Oh Boy, more people asking about this project...
I prefer to put my horns in a small but separate compartment to keep the bass vibrations from affecting the tweeter by making the horn resonate, In this case the bass is probably going to affect it some anyway but still, a tiny compartment extending into the horn shouldn't be a problem.
A good way to make this compartment is to glue a capped cardboard or PVC tube to the back of the wall, enclosing the tweeter. For the FT17 a 3" tube would be fine, and the tweeter doesn't protrude more than 3/4" into the interior , so the tube would only protrude 2 inches at most.
On the other hand, if you just mount the FT 17 tweeter in the cavity, it will protrude 3/4" at most, and is 2 1/2" dia. With a double baffle thickness as I show in the plans, an unenclosed tweeter wil not intrude at all into the cavity.
Send us the pics of your project!
I prefer to put my horns in a small but separate compartment to keep the bass vibrations from affecting the tweeter by making the horn resonate, In this case the bass is probably going to affect it some anyway but still, a tiny compartment extending into the horn shouldn't be a problem.
A good way to make this compartment is to glue a capped cardboard or PVC tube to the back of the wall, enclosing the tweeter. For the FT17 a 3" tube would be fine, and the tweeter doesn't protrude more than 3/4" into the interior , so the tube would only protrude 2 inches at most.
On the other hand, if you just mount the FT 17 tweeter in the cavity, it will protrude 3/4" at most, and is 2 1/2" dia. With a double baffle thickness as I show in the plans, an unenclosed tweeter wil not intrude at all into the cavity.
Send us the pics of your project!
Greets!
It's not good for speaker building unless 'An' grade IMO, then needs to be >1" thick to match 19 mm Baltic Birch, Appleply, or marine grade's stiffness and probably at least 19 mm to match the furniture grade Birch or Oak veneer, so ideally significantly more bracing will be required on a large cab.
Since this is an 'el cheapo' project though, use it and only add braces based on how resonant a cab you'll tolerate.
GM
It's not good for speaker building unless 'An' grade IMO, then needs to be >1" thick to match 19 mm Baltic Birch, Appleply, or marine grade's stiffness and probably at least 19 mm to match the furniture grade Birch or Oak veneer, so ideally significantly more bracing will be required on a large cab.
Since this is an 'el cheapo' project though, use it and only add braces based on how resonant a cab you'll tolerate.
GM
if you get 1" thick then you or I will need to adjust the dimensions a small amount. No problem though...
Don't know about that ply. That cheaper "Imported Birch" is 11 ply but was a lot more than $23. Them most important thing from what I've heard is whether it has voids, ie hollow spots between some layers. You can look at the edge to see about this somewhat.. voids are bad....
Again , I'm not an expert, but it it had no voids or only very small ones,
and you braced across the wide parts with 2x2 or closet hanger rod, it probably will work.
Don't know about that ply. That cheaper "Imported Birch" is 11 ply but was a lot more than $23. Them most important thing from what I've heard is whether it has voids, ie hollow spots between some layers. You can look at the edge to see about this somewhat.. voids are bad....
Again , I'm not an expert, but it it had no voids or only very small ones,
and you braced across the wide parts with 2x2 or closet hanger rod, it probably will work.
The biggest problem you'll run into from voids is buzzing and rattling. If this happens, you can track down the source of the buzz with a stethoscope and drive a wood screw through it and tighten it down really tight. This wouldn't be tolerable for most people's aesthetics, but something tells me that you'll find a way to tolerate a few screws stuck into the cabinets.
Any idea how you're going to finish them? I was in a fabric store once, and they were selling rolls fake fur by the yard- like the kind of fur you would use if you were making a gorilla suit. For a project like these, that would be really out there.
Edit- I just installed Math Cad on my new laptop, so I'm going to have a look at the simulation.
Any idea how you're going to finish them? I was in a fabric store once, and they were selling rolls fake fur by the yard- like the kind of fur you would use if you were making a gorilla suit. For a project like these, that would be really out there.
Edit- I just installed Math Cad on my new laptop, so I'm going to have a look at the simulation.
Video for scale
I was fooling around with an animation program (looking for ways to exercise the new laptop
), and I whipped up this little fly-around to give a good idea of the scale of the speaker.
http://jzoe.com/movies/bibb.avi
It didn't seem to like playing in Winamp, but played OK in windows media player.
I still didn't get around to running a mathcad simulation- Variac, can you please indicate the post number with the "official" dimensions? Thanks in advance.
I was fooling around with an animation program (looking for ways to exercise the new laptop
), and I whipped up this little fly-around to give a good idea of the scale of the speaker.http://jzoe.com/movies/bibb.avi
It didn't seem to like playing in Winamp, but played OK in windows media player.
I still didn't get around to running a mathcad simulation- Variac, can you please indicate the post number with the "official" dimensions? Thanks in advance.
27"x19" internal size
#64:
http://www.diyaudio.com/forums/showthread.php?postid=1031054#post1031054
I hope to post some slightly more detailed plans soon, but punkrockr has enough info to make them.
Love the fly around!!! Really gives a sense of the size.
- need to show the thicker middle part of the front baffle and tweeter
#64:
http://www.diyaudio.com/forums/showthread.php?postid=1031054#post1031054
I hope to post some slightly more detailed plans soon, but punkrockr has enough info to make them.
Love the fly around!!! Really gives a sense of the size.
- need to show the thicker middle part of the front baffle and tweeter
Cool video fly around, thanks!
I mentioned the BBBIB project to a speaker buliding buddy of mine who has built a LOT of speakers over the years, and has helped me on a few.
He says that he once built a Voit Pipe with the old version of Beta LTA.
He's going to see if he can find photos of it.
So sounds promising.
Has Mr. P gone off to buy wood this weekend?
I mentioned the BBBIB project to a speaker buliding buddy of mine who has built a LOT of speakers over the years, and has helped me on a few.
He says that he once built a Voit Pipe with the old version of Beta LTA.
He's going to see if he can find photos of it.
So sounds promising.
Has Mr. P gone off to buy wood this weekend?
Hey guys, glad you enjoyed the video. I think it's a codec problem, but I'm not really in the mood to wade through all that right now.
I tried running some simulations on the Mathcad worksheets, and with the present design I ended up running into a major dips between 100 and 200 hz. Adding stuffing helps, but you'll need a huge quantity of it to do any good.
I tried running some simulations on the Mathcad worksheets, and with the present design I ended up running into a major dips between 100 and 200 hz. Adding stuffing helps, but you'll need a huge quantity of it to do any good.
Mine were a little higher in frequency, and a little deeper. Adding stuffing of around 0.5 lb/cu ft got the depth fairly close.
To be honest, this box is getting large enough that the in-room response is liable to start diverging from the prediction. I remember that the worksheets were designed to give anechoic response, but I don't remember how the physical arrangement of the woofer and terminus are accounted for. I know that my simulation did not include the bend...
If we're ready to go on this, I guess I'm not sure enough about my interpretation to call it off. As long as he can get some polyfill stuffing in bulk, and has some form of EQ, all should be well.
To be honest, this box is getting large enough that the in-room response is liable to start diverging from the prediction. I remember that the worksheets were designed to give anechoic response, but I don't remember how the physical arrangement of the woofer and terminus are accounted for. I know that my simulation did not include the bend...
If we're ready to go on this, I guess I'm not sure enough about my interpretation to call it off. As long as he can get some polyfill stuffing in bulk, and has some form of EQ, all should be well.
Hi!
I'm by all means no expert on loudspeakers but have built a BIB.
This dip above 100-200 hz will be more or less flatened in room.
DO NOT STUFF TOO MUCH. You will kill the dynamics.
Stuff the closed end of pipe with polyester filling for pillows.
Dens at the beginning and looser down to driver.
Put one inch BAF wadding behind driver and down 8 inch from speaker and finally one inch on the bottom will probably be enough.
I really must say that these will be scary in terms of bass output!!! My 5 inchers in a BIB, fill my 50 sqm room with both quality and volume.
Hope punkrocker has connections within the decibel police
Good luck/Peter
I'm by all means no expert on loudspeakers but have built a BIB.
This dip above 100-200 hz will be more or less flatened in room.
DO NOT STUFF TOO MUCH. You will kill the dynamics.
Stuff the closed end of pipe with polyester filling for pillows.
Dens at the beginning and looser down to driver.
Put one inch BAF wadding behind driver and down 8 inch from speaker and finally one inch on the bottom will probably be enough.
I really must say that these will be scary in terms of bass output!!! My 5 inchers in a BIB, fill my 50 sqm room with both quality and volume.
Hope punkrocker has connections within the decibel police
Good luck/Peter
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