Subwoofers

[steveh]

I have searched the forum and can't seem to find the information that I am looking for. I have two 2245's not in use and am considering building a pair of subs. I would like to base them on the August 1983 article in Audio Magazine, by Lorr Kramer and Greg Timbers. More specifically I am interested in the 12 cubic foot version with outside diminsions of 44" X 29" X 21" (using 3/4" mdf). My intent is to use 1" material instead of the 3/4". In the article, their project was constructed as a "lo boy" design. I would like to build an upright version. Has anyone built these and if so, what are your opinions, what kind of amplifiers have been used on them? Any thoughts, suggestions or advice would be appreciated. Any pitfalls to consider when using two subs instead of one :blink: ?

Thanks,
Steve

[loach71]

I built the 12 cubic foot Timbers enclosures (four of them). I up sized the dimensions based upon the following:

I used 13 ply Baltic birch plywood as the outside wall (.75" thick) and then braced all the joints internally with jointed and planed spruce wood (1.5" x 3"). Once this was done, I lined the internal exposed faces of the birch plywood with MDF (.75" thick). The front baffle was made with two layers of the Baltic birch plywood.

Modeling the Timbers 12 cu foot box with my lining and the bracing, the length, width and height of the box came out to be approximately 1" larger than the dimensions in the Timbers article. I left the layout the same as in the Timbers article as it facilitates the use of the approximately 30" long vent pipe without bends. I use Neutrik SPEAKON connectors for the signal cable connections. I'm just in the process of applying the teak corner inlays, teak veneer and lacquer.

I use two BGW 750-D power amps crossed over at 18 Hz and 80 Hz (4th order) to power the subs - one channel per 2245H driver. You want TONS of clean power for superb reproduction of Dolby Digital or DTS tracks - don't skimp on this! The bass from these drivers and enclosures is prodigious. I am finally pleased with my system's delivery of the "bottom octaves".

[northwood]

I built the 12 cubic foot Timbers enclosures (four of them). I up sized the dimensions based upon the following:

I used 13 ply Baltic birch plywood as the outside wall (.75" thick) and then braced all the joints internally with jointed and planed spruce wood (1.5" x 3"). Once this was done, I lined the internal exposed faces of the birch plywood with MDF (.75" thick). The front baffle was made with two layers of the Baltic birch plywood.

Modeling the Timbers 12 cu foot box with my lining and the bracing, the length, width and height of the box came out to be approximately 1" larger than the dimensions in the Timbers article. I left the layout the same as in the Timbers article as it facilitates the use of the approximately 30" long vent pipe without bends. I use Neutrik SPEAKON connectors for the signal cable connections. I'm just in the process of applying the teak corner inlays, teak veneer and lacquer.

I use two BGW 750-D power amps crossed over at 18 Hz and 80 Hz (4th order) to power the subs - one channel per 2245H driver. You want TONS of clean power for superb reproduction of Dolby Digital or DTS tracks - don't skimp on this! The bass from these drivers and enclosures is prodigious. I am finally pleased with my system's deliver of the "bottom octaves".

:useless:

[loach71]

Agreed - I'll post pictures as soon as my digi cam is returned from warranty repairs.

[steveh]

Hi Loach 71,
Thank you for your responce. Nice to hear that someone else is familiar with the article referenced. I would have thought that more forum members would have had experience with this design, I guess not. Thanks again, I look forward to your photos.

Northwood, when oil reaches $100 a barrel, we will all be on the same playing field. I spent considerable time in China and emphathize with you. Just remember, we are all in this together regardless of what the politicians tell us.

Best Regards,
Steve