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[dave celko]

Trying to understand what this information really represents.  Do the power values actually represent an equivalent voltage at some nominal impedance and if not, how were they determined?  Are the results with the speakers on the floor in some room, half space results outdoors or anechoic whole space measurements?  Are these actually 1m results or are they far field measurements calculated back to 1m?  Was the mic response factored in and how were the SPL values calibrated?  You may not know all of this information but it can be relevant to intepreting what is actually being presented.

if i recall correctly these are taken at actual power figures( measured voltage) half space results outdoors with a calibrated mic at 1 meter

i could be wrong though these may have been indoors 1 meter results,im pretty sure it was done outdoors though, i would have to ask the designer to be sure

[Ivan Beaver]

if i recall correctly these are taken at actual power figures( measured voltage) half space results outdoors with a calibrated mic at 1 meter

i could be wrong though these may have been indoors 1 meter results,im pretty sure it was done outdoors though, i would have to ask the designer to be sure

I see the term "calibrated mic" thrown around quite a bit in various forums-yet the people using the term have no idea what it means.

Sometimes it means a calibration curve or "correction curve" that is used  (if used) to achieve a flat response.

But then they just stick the mic into a measurement system-and the mic remains uncalibrated to the system-so while the response may be "corrected", the amplitude can be tens of decibels off.  The system has no idea what mic is hooked to it-what the output level is and so forth.

Unless a PHYSICAL calibrator is used each time the mic is hooked up-then the SPL numbers really don't mean anything or can't be trusted.

I have no idea on the case in question-just saying it is something that needs to be considered.

Just something to consider.

[Brad Weber]

if i recall correctly these are taken at actual power figures( measured voltage) half space results outdoors with a calibrated mic at 1 meter

i could be wrong though these may have been indoors 1 meter results,im pretty sure it was done outdoors though, i would have to ask the designer to be sure

Thanks for responding.
 
The impedance of a speaker varies with frequency thus the power delivered with a given input voltage also varies.  I would guess that those aren't really 1W, 10W, 100W, etc. curves but probably more like 2.83V, 8.94V, 28.28V and so on.  It may seem like a detail but if the responses shown actually represent 1W, 10W, 100W, etc. into the speaker for each frequency measured then that is showing something very different than a typical frequency response graph that reflects a defined voltage at all frequencies.
 
If the measurements are ground plane at 1m then that close to the speaker you could get different contributions of the casing/enclosure radiated, horn and direct driver components of the sound than you would at some distance further away.  If those reponse curves are at 1m then I wonder how they might differ if measured at some distance away and referenced back to 1m.  For example, would some of the higher frequency raggedness be less noticeable?

[dave celko]

Thanks for responding.
 
The impedance of a speaker varies with frequency thus the power delivered with a given input voltage also varies.  I would guess that those aren't really 1W, 10W, 100W, etc. curves but probably more like 2.83V, 8.94V, 28.28V and so on.  It may seem like a detail but if the responses shown actually represent 1W, 10W, 100W, etc. into the speaker for each frequency measured then that is showing something very different than a typical frequency response graph that reflects a defined voltage at all frequencies.
 
If the measurements are ground plane at 1m then that close to the speaker you could get different contributions of the casing/enclosure radiated, horn and direct driver components of the sound than you would at some distance further away.  If those reponse curves are at 1m then I wonder how they might differ if measured at some distance away and referenced back to 1m.  For example, would some of the higher frequency raggedness be less noticeable?

i belive what he did was set power using the speakers impedance 8ohms, and then play the frequency sweep.he uses REW for measurments
its the same system i used to take that in truck measurement of a single cab for somone who wanted to see how it would work inside a car/truck as an car audio sub box

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