8cx or 8bx ?
8cx has Fs of75 Hz and 8bx has Fs of 52 Hz. Both have xmax of 5mm both have lots of xlim.
8cx has Fs of75 Hz and 8bx has Fs of 52 Hz. Both have xmax of 5mm both have lots of xlim.
Another BIB on Earth ?
Hi, Ladies(?) and Gentlemen,
This is my first post, so many thanks for the incredible job.
I followed the thread from the beginning (with the help of translating machine), and it was exciting.
So, 1 year later, big decision in the real life : I got a pair of FE168EZ !
This is my first DIY project and I hope it’s a good choice… but for the moment I’m breaking them in a 55 litres vented box and they sound a little bit harsh and boomy 🙁 so I plan to move them quickly to the final box.
Now, I have a question for Scottmoose :
On zillaspeak.com the recommended line length for the FE168EZ BIB is 128" vs. 136" for the FE166/167E.
( http://www.zillaspeak.com/bib-fostex.asp )
Why such a difference, as Fs is about the same (50/51 Hz) for 168 and 166/167 models ?
I ask that cause I have some 69” plywood pieces so I can set the BIB for 51hz.
Do you think it’s too low and could have some bad effects ?
I specify my room is 15 sq/meters, I never play loud due to the neighbourhood and the BIB’s will not be in a corner but 5” from the wall.
Many thanks.
Hi, Ladies(?) and Gentlemen,
This is my first post, so many thanks for the incredible job.
I followed the thread from the beginning (with the help of translating machine), and it was exciting.
So, 1 year later, big decision in the real life : I got a pair of FE168EZ !
This is my first DIY project and I hope it’s a good choice… but for the moment I’m breaking them in a 55 litres vented box and they sound a little bit harsh and boomy 🙁 so I plan to move them quickly to the final box.
Now, I have a question for Scottmoose :
On zillaspeak.com the recommended line length for the FE168EZ BIB is 128" vs. 136" for the FE166/167E.
( http://www.zillaspeak.com/bib-fostex.asp )
Why such a difference, as Fs is about the same (50/51 Hz) for 168 and 166/167 models ?
I ask that cause I have some 69” plywood pieces so I can set the BIB for 51hz.
Do you think it’s too low and could have some bad effects ?
I specify my room is 15 sq/meters, I never play loud due to the neighbourhood and the BIB’s will not be in a corner but 5” from the wall.
Many thanks.
Good question. This was one of my earlier cabs, and since then I've revised some of my views. A longer line is quite possible for the Esigma, so yes, by all means, use the material you have.
[
gychang -dimensions are off. 7in wide x 9in deep will give you a 63in^2 terminus, but depth ideally wants to be as near as practicable to 1.4142W, so I would use 6.75in wide x 9.5in deep (internal) This is a fraction more than the 63in terminus, but it will give the ~ correct conical expansion rate, and better too large than too small. The cabinet ideally will need to be 49.5in tall to account for the bend at the base of the cabinet while preserving the designed line length. Terminate the internal baflle 4.75in from the front & real walls & the floor.
]
I am getting ready to cut wood at last for my sample bib.
Gychang and others: Any final remarks to add to the dimensions given
above?
Are you chamfering the driver hole with your new router?
I'm glad I went back and re-read some of this stuff. I might have had kindling otherwise.
gychang -dimensions are off. 7in wide x 9in deep will give you a 63in^2 terminus, but depth ideally wants to be as near as practicable to 1.4142W, so I would use 6.75in wide x 9.5in deep (internal) This is a fraction more than the 63in terminus, but it will give the ~ correct conical expansion rate, and better too large than too small. The cabinet ideally will need to be 49.5in tall to account for the bend at the base of the cabinet while preserving the designed line length. Terminate the internal baflle 4.75in from the front & real walls & the floor.
]
I am getting ready to cut wood at last for my sample bib.
Gychang and others: Any final remarks to add to the dimensions given
above?
Are you chamfering the driver hole with your new router?
I'm glad I went back and re-read some of this stuff. I might have had kindling otherwise.
Gents,
I've considered using a pair of my Kenwood 6"x9" fullrangers in BiB, but from what I've gathered wading through this enormous thread, they wouldn't be ideal, or at least would require a huge cabinet.
So, I'm wondering exactly how large.
They seem to be pretty similar to Pioneer B20s, but I'm guessing the Qts. is around .7 or a little above, and an Fs a touch under the B20s. The B20s have a reasonable line length, but one of the largest mouth areas on Zilla's site. I can probably get larger mouth area without much trouble, but any significantly longer line length would have to get at least one extra fold (probably 2 because I would like to floor load). I've got 6 of these things, so if I can come up with a reasonable design, I could use them all over the house.
Kensai
I've considered using a pair of my Kenwood 6"x9" fullrangers in BiB, but from what I've gathered wading through this enormous thread, they wouldn't be ideal, or at least would require a huge cabinet.
So, I'm wondering exactly how large.
They seem to be pretty similar to Pioneer B20s, but I'm guessing the Qts. is around .7 or a little above, and an Fs a touch under the B20s. The B20s have a reasonable line length, but one of the largest mouth areas on Zilla's site. I can probably get larger mouth area without much trouble, but any significantly longer line length would have to get at least one extra fold (probably 2 because I would like to floor load). I've got 6 of these things, so if I can come up with a reasonable design, I could use them all over the house.
Kensai
We're shooting in the dark. Without knowing Qt, Fs, Re and Vas it's just guesswork. You could try them in the B20 line I suppose, but unless you can get them measured there's no way of being certain I'm afraid.
Yeah, I know there's no way of being certain, but even after slogging through this whole thread trying to catch up, I haven't figured out how changing any of the driver specs changes the line length, mouth area or Zdriver point. Would a higher Qts need a larger mouth area and a lower Fs need a longer line? I was intending to just knock something together using standard sized lumber to minimize cutting, anyway so anything I would do with this information would only be approximate, and I certainly wouldn't be holding anyone liable for solicited suggestions . . .
Kensai
Kensai
Length is determined by 1/2 wavelength of the design cut off frequency. There are a few ways of deciding what this frequency is -I usually go with Fs, or 1 octave above or below Fs (or thereabouts). Cabinet volume is determined by a host of factors -Vas, Q, and even Re. Terminus conforms to the usual horn proceedure for 1/8 space loading and circumference.
As we've no real way of determining anything short of getting the parameters measured, and sticking to your guesses, whoich I suspect are pretty much on the money, I'd try them in the Pioneer B20 cabinet. If the worst came to the worst, you could always drop a set of B20s into them as they're unlikely to break the bank. 😉
As we've no real way of determining anything short of getting the parameters measured, and sticking to your guesses, whoich I suspect are pretty much on the money, I'd try them in the Pioneer B20 cabinet. If the worst came to the worst, you could always drop a set of B20s into them as they're unlikely to break the bank. 😉
I started to think about attaching secondary baffles of
the circular or oval type.
Only real idea I had to do this would be to use t-nuts
on the back side of the secondary baffle and another set
in a star pattern on the front and draw down the screw
between the 2. A piece of rubber gasketing could be used
for a seal.
Anyone else have any insight on this?
the circular or oval type.
Only real idea I had to do this would be to use t-nuts
on the back side of the secondary baffle and another set
in a star pattern on the front and draw down the screw
between the 2. A piece of rubber gasketing could be used
for a seal.
Anyone else have any insight on this?
Loninappleton
I was trying several deflector configurations with my BIB's...FE168EZ's... but set the project aside to finish my Fonkens....which I finished yesterday.
Your approach of bolting the deflector to the baffle then bolting the driver to the deflector is pretty much what I settled on. I started with two stacked discs of 3/4" MDF; one was 9 1/2" in diameter and the other was 11". Both had their edges beveled at 45* with driver holes routed and were glued together. I also routed a trough on the back of deflector equal to the width of the front of the enclosure to reduce the thickness / height of the deflector. It became a saddle across the driver opening. Another disc 12 1/2" was cut, beveled and, from the back, rounded over. Only a portion of this disc was used since it was to be applied to each side (east-west) of the enclosure to extend the width of the deflector and round the edges rearward as indicated by Olson et.al.
As I said earlier I did not finish the project but intend to get back to it since I finished the Fonkens. Let me know if this helps and what you come up with.
Ray
I was trying several deflector configurations with my BIB's...FE168EZ's... but set the project aside to finish my Fonkens....which I finished yesterday.
Your approach of bolting the deflector to the baffle then bolting the driver to the deflector is pretty much what I settled on. I started with two stacked discs of 3/4" MDF; one was 9 1/2" in diameter and the other was 11". Both had their edges beveled at 45* with driver holes routed and were glued together. I also routed a trough on the back of deflector equal to the width of the front of the enclosure to reduce the thickness / height of the deflector. It became a saddle across the driver opening. Another disc 12 1/2" was cut, beveled and, from the back, rounded over. Only a portion of this disc was used since it was to be applied to each side (east-west) of the enclosure to extend the width of the deflector and round the edges rearward as indicated by Olson et.al.
As I said earlier I did not finish the project but intend to get back to it since I finished the Fonkens. Let me know if this helps and what you come up with.
Ray
Kensai said:
Greets!
Indeed! In the (not so) good ol' days, the DIYer often scaled a box, vent size from a nomograph where Av= Sd at some stupendous Vb based on published Fs, but pipes are a bit different and we don't know its Fs, so it's a complete crapshoot. That said, a fairly long pipe will load the room pretty good regardless of the driver's specs if it's big enough, so all we need to do is tune it somewhat below Fs and oversize its Vb enough to ensure some tuning flexibility.
Using the reference 138" line length, this puts Fc into the 30s, so probably low enough and a ~8*Sd = 340"^2 terminus ought to be big enough, or ~21.93" D x 15.5" W base inside dims. Not exactly svelte, but if you're not willing/able to measure its specs......... Regardless, most folks that have A/B'd these rule-of-thumb cabs Vs the usually much smaller, but same T/S variant designs prefer the more 'relaxed' sounding big cabs/pipes.
As always though, YMMV.
GM
I still don't understand how you guys are calculating the terminus surface area.
The designs seem to go from about 4.25X to 8X driver Sd. What other factors determine the terminus (mouth) surface area? Tuning frequency? Driver Q?
The designs seem to go from about 4.25X to 8X driver Sd. What other factors determine the terminus (mouth) surface area? Tuning frequency? Driver Q?
Tuning frequency (so the mouth is balanced to line length), driver Q, Re, necessary Vb. It's a blend of these factors really.
So, for playing around with drivers like this, I would be best served building "mule" cabs with a removeable baffle area for mounting different drivers at different heights on the front and with a generous mouth area, eh? Floor loading them like I plan I could easily keep the cutoffs together to use in triming the mouth area for experimentation.
Man, so much woodworking, so little tools, er, time.
I'm probably going to still start with the little B3S BiBs when my schedule slacks up. Those at least will be small enough to be "utility" speakers that won't need to be adjusted to fit a certain space.
Good stuff guys. Thanks.
Kensai
Man, so much woodworking, so little tools, er, time.
I'm probably going to still start with the little B3S BiBs when my schedule slacks up. Those at least will be small enough to be "utility" speakers that won't need to be adjusted to fit a certain space.
Good stuff guys. Thanks.
Kensai
baffle high question
Hey guys,
I have a question about the baffle hight from the bottom. I already made a pair of BIBs for the FE127s but I did not know about the ratio and made them out of MDF. So now I want to make a new pair out of birch ply and with the correct ratio but still I'm puzzled about the baffle hight. Now my speaker is to be 9.5 inches deep. So if you take half of that it will be 4.75 from the front, back, and bottom. But the baffle thickness is .75 so the baffle is going to be .375 smaller front and back but the bottom could be 4.75 inches. So should I make the distance from the bottom .375 smaller or not worry about it. My problem is that I like having things perfect. This answer might be hidden in the pages somewhere but I don't remember seeing it. I am attaching a picture to be more clear. Thanks for the help.
John
Hey guys,
I have a question about the baffle hight from the bottom. I already made a pair of BIBs for the FE127s but I did not know about the ratio and made them out of MDF. So now I want to make a new pair out of birch ply and with the correct ratio but still I'm puzzled about the baffle hight. Now my speaker is to be 9.5 inches deep. So if you take half of that it will be 4.75 from the front, back, and bottom. But the baffle thickness is .75 so the baffle is going to be .375 smaller front and back but the bottom could be 4.75 inches. So should I make the distance from the bottom .375 smaller or not worry about it. My problem is that I like having things perfect. This answer might be hidden in the pages somewhere but I don't remember seeing it. I am attaching a picture to be more clear. Thanks for the help.
John
Attachments
Re: baffle high question
Greets!
Rightly or wrongly, I followed TC's sketch, which shows the internal baffle stopping short of the top, making the terminus and base area ~the same. If you run it all the way up, then the line will be fractionally longer and the terminus area fractionally smaller, but not enough to matter unless it's already way undersized to start with. Using TC's cab ratio Vs my theoretically correct one will theoretically have more impact on the FR, and even then it's probably not audible in-room. Still, it's best to stop it short to create a ledge for a grill or filter if required.
GM
Greets!
Rightly or wrongly, I followed TC's sketch, which shows the internal baffle stopping short of the top, making the terminus and base area ~the same. If you run it all the way up, then the line will be fractionally longer and the terminus area fractionally smaller, but not enough to matter unless it's already way undersized to start with. Using TC's cab ratio Vs my theoretically correct one will theoretically have more impact on the FR, and even then it's probably not audible in-room. Still, it's best to stop it short to create a ledge for a grill or filter if required.
GM
