Danley doesn't rate their subs with 1W 1M. They use 2.83V. Which for an 8 ohm cabinet is essentially 1W/1M. But for a 4ohm cabinet it's more like 2W/1M. So a TH-118 would have to be derated by 3dB to compare "spec for spec" to other 4 ohm subs.... Which isn't the best practice anyway. Your best bet is to do exactly what you did, and listen for yourself.

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If you want to "play a little game", take a look at the Th118 spec sheet.

http://www.danleysoundlabs.com/danley/wp-content/uploads/2012/04/TH-118-spec-sheet2.pdfLook at 93ish Hz. see that impedance peak? Now look at the amplitude at that freq.

The sensitivity is around 109dB with the 2.83V input. Which is less than 1 watt at that freq. So figuring the impedance is around 9.2 ohms-the voltage required to get 1 watt is a little over 3 volts. The difference between that voltage and 2.83V (the applied voltage) is around 0.6dB.

So using the "1 watt" method-the cabinet produces around 109.6dB with 1 watt (at one freq) below 100hz.

So the cabinet "could" be rated at 109.6dB below 100Z 1W/1M and still not be lying.

AND WHILE WE ARE AT IT-what does the 1M really mean?

Danley does not measure the subs at 1M. If we did, then the ACTUAL MEASUREMENT would be HIGHER.

We measure subs at 10M (a 20dB loss in distance) and drive at 28.3V (a 20dB increase in level) so they cancel each other out.

So this brings us to the REAL reason for specs. What is that?

In my opinion, it should be used so that an sound designer can get an idea of what a particular product will perform like at some distance (NOT 1M) away from the cabinet.

If Danley were to use the actual SPL measured at 1M, then at say 20M away the SPL somebody would measure would be LESS than the calculated SPL-using the 1M spec.

But by using the 10M measurement-and "back calculating" you end up with a number (all be it lower than what it actually measures at 1M) that WILL calculate out to longer distances-so the number presented is actually USABLE and not some "inflated number" that looks good on a spec sheet.

Now this works the opposite way as well.

Take the Danley SH25. If you were to actually measure it at 1M, you would read LESS than the rated sensitivity by almost 6dB.

So is this number false? NO. The number is used to figure out how loud the cabinet will be at a longer distance-and it is measured a distance away and again, back calculated to 1M

So why is the measured number lower? It is because of the depth of the horn.

In the SH25 the acoustic origin is physically almost 1M behind the grill. So it has undergone a good bit of "expansion" before it even gets to the grill-so the mic is actually close to 2M away from the acoustic origin or source.

But if you use the rated sensitivity and figure out the SPL at say 20M-the number you would measure is the same as the calculated.

Once again-it is IMPORTANT to understand what the numbers actually mean and where they come from-how they are determined etc.

The numbers should translate into the REAL WORLD in a way that is useful to a designer.

If not-then they are pretty much useless.

PS I know that some other manufacturers use the same methods-but not all. Hence the reason to know where the numbers come from.

Are they on the spec sheet to look good-or to actually MEAN something useful?

That is often a tough question. Who put them there-the engineering team or the marketing team?