Ah, now that's where the problem is...the two dimensions are completely different, as you yourself point out. One is the line length, and one is the cabinet internal height.
What you need to understand is that cabinets of many different heights, and shapes, and foldings, can be built, all with the same line length. For example, the one that I built, the drawing for which I attached to an earlier post, has an internal height of around 392mm, but still achieves a line length of 762mm, since I folded the line.
On the last page of the drawing from post 2511 which you refer to, that I have attached again here, it does indeed show the height of the piece of wood forming the side of the as 79cm, or 790mm, but this has changed from other drawings because it is drawn for a different material thickness. But you are simply confusing yourself by looking at those dimensions and comparing them to the line length. The only thing you should be looking at to know the line length is the "TABAQ Geometry" section on the third page. These are the critical dimensions, that Bjorn has then, on the last page, and elsewhere, worked into a number of cabinet designs that can actually be made. And if you look at the side view on the left in the drawing on the last page, you will see the line length defined. Take the 55.9mm dimension from what is the end of the line in that cabinet design to the centre of the driver position, add it to the 20.3mm dimension from the centre of the driver position to the underside of the top, and you have 76.2cm!
Can I suggest that you let everyone here know what driver you plan to use in your build, and the form factor you are interested in, and then someone might point you to which of the variants you might build, and possibly even to a set of plans (with many dimensions not necessarily connected to the line length!) that will work well...
Hi Pugwash,
You are right I gone all over the history of this thread and realise the mistake, in few word what now is right is the TABAQ UPDATE 2 that is dated at the end of page 4 "March 3rd 2017", in this update you have two models the first with the shorter port and the second on page 4 the modification of the Tabaq Original, so the 790mm are the right one, here all the history on the forum so you can also check by yourself:
#1364 Robskillz point out the problem
#1366 Bjorn confirm the mistake
#1369 Ref.R2 is accepted as the right design
#1686 Bjorn reconfirm
#2018 Bjorn post the TABAQ UPDATE 2 drawing
Now as Luigiman suggest pick your driver and see then what is the most suitable Tabaq for it.......all the best
Thanks both, yes, speaking only of the floorstanding design, it makes sense that "TABAQ UPDATE 2' is the latest version, however that document itself is a little misleading as the last drawing with the newer internal column height of 790mm still has the older port design. Out of interest also I did not read any justification for change from 808mm internal height to 790mm (its not as Luigiman suggests a change in material thickness as all Bjorn's documents use 12mm).
I have a pair of 8ohm Faital Pro 4FE32 which I plan to use. I have read that these work in the original design (I take that to be document "TABAQ TL for TB4") with the 808mm internal height) but that might be old news. I also see in my notes a mention of increasing cross section for 4" drivers to 154cm squared but couldn't find why.
I have a pair of 8ohm Faital Pro 4FE32 which I plan to use. I have read that these work in the original design (I take that to be document "TABAQ TL for TB4") with the 808mm internal height) but that might be old news. I also see in my notes a mention of increasing cross section for 4" drivers to 154cm squared but couldn't find why.
The increses cross section for the 4" drivers will give you a better bass. "More volume = more output from the port".
When I mounted the 4" driver in the orginal TABAQ, I (and others) found there was a small drop around 80 Hz, making the bass a little weak. By reducing the stuffing it is possible to cempensate for this, but the best solution was to increase the volume a little (increasing the cross section)
Hi
Bjørn
When I mounted the 4" driver in the orginal TABAQ, I (and others) found there was a small drop around 80 Hz, making the bass a little weak. By reducing the stuffing it is possible to cempensate for this, but the best solution was to increase the volume a little (increasing the cross section)
Hi
Bjørn
Apologies, pugwash, I was wrong about that. The "TABAQ Update 2" document is a little confusing, since the drawing on page 2, done by robskillz I believe, actually has a line length of 78mm (52mm+26mm), which to my mind is incorrect, though Bjorn can confirm.
+1
I agree that the internal height (203+559 = 762mm) is not correct on that plan. According to me this internal height should still be the same as the original 780mm. Even more so, this plan with the longer port is best suited for 4" drivers and should actually be changed to increase the volume slightly by a bigger cross sectional area as Bjorn suggests in #2824. Would be great if someone can give an indication by how much bigger?
PS: looks like we all posted at the same time.
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Yes, I could be using wrong terminology here. From what I see when working with speaker dimensions is that in most cases one works with the internal volume parameters, as the outside dimensions depends on material thickness. In this case Bjorn always worked with 12mm.
Don't know if I am using the correct terminology, but if we consider the internal volume of the original TABAQ plan – it is 780 (H) x 100 (W) x 128 (D) mm, with a port length of 130mm. Then robskillz suggested a slighter shorter port length of 97mm, but I don’t think the other dimensions were supposed to change – only a shorter port length for 3” drivers. If I understand correctly – for 4” drivers the original TABA.Q plan’s dimensions is still best, however Bjorn suggests that the internal volume can be increased slightly too. Not smaller by reducing the internal volume height, as indicated on the plan on page 4 of TABAQ UPDATE 2.
Also Captain, not to confuse matters further but to make another recommendation is to consider Plan B in post #1651, but adjust the measurements to increase the port length to 130mm. The reason why I like this plan best, is it makes the TABAQ slightly taller to bring the driver closer to ear level, as well as creating a nice cavity in the enclosure which I fill with sand (in a sealed plastic bag) to give more weight to the bottom of the speaker. It does not topple over so easy.
I would say the original internal volume was 808mm (H) x 100 (W) x 128 (D) mm, meaning the internal height from top to bottom was 808mm not 780mm. The 780mm was the original line length. Knowing that the modelling gives a 30 inch (762mm) line length, it was these initial dimensions plus subsequent changes to drawings that didn't include all updates to port, driver position and line length all in the same drawing that initially got me confused.
I was seeking clarity obviously for my own build but also, as a fresh pair of eyes to this great thread, attempting to consolidate the various iterations the design has had over the years. A picture paints a thousand words...but only if its the right picture!!
Dimensions and comments
The correct internal lenght for the TABAQ is 30" + 3.8"
In mm: 762 and then 97 mm for the port.
robskillz pointed out that the physical dimension in my drawing was not 97 mm, this was an "error" I made more than 10 years ago just to make the construction simpler
For the 4" version the line lenght is the same, it is the cross section of the line that has been increased (larger volume).
Please note: The driver should be 8" from the closed end, not 10" as shown in the original paper.
There are different ways to make the port, as long as the dimensions are the same. Sandfilling the bottom is a very good idea.
Take a look at a test I made for an alternate port.
/Bjørn
The correct internal lenght for the TABAQ is 30" + 3.8"
In mm: 762 and then 97 mm for the port.
robskillz pointed out that the physical dimension in my drawing was not 97 mm, this was an "error" I made more than 10 years ago just to make the construction simpler
For the 4" version the line lenght is the same, it is the cross section of the line that has been increased (larger volume).
Please note: The driver should be 8" from the closed end, not 10" as shown in the original paper.
There are different ways to make the port, as long as the dimensions are the same. Sandfilling the bottom is a very good idea.
Take a look at a test I made for an alternate port.
/Bjørn
Attachments
The size that matter is the internal volume that is pointed by the two red arrow ( 26+52=78cm), then from the blue arrow start the port.
Attachments
@Bjorn - thank you for clarifying. Confusion wants to reign here today. It would be fantastic if you can sim the 4FE32 drivers please. I think many here would be interested, myself included as I have a pair waiting. I just completed drawing the dxf files for CNC cutting, until the Captain came and confused us all.
@kissabout2002 – please don’t make things longer than they should be. If you calculate like Bjorn above, it is should be:
1.2 + 9 + 0.8 + 0.8 + 1.2 = 13cm = 130mm
@kissabout2002 –
please don’t make things longer than they should be. If you calculate like Bjorn above, it is should be:1.2 + 9 + 0.8 + 0.8 + 1.2 = 13cm = 130mm