test disk for plotting spl at a given freq?

ncstatesman

I have an Autosound 102 test CD that has sine wave test signals that start at 10Hz and go on up to 90Hz . . . .I want to plot my SPL for the sub 80Hz area of my system.

Can someone tell me if its ok to use these sinewave test signals at reference level (o dB on my rcvr) without damaging my subs?

Or, can someone recommend a better test signal CD to use? I plan to do this once I get my new 800i's (next week) - I'll use AVIA to calibrate my system to 85dB (0 dB) with my sats and 800i's set to SMALL.

Thanks!

scottvamp

I want to plot my SPL for the sub 80Hz area of my system.

I'm confused, are you trying to set your sub at 80db --maybe.

ncstatesman

actually, I want to use my SPL meter to plot the low freq response curve of my 2 subs. starting at 20HZ on up to 80Hz in 5 hz increments, then use an eq to smooth out the peaks/valleys in my sub's response -

lax01

Wow you are over my head, but all I gotta say is running a sub at that low of a frequency, that loud will (1) hurt your ears a lot (really use protection), (2) you might damage your subs. What type of subs are they? What kind of receiver are you using?

BTW, I Hate TRIG (from Honors Pre-Calc class), it scares me

Steve@3dai

I don't think you want to run the reciever at 0db.

What I would do is use pink noise, as it's equal energy over all frequencies (every octave up is -6db)

Then set your reciever to listening volumes and start with that.

Sometimes a flat response is not always what sounds best though!

- Steve

Stan Nuremburg

Sine waves are NOT good for evaluating subwoofers - they will overload the sub, and set up standing waves in the room itself.

I suggest either pink noise, or "warble tones." Audio Control was (is?) a manufacturer of VERY user-friendly graphic equalizers in the late 70s thru the early 90s, and one of their units, called the Richter Scale (most recently, Richter Scale III or similar), came with a warble tone generator and calibration mike, etc.

However, Tracks 20-31 on the the first Stereophile test CD (sn # STPH-002-2) contain a 1kHz 1/3 octive warble tone at -20 dB followed by a series of 1/3 octave warble tones at 200 Hz, 160Hz, 125 Hz, etc., down to 20 Hz. This might be a good tool for sub adjustment, eq, etc.

Calibration devices are not necessarily highly accurate in the low bass, hearing is not as sensitive to low level, low frequency sounds, and the room itself will alter low frequency response, so I agree with the person who reminded you that you should remember to trust your ears. Measured flat does not always sound best, so if your system measures flat, don't be reluctant to adjust it further if it sounds better that way. Hsu Research and other manufacturers have lists of good recordings for evaluating bass by ear. Good luck and good listening.

20hz

I use a stryke disc it does 20-20khz plus all the test tones you could ever use .
I use it for testing speaker response I use a db meter and draw a graph w/it

FestYboy

15 years later...

wow.