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I bought my first self powered subwoofer, I hooked it up to my receiver and it does work but.....



1) On the sub what does the "PHASE" button do? Normal and Reverse? What do I set it to?



2) On the sub I have a "cut off frequency" dial, how does that work? All the way to the left is 50Hz and all the way to the right is 200Hz. Where should it be?



3) On the sub I have a "level" dial. Min and Max...I assume that is the sub volume, where should it be kept at?



4) On the receiver, I've put the BASS volume at 00. Right or wrong?



5) On the receiver, I've put the SWFR at 00. What does SWFR mean?



Please give me good explanations because this is all very new to me.



:confused:
 

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I'll let someone else explain phase that can do it better than I, but it is an adjustment to make your sub blend better with your speakers. You want them in phase with each other. I would say use which sounds better, but as soon as I do that, someone will post a specific test to do to get it correct without having to trust your ears.


The cut off frequency is a low pass filter. You want to cut off frequencies that your other speakers can play well. Usually this is between 60-80 if you have decent size speakers. "Bose like" speakers will be closer to 100-120. The higher the number, the higher the frequency the sub will play, AND the more noticable the location of this sound will be. Lower is better if your main speakers can play the lower notes. If your speakers can't play the lower notes and you set this too low, you will have a "hole" between what you speakers produce, and where the sub begins to kick in.


Set the level on the sub close to the same volume as your other speakers. A Rat Shack meter works well.


I'm assuming this is for the LFE (low frequency effects) channel. That is the ".1" channel put on DD and DTS encoded material. If it is actually a LFE adjustment, you'll have to use a meter or your ears to see if you want more or less while watching movies.


Use the receiver to fine tune your subwoofer level after you have gotten it close on the sub itself.
 

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Quote:
Originally posted by Angus Kirby
1) On the sub what does the "PHASE" button do? Normal and Reverse? What do I set it to?
Set it to "normal" for now. It is a switch that reverses the polarity of the sub -- just like you would be reversing the polarity of one of the other speakers if you hooked up the negative wire to the positive terminal and positive wire to the negative terminal. This setting can have a minor influence on the crossover region, but let's not worry about that now. We've got bigger fish to fry.

Quote:


2) On the sub I have a "cut off frequency" dial, how does that work? All the way to the left is 50Hz and all the way to the right is 200Hz. Where should it be?


3) On the sub I have a "level" dial. Min and Max...I assume that is the sub volume, where should it be kept at?


5) On the receiver, I've put the SWFR at 00. What does SWFR mean?
These are all part of the same question. A Dolby Digital receiver has a built-in digital crossover. The purpose of this crossover is to redirect the bass from each individual speaker to the powered subwoofer because the subwoofer is better at playing bass and because any distortion from loud bass notes will no longer be heard through the other speakers.


The way this happens is "bass management". You set all of your speakers to "SMALL". Small is the codeword to tell the receiver that you want the bass from that speaker to be redirect to the subwoofer.


Since you have a crossover in the receiver, you don't want to use the additional crossover that is built into the subwoofer. Hopefully, your subwoofer has a switch or an input that bypasses the crossover. If not, then you set the "freq" knob on the subwoofer to the highest possible setting since you really don't want it to be doing anything.


You have two volume controls for the subwoofer. One is in the receiver labeled "SBWFR" -- probably on the same menu with volume settings for the front, center, and surround speakers. You also have a volume knob on the back of the subwoofer, but this one is not very convenient to use. So the idea is to set the subwoofer knob in the ballpark and then make final adjustments with the one in the receiver.


Here's how you do that (after setting all your speakers to SMALL in the receiver:


1) go to Radio shack and buy their $29 analog SPL meter.


2) Bring it home, put the dial on 70, and put the switches on SLOW and C-WEIGHT.


3) Mount it on a tripod or otherwise jury rig it so that it is resting at your listening position, pointed at the ceiling.


4) Play the pink noise test tones in your receiver through the left front speaker and adjust the master volume control until the meter reads +5 dB (75 dB).


5) Move the pink noise from speaker to speaker and adjust the individual volume controls in the receiver until every speaker reads exactly the same thing, without touching the master volume control.


6) When you get to the subwoofer, adjust the knob on the back of the sub until you are close to the same volume (+5 db) on the meter. Then, use the SBWFR adjustment in the receiver to set the subwoofer to read about +2 dB on the meter. You'll have to estimate because the needle will probably be bouncing around a bit. Just try to guessitmate and average.


Now, you are done, with subwoofer levels in the right ballpark and a properly calibrated system.


If you want to go back to that Phase switch, try it in both positions and leave it whereever it sounds like the system has more bass.

Quote:


4) On the receiver, I've put the BASS volume at 00. Right or wrong?
This is probably just a cheesy tone control. There's probably a cheesy TREBLE control along with it. I wouldn't use them. In most cases, they don't work with Dolby Digital signals anyway.
 

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Quote:
Originally posted by Angus Kirby
I bought my first self powered subwoofer, I hooked it up to my receiver and it does work but.....
If I may add to HWC's excellent responses:
Quote:
1) On the sub what does the "PHASE" button do? Normal and Reverse? What do I set it to?
The term "phase" refers to the nature of sound, and the motion of a speaker cone while reproducing that sound. Sound travels through space by alternately compressing and rarefying air. Speaker cones do the same thing by moving toward and away from the listener. When different speakers' cones compress at the same time, they are said to be 'in phase', and the sound waves add in strength, and when 'out of phase', the effect is subtractive (aka cancellation). The setting with stronger bass is usually the right one, but sometimes, there is a room-caused 'hump' in the bass region that can be reduced by intentional 'mis-phasing'.
Quote:
2) On the sub I have a "cut off frequency" dial, how does that work? All the way to the left is 50Hz and all the way to the right is 200Hz. Where should it be?
That control determines the frequency at which the sound will be reduced (by 3 dB, usually) when the frequencies exceed that setting, and the rate at which this happens (in dB per octave) is called the 'slope' of the crossover.
Quote:
3) On the sub I have a "level" dial. Min and Max...I assume that is the sub volume, where should it be kept at?
This is determined by ear or meter, and should be done after phase setting, but with all other controls 'zeroed out'.
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4) On the receiver, I've put the BASS volume at 00. Right or wrong?
This is probably correct, as HWC says. It's a preference thing, really.
Quote:
5) On the receiver, I've put the SWFR at 00. What does SWFR mean?
That's the receiver's LFE output level control. Set only as HWC mentioned, to adjust sub-base after initial setup.
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Please give me good explanations because this is all very new to me.
That's why we're here! If you don't quite grok something, ask again.
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:confused:
 

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All of you have explained it very well and better than i could have done it. I must say I am proud to be a member here. Nuff said.


You should definitely check out this thread on subwoofer placement. Placement is essential for good subwoofer sound. Actually I'd work on a crossover setting first approximatively than work on placement and then regulate the entire thing once it is in a good place.


There is a series of articles in one post by me that are very useful. I've read most but not all of them. If you read all of them you are the expert.


Here's the link: http://www.avsforum.com/avs-vb/showt...36#post2014736


Enjoy,


Till
 
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