Well those "handles" are all relative. LOL
But truthfully its a rare speaker that can go below 40 or 50 hz and deliver much SPL without tons of distortion.
The big fad today is little stand mounts with a single 5 or 6" woofer so a decent "sub" box with a 12" driver and amp is a tremendous help to get any music in the bottom octave.
No fad 5 or 6" woofers here (not a 12" either) but a pretty well integrated 8":
My Dahlquist M-905's (2 way speakers):
Dahlquist M-905
Measure 24 inches high, 13-1/2 inches wide, and 12-1/4 inches deep. (not much in the way of a Spousal Acceptance Factor aside from a very nice walnut veneer)
Each speaker weighs 35 pounds, and for optimum results they should be mounted on Dahlquist ST-9 stands (they are), which match the finish of the speakers and support them about 11 inches above the floor, with a backward tilt of 3.5 degrees for optimum coverage of the listening area. Like most free-standing speakers, the M-905 gives its best performance when it is placed at least a foot from the wall and angled slightly inward toward the listener.
The 8-inch woofer of the M-905 is a polyvinyl-acetate-laminated cone operating in a vented enclosure. The outlet of its tuned port is on the front panel of the speaker cabinet. At 2,500 Hz there is a crossover to a 1-inch soft-dome tweeter.
The rated frequency response is 40 to 24,000 Hz (no parameter's given).
The wall panels are of varying thickness, and there is special internal damping and bracing designed to suit the individual characteristics of the drivers in the system, all to minimize coloration of the sound by the box.
The front panel is coated with a 3M flocking material whose thousands of fibers are electrostatically aligned perpendicular to its surface during application. The flocking and the flush-mounting of the tweeter are said to minimize diffraction from front-panel discontinuities, preserving image focus.
Now for a few (SURPRISING) measurements (from: HiFi Classic):
The close-miked woofer (and port) response was also considerably flatter than we have measured from most speakers, with a very small bass-resonance peak. At the system resonance of 60 Hz, the output was only about 2 dB above its average level in the upper part of the woofer’s range, and even that minor output variation was spread over almost two octaves.
When the bass curve was spliced to the room-response measurement, the resulting composite frequency response was flat within about
±2 dB from 26 to 20,000 Hz.
The horizontal directivity of the tweeter was only discernible in the room measurement above 10,000 Hz.
We measured the sensitivity of the M-905 as 87 dB SPL.
The system’s minimum impedance was about 4.8 ohms in the 8,000- to 10,000-Hz region, and it measured 7 ohms at 150 to 200 Hz. Its maximum impedance was 28 ohms at 60 Hz, and there was a broad peak of 18 ohms in the vicinity of 1,500 Hz.
We measured the woofer’s distortion with a 4-volt drive level, corresponding to a 90-dB SPL at 1 meter.
The distortion was less than 1 percent from 100 Hz down to almost 60 Hz, the effective crossover to the port.
Below that crossover the distortion rose to 5 percent at 45 Hz and 9 percent at 35 Hz.
In high-power tests with single-cycle tone bursts, the woofer began to sound “hard” at about 350 watts into its 8.5-ohm impedance at 100 Hz.
At higher frequencies the amplifier clipped-
at outputs of 490 watts at 1.000 Hz and 1,380 watts at 10,000 Hz—before distortion became visible on the acoustic waveform.
Quasi-anechoic FFT measurements showed an overall group-delay variation of about 0.1 millisecond between 4,000 and 20,000 Hz and 0.5 MS. between 1,000 and 20.000 Hz, convincing evidence of the attention paid to the phase characteristics of the M-905.
The pair of 905's are powered by one NAD 2200.
So what are the crossovers on my custom (by me) two 12" dual 4 OHM voice coil (set to run as one 4 OHM load each) subs with their own bridged mono NAD 2200's?
At the moment, it's 60 HZ for the high pass and 80 HZ for the low pass.
This seems to work pretty well and I see no reason to change it.
One day (when I get some measuring gear), I'll see what the in room measurements are and perhaps get some gear to make some tweaks.
But, it currently sounds fine to me.
www.townshendaudio.com
www.madisoundspeakerstore.com
www.madisoundspeakerstore.com
