planet10 said:
Can you post some more pictures?
dave
Dave,
I will post pictures as soon as I am finished with the base, right now it is just sitting on a 1.75" piece of lumber which is not even optimal since it is blocking the opening front and back. I ordered some spikes and it has not arrived yet.
Thanks for your plan, I really appreciate your generosity and the detailed plan.
fred76 said:Nice work Alex...yep, more pics pls.
Fred,
I will post pix as soon as I get the spikes I ordered (http://www.viablue.de/com/spikes_hs.shtml) and after I have applied the varnish.
BTW, my friends and I are invited to the Alabang Hi-Fi Show (Alabang, Philippines) and there will be a DIY area, we might feature my iBIBk build, my SE KT88 as designed by Mikael of diyAudio.com and my 7193 preamp. The show will be sometime in July, I will let you know and if you have any DIY that you want to show I can coordinate with the event coordinator.
I will be experimenting with a -3db BSC circuit for this speaker, though I love the vocals and highs, the speaker is a bit shouty, so I will try a 1mH air core inductor paralleled with a 3R3 resistor. After the 127e break-in, then I will try the speakers without the BSC. Later, I will also try a supra baffle.
Since I cannot build a supra baffle yet and I have a 1mH and a 3R3 resistor, I soldered a baffle correction together and installed it on my iBIBk, what a difference! Less shouty and better tonal balance, even the soundstage is better.
I plan to remove it when the 127e are broken in and if I had the chance of adding a supra baffle.
I plan to remove it when the 127e are broken in and if I had the chance of adding a supra baffle.
Just a thought..
Has anyone thought about putting another FE126E driver on the top/back at a 45 degree angle like the BD-Pipe?
http://www.t-linespeakers.org/FALL/bd-pipes.html
Double the power handling, 96db efficiency!
Could this be modeled, perhaps? It might suck, but it might not...
(edit, typo)
Has anyone thought about putting another FE126E driver on the top/back at a 45 degree angle like the BD-Pipe?
http://www.t-linespeakers.org/FALL/bd-pipes.html
Double the power handling, 96db efficiency!
Could this be modeled, perhaps? It might suck, but it might not...
(edit, typo)
Most of those don't exist in-room, especially over 275Hz or so, and using the ~ 0.416 position eliminates most of those in a 1/2 space response too.
There's no might or just about it: 2 drivers can potentially smooth a response out with some creative positioning in the line, although juggling these positions is tricky. Usually easier is to provide each driver with an independant line, one tuned 1/2 an octave or so above the other creating a relatively smooth summed response. Hm does this with his bipole cabinets, which are QWRs with a variation on hyperbolic rather than linear expansion.
There's no might or just about it: 2 drivers can potentially smooth a response out with some creative positioning in the line, although juggling these positions is tricky. Usually easier is to provide each driver with an independant line, one tuned 1/2 an octave or so above the other creating a relatively smooth summed response. Hm does this with his bipole cabinets, which are QWRs with a variation on hyperbolic rather than linear expansion.
2 way iBIB(k)
I just completed a two way iBIB. The cab stands at 77 inches in height, the internal length is 72.50 inches (total line length being 145 inches), Sm=58.50 and Zdriver is 33 inches. The iBIB is loaded with a 6.5" mid-bass driver and a dome tweeter. The dims were graciously given to me by Scott after I had furnished the parameters of the driver.
I have cut slots in the front, rear and one side of the cab, the area almost exactly equalling Sm. The cab is thereby lifted 4 inches of the floor.
The one side which is now meeting the floor is reserved for the k-slot.
Though I have completed 2 cabs, I have only one cab loaded with the drivers for intial testing. The inside of the top panel has two layers of 1 inch thick dacron. The drivers are mounted on a supra baffle which is 17" x 14" (H x W), which I plan to finally trim into an ellipse.
My observations are as follows: The amount of bass is lacking compared to a much shorter Quarter Wave Pipe loaded with the same drivers. The loss of bass is significant in front of the speakers and towards the side which has the slot cut. However, while listening from the side reserved for the k-slot, which is now meeting the floor, I hear the lower registers of bass quite strongly.
For whatever bass I am hearing right now, I should say that it is very clean as compared to the other pipe referred to. The mid-bass is excellent, low level detailing and resolution are fantastic.
I tried to invert the box as a normal BIB and found that just about adequate levels of bass is obtained only when corner loaded.
I want to try the k-slot, but is this what is expected of an iBIB without the k-slot and a normal BIB??
The driver's Fs is 37Hz (quoting from memory and I could be wrong) and its Xmax is 5mm. The in-room bass obtained with this driver in the QWL pipe is very strong and astonishing, probably down to 30Hz or so.
What could be wrong and what should I check for?
I just completed a two way iBIB. The cab stands at 77 inches in height, the internal length is 72.50 inches (total line length being 145 inches), Sm=58.50 and Zdriver is 33 inches. The iBIB is loaded with a 6.5" mid-bass driver and a dome tweeter. The dims were graciously given to me by Scott after I had furnished the parameters of the driver.
I have cut slots in the front, rear and one side of the cab, the area almost exactly equalling Sm. The cab is thereby lifted 4 inches of the floor.
The one side which is now meeting the floor is reserved for the k-slot.
Though I have completed 2 cabs, I have only one cab loaded with the drivers for intial testing. The inside of the top panel has two layers of 1 inch thick dacron. The drivers are mounted on a supra baffle which is 17" x 14" (H x W), which I plan to finally trim into an ellipse.
My observations are as follows: The amount of bass is lacking compared to a much shorter Quarter Wave Pipe loaded with the same drivers. The loss of bass is significant in front of the speakers and towards the side which has the slot cut. However, while listening from the side reserved for the k-slot, which is now meeting the floor, I hear the lower registers of bass quite strongly.
For whatever bass I am hearing right now, I should say that it is very clean as compared to the other pipe referred to. The mid-bass is excellent, low level detailing and resolution are fantastic.
I tried to invert the box as a normal BIB and found that just about adequate levels of bass is obtained only when corner loaded.
I want to try the k-slot, but is this what is expected of an iBIB without the k-slot and a normal BIB??
The driver's Fs is 37Hz (quoting from memory and I could be wrong) and its Xmax is 5mm. The in-room bass obtained with this driver in the QWL pipe is very strong and astonishing, probably down to 30Hz or so.
What could be wrong and what should I check for?
Here is a picture showing both the QWL speakers and the iBIB(k) cabs. I am writing the 'k' within parenthesis because it is not yet calculated or cut. The side facing away from the camera is where the k slot is intended to be cut. (Please don't mind the surrounding stuff which I didn't bother the clear before taking this quick shot).
Attachments
Driver data is here http://www.diyaudio.com/forums/showthread.php?postid=951263#post951263 and Scott's kind response is here http://www.diyaudio.com/forums/showthread.php?postid=951911#post951911
Thanks Dave and others for taking the interest.
If all goes well, this should provide some more insight into a proper implementation of an iBIBk.
Thanks Dave and others for taking the interest.
If all goes well, this should provide some more insight into a proper implementation of an iBIBk.
Hmm, a K-slot is for smoothing out the response, so you normally would either close off the bottom and let it be the vent or gap it to the floor such that it causes an under-damped 'boomy' (high Q) response, then add a slot as required to smooth (critically damp) it out, which also tune it higher. Since this is a floor loaded horn, then assuming the driver is at the desired height the vents you so carefully cut out need to be blocked off as required to get the initial under-damped response.
GM, thanks for having a look.
However, having carefully followed this thread, I was given to understand that the slots need to add up to Sm and additionally the K-slot is also cut, either on one of the sides or dividing the K-slot itself into two vertical halves and placing them on either sides. (Correct me if I understood wrong).
Cutting off the extra part, now acting as feet will bring the line length to what it should be, putting it directly on the floor and make provision for cutting a critically damped K-slot.
However, what makes me really wonder is that when I rotate my cab around by 180 degrees and put the opening to the ceiling, I get just about sufficient bass, only with corner placement. The only extras that don't make it a true BIB in this turned down-side-up position are the three feet (measuring 4" height x 1.5" width) and one side (measuring 4" x 9.5" width).
Nonetheless, the BIB are known to produce prodigious bass while my implementation does not.
Could the dims be wrong or did I make a mistake with the build?
However, having carefully followed this thread, I was given to understand that the slots need to add up to Sm and additionally the K-slot is also cut, either on one of the sides or dividing the K-slot itself into two vertical halves and placing them on either sides. (Correct me if I understood wrong).
Cutting off the extra part, now acting as feet will bring the line length to what it should be, putting it directly on the floor and make provision for cutting a critically damped K-slot.
However, what makes me really wonder is that when I rotate my cab around by 180 degrees and put the opening to the ceiling, I get just about sufficient bass, only with corner placement. The only extras that don't make it a true BIB in this turned down-side-up position are the three feet (measuring 4" height x 1.5" width) and one side (measuring 4" x 9.5" width).
Nonetheless, the BIB are known to produce prodigious bass while my implementation does not.
Could the dims be wrong or did I make a mistake with the build?
Dimensions are fine -I've just rechecked it. So, two possible conclusions. A) you've made a mistake in the build thus far, which seems unlikely from your description, or B) the T/S parameters you originally gave are wrong. Were these measured, or are they the manufacturers claims? If it's the latter, methinks that's where the trouble most likely lies as some are a little, shall we say, 'creative' with their stated figures.
Couple of other points -what's the QW cabinet design that you mentioned? The other is that the 127 iBIB is spaced so that about 1/2 the CSA of Sl is provided by elevating the enclosure, and the rest by the K-slot -it's not Sl + the slot.
Couple of other points -what's the QW cabinet design that you mentioned? The other is that the 127 iBIB is spaced so that about 1/2 the CSA of Sl is provided by elevating the enclosure, and the rest by the K-slot -it's not Sl + the slot.