You're welcome!
Don't know, IIRC the smallest drivers I used in pipe horns were 12" and were never 'asked' to play below 40 Hz except on a very few records, so never were 'stretched' much.
Regardless, I imagine in a smaller room and/or an apt. or similar, they will play loud enough for most music.
GM
Don't know, IIRC the smallest drivers I used in pipe horns were 12" and were never 'asked' to play below 40 Hz except on a very few records, so never were 'stretched' much.
Regardless, I imagine in a smaller room and/or an apt. or similar, they will play loud enough for most music.
GM
double up the drivers
There was also some talk of putting one of the drivers near the end of the line, to boost the low frequencies, but I'm not sure if there was any consensus as to where to put the driver. I had thought of trying it but went with a bipole mltl instead. Vas is still doubled in this case and you would need to low pass the second driver I believe.
There was also some talk of putting one of the drivers near the end of the line, to boost the low frequencies, but I'm not sure if there was any consensus as to where to put the driver. I had thought of trying it but went with a bipole mltl instead. Vas is still doubled in this case and you would need to low pass the second driver I believe.
FAST BiB
I'm pondering building a FAST (Fullrange ASsisTed - ie a Fullrange driver with bass reinforcement), with the bass driver in a BiB rather than the more normal sealed box or OB. I had considered going OB, but can't afford the floor space, while the BiB will stay nicely out of the way in the corner.
Given the room I'll be in, the drivers will be in the broad (depth) face of the BiB. The crossover (to a small full-ranger) will probably be in the region of 200Hz, but that is flexible and depends on the fullrange I choose anyway. The bass driver will be run from an SS amp.
I'm looking at cheap pro woofers for the bass driver, and I spotted the Fane Sovereign 8-225, which is an 8" driver with an Xmax of 5.5mm.
Fs = 62Hz
Vas = 22L = 0.777 Cu. Ft.
Qts = 0.38
Plugging those numbers into the BiB spreadsheet, I get:
L = 109"
Vb = 4.636 Cu. Ft.
Sm = 147"^2
D = 14.5"
W = 10.2"
However, I have a few questions for, well, Scott or Greg, really - although I appreciate that you have your own lives to lead.
I was wondering whether it would be feasible to lower the tuning frequency of the cabinet by lengthening the line while keeping the same footprint/mouth size.
1) Is it reasonable to increase the line length to ~140"? That's a tuning of ~48hz, which is 0.774*Fs.
2) Tuning to 44Hz (0.707*Fs, 155") is, I suppose, compromising the midbass a bit too much for a little extra extension.
I appreciate that lower tuning will reduce the low-frequency power handling and increase the ripple - and that there should be a rumble filter to prevent over-excursion below Fc. However, I am not after massively *loud* bass, so I doubt that would be a problem. I have seen comments that mention the midrange/midbass suffering when the tuning is lowered towards 0.707*Fs.
3) What is the frequency range that suffers as the length is increased? It looks to be a dip at ~250hz from some of the sims I've looked at.
Many thanks in advance,
James
I'm pondering building a FAST (Fullrange ASsisTed - ie a Fullrange driver with bass reinforcement), with the bass driver in a BiB rather than the more normal sealed box or OB. I had considered going OB, but can't afford the floor space, while the BiB will stay nicely out of the way in the corner.
Given the room I'll be in, the drivers will be in the broad (depth) face of the BiB. The crossover (to a small full-ranger) will probably be in the region of 200Hz, but that is flexible and depends on the fullrange I choose anyway. The bass driver will be run from an SS amp.
I'm looking at cheap pro woofers for the bass driver, and I spotted the Fane Sovereign 8-225, which is an 8" driver with an Xmax of 5.5mm.
Fs = 62Hz
Vas = 22L = 0.777 Cu. Ft.
Qts = 0.38
Plugging those numbers into the BiB spreadsheet, I get:
L = 109"
Vb = 4.636 Cu. Ft.
Sm = 147"^2
D = 14.5"
W = 10.2"
However, I have a few questions for, well, Scott or Greg, really - although I appreciate that you have your own lives to lead.
I was wondering whether it would be feasible to lower the tuning frequency of the cabinet by lengthening the line while keeping the same footprint/mouth size.
1) Is it reasonable to increase the line length to ~140"? That's a tuning of ~48hz, which is 0.774*Fs.
2) Tuning to 44Hz (0.707*Fs, 155") is, I suppose, compromising the midbass a bit too much for a little extra extension.
I appreciate that lower tuning will reduce the low-frequency power handling and increase the ripple - and that there should be a rumble filter to prevent over-excursion below Fc. However, I am not after massively *loud* bass, so I doubt that would be a problem. I have seen comments that mention the midrange/midbass suffering when the tuning is lowered towards 0.707*Fs.
3) What is the frequency range that suffers as the length is increased? It looks to be a dip at ~250hz from some of the sims I've looked at.
Many thanks in advance,
James
Hey folks.
Working on my first DIY project as a total audio noob, and I think I've settled on some BiB speakers.
I need to keep the whole thing, including a deeply discounted 40 watt per channel amp off of Amazon, at about $100, so I ordered these super discount speakers from madisound. Couldn't find a build using them on the forums, and I don't have measuring equipment (although there are some apps on the android market that claim to work). Anyways, here are their specs according to the datasheet:
I've also got some interesting room geometry to deal with, as you can see in the attached from-memory-and-so-not-very-accurate pictures. I believe the ceiling is lower than the 9 ft I modeled here.
It's my understanding that it's not an exact science to get the build dimensions, and that it's reasonable to tune a BiB lower than 1/2 Fs, especially if it has relatively high Qts like this one does. So I got Zilla's spreadsheet calculator (not currently up on his website, but available on this thread), and plugged in the specs for the factory Fs of 70hz and also for 50hz to give me something that comes right up to the weird corner (49" and 68" tall, respectively).
Given my tiny budget, I'll be more than happy with even decent sound out of all this, but I'd also like to get the most out of my materials. If I build the cabs tuned to 71hz (a la the calculator, so I suppose that's more like 35.5hz), I should be able to build both out of 1 4'x8' sheet of plywood/particleboard, plus a little extra for the bases. But I don't mind building them tuned to 50hz or thereabouts if it will help make sure I actually get "corner loading" at the ceiling level. Plus the tall skinny ones look cooler.
I just wanted to post to make sure I'm not totally out to lunch on this project, and whether anyone has had success with a similar set-up.
Thoughts?
Working on my first DIY project as a total audio noob, and I think I've settled on some BiB speakers.
I need to keep the whole thing, including a deeply discounted 40 watt per channel amp off of Amazon, at about $100, so I ordered these super discount speakers from madisound. Couldn't find a build using them on the forums, and I don't have measuring equipment (although there are some apps on the android market that claim to work). Anyways, here are their specs according to the datasheet:
Model NS525-255-8A
Nominal Diameter (Ø) . . . . . . . . . . . 5.25 inches (133mm)
Nominal Impedance (Z) . . . . . . . . . . 9 Ohms
Sensitivity, 1W/1m (E) . . . . . . . . . . . 89 dB @ 1 kHz
Power Capacity, RMS (Pe) . . . . . . . . 20 W
Power Capacity, Peak . . . . . . . . . . . 50 W
Frequency Range (-10dB) . . . . . . . . Fo - 6 kHz
Minimum Impedance . . . . . . . . . . . . 9 Ohms
Voice Coil Diameter (Ø) . . . . . . . . . . 25.5 mm
Voice Coil Winding Length (h) . . . . . 12 mm
Voice Coil Number of Layers
Voice Coil Former Material . . . . . . . . Kapton
Voice Coil Wire Composition . . . . . . Copper
Motor Reference . . . . . . . . . . . . . . . N255-C08-127A
Magnetic Material . . . . . . . . . . . . . . Neodymium radial
Stray Flux Shielding . . . . . . . . . . . . . Inherent
Magnetic Gap Depth (He) . . . . . . . . 12.7 mm
Cone Material . . . . . . . . . . . . . . . . . Paper
Surround Material . . . . . . . . . . . . . . Foam
Polarity, Outward Motion . . . . . . . . . Positive voltage on (+) tab
Net Weight . . . . . . . . . . . . . . . . . . . . 0.458 kg
Thiele / Small Parameters
Resonant Frequency (Fo) - Fs . . . . . 70 Hertz
Voice Coil DC Resistance - Re . . . . . 7.4 Ohms
Total Q - Qts . . . . . . . . . . . . . . . . . . 0.55
Mechanical Q - Qms . . . . . . . . . . . . 11
Electrical Q - Qes . . . . . . . . . . . . . . 0.58
Equivalent Volume of Air - Vas . . . . . 8.00 L
Radiating Piston Area - Sd . . . . . . . . 89.00 cm2
Electrical / Mechanical Parameters
Flux Density x Length - BL . . . . . . . . 6.35 Tesla-meters
Compliance - Cms . . . . . . . . . . . . . . 750 mm/N
Total Mass - Mms . . . . . . . . . . . . . . 7.0 grams
I've also got some interesting room geometry to deal with, as you can see in the attached from-memory-and-so-not-very-accurate pictures. I believe the ceiling is lower than the 9 ft I modeled here.
It's my understanding that it's not an exact science to get the build dimensions, and that it's reasonable to tune a BiB lower than 1/2 Fs, especially if it has relatively high Qts like this one does. So I got Zilla's spreadsheet calculator (not currently up on his website, but available on this thread), and plugged in the specs for the factory Fs of 70hz and also for 50hz to give me something that comes right up to the weird corner (49" and 68" tall, respectively).
Given my tiny budget, I'll be more than happy with even decent sound out of all this, but I'd also like to get the most out of my materials. If I build the cabs tuned to 71hz (a la the calculator, so I suppose that's more like 35.5hz), I should be able to build both out of 1 4'x8' sheet of plywood/particleboard, plus a little extra for the bases. But I don't mind building them tuned to 50hz or thereabouts if it will help make sure I actually get "corner loading" at the ceiling level. Plus the tall skinny ones look cooler.
I just wanted to post to make sure I'm not totally out to lunch on this project, and whether anyone has had success with a similar set-up.
Thoughts?
Attachments
I'm pondering building a FAST (Fullrange ASsisTed - ie a Fullrange driver with bass reinforcement), with the bass driver in a BiB rather than the more normal sealed box or OB. I had considered going OB, but can't afford the floor space, while the BiB will stay nicely out of the way in the corner.
Given the room I'll be in, the drivers will be in the broad (depth) face of the BiB. The crossover (to a small full-ranger) will probably be in the region of 200Hz, but that is flexible and depends on the fullrange I choose anyway. The bass driver will be run from an SS amp.
I'm looking at cheap pro woofers for the bass driver, and I spotted the Fane Sovereign 8-225, which is an 8" driver with an Xmax of 5.5mm.
Fs = 62Hz
Vas = 22L = 0.777 Cu. Ft.
Qts = 0.38
Plugging those numbers into the BiB spreadsheet, I get:
L = 109"
Vb = 4.636 Cu. Ft.
Sm = 147"^2
D = 14.5"
W = 10.2"
However, I have a few questions for, well, Scott or Greg, really - although I appreciate that you have your own lives to lead.
I was wondering whether it would be feasible to lower the tuning frequency of the cabinet by lengthening the line while keeping the same footprint/mouth size.
1) Is it reasonable to increase the line length to ~140"? That's a tuning of ~48hz, which is 0.774*Fs.
2) Tuning to 44Hz (0.707*Fs, 155") is, I suppose, compromising the midbass a bit too much for a little extra extension.
I appreciate that lower tuning will reduce the low-frequency power handling and increase the ripple - and that there should be a rumble filter to prevent over-excursion below Fc. However, I am not after massively *loud* bass, so I doubt that would be a problem. I have seen comments that mention the midrange/midbass suffering when the tuning is lowered towards 0.707*Fs.
3) What is the frequency range that suffers as the length is increased? It looks to be a dip at ~250hz from some of the sims I've looked at.
Many thanks in advance,
James
You’re welcome!
Bummer, ‘FAST’ and ‘sub’ systems were the only way I’ve used pipe horns, but to date, no one has been willing to try one AFAIK. Oh well, maybe the answers will be of some help to others.
The standard BIB tuning is an octave lower [0.5*Fs] and I've tuned lower to get a pipe to the ceiling or to another corner when laid down to form an audio system platform, though of course these need to be corner loaded to provide at least some driver protection plus I mass loaded [vented] them a bit by using a vent area [Av] = driver effective piston area [Sd].
1, 2) A horn’s fundamental is 1/4 WL, so 140"/155" = ~ 24/22 Hz pipe tuning [Fp]. The 0.707*Fs limit is mine for most reflex [ML] alignments until either the Fs gets low enough for room gain to help protect the driver and/or it has a high Qts, ergo high Qts drivers are ideal for TLs in general and pipe horns in particular.
FWIW, D.B. Keele's extended bass shelf [EBS] alignment specs a ~0.6579*Fs tuning with a 0.625 effective Qts.
3) Like any undersized, low tuned alignment, F3 rises, but if there's good room loading, this is mostly moot; otherwise, mass loading it solved the problem good enough for me and the folks I made them for.
The major dip is at the pipe’s 3rd harmonic, which equates to ~ 1 WL [~ 2 octaves] away from Fp, i.e. a ~20 Hz Fp = ~ 80 Hz dip.
GM
Greets!
There’s relative little extra boundary loading until it’s nearing perpendicular, so you might want to consider flipping them to corner floor loaded.
GM
Thanks for the detailed answer - it certainly clarifies things in my head somewhat.
I'm still planning a FAST system, but had chosen a different midbass driver (the Monacor SPH-210) with an Fs of 28Hz, so tuning below Fs was no longer a problem. The line was to be 170" for an Fp of ~20Hz.
That said, with your reply I'm now wondering whether to stay with the Fane: it does have a slightly higher Qts (0.38 rather than 0.24) and quite a bit more Xmax (5.5mm Vs 3.5mm) - along with a smaller Vas. It's cheaper and more efficient, too.
The Fane, tuned to Fp=31Hz=0.5*Fs, gives a box with a rounded-off footprint of 11.5" by 15.5", and a line of 110". IIRC, when extending the line you suggest keeping the same footprint - after all, more Vb can't hurt (again IIRC). Extend it out to 170" line to give an Fp of 20Hz and a box height of 7'2" (I have 9'9" ceilings here, so that's still 31" away), corner-load it, mass load with Av=Sd, and high-pass it at ~20Hz.
By the way, I'm planning to cross-over actively at 400Hz to a Fostex FF105WK in a ~2.5L sealed box. Conveniently, the 11.5" wide (external) cabinet that I got for either driver has a baffle step at about, oh, 400Hz - so any correction required can be done by altering the gain of the bass amp.
I appreciate that the BiB is unlikely to need much, if any, BSC, but it's nice to have the option of such a simple correction, especially given those high ceilings.
Don't know, but IIRC Markaudio has some concerns about some types of cab alignments, so best to check with them.
GM
Mark's concern is the potential of running his drivers too low too hard. If they are used sealed, then the box will prevent over excursion except when the user is being really stupid with the volume knob. However, I have a MLTL for the A10.2 that has f3@40 and F10@30. By 30Hz, the cabinet is unloading in a hurry and too aggressive bass boost or high volume will easily damage the cone. I would think that a BiB would cause the same concern. OB's pose even more danger, but most users will high pass the driver well above the danger zone.
Bob
Bob
You’re welcome!
Run them both in a reflex calculator tuned to whatever Fb you’d like, add some series resistance to match up Qes, Qts to see which one has the best power handling and/or if the higher price can be justified.
Right, there’s never too much horn acoustic efficiency, just a point of diminishing returns WRT size, but when going vertical it doesn’t seem that much bigger, quite the opposite as its visual aspect ratio narrows.
Hmm, IIRC, never did any where it was far away from the ceiling or corner if laying down, so no clue how this scenario will pan out, but ‘discretion being the better part of valor’, starting out high on the hi-pass seems a good plan if you’re going to use them for pipe organ symphonies, movies or similar.
When I was building them, the hi-pass was for TT ‘rumble’ as there was no commercially available music with any loud content below ~40 Hz, so a 20-27 Hz tuning was just for picking up the rolled off deep bass of a few recordings and the pipe horns added enough gain to add a bit of ‘fullness’ to make it sound more natural/life-like.
Anyway, looking forward to what you come up with and whether or not it meets your expectations.
GM
Bob,
I have the drivers on my BIB originally for FE168EZ. It works wonderful and goes pretty low. I didn't try on highest volume yet and surely try this after the break in period.
Albert
BIB is a forgiving cabinet. I think you can just about pop any driver into it and it will work. The BIB will immediately reveal the character of the driver being used. For example, the Fostex 127e sounded delicate and sweet while the Dayton 5” full ranger sounded bold and full. These drivers have totally different specs but their personalities shined thru in BIBs… and to be honest, even tho the cabinet was designed to work with the 127e I prefer the Dayton in the same cab (which the BIB calculator configured a totally different set of dimensions). If anything, the Dayton is too bassy but nothing unpleasant or bloated… just a bit bassy. I’ve become curious about double mouthed horns lately. I’d imagine they’ll have their own set of pros and cons… and look forward to finding out.