AudioNervosa
Self Medicating => General DIY => Topic started by: richidoo on September 28, 2013, 08:28:37 AM
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I ordered the Kairos kit from Meniscus. It is designed by Jeff Bagby, using the Satori drivers from SB Acoustics in Indonesia.
(http://meniscusaudio.com/images/Kairos.jpg)
Manual (http://meniscusaudio.com/images/The%20Kairos%20Monitor%20Speaker%20by%20Jeff%20Bagby.pdf)
(http://i109.photobucket.com/albums/n70/jeffbagby/SB%20Kairos/102_1991.jpg)
I ordered the bare bones kit, with no parts upgrades. I wasn't excited about the upgrade caps they offered, nor the litz coils, nor the binding posts, nor the paper reflex port. When I saw the invoice with itemized parts I was a bit surprised to see that the stock parts include an iron core woofer inductor. But it was shipped within 3 hours of my ordering and Mark at Meniscus is a pleasure to work with. The kit price is very reasonable for just the drivers alone.
More to come.
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I ordered the Kairos kit from Meniscus. It is designed by Jeff Bagby, using the Satori drivers from SB Acoustics in Indonesia.
(http://meniscusaudio.com/images/Kairos.jpg)
Manual (http://meniscusaudio.com/images/The%20Kairos%20Monitor%20Speaker%20by%20Jeff%20Bagby.pdf)
(http://i109.photobucket.com/albums/n70/jeffbagby/SB%20Kairos/102_1991.jpg)
I ordered the bare bones kit, with no parts upgrades. I wasn't excited about the upgrade caps they offered, nor the litz coils, nor the binding posts, nor the paper reflex port. When I saw the invoice with itemized parts I was a bit surprised to see that the stock parts include an iron core woofer inductor. But it was shipped within 3 hours of my ordering and Mark at Meniscus is a pleasure to work with. The kit price is very reasonable for just the drivers alone.
More to come.
Let me know what you think of the SB woofer.
It looks like a copy of the Vifa unit.
I was interested in the SB23NRXS45-8, 8" Woofer
but its a few db's short of what I want.
Greg
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I have the regular SB29 tweeter that tweeter is an upgraded unit. Let us know how it sounds.
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Yeah, they are both hotrod drivers designed by this Ulrich guy who designed for Scan Speak, iirc. Wilson uses this woofer for their midranges. The standard tweeter is very good one, used in the Janzen electrostat panels... but this one has some major tweaks to the base model.
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Is it soup yet ?
charles
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Hi Charlie!
The boxes are almost finished. I need to cut the driver holes, install the bracing and stuffing, build the crossovers. I am ordering hot rod coils and caps on Monday. I bought some nice stain and varnish today. Probably another week or two until ignition. I am anxious to hear them! Thanks for axing!
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Yay, so glad to see you doing this project. 8)
Looking forward to hearing your impressions.
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Got em runnin tonight. YAY! They sound BIG and very nice. Amazing low end for 6", very dynamic, revealing, natural honest tone.
We listened to Brendel's Moonlight Sonata, the 1st two movements were awesome, I was anticipating even more on the loud and fast final movement, but turns out that movement is compressed and lowered volume compared to the other 2 tracks, so the vavavoom was not as I hoped. The cool thing was that I never noticed the compression or the level reduction with previous speakers. They are so dynamic music feels very alive. The tonal texture on the piano is excellent. You can choose to listen to it or ignore it, just as I was hoping. Thanks to paper cone and silk dome.
Still need to varnish and install the final binding posts. Using cheap heavy brass Dayton posts temporarily.
These are brand new, never played a note before the Beethoven, so lots more bass and clarity to come with break in. Hard to imagine there's more still in the can. Pics and adjudication to follow.
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Sounds (pardon the pun) very promising! Keep all of us updated. :thumb:
SN
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My wife says it sounds better than my previous speaker builds. Says it doesn't sound shrieky. Can play loud without hurting. Thanks, I think... :roll:
She is blasting Lady Antebellum now so that's a good sign that they sound good.
From the other side of the house they sound good, which means good freq. balance and dynamics.
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Got em runnin tonight. YAY! They sound BIG and very nice. Amazing low end for 6", very dynamic, revealing, natural honest tone.
We listened to Brendel's Moonlight Sonata, the 1st two movements were awesome, I was anticipating even more on the loud and fast final movement, but turns out that movement is compressed and lowered volume compared to the other 2 tracks, so the vavavoom was not as I hoped. The cool thing was that I never noticed the compression or the level reduction with previous speakers. They are so dynamic music feels very alive. The tonal texture on the piano is excellent. You can choose to listen to it or ignore it, just as I was hoping. Thanks to paper cone and silk dome.
Still need to varnish and install the final binding posts. Using cheap heavy brass Dayton posts temporarily.
These are brand new, never played a note before the Beethoven, so lots more bass and clarity to come with break in. Hard to imagine there's more still in the can. Pics and adjudication to follow.
They will need break in time that may be another reason for sounding compressed.
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Picture time!
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More pics
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They are sounding mighty fine. Still breaking in, but good enough now for sitting down for long listening. They are much cleaner and lower distortion than my previous speakers, so I am happy with the decision to move on to the next chapter.
Still deciding whether to add subs or not. For normal music down to 50Hz it is not needed. For symphonies, dance, organs, etc it will be needed. The huge woofer coils make excellent bass.
North Creek 10ga coils on woofers and 12ga on the tweets. Jantzen SuperiorZ caps and the resistors are the metal oxides that came with the kit. Once I decide that I am happy with the tweeter levels then I will put some Duelund graphite resistors, or make my own from pencil leads.
The woofers have incredible detail, layers and layers deep of texture. The tweeter has all the extreme detail of a metal hard tweeter without the bite, or the distraction. I haven't really done much serious listening to strong quartets or trumpets so time will tell if these really are world beaters. But so far there is no reason to think they will not be that good.
The edges are rounded over using table saw for rough cuts, block plane for shaping, sanding and a little filler. There is lots of internal bracing, mostly corner bracing between two adjacent sides which I have found to be the most efficient kind of bracing. The boxes are very quiet considering only one sheet thick. I wanted to put the roofing membrane in them but the kind I want is not available in single roll.
I think I have a little too much stuffing, I'll experiment after break in is done. I'm using Electratube binding posts. They are very nice. Pure copper, gold plated, minimal mass and no threads in the signal path, and only $60/4.
They are playing just fine on Sol's I-15 integrated amp, 15 watts. But his I-60 will be a better match. I never thought a 85dB sensitive speaker could sound so alive and musical, but it does. The simple shallow crossover filters and super high quality parts minimize the loss of life.
Still have to stain and poly them. Then g2g. :)
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Wow! Nice work, Rich. If I tried to build my own speakers they'd end up looking like some sort of Audio Picasso!
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Yes, nice work indeed. It was interesting to check out the electracable website again. I'm looking forward to the finished product
Nick
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Same here. I'm looking forward to the finished product as well. I wish I could be there to listen to them at your next g2g.
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A guy over on PE forum wisely suggested I remove the STEEL bolts from inside the air coils. DUH! :duh I ordered some nylon replacements today.
$500 for coils and I sabotage them before they even play one note. haha
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God don't make no junk...... and neither does Rich! :thumb:
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looking forward to giving them a listen...
got new parts from sonicraft... so far, albeit early in the break-in, liking the changes that the dynamicaps make on the Zephyrs... tames the compression driver in a way that I like better than all the other stuff I have here does, including all my different oil caps...
should have these to their new owner next week when he is back in town... now on to the 3Pis and the BMS4550/SEOS12/AE TD15M designs.... all the parts except some WBT Nextgen binding posts and mundorf silver/oils caps for one spot in tweeter circuit of 3Pis are here for those....I've got mundorf supreme in the right size, but not the silver oils... so much for clearing out these storage tubs full of crossover parts if I keep buying more stuff :(..... calling madisound in a minute to get the rest of that stuff here asap... keep forgetting to do it until after they close...
Red Wine Signature 57 finally got here after 5 days of shipper trying to find where they put the box... that's breaking in on the zephyrs now... got a very similar house sound to the Signature 16 I've been listening to, but definitely can tell the tube stage isn't in there....
there's gonna be enough stuff here to have a G2G of my own soon.... and I haven't even done any more measurements on the big boy horn projects.... not enough hours in the day when you have little boys that want 100% of every minute :)...
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They are starting to come alive now after about 20 hours. At first there was no center image at all. But it is starting to focus now.
I listened to my newest Julia Fischer album about 5 times yesterday, over and over. Wow, the detail on the strings is awesome. Percussion too. Basically the tweeter with this huge coil is a MONSTER. But totally inoffensive, since it is a soft dome.
Mono recordings make a center image strong enough to perceive while I am reading or typing, not even concentrating or looking at the speakers. Imaging was a disaster at first.
The woofer coils are about 200 feet of 10ga magnet wire. Remembering back to the first set of speaker wires I had, Anticable which were 8ga magnet wire, I was worried that if 8 feet of the stuff is THAT bad, then 200feet might not be so great either. But I went on faith that so many good opinions of North Creek big coils are the best available. I don't hear the copper ringing or trashing noise of the Anticable at all. But breaking in all that dielectric probably takes a little extra while than 10 feet of 18ga steel lam coil that came with the kit.
One problem that is becoming more obvious as the focus improves is that I am hearing a little bit of stuffiness in the low midrange. Some possible reasons for this:
1. Steel mounting bolts in the center of the woofer coils are adding hysteresis. Not sure if that would be audible, but the resolution of these drivers with these 10ga coils is unbelievable, so maybe. I am replacing the steel bolts and buts with nylon bolts and thread inserts. Parts ordered and on the way.
2. Binding post holes. The boxes are sealed, no ports. The posts I am using are Electratubes, which are basically just plastic bushings with conductors through them. After I do the wood finishing I will press them in to seal up the 7/16" holes. But for now I am running the wires out through the holes and clamping the bare wires in some brass posts to connect them to my bananas. On high volume tunes I can feel air through the open holes. At normal listening levels I can't feel any air motion, so I don't know if these small holes might have an audible effect. Today I will solder on the electratubes and push them into the holes just enough to plug them, not all the way in. twss
3. Too much stuffing. I am also hearing a slight softness to midrange instruments, so I think I need to pull out some stuffing. I don't think this would blur the low midrange, though. If anything, it should make them even tighter by increased damping of the driver motion.
4. The 17 liter box is supposed to be Qts ~ .7. Maybe Q is higher due to smaller box than expected or variation of driver Q. This would give a bass bump and some looseness at the bump.
5. It could be cabinet vibration. I am using all kitty corner bracing which links adjacent walls and reaches in about 3 inches to the 1/3rd width of the cabinet. The box is pretty solid to knock test. But on high volume bass heavy songs I can feel vibration on the sides. I can add a couple cross braces inside the box to link the sides together against internal pressure. This might be the most likely cause.
EDIT, or it could be that 20 hours is not enough break in time... That's my bad habit of thinking too much before break in is finished.
Any other opinions on what can cause minor low mid blur in a small bookshelf? Most audible on acoustic bass and deep male voice. Probably 60-100Hz. Thanks
Rich
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Great looking project Rich! I love the profile you put on the front baffles, very sexy. Had I seen this thread a couple weeks ago, I would have bought a router bit to mirror that exact profile for the speaker I'm building right now.
How much did the kit cost?
Bob
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Hi Bob! :D
Thanks. The roundover are a bit too big for a hand router so I did them with tablesaw, plane and sander. The top angle is 104 degrees, not 90, so router wouldn't work there anyway.
The kit cost me $832 shipped for the "basic" kit, which is only drivers and crossover components, nothing else. The full kit comes with very cheap parts to get it running, but in my opinion they are not good enough for these drivers. I probably have about $1500 in it with wood, upgrade crossover, and other parts.
In response to the roaring world economy :roll: SB Acoustics recently reduced the price of the drivers, so Meniscus has reduced the price of the kit. A basic kit is now $705 shipped. I haven't heard the kit crossover yet, but the drivers alone are worth that, imo, at least in comparison to other brand drivers playing in this league. The kit crossover parts are as cheap as it gets, but that's how the designer Jeff Bagby listens to it and he likes it.
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Thanks Rich.
Sounds one of those kits that you can "take it as-is", or is plenty ripe for adding some audiophile zazzing to, and making it your own. Since you're knocking on the door of a grand, a fellow could take that up to a couple grand pretty easily.
Sounds like a fun project (assuming you wanted to make it that), but based on how you installed the XO parts, it looks like you didn't build it for tweaking and fiddling often.
I'm curious to know if you can hear a difference with the nylon bolt as opposed to the steel. I know of one fellow that drills and glues a wooden dowel with a wooden cap ("lid") to the wooden block and captures the inductor that way, with no ferrous material involved. Just an idea.
Rock on man. Great thread. :thumb:
Bob
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Thanks Bob! It's always so much fun when you come to visit! :thumb:
Previous projects have taught me it's better to start with good parts and not have to worry about cheap parts quality being the cause of tuning issues. I guess with more experience I could use cheaper parts without problems. I could have used Duelund caps but I thought that was overkill, and I knew the Jantzens are nice and I liked how they sounded in my previous build. I may put Duelund resistors in later.
That's a good idea about wooden clamp down for the coil. I have wooden center spacers and washers drilled with 1/4" center holes. But I want to be able to remove the xo parts if I want to go active, or whatever. I am gonna replace the steel bolts with Dubro 3" nylon RC-airplane wing hold-down bolts. They are designed to break in a crash to save the wing, so they wouldn't be strong enough to ship the speakers, but good enough for general moving around. If I sell them I'll bolt down with steel for shipping.
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Thanks Bob! It's always so much fun when you come to visit! :thumb:
:rofl: I'm not "quite" sure how to take that, but since I've had a few drinks and am feeling a general sense of self awesomeness, I'll take it as a complement.
Thanks Rich. :thumb:
It sounds like you've got the inductor hold-down figured out, but since I'm a man with problem solving flowing through his veins, another idea occurred to me. Since you aren't here to stop me right now as I type this, I'll go ahead and tell ya what I've got in my noggin.
Let's just say the center hole in the inductor is 1.5" in diameter. I'd grab a 1.25" dowel rod, and use a forstner bit to recess the rod into the XO plate (put some glue in there). Then recess the rod into the "cap" that will hold the top of the inductor (don't put glue in there). Then you could drill a pilot hole through the center of the cap, and center of the dowel rod. At that point, you could use a small wood screw to hold things together. The benefit here is that with a simple small Phillips screwdriver, you could take the inductor out, but still have the 1.25" dowel rod at the center of the mass to hold things together.
But then again, I tend to over engineer things.
You could also drill some small holes in the XO plate and use cable ties and hot glue to hold the inductor firmly in place and be done with it. :duh
Ok....that's enough of that. :D
Bob
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Yes, that might work!
I think UPS could destroy it, but then they could probably destroy the steel bolt idea too if they dropped it just right.
These coils are probably 15 pounds each, 5.5" round, 2" thick. They really should be built into a separate XO box, blocked in with wood on all sides. But that would make the box too big or make the internal volume too small. Probably already eating into the designed volume too much.
Thanks Bob!
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15 pounds each!?!? :shock:
Knowing that, I'd put them squarely at the bottom of the stand, right by the floor. Use the weight to help keep it from being so top heavy.
But yea, a disgruntled underpaid guy driving around in a big dark metal box in the summertime with no air conditioning definitely has the ability to break your shit.
Bob
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Yup, when I build the tower version with subwoofers I'll put the coils in the bottom.
My UPS guy is an amateur musician, makes records people and produces songs on his computer at home. He hangs out for an extra minute when I'm outside building speakers. Not this time of year tho! Unfortunately, all UPS employees are not like that. I had a friend back in NY in 85 who worked at UPS transfer station in Manhattan. He said they time you with a stopwatch to see if you throw (yes throw) enough boxes per minute to deserve your job. As long as somebody catches it, no problem! :thumb:
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Bob like the dowel idea. May I suggest the dowel extend to top of inductor and use a wood cap to hold in place. Looking like a mushroom. May add some resonance control as well.
Hey Shane good to see you posting again. Rich making progress, learning and having fun "Priceless".
charles
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Indeed Charles, indeed. :thumb:
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Yes, that might work!
I think UPS could destroy it, but then they could probably destroy the steel bolt idea too if they dropped it just right.
These coils are probably 15 pounds each, 5.5" round, 2" thick. They really should be built into a separate XO box, blocked in with wood on all sides. But that would make the box too big or make the internal volume too small. Probably already eating into the designed volume too much.
Thanks Bob!
Bob,
I'll bet that IS eating into the designed internal volume. Having sufficient stuffing makes the box appear "larger" so tune accordingly.
Jim
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I'll bet that IS eating into the designed internal volume. Having sufficient stuffing makes the box appear "larger" so tune accordingly.
You are right Jim, the large coil is eating into the volume. But I compensated for that by omitting the reflex port on Jeff Bagby's recommendation. Due to the very low driver resonant freq. the bass FR is excellent without port, and omitting the port makes better bass transient response.
I also used a different bracing scheme which should use less volume than the original design. But there were some braces that didn't fit after crossover parts were installed, so I'll need to make some side to side cross braces. I can feel the box sides moving on low notes. I'm pretty sure that's where my low midrange problem lies.
Woofer upper range sounds a bit reticent compared to the tweeter at crossover freq, so I think I have a bit too much stuffing in there, as the stuffing only acts on the woofer, not the tweeter. Bass is well damped and very clean. By removing some stuffing I hope to free up the woofer to play high range with more detail and a touch louder to better match the tweeter, while retaining the clean bass I have now with maybe a little more loudness. A bit looser ("warmer") bass is a fair price to achieve good M/T matching. You are right that acoustic damping is a very critical factor! Too much or too little can ruin the recipe.
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I got all of the planned mods done:
Replaced Dayton brass speaker binding posts (used as wire clamps to banana plug) with pure copper Electratubes. No threads in signal path, soldered connections. The cabinet holes are sealed up now too.
Installed 5 new braces in each speaker. 3 corner braces from the sides to the baffle and 2 side to side cross braces in each cab. Max unbraced span is now <3". Knock test is pretty solid.
Replaced steel bolts, washers and nuts for holding down the coils with nylon bolts and zinc threaded inserts.
I also tightened down the tweeter screws which had come a little loose after only 50 hours of playing. That's a 1" long #8 sheet metal screws in 1.5" baltic birch! I was surprised to find them a little loose.
Overall it sounds more present, and purer treble. Imaging is much improved, but still not as expected.
Despite the new bracing there is not much change in the bass, it still sounds too thick and blurred. which is strange. So I guess it did not have anything to do with the box vibrations. Could be internal box reflections, the reflected waves pushing on the back of the cone. So maybe I need more stuffing. I read that FG stuffing is much more efficient sound absorber than dacron pillow fluff, so I'll change to FG and fill it up. I can pull some out to find the sweet spot.
That's all for now...
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Have you seen the shredded denim material that's pressed into "sheets"?
I don't know much about it, but it was recently talked about on AC in the GR Research area.
Looks like neat stuff.
Bob
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Ya I have a lot of that stuff - 12 pieces of 2'x8'x4" thick! :shock: It is great for bass traps. Bryan once said it absorbs better than OC703. I was thinking of using it but it sheds a lot of dust, so I'll need to screen it off with fabric to keep the dust out of the drivers, but FG sheds too.
I will check out the GR thread. Thanks Bob!
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You'll never find the thread, as it was buried in a thread about an up-and-coming new driver. It wasn't specifically about absorption.
>>>>> Check here (http://www.audiocircle.com/index.php?topic=120804.msg1280249#msg1280249) <<<<<
But yea, four inches thick would be hard to deal with for use lining the inside of a small speaker. The stuff in that thread is thinner than a large coin.
On a side note, it sounds like you had some serious plans if you bought that much. You could insulate the attic of a small house. haha
Hope that helps ya Rich. :thumb:
Bob
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I bought that stuff a long time ago to build an anechoic listening chamber. It's floppy so it needs a wooden shell to hold it up. Someday I'll get back to that.
I do want to stuff these speakers full as an experiment. I have the sides partially lined with dacron mat now but it's not enough. The denim fill should be enough to kill the bass freqs and tighten the bass, if the problem is caused by reflections.
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Thanks for finding that link Bob.
I have some 1" thick denim sheet, but it is too powerful for something like a full range driver. I was looking all over for 1/2" felt to line the horns of that last big speaker I built but I couldn't find any in this country. So I ended up using not very absorbent felt pad intended to be put under a big rug. Good to see it available now.
I also saw that Home Depot now sells the denim insulation in small rolls 16"x48"x2". That would be pretty handy for stuffing speakers.
http://www.homedepot.com/p/t/202710055 (http://www.homedepot.com/p/t/202710055)
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Good deal Rich, sounds like you're hooked up.
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I think the foggy bottom is caused by my recently acquired oldie Oppo CD player. I've been listening to LP, radio today and not heard it.
Listening now to 1960s Christmas carols with male baritone singers using the Sonos analog out and not hearing it.
That's my Christmas present!
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The bass problem was definitely the CD player.
I'm just using the Sonos zone player now, sans DAC, and that's better than the Oppo. What a relief!
I'll get the DAC back in a day or two, that should be another big jump.
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Ah Ha ! Could this be some proof that the arguement of speaker first as oppossed to source end first in our systems is coming through !
It appears the bass was OK but the source limited such. The Ol garbage in garbage out theory. Interesting.
charles
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Listened to these in Carlman's system today. A revelation. They really sound fantastic. Incredible coherence from 100Hz up. The ample power of the McIntosh amp really made them come alive, as did his great DAC. Sol has modded the Belles preamp and the Mac amp, making the system really improved since my last listen. The Kairos speakers sounded very refined, very detailed, and very musical, especially after we put in a -2dB shelf on the tweeter, which I will do with resistor mod. Neither of us like flat FR, although the tweeter is not objectionable even when flat.
Frustratingly the bass thickness tone did rear its head again, so maybe it is in the speakers. I'll ask Mr Bagby for some advice.
Some ideas came to mind:
Increase the Qts to dry out the bass, increase control. It is currently Q .69 sealed. That should be good enough, but maybe not for the very low bass. Lower Q will make LF even louder, so I don't know if it will help or hurt.
Try a ported box. If the large excursion while playing LF is the cause of the distortion then a ported box would limit woofer excursion at LF. But the price is group delay, I don't really like ported speakers.
Leave it as is and just high pass it high enough to avoid the problem, put a sub under it. We tried hi passing the speaker with foobar EQ. It seemed to help a lot, but even up higher with female vocal low notes there was still some feeling of it. Weird. If I can fix this these will be super awesome.
We both agreed that while they play pretty low, it would be nice to have the bottom octave for impact, and to allow overall louder SPL for rock and symphonies. Relieved of low bass they can play very loud without feeling strained.
I was looking at plate amps tonight. Ryhtmik servo system looks like a good choice, or a Digimoda 2 way computerized plate with built in DSP, but I don't really want ICE amps on the mid/highs. Any happy Rythmik users here? Sealed stereo GR 12s is what I'm thinking.
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I tried putting a small 18ga steel lam coil of same value on the woofer in place of the 10ga air core to see if that had any effect on the LF distortion, no change, other than loss of dynamics and fine detail.
I'm starting to think that it is actually the cabinet wall vibration from internal pressure. I can still feel very slight vibration on all the walls, so if I can feel it then I can hear it. They really should be totally inert at this level of performance. Cab vibe was my first suspicion, that's really what it sounds like, and there's really no other possible explanation. High detail drivers demand very quiet boxes. I had similar problems with boxes for the Feastrex drivers until I went to open baffle.
Not sure what materials to use though. Can't find or afford the phenolic materials that Wilson uses, nor could i cut it if I could get it. I need to keep the exterior baffle width at 9", but that allows sidewalls up to 2" thick if I redesign for internal volume. Maybe 1/4" steel plate laminated to wood? Panzerholz wood product is supposed to be the ideal speaker making material - extremely stiff and extremely damped. There is a dealer in NC. Or maybe LOTS and LOTS more bracing (B&W Matrix style) inside a wood box. How about 2" thick foam/wood sandwich? Or the old standby: 3 layers of MDF on the sides and 4 layers on the baffle.
Many companies build very inert bookshelf speakers. It can't be rocket science?
Lenahan uses steel plates glued into high density engineered wood material.
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Also building ported boxes to see how that sounds, it will reduce woofer excursion at LF to allow louder playing. Also trying reducing the baffle step correction to get some more headroom before bottoming. They will be happier with bass drivers.
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Since you've got 2" to work with, how about two layers of BB ply with sand in between.
like a "box in a box".
Regarding the Panzerholz, I've done extensive research to find a dealer (a couple years ago) to no avail. I even had a forum buddy ("Thunderbrick") visit some hardware stores in Germany while he was over there. In the end, I gave up. I'd greatly appreciate a link to the dealer you're referring to.
Bob
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Thanks Bob! You reminded me that I already thought about sand about 2 months ago, based on your success with it, and already designed a box like that. I think that is the best route.
These are the dealers I have found for Panzerholz. It is made in Germany by the Delignit company. You might find more sellers if you search Delignit. There's not much searcing just Panzelholz, just a bunch of high end audio links. :rofl:
http://www.ltlewis.co.uk/b15.htm (http://www.ltlewis.co.uk/b15.htm) UK
http://powerstreamindustries.com/autosport-wearply.asp (http://powerstreamindustries.com/autosport-wearply.asp) NC
http://bkbindustrial.com/ (http://bkbindustrial.com/) Canada
The NC seller tops out at 1/2" thick, but that's thick enough for how you build!
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Glad I could help Rich.
I've wondered about the sand fill thing. I was thinking about mixing in a 50:50 of sand, and some form of soft mushy bead. Like a rubber pellet type thing. In my mind, I see the dampening effects of that mixed with sand being better than just sand.
Thanks for the Panzerholz information. :thumb:
Bob
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Interesting idea about the rubber beads. I was thinking about Green Glue being a great damping material, but I don't think it could be used with sand. I did remember an old idea I had about laminating several layers of thin wood sheet together with green glue. I once did it with two pieces of 3/4" greenglued together. It worked pretty well. But more layers of thinner wood would probably work better. Lightweight layers should damp easier than heavy, but stiffness suffers with thin wood. Hence the invention of carbon fiber! No I'm not making CF speakers, at least not yet...
So how should I go about making this sand cabinet? Should I build a frame along the edges, and glue on the thin wood panels? Or just glue together the panels on edges without a frame, with one layer of continuous sand all around the speaker?
Do I need small cube wood blocking between the panels to keep them from bulging out from the sand/gravity pressure? Would those connections diminish the damping of the sand? I guess 1/4" wood is stiff enough to hold up some dry sand without flexing too much.
How do I handle the horizontal panel at the top? The sand will only damp the bottom (interior) surface. I was thinking I could slant the top panel 15 degrees to that there would only be a small undamped air bubble at the very top corner after sand settles.
Should I make all the panels open to each other so that the sand flows in from the top, or make separate sand filled panels that glue together?
Thanks for any advice, oh sand-master - or anyone else!!
Rich
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It wouldn't be too hard to built, basically each speaker would consist of building two boxes, but might be hard for me to explain....
Let's see. To keep it simple, let's say we're building a cube that consist of nice round numbers.
Build the inner box; 10"x10"x10"
Space strips of 1"x1" wood all the way around the box.
Built the outer box 12"x12"x12" (remember, it's 12" on all outside dimensions, because of the one inch thick strips on all sides).
Leave the top panel off. Fill with sand. tap with rubber mallet to help settle sand, refill as necessary. Install top.
Where the wires come through, install a 1" thick block that's 2"x2". You can then safely drill two holes from the outside all the way into the interior without drilling into the sand cavity.
Where the drivers mount, build a simple box out of the 1"x1" strips of wood. Attach to the face of the inner box.
Glue all strips to ensure the sand doesn't come out.
I can link you to some of my build threads where I did sand fill in some of my baffles if you'd like.
There was a fellow that built a very large subwoofer and used the method of sand fill I'm referring to with those spacer strips. I'll see if I can find it, but it's been a while since I saw it.
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Can't believe I found it that quick.
Check >>this thread<< (http://www.audiocircle.com/index.php?topic=53675), that should give you an idea of the "box in a box", with sand in between.
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Thanks Bob, that makes sense.
What do you think about mixing the sand into casting epoxy and pouring that between the walls? "Epoxy Granite" or "mineral casting." It's supposed to damp the vibes very well, originally used on machine tools to damp metal vibes during ultra-precision machining. Same concept as "cultured marble."
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I know that's what Vapor does (because I 'busted him') while he was doing it. :rofl:
So there's some merit to, for sure.
The thought behind the sand being "free' and able to move, is that the vibrations created by the drivers will cause the sand particles to resonate, thereby absorbing the vibrations.
That's the way Hawthorne and GR Research do it.
So....Who is doing it the correct way??
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I was hoping you would tell me!
I think the correct way is the cheaper and easier way - dry sand! Casting epoxy is expaaaaansive!
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I think the correct way is the cheaper and easier way - dry sand! Casting epoxy is expaaaaansive!
"Yes", that is the way I do it, and the exact reason why I do it that way. :thumb:
Although, my opinion will be poo-poo'd, as I'm not a real speaker builder, but I have slept in a Holiday Inn Express. :lol:
Bob
p.s. By the way....I fixed the link in post #51 to the sand filled sub from GR Research.
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We know Abbie is the speaker builder in the family.
Scotty
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The legacy I've created precedes me. 8)
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Bumping this back to life for an update, if anybody cares.
I found the cause of the mid bass blurring that I mentioned above. It was resonance in the woofer coil. I connected the amp to the midwoofer directly and the problem disappeared. The problem was some resonance in the crossover circuit due to the high Q of the series woofer coil. A friend advised me to put a damping resistor across the coil to reduce the Q of the coil and stop any ringing it might have. It took a few tries to find the resistor value that did not alter the woofer voltage at the crossover freq, but I did find it and the woofer sounds clearer and calmer now. It is easier to concentrate on the music, there was a busyness, clatter that the coil damping has removed. The blooming of voices at 200Hz is mostly gone. What remains I can now hear, due to the added clarity, is just proximity effect from cardioid mics. Before it just sounded like distortion that could be coming from anywhere.
But I really liked how the woofer responded to the direct connect to the amp. The SB acoustics Satori woofer combined with Sol's I-60 amp with JPS Superconductor wire between them was impressive. No wonder this the Wilson's new main midrange driver. The bass control and overall clarity was much better than with the passive crossover, even though I am using huge 10ga coil. So I'm gonna try some active crossover experiments with the speakers. I'll start a new thread for that when I get something happening.
I also designed a new floor-standing box for the Kairos, which has Qtc of .5. I like tight bass and I cannot lie. I also bought some 11" woofers to build a 3 way version and I have the box designed for that too. Active crossovers will make developing a 3way easier in some ways, and give me some benefits that passive crossovers can't touch, but I'm drawn to the challenge of doing a 3 way passive crossover also. Just pipe dreaming now.
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You never cease to amaze me Richidoo. :thumb: Whenever to start up that next project, please take lots of pix along the way.
SN
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Sho'nuff, Bill! Thanks :thumb:
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Rich could there be an inductance issue with the bass caused by the crossover as well ?
charles
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Rich, from my experience, or at least what my mentors have shared with me is that the ringing usually occurs with higher value coils. What XO frequency and coil value are you using?
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Rich could there be an inductance issue with the bass caused by the crossover as well ?
Inductance is a necessary evil, it's the only way we know how to make speaker level crossovers. Inductor coil in the woofer filter makes the low pass filter work, but there is a cost, although I chose the best coils I could find to minimize that issues. The resonance was probably a combination of 2 coils (filter and VC) plus the cap. The resistor seems to have really helped a lot by damping the filter coil. I'm pretty happy with how it sounds now, but you know how it goes a month from now start hearing another problem. :rofl: Compared to the active amp experiment, even the best coil has its issues. The driver's voice coil has induction, which serves to roll off the high frequencies. This canbe used to advantage and some 70s era drivers were designed with higher inductance so they wouldn't need a low pass filter at all. These days, VC inductance is naughty and they try to reduce it to let the crossover filter do all the work. My woofer, the SB Acoustics Satori has very low inductance, it's impedance curve is dead flat out to 10kOhms. So it sounds like a full range driver with rising FR. A little contour network to flatten it out and it would sound pretty good! No resonance breakup to speak of. It is a papyrus fiber cone, or something weird like that.
Rich, from my experience, or at least what my mentors have shared with me is that the ringing usually occurs with higher value coils. What XO frequency and coil value are you using?
Thanks Jim. You are right, it IS a relatively large value coil, which is used to create full 6dB of baffle step correction, necessary to make this little woofer sound bigger than it is. I can't disclose the actual part value in public because it is IP of Meniscus. The crossover frequency is 1900Hz.
Rich
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Hello, all.
Rich,
Thank you for this thread. It's whetted my appetite to finish my Adelphos project sooner rather than later. I'm psyched to actually hear them. How many hours of break in can I look forward to--100 hours? More? I love how you used the Baltic Birch plywood over MDF or my choice of pre-finished plywood. Man, I wish I owned a table saw. I'm sure my wife would not notice if one suddenly appeared.... :rofl:
I suspect I was on my way to making a couple mistakes with how I'm constructing the cabinets. I definitely need to brace the sides. My largest coil is a tad smaller than yours, but I was planning on running a wood dowel from the bottom of the coil to the top of the cabinet as a vertical brace. Now I understand I can do it without creating a problem. Boy, have I got a lot to learn about speakers!
I think I need to read all the other DIY speaker threads now.
Michael
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Hi Michael,
100 hours should be enough. My break in was uneventful, didn't notice (or is it don't remember?) much change during break -in. But it will open up, sound more liquid and play lower after break in. The sound may change unpredictably during this time, so don't be surprised if it gets bad for a short while.
Check your crossover wiring before startup, and start with very low volume just to make sure it sounds right before cranking it up. You don't want tweeter trying to play woofer's part.
I do love my table saw. I have ridgid 10" contractor saw, about 12 years old. Dewalt makes a nice portable saw if you need to hide it when not in use. Very handy! But it leads to endless projects.