Frequency Response Of Speakers-Subwoofers

Did i started talking about the Frequency Response of the Marketing? Not really because the things will go far,but sometimes you have to go far.

Well,except Watts the manufactures are also faking the Frequency Response of there product,so you'll think a speaker will go lower.

A Frequency Response stated by a manufacturer will be trustable only if the manufacturer state how it's measured.



For example we have two Subwoofers.

The one says: 18hz-300hz (manufacturer states -12db or nothing).

The other one says: 45hz-300hz (-3db).

Which will go lower? Of course the other one... Or maybe both will be the same "low".

The 18hz which is stated by the manufacturer of the first will be:

1) The Frequency in which the Subwoofer will produce a signal with -12db loudness,so it wont be useable at that Frequency,with the useable Frequency Response being a lot higher,maybe close to the other that states 45hz with -3db (useable).

Or

2) The Frequency in which the Subwoofer will completely stop responding so that statement is completely useless.

Now the other one which states 45hz is trustable because the manufacturer states that goes to 45hz with only -3db.

When you see 0db or -3db measurements,it means that the stated Frequency can be produced.

The only problem is that a Speaker might be flat and useable from 100hz to 20khz,with an ability to play 50hz audible and useable,but nothing between 50hz and 100hz,so the manufacturer can state 50hz-20khz and trick the customer,that's why you should listen to the Speakers you want to get before you get them,and maybe check a Frequency Vs SPL graph if there's available.

Let's see an example:

The so called "Audiophile" Logitech states for the z-5500 a frequency response of 33hz-20khz but they don't say on how much decibels is measured... It's a top secret i guess... NOT!!!

Here's a Review of the Logitech z-5500 by Techlabs.by (Link)

If you scroll down you'll see a Frequency graph,it's not much trustable because it's Smoothed to 1/3 Octave so big jumpy lines and gaps are shown as "Flat" nice lines.

The 100hz are produced with approximate 138db or 139db,50hz with 135db,and bellow 50hz the SPL goes WHOLE 5-10db per 5-10hz!
*Note the SPL shown is not real,they probably used 135db as base instead of 0db probably because they measured with a Microphone that isn't calibrated to measure SPL.

So... Do you see any USEABLE 33hz there,as Logitech stated? NOOOOT! Bellow 50hz,all i see is deadly silence.

Why not? Because they didn't said "Useable" and they didn't even mentioned the -/+ Decibels of that measurement,they just stated a crazy impossible Frequency Response for Marketing reasons,like many companies of course.

My advice is to always trust your ears and your own Tests,and not what they say unless there's evidences like trustable Frequency Graphs.

Also,the Low End Frequency Response is nothing,you're placing the Right Horse for the Right Course,your bright desires of having 1hz might not be that bright if your room says no,YOU WILL Stick with your 150hz and YOU WILL Forget about 10hz if anything bellow that will be unuseable and cause you more problems!

Do not forget to also read this article: http://www.theaudioignorance.info/2010/09/low-frequencies-cant-be-heard.html