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hooking up a sub

Clmrt said:
If I'm wrong, say so. If you know better, explain it better than I did.
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You are wrong. Search "Lexicon" under Zilch.

We're allowed to have fun here, I believe. :yes:

I've deleted the post, as it offended you, but the word will ultimately appear in context, and you will be credited.... :thmbsp:
 
Yeah yeah, pointy caps. Remember that?

:headscrat:withstpd:

LOL

Kerfutz = Mess with it.

I thought it was Armenian for "Dumbass".
 
just make sure you use a sub like Epos or JL as there is a massive differance between a sub made for 2 channel and a movie sub.
 
Interesting thread. I have a question regarding my NHT SW1P with the SA1 amp. Hopefully this doesn't hijack the thread as it is about hooking up a sub.

I have tried hooking it up to my Denon PMA 920 a few different ways. First with the speaker outs into the sub amp and then to the speaker switcher then to the mains mains. Then with the preamp section y's off to the main amp and the sub amp. Then with the main speakers into the switch box and the to the sub and out to the mains.

With any of these setups it was like the sub amp wasn't pushing any power. It is the 90 watt version. I realize this isn't massive power, but I did think that it would be able to push the sub so I could hear it over the mains, if I wanted to. The sub volume is varied by the preamp section as if it is controlling the gain and the sub amp is a passive amp. The sub amp has a volume knob, but I have to keep it at max volume to even hear it unless I crank the preamp and main amp and run myself out of the room.

It doesn't seem very useful if this is how it should work. At moderate volumes if I put my head to the sub when the mains are switched out I can barely hear it and all I get is a muffled bump, bump. If I turn the crossover higher, then I do get more of the signal, but it is not louder just more frequency.

I can at times feel the room rattle and things shake a bit, but I can't really hear anything. I thought it would be like a car sub if I set it too loud. Is this the way it is supposed to be?

Does this make sense? What am I doing wrong. I can't ruin the sound because I can't get the sub loud enough to make a difference. :scratch2:

Maybe my small room is sucking the low bass out. 8.5x15. I get decent bass from my main speakers.
 
VinylHanger,

Please expand on what you're doing with the speaker switcher exactly?

Have you tried removing it from the equation and just running a single pair of speakers off the power amp's outputs while using your Y-cables at the preamp to send line level to both the power amp and sub amp ins?

If setup correct, you should be able to adjust your sub amp volume to about the middle (or less) and have all the bass you want when you adjust the regular preamp volume which will control your mains and the signal going to the subwoofer. Having to crank your subwoofer amp all the way doesn't seem right especially if when doing so produces little noise.
 
clmrt,
did i miss something? :scratch2:

don't get me wrong. i really do appreciate all inputs and thoughts. i do take all inputs seriously and try them for myself, and i appreciate your thoughts. i'm in no position to criticize for i have not enough knowledge to do so.... that's why i asked the question in the first place.
 
goraman said:
just make sure you use a sub like Epos or JL as there is a massive differance between a sub made for 2 channel and a movie sub.
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hmmm.. never thought about that.
are velodynes usually for 2 channel or for HT?

i've seen a few on craigslist and ebay within my budget.
 
When I y's the pre signal I went to the sub amp and out to the sub. With other end of the y, I went to the Denon's amp section. Then I sent the Denon's speaker out into the speaker switcher so I could switch between the Mission 770's and the Klipsch KG 3.2's.

Do you think it could make a difference? I would think that the sub is still getting the same signal, especially when I turn off the speakers. It is as if the sub amp is just a passive crossover. The louder I run the pre, the louder it gets. But if I feed it a low volume signal, it won't raise the volume of the signal any significant amount.

I'll try it though, as I would love for this thing to work.
 
VinylHanger said:
When I y's the pre signal I went to the sub amp and out to the sub. With other end of the y, I went to the Denon's amp section. Then I sent the Denon's speaker out into the speaker switcher so I could switch between the Mission 770's and the Klipsch KG 3.2's.

Do you think it could make a difference? I would think that the sub is still getting the same signal, especially when I turn off the speakers. It is as if the sub amp is just a passive crossover. The louder I run the pre, the louder it gets. But if I feed it a low volume signal, it won't raise the volume of the signal any significant amount.

I'll try it though, as I would love for this thing to work.
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I wonder if that halves your preamp voltage. If it were a problem, you'd notice it in the Denon, too, I suppose. Strange.

I used an SA-2 once, with an SVS 20-39, and that was a great amp.
 
Interesting, yep it sounds like you've done it correct. You already likely have found this, and it's for a slightly different model than you have, but "method #2" according to the .pdf should get you connected with the high pass filter sitting between your amp sections:

http://nhthifi.com/current/manuals/vintage/sa_2Man.pdf

If that doesn't work, then maybe the SA1 has got a problem of some sort?
 
If you have a receiver or other amp you can do the same thing, to see if the behavior is unique to the NHT.

Run the sub signal to an AUX input, flatten the tone and remove the loudness, blah blah blah.
 
Jon_Logan said:
huh?:scratch2:
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Car subs are known to be better musically than movie subs.

I really don't know what his post meant, but I suspect he is just saying to get very high quality, exceptionally expensive subwoofers. I tend to take the opposite approach. Good subs are easy to find, and not expensive. They key is implementation in your room, and having enough of them. 3 well positioned subs will get you to where you want to go, more is better but you run into diminishing returns.

Keep in mind that bass freqs in normal sized rooms are so long that you are actually moving from waves to actually high and low pressure zones. Having multiple subs allows you the capability of ensuring uniform bass response throughout the room. The easiest way to get great bass is simply to have one sub in each corner, it works almost always. The goal isn't to have a boom box, a loudness button effect or a "movie" sub. If set up correctly, you won't notice they are their until they are turned off.

One thing that most people try to do which is almost always a hopeless endeavor is to run subs immediately next to or beneath their mains. Or, they attempt to use mains with subbass capabilities. the issue with this is the optimum position for subbass reproduction and higher freqs is not in the same location. Mains that can produce subbass are nice, because they can take care of a part of the subs function of even bass distribution, but it's usually easier to take care of it separately for more flexibility sake.
 
Most subs are made to spike at 50hz to 60hz as much as 20db then drop like a rock from a plane at 30 to 20HZ.Movie subs are ported and often have a longer excursion.Makeing them slow and rumbleing not fast and accurate. A sealed 10 inch car sub will out preform most surround sound subs.One of the better of these movie subs was a horn loaded Yamaha with 2X8inch fast fireing subwoofers it had a switchable Xover for 2 channel but could not go much past 28hz. and was -6db at 30hz.
 
goraman said:
Most subs are made to spike at 50hz to 60hz as much as 20db then drop like a rock from a plane at 30 to 20HZ.Movie subs are ported and often have a longer excursion.Makeing them slow and rumbleing not fast and accurate. A sealed 10 inch car sub will out preform most surround sound subs.One of the better of these movie subs was a horn loaded Yamaha with 2X8inch fast fireing subwoofers it had a switchable Xover for 2 channel but could not go much past 28hz. and was -6db at 30hz.
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This is one of the most ridiculous posts I've ever read. I don't know of a single sub designed to do this. Almost everything posted is false. Car audio subs tend to have strong motors and very heavy cones and massive power handling/excursion to allow very small sealed enclosures. They really on the power available and the cars cabin gain to produce deep bass. Take it out of that environment and say good bye to your bass extension.

There is nothing inherently wrong with a ported subwoofer. Plenty of them are musical and in some ways, they have more linear behavior than sealed subs.

Horn subwoofers act like conventional speakers at subbass frequencies and there is absolutely no correlation because cone diameter and "speed".

Other than that, Right on!
 
Some subs do work well in both Zilch. There are just a good majority of subs for cars with an Fs up in the 35-40 hz range which makes them a no go for me in a home unless as a woofer in a 3 way or something to that effect. For a home sub, I look for real world 20hz extension and preferably lower.
 
gogofast said:
thanks markw.
i've heard a few set up with subs and i thought it was a totally different experience.

so, what's the rule of thumb when setting the sub xo point?
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Everything below about 80 hz is non-directional sound, so that's one rule of thumb. Putting things simply, if you have one sub and can hear where it's placed in your room, it's probably either too loud relative to the mains or the sub xo/cutoff is set too high.

You might want to try just checking the low freq rating on your mains. Since they will begin to drop off significantly above their lowest rated frequency, you can start the sub cutoff around there and do some listening. You can dial up from there to your liking.

Experiment and your ears will tell you. I don't know, maybe you want it to sound like some car subwoofers do, and rattle the windows. in that case turn it all wide open. :D
 
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