Woofer Column

[ackcheng]

My current system involved the following setup
Tweeter: RAAL
Mid: 18H AT C-quenze
Woofer: 8" AT Flex Units.

However, the current setup starts to roll off at the lower end from 35Hz. Inspired by Marten design, Marten - Coltrane Supreme

I would like to build a woofer column for the range 15Hz to 100Hz to cover the lowest octave. I understand that there are currently many subwoofer that can cover this range, but i am looking for something that gives fast, clean and dynamic bass to supplement my mains.

I am thinking of using 4 pcs of 10" AT sandwich on each side.
Sandwich cone

However, I am still thinking whether I should go for sealed or ported design. Based on calculation Fs/Qes, I should go for ported design. However, as I will be placing this woofer column next to the wall/corner of the room to make use of room gain, the port placement and tuning can be difficult. Also I have heard that closed box design with a low Q can give better impulse response and dynamics.

I will be running this woofer column active with DSP crossover, so I have enough power and tools with digital EQ.

Attached is the simulation of the ported and sealed design with a 200L box. Any suggestions?

[image]http://www.digitalroomcorrection.hk/...pedImage_1.jpg[/image]

[image]http://www.digitalroomcorrection.hk/...pedImage_2.jpg[/image]

[image]http://www.digitalroomcorrection.hk/...pedImage_3.jpg[/image]

[GM]

Best of both and better overall than either = some form of TL.

GM

[ackcheng]

TL is great but very hard to tune right, I imagine? Certainly out of my capacity.....

[GM]

Not once you learn the basics of 1/4, 1/2 WL tuned pipe theory, then use the available Excel spreadsheet to calculate different alignments to sim with his powerful/accurate/super inexpensive software and you too can become a TL designer of excellence without having to learn it all the hard way by trial & error like me and many others once did: Quarter Wavelength Loudspeaker Design

GM

[Arty]

try the :
Sub-Woofer Controller

suposedly it should be fast, and less hard to manage than a TL.

[David Gatti]

I prefer the sealed design myself. Much less group delay, a more natural sound (IMO) and the bottom end will get a significant lift and match well with a typical room. You might find you don't even need any EQ at all.

[Lusk]

For sealed design don't use standard 10" AT ask Per for specs. on driver to suit sealed enclosure for you.

[pkitt]

I'm sorry but I have to ask a question. What music, and I mean music, not noise or special effects, do you listen to that you believe you need a response to 15 Hz for? A big pipe organ is the only instrument I can think of that would possibly have any content that low in frequency, and even then, you wouldn't likely hear it, just feel it. There is extremely little content below even 40 Hz, much less below 30 Hz in music. Still, if you insist, I'm with GM--make it a TL.
Paul

[bbggg]

A very extended LF response may be important for piano lovers (some concert grands extend below 30 Hz), and it may also provide fringe benefits like low group delay or a subjective sense of large acoustic space. Obviously speaker design is an exercise in compromise, and the pursuit of some goals may confound other important parameters. One goal that is certainly futile is LF reproduction below a room's lowest resonance mode.

[ackcheng]

Thanks Guys,

Arty, your suggestion is very interesting. but I cannot find many example in the internet? I did some simulation and if I keep 4 drivers, I can pust the Fb to 75Hz.