How Big Should My Subwoofer Be? (2 replies)
The answer to this question is simple, how much money do you have? Sorry, I don't mean to be crass. The truth is that the real question should be "How Big Should My Two Subwoofers Be?". You might have seen that coming. Proper subwoofer implementation is best done with two or four subs. I'll leave that discussion for another post. The real issue is that smooth bass means that much of the room gain is lost. Room gain meaning extra energy that comes from peaking standing waves in the room. So the boost your room gives your sub output also badly distorts the signal. Standard subwoofer calibration means placing the sub(s) to reduce standing wave distortion and following up with equalization. All these adjustments rob the sub of gain.
To compensate for the lost gain, you need capability; power and woofer size. I've definitely had to back off on bass smoothing more than once as the mild mannered subwoofer I was calibrating began running out of gas. And that's the long and the short of it; buy the most capable subs you can. That's the best way to make sure you have the powerful bass you want that is also musical and beautifully integrated into the system.
So keeping with the topic I would like to ask a theoretical question:
Assuming typical room size, and assuming unlimited budget and options for set up, what is the best or most ideal number, size and orientation?
Most there ever a point where there is too much or too many ?
I have often times seen many people revert to the proven effective orientation of 1/4 points (2 subs) and corners (4 subs) with success. But the recent trend with enthusiasts in the forums seems to be adding haphazardly additional woofers in random locations and labeling them "near field" and I often wonder if these people are creating additional complications in calibration or doing more harm than good.
Assuming (8) subs I would think it would be better to just keep with the corner placements and elevate some near the ceiling corners or stack them. Or perhaps some other configuration of the advantageous location multiples?
What is everyone thought on ideal configurations? Or numbers ?
Near field sub placement can be a solution for a couple of issues;
1) You have a space that is very large or open and a small budget. In this case, you lose a lot of bass trying to pressurize the room or, in the case of an open room, bass flying out the door. The sub will likely be loudest near it… solution bring the sub much closer the listeners.
2) The near-field response is very smooth. If you listen very near to the sub, the direct sound of the sub will be significantly louder than its reverberant sound. Presto! smooth bass.
The devil is in the details though. How close do you need to be to be "in" the near-field? Pretty darn close. Many of the examples of near field sub placement I've seen still have the sub far enough away that its reverberant sound (i.e. modal response) is still a factor requiring EQ and yet some of the distortion is not EQable .
We also have the seating to contend with. Its not practical to devise a near-field solution for more than perhaps a couple of seats… and where do you hide them? The there's the likelihood of sensing the air pressure modulation from the sub not to mention any artifacts that might be audible only if you're very close to the sub.
Bottom line is that I compare near field sub placement to wearing headphones. If creating smooth bass in a small room was amazing difficult I'd scratch my head to figure out how to implement it. Actually, as you mention, there are many more practical ways to set up subs that can yield smooth bass not just for a couple of listeners but for an entire group of listeners.
As far as the number of subs is concerned, 2, 4, 8, 16… all good. But you can't randomly place the subs and expect good results. More subs creates a more complex sound field which has the effect of smoothing response(primarily dips) and is good. The key to me is practicality in designing the best and most cost-effective solution for a client.