible (and perceptively very loud). This point will vary for each system of amplifier and speaker but generally even small systems can be made to be perceived as sounding very loud (but in a small system it is mostly the harshness of distortion and not ACTUAL SPL level that gives the impression of loudness)
blindjim OP
3,092 posts
 
Shadorne

Gee thanks. My heads swimmin' now from all the input you've mustered here. ...and I was once a whiz at math. Thanks much.

The distortion aspect you put forth is likely on the beam. that system was simply put at best, sterile and analytical. Nothing by way of cabling, isoing, conditioning, decent front end . . . just some cheap CD player, a Krell amp and my rusty, dusty Sony receiver as preamp. All in a much smaller room too.

That sound is not one I have today, nor do I want any part of it again. A touch more jump perhaps, but that's about it.
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shadorne
7,477 posts
 
Jim,

That sound is not one I have today, nor do I want any part of it again.

Glad to hear it. Unlike yourself, there are many who still suffer and remain unaware of how systems degrade rapidly when pushed to more challenging volume levels.

A touch more jump perhaps, but that's about it.

Sorry I can't help you with a dollop or two of more jump (unless you can be a bit more specific).
blindjim OP
3,092 posts
 
Thanks. I'm on it.

I'll be taking care of that in the future at some point. I suspect a couple tubes here or there, and some more eff speakers will do the trick. My current ones sound so akin to di poles and plannars it is astounding. Real nice for background or when you're working.

Things will work out. They always do.
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