Great to know how to calculate the mass corner. Now I just need to know why I need to know that.
The short answer is that all sealed, vented speaker design programs uses math that causes the box's impact on the driver's LF on up performance to peter out/fade away by this point.
GM
GM
It's in some texts (Keele, Leach etc.) but frequently overlooked on-line. With the exception of GMs posts & probably some by Tom Danley etc. 😉
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It was about eight years ago Scott that you and Daniel convinced me to build a Fostex 208/T90A BIB. It is pretty much all I have been listening to since. A few short months ago I finally got a SET amp. A 45 Tube (1.5W) SET amp designed by Paul Weitzel of Tube Research Labs. The sound is REALLY nice. But today I found out that Paul, who has suffered from pancreatitis for years, passed away Yesterday afternoon! A man with a gift (the circuit meister) has departed from our midst.
I have been thinking about trying an open baffle lately. I can not use the Fostex 208 because I cemented it into my BIB. One single driver is somewhat attractive to me. I have been looking around on the forums. If you guys want to point me towards a certain driver or design I would give it GREAT weight. Above all, it would have to work well with my 1.5W SET amp!
I have been thinking about trying an open baffle lately. I can not use the Fostex 208 because I cemented it into my BIB. One single driver is somewhat attractive to me. I have been looking around on the forums. If you guys want to point me towards a certain driver or design I would give it GREAT weight. Above all, it would have to work well with my 1.5W SET amp!
Sorry to hear about Paul. I never had any dealings with TRL, but it's always sad to learn that someone has passed on.
Re the baffles, there aren't all that many choices if you just want a single unit. Basically it's a case of something with a low mass corner so there is a chance of it producing some semblance of bass. The high output impedance of a low power SET will help there of course.
At the smaller end there's something like the Visaton B200. If you want larger, the Audio Nirvana 15in AlNiCo model should do the job. Otherwise, it's a case of truffling through eBay or similar for vintage drivers or new-build types with a high Q.
Re the baffles, there aren't all that many choices if you just want a single unit. Basically it's a case of something with a low mass corner so there is a chance of it producing some semblance of bass. The high output impedance of a low power SET will help there of course.
At the smaller end there's something like the Visaton B200. If you want larger, the Audio Nirvana 15in AlNiCo model should do the job. Otherwise, it's a case of truffling through eBay or similar for vintage drivers or new-build types with a high Q.
We have Music!
So I have been working on my 8ft tall Bibs in my 9ft tall room (see picture on post# 5384) and I was having trouble getting them to sound Musical. They played big. They played bass, but the Music had eluded me.
Short reply. Now I have Music. and bass and it is BIG! 🙂 When my wife and kids are dancing and singing to "Rock and Roll" by Zeppelin. You know something is working right.
Long reply.
I will type this out because my experience may help someone else. I have made some questionable decisions along the way, but I have more small children than time so that is the excuse I will use right now. I built a Bib speaker back in july using the bib calculator and the helpful advice of GM. Thanks again Greg. Since I have a SET amp I sized up the Qts according to the high impedance amp. I own a pair of FE166E (Fs-50hz, Qts-0.21) and a pair of FE166En (Fs-53hz, Qts-0.25). I initially built using the FE166E. and my other speaker was a BLH, a BK-16 from Madisound, also with a FE166E. And I started tuning the BIB. I made it taller. I tried in the corner. I tried an internal baffle (see sketch on post#5387), I tried different gauge wire, I tried different series resistors. But I could never get it to sound cohesive or musical. I was able to build the 2nd Bib in December to match the 1st. As a pair, I still had the same problem. More tuning, but no luck. Not musical, not cohesive. My amp is a Bottle S.E.X. amp. and I have an older version with small output transformers. In December I installed the "iron upgrade" which included larger output transformers and I probably gained an octave on the low end. With the new output transformers installed I had even more bass with my bibs, but still not cohesive or musical. and I took them out and replaced them with my BLH's for several weeks. The BLH's are very musical speakers as tuned.
So just before I put saw to wood and converted my Bibs to Inverted Bibs, I went back to the beginning. I installed the FE166En drivers which have a slightly higher Qts, I removed any series resistance. I took the internal baffles out, and I took out the stuffing in the point. I weighed the stuffing and then put double the amount back in. Then hooked them up. and my jaw dropped. MUSIC! and these 8ft monoliths disappear. 🙂.
So now my stuffing in the point ,all above the driver, is 0.75lbs/ft3. It might not sim well, but I know I like the way it sounds. They play down to ~30hz based on pink noise and a frequency analyzer phone app, so take that with a grain of salt. They are still 8ft tall and 1 ft from the ceiling. I have them against the wall, not in the corners.
So I am going to live with them for several weeks before I try anything else. Play with placement some and maybe stuffing (slightly less) later. So far they have had some Magic Sam, Muddy Waters, Bob Marley, Jimi, Zeppelin, and Willie. They will get a healthy dose of blues this week as well as some more rock n' roll.
Thanks again to this board and this thread and GM.
last note. I did play pink noise through them with the larger output transformers and the internal baffle still installed and they measured flat to 20hz out the top of the BIB. So I may play around with the internal baffle in some form.
So I have been working on my 8ft tall Bibs in my 9ft tall room (see picture on post# 5384) and I was having trouble getting them to sound Musical. They played big. They played bass, but the Music had eluded me.
Short reply. Now I have Music. and bass and it is BIG! 🙂 When my wife and kids are dancing and singing to "Rock and Roll" by Zeppelin. You know something is working right.
Long reply.
I will type this out because my experience may help someone else. I have made some questionable decisions along the way, but I have more small children than time so that is the excuse I will use right now. I built a Bib speaker back in july using the bib calculator and the helpful advice of GM. Thanks again Greg. Since I have a SET amp I sized up the Qts according to the high impedance amp. I own a pair of FE166E (Fs-50hz, Qts-0.21) and a pair of FE166En (Fs-53hz, Qts-0.25). I initially built using the FE166E. and my other speaker was a BLH, a BK-16 from Madisound, also with a FE166E. And I started tuning the BIB. I made it taller. I tried in the corner. I tried an internal baffle (see sketch on post#5387), I tried different gauge wire, I tried different series resistors. But I could never get it to sound cohesive or musical. I was able to build the 2nd Bib in December to match the 1st. As a pair, I still had the same problem. More tuning, but no luck. Not musical, not cohesive. My amp is a Bottle S.E.X. amp. and I have an older version with small output transformers. In December I installed the "iron upgrade" which included larger output transformers and I probably gained an octave on the low end. With the new output transformers installed I had even more bass with my bibs, but still not cohesive or musical. and I took them out and replaced them with my BLH's for several weeks. The BLH's are very musical speakers as tuned.
So just before I put saw to wood and converted my Bibs to Inverted Bibs, I went back to the beginning. I installed the FE166En drivers which have a slightly higher Qts, I removed any series resistance. I took the internal baffles out, and I took out the stuffing in the point. I weighed the stuffing and then put double the amount back in. Then hooked them up. and my jaw dropped. MUSIC! and these 8ft monoliths disappear. 🙂.
So now my stuffing in the point ,all above the driver, is 0.75lbs/ft3. It might not sim well, but I know I like the way it sounds. They play down to ~30hz based on pink noise and a frequency analyzer phone app, so take that with a grain of salt. They are still 8ft tall and 1 ft from the ceiling. I have them against the wall, not in the corners.
So I am going to live with them for several weeks before I try anything else. Play with placement some and maybe stuffing (slightly less) later. So far they have had some Magic Sam, Muddy Waters, Bob Marley, Jimi, Zeppelin, and Willie. They will get a healthy dose of blues this week as well as some more rock n' roll.
Thanks again to this board and this thread and GM.
last note. I did play pink noise through them with the larger output transformers and the internal baffle still installed and they measured flat to 20hz out the top of the BIB. So I may play around with the internal baffle in some form.
update
So I have done minimal tuning since the last update. I removed some of the stuffing above the speaker. I thought I was loosing some dynamics because the box might be overstuffed. I took out one large handful. But after reassembly, the music was gone. They were no longer musical. 🙁 Nobody sang along or felt like dancing. So I put the stuffing back in and the singing started again and there was some dancing. So I am leaving well enough alone and just enjoying music.
Now I need to finish them out.
Thanks again for a rewarding speaker build.
So I have done minimal tuning since the last update. I removed some of the stuffing above the speaker. I thought I was loosing some dynamics because the box might be overstuffed. I took out one large handful. But after reassembly, the music was gone. They were no longer musical. 🙁 Nobody sang along or felt like dancing. So I put the stuffing back in and the singing started again and there was some dancing. So I am leaving well enough alone and just enjoying music.
Now I need to finish them out.
Thanks again for a rewarding speaker build.
You're welcome!
LOL! 🙂 Yeah, pipe horns can be pretty finicky to tune, but in general the closed end needs a very 'plush pillow' [I've been known to use cheap, old 'throw' pillows] to damp excess harmonic output with a nominal amount behind the driver same as any cab, then some down on its 'floor' to control reflections back up to the driver and do all fine tuning at the terminus to 'critically' damp it same as damping a reflex vent. Of course one of any parallel walls need to be lined same as any cab.
GM
LOL! 🙂 Yeah, pipe horns can be pretty finicky to tune, but in general the closed end needs a very 'plush pillow' [I've been known to use cheap, old 'throw' pillows] to damp excess harmonic output with a nominal amount behind the driver same as any cab, then some down on its 'floor' to control reflections back up to the driver and do all fine tuning at the terminus to 'critically' damp it same as damping a reflex vent. Of course one of any parallel walls need to be lined same as any cab.
GM
need help with dimensions of GRS 4FR-8 4.5" speaker
This drivers supposed to be drop in replacement for the classic Pioneer A11 speaker but using the BIB calculator v2, I am getting very different numbers.
Can someone help me out? What should be the size??
--
Resonant Frequency (Fs)100 Hz
Total Q (Qts)0.82
Compliance Equivalent Volume (Vas)0.11 ft.³
--
thanks
This drivers supposed to be drop in replacement for the classic Pioneer A11 speaker but using the BIB calculator v2, I am getting very different numbers.
Can someone help me out? What should be the size??
--
Resonant Frequency (Fs)100 Hz
Total Q (Qts)0.82
Compliance Equivalent Volume (Vas)0.11 ft.³
--
thanks
Attachments
Greets!
Don't have the various programs loaded to do any calcs, sims, though remember that the A11's actual specs are way different than published to the point where the GRS should theoretically work OK in the existing BIB with maybe just some more damping added to 'taste' IF its specs aren't too far off also.
Only one way to know for sure though...........
GM
Don't have the various programs loaded to do any calcs, sims, though remember that the A11's actual specs are way different than published to the point where the GRS should theoretically work OK in the existing BIB with maybe just some more damping added to 'taste' IF its specs aren't too far off also.
Only one way to know for sure though...........
GM
GRS 4FR-8
Hi, not sure about the Pioneer but with the specs you provided I get the following internal dims using one of GM's calculators:
Height: 33,66"
Depth: 11,16
Widget: 7,89
driver: 14,61
I would personally flip it over and change the zdriver to approx .4 line length. I would also tune lower to make a taller, skinnier box. Shouldn't be a problem with wall/corner loading. Hopefully someone more knowledgeable will chip in. 🙂
Hi, not sure about the Pioneer but with the specs you provided I get the following internal dims using one of GM's calculators:
Height: 33,66"
Depth: 11,16
Widget: 7,89
driver: 14,61
I would personally flip it over and change the zdriver to approx .4 line length. I would also tune lower to make a taller, skinnier box. Shouldn't be a problem with wall/corner loading. Hopefully someone more knowledgeable will chip in. 🙂
BIB Calculators here.
https://speakerprojects.wordpress.com/cabinet-types/bib-loudspeakers/bib-calculator/
https://speakerprojects.wordpress.com/cabinet-types/bib-loudspeakers/bib-calculator/
Yes, with such a high Fs it's too short for a BIB or even a floor-stander and for a floor/vented loaded pipe horn the driver IME typically works best overall in the 0.5-0.56 range; though not 'skinnier', but larger by continuing the expansion [i.e. design to a lower 'Fs' to get the desired driver/floor height] same as required for any horn tuned lower otherwise it will not 'prop up' [protect] the driver's bass response enough and require too much stuffing due to excessive 'ripple'.
Way back when cabs were often still pretty big by today's standards, folks thought me nuts when they'd see a cheap 6.5-8" 'FR' driver or woofer in up to a ~8 ft^3 tower [vented pipe horn/ML-Voigt/ML-horn] until I cranked up Rick Wakeman's Cathedral pipe organ enhanced scores, DSOTM, Altec's VoTT demo or similar LPs of the day with output to <40 Hz and/or lower than average compression mid-bass.
GM
I just assumed the Vas and Qts remain the same, in which case a longer line means a smaller width x depth. So keep the footprint the same and just make the cab taller, 48" for example?
So for a down firing BIB recommended zdriver is .5 to .56 line length? That would put the driver on the top of the cab or facing the wall? 😕 I guess the cab could be lifted off the floor but I just built mine firing out the back to be able to space close to the wall.
Ok, after reading about Mr. Brines FAST setup and doing a couple of searches and seeing multiple post of Greg (GM) reference a FAST setup with tqwt speakers I thought why not.
So Greg I am open to being a Guinea pig.
What prompted this is two things. One, a pool table to put in my 2 car garage and two my family has acclimated to 8 foot tall speakers in the house. So maybe I make a set of FAST bib's and play with them in the garage. And if I like the results then I could move them inside.
So I figure 8 foot tall because that is fewer cuts and less work. The garage ha 9'4" ceilings. And pick a woofer to match the 8' folded length. And a sealed box for the full range. I have to think about that part. And crossed over as a FAST.
So Greg, what say you?
So Greg I am open to being a Guinea pig.
What prompted this is two things. One, a pool table to put in my 2 car garage and two my family has acclimated to 8 foot tall speakers in the house. So maybe I make a set of FAST bib's and play with them in the garage. And if I like the results then I could move them inside.
So I figure 8 foot tall because that is fewer cuts and less work. The garage ha 9'4" ceilings. And pick a woofer to match the 8' folded length. And a sealed box for the full range. I have to think about that part. And crossed over as a FAST.
So Greg, what say you?
Correct.
Well, my assumption here is that with down-firing there will be more mass [vent] loading, which shifts the pipe harmonics lower. Folks use to say I was wrong till MJK published his ML-TQWT doc, which has the driver at 0.5.
I guess due to using much longer, 'slower' expansions for my BIB variants than his, even a bit lower worked well.
Regardless, getting the driver up to ear height and/or a vertical room mode takes precedence over getting the absolute 'smoothest' pipe response since stuffing will cure all but the most egregious mis-alignments.
GM