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Bi-amping advice needed - NHT ST4 and HK AV 325 (1 Viewer)


Jan 29, 2004
Hello to all. This is my first post... joined this forum about three years ago when I bought a new house and acquired some home theater gear. A busy life... a bit of lethargy... and then a death in the family.... all contributed to getting the gear unpacked, partially installed and then never used much until recently.

I finally joined the iPod generation a few months ago and bought myself an an iPod compatible Alpine unit as an upgrade for my Toyota circa 1992 factory care stereo. While browsing in the showroom of the installer I happened across a pair of NHT ST4 tower speakers - demo model closeout - got them for $500 (the pair) and now the fun starts!

My original setup (never fully hooked up):
Harman Kardon AV 325 (50 Watts x 7 at 8 Ohms)
NHT Super Ones for L and R
NHT Super Center
NHT Super Zeros in white for rear center pair
Boston Acoustics VRS Micro dipole surrounds in white
Separate subwoofer (don't recall the brand right this minute and I'm at work)

The room is small - about 7.5 to 8 feet across and about 14 feet long with 8.5 foot ceilings. I have a Panasonic 1080i compatible rear projection 49" television with just enough room for gear rack to the sides and the speakers.

The purchase of the ST4s prompted another purchase - two NHT A-1 monoblock amps and an NHT X-1 crossover. The ST4s have 8" passive subwoofers and are bi-ampable. I'm aware that it's not crucial to bi-amp for the .1 LFE channel in home theater applications but I also plan to use this setup for audio (20% audio - 80% movie watching). It's such a small room that I'm please to be able to get rid of a separate subwoofer.

The AV325 has three separate selectable crossover points for the front, center and surrounds and also has preamp outs plus a separate LFE out for the .1 channel.

The guy I bought the NHT amps from has some wiring ideas that will assist me with the bi-amping but I'm hoping you kind folks can steer me the right way on some other decisions.

1) Would there be any benefit to dumping the BA VRS micro dipole surrounds and getting NHT dipoles? It's my impression that timbre matching is not crucial on dipole surrounds and I don't want direct radiators due to the narrow width of the room. The VRS micros are nice and small and a perfect for for eh space where they are mounted. I think I can grab some used NHT dipoles if necessary but would rather not spend any more $$$ right now.

2) Any benefit to moving the Super Ones to the center rear space and then selling the Super Zeros or using them elsewhere? The 7.1 of the AV 325 has synthesized stereo for the rear center pair but I'm guessing it's not full range and has limited bass frequency.

3) Will it be possible to effectively wire this arrangement so I can have true stereo bass with the bi-amped ST-4s in stereo mode but also still take advantage of the .1 LFE channel when in 7.1 home theater mode? (I assume I woudl have dual mono bass in that situation).

Any and all advice appreciated. Thanks in advance!

Mark Russ

Second Unit
Jun 23, 2002

Actually, you would need the X2, not the X1 for the ST-4s.

Once you have the X2:

set main L/R to large/full range, hook AVR's main L/R speaker outs to top set of the ST-4's speaker wire binding posts

run AVR's main L/R pre-outs to the X2's L/R inputs

set all other speakers to small with whatever crossover point you will use for your CC and surrounds, then run AVR's sub/LFE out to the X2's LFE in

Set X2 to stereo on back

set X2's low pass all the way up as high as it will go to 220 Hz to get it as much "out of the way" as possible (your ST-4s have their own fixed, internal high and low pas crossover from the mid to the passive sub at 135 Hz). You will not be using the X2's high pass crossover at all when hooked up this way, so don't even worry about it.

Run X2's sub outs to each corresponding L/R A1's input and attach each A1's speaker wire to the appropriate L/R ST-4's bottom set of speaker wire binding posts.


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