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?
It was SO loud I could hear it in MY house! Turn it down, please ...

91-92db SPL is the peak level you listened to unless you had the meter set to "average" in which case this was the average peak level (and actual peaks may have been higher).

Rock concert levels typically run up to 105 db SPL average (although this will be average for some songs and not others...a good rock concert will always have a variety of dynamic range in the music, as consistantly high SPL's eventually lose their excitement and become is all about contrast or dynamic range...many artists will do a little "unplugged" stuff in the middle of the show for example).

An unamplified piano can go to 110 db SPL. Enjoy!
The + or – 10 db indicates the range that the meter is reading. For example if the meter was set at 90 it would read from 80db to 100db. That’s why you got the same reading of 91 – 92 db whether the meter was set at 90 or 100. So it sounds like you were listening at 91 – 92db. The only thing you did not mention was whether you had the MAX button set, which would indicate that the meter was only displaying the loudest measured sound level during the sampling period.
I think it was set to AVG. I know it was fluctuating up and down, either at the.2 sec or .5 second intervals.

Is there a function setting to measure this particular aspect with?

Also, how can one find out about the diffs indicated in the literature as to the actual eff of the meter, as Ive heard more than one say "Accurate within 10%"... or did that only apply to the analog meters?
The digital radio shack meter is not a precision instrument. I don't think you can trust the absolute "accuracy" of readings to more than +/- 3 db SPL between roughly 50 HZ and 5 Khz. I read somewhere that the 10 db errors you talk about are at extremes of 20 Khz or at 20 Hz.
I seriously doubt that your meter is off by 10%. At the frequency extremes this would be believable, but at avg. listening levels, what the meter said was likely very close to what you were hearing.

Btw, I too find SPLs in excess of about 90db at the listening level to be way too loud. Peaks of 90-95 are about as high as I can tolerate. Even then, only for a particularly favorite song.
I know that when I was setting up my Velodyne SMS-1, and was supposed to get an 82-83 dB level, it was quite a bit louder than I usually listen.
dont forget the fast/slow switch-it should be on fast for "best" peak decibel readings.

thanks... I don't think the max thingy was in use.

db? I meant %. I may have misheard the reading of the info too, though I really thought the manual said +/- 10% accuracy.... at what range (if any was specified) I don't recall. the concern was that 10%. 10% of a 90db reading is 9db. that is pretty big if you ask me.

Thanks. I tend to agree. the issue for me is I have no previous refference. Any reading came as a suprize to me. though I felt the 91-92 (fast) readings preety fair an assessment... yet again... had no previous ref.

What I find amazing, or better yet, most interesting, about the SPL readings of ambient noise/sound at the LP, is the type or fashion of the sound being realized at the ears. Volume was surely in abundance, yet the striking, impacting or visceral dynamics were still not agregious.

The best I can describe it is the diffs from a plannar speaker to one using cones. these were cones too, though with limited responnse pressure levels... agan, 85db or so.

At no time was the sound near approaching "piercing".

Other speakers I've owned with greater Eff #s have had that "piercing" trait however. So there is IMO more to SPL than simply SPL. In fact I could well stand a touch more of a striking quality, but only just, to add to the dimensionality of the sound as well. The "jump" factor as I call it was lacking.

"A dollup or two more jump, if you please, my good man."... and I am a happy camper.

i know what you mean. it is suprizing, huh?

Makes me really wonder about speakers PROFESSING OR providing 100+db SPLs.

Who can handle that? Unless only a watt or two is used.

OK, So is there a better, or easier way using a PC to gain greater accuracy, and ease, in redeeming acoustic numbers, like SPL, nodes, nulls, spikes, etc?

....without a big expense being necessary?

Using the Windows XP Pro PC & monitor would be a very good thing for me. I'd not need any assistance.
Makes me really wonder about speakers PROFESSING OR providing 100+db SPLs.

Who can handle that? Unless only a watt or two is used.


My speakers "profess" to handle up to around 115 db SPL average continuous level with head room of around 10 db at 1 meter. This is with distortion levels extremely low (around 1% or so) and only modest compression.

Of course I never listen this loud.

At 2.5 meters back I sometimes listen up to about 105 - 108 db SPL (AVERAGE level - confirmed with Radioshack Meter) which is equivalent to attending a rock concert. This is loud.

However, to put things in perspective, at the hockey game last night the SPL meter in the crowd showed 115 db SPL - yet nobody was covering their ears and complaining that this was piercingly loud.

What actually sounds piercing and awful to the ears is DISTORTION - even at modest SPL levels!

Modest amounts of distortion will sound terribly loud at 90 db SPL (distortion levels are inherently linked to perceived "piercing" loudness)

What you might have experienced was increasing distortion at high SPL's (for your system) making it sound extremely loud when you only had a maximum of 91 db SPL at the listening position.
10% of a 90db reading is 9db. that is pretty big if you ask me.


If the accuracy is +/-10% then this is equivalent to +/- 1 db SPL at 90 db SPL.

Decibels are a logarithmic representation of a signal.
SPL = 20 Log (Actual Signal Reading/Reference Signal Reading)

Reference signal level was set by Bell Labs as the quietest sound the average person can detect at 1 Khz (defines 0 db SPL)

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)

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.

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).
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.