Hi Bjorn,
Thank you for running the simulations of my design. Wow - 38 Hz! I never would have guessed it could get that low. So for the driver I am thinking of using, there is no benefit of having the long path as it is mismatched with the driver's Fs, no matter how big the Qts is? This however, raises some interesting possibilities for a fairly compact cabinet for a driver with a lower Fs of 60 Hz and deeper Xmax? You are right that this is fun, I have Mathcad Professional and use it for modeling everything at work but do not have the MJK worksheets. So going back to the TABAQUBE design will preserve the circa 30 in pathlength. If I go with a 32 inch long TABAQ, and force the last section to be 6 inches long, would the cross section still be 1 Sd?
Thanks again.
Regards,
xrk971
Thank you for running the simulations of my design. Wow - 38 Hz! I never would have guessed it could get that low. So for the driver I am thinking of using, there is no benefit of having the long path as it is mismatched with the driver's Fs, no matter how big the Qts is? This however, raises some interesting possibilities for a fairly compact cabinet for a driver with a lower Fs of 60 Hz and deeper Xmax? You are right that this is fun, I have Mathcad Professional and use it for modeling everything at work but do not have the MJK worksheets. So going back to the TABAQUBE design will preserve the circa 30 in pathlength. If I go with a 32 inch long TABAQ, and force the last section to be 6 inches long, would the cross section still be 1 Sd?
Thanks again.
Regards,
xrk971
Hi xrk971
My suggestion with TB Driver and a pipe of 32 + 6 inches:
The first 32" are 4 Sd and the last 6" 1Sd.
0.217 lb stuffing in the upper 2 / 3.
Stuffing is something you can experiement with, but this should be a good startinh point
The tuning frequency is about 58 Hz, and work for this driver as it has a hight Qts.
Hi from Bjorn
My suggestion with TB Driver and a pipe of 32 + 6 inches:
The first 32" are 4 Sd and the last 6" 1Sd.
0.217 lb stuffing in the upper 2 / 3.
Stuffing is something you can experiement with, but this should be a good startinh point
The tuning frequency is about 58 Hz, and work for this driver as it has a hight Qts.
Hi from Bjorn
If I made the cross sectional area only 4 in x 4 in (3.2 Sd) would that affect the performance greatly? This would make a much more compact cube shape cabinet rather than rectangular shaped. I will still keep 32 in plus 6 in exit section.
Thanks,
Xrk971
Thanks,
Xrk971
I have to simulate, but are "on tour" this week. I assume it will work fine, maybe some adjustments of the stuffing. Please note that the sim is with internal dimensions.
By the way, why not purchase the models from MJK, it is not as difficult to use at it might look the first time you open the spreadsheet.
By the way, why not purchase the models from MJK, it is not as difficult to use at it might look the first time you open the spreadsheet.
How exactly are the internal divisions shaped and placed? I find it hard to imagine from your description.
Here is a see-thru version. There are three internal dividers: one shaped like an 'L' and two shaped like small rectangles placed perpendicularly to the 'L' divider to direct the path starting from the closed end (the quadrant in front to the right of the speaker hole, above the vent), the path goes up, then turns 90 left, 90 degrees down (past speaker) then turns 90 degrees towards back wall, through the opening in the 'L' and 90 degrees up, then 90 degrees right, then 90 degrees down, where it reaches the final quadrant in the back, from here it turns 90 deg toward the front and exits through the rectangular port on the front. The port has a top wall that also serves as the closed-end wall. The total path not including the vent is 32 inches. Stuffing would be placed basically in the first 2 quadrants and partially in the third quadrant to fill about to 2/3 as Bjorn suggests - although this can be tuned. The speaker is located at about 1/3 of the way from the closed end. I would make the top lid removable with screws and gasket so that one can play with tuning using stuffing. This design permits the TABAQ to be essentially a bookshelf or desktop style speaker for a PC. The terminus being located at the front will enhance the bass and may reduce the amount of BSC.
Attachments
Ok, just as I thought at first. But isn't the port too long if you are using the whole depth of the path?
Very good idea though (although I'm sure that basic idea is not new).
The wider baffle will probably also help WRT BSC.
Very good idea though (although I'm sure that basic idea is not new).
The wider baffle will probably also help WRT BSC.
hi, I'm new here, is it ok to have TABAQ box slightly slanted backward instead of the usual straight up?, just curious for aesthetic reason
thanks
thanks
I see no reason why not. Indeed it's a good idea if you plan on putting it on the floor because more of the HF lobe of the driver will be directed at ear hight instead of reflecting/being absorbed in the floor.
The only slight problem could be that the port doesn't get as much floor loading.
You might put the port on the front of the bottom to compensate though, but that would call for a good amount of tilt (at least get the port 4 or 5 cm of the floor to not affect the tuning).
The only slight problem could be that the port doesn't get as much floor loading.
You might put the port on the front of the bottom to compensate though, but that would call for a good amount of tilt (at least get the port 4 or 5 cm of the floor to not affect the tuning).
Squeak,
The port length required the area to be adjusted. Bjohanessen did the simulation and said to keep the port cross sectional area the same as the driver area for the longer port length. Hence the opening is 4 inch wide x 1.25 inch tall.
Xrk971
The port length required the area to be adjusted. Bjohanessen did the simulation and said to keep the port cross sectional area the same as the driver area for the longer port length. Hence the opening is 4 inch wide x 1.25 inch tall.
Xrk971
on the posn of the port: I would advise anyone to avoid a port on the front for full range (or 2 way) because of the midrange output that will be there (incl port resonances). I had a BR with an Alpair6 with the port on the front, and imaging was not as I expected, putting some damping in front of the port did solve that
Ide2003,
Are you asking if the Tabaqube can be slanted? It could but construction would not be simple 90 degree corners anymore. Acoustically, if you follow design guidelines of keeping cross section and path length, driver location and venting cross section and length it should all work. Angling straight Tabaq does aim sound up from rather low position if they are on floor.
Regards,
Xrk971
Are you asking if the Tabaqube can be slanted? It could but construction would not be simple 90 degree corners anymore. Acoustically, if you follow design guidelines of keeping cross section and path length, driver location and venting cross section and length it should all work. Angling straight Tabaq does aim sound up from rather low position if they are on floor.
Regards,
Xrk971
hi Xrk971, not the tabaqube, only the tabaq, my plan is to use slanted tabaq on the sides of PC desk , I will continue with version B then, thank you
I went back and reviewed older posts and noticed that Bjohanessen had simulated the Vifa TG9FD (fiber glass cone) driver with great results. I had been looking at the Vifa TC9FD (paper cone) which actually goes to 20 kHz compared to the TG which is not as high. They both have same Qts and rather substantial Xmax (2.55 mm). I think this may actually be better than the 3 in Tang Bands and they only cost $12. Would the larger xmax here compared to the TBs improve the bass response? This driver seems to be a little noticed gem. Does anyone have experience with it?
I tried a similar Vifa (white, glassfibre, TG9FD-10-04) some time ago in a Needle, and was impressed, a very good driver, better low and high than the W3-871 (back then the price was $50 and imho worth it)
An externally hosted image should be here but it was not working when we last tested it.
The Vifa TG9FD is imo a great little gem! I use it in a flat/wall speaker (tml). Great neutral midrange, decent amount of high freq on axis and bass in the tml is good. For the price unbelieable value!!! So go and try them.
Vifa TG9FD tml build thread
Vifa TG9FD tml build thread
I just ordered two from Parts Express. Looking forward to hearing them in the Tabaq. Thanks for feedback. Will BSC circuit need to be changed compared to TBs?
Sayrum,
My inability to read German was solved by google translate and I am glad I saw your thread on the wall speaker - very clever design and the ability to turn into a painting is perfect for my kid's room, and it has a very high WAF! I like the fact that it can be made with just a small handsaw for cutting pine strips.
Thanks for the link.
Regards,
xrk971
My inability to read German was solved by google translate and I am glad I saw your thread on the wall speaker - very clever design and the ability to turn into a painting is perfect for my kid's room, and it has a very high WAF! I like the fact that it can be made with just a small handsaw for cutting pine strips.
Thanks for the link.
Regards,
xrk971