Greetings Everyone,
I've been intensely curious to hear the BIBs ever since first reading about them, so when I retrieved this pair of Fostex FE164-s from storage I decided to go for it. I bought these on closeout a few years ago; the FE164 (featured in Martin's Project 2) is essentially similar to its successor, the FE167E, but with more excursion and slightly lower high end (Xmax is 1.0, high freq is 20K), so it should fit the box nicely.
But now after doing a BIB search of the forum, I wonder which one? Scottmoose, I certainly appreciate the abundant fruits of your R&D with the design that you've laid on us so far, and I wonder: Have you built and listened to one or more of the alternative boxes you suggested for the Sigma and such about a month ago, and/or do you have a theoretical favorite among them at this point? Anybody else? What might you do with a pair of FE164-s?
Thanks All,
Don
I've been intensely curious to hear the BIBs ever since first reading about them, so when I retrieved this pair of Fostex FE164-s from storage I decided to go for it. I bought these on closeout a few years ago; the FE164 (featured in Martin's Project 2) is essentially similar to its successor, the FE167E, but with more excursion and slightly lower high end (Xmax is 1.0, high freq is 20K), so it should fit the box nicely.
But now after doing a BIB search of the forum, I wonder which one? Scottmoose, I certainly appreciate the abundant fruits of your R&D with the design that you've laid on us so far, and I wonder: Have you built and listened to one or more of the alternative boxes you suggested for the Sigma and such about a month ago, and/or do you have a theoretical favorite among them at this point? Anybody else? What might you do with a pair of FE164-s?
Thanks All,
Don
Hi Don
I completed the latest pair last week. They were for a friend over in Sheffield actually, and were enlarged boxes to take (wait for it...) the FF225K. The very last driver you'd expect to work. Except for the fact that they did. Rather well. I didn't hear them with added super-tweeters, which their new ower is adding to take response up past 14Khz, but with 30AWG wire and a tube-amp, they were stunning. Didn't go lower than the smaller drivers, but one of the largest soundstages I've ever heard.
Hmm, FE164. Right, couple of options. Terry's original box should work fine. Plenty of people have used just that to good effect. However, quite a few FE168ESigma owners have commented that they love it, but would enlarge things a bit if they did it again. As the originals were designed for smaller drivers, this is not surprising. They are very forgiving, and should work well, but increasing some dimensions should reap some rewards. Now, the FE164, 166 / 167, despite their smaller frame, actually have a larger cone area then the Sigmas -20.56in^2 if memory serves, so they too should benefit a bit. So, this is what I would do for the 164/6/7 family (the FF165K needs a slightly longer line) assuming 3/4" build material. I don't have the original design equations etc, as I can't get hold of those Fostex Craft Manuals (try though I have), but I'm pretty sure I'm about right here, and I'm sure Terry or an owner of the manuals would straighten us out if I'm off:
External dimensions:
Height: 64"
Width: 7"
Depth 18"
Driver 28 1/2" from the top
Internal baffle ends 7 14/16" from the floor and internal front & rear baffle walls.
Stuff the point lightly, and add a layer to the base of the cabinet. Shove against a rear wall, or better, into corners. If you've an SS amp, you'll need at least 24AWG wire.
My own pair of BIB cabinets have FF165Ks. Enclosure width and depth are the same as suggested above, but with Terry's original 70" cabinet height and driver positioned 31" from the top as they have a lower Fs. Still not long enough theoretically, but I won't go taller than 70" otherwise the driver will be well above the listening height, unless you listen sitting on a bar-stool of course... To say they thunder would be a chronic understatement. Allison Goldfrapp never sounded so sexy either.
Hope some of this helps.
Scott
I completed the latest pair last week. They were for a friend over in Sheffield actually, and were enlarged boxes to take (wait for it...) the FF225K. The very last driver you'd expect to work. Except for the fact that they did. Rather well. I didn't hear them with added super-tweeters, which their new ower is adding to take response up past 14Khz, but with 30AWG wire and a tube-amp, they were stunning. Didn't go lower than the smaller drivers, but one of the largest soundstages I've ever heard.
Hmm, FE164. Right, couple of options. Terry's original box should work fine. Plenty of people have used just that to good effect. However, quite a few FE168ESigma owners have commented that they love it, but would enlarge things a bit if they did it again. As the originals were designed for smaller drivers, this is not surprising. They are very forgiving, and should work well, but increasing some dimensions should reap some rewards. Now, the FE164, 166 / 167, despite their smaller frame, actually have a larger cone area then the Sigmas -20.56in^2 if memory serves, so they too should benefit a bit. So, this is what I would do for the 164/6/7 family (the FF165K needs a slightly longer line) assuming 3/4" build material. I don't have the original design equations etc, as I can't get hold of those Fostex Craft Manuals (try though I have), but I'm pretty sure I'm about right here, and I'm sure Terry or an owner of the manuals would straighten us out if I'm off:
External dimensions:
Height: 64"
Width: 7"
Depth 18"
Driver 28 1/2" from the top
Internal baffle ends 7 14/16" from the floor and internal front & rear baffle walls.
Stuff the point lightly, and add a layer to the base of the cabinet. Shove against a rear wall, or better, into corners. If you've an SS amp, you'll need at least 24AWG wire.
My own pair of BIB cabinets have FF165Ks. Enclosure width and depth are the same as suggested above, but with Terry's original 70" cabinet height and driver positioned 31" from the top as they have a lower Fs. Still not long enough theoretically, but I won't go taller than 70" otherwise the driver will be well above the listening height, unless you listen sitting on a bar-stool of course... To say they thunder would be a chronic understatement. Allison Goldfrapp never sounded so sexy either.
Hope some of this helps.
Scott
One other thought -a suggestion I remember Terry himself making a while back elsewhere for the FE164. This driver can benefit from the whizzer cone being removed -better soundstage depth, imaging, width, loss of that annoying shout the cones always seem to have, without damage to the top end apparantly. Then you could add Dave's phase plugs. If that's a bridge too far, you could trim the whizzer back in stages, 1/4" at a time. Bit drastic, but could be worth doing.
Scott
Scott
Scottmoose said:
All of it helps. Thank you.
And well, that is one sure way to eliminate the whizzer cone problem, isn't it? I knew I'd get to some of the latest driver mods, certainly phase plugs, before I got them into the boxes. I seem to remember an ancient one called "the 99 cent FE164 mod" or something like that, maybe using rope caulk...? Anyway I'm delighted to hear of this whizzer cone solution, and I'm sure I'm up for it (let's see now, the whizzer cone is this one, right? ;-)
Another subject, has anyone addressed the sizing, and effectiveness or not, of the circular false baffle? Do you use it?
Oh dear. I did hope you wouldn't ask that. However, seeing that you have...
There was a thread, oh, maybe 6 or more (probably more) months back where we debated this issue, which ended up being rather... spirited, shall we say? I've pretty much stayed on the fence with this one. I have not tried them myself, primarily because a) I don't own, and cannot in the foreseeable future afford a lathe, and also because getting hold of a decent hardwood in the UK is like finding someone over here who knows how to cook a decent steak -rare. (Sorry about that!) So I can't comment from personal experience, though I'll try to offer a quick, objective critique of the situation. The problem we have here is that, just like the BIB boxes themselves, there isn't any software that can actually model these baffles in-room behaviour yet; at least, not to the best of my knowledge and I do try to keep up to date. Oh, there's several programs that allow you to model flat baffles of various shapes and sizes, but not baffles with a constantly varying radii like those Terry creates. Now, the effect of flat baffles (especially circular) sticking out beyond the edges of an enclosure is invariably not pretty in my experience. They are A Very Bad Idea then in my view, and I have seen nothing thus far that makes me even contemplate altering this stance. However, these baffles Terry creates are, as noted above, not flat. Far from it. Does this make a difference? Well, there are two questions here: 1) Do they damage the sound, and 2) Do they bring any benefits to the sound.
Looking at the response plot of the Abby at 1m as measured by Nelson Pass on his First Watt article on current-source amps and full-range drivers, I can't see anything at all that looks like a problem caused by the baffle being there, in contrast to what programs like The Edge suggest would happen if a flat baffle of identical diameter (I think it's circa 11 1/2", give or take) was there. So in answer to question 1), they certainly don't appear to be damaging the sound or causing any problems.
Question 2) is the trickier bit though. Do they improve things? Well, it's not inconcievable. If we look at Nelson's measured response of the Abby again, do you spot any sign of real baffle-step problems? No, I don't either, which is rather unusual for a tall, 9" wide cabinet with no compensation network and no active Eq (so far as I know) being applied. Which leads us to 2 possibilities. Either the cabinets were slammed up hard against a rear wall, or these little baffles were helping out a bit (or both of course). Now personally, I would've thought these podular baffles were too small to assist in this respect, but equally, I cannot see how this narrow cabinet alone could have such negigable baffle-step issues without some assistance. So it's certainly possible they help in this regard. I'll keep an open mind on this one, until someone takes some definitive measurements of two otherwise identical cabinets, one with baffles in place, and the other without.
What also intrigues me are comments suggesting that these baffles of Terry's assist in image projection etc., and it's here that the debate seems to be hottest. I see no reason to doubt the comments, but I'm always wary of purely subjective views too -if there's a difference you can measure it. (Of course, we then have to qualify this by noting that we have to know what we are supposed to be looking for in measurements, and more particularly how we are actually going to carry these measurements out. Not always as easy as people think.) Assuming they are not convincing themselves they are hearing something that isn't really there, I can offer a couple of possible explanations for this effect. Firstly, it could well have something to do with edge diffraction, and they might perhaps be dispersing some of the nasties seen here. I'm not an expert, and again, they seem rather small to my way of thinking for achieving this end, but this would go some way toward explaining it. Another, rather more obscure possibility could be that they might help negate, or perhaps again disperse, reflections off the driver surround, which is an eternal issue with all moving coil drivers. Again, sheet speculation on my part.
Conclusions? Well, for what it's worth, in my oppinion, you should under no circumstances attempt to use a flat, circular baffle. That will do things to the sound, and none of them are attractive. You'd be much better off doing without. If you're good with the old lathe, then you've nothing to loose by giving it a shot though. If you don't like them, you can always remove them after all, and you might get some benefits.
Cheers
Scott
PS -I'd go for Dave's phase-plugs as the first modification the 164s. You could try the whizzer-cone reduction / removal thing afterwards.
There was a thread, oh, maybe 6 or more (probably more) months back where we debated this issue, which ended up being rather... spirited, shall we say? I've pretty much stayed on the fence with this one. I have not tried them myself, primarily because a) I don't own, and cannot in the foreseeable future afford a lathe, and also because getting hold of a decent hardwood in the UK is like finding someone over here who knows how to cook a decent steak -rare. (Sorry about that!) So I can't comment from personal experience, though I'll try to offer a quick, objective critique of the situation. The problem we have here is that, just like the BIB boxes themselves, there isn't any software that can actually model these baffles in-room behaviour yet; at least, not to the best of my knowledge and I do try to keep up to date. Oh, there's several programs that allow you to model flat baffles of various shapes and sizes, but not baffles with a constantly varying radii like those Terry creates. Now, the effect of flat baffles (especially circular) sticking out beyond the edges of an enclosure is invariably not pretty in my experience. They are A Very Bad Idea then in my view, and I have seen nothing thus far that makes me even contemplate altering this stance. However, these baffles Terry creates are, as noted above, not flat. Far from it. Does this make a difference? Well, there are two questions here: 1) Do they damage the sound, and 2) Do they bring any benefits to the sound.
Looking at the response plot of the Abby at 1m as measured by Nelson Pass on his First Watt article on current-source amps and full-range drivers, I can't see anything at all that looks like a problem caused by the baffle being there, in contrast to what programs like The Edge suggest would happen if a flat baffle of identical diameter (I think it's circa 11 1/2", give or take) was there. So in answer to question 1), they certainly don't appear to be damaging the sound or causing any problems.
Question 2) is the trickier bit though. Do they improve things? Well, it's not inconcievable. If we look at Nelson's measured response of the Abby again, do you spot any sign of real baffle-step problems? No, I don't either, which is rather unusual for a tall, 9" wide cabinet with no compensation network and no active Eq (so far as I know) being applied. Which leads us to 2 possibilities. Either the cabinets were slammed up hard against a rear wall, or these little baffles were helping out a bit (or both of course). Now personally, I would've thought these podular baffles were too small to assist in this respect, but equally, I cannot see how this narrow cabinet alone could have such negigable baffle-step issues without some assistance. So it's certainly possible they help in this regard. I'll keep an open mind on this one, until someone takes some definitive measurements of two otherwise identical cabinets, one with baffles in place, and the other without.
What also intrigues me are comments suggesting that these baffles of Terry's assist in image projection etc., and it's here that the debate seems to be hottest. I see no reason to doubt the comments, but I'm always wary of purely subjective views too -if there's a difference you can measure it. (Of course, we then have to qualify this by noting that we have to know what we are supposed to be looking for in measurements, and more particularly how we are actually going to carry these measurements out. Not always as easy as people think.) Assuming they are not convincing themselves they are hearing something that isn't really there, I can offer a couple of possible explanations for this effect. Firstly, it could well have something to do with edge diffraction, and they might perhaps be dispersing some of the nasties seen here. I'm not an expert, and again, they seem rather small to my way of thinking for achieving this end, but this would go some way toward explaining it. Another, rather more obscure possibility could be that they might help negate, or perhaps again disperse, reflections off the driver surround, which is an eternal issue with all moving coil drivers. Again, sheet speculation on my part.
Conclusions? Well, for what it's worth, in my oppinion, you should under no circumstances attempt to use a flat, circular baffle. That will do things to the sound, and none of them are attractive. You'd be much better off doing without. If you're good with the old lathe, then you've nothing to loose by giving it a shot though. If you don't like them, you can always remove them after all, and you might get some benefits.
Cheers
Scott
PS -I'd go for Dave's phase-plugs as the first modification the 164s. You could try the whizzer-cone reduction / removal thing afterwards.
DMD said:
Greets!
Never heard of this one, but there's the '$0.98 Mod' originally posted to tame the Lowther's whizzer, which of course works on any whizzer since its primary/secondary function is to damp the comb filtering between the whizzer and main diaphragm and mildly damp its bell modes: http://web.archive.org/web/20020628234451/http://www.mindspring.com/~darmah/lowther/mods.htm
Use rope caulk on the inside/outside of the basket and all the motor to damp it as well as reduce reflections. Anchor wires to keep them from 'singing'.
GM
Sounds good to me, and slightly less drastic too! Any thoughts regarding the box dimensions to share Greg?
Cheers
Scott
Cheers
Scott
DMD said:
Greets!
Flat baffles will work well enough if cut into an amorphous shape to average out its eigenmodes (standing waves). Its area plus end correction plus some percentage of the main baffle's area will define its F3 baffle step point. Make it big enough to blend into the room's boundary gain and no electronic BSC is required, ergo its size is room/location/desired f3 dependent. If you're convinced any HF reflections off its sharp or modestly rounded edge are degrading imaging/soundstaging/whatever, trim it with fairly dense open cell foam, or for SAF centric audiophiles, have the S.O. make/have made some nice quilted edge covers for them in whatever pattern/colors suits their fancy and finish off the cabs in whatever complementary color/stain/whatever they choose.
Note that both these edge treatments (or similar) will negate the need for an amorphous shape, so a simple round baffle suffices, which is theoretically best since 'sound is round'.
WRT the baffle's curvature, its performance goal is to negate the need for any edge damping and a theoretically mathmatically 'perfect' decreasing radius can be derived from J.M. LeCleach's horn mouth expansion routine, which will have a rolled over flange if carried to completion, but a simple radius = the baffle's diameter suffices down in the midbass/lower mids IMO.
WRT the baffle's sonic effect other than lowering the baffle step corner, it's a passive radiator, with radiation patterns of a rigid piston of whatever curvature it has and it further mass loads the driver, so of course it will audibly affect imaging/soundstaging to some extent, and all for the better if its eigenmodes and transition from driver to baffle acoustic impedance mismatches are well damped, so I don't understand why there would be any debate, especially 'heated', per se on this subject.
If there's a debate buried in this subject, it's the potentially audible difference between a narrow baffle's smaller BSC filter's component values and greater dynamic headroom loss Vs a larger one's. I would think that the difference wouldn't be subtle even with 'top drawer' ($$$) components. Since I don't like giving up any dynamic headroom for any reason other than sheer lack of $$$ and/or space, I do whatever it takes to avoid the issue as much as practical, but I can see why folks with small rooms, sitting fairly close to their speakers would find narrow baffles and maybe some BSC acceptable if they have adequate amp power.
Specific to the Abby, if the baffle has a 11.5" diameter, then its effective radiation diameter is ~11.5+((11.5/2)*0.613) = ~15" plus whatever % area the main baffle contributes to its effective diameter, so its F3 will be somewhere below ~13560"/pi/15" = ~287 Hz. NP's Abby measurements show a baffle step corner below this frequency and no high Q peaks/dips in the midbass/mids response due to eigenmodes, so there's at least one measurement 'proof' that the 'small' curved round baffle is more than just a 'pretty face'. 😉
GM
Well, there you have it. Thanks for that Greg. I didn't think I could see any significant response problems on NPs Abby measurements over circa 250Hz; nice to have some confirmation that I'm not going blind. It will, however, take me some time to digest all of the implications of that post -I can't recall the last time I read one without learning something or it forcing me to spend even more time with the literature. Fine with me though. As I say, I don't pretend to be an expert, and I stayed firmly on the fence when these things cropped up a few months back, but there was a certain amount of... friction that emerged. This is the thread I was thinking of: http://www.diyaudio.com/forums/showthread.php?s=&threadid=55416&highlight=
Not having any hard facts to make any decisions by, I didn't really pursue matters other than having a suspicion that there could be something in it, but I'd do without until I learned some more. Thanks for clearing some of that up!
I assume that's why several of your MLTL designs (the MLTL48 for the Jordans, say) are wider than they are deep? I built a pair of MJKs MLTLs with FE207Es a few months back with 6" extensions on each side (the internal line was unchanged as I kept the original side-walls) to try out the effects of wide-baffles and came away impressed. Bit too large for my room in terms of their width, but instructive -BSC requirements were negligable to the point of not required, and I did like the overall presentation, which did sound like it had some of the benefits of dipoles.
Cheers
Scott
Not having any hard facts to make any decisions by, I didn't really pursue matters other than having a suspicion that there could be something in it, but I'd do without until I learned some more. Thanks for clearing some of that up!
I assume that's why several of your MLTL designs (the MLTL48 for the Jordans, say) are wider than they are deep? I built a pair of MJKs MLTLs with FE207Es a few months back with 6" extensions on each side (the internal line was unchanged as I kept the original side-walls) to try out the effects of wide-baffles and came away impressed. Bit too large for my room in terms of their width, but instructive -BSC requirements were negligable to the point of not required, and I did like the overall presentation, which did sound like it had some of the benefits of dipoles.
Cheers
Scott
What a banquet of info I just sat down to. Very much appreciated, Scott and GM.
Yes, the 98 cent foam strip mod does sound like a more 'civilized' way of dealing with the whizzer cone (cheaper than I remembered, too! ;–)
I make elegant sense out of what GM says re the baffle, though off the top of my head I don't know the precise practical steps in making it, as he said, big enough to blend into the room's boundary gain; I'll research that in the morning.
Here's an off the wall question, if you'll excuse the worthless pun, since we're loading the ceiling with this box: I wonder how significant a change in the quantity and quality of bass is produced by changes in the distance between the top of the box and the ceiling, both on account of shorter/taller box dimensions and of lower/higher ceilings?
Yes, the 98 cent foam strip mod does sound like a more 'civilized' way of dealing with the whizzer cone (cheaper than I remembered, too! ;–)
I make elegant sense out of what GM says re the baffle, though off the top of my head I don't know the precise practical steps in making it, as he said, big enough to blend into the room's boundary gain; I'll research that in the morning.
Here's an off the wall question, if you'll excuse the worthless pun, since we're loading the ceiling with this box: I wonder how significant a change in the quantity and quality of bass is produced by changes in the distance between the top of the box and the ceiling, both on account of shorter/taller box dimensions and of lower/higher ceilings?
And i was wondering if you could just flip the cabinet over, raise it 5" to 10" and load the floor?
My basement ceilings are about 6" lower than normal and might not work right. Loading the floor might remove this variable.
Godzilla
My basement ceilings are about 6" lower than normal and might not work right. Loading the floor might remove this variable.
Godzilla
Good questions. Actually, it's not quite as significant as you might believe. Whilst you do drive the room's vertical resonant mode with these boxes, Martin says it isn't quite as simple as that. These things need to be pushed against a rear wall, or better, into corners to give of their best, right? But surely if they were driving the vertical mode alone, that shouldn't be as much of a factor.
The reason they work, as I understand it, is down to the position of what is effectively a horn-mouth on the top of the cabinet. I'll quote verbatim here as Martin can communicate ideas like this more lucidly that I could ever hope to. This was in response to a question I had asked about why these things have such terrible computer sim results, yet usually measure way better in-room.
First, with the open end backed up against the wall the effective mouth area is doubled, due to the reflection boundary condition at the wall, and this will allow lower frequencies to be more efficiently transferred into the room (the resistive portion of the acoustic impedance is doubled). At the same time, less energy is reflected back into the line reducing the magnitude of the standing waves. So more bass output and attenuated standing waves compared to the simulation results.
Second, by pointing the open end up you are listening over 90 degrees off axis. With the mouth output reflected off the wall, the depth dimension effectively doubles while the width remains the same. This shape is going to become very directional with increasing frequency so the ragged response predicted above say 300 Hz is probably grossly over estimated.
So, it's not so much the vertical mode as the position of the mouth in relation to a room-boundary in the form of a nice vertical wall that is the most significant factor at work here, bit like a corner horn. In my own experience, the height of the room and the cabinet in relation to it can make a difference, but it's more to do with the quantity, rather than the depth, of bass output. Lower rooms seem to make for more weight in the bass, though at slightly different points, but don't tend to affect the bass-depth very much. You also have to consider the drivers you are loading the cabinet with, the amplifier's damping or lack thereof, and the resitance of the wire you are using. I recall Terry telling me of a pair of these things he built using FE168Sigmas (pre ESigma model I believe) a few years back that now reside in alcoves in their new owners' living room. Apparantly, it would be too much bass except there is no boom at all, so it doesn't damage the rest of the frequency range.
Flipping the boxes might work -not sure on that, chances are you'd be reducing the bass-output a bit as there wouldn't be enough space to reflect the mouth properly. Also, a box this heavy on spacers that tall might not be overly stable. 'Zilla -what drivers were you thinking about using? Chances are, you'd probably be fine with a slightly shorter cabinet if you were still concerned about room-height.
Cheers
Scott
The reason they work, as I understand it, is down to the position of what is effectively a horn-mouth on the top of the cabinet. I'll quote verbatim here as Martin can communicate ideas like this more lucidly that I could ever hope to. This was in response to a question I had asked about why these things have such terrible computer sim results, yet usually measure way better in-room.
First, with the open end backed up against the wall the effective mouth area is doubled, due to the reflection boundary condition at the wall, and this will allow lower frequencies to be more efficiently transferred into the room (the resistive portion of the acoustic impedance is doubled). At the same time, less energy is reflected back into the line reducing the magnitude of the standing waves. So more bass output and attenuated standing waves compared to the simulation results.
Second, by pointing the open end up you are listening over 90 degrees off axis. With the mouth output reflected off the wall, the depth dimension effectively doubles while the width remains the same. This shape is going to become very directional with increasing frequency so the ragged response predicted above say 300 Hz is probably grossly over estimated.
So, it's not so much the vertical mode as the position of the mouth in relation to a room-boundary in the form of a nice vertical wall that is the most significant factor at work here, bit like a corner horn. In my own experience, the height of the room and the cabinet in relation to it can make a difference, but it's more to do with the quantity, rather than the depth, of bass output. Lower rooms seem to make for more weight in the bass, though at slightly different points, but don't tend to affect the bass-depth very much. You also have to consider the drivers you are loading the cabinet with, the amplifier's damping or lack thereof, and the resitance of the wire you are using. I recall Terry telling me of a pair of these things he built using FE168Sigmas (pre ESigma model I believe) a few years back that now reside in alcoves in their new owners' living room. Apparantly, it would be too much bass except there is no boom at all, so it doesn't damage the rest of the frequency range.
Flipping the boxes might work -not sure on that, chances are you'd be reducing the bass-output a bit as there wouldn't be enough space to reflect the mouth properly. Also, a box this heavy on spacers that tall might not be overly stable. 'Zilla -what drivers were you thinking about using? Chances are, you'd probably be fine with a slightly shorter cabinet if you were still concerned about room-height.
Cheers
Scott
Hi Scott!
I would use the older FE168Sigma i have now playing in ported boxes. 24 Liter... sounds nice.
(Server needs to be reboot so may be very slow to load today)
http://www.zillaspeak.com/zillaspeakfostex24L168.asp
My plan is to pull the drivers out and plop them into Straight Pipes i built... but my pipes are 8" wide inner dims (everything else the same - see Bob's sight below) to accomodate the driver.
http://www.geocities.com/rbrines1/Pages/Straight_Pipe.html
I think these boxes would work well with the 168S but have to try it and see.
But i was wondering about the BIB.
Peace,
Godzilla
I would use the older FE168Sigma i have now playing in ported boxes. 24 Liter... sounds nice.
(Server needs to be reboot so may be very slow to load today)
http://www.zillaspeak.com/zillaspeakfostex24L168.asp
My plan is to pull the drivers out and plop them into Straight Pipes i built... but my pipes are 8" wide inner dims (everything else the same - see Bob's sight below) to accomodate the driver.
http://www.geocities.com/rbrines1/Pages/Straight_Pipe.html
I think these boxes would work well with the 168S but have to try it and see.
But i was wondering about the BIB.
Peace,
Godzilla
Hey 'Zilla
You know, the BIB box, and Bob's straight pipes are the very first cabinets that got me interested in DIY hifi a couple of years back. I didn't build either, but they provided some inspiration to start looking further until I finally came back to Terry's big folded horn / TQWT a few months ago.
Non 'E' 168Sigma? Nice driver. The dims I suggested for the FE164/6/7 should work OK, but as the Sigmas' Sd is a little smaller you could reduce the cabinet a bit. Try this for a BIB box for them (assuming 3/4" build material is used, and should work for the ESigma too by my reckoning):
64" height (Increase to 66 1/2" for the Esigma)
15 3/4" depth (external)
7" width (external)
Driver 28 1/2" from cabinet top (29" from the top for ESigma)
End the internal baffle 6 3/4" from the cabinet base and 6 3/4" from the internal front and rear cabinet walls.
That could be a really good combination. Only problem of course is that you would need to add a baffle like Terry's a) to assist with baffle-step, though with them rammed against a rear wall or in corners that shouldn't matter as much, and more particularly b) the driver is actually about 1/2" too wide to fit! If the additional baffle's a problem, then you could increase the external width to 8", reduce the external depth to 13 3/4", and terminate the internal baffle 5 3/4" from the floor and the internal front and rear baffle walls.
I like those vented boxes though BTW.
Cheers
Scott
You know, the BIB box, and Bob's straight pipes are the very first cabinets that got me interested in DIY hifi a couple of years back. I didn't build either, but they provided some inspiration to start looking further until I finally came back to Terry's big folded horn / TQWT a few months ago.
Non 'E' 168Sigma? Nice driver. The dims I suggested for the FE164/6/7 should work OK, but as the Sigmas' Sd is a little smaller you could reduce the cabinet a bit. Try this for a BIB box for them (assuming 3/4" build material is used, and should work for the ESigma too by my reckoning):
64" height (Increase to 66 1/2" for the Esigma)
15 3/4" depth (external)
7" width (external)
Driver 28 1/2" from cabinet top (29" from the top for ESigma)
End the internal baffle 6 3/4" from the cabinet base and 6 3/4" from the internal front and rear cabinet walls.
That could be a really good combination. Only problem of course is that you would need to add a baffle like Terry's a) to assist with baffle-step, though with them rammed against a rear wall or in corners that shouldn't matter as much, and more particularly b) the driver is actually about 1/2" too wide to fit! If the additional baffle's a problem, then you could increase the external width to 8", reduce the external depth to 13 3/4", and terminate the internal baffle 5 3/4" from the floor and the internal front and rear baffle walls.
I like those vented boxes though BTW.
Cheers
Scott
Scottmoose said:
Yes, that MJK stuff was beautiful, wasn't it?
I really can't thank you enough for your invaluable experiential input (not to mention everything else). I'm a zillion steps past where I would have been without it.
I read that before and it made my hair stand on end.
And from my own perspective, I think I'd be missing a good part of the fun if I flipped them over; for some reason I'm inordinately fond of the fact that these fire up.
Now regarding the issue of the spouse-pending-approval factor and "the donut," as she currently refers to the prospective round baffle:
From what I've gathered so far, the way to get a figure worth figuring for room gain is to measure it; I thought there might be a formula using room dimensions, but apparently there are too many other powerful influences to make that workable. (If I'm mistaken, of course, somebody please correct me). So I think that I'll plan on sizing and adding the donut at some later point when I have the means in hand to do it right.
Now I have just one more question for you, Scott: Do I understand correctly that you're using only a single run per channel of the 24/30 AWG magnet wire? (I'll be using an ASL SET/SEP for these, BTW).
Thank you again and all the best,
Don
You're welcome Don, glad to help if I can. You sound to me as if you're on the right lines re room-gain and baffle-step issues. In this respect, I think it will be a suck-it-and-see situation, so trying, then deciding on baffle-size (if you bother at all) upon investigation looks like being the best way forward to me. Quite right -I use a single run of 30AWG at the moment to each drive-unit (well, one piece of + and one for - obviously!), as I usually listen to solid-state amps. Though I have a PP valve amp, I find that I rarely get chance to use it, because I'm frequently listening to quite a few different cabinets and drivers, some of which are not overly efficient, but the higher damping factor of SS amplification tends to require more series resistance to prop the bass up. You could get the same effect by using a heavier gauge wire and placing a resistor of varying value in series with the driver if you like.
As you're running SET amps, you probably won't need to go to quite the ultimate 30AWG extremes -a single run of 24AWG, either magnet wire, or a twisted pair, extracted from inside a run of Cat5 or some such will probably be sufficient. That would be my initial choice anyway. However, both of these options are very cheap, so you'll have plenty of room for experimentation without breaking the bank, going both ways.
Best & good luck with the project, and for the coming year. Let us know how you get on, or if there's anything we can help with
Scott
As you're running SET amps, you probably won't need to go to quite the ultimate 30AWG extremes -a single run of 24AWG, either magnet wire, or a twisted pair, extracted from inside a run of Cat5 or some such will probably be sufficient. That would be my initial choice anyway. However, both of these options are very cheap, so you'll have plenty of room for experimentation without breaking the bank, going both ways.
Best & good luck with the project, and for the coming year. Let us know how you get on, or if there's anything we can help with
Scott
Scottmoose said:
(Yes, excuse me, I meant to say terminal, not channel.)
I'm so accustomed to the garden-hose sized speaker cables that grace my livingroom landscape, the thought of these wispy little filaments tethering the massive BIBs to their amp was taking a while to click, and I sort of had to verify it with you even though I was sure that that had to be what you meant.
Thinking about it today brought up a related question I'd almost forgotten I had about speaker wire. I'll go ahead and raise it even though it follows the 'just one more' question I asked last time:
Is there perhaps a school of thought that favors lighter-gauge speaker wire generally over the 'garden' variety (independantly of the application we've got going here with the BIBs)? I thought I remembered reading something to that effect two or three years ago, perhaps at the single driver website (and for that matter perhaps specifically in connection with full range, high-efficiency drivers and speaker systems, which is what I was researching at the time), and more recently I thought I noticed some people recommending untwisted strands of CAT5 here on the DIY forum in applications that didn't seem especially in need of the resistance (though I could be wrong on that, of course). IOW if you feel like saying anything about the general qualities of light gauge magnet or CAT5 wire as a speaker cable in your experience, I'd love to hear.
And I really don't expect there to be another just one more..but who does? ;-)
Regards,
Don
I'm probably not the best person to ask this, as I try to stay out of the voodoo associated with cables, 99.99% of which is sheer nonsense in my view. Now, I always qualify any remarks I make on cables with the statement that this is my view, albeit one shared with plenty of other people, and under no circumstances do I suggest that anyone else has to agree with me.
Right. Thin wires. There is indeed a school of thought that suggests that all speaker cables should be as thin as possible, whatever the circumstances. This is as big a fallacy as the complete and total drivel propounded on topics like 'dielectric absorption', 'strand jumping', 'burn-in' and innumerable other matters (none of which have the slightest effect at audio frequencies or audio lengths of cable, and several of which do not exist, period). It has some technical basis, but it's frequently taken completely out of context, or simply incorrectly applied. As with everything in this life, it depends on the application.
With full-range units, the majority of which are high-efficiency types with very powerful motors and light cones, a high-damping factor amplifier (i.e. solid-state as a rule) will over-damp the driver, and bass will slump as a result. For more on this, have a look at Nelson Pass' First Watt article on current-source amplifiers and full-range drivers. Adding series resistance, either by placing a resistor in series with the amplifier and driver, or simply by using a high-resistance wire (i.e. a thin wire most of the time) between them will artificially raise the Qes of the driver (and also incidentally lower the Qms -a trade-off), and prop the bass up, bringing it into line with the rest of the frequency range. Valve amps, especially SETs on the other hand, have a much lower damping factor, and tend not to need as much, if any, resistance between them and the driver, because they are not over-damping the driver in the first place. On the other hand, as they do not put out much power, and you'll never need much anyway in a high-efficiency system to go very loud indeed, you don't particularly need a thick, low resistance, high-power-handling cable anyway.
In a lower efficiency system, a multi-way or perhaps a full-range unit with heavy, passive BSC applied, you have to be a little more careful about using very thin wires however. They need more current and power than a thin wire can deliver, either properly or safely; the thought of a length of 24AWG lying on your carpet whilst glowing red hot as it attempts to deliver high currents... you get the picture. A thinner than average wire can certainly deliver a touch of the benefits they bring to high-efficiency systems, allowing better bass performance (so many commercial speakers have a very bright balance nowadays, and this can help mitigate it, at least to a degree in my own experience) so long as you don't go too far -20AWG is about the limit I would suggest. None of this, of course, has anything to do with the black-magic waffle perpetrated by the cable industry: it's just the most basic electrical principles imaginable.
To give a commercial example: the Audience Au24. Very thin for a commercial wire indeed. I remember a nominally blind multi-wire test where all cables were used in two systems: a high-power one, and a high efficiency one, both of which played at the same sound pressure levels. In both tests, the bass on the Au24 was praised, but in the first, high-power, low efficiency system, there were also comments about it sounding 'muddled', 'confused', 'lacking in detail' etc. Now, I don't know what any of these comments really mean, and I'm pretty sure the reviewers in question don't either, but I can certainly explain why the Au24 didn't work overly well in the first system, and so can you: being a very thin gauge wire, it simply couldn't deliver the power and current it was being asked to, and the fact that this affected the sound-quality in some way is hardly surprising. In the second, high efficiency system, all such comments vanished. I note that several reviewers who use big horn systems use this cable, and love it to bits.
That is not an advert for the Au24 however, just an example. You asked about Cat5, and its popularity. I used the Au24 as an example, because it reminds me of Cat5 or magnet wire in many respects because of the basic electrical properties it shares with these wires.
Cat5. My view is that it's versatile, looks OK, and is also very cheap. You can do quite a bit with Cat5. You can extract a single twisted pair from it, or use one whole run, or two, or six (!). It has other advantages too. The fact that it is twisted together helps it to reject RFI. However, by introducing twisting, we're also moving away from the purely resistive properties we've been discussing, and moving on to capacitance and inductance, a whole new minefield. However, again this tends to be of less importance for the high-efficiency brigade than for high-power applications. So long as both are kept to a reasonable level, it shouldn't matter a whole lot for us. (It shouldn't matter that much much anyway, but there are those who persist in stating that one or the other of these factors is the devil's work, and desperately work to lower it at the expense of raising the other. Fair enough. I'll let them get on with it whilst I sip a glass of port and get on with enjoying the music, whether it be a touch of June Tabour's acoustic folk, or a full-on blast of P.J. Harvey).
Also, because each wire is individually jacketed in a nice plastic sheath means it's a little more flexible than the ceramic-coated magnet wire, whose coating can crack if you don't watch what you're doing. Twisting this stuff together is not a good move unless you want a short-circuit. Untwisted Cat5? 'haven't seen that, but then, I haven't been looking. Fair enough I suppose. I don't think it'd make much difference though, at least not in high-efficiency applications. There will be a different measured performance between a twisted and untwisted pair -whether that would be audible? I don't know, I haven't tried it, but you could always try extracting two pairs, leave one twisted and untwist the other and see if it makes a difference. I doubt it though, again, in this sort of application at any rate.
So, general conclusions. Well, for horns, like the BIB box (which is what it really is), without a correction circuit and a high-efficiency driver, very thin-gauge wire is a useful little trick to pull, especially if you're running solid-state amplification. It is not such a good idea in multi-way speakers which need more current, or high-efficiency drivers with a passive BSC circuit, which tends to lower efficiency somewhat. You can realise some of the benefits with these other types by using a thinner than average wire, but not quite so thin. 20AWG would be about the limit in my view. Tube amps, especially SETs powering high-efficiency drivers, do not need as much as they have a much lower damping factor, so you can use a slightly thicker wire if you wish. Experiment if you wish however -Cat5 and magnet wire are cheap!
Cheers
Scott
Right. Thin wires. There is indeed a school of thought that suggests that all speaker cables should be as thin as possible, whatever the circumstances. This is as big a fallacy as the complete and total drivel propounded on topics like 'dielectric absorption', 'strand jumping', 'burn-in' and innumerable other matters (none of which have the slightest effect at audio frequencies or audio lengths of cable, and several of which do not exist, period). It has some technical basis, but it's frequently taken completely out of context, or simply incorrectly applied. As with everything in this life, it depends on the application.
With full-range units, the majority of which are high-efficiency types with very powerful motors and light cones, a high-damping factor amplifier (i.e. solid-state as a rule) will over-damp the driver, and bass will slump as a result. For more on this, have a look at Nelson Pass' First Watt article on current-source amplifiers and full-range drivers. Adding series resistance, either by placing a resistor in series with the amplifier and driver, or simply by using a high-resistance wire (i.e. a thin wire most of the time) between them will artificially raise the Qes of the driver (and also incidentally lower the Qms -a trade-off), and prop the bass up, bringing it into line with the rest of the frequency range. Valve amps, especially SETs on the other hand, have a much lower damping factor, and tend not to need as much, if any, resistance between them and the driver, because they are not over-damping the driver in the first place. On the other hand, as they do not put out much power, and you'll never need much anyway in a high-efficiency system to go very loud indeed, you don't particularly need a thick, low resistance, high-power-handling cable anyway.
In a lower efficiency system, a multi-way or perhaps a full-range unit with heavy, passive BSC applied, you have to be a little more careful about using very thin wires however. They need more current and power than a thin wire can deliver, either properly or safely; the thought of a length of 24AWG lying on your carpet whilst glowing red hot as it attempts to deliver high currents... you get the picture. A thinner than average wire can certainly deliver a touch of the benefits they bring to high-efficiency systems, allowing better bass performance (so many commercial speakers have a very bright balance nowadays, and this can help mitigate it, at least to a degree in my own experience) so long as you don't go too far -20AWG is about the limit I would suggest. None of this, of course, has anything to do with the black-magic waffle perpetrated by the cable industry: it's just the most basic electrical principles imaginable.
To give a commercial example: the Audience Au24. Very thin for a commercial wire indeed. I remember a nominally blind multi-wire test where all cables were used in two systems: a high-power one, and a high efficiency one, both of which played at the same sound pressure levels. In both tests, the bass on the Au24 was praised, but in the first, high-power, low efficiency system, there were also comments about it sounding 'muddled', 'confused', 'lacking in detail' etc. Now, I don't know what any of these comments really mean, and I'm pretty sure the reviewers in question don't either, but I can certainly explain why the Au24 didn't work overly well in the first system, and so can you: being a very thin gauge wire, it simply couldn't deliver the power and current it was being asked to, and the fact that this affected the sound-quality in some way is hardly surprising. In the second, high efficiency system, all such comments vanished. I note that several reviewers who use big horn systems use this cable, and love it to bits.
That is not an advert for the Au24 however, just an example. You asked about Cat5, and its popularity. I used the Au24 as an example, because it reminds me of Cat5 or magnet wire in many respects because of the basic electrical properties it shares with these wires.
Cat5. My view is that it's versatile, looks OK, and is also very cheap. You can do quite a bit with Cat5. You can extract a single twisted pair from it, or use one whole run, or two, or six (!). It has other advantages too. The fact that it is twisted together helps it to reject RFI. However, by introducing twisting, we're also moving away from the purely resistive properties we've been discussing, and moving on to capacitance and inductance, a whole new minefield. However, again this tends to be of less importance for the high-efficiency brigade than for high-power applications. So long as both are kept to a reasonable level, it shouldn't matter a whole lot for us. (It shouldn't matter that much much anyway, but there are those who persist in stating that one or the other of these factors is the devil's work, and desperately work to lower it at the expense of raising the other. Fair enough. I'll let them get on with it whilst I sip a glass of port and get on with enjoying the music, whether it be a touch of June Tabour's acoustic folk, or a full-on blast of P.J. Harvey).
Also, because each wire is individually jacketed in a nice plastic sheath means it's a little more flexible than the ceramic-coated magnet wire, whose coating can crack if you don't watch what you're doing. Twisting this stuff together is not a good move unless you want a short-circuit. Untwisted Cat5? 'haven't seen that, but then, I haven't been looking. Fair enough I suppose. I don't think it'd make much difference though, at least not in high-efficiency applications. There will be a different measured performance between a twisted and untwisted pair -whether that would be audible? I don't know, I haven't tried it, but you could always try extracting two pairs, leave one twisted and untwist the other and see if it makes a difference. I doubt it though, again, in this sort of application at any rate.
So, general conclusions. Well, for horns, like the BIB box (which is what it really is), without a correction circuit and a high-efficiency driver, very thin-gauge wire is a useful little trick to pull, especially if you're running solid-state amplification. It is not such a good idea in multi-way speakers which need more current, or high-efficiency drivers with a passive BSC circuit, which tends to lower efficiency somewhat. You can realise some of the benefits with these other types by using a thinner than average wire, but not quite so thin. 20AWG would be about the limit in my view. Tube amps, especially SETs powering high-efficiency drivers, do not need as much as they have a much lower damping factor, so you can use a slightly thicker wire if you wish. Experiment if you wish however -Cat5 and magnet wire are cheap!
Cheers
Scott
Thanks Scott for your measurement ideas for a modified BIB. I think i will try plopping my 168S into my current pipes so i have an excuse to build another powered sub.
This way i will have another future project in the back of my mind for the 168S... I've already build a small 11L ported box, 24L box, 48L box and a Bk161 for them. They are a great value driver for someone looking to experiment with different types of cabinet designs.
Pipe and BIB are next. So far the 48L box sounded best to me... fullest, bounciest and overall the most fun to listen to.
Peace,
Godzilla
http://melhuish.org/audio/DIYBX19.html
http://www.zillaspeak.com/zillaspeakfostex24L168.asp
This way i will have another future project in the back of my mind for the 168S... I've already build a small 11L ported box, 24L box, 48L box and a Bk161 for them. They are a great value driver for someone looking to experiment with different types of cabinet designs.
Pipe and BIB are next. So far the 48L box sounded best to me... fullest, bounciest and overall the most fun to listen to.
Peace,
Godzilla
http://melhuish.org/audio/DIYBX19.html
http://www.zillaspeak.com/zillaspeakfostex24L168.asp
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