Originally Posted by mnc
Well, I've since tried to simplify my setup and use my amp to power my towers full range. It really sounds nice. I can now use the pure direct mode for music. The sound is smooth, dynamic, and less fatiguing.
However, there is a noticeable drop in bass. I don't know why, but my speakers had WAY more bass before. Any help?
I downloaded the speaker's user manual from http://www.nhthifi.com/ServiceCenter/VT
and it explains quite a bit.
Your speakers, as you seem to grasp correctly have two modes of operation. The simplest way to use them is to jumper the two sets of banana jacks together and use it like it was a ordinary more-or-less full range speaker.
A possibly improved way to use them is to remove the jumper which requires the use of a second power amplifier connected to the subwoofer output of your AVR. One complication of this is that the speaker has some kind of a crossover inside of it that is always affecting the operation of both parts of the speaker. The subwoofer has some kind of low pass filter, and the upper range drivers have some kind of high pass filter and both filters are permanently wired in.
This makes the use of your speakers with a modern AVR more complex because there has to be some kind of coordination between the crossovers in the AVR and the crossovers in the speaker.
I see multiple references where NHT says that the speaker's internal crossover is 125 Hz, so I understand your consternation when YPAO comes up with a 200 Hz crossover.
One possibility is that NHT built a different speaker than they say they did which would not be much of a problem if used as they seem to have intended in the early 2000's when it was introduced. For example the permanent low pass filter on the semi-subwoofer may interfere with LFE usage if @ 125 Hz. Raising the crossover frequency would improve the dynamic range of the midrange speaker driver in the system.
Another possibility is that your room's acoustics are affecting what YPAO's microphones pick up in such a way that YPAO is getting a different idea about what the speakers are like.
As others have pointed out, using your AVR in direct mode may pretty well kill the subwoofer output of your AVR unless it is used with a source that itself has 5.1 analog outputs, such as some more expensive blu ray players.
It may be that your speakers are mismatched enough to a modern environment that using them as plain old full range speakers with the jumpers in place and avoiding the use of an outboard amplifier may be your best idea.
You could then add another subwoofer to exploit the bass management of your AVR, which could be a good idea. The 10" so-called subwoofer in the VT-2 is not very substantial by modern standards. Your outboard power amp may end up being excess.
It may also be true that your system could work if you hooked your power amp to the front L & R outputs jacks on your AVR instead of the subwoofer output, set your speakers for large, and adjusted the gain controls of your HCA 1200 amplifier for desired bass balance. This would put the passive crossovers in your speakers into the driver's seat where they may belong. This would not give you a lot of benefit in terms of offloading your AVR. and the benefits may not offset the extra complexity.