Suggestions for a 2-way Floorstander design

[kchilaka]

Folks,

I have some compact floor-standing cabinets that I would like to re-use for my first DIY project. I choose to go with an existing cab instead of building my own because I want to see what I can do with a DIY design before tooling up and buying wood for a full build. So right now, I have the empty cabs of an Infinity Reference 2000.5 that I plan to re-use. I have cut out the existing baffles and plan to use a new custom cut baffle.
Since I am re-using the cabs, I have to find a 2-way design that can work with the cab parameters. Which are

Interior Volume - 1.3 Cubic feet (About 35 litres)
It has a 12 inch long port (3 inches dia) which can be sealed if I wanted to.
Drivers - The new baffle width is 7.5 inches and I have about 12 inches to play with vertically.
Looks like I have two choices for a driver combo
1. 6.5 or 7 inch mid/bass driver and a simple dome tweeter
or
2. 6.5 or 7 inch subwoofer/dedicated woofer with a 2 inch full-range on the top.


So my question is, is there a well regarded two way design that can use about 35 litres of cab volume ? I am especially intrigued by the option of using a 2 inch full range on the top so I can get a dedicated subwoofer for the low-end. The original speakers had a low-end of 38hz at -3dB. I was hoping to better that by using a dedicated woofer and full range combo.
Here are what the cabs look like..

[picowallspeaker]

May I steal Sreten's (Diyaudio member ) bookmarks ? Many projects available on the net ,sure you'll find the one that fits.

undefinition
Zaph|Audio
FRD Consortium tools guide
RJB Audio Projects
Speaker Design Works
HTGuide Forum - A Guide to HTguide.com Completed Speaker Designs.
Humble Homemade Hifi
DIY Loudspeaker Projects Troels Gravesen

[kchilaka]

Originally Posted by picowallspeaker

May I steal Sreten's (Diyaudio member ) bookmarks ? Many projects available on the net ,sure you'll find the one that fits.

undefinition
Zaph|Audio
FRD Consortium tools guide
RJB Audio Projects
Speaker Design Works
HTGuide Forum - A Guide to HTguide.com Completed Speaker Designs.
Humble Homemade Hifi
DIY Loudspeaker Projects Troels Gravesen

Thats the mother lode of all reference links!. Thanks ! Any comments on using a small full range instead of a tweeter?

[picowallspeaker]

Thanks ,I'm fine .
A thread for Tysen and variations on FAST
Fullrange in 2-way....?

[kbgl]

Originally Posted by kchilaka

Thats the mother lode of all reference links!. Thanks ! Any comments on using a small full range instead of a tweeter?

The box size will pretty much limit how low it will play. I think one of the Peerless 6.5" HDS drivers may go as low as 40 hz F3 in that box. It would use a conventional tweeter, or a full range if that is your preference.

[kchilaka]

Originally Posted by kbgl

The box size will pretty much limit how low it will play. I think one of the Peerless 6.5" HDS drivers may go as low as 40 hz F3 in that box. It would use a conventional tweeter, or a full range if that is your preference.

I was looking at the Peerless 6.5 HDS drivers myself. There are quite a few 6-7 inch drivers with an Fs of 30 to 40 Hz. The 1.3 cu-ft volume, along with the port and the fact that the entire front face of the speaker below the baffle is a large aperiodic vent(Infinity calls it an acoustic filter) possibly means that the driver should be able to operate at close to Fs in this box. I am still not sure what kind of QTS I am looking for though. Because of the aperiodic vent and the large port I am thinking a low QTS (0.25 or so) should be appropriate. Power handling is not an issue as I will rarely be playing these above 85dB. Some of the drivers I found which have a really low Fs are..

Usher 8836A - 28 Hz - (0.26 QTS)
Madisound 6102-4 - 28.6 Hz - (0.26 QTS)
Adire Extremis - 30 Hz - (0.332 QTS)
Aurum Cantus AC-165 - 32 Hz - (0.37 QTS)
SB Acoustics SB17NRXC35-8-UC - 33 Hz - (0.33 QTS)
Peerless 831735 - 38 Hz - (0.43 QTS)
Tang Band W6-1139SI- 38 Hz - (0.4 QTS)

[kbgl]

Originally Posted by kchilaka

I was looking at the Peerless 6.5 HDS drivers myself. There are quite a few 6-7 inch drivers with an Fs of 30 to 40 Hz. The 1.3 cu-ft volume, along with the port and the fact that the entire front face of the speaker below the baffle is a large aperiodic vent(Infinity calls it an acoustic filter) possibly means that the driver should be able to operate at close to Fs in this box. I am still not sure what kind of QTS I am looking for though. Because of the aperiodic vent and the large port I am thinking a low QTS (0.25 or so) should be appropriate. Power handling is not an issue as I will rarely be playing these above 85dB. Some of the drivers I found which have a really low Fs are..

Usher 8836A - 28 Hz - (0.26 QTS)
Madisound 6102-4 - 28.6 Hz - (0.26 QTS)
Adire Extremis - 30 Hz - (0.332 QTS)
Aurum Cantus AC-165 - 32 Hz - (0.37 QTS)
SB Acoustics SB17NRXC35-8-UC - 33 Hz - (0.33 QTS)
Peerless 831735 - 38 Hz - (0.43 QTS)
Tang Band W6-1139SI- 38 Hz - (0.4 QTS)

The last two on your list will go low 40s. All the rest pretty much die above 50 hz, and the first two, above 60 hz. You do however have room for more than one driver. That "aperiodic vent" is not going to change the F3 for the better.

[kchilaka]

Originally Posted by kbgl

The last two on your list will go low 40s. All the rest pretty much die above 50 hz, and the first two, above 60 hz. You do however have room for more than one driver. That "aperiodic vent" is not going to change the F3 for the better.

Hm. Is it because of the lower QTS that the first two drivers will rollof at 60Hz or so? Unforunately that Tangband is a true subwoofer and rolls of at 800hz so I will need a full range on the top. Looking at higher QTS drivers, I came up with the following

Dayton DA175-8 (39 Hz Fs and 0.58 QTS) - This is pretty affordable.
Dayton RS180-4 (40Hz Fs and 0.5 QTS)
HiVi D6.8 (43 Hz Fs and 0.45 QTS)
GR Research M-165X (40 Hz Fs and 0.44 QTS)

As you pointed out, the peerless driver still seems a pretty good choice..