Yamaha NS-1000 Monitor Speakers - Excellent Condition
NS-1000 can be placed fairly close to the front wall without losing too much sense of depth and perspective - and they don't mind a bit of room-gain to compensate for the early low-end roll-off. NS1000 doesn't go particularly deep. At 50 Hz we're down some 3 dB. Due to the properties of the bass drivers and cabinet tuning we have some elevated response in the ~80-120 Hz region adding volume and warmth to the overall sound and I haven' done anything to change the performance here. An LCR impedance flattening circuit could easily change this (550 uF + 18 mH + 6R8 for those who want to experiment). Trying out two Variovents could be another area of experimentation, but deep bass we're never going to get. I wouldn't consider a vented cabinet for this bass driver although 80 litres and a vent tuning of e.g. 28 Hz does look better (-6 dB @ 30 Hz).
If we imagine sitting at the conference table at YAMAHA back then and setting the targets for a new 50 litre 3-way, there may have been arguments for using a 10" bass driver. We might even maintain system sensitivity with a 10" bass driver and we could easily get another 5-10 Hz bass extension. Two arguments may have prevailed: 1) JBL's got a 12" system out already with this size bass driver and 2) a 12" driver loads the room like no 10" does;
The crossover is designed to maintain the basic virtues of the old crossover, i.e. points of crossover have not been changed, neither the option of balancing mid and treble level to actual room acoustics, your system and personal taste, albeit not as much as the L-pads, but I guess no one is using these to the extremes. The improvements in sound comes from:
1/ Re-designing the bass driver's low-pass section
2/ Smoothing drivers' roll-off slopes.
3/ Substituting all electrolytics with state of the art super caps.
4/ Using better coils; thick-wire cored for bass and wax foil-coil for mid (using air cored coils for the bass does not improve performance).
The bass has a hard pressed paper cone with coated fabric surround. Good, because this will last for decades. Fs is around 20 Hz and Qt = 0.27 and we have a 50 litre closed box providing an F3 of 49 Hz. The cabinet is entirely filled with glass fibre to increase virtual volume. Closed box lovers will like what it does and I agree. Bass quality is good and appears fairly deep given the modest sized enclosure. Comparing the bass to my DTQWT there's some lack of punch and drama in upper bass/lower mid, but overall good for the size.
The mid has an exclusive 3.5" beryllium dome. Beryllium has recently been reintroduced by Focal, ScanSpeak and SEAS for dome tweeters, but I think this Yamaha is the one-and-only when it comes to mid-domes except for 4" compression driver diaphragms.
The tweeter has a 30 mm Beryllium dome and despite limited frequency extension - it drops rapidly above ~15 kHz - it blends very well with the middome and does what a tweeter dome should do. The low-end roll-off is somewhat ragged, but with the high point of crossover this is only a minor issue. It is claimed it goes way beyond 20 kHz but it certainly doesn't, and given the consistency between the two domes at hand, I don't think there's anything wrong with them.
The crossover is a fairly simple 2nd order (electrically) on all slopes mostly providing close to 4th order roll-offs. As we shall see later this doesn't work fully optimal for bass and tweeter and there are room for improvements.