Using a Sub in a 2 channel only System w/ NAD int amp (1 Viewer)

[EricHM]

Hi, after some reccomendations from this board, I think I may be purchasing a NAD c350 integrated amplifer to power a pair of phase technology pc2 bookshelf speakers.
However, I would like to use an ADIRE AUDIO RAVA subwoofer in this system as well. My question is, with the NAD integrated amp and the rava sub, would I be able to send my primary speakers a hi pass signal while sending the sub a low pass signal? Would I need to purchase some kind of additional crossover? How would the mechanics of this work? Is the crossover in the rava sub capable of sending a hi-pass signal through it's rca outputs? Could I send this hi pass signal to the amp in the NAD?
I would really like to hi pass the phase techs if possible, because it has been my expereince that speakers tend to become more effecient and less suscpetible to distortion when playing a limited bandwidth.

 

[Jack Gilvey]

The only high-pass filtering the amp in the Rava performs is at the speaker-level inputs/outputs (I think it's first order @ 125Hz), which I would not recommend. Using line level or speaker level connections, a low-pass signal is automatically sent to the sub.
The only decent electronic HP filters I can think of, such as http://www.marchandelec.com

 

[Frank_S]

Eric, have you auditioned the Rel line of subs?
They integrate with your mains better than any sub out there and have a very nice method of connection.
[Edited last by Frank_S on September 18, 2001 at 11:45 AM]

 

[Henry C]

Eric,
I have recently purchased the NAD C350 and I love it. You can't go wrong with NAD.
I am also curious about your question. I would eventually want to add a sub to the system if possible. Could I use the cross-over from a PSB powered sub to add that to the system? I am not really sure how this all works, so if anyone can enlighten me, I would appreciate it. Thanks.
Henry

 

[EricHM]

Okay, apparantly the answer to my question is no, you cannot hi pass the the NAD amp without some kind of seperate external crossover. The crossover on most subs is 1 way low pass only, and the nad doesn't have any kind of hi pass filter built in as far as I know. So the only thing you could really do is have the nad playing full range and the sub playing low pass frequencies.
This is not optimal at all.
Perhaps the only way to divide the frequency range between a sub and the other speakers is with seperates or a reciever with a subwoofer preout. Denon makes a stereo reciever like this.....I also think B&K makes a stereo preamp with a built in 2 way crossover. Maybe nad is out for me then, because I really like the added bottom octave a sub gives you and would prefer not to keep my mains playing the bottom octave with the sub.
I would prefer to stay with the RAVA if possible, I use a sealed shiva in my car and really like the way it sounds.
[Edited last by EricHM on September 18, 2001 at 02:52 PM]

 

[Jack Gilvey]

So the only thing you could really do is have the nad playing full range and the sub playing low pass frequencies.
This is not optimal at all.

Oh, it's not all that bad, Eric.
If this is a music system, I'd stick with the NAD and Rava, depite the fact that the mains won't be high-passed (that's the way REL does it, btw). I'd be willing to bet that it will still sound better than any A/V receiver anywhere near the price. And you'd probably get a better blend with your mains, since you can adjust the crossover at your will, preferable lower. Fwiw, my NAD 314 sounds much better than my Onkyo 575x.
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[EricHM]

Oh, so the rel has a two way crossover? interesting.
This helps, but only if I can figure out a way for the signal chain to flow as follows:
Source - NAD C350 Preamp - REL SUB - NAD c350 AMP
I do not know if this is possible, but I'm guessing it's not because the NAD amp probably automatically see what the preamp gets.

 

[Jack Gilvey]

Oh, so the rel has a two way crossover? interesting.

No, what I said was that with the REL, the mains are not high-passed, they are run full-range, and the sub is dialed in under them, as far as I know. Sorry if it was unclear.
I'd just run a parallel set of speaker cables (I use the "B" speaker jacks) from the NAD to the Rava's high-level inputs (I use the same amp as the Rava in Link Removed

 

[Michael Roderiques]

Eric,
I am doing just what you want to do. I have an NAD 317 Integrated Amp. I like it a lot and so far have yet to run into anything it can’t handle.
Here are some things to look into. Does the Sub your interested in have a high pass crossover built into the sub. A large number of them do. At this time I have a Velodyne SPL1200 in the system. It does have a high pass in its crossover.
If the subs you are interested in do not have a line level high pass crossover, you may want to look into the Paradigm X Series
controllers. They are designed to work with the Paradigm subs, but they will work with any sub. The X-30 has line level connections and would be the unit of choice.
On the back of you NAD should be a set of Pre-outs and Main-ins. You should see a jumper between them. If you pull out that jumper bar, you have disconnected the signal path. Basically you now have a Pre-amp and a power amp.
You can then take the Pre-outs to the crossover input, then from crossover outputs back to the main-ins.
Now the system is high passed the main amp and the low frequencies will go to the sub