I have a pair of RSS390HF-4 drivers. People seem to like the way these drivers sound in both sealed and ported applications.
Sometimes I want to use them as part of my music studio -- so the idea of putting them in a sealed box with a bessel tuning of Qtc=0.577 for nice transient response is tempting. That would be a box size of around 250-280 liters (9-10ft^3). I have never actually listened to sealed subs with a bessel tuning before, so I don't know if I would actually like that. But, on paper, good transient response sounds desirable for a studio monitor system.
Sometimes I'd like to use them for movies or backyard dance parties -- so it would be tempting to put them in a ported box for that extra low end extension and SPL. It looks like a good box size for that is also around 250-280 liters.
Can I have my cake and eat it too? Can I build a 250-280 liter ported box and then just plug up the ports when I want to favor SQ over SPL? Or is that a gimmick that doesn't work in practice?
I know the RSS390HF-4 is often used in smaller 3-4ft^3 sealed boxes -- which seem undersized to me. Does it sound bad in larger 6-9ft^3 sealed boxes? I know that without filtering I gotta keep the volume knob low because 20Hz @ 150W is enough to exceed Xmax. And at 14Hz, 100W is enough.
When I really want to annoy the neighbors, I have a pair of Cubo 18 subs. So I am more interested in a sealed box than a ported box for this build. But if I can have it both ways.. then why not?
Sometimes I want to use them as part of my music studio -- so the idea of putting them in a sealed box with a bessel tuning of Qtc=0.577 for nice transient response is tempting. That would be a box size of around 250-280 liters (9-10ft^3). I have never actually listened to sealed subs with a bessel tuning before, so I don't know if I would actually like that. But, on paper, good transient response sounds desirable for a studio monitor system.
Sometimes I'd like to use them for movies or backyard dance parties -- so it would be tempting to put them in a ported box for that extra low end extension and SPL. It looks like a good box size for that is also around 250-280 liters.
Can I have my cake and eat it too? Can I build a 250-280 liter ported box and then just plug up the ports when I want to favor SQ over SPL? Or is that a gimmick that doesn't work in practice?
I know the RSS390HF-4 is often used in smaller 3-4ft^3 sealed boxes -- which seem undersized to me. Does it sound bad in larger 6-9ft^3 sealed boxes? I know that without filtering I gotta keep the volume knob low because 20Hz @ 150W is enough to exceed Xmax. And at 14Hz, 100W is enough.
When I really want to annoy the neighbors, I have a pair of Cubo 18 subs. So I am more interested in a sealed box than a ported box for this build. But if I can have it both ways.. then why not?
KEF includes port restrictors and plugs for some models to give bass tuning options. As long as the woofer performs satisfactorily in either configuration, it's a reasonable thing to try.
Far from ideal in most cases. Your plugged port version of sealed box going to sound sloppy compared to optimum sealed one. Also you will loose some power handling and spl in upper band. Power/spl loss may or may not be a problem based on your room gain and crossover point.
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qtc .577 is over rated, but give it a try. I have had good luck qtc .7- .9, higher qtc more accurately follows the input response.
file:///Users/dd/Downloads/Box-Q-1.pdf
file:///Users/dd/Downloads/Box-Q-1.pdf
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Some notes:
- When using subwoofers in an acoustically-small space, DSP-based EQ is basically mandatory. Given that, I wouldn't worry too much about the size of the sealed box. So long as you can make use of the driver's excursion with your chosen amplifier, you'll be fine.
- Building a ported box, and then blocking the ports when necessary, is perfectly reasonable. I did similar with some PA speakers. 70Hz tuning for more output when running with subwoofers, 44Hz tuning for without subwoofers. Those cabs are still in use, and they sound great either way.
- Since you already have the Cubo18 subs, I'd think carefully about the use cases, and whether your proposed cabinet will be usefully smaller than the Cubos. If they end up bigger/heavier, then you'll probably just want to use the Cubo subs anyway.
Perhaps it would be better to put the Daytons in smaller sealed boxes. Use them outdoors for lower SPL stuff, and the Cubos for the big parties.
Chris
- When using subwoofers in an acoustically-small space, DSP-based EQ is basically mandatory. Given that, I wouldn't worry too much about the size of the sealed box. So long as you can make use of the driver's excursion with your chosen amplifier, you'll be fine.
- Building a ported box, and then blocking the ports when necessary, is perfectly reasonable. I did similar with some PA speakers. 70Hz tuning for more output when running with subwoofers, 44Hz tuning for without subwoofers. Those cabs are still in use, and they sound great either way.
- Since you already have the Cubo18 subs, I'd think carefully about the use cases, and whether your proposed cabinet will be usefully smaller than the Cubos. If they end up bigger/heavier, then you'll probably just want to use the Cubo subs anyway.
Perhaps it would be better to put the Daytons in smaller sealed boxes. Use them outdoors for lower SPL stuff, and the Cubos for the big parties.
Chris
