Like

Why do you need a Subwoofer?

 

Silver Member
Username: Superjazzyjames

Post Number: 436
Registered: Oct-10
Of course using a subwoofer is a matter of personal preferance and the bass performance of your speakers. However, I always encourage the use of a properly tuned subwoofer.

The original concept of the subwoofer (early 70s, I believe) was to seperate the deep bass from the main signal. This was done using a third woofer and you had to be able to DIY. If your main speakers had 12" inch woofers, you might buy a 15" woofer, mount in a box along with crossover and mixer. You would then run the speaker outputs on your amp to this woofer and to your main speakers from there. The reason to do this was to allow the woofers in the main speakers to handle the mid and upper bass while the other woofer handled to deep bass. As intended, this resulted in cleaner bass. It also cleaned up the rest of the sound.

Around the late 80s the subwoofer driver was introduced for consumer use. The subwoofer was able reach lower frequencies than the woofer due to a larger diameter voice coil, magnetic field strength and other factors. This added a new level of realism to music and since home theater was in its infancy and movie sound tracks need good bass performance in order to acheive realism, the timing was perfect.

The 1st generation of subwoofers was problematic. They operated, for the most part, on the same principal as the third woofer. In other words, they were passive. However, subwoofers are very greedy. Therefore, they "ate" all the watts! Whenever any deep bassy sound was presented, the volume of the rest of the signal would dip significantly taking away enjoyment of music and movies.

The answer was the powered (self amplified) subwoofer. By giving the subwoofer its own amp, the problem of the sound dipping was solved. Another solution is to power a passive sub externally. Unfortunately, the original purpose of the subwoofer was essentially lost since most people no longer filter sub bass away from the main speakers. Doing so is important for realizing the full benefit of using a sub.

The percieved need or desire for a subwoofer depends greatly on the bass performance of your speakers and the primary use of your system. The better the bass performance, the less need/desire for a sub. People who use their systems primarily for movies, will be more inclined to use a sub than those who use it mostly for music.

So, while I always encourage people to use a subwoofer, I also recommend filtering the sub bass away from the main speakers. In order to integrate a sub into a system (properly tune both the sub and the system), it may take several hours and involve moving the speakers and sub to different locations around the room, adjusting crossover/filter frequencies and the subwoofer level. Once done however, the system should sound terrific.

Again, ultimately it's up to you!
 

Silver Member
Username: Superjazzyjames

Post Number: 451
Registered: Oct-10
If it all possible, the sub bass should be filtered away from the main signal. This can be done with a receiver, integrated amp or preamp with a subwoofer output. It can also be done by passing the signal from a preamp through an electronic crossover and sending the main signal to the power amp and sub bass to the subwoofer.
 

Gold Member
Username: Magfan

USA

Post Number: 1884
Registered: Oct-07
The OTHER approach, and just a succesful for the stereo crowd is to run the main speakers 'full range' and cross the (powered) sub over as low as practical.
I cross mine over at or below the 'spec'd' lower limit for the speaker.
This minimizes both speakers playing the same frequencies while picking up the lower octave or so. There is no bloat or accented bass. The stereo stage is much wider and deeper.

I'm not familiar with HT, but I do know you've got the choice of 'large' or 'small' main speakers which effects how the sub output is handled. I'm personally not big on the 80hz crossover frequency which I hear so much about. That frequency does make sense, however if the mains are somewhat less than .....robust.....from 100hz on down.

To me, and I'll admit it's the 'cost no object' solution and beyond the scope of most people who simply want music and movies, would be an active crossover with the LF removed from the main speaker output. The sub could than cross over a little higher, but at that point I'd want 'stereo' subs. The power saved by the main amp can be considerable and than given to the rest of the spectrum.
 

Silver Member
Username: Superjazzyjames

Post Number: 492
Registered: Oct-10
Your approach works too Leo. Again personal taste. Certainly, if filtering out sub bass is not an option or not what you want to do, having the sub go where the mains can't is a good option too. This approach adds realism by extending the bass down to the deepest levels.

I was using 80 Hz at one time simply because it worked for the speakers/sub combo in the location they were in. Once I moved, same spkrs & sub, 50 Hz worked better.

You're last approach would be best for those who can (cost no object indeed). This approach certainly does take pressure off the main amp too. It's all about doing what you can and are inclined to do to get the desired sound. Stereo subs are best whenever possible, especially as the crossover frequency goes up. My receiver has a mono sub out and since I prefer to use it rather than speaker level keeping the frequency low is almost a necessity.
 

Silver Member
Username: Nency

Post Number: 101
Registered: May-09
The typical frequency range for a subwoofer is about 20--200 Hz for consumer products,
1] below 100 Hz for professional live sound,
[2] and below 80 Hz in THX-approved systems.
[3] Because of their limited frequency range, most subwoofers are used to augment the output of loudspeakers covering higher frequency bands.
 

Silver Member
Username: Superjazzyjames

Post Number: 697
Registered: Oct-10
"The typical frequency range for a subwoofer is 20 to 200 Hz."

Most subwoofers don't go all the way down to 20 Hz. Those that do are rather expensive.

You're layout of the standard setting does not take into account the fact that every room, speaker and ear are different. If my current system in its current location was tuned with 80 to 100 Hz as the crossover point between sub & mains, the bass would be overwehlming. I'll stick with 40 Hz herein. Thanks!
 

Silver Member
Username: Superjazzyjames

Post Number: 707
Registered: Oct-10
Before you say it Leo, I know! Your sub goes down to 18 Hz according to the specs. It probably goes lower. I know, I've got it. Okay?
 

Gold Member
Username: Magfan

USA

Post Number: 1923
Registered: Oct-07
Wasn't going to say that at ALL. Please, try not to anticipate my answers.......

That being said......200hz at the upper limit? You'd need a pair of subs if you went that high. At that frequency, they'd easily be found by ear.
Not to mention the rest of the sonic problems depending on where the main speakers left off.....

HSU makes a mid-bass driver.....Maybe that's worth a look?
 

Silver Member
Username: Superjazzyjames

Post Number: 709
Registered: Oct-10
I think Nency is just pointing out that some subs can go that high. I used one with a TV once with it set to 200 Hz. I put the sub behind the set. At that time the VCR was still in my wife's system. I wanted to watch "The Godfather" and TV speakers alone? NOPE! It was decent.

As for the 18 Hz sub, lighten up okay? You do point out exceptions a lot.
 

Gold Member
Username: Dmitchell

Ottawa, Ontario Canada

Post Number: 4526
Registered: Feb-07
"The OTHER approach, and just a succesful for the stereo
crowd is to run the main speakers 'full range' and cross the (powered) sub over as low as practical. "

I like this approach, or rather liked, back when I ran a sub in my 2 channel system.
 

Silver Member
Username: Superjazzyjames

Post Number: 733
Registered: Oct-10
Again David, personal taste. I just like pulling some sub bass out of the mains. I find the music is cleaner and less veiled that way.
 

Gold Member
Username: Magfan

USA

Post Number: 1928
Registered: Oct-07
Super,
I'm not worried about the diff between 18 and 20 or whatever.

My question concerned the 200hz upper limit.....pretty high, in my estimation. and locatable, meaning perhaps you'd need a pair or some real ingenuity in placement...and some luck.
That's the 2nd time you mentioned something claiming I did....and really didn't. (your #707)

The HSU mid-bass driver? Easily goes to 200hz, but will need a real sub go .....subterranean. HSU packages it as part of a system.
Never heard it.

You should probably lay off the Martini's or whatever your drinkin'.
 

Silver Member
Username: Superjazzyjames

Post Number: 762
Registered: Oct-10
I agree Leo that 200 Hz will have the problems you mentioned. That's why when I used the sub with the TV, I put it behind the TV and turned it sideways. Using TV speakers as sats, needs max bass coverage. At 200 Hz, you either need stereo subs or to keep back like I did with the TV. I wouldn't normally use 200 Hz with a system for a number of reasons.

I'm just expressing my preferences Leo and trying to have a little fun while I'm at it. I think you could use a couple of drinks, get a nice buzz....
 

Gold Member
Username: Magfan

USA

Post Number: 1929
Registered: Oct-07
Nah, I'm a type 'a' personality and have even given up sleep.
 

Silver Member
Username: Superjazzyjames

Post Number: 794
Registered: Oct-10
Lol! That explains a lot! I wasn't drinking yesterday btw, just in one of those moods.

Remember, what you do with your system is only wrong if you don't like it.
 

Gold Member
Username: Magfan

USA

Post Number: 1936
Registered: Oct-07
'in one of those moods'?
Lithium may help.
 

Silver Member
Username: Superjazzyjames

Post Number: 871
Registered: Oct-10
Lol! Stop it!...You're killing me! Which part of "I'm not bipolar." don't you get Leo?
« Previous Thread | Next Thread »

Add Your Message Here

Bold text Italics Create a hyperlink Insert a clipart image Add a YouTube Video
Need to Register?
Forgot Password?
Enable HTML code in message
   

Facebook

Shop Related Deals

Directory

Main Forums

Today's Posts

Forum Help

Follow Us