Sorry for the double post, but something else I just thought of. Do TH118s not gain 6db when you double the number of cabinets? Looking only at the continuous numbers and assuming the TH118 does gain 6db when doubling, it should really only take 2 TH118s to equal one BC218 in continuous ouput.

Here is a good example of where simply looking at the "simple numbers" can get you in trouble.

To get the real answers you HAVE to look at a calibrated measured response.

The "continuous outputs" are based on sensitivity specs and power capacity and impedance.

But what is the sensitivity number based on? For Danley-it is simply a number that I choose (not somebody in the marketing department) that I feel represents the overall average sensitivity.

But I could very easily choose a higher sensitivity and it could still be correct-because the speaker is able to produce that SPL at some freq.

HOWEVER-AND THIS IS A REALLY BIG BIG DEAL-that many manufacturers simply choose to IGNORE.

What does the -3dB or -10dB number come from?

It HAS to be -3 or -10 from "something"!!!!!!!!!!!!!!!!!!!!

The ONLY way it makes ANY sense is to have it TIED to the sensitivity number. Therefore it is simply the freq at which the level is 3 (or10) dB down from the sensitivity.

OTHERWISE it is simply a number that (usually the marketing dept) thinks would look good on a spec sheet.

So what does this mean? If we wanted a higher sensitivity number-then we ALSO MUST accept a higher -3dB number. If we want a lower -3dB number-then we MUST ALSO accept a lower sensitivity number.

NO WAY AROUND IT-At least and being honest and providing numbers that actually MEAN something.

That is EXACTLY why we provide the ACTUAL MEASURED response graph for the user to come up with their own number.

Without that- you simply have NO IDEA where the numbers come from.

And if you don't believe me- go look at a variety of spec sheets (trust me I do it all the time) and "double check" the "simple numbers (sensitivity and -3dB freq) and see how they compare to the curve that they provide-ASSUMING they provide a curve. It is become popular to not provide response curves-that way you don't have to "justify" your numbers".

There are MANY MANY manufacturers whos simple numbers simply DO NOT match their own response curves.

Our numbers come DIRECTLY from the response curve.

What does all this have to do with the original question?

Well it simply means that you cannot always easily compare the simple numbers when trying to determine how loud something will get.

It will vary with freq.

So once again- a "simple number" will often give a wrong answer.

I hope that helps a little in understanding how we get our numbers and what to look for when looking at other spec sheets.

DO NOT just look at the simple numbers-you can EASILY be fooled-and many people COUNT on that

Experience and real world is the REAL way to get the answers needed.

Go out and actually measure the products and see if they do what they say they do. Put them side by side other products of "equal" specs and see how they stand up. Not just in terms of SPL, but also sound quality-distortion etc.

I am not saying that others are lying-but in many cases they are NOT telling you the truth-at least in the way you are looking for.

Yes some manufacturers are much better and more accurate than others-but it is amazing to me how many can't even get their own spec sheets and data to agree with itself.

And this is not just at the "bottom" level-but also at the "top of the food chain" products.

But hey-if they can get you to buy a product based on the spec-then the marketing dept has done their job (even if they lied doing it).

That is also the reason that some companies will not allow "official" side by side demos. YES it happens-and fairly often. Are they trying to hide something?

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