In my case, I am running a tri-amped 3-way system, where the tweeters are driven by one amp, the midranges are driven by another, and the woofers are driven by the third amp. Here is the info for each of the drivers in my system:
I, too, am running tri-amped but in a completely different way:
One stereo NAD 2200 amp for the pair of Dahlquist M-905 mains 8" ported woofer & tweeter.
And one PROTON D1200 amp for each of the DYI 12" dual 4 ohm voice coil (configured to operate as if a singe 4 ohm load) floor firing (speaker and port [FR 20-80 Hz).
First a bit about the M-905's (and then about their amp):
The nominal system impedance is 8 ohms (6 ohms minimum), and the M-905 is recommended for use with amplifiers rated to deliver from
20 to 125 watts per channel.
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 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 black 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.
Actual measurements:
There is a very small bass-resonance peak. At the system resonance of 60 Hz, the output is only about 2 dB above its average level in the upper part of the woofer’s range, (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.
Minimum impedance is about 4.8 ohms in the 8,000-10,000-Hz region, and it measured 7 ohms at 150 to 200 Hz. The maximum impedance was 28 ohms at 60 Hz, and there was a broad peak of 18 ohms in the vicinity of 1,500 Hz.
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.
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.
IMPORTANT to
@Dave TR3A:
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.
The NAD 2200 AMP DYNO TEST:
The DYI subs have a HP of 55Hz and a LP of 70 Hz & each one gets its own PROTON D1200 amp running at 4 OHMs bridged mono. And are rated to handle over 2000 watts EA.
Here is a PROTON D1200 on the AMP DYNO:
As you can see, there is a large discrepancy between what the speaker designer suggests for power and what the speaker can actually handle.
But, you, as the operator, must use discretion.
docs.minidsp.com
