Hello All, been busy with the kids over March Break but managed to finish Bibs and have been listening-tweaking since...
Pretty nifty little speaker...
Will post some pics now and listening impressions later.
One done...
2nd cab coming together... need more clamps.. (should be my mantra that...)
Tried Gorilla glue, not crazy with the way it lay up. Was much happier with some Pl Premium industrial adhesive.
More gluing and clamping...
Sorry for the fuzzy pics... phone camera isn't great.
A quick coat of polyureathane and a coat of acrylic floor wax on the inside.
http://imageshack.us/a/img585/2273/cab4k.jpg
Temporary bracing consisting of dowels and a car jack. Panels had warped in my basement most likely due to the fact that I heat with wood and the panels had the time to dry out a bit. I'm still amazed how difficult it is to construct a square box even when all you pieces are square. It's all in the details.
Boxes boxes and more boxes.. some even make music... or will
(Living room a mess of boxes as my parents had shipped some things from France)
Up and running....
Slightly toed in...
and badly backlit.
Wrote up my impressions which I have saved on another computer... will post later.
Thank you to all who helped from near or afar... they still need some sorting out but I'm on the path to greatness..
-andré-
Pretty nifty little speaker...
Will post some pics now and listening impressions later.
One done...
An externally hosted image should be here but it was not working when we last tested it.
2nd cab coming together... need more clamps.. (should be my mantra that...)
Tried Gorilla glue, not crazy with the way it lay up. Was much happier with some Pl Premium industrial adhesive.
An externally hosted image should be here but it was not working when we last tested it.
More gluing and clamping...
Sorry for the fuzzy pics... phone camera isn't great.
An externally hosted image should be here but it was not working when we last tested it.
A quick coat of polyureathane and a coat of acrylic floor wax on the inside.
http://imageshack.us/a/img585/2273/cab4k.jpg
Temporary bracing consisting of dowels and a car jack. Panels had warped in my basement most likely due to the fact that I heat with wood and the panels had the time to dry out a bit. I'm still amazed how difficult it is to construct a square box even when all you pieces are square. It's all in the details.
An externally hosted image should be here but it was not working when we last tested it.
Boxes boxes and more boxes.. some even make music...
or will (Living room a mess of boxes as my parents had shipped some things from France)
An externally hosted image should be here but it was not working when we last tested it.
Up and running....
Slightly toed in...
and badly backlit.
An externally hosted image should be here but it was not working when we last tested it.
Wrote up my impressions which I have saved on another computer... will post later.
Thank you to all who helped from near or afar... they still need some sorting out but I'm on the path to greatness..
-andré-
Vb is volume, if I am preserving volume (via CSA) but changing aspect ratio to make flat, how do you calculate that effect? Intuitively, I know that making something 2 mm deep but wide as a wall and preserving CSA won't sound good. Is the ideal ratio the golden ratio of 1:1.6? Seems like 3-dim effects are in play and 1-dim models don't work so well at these extremes.
I'm math challenged, so skip over any higher math, but studying up on duct design acoustic efficiency, noise considerations will have it; I just use the old ~1:9 aspect ratio rule-of-thumb limit and know from experience that the Altec A8's 1:12 ratio vent is audibly resistive Vs round or square.
For compression horns, 'sound is round' and the pioneers of audio found that a ~1:1.2732 ratio was a practical limit for preserving it 'close enough' when converting their early round 'full-range' horns to rectangular as well as for blending two way horn systems when the [mid] tweeter horn is round.
GM
For compression horns, 'sound is round' and the pioneers of audio found that a ~1:1.2732 ratio was a practical limit for preserving it 'close enough' when converting their early round 'full-range' horns to rectangular as well as for blending two way horn systems when the [mid] tweeter horn is round.
GM
The 1:9 ratio to stay below is a good rule of thumb. My FIB was 3 in deep x 18 in wide so only a 1:6 ratio - should be OK then? The resistive nature of high aspect ratio channels makes sense - hence the port in Onkens behave differently than regular round or square ports. Good to know of the 'sound is round' mantra and 1:1.27 ratio - I will keep that in mind when making the next horn.
Like walking in the fall and hearing the crunchy leaves for the first time...
The speakers have been up and running for five days.
Been to busy playing music to write.
Intial impressions: I thought they imaged quite well, bass was a bit thin, and were very articulate.
Presently hooked up to a Cambridge Azur a540 amp through a single strand of cat5 cable.
My Fostex FE206's had about 300 hours of radio played though a surround sound amp on 7ch stereo, quite loud but they weren't being driven as if they were in a stand alone stereo setup.
At first, I had to turn the bass up a fair bit on the amp but now seem to be loosening up. On some recordings I find that I'm happy to run it in direct mode and no additional eq is needed. I find that it's very recording dependent right now.
Have adjusted the damping a bit. Have two layers of felt behind the speaker, fiber fill in the closed end, some 3-8th inch carpet underlay at the bottom, pennants in the openings and 5 generous handfuls of stuffing chucked down the throat.
Some of the Fostex honk and beaminess is present but it really depends on the recording on how much it is noticed.
Even with the faults, the music is very involving... got suckered in three nights out of five to late night listening sessions until waaayyyy past my bedtime.
Other impressions:
Considerably more dynamic than my open baffles... bass can be felt and not only heard. (However, I can't help but think-feel that they are giving up something though, there's something about how a large cone moves air (Audio Nirvana 15in fib anyone?))
Better at a wider range of music... My open baffles were great at jazz, quartets and small ensembles they would get a bit confused when the music was more complex.
In the open baffle's defence I don't think my Cambridge was stout enough to really make them shine; they need something with a little more authority.
The 8in Fostex units convey so much more information (hearing things and textures mostly low level I have never heard before) Also some of the subtle flanging effects that previously were glossed over are now are now part of the soundscape. How much this is due to the fact that I'm comparing full-rangers to a cross-overed speaker and that the cabinets are completely enabled on the inside is a matter of *pure* conjecture. (Sorry I did not have the patience to build two exact pairs to be able to compare the two) I do know that they are leagues ahead of the frugalhorns I built.(not enabled (speaker or cabinet)) Part of that I think is that these speakers can go much lower than the former and aren't straining to do so. (There's only so much a 4in driver can do)
The open baffles do feel a bit warmer when driven by the same amp and have a sense of space that the bibs do not.
The soundstage on the bibs although incredibly wide, on some recordings, if I close my eyes it feels like 160 or so degrees but it is pressed up against the back wall. The open baffles had a friendlier more immeadiate presence to them but did not communicate the low-level information like these do. Maybe a tweeter mounted on the back might help add space, sparkle and air.
On a more analytical train of thought. I ran some test tones.
I can barely hear 20hz and 25hz, 30hz comes on strong and then builds up from there.
Somewhere North of 12.5hz and 16hz I can no longer hear anything however I don't know if those are my 41 year old ears that played with two strokes too much in my youth or the Fostex's giving up the fight. I suspect a bit of both.
Next step: wrap the magnet and basket arms in felt, play with some plumbers putty... listen some more. After that maybe remove a bit of stuffing in the closed end, hoping that will give the soundstage some depth. There's also something a bit funny with the vocals that I can't put my finger on. (It could be the beaming and honking that's colouring them but not sure yet.) Then it will be on to the dustcapomecty and phase plug, modge podge and enable speaker, then will enable baffle using the template I made for the interior of the speaker and will use plastic wood this time instead of plaster and perhaps play with wings to widen baffle.
An album that simply sounds simply *fabulous* on these... Remnin Park by the Cowboy Junkies...
Next next step... Build an amp that will make these really sing... Fence sitting at this point... I know that I'd be bucking the accepted wisdom but a First Watt F5 tickles my fancy. We'll see...
Presently listening to the soundtrack of The Last Temptation of Christ by Peter Gabriel and have a silly grin on my face.
Thanks again to all who gave advice, commented and helped make these a reality.
-andré-
The speakers have been up and running for five days.
Been to busy playing music to write.
Intial impressions: I thought they imaged quite well, bass was a bit thin, and were very articulate.
Presently hooked up to a Cambridge Azur a540 amp through a single strand of cat5 cable.
My Fostex FE206's had about 300 hours of radio played though a surround sound amp on 7ch stereo, quite loud but they weren't being driven as if they were in a stand alone stereo setup.
At first, I had to turn the bass up a fair bit on the amp but now seem to be loosening up. On some recordings I find that I'm happy to run it in direct mode and no additional eq is needed. I find that it's very recording dependent right now.
Have adjusted the damping a bit. Have two layers of felt behind the speaker, fiber fill in the closed end, some 3-8th inch carpet underlay at the bottom, pennants in the openings and 5 generous handfuls of stuffing chucked down the throat.
Some of the Fostex honk and beaminess is present but it really depends on the recording on how much it is noticed.
Even with the faults, the music is very involving... got suckered in three nights out of five to late night listening sessions until waaayyyy past my bedtime.
Other impressions:
Considerably more dynamic than my open baffles... bass can be felt and not only heard. (However, I can't help but think-feel that they are giving up something though, there's something about how a large cone moves air (Audio Nirvana 15in fib anyone?))
Better at a wider range of music... My open baffles were great at jazz, quartets and small ensembles they would get a bit confused when the music was more complex.
In the open baffle's defence I don't think my Cambridge was stout enough to really make them shine; they need something with a little more authority.
The 8in Fostex units convey so much more information (hearing things and textures mostly low level I have never heard before) Also some of the subtle flanging effects that previously were glossed over are now are now part of the soundscape. How much this is due to the fact that I'm comparing full-rangers to a cross-overed speaker and that the cabinets are completely enabled on the inside is a matter of *pure* conjecture. (Sorry I did not have the patience to build two exact pairs to be able to compare the two) I do know that they are leagues ahead of the frugalhorns I built.(not enabled (speaker or cabinet)) Part of that I think is that these speakers can go much lower than the former and aren't straining to do so. (There's only so much a 4in driver can do)
The open baffles do feel a bit warmer when driven by the same amp and have a sense of space that the bibs do not.
The soundstage on the bibs although incredibly wide, on some recordings, if I close my eyes it feels like 160 or so degrees but it is pressed up against the back wall. The open baffles had a friendlier more immeadiate presence to them but did not communicate the low-level information like these do. Maybe a tweeter mounted on the back might help add space, sparkle and air.
On a more analytical train of thought. I ran some test tones.
I can barely hear 20hz and 25hz, 30hz comes on strong and then builds up from there.
Somewhere North of 12.5hz and 16hz I can no longer hear anything however I don't know if those are my 41 year old ears that played with two strokes too much in my youth or the Fostex's giving up the fight. I suspect a bit of both.
Next step: wrap the magnet and basket arms in felt, play with some plumbers putty... listen some more. After that maybe remove a bit of stuffing in the closed end, hoping that will give the soundstage some depth. There's also something a bit funny with the vocals that I can't put my finger on. (It could be the beaming and honking that's colouring them but not sure yet.) Then it will be on to the dustcapomecty and phase plug, modge podge and enable speaker, then will enable baffle using the template I made for the interior of the speaker and will use plastic wood this time instead of plaster and perhaps play with wings to widen baffle.
An album that simply sounds simply *fabulous* on these... Remnin Park by the Cowboy Junkies...
Next next step... Build an amp that will make these really sing... Fence sitting at this point... I know that I'd be bucking the accepted wisdom but a First Watt F5 tickles my fancy. We'll see...
Presently listening to the soundtrack of The Last Temptation of Christ by Peter Gabriel and have a silly grin on my face.
Thanks again to all who gave advice, commented and helped make these a reality.
-andré-
G'day andré,
Well done on the BIB's!
EnABL on the baffle, all outside edges and a pattern run vertically down the middle of each side and back panel will lift the sound off the back wall. You will also experience the cabinets becoming close to being sonically invisible. EnABLing the drivers completes the disappearing act.
I also recommend making some ground control pig tails. See here http://www.diyaudio.com/forums/parts/102180-groundside-electrons.html
This will take some edginess out of the drivers and will reveal even more detail than you have already.
Cheers,
Alex
Well done on the BIB's!
EnABL on the baffle, all outside edges and a pattern run vertically down the middle of each side and back panel will lift the sound off the back wall. You will also experience the cabinets becoming close to being sonically invisible. EnABLing the drivers completes the disappearing act.
I also recommend making some ground control pig tails. See here http://www.diyaudio.com/forums/parts/102180-groundside-electrons.html
This will take some edginess out of the drivers and will reveal even more detail than you have already.
Cheers,
Alex
Hi Alex, thanks for the input.
I'm enjoying the speakers immensely... Listened to some John Lee Hooker last night that
was ear candy.
Do I do the contour of the side and back panels as well or only the center-stripe?
Do I make the pattern the same size as I used on the inside?
Thank you,
-andré-
I'm enjoying the speakers immensely... Listened to some John Lee Hooker last night that
was ear candy.
Do I do the contour of the side and back panels as well or only the center-stripe?
Do I make the pattern the same size as I used on the inside?
Thank you,
-andré-
G'day andré,
Great to see you're enjoying them!
The hard work you did with EnABL on the inside has laid a foundation that will come to fruition as you do the external EnABL.
You could use the same block size for the outside of the enclosure. Or if you are obsessive like me you would calculate block size based on four times baffle width.
Aesthetics do become important with the baffle. Start by drawing up a template on a piece of paper and centre the pattern along the top of the baffle. Then run the pattern down each side and again centre the pattern on the bottom edge of the baffle.
Centre the pattern for the top of the side panels as well. When doing the vertical edges of the side panels, offset the patterns so that it looks like the baffle pattern wraps around to the side. Do make sure that you keep the pattern one block width from the edge of the panels. Do the same for the back panel. Then run a vertical pattern down the middle of the side panels and the back. Finally, run a pattern along the edge of the wood on the top of the mouth. There is more but we'll get to that later.
This is a lot of work, so do some on one speaker only, then stop and listen to the changes. Usually it will sound strangely unbalanced. Then when you do the same to the other speaker things will snap back together, but with a greater clarity and naturalness. You'll see what I mean when you do this.
Hope that makes sense.
Cheers,
Alex
Great to see you're enjoying them!
The hard work you did with EnABL on the inside has laid a foundation that will come to fruition as you do the external EnABL.
You could use the same block size for the outside of the enclosure. Or if you are obsessive like me you would calculate block size based on four times baffle width.
Aesthetics do become important with the baffle. Start by drawing up a template on a piece of paper and centre the pattern along the top of the baffle. Then run the pattern down each side and again centre the pattern on the bottom edge of the baffle.
Centre the pattern for the top of the side panels as well. When doing the vertical edges of the side panels, offset the patterns so that it looks like the baffle pattern wraps around to the side. Do make sure that you keep the pattern one block width from the edge of the panels. Do the same for the back panel. Then run a vertical pattern down the middle of the side panels and the back. Finally, run a pattern along the edge of the wood on the top of the mouth. There is more but we'll get to that later.
This is a lot of work, so do some on one speaker only, then stop and listen to the changes. Usually it will sound strangely unbalanced. Then when you do the same to the other speaker things will snap back together, but with a greater clarity and naturalness. You'll see what I mean when you do this.
Hope that makes sense.
Cheers,
Alex
Buy a Panasonic wm61a mic capsule from Digikey ($2 ea). Look up circuit schematic on web for wm61a and measurement - wire 3.5 mm plug from cheap old set of headphones to mic. Plug into mic input of pc and use Holmimpulse software and you are in business. Panasonic mic is being discontinued and replaced by another brand - wm61a has calibrated file for Holmimpulse, but is basically flat response from 20 Hz to 20 kHz.
The FIB took a lot of messing around with the stuffing. It took me at least 7 iterations to get it right. It helps to have measurement to see where problem is and to balance left and right.
Glad you are happy with plan and found it fun.
Update-
It's back to the drawing board on the FIB for me. I underestimated the importance of solid bracing. My poorly built FIB "rattled and hummed" when pressed. No fault of the design, just another lesson I needed to learn. I will need to rebuild it with the recommended bracing scheme that you clearly stated. At least I didn't have a lot of time and money tied up in the first model
It usually takes me at least two or three tries to succeed at most things diy.Thanks for pointing me in a direction for measurement. I've been researching my options for the last few days. As I am mac based I will start with REW 5. I don't know how or if it compares to Holmimpulse but is compatible with my computer. It looks like I can use the mic output from my RS 33-2055 meter. I may pick up an inexpensive pc for Holmimpulse someday but not possible now. Too many projects, too little time (and $)... Anyway, thanks for the leg up.
Have you run these through the BIB calculator spreadsheet? The CSS FR125SR ends up with a 48 in tall cabinet x 7.38 in wide x 9.38 in deep cabinet, driver 21 in from top. You could flatten this and make a FIB as the requirement is a 84 square in cross section. If you made it 5 in deep the cab would be 16.75 in wide and you could wall mount it for a nice out of the way back channel.
The TB W3 is much smaller: only 32 in high x 5.38 in wide x 7.38 in deep, driver 14 in from top. Again, this could be made into a FIB with a 10 in wide cabinet x 4 in deep.
For a rear channel, I think the TB W3 is fine as it keeps it smaller and you don't need the bass as that is from a HT sub.
I did run them in the calculator, Infact the CSS driver was already in the one I had.
As I have not used the calculator much I wasn't sure which figure gave me the distance the driver had to be away.
Flattening them out is an awesome idea, I want to get the driver 100mm off the ground to be at ear level when listening.
Downside is looking at the price of foam board, I think making them in 12mm or 16mm will be a heap more cost effective.
What the trick in the caculations withunfolding the design?
Obviously you need to keep the line length the same, but I gather there is some length hidden in the fold?
As I have not used the calculator much I wasn't sure which figure gave me the distance the driver had to be away.
Flattening them out is an awesome idea, I want to get the driver 100mm off the ground to be at ear level when listening.
Downside is looking at the price of foam board, I think making them in 12mm or 16mm will be a heap more cost effective.
What the trick in the caculations withunfolding the design?
Obviously you need to keep the line length the same, but I gather there is some length hidden in the fold?
You want the driver 100 mm or 4 in off the ground? You mean 100 cm? No need to unfold if 100 cm, move the FIB up or down until driver (Zd) is at height you want. Unfolding is not tricky, just double the length but you are building a triangular shaped box now. Unfolded may be a problem as mouth may bump into ceiling if driver is at ear height. In Australia foam core is expensive I hear so plywood may be better. Just not as easy to work with...
You are trying to preserve the cross sectional area as the sound makes the U-turn. The easy way to look at it is that the edge of the diagonal divider is equidistant from the two walls and the bottom. If you go straight and do not have a bend, then the cross sectional area simply continues to expand. Technically, if you want to recreate the geometry of the U-turn in a straight, it is an expansion (first corner), followed by a contraction, followed by another expansion (second corner). You want to keep the bend as the mouth will end up near the ceiling - which could be good as you get more bass from ceiling and wall loading.
What to do with a fat, squatty BIB.
Liked the looks of a Visaton BG 17-8, and wanted to put them in a BIB for my garage. However, after plugging in the parameters, I realized that the cabinet was going to be rather short and tubby:
Internal Measurements
29" X 13" X 19"
A-B-C = 9.5"
When sketching the cabinet up, I realized that mounting the speaker on the side with two slanted baffles, makes more sense.
The "Zdriver" length is supposed to be ~12.25". But, to get the driver to fit between the internal slants I had to drop the driver to 17".
Will this have a huge effect on the sound? Did I miss something in converting to a sideways design?
Liked the looks of a Visaton BG 17-8, and wanted to put them in a BIB for my garage. However, after plugging in the parameters, I realized that the cabinet was going to be rather short and tubby:
Internal Measurements
29" X 13" X 19"
A-B-C = 9.5"
When sketching the cabinet up, I realized that mounting the speaker on the side with two slanted baffles, makes more sense.
The "Zdriver" length is supposed to be ~12.25". But, to get the driver to fit between the internal slants I had to drop the driver to 17".
Will this have a huge effect on the sound? Did I miss something in converting to a sideways design?
Make the horn wider and shallower. The driver is only 2.24" deep, as a starting point double that to 4.5" internal depth, and re-size.
Be sure to keep the cross sectional area the same.
The A-B-C measurements can be adjusted accordingly.
The horn still starts from -0- csa, and expands conically to the max opening. These could be hung on the wall to put the driver at the optimal height for your listening area....horn opening up or down, loading the floor or ceiling, or even sideways to load a corner.....
John
Be sure to keep the cross sectional area the same.
The A-B-C measurements can be adjusted accordingly.
The horn still starts from -0- csa, and expands conically to the max opening. These could be hung on the wall to put the driver at the optimal height for your listening area....horn opening up or down, loading the floor or ceiling, or even sideways to load a corner.....
John