I used to have the impression that bigger subs are always better, I would rather buy a big sub and play it in low volume than playing a small sub at full volume but I read somewhere, don't remember where, that subs need to be bought according to room size - getting a bigger sub than needed will mean it will sound good outside the room, not inside. Is this legit and if so can someone clarify or explain the science behind it?
I think its a myth. People have big subs in their cars and still get a good sound. Problem is practical, big speakers in a small room makes proper placement harder beacuse of lack of space.
There is something in it. Bigger subs can generally produce lower frequencies, and if you go low enough to hit your first room node, you will have problems. You can notch that frequency out with either analogue or DSP to get round it though
Brian
Brian
What Brian says is similar to my comment. A big woofer can work fine in a small room, but they are often tuned without consideration of the room, and a small room gets overloaded. The woofer needs to be tuned to the application.
Perhaps a low Q sealed solution that takes maximum advantage of room gain.
dave
Perhaps a low Q sealed solution that takes maximum advantage of room gain.
dave
I use a pair of 30" in the direct field of an OB configuration, and never found any technolology able to rivalize with them, they sound flat down to 15Hz.
The motors are acutating enough weight and an enough air volume that had reach the ablity to be mechanically coupled with everthing at less than one meter, the solids are bending and you can feel the acoustic energy on your skin but there is nothing after two meters, the room and its modes don't exist anymore.
A large radiating surface sur is enlarging the direct field, it will not sound better by this parameter only.
The motors are acutating enough weight and an enough air volume that had reach the ablity to be mechanically coupled with everthing at less than one meter, the solids are bending and you can feel the acoustic energy on your skin but there is nothing after two meters, the room and its modes don't exist anymore.
A large radiating surface sur is enlarging the direct field, it will not sound better by this parameter only.
The ideal goal is to have a sub system that rolls off at the inverse of the room's gain curve to sum flat to the room's fundamental mode [~ SoS/2/longest parallel dimension], so ideally a sealed alignment of the proper Qtc or at least DSP'd sealed, vented with a low enough Fb regardless of size and why Dr. Geddes' multiple [small] subwoofer system is the way to go.
The room size 'myth' is based on the XO point, sub's directivity, so the higher the XO point and/or the larger the driver and/or box the greater its directivity [DI, AKA 'throw'], ergo will need to be increasingly further away for max performance/pleasure.
Unfortunately, consumer manufacturers don't provide a speaker's [DI], so again, Dr. Geddes' using a bunch of little 'blocks' to create an immersive 'wall of sound' is the best overall solution. 😉
Small subs can sound very good in a bigger room. Factor in how well the sub is designed and how well it does what its supposed to do. Too large of a room can easily drowned a sub.
Although a big sub will sound better in a small room, if you were to directly compare them the second scenario will out perform the other . Volume/ gain is your best friend here. With subs less is always more, and more than whats often needed to sound spot on. I've never had to push subs anywhere close to the full potential. Reason being thats the fastest way to get them to sound sloppy. And it is not necessary to achieve optimum sound. I'm speaking for music.
Other than that I plan to mix the sizes up this go, starting with small 8's, 2x2
The starting point, one itty bitty 8 with 10" PR. I'm running all of them with individual hypex dsp plates. Speaking of I hope that plate hurries up.
Although a big sub will sound better in a small room, if you were to directly compare them the second scenario will out perform the other . Volume/ gain is your best friend here. With subs less is always more, and more than whats often needed to sound spot on. I've never had to push subs anywhere close to the full potential. Reason being thats the fastest way to get them to sound sloppy. And it is not necessary to achieve optimum sound. I'm speaking for music.
Other than that I plan to mix the sizes up this go, starting with small 8's, 2x2
The starting point, one itty bitty 8 with 10" PR. I'm running all of them with individual hypex dsp plates. Speaking of I hope that plate hurries up.
Attachments
I learnt over 40 years that subs should 'Move a lot of air - GENTLY' and nothing since has swayed me from this ethos. An 8" driver flapping around close to Xmax is never going to sound as good as an 18" barely moving, plus a larger driver couples better with the acoustic impedance of the surrounding air. Think of the size of acoustic instruments which produce lower frequencies; there is good reason that they are large!
I don't believe bigger subs do not sound good in small rooms but there is a factor that, in this particular climate, I'm surprised nobody has considered. I'll use extremes to make the point. A good 15" driver can give you 100dB for your 1 watt. A JVC NXF7W subwoofer (6.5" driver) offers just 76dB for the same input. Subsequently, you're going to have throw a couple of hundred watts at the JVC to produce what the bigger sub can do with just one.
I looked into this after researching PC graphics cards, some of which are costing $300 per year to run.
I looked into this after researching PC graphics cards, some of which are costing $300 per year to run.
Good point, and for anyone considering multiple small drivers vs. one large one, the displacement volume per unit cost usually favours a single larger driver. 21" units are becoming increasingly common on the PA front as more and more manufacturers offer them. Powersoft even make a 40" cone for their M-Force Moving Magnet Linear Motor Transducer money is no object!
When considering woofers one should always remmeber that 2 woofers the next size down, loaded push-push, can dramatically improve box performance by actively cancelling reactive energy of the driver moving.
So 2x18 makes a lot more sense than a single 21”.
dave
So 2x18 makes a lot more sense than a single 21”.
dave
Noice. Push-push will not have the same displacement/area, or you mean separate woofers just working near each other? Could you post some example for better understanding? Thank you very much.
No i mean two woofers mechanically opposed, acousticlly in phase.
Whether (2 x size-1) has greater Vd than (1 x size) depends on the woofers choosen. It should be close with similar woofers. And that does not take into account the dramatic reduction in box vibrational load. The benefit of that is HUGE.
dave
Whether (2 x size-1) has greater Vd than (1 x size) depends on the woofers choosen. It should be close with similar woofers. And that does not take into account the dramatic reduction in box vibrational load. The benefit of that is HUGE.
dave
I see. This good advanced stuff/magic. Everyone is thinking about coupling just for radiation area purposes, but there are much more consequences in such setup, that are usually unknown, and not talked at all.
KEF explains very well advantages of using an arrangement of two subwoofers in one box at their whitepaper. Yeah, It’s marketing but with no snake oil theories.
I’m absolutely delighted with their KC62 sub. It’s a sub dedicated to music, not meant for home theater. It plays any bass with perfect definition and volume, rattling the whole room while having no vibration at all on its case.
I first tried with cheaper KEF KUBE 12B. It had massive bass but lacked definition. On strong bass, whole case would shook or slightly jump.
I’m absolutely delighted with their KC62 sub. It’s a sub dedicated to music, not meant for home theater. It plays any bass with perfect definition and volume, rattling the whole room while having no vibration at all on its case.
I first tried with cheaper KEF KUBE 12B. It had massive bass but lacked definition. On strong bass, whole case would shook or slightly jump.