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Discussion Starter · #1 ·

Trying to get my hands on a decent sub for now and want to make dual subs later. Originally wanted to get the PB12-NSD (which were on sale here in Canada) but realized they are sold out and discontinued. My plan was to buy one now and one later since my research told me that they are just as good or better compared to a single PB12 Plus, which is sufficient to fill a 4000 cubic ft. room.

 

My problem now is that the only ones available to me are now the 300 watt PB-1000s or the 500 watt PB-2000s. The NSD was already kind of out of my price range but I was ready to swallow that cost. the PB-2000 at $889+tax is way over my $500 ballpark...

 

Since I am a speaker noobie, I could not find any information regarding mixing subs. It seems most people get identical subs when dual subbing but in some topics, I've read people using different subs as well without receiving any criticisms. 

 

So my question is, if I get a PB-1000 and later mix it with a PB-2000, is this going to cause a major issue? Do subwoofers need to match similar models? 

 

In the future, I want a dual sub system that is going to truly fill my room with soul trembling bass so I'd rather bite the bullet (and sell my headphones...) to get the PB-2000 if dual subbing it with a PB-1000 is out of the question. 

 

Thanks. And I apologize in advance if this question can be found elsewhere. I could not find a topic with a direct answer to this question. 
 

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The difference between a 300w and 500w sub running at full power is barely audible, if at all. IMO if your intent is to have two subs anyway get the 300w now and add another 300w later. It's counter-intuitive, but in terms of what you actually hear, which is decibels, two 300w subs are the equivalent of one 1200w sub. The only reason to go with the more expensive sub right off is if the less expensive sub doesn't go as low as you want and the more expensive sub does.

That said, chances are even two 12 inch loaded subs are not going to give you 'soul trembling bass', but that judgement has more to do with what your frame of reference is vis-a-vis 'soul trembling'.
 

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Bill,

 

  Would a dual 15" sub have an efficiency advantage over a similar size enclosure with one 12" or one 15"?  It seems to me(with my limited knowledge) that this would allow a lot of output with less power required, less driver excursion, lower distortion, less demand for an extremely high quality expensive driver etc etc.
 

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Quote:
Originally Posted by bear123  /t/1520540/does-power-disparity-matter-when-mixing-subs#post_24435073


Would a dual 15" sub have an efficiency advantage over a similar size enclosure with one 12" or one 15"?  
It would have less sensitivity. A driver requires a minimum amount of air volume in the cab to work properly at low frequencies.
 

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Discussion Starter · #5 ·

Well I finally picked up a subwoofer and went with the PC12-NSD. Qutie impressed by the amount of power it can produce alone. I can definitely feel the entire room shaking in the trainwreck scene during Super 8 (please recommend great scenes to stress your sub!). This is a huge upgrade from the wharfedale SPC10 I recently got rid of, I've definitely never had bass like this before and am super satisfied with the quality and the sheer output, especially after running two whole albums through it.


However, I know I still want more... (am I considered bass head?). I've since found a seller for a PB12 NSD for a very good price but is it ok to have a cylinder and a box sub? After scouring these forums, I've found people saying that you either need the same subs or subs that are very similar. You can't get more "similar" without being the same in this situation so I am assuming that this is a safe mixture? 

 

 

Also, can anyone explain if dual subs or a single stronger sub is better for pressurizing a room? From this forum, I understand that pressurization comes with greater decibels at certain points below 40hz (since my room is 28 ft. long). So I wonder how dual subs scale in terms of being able to provide higher decibels for lower frequencies. If a single NSD can produce 100 decibels at 20hz, what will having two subs be able to give me?
 

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+6 dB for duals.  Proper placement is necessary to realize the full 6 dB at the MLP.
 

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Quote:
Originally Posted by bear123  /t/1520540/does-power-disparity-matter-when-mixing-subs#post_24436915


+6 dB for duals.  Proper placement is necessary to realize the full 6 dB at the MLP.
Getting 6dB equally across the full pass band requires that they be mutually coupled, ie., placed less than 1/4 wavelength apart. With an 80Hz crossover that's 3.5 feet. But the main benefit of multiple subs isn't output, it's smoothing of room response. That's usually best achieved by separating the subs as far as possible. Being sure of where the second sub gives the best result demands having measuring software, without it you can't really know what's going on.
 

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Discussion Starter · #8 ·

Thats very informative. Basically, those are two opposite goals. But I am assuming I would still get a large increase even if I have them like 12' apart?
 

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You can get 6 DB gain in theory. They basically have to be in the exact same spot in perfect phase with each other to get a 6 DB gain. Which is impossible. If they're really close, you can get close to a 6 DB gain. In practice, subs spaced far apart will yield between a 3 and 5 db gain since they'll partially cancel each other out.


As far as identical subs goes. In most cases, it's better to have matching subs, but not always. You can take a sub and place it in 2 different spots in a room and hear different results, so having 2 physically identical subs doesn't mean they'll be logically identical. If they sound different, then for all intents and purposes, they are different. In many cases, you can do just as well with non matching subs as with matching. I would suggest at a minimum that the subs have similar capabilities. I.e If sub A can play 100 db at 20 Hz, sub B should be able to play at least 97 db at 20 Hz.
 

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Quote:
Originally Posted by DNZone  /t/1520540/does-power-disparity-matter-when-mixing-subs#post_24438390


Thats very informative. Basically, those are two opposite goals. But I am assuming I would still get a large increase even if I have them like 12' apart?
You'll still get the full 6dB at most frequencies. Where you won't is where the waves from the subs, and the reflections of those waves off the room boundaries, meet at or close to 180 degrees out of phase. There's a few frequencies where that will happen, but a lot more where it won't. There will even be a few frequencies where you'll get zero gain, even negative gain, but not many. What matters is that the overall result will be louder, and much more uniform.
 

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Discussion Starter · #11 ·

Performance wise, I'm pretty sure the PC and PB NSD are nearly identical so I guess I will be fine on that. The uniformity issue seems a little complicated and I have no idea how I can tell if its setup properly. If the issue is so serious, I wonder if I am losing a lot of sound right now just by virtue of being in a select listening position. I'm definitely going for dual subs though so I guess I will just have to try this out and see for myself.
 

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Quote:
Originally Posted by DNZone  /t/1520540/does-power-disparity-matter-when-mixing-subs#post_24438722


I have no idea how I can tell if its setup properly.
Measuring software. The necessary hardware is cheap, the software is free. Google REW.
 
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