jeffhenning
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- Mar 31, 2020
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Why would the crossover need to be lower?
There is nothing stating you can’t make a “musical” ported sub. In fact, most ported subs have less distortion. The SVS PB-12NSD as an example not only has far less distortion than the SB-12NSD, it also has quicker decay, so more musical all around.
Unless due to space constraints, after a certain price point, I see no reason not to choose a well design ported sub over a sealed one
The FV18 starts rolling off around 75-80HZ going up in frequency. The ideal crossover for the LS50 is around 170Hz. That big driver just can't make it that high.
As to ported designs having less distortion, that is only going to be around their port resonance. Somewhere below one octave above the port resonance, you will begin to get the benefit of the ported design. Above that, there is no benefit at all.
A ported sub can play louder, lower with less THD than a comparative sealed design around its port frequency, but you are aren't getting that for free. At the port resonance, the bass being produced is 360° out of phase with the upper octaves. As you get more output from the port, the more you hear that delayed bass signal. For an active sub, the phase response will be worse since there has to be a steep high pass filter to keep lower frequencies from causing the woofer to bottom out or being destroyed all together. Going down, ported designs unload the woofer of the back pressure caused by the cabinet and port. Any substantial signals below the port frequency can damage the driver.
You get more bass with less distortion on the bottom octave, but the cabinet is much larger and the temporal response is total crap.
Using a greater number of sealed subs, you get as ideal a temporal response as possible. The multiple subs increase headroom. Finally, multiple subs will allow you to place them in the room where they will produce the smoothest bass response in the listening area. One huge sub can't do that. It's in-room response will be compromised.
And, let's not forget, in both cases, we're talking about servo subs so "distortion" isn't really a very large factor for either unless you are talking about "Metallica" SPL's.
After getting them fairly dialed in, I've found my four L12's to be as good as any subs I've ever heard. They also produce a much cleaner low B from my 5 string than any bass amp.
A half dozen FV18's in a dance club would be incredibly potent and sound better than any PA subs on the market. If, on the other hand, you are looking for great bass in a room of 500 sq. ft. or smaller, four or six much smaller, sealed servo subs will give you everything you want and then some.
This is not my opinion. It's scientific fact that's been known for decades.