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Audio Test CD for running Frequency/SPL charts, etc.
http://diyaudioprojects.com/Forum/viewtopic.php?f=5&t=95
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Author:  RiGuy [ 03 Aug 2008, 23:53 ]
Post subject:  Audio Test CD for running Frequency/SPL charts, etc.

PLEASE BE CAREFUL. Some of the tracks on the BinkCD are specifically designed to destroy your speaker. Why? I dunno. Read the word doc about the BINK CD and it will tell you which tracks do what and why. Great CD but maybe you like your speakers functional.

So you want to graph your Frequency/SPL for your speaker? All you need is an spl meter, a tape measure, pencil and paper, some way to make sure you are putting out one watt exactly ( a digital multimeter), and an audio test cd.
Here is a link to a test cd page.
http://binkster.net/extras.shtml
Here is the link straight to the cd file http://www.4horsemen.net/binkster/full_cd.zip
and here is a link to a short word doc on how to use it.
http://binkster.net/UsingTheBinkAudioTestCD.doc

Found another CD here http://virtuelvis.com/archives/2004/09/audio-test-cd
Gives some instructions on speaker placement as well.

Or how about this one from Alan Parsons. A double CD with the Sound pressure meter BUILT IN to the CD case!!
http://secure.keyfax.com/Merchant2/merc ... cellaneous
Ri

Author:  Gio [ 04 Aug 2008, 09:13 ]
Post subject:  Re: Audio Test CD for running Frequency / SPL charts

Thanks for the nice summary Ri. I have been using the test CD from virtuelvis, but this binkster one looks better. I use a Radio Shack 33-250 SPL meter. It works good, but you do need to correct some of the reading.

What SPL meter are you using?

Author:  RiGuy [ 04 Aug 2008, 09:46 ]
Post subject:  Re: Audio Test CD for running Frequency/SPL charts, etc.

I want one but I dont have one. Its hard to justify $50 just to measure what is already there. Kind of like a scope. Wife wouldnt understand and right now its not a necessity. So, Anyway I just played the audio cd. Actually was sitting down to see what frequency I was listening to. I have to go to the guys site and get the TOC for the disc. Tracks 11-44 are frequencys and my Audio Nirvanas may have been producing track 44 but I couldnt hear anything. I could hear up to 43. They play all but 44. So as far as low end I get everything on the disc but at track 15 is when it really has authority in that tone. Tracks 11-14 play but is more like rushing air than a audio sound. When I cranked the volume a bit tracks 13 and 14 were more obviously there and 12 a bit but 11 is just the driver moving and pushing air but not me hearing much of anything. So I will be right back. I have to check what the frequency of those are...........................................................

Okay. Neat :) Looks like I can hear 16kHz. The ears are not failing me yet. I should go find some 17, 18, 19kHz. The driver is supposed to take a nosedive at 17kHz so I suppose that might not do me much good to try. Could test it on the Fostex I think though just to see what I can hear. Then we have
# 11 16Hz
#12 20Hz
#13 25Hz
#14 31.5Hz
#15 40Hz
So the driver in the Bass Reflex box is producing 40Hz with authority and it specs state that the Fs is 37Hz I think. Lemme check.... Nope, I am wrong. The Fs is 33.8Hz. Pretty believable from what I just heard and it tries to go lower. It actually plays the 25Hz. Hmm, maybe I need to read up on what Fs is. My definition may be different than reality. I wonder if the BR enclosure is helping it get lower than its Fs. Guess it depends on how they tested it.
So there you and there I have it. I am satisfied :) That was cool.
Ri

Author:  Gio [ 04 Aug 2008, 19:30 ]
Post subject:  Re: Audio Test CD for running Frequency/SPL charts, etc.

Yeah, I can hear to about 16.5 kHz. When you do measurements, it is surprising to see how non-linear our ears really are.

Author:  RiGuy [ 05 Aug 2008, 12:20 ]
Post subject:  Re: Audio Test CD for running Frequency/SPL charts, etc.

If you read this and downloaded BINK then please please read the word doc about the CD.... You can destroy your speakers on a few of the tracks since thats exactly what they are designed to do.

Author:  Gio [ 05 Aug 2008, 17:23 ]
Post subject:  Re: Audio Test CD for running Frequency/SPL charts, etc.

Yes, as with any test CD you will not want to have the volume up to high for the low frequency tracks.

Author:  RiGuy [ 05 Aug 2008, 18:56 ]
Post subject:  Re: Audio Test CD for running Frequency/SPL charts, etc.

True, but what I am referring to is these selections:
Tracks 54-55: Square Waves. Watch out for these tracks! Turn your amps off first! Square waves are sometimes used in destructive testing at audio R&D labs... Don't run them at high volumes if at all. The most vulnerable part of your system are the HF drivers which can fry with square waves! These tracks are useful in setting CD input trims. If your channel input doesn't distort from Track 55 (which slams in at 3 dB above digital ceiling!), it won't distort from nearly any commercially available CD out there. You can also listen for crosstalk on other channels -- it comes through most severely with square waves in neighboring channels. It is not ever necessary to send square waves out to amps and speakers in a normal live sound setup situation.

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