Originally Posted by Archaea
1/2 Touche is definately in order....and I give you full props for testing. My challenge pretty specifically said MLP, and while 1.5feet away may be MLP for some - it isn't for most, and wasn't the idea behind my statement.
However --- I'm very
impressed that even nearfield the FV15HP pair weren't violently port chuffing at 10hz and 115dB.
THANK YOU for testing!
To be honest...I wouldn't believe it either if I hadn't tested it myself.
One thing to keep in mind when measuring nearfield, it more closely resembles an anechoic response (think close mic testing) as you are essentially removing room gain from the equation. How much room gain is removed depends on the distance of mic to sub, proximity to boundaries, etc.
In large rooms with little room gain, you might expect that a neafield measurement might have the most output. However, in rooms like mine where there is a lot of gain, it's probably one of the worst positions to measure if you striving for max output in-room. Measuring further away from the subs would factor more room gain into the equation for rooms like mine.
I didn't test the farfield response at 10hz compared to my nearfield measurement, but I did test it at 15hz.
This response was from a 15hz sine wave with the mic nearfield (~3ft away from each sub), and the main volume at -25db or so. This produced a Max SPL of 96.6db.
This was the response of the same 15hz sine wave taken 10ft away from the pair of FV15HPs, at the same main volume as the 96.6db measurement above. This produced a Max SPL of 105.8db.
Given that the main volume did not change, and only the distance, the extra ~9db or so can be attributed to room gain. Also note how the distortion changes...no visible harmonic distortion on the frequency response.
If I were to perform the same test with the 10hz signal 10ft away, chances are I would get similar results...actually perhaps even more as there is an additional half octave to build more gain. Granted, I could have been in a room mode at 15hz in that position 10ft away, but regardless, I wouldn't be surprised if the output at 10hz is north of 115.8 10ft away. I'd also expect little to no distortion showing up on the response as well, similar to the 15hz test.
Originally Posted by rcohen
Was that door rattling when you did the measurement? Could that have thrown off the measurements?
Yes, the door was rattling as the 10hz sine wave was causing the room (and door) to pulse. It should not have had any impact on the measurements since the 10hz sine wave was at such a high output. I guess it's possible the door could have produced 10hz sound as it rattled (if that's what you're getting at)...but no where near a significant level to change the response or output.
Edited by dominguez1 - 12/23/13 at 7:29pm