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Why should anyone?
 

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DO a google search on Radio Shack correction chart.

Quote:
Why should anyone?
LOL.... we all "think" it and DMF says it.


:p
 

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that would be a HUGE chart!
 

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NismoZ,


Here is you correction numbers for the Radio Shack Meter..

Hope this helps. Sorry I Can't find it in 1Hz inc.


10Hz add 20dB

12Hz add 16.5dB

16Hz add 11.5dB

20Hz add 7.5dB

25Hz add 5dB

31.5Hz add 3dB

40Hz add 2.5dB

50Hz add 1.5dB

63Hz add 1.5dB

80Hz add 1.5dB

100Hz add 2dB

125Hz add .5dB
 

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Oh for gosh sakes!


It's because it's GENERALLY thought of as unneccary to take readings in 1Hz increments.


The RS correction values are posted on a sticky at the top of the sub forum. There is a pdf file for doing manual plotting and an Excel file for keying the values in. I'm pretty sure some finer increments can be found somewhere on Snapbug.com. as well.


DMF- you sooo bad! :D LMAO!
 

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I take it nobody here uses the realtraps.com test tones then? I, too, have wondered if 1hz correction increments were out there. But, I guess one can predict a given slope of points A and B and assume a linear path between them.


Still though, accuracy is accuracy after all.
 

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Quote:
I take it nobody here uses the realtraps.com test tones then?
There’s no real reason to do single Hz readings because equalizer filters are set up as octaves or fractions of octaves. Besides that, it makes no real sense, because single Hz means you’re taking half the number of samples with each descending octave – i.e, forty samples between 80 and 40 Hz, but only twenty between 40 and 20 Hz. Not sure how that can be seen as a legitimate pursuit of "accuracy."


Regards,

Wayne A. Pflughaupt
 

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Thanks Wayne - I stand corrected.


I just always thought it'd be the most accurate, given that realtraps.com even bothers with 1hz increments.
 

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It would be more useful if the number of samples remained consistent from one octave to the next. For instance, you would need half-Hz increments from 40- 20 Hz, and quarter-Hz increments below 20 Hz. Lacking that, you could do 2-Hz increments from 40-80 Hz; that would give twenty samples per octave from 20-80 Hz.


But “accuracy†can do more harm than good if you don’t use it right. For instance, a 1-Hz chart is going to give you a really rough response curve compared to a more generic 1/6-octave chart. This leads to two problems, IMO.


First, you will have a tendency to over-equalize, trying to smooth out every last ripple.


Second, many people find it difficult enough to study a 1/6-, 1/12- or 1/24-octave chart and figure out they need a 1/6-octave (or whatever) filter. Trying to divine filters from a 1-Hz chart will be a real challenge for everyone but the most experienced EQ nerds.


Regards,

Wayne A. Pflughaupt
 

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1hz increments often reveal problems hidden by 1/3 octave analysis.

For example, a 6db peak at 100hz in a 1/3 octave sweep, might actually be a molehill at the base of a 12db peak at 105hz.

If you are using parametric EQ to correct this problem, you might as well nail it!


I agree though, 1/3 octave analysis very quickly gives you the basic response trends necessary for finding optimal speaker and listener locations.


BTW, I have found that I can set up a subwoofer and crossover more satisfactorily using familiar music with lots of bass, vs objective methods (tones etc...)

The crux of the matter is not how close you can get to flat response; that ain't gonna happen without a dozen good bass traps; then maybe!


The issue is the impact of random peaks and valleys on the subjective tonal quality of bass instruments.

For example, a 20-200hz room response that looks reasonably flat(+/-6db) on a chart may sound totally wrong when applied to a big kettle drum, or too weak in a movie soundtrack with ominous subterranean bass vibes etc...

It's the art of finding the best sounding compromise.

Figuratively speaking, you are literally baking an audio cake.


BTW, most folks start down the road of room measurements etc... because the bass in their system is weak, or lacks punch, or isn't tight enough, or something to that effect.

Most of these complaints are caused by excessive room reverberation decay times at certain modal frequencies.

More than any other factor, this is the issue that good bass traps address.

Even if the response is not significantly flatter after installing the traps, the bass will still sound much cleaner and tighter.

It would be far better to spend $1500 on a sub and $500 on room treatments, than to spend the whole $2000 on a sub with no room treatments.
 
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