Harbor Freight portable DC first impressions

[cgallery]

Bought one of these today:

http://www.harborfreight.com/cpi/cta...emnumber=94029

My very early first impression was, "boy, this thing is kinda loud." I pulled out my handy-dandy RS SPL meter and measured it at 88db/1meter. The Ridgid 1450 shop-vac I use measures 78db/1meter. So the HF DC is twice as loud as the shop-vac.

It does seem to be moving a lot of air. I have to pickup some adapters and hose tomorrow so I can do some Cheerio testing.

I was just stunned with the amount of noise it made. If anything I was expecting it to be quieter than the shop-vac. Must be a combination of the universal motor and gearing they use (if any) to reduce the RPM's.

[dramey]

3 db is twice as loud, 10 db is close to 10 times louder. The decible scale is logrithmic, not straight line.

[cgallery]

3 db is twice as loud, 10 db is close to 10 times louder. The decible scale is logrithmic, not straight line.

R U sure? Perhaps you're above-average.

Of course it's subjective. But it's a standard based on objective analysis of a number of subjective opinions. An average, so to speak. But the numbers used now are not subjective. And the average person will perceive an increase of 10dB (appr) as twice as loud.

From:
http://www.radiolocman.com/electrica....html?di=18861

[wbsettle]

It's takes twice the input power to produce 3db more output from a given speaker. If 1 watt produces 90db, 2 watts = 93db, 4 watts =96db, etc.

A 10db increase is perceived as twice as loud. The log scale just means 90db is twice as loud as 80db, not 45db.

-Brent