Sealed Subwoofers are my Cup of Tea

[Paul McNeil]

I am using Dirac Live plus Bass Control running on a Marantz AV10. Previously, I had run in one corner of my room two SVS Ultra 13 cylinders, in the ported mode (lowest frequency configuration). These were supplemented with three Klipsch THX subwoofers stacked in the other corner. Because of all those corner and proximity effects, the cones were barely moving (for example, the SVS were adjusted down 35 dB). So, a restless 'Audioholic', I decided to try sealed. In went the foam plugs into all of the SVS's three ports. And foam into the slot loaded ducts of the Klipsch. Wow, do I like the sealed sound, though the overall frequency response measured by REW is not that different. I guess I have ears for time domain and ringing. One surprising thing, after many adjustments, was that the sub 20 htz response was improved. The sound for classical and acoustic jazz is to die for, everything else is fine too.
Here's the latest REW measurement. Any thoughts?

 

[ski2xblack]

Measurement looks great, particularly for subs placed in the corners. Kudos.

I don't know if I would chalk it up to your sensitivity to time domain and ringing. Maybe, maybe not. In good, capable ported designs, time domain issues occur so low as to not be much of an audible issue. We hear frequency and amplitude, mainly.

The arguments against sealed subs is generally that they are less efficient than ported for reproducing low frequencies, and require a brute-force approach regarding amp power secondary to huge boosts required for extended low frequency reproduction. Ported subs do have more phase shift as they roll off more steeply, and the fact that you have two different models with slightly different extensions might come into play there.

So keeping that in mind, lets see how it applies to your setup. You overcome the main objections to sealed subs via two distinct means. First, your five sub collection has the brute force by virtue of the sheer number of subs. With so many subs dividing the load, your setup must have gobs of available headroom and virtually zero modulation or drive level related distortion. They're all just loafing along, way down in their low-distortion zone of their safe operating areas. And second, your choice of corner placement and the rather dramatic boundary gain that entails, when combined with the slightly shallower roll-off of sealed alignment, allows them to extend in-room as deep as they do. The fact that the subs are stacked means slightly different locations for sources of low frequencies, so despite that they are all in corners of the room, it will result in more distributed modal excitation and smoother measurements.

So I think you essentially used a brute force approach to sidestep the limitations of sealed subs, while maybe benefiting slightly from their strengths in the time domain, to arrive at well measuring and subjectively satisfying results.

Being satisfied with the results, for maximum musical enjoyment, is the whole point of all this, after all. Time to boogie down to the music!!

Oh, and you must have a very forgiving wife.

 

[Paul McNeil]

Measurement looks great, particularly for subs placed in the corners. Kudos.

I don't know if I would chalk it up to your sensitivity to time domain and ringing. Maybe, maybe not. In good, capable ported designs, time domain issues occur so low as to not be much of an audible issue. We hear frequency and amplitude, mainly.

The arguments against sealed subs is generally that they are less efficient than ported for reproducing low frequencies, and require a brute-force approach regarding amp power secondary to huge boosts required for extended low frequency reproduction. Ported subs do have more phase shift as they roll off more steeply, and the fact that you have two different models with slightly different extensions might come into play there.

So keeping that in mind, lets see how it applies to your setup. You overcome the main objections to sealed subs via two distinct means. First, your five sub collection has the brute force by virtue of the sheer number of subs. With so many subs dividing the load, your setup must have gobs of available headroom and virtually zero modulation distortion. And second, your choice of corner placement and the rather dramatic boundary gain that entails, when combined with the slightly shallower roll-off of sealed alignment, allows them to extend in-room as deep as they do. The fact that the subs are stacked means slightly different locations for sources of low frequencies, so despite that they are all in corners of the room, it will result in more distributed modal excitation and smoother measurements.

So I think you essentially used a brute force approach to sidestep the limitations of sealed subs, while maybe benefiting slightly from their strengths in the time domain, to arrive at well measuring and subjectively satisfying results.

Being satisfied with the results, for maximum musical enjoyment, is the whole point of all this, after all. Time to boogie down to the music!!

Oh, and you must have a very forgiving wife.

You nailed that one, I do have a very forgiving wife!
And, I agree, I can use 'brute force', not only because of the corner locations but also because the subs (paired and tripled) proximity to each other (I think this is a 6 dB gain for the pair, who knows for the triple).
Of course, I may change my mind about the sound I'm hearing, as a restless audiophile, but am boogying now.
Thanks for your thoughtful and positive input.