FR from sitting position. Octave and 1/3 octave smoothing. Still thinking of ways to integrate the sub better in terms of FR. The blending of the subs and mains is almost seamless though, something I don't want to give up. Hi-Fi is not simply flat FR, there are many other un-measureable aspects to take into consideration. Otherwise I would have stuck with my low efficiency extremely accurate active crossover system of yesteryear.

The ~10db downward slope from 20Hz to 20kHz is appropriate for measurements taken at the listening position. It would sound bright if the line were flat at the listening position. Right now, I think it's a little warm sounding. Maybe a broad 0.5 to 1db push down at 200Hz would do the trick.

I'm having a hard time integrating the tweeters. Again not necessary a matter of FR, but rather of seamless blending. I suspect the cheap Bennic caps are imparting some coloration. At least that's what I hope. I am worried that a horn tweeter just won't jive with a paper cone; but heck Fostex does recommend these T90 tweets with their drivers. Maybe I need the special Fostex caps.

BTW digital PEQ is applied in JRiver. There's no reason not to use it.

The Hsu sub is integrated REL style. The secret to REL's blending is found in their instruction manual. REL sees the sub there more to augment existing speakers' at the low end and gradually blend things in. I had an older 12" VTF series sub from Hsu (and a REL Stadium series), but I could never blend that VTF sub in properly. The Hsu 10" STF-2, which I picked up for cheap, seems to fair better than the VTF.

Here is the setup / config:

• The speakers play full range. Absolutely no x-over here to mess things up.
• Behringer DCX2496 is used as the DSP for the subwoofer.
• X-over using LR 12db slope at a low 30Hz.
• Time delay of 0.80m. (Back from driver to mouth of horn is approximately 66in. Distance from sub to mouth of horn is 34in. 66-34 = 32in = 812m) I need to run step response measurement to make sure it's right, but I feel this approximately measurement is good enough. Without the time delay, we can hear the sub kicks in earlier than the mains.

 Marv, for 30inch of separation, isn't the delay more like 2ms?

True, always felt that my current speakers have no dynamics at low volumes. It would be interesting indeed to hear the demerits of active crossovers. I tend to listen pretty loud in the living hall though when no one is around occasionally(80db average for short periods). The only thing in my experience that I can listen at really low volumes and be satisfied with is the HD800 as I have no particularly efficient speakers.

The disadvantages of active crossovers are simple: cost (and quality)

• Supposing a pre-amp feeds the active crossover (AXO) and the AXO splits the signal into bass, midrange, and treble, that means 3x amps. There are of course hybrid approaches such as using an AXO to split bass and above, and then using a passive for the mid/treble split.
• The AXO becomes yet another component in the chain, so the quality of the AXO becomes critical. I've stated that I feel passive crossovers suck the life out of music. Well AXOs can certainly do that do, especially if they are a bunch of op-amps slapped together. I think the only way I would do an AXO is with tubes (not because they sound lush, but rather because they provide clarity and immediacy which transistors and especially chips cannot.)
• One method I used in the past was to use the Behringer DCX2496 digital EQ/crossover. I took the low, med, high channels into 3 amps via a 6 gang pot. It was a good sounding system for cheap. Way better than the all Linn Activ system that I had previously owned, but for 30% of the cost. Ultimately, such a system would be limited by the quality of the DCX2496 because it also serves as the DAC. It's decent as a DAC. But not great. The DCX2496 however serves as a great subwoofer DSP processor / XO.

BTW, at this point, the only way I would do an AXO is this way:






Donald North is my hero. 'nuff said.