Twl: I've heard Lowther's, but not to any great extent. I've also read the entire article that Nelson published. I've seen the response curves and have at least a decent idea of what it took to get that driver to do what it is doing. I can pretty much guarantee that there's nobody other than Nelson Pass in the entire world that is getting that type of response out of those drivers. That is, unless there's someone else out there using similar equalization circuitry and an amp that has an output impedance that is appr EIGHTY ohms.
Even with all of that and a horn mouth that is 5 feet wide and 6 feet tall connected to a cabinet body that is 9.75' tall and 4.5' deep, the speaker is still -3 dB down at appr 48 or 49 Hz. In Nelson's own words "I have been extremely pleased with the results, but i must smile when i see that all of this effort barely gets us below 50 Hz".
Other than that, i have 104 dB horns and have driven them with as much as 400 wpc SS and 35+ wpc tube. Two watts isn't enough power for a speaker, even at that efficiency level. That's because 104 dB's @ 1 meter becomes appr 95 dB's at a 10' listening distance. While this is pretty loud for most people, it is nowhere near the levels that one hears at a live orchestral performance if sitting reasonably close to the performers. This is not to mention a live jazz, blues or rock show either.
Besides the spl levels, with only 2 watts, one is pretty much guaranteed to run the amp into compression and clipping on a regular basis. On top of that, feeding that much steady state power into an excursion limited Lowther is going to create dynamic compression and introduce other forms of distortion into the equation. This is why, even though he had a GIANT horn doing all the work and keeping the driver properly damped and loaded at low frequencies, Nelson Pass stated "Still, they play loud cleanly in a manner that Lowther owners don't usually encounter, and the cones are barely moving". Without the aid of a horn this size, there is just no way that the Lowther can produce ANY type of bass and / or high spl at the same time.
As a side note, Nelson provided the readings as taken from a Lowther in a standard sealed box. Using the output at 1 KHz as a reference point ( industry standard ), this driver is down appr -15 dB's at 100 Hz. By the time we get to 40 Hz, we are down almost -30 dB's. That's why he couldn't squeeze ANY deep bass out of the driver, even in that phenomenally LONG and HUGE horn.
Needless to say, i DO like some of the advantages of a single driver, but i also realize that, at least at this point in time, none of them do everything well. If you want extension, you give up efficiency. If you want efficiency, you give up extension. They are all a trade-off, some to a greater extent than another. Sean
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