Why does this subwoofer sound right?

It is very rare that a Subwoofer works well at my desk. I recently unloaded a Blue sky 2.1 system that I paid way too much for. Sealed woofers have not seemed to work even close up, I have tried all kinds of semi-cheap ported subwoofers(paradigm, klipsch etc.) and temporarily gave up while I focused on my 2 ways.
Pining for a bit of bottom end while reserving subwoofer funds for things like toroids, capacitors and resistors, I found this 10" downward firing Athena powered sub with no plate for $10.
I brought it home and instead of blocking off the plate, I put the amp cavity against the carpet, while facing the subwoofer forward thinking I may get a little faster bass but never imagined I'd get any depth.
To my surprise, It is hitting hard where my dyaudio 17w75s roll of and it is providing thunder at my desk. When I walk 10 feet away, I am expecting unbearable standing waves or an extreme bass neutral zone. Instead, the Sub bass leve increases very gradually and increases by only about 10% at the edges and corners of my room.
The subwoofer is 10". The enclosure has a 3" port coming out front and there is a smaller port facing upward to the underside of my desk. In as much as this setup is working well with the air in the room, it is not a fast, light and accurate driver and I would like to step up to something high end. I am just not prepared to start building enclosures and cutting holes in my desk until I am sure. I know I could easily spend $1000 on a driver and end up with an unsuitable configuration.
My ultimate desire would be to build an enclosure using the backboard of my desk as a baffle. The positioning would be in fair alignment with my 2 ways however I am far from certain what port configuration I would use in that position. Most ported subs I have listened to, have to be in strange locations to sound nice and work WITH my 2 ways. I am also concerned about my desk bandpassing my sound in the corners (maybe my knees will resolve that). If I could trust the potential for improvement, I'd cut my desk, Install a high quality sub in this box and shove it back away from my knees however I am wondering if the second port that is firing up at my desk is a WOULD BE flaw that is working to my advantage because it is 6 inches below the underside of my desk which is 2" thick hardwood.


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I think it's just because of the even dispersion. The desk could be seen as floating, since it has no direct contact with the floor (carpet), probably works like a port extension and diffusor of sorts. The upwards facing port (big fan of upwards port on BR, tried it first time in jan 2011.) does not couple as easily with the materials in the walls and floor (less vibration more sound), there are fewer obstacles in the ceiling.
It's possible that putting the open hole down on to the carpet does not completely seal it, but rather it acts like one of those variovents - an acoustic resistance that lets some air escape (in and out) of the box at low frequencies. I believe that this reduces the Q of the speaker. This might explain the different response that you perceive from the speaker - it IS different.


diyAudio Moderator R.I.P.
2005-11-24 1:47 am
could it come from 'accidental' better integration/synergy with your mains rolloff, and maybe result in better phase integration

actually, I have lately been thinking if my coming sub should just play the exact same bass frequency as my mains does on their own
just that, and not play any lower at all
or maybe just a little bit lower :clown::D