Nearfield Acoustics Pipedreams

I have a large Pipedreams system (was it called Reference 21?) with 2 'depth charge' subs per channel.  That's 8 18" drivers total for 60-85Hz. and below.  Simply incredible.    Bought them new from Craig Oxford, placed in large (roughly 35'X 20' with high ceilings) room, and driven the towers with 2 Lamm ML-1s and the subs with 2 Rowland Research (before they changed their name to 'Jeff Rowland Design Group') Model 7 monoblocks.  

A really amazing system.  I'd post a photo of them in the room, but not sure this forum allows that?  Don't see an obvious way to post photos.  

Might be selling them, so if anyone's interested (I and the speakers are in LA) let me know and we can talk about it.

The woofer in the Pipe Dreams have a resonance of around 180 Hz. So they roll off at 12 dB per octave from there since they are a closed box. The crossover is around 65 Hz so they are already way down in response and keep dropping. You should use one of the couple different crossover/equalizers all of the speakers came with. These provide the proper crossover and sensitivity balance to the towers and extend flat response for the system to about 16 Hz. Needless to say since the roll off is extreme the equalization needed is large. Use at least 500 watts. The only tube amps for the subs I'd use are the Melos monoblocks which put out over 400 watts triode. By the way Melos amps and Pipe Dreams speakers were designed by the same people.

The mid ranges and dome tweeters look like Audax drivers. They were assembled by Audax but they are very special drivers just for these speakers which can be a problem for replacing them. They are very low mass which is partly achieved by lightening parts like voice coils, etc. So there are no equivalent replacement drivers. The low mass relative to the magnet motor makes them very fast to start and stop.  But the individual mids and domes have fairly low power handling and were only designed to be used in large quantity as in the Pipe Dreams so the large number of them still gives huge total power handling produces the speed of low mass and still huge power handling and clean, super high output.

Setting them up in a large room is easy but they will dominate the romm. Use rule of thirds for the towers. The tweeters should be inside and the towers should be toed in so if you sit at the equilateral triangle position you just can't see the inside side of the tower. That time aligns the tweeters. The tweeter crossover is about 6 kHz at 6 dB per octave so the towers are linear phase. The seat at the triangle will give the best imaging. But imaging is excellent everywhere, even when the listener is outside of the speakers at the side of the room. They still image.

The woofers(use one or two per side, each module has 2 18" woofers). Place them symmetrically relative to the towers. Again use a crossover designed for the speakers. Some of them have a test tone at the 65 Hz crossover. There is a phase control on the crossover. Use the control to null out the 65 Hz tone. Then use another control to flip the phase 180 degrees and you get an awfully good integration of woofers and towers.

I would say that there is a real size differential in the sub diameter, versus the midrange diameters, surveyzop