HT/Subwoofer Question

[robforst1]

My sub really shakes the room when watching DVDs. In fact, I am a little concerned about blowing out the large window in our Media Room.

The problem is, I am not sure if the volume and crossover are set for optimal effect. I have the crossover set at about 80 and the volume about 3/4 up. Is there a simple way to tell if the sub is set-up correctly?

Rob

[Colin]

If you had the volume and cutoff frequency adjusted so that you could "hear" the subwoofer(s) doing something, then you probably had them set at too high a level and cutting off to late. A properly balanced sub should be *INAUDIBLE* almost all the time, and only noticed by its absence when you turn it OFF.

Placement of your sub will depend on how you have the subs crossed over with your mains. It depends on the EQ setting. The higher the crossover, the better the sub-woofer will perform in line with your other speakers. The reason for that is because much of the notes that a powered sub-woofer makes are locatable by ear. That is, you can close your eyes and tell where the sub is. This can help with the image. Putting the sub where it adds the most impact to the sound image is in direct opposition to the idea of putting it where it can get the deepest notes. They are not the same thing.

If I wanted the artificial low notes that they use in movies, I would place the sub in the corner of two solid walls. If I wanted the mid-bass punch that they have in music and movies though, I might locate the sub closer to the center of the soundstage.

Speakers with a high bottom end, like satellites that only reach down to 65 Hz or more, will not image very well unless the sub-woofer is placed center stage. The reason for this is that they have little of the bottom end of the musical range (40 Hz and below).

Of course, the ideal compromise between sub in the middle and sub in the corner is to get two subs. One for each corner. That way you will get both depth and mid-bass definition and punch.

The subs have to be dialed up behind the music so that most of the time you have no idea they are even there. (This makes the little green light on the front a very nice feature. A remote control would be a wonderful feature as I am constantly dialing sub volume over the top for action movies and down for music.) The best way to do set a flat response level on a sub is with a test CD and a Radio Shack SPL meter. I did dial a flat frequency response before I used the meter, but it was just as they said, so low that you do not hear the sub.

The trick that I have learned over the years is to stand near the sub. Then dial the bass response up until it begins to sounds boomy with the music, then back off the volume until it doesn't boomy at all (it may disappear so much that you think that you are not getting any bass). When you return to your seat however, you will find that indeed, the sub is helping out in the mid-bass range.

[Q-Man]

I agree with Colin.

You should never know that your sub is on. That will lead some to believe that it isn't loud enought.

Sometimes I turn off all the speakers to hear what the sub is doing. Then there are times that I'll turn off the sub and hear what the speakers are missing.

[Mlstrass]

Is there a simple way to tell if the sub is set-up correctly?

Rob

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YES....with a set-up disc and SPL meter. Doesn't get much simpler than that!

[robforst1]

Thank you for the very complete answer!

On another note, what do you think of the tube amp kit you are using. I am thinking about buying one. How difficult was it to put together?

I have no experience at anything like that...

Rob

[boa12]

rob, your yammy is already digitally filtering the sub at 90hz (assuming you have the sub attached to its sub preout). so you may not want to use the crossover on the sub or you'll possible cut some LFE. iow, turn it all the way up to its highest hz setting or switch it out if it has something like a crossover disable or in/out switch.

or if you want to use the sub's crossover to get the corns to jive better w/ it for music, you want want to wire the sub speaker level in parallel to the corns. then set the sub to "fronts". or you can also do the sub line level off the front preouts.

[prodj101]

odd, maybe defective, but maybe hte input signal is so strong it just doesn't matter.

[mmiles]

boa12,

i have a yammy v2200 same with me on the crossover issue?

[boa12]

mm, actually it goes the same for every receiver or pre/pro i can think of when you're hookin the sub to its sub preout - the digital signal processor (dsp) filters the sub out (digital low pass crossover) at either a variable point adjustable in the receiver/prepro controls, or at a fixed point usually around 80hz. believe most yammy's use a fixed 90hz for the sub & as a high pass for the speakers set small.

also, yammys like most have the configuration where all LFE is sent to the sub out only unless you set it to "fronts" & then nothing is sent to the sub out. that's the equivalent of setting sub:no in most other units.

so to avoid dueling crossovers/double filtering/cascading & such, & cutting LFE which is speced

up to 120hz, best to not use the sub's crossover when you're using the sub preout for the sub.

[boa12]

rob, actually meant to add as for your intitial concern, it sounds to me like the sub output is turned up too high. colin & ml had good advice there - get it calibrated w/ a sound meter.