Hi Sheldon,
Your woofers were an extreme case of things not going well. Right before yours I ran out of motors for the Lambdas with copper faraday. I had a guy working for me doing the machining and things just didn't work well on that. It left me with no motors and nobody to make them. I'm capable of doing the machining, one of the many hats i wear, but time is a factor. If it was just an issue of machining parts for your two motors I could probably do that in an hour or so. The problem comes in when they need to be plated. The plate shop needs 60pcs minimum for me to take them there. I'd say by the time I face off 60 back plates on both sides, bore the hole to fit the pole, turn down the pole to fit the copper and pressfit into the backplate I'd have a good 20-30 hours into it solid. Then the poles need to go in the freezer so they shrink enough to press fit. They get sized 3-5thousandths larger than the hole, shrunk down, and then pressed. This assures a pressfit that will never come apart. After that the copper tube on the inside needs to be sprayed with accelerator and the pole with the adhesive. The copper gets pressed on and the glue cures. Once that is done they get put back in the lathe and the top of the pole is drilled and tapped to accept the phase plug. All in all I'd have more than a full 40 hour week to get the 60poles done. IT's taken me this long to finally get those finished up.
I'm looking into finding some kind of small tank method to plate pieces one at a time by hand. The problem is that I'm moving the shop home and the plating isn't something I can probably do here.
Your drivers did ship out last week as you have noticed and I covered the shipping cost. Thank you for behing honest with me too and letting me know I never charged you for it. With the way my books are right now I probably woudl never have cought it. haha
Let me know how things work out for you. Send some pics of your project. I'm trying to get the gallery fixed on the website right now.
John
Your woofers were an extreme case of things not going well. Right before yours I ran out of motors for the Lambdas with copper faraday. I had a guy working for me doing the machining and things just didn't work well on that. It left me with no motors and nobody to make them. I'm capable of doing the machining, one of the many hats i wear, but time is a factor. If it was just an issue of machining parts for your two motors I could probably do that in an hour or so. The problem comes in when they need to be plated. The plate shop needs 60pcs minimum for me to take them there. I'd say by the time I face off 60 back plates on both sides, bore the hole to fit the pole, turn down the pole to fit the copper and pressfit into the backplate I'd have a good 20-30 hours into it solid. Then the poles need to go in the freezer so they shrink enough to press fit. They get sized 3-5thousandths larger than the hole, shrunk down, and then pressed. This assures a pressfit that will never come apart. After that the copper tube on the inside needs to be sprayed with accelerator and the pole with the adhesive. The copper gets pressed on and the glue cures. Once that is done they get put back in the lathe and the top of the pole is drilled and tapped to accept the phase plug. All in all I'd have more than a full 40 hour week to get the 60poles done. IT's taken me this long to finally get those finished up.
I'm looking into finding some kind of small tank method to plate pieces one at a time by hand. The problem is that I'm moving the shop home and the plating isn't something I can probably do here.
Your drivers did ship out last week as you have noticed and I covered the shipping cost. Thank you for behing honest with me too and letting me know I never charged you for it. With the way my books are right now I probably woudl never have cought it. haha
Let me know how things work out for you. Send some pics of your project. I'm trying to get the gallery fixed on the website right now.
John
Thanks John,
The woofers arrived in good shape. Very nice too. It was a nice surprise that they are still shipping with the phase plugs. I know they sound great, because I've already tested the 15"er's. They look very nice too.
Doing all the operations involved in construction speakers along with all the other stuff that goes with running is business, and having to do it alone is a tall order. Sounds like you are digging out and getting back to level ground. We'd all like to see you successful. Not so many items of this quality available to DIY'ers.
I've described some of what I'm doing in a thread on Unity Horns. I'll post pics when I get near the finish. Should be done in a couple of months.
One question: Do you have specs. posted anywhere?
Best Wishes,
Sheldon
The woofers arrived in good shape. Very nice too. It was a nice surprise that they are still shipping with the phase plugs. I know they sound great, because I've already tested the 15"er's. They look very nice too.
Doing all the operations involved in construction speakers along with all the other stuff that goes with running is business, and having to do it alone is a tall order. Sounds like you are digging out and getting back to level ground. We'd all like to see you successful. Not so many items of this quality available to DIY'ers.
I've described some of what I'm doing in a thread on Unity Horns. I'll post pics when I get near the finish. Should be done in a couple of months.
One question: Do you have specs. posted anywhere?
Best Wishes,
Sheldon
Sheldon said:
my good friend thylantyr has been hosting these for people like us for 3 yrs or so now
http://home.pacbell.net/lordpk/lambda/
BAM said:
it's such a pretty driver... the phase plugs on mine are the longer beefier ones than this
An externally hosted image should be here but it was not working when we last tested it.
Four of the most recently shipped IB15" drivers had the following T/S Parameters. The numbers in ( ) are the published specs. Hopefully John will comment on this....
fs 32.24 (16)
Qms 4.43 (4.9)
Qes 1.2773 (.48)
Qts 1.0201 (.44)
VAS 190.57 (467)
Re 5.50 (5.6)
Le 2.906 (1.25)
Mms 132.63 (218)
BL 10.743 (16)
fs 32.24 (16)
Qms 4.43 (4.9)
Qes 1.2773 (.48)
Qts 1.0201 (.44)
VAS 190.57 (467)
Re 5.50 (5.6)
Le 2.906 (1.25)
Mms 132.63 (218)
BL 10.743 (16)
Have you actually contacted John about getting replacement woofers? I have never known him to not take action on a complaint like this. When two IB15 woofers had glue joint trouble, he tested whole batches to make sure they were structurally sound. This isn't right to blast the guy publicly for these issues if you, or the interested party, hasn't contacted John.
ThomasW said:
Hi Thomas,
Who did the measurements, and what were the conditions and equipment. I see a few things that cannot be right. First off, Mms cannot be measured correct. The physical mass of the cone should be about 100grams, plus the coil around 65, plus half surround, spider, glue, dustcap, plus the loading. Mmd should be a little less than Mms because it is the physical weight only.
Also, Vas is much stiffer than it should be. The spiders do have a very stiff ring of resin on them towards the middle, but that shouldn't affect things that much. My initial guess is that the method(delta mass) to measure Vas and Cms was a mass added method. This is often not very reliable. Both with the woofer tester and with praxis I used to get erratic results. A much more reliable method is the delta volume where you take measurements in different known volumes.
Although everything looks off by a lot, putting the Mms in the approximate range it should be in shifts parameters back to where it should be. Cms being about .44 instead of the .19 that it measured at shifts everything else dead on. Both of those parameters would be wrong together as I said if the mass added method wasn't perfect. The mass as measured cannot be correct because the parts alone weigh much more than that.
John
People need to understand that I'm a BIG fan of John and his products. If one looks at the IB gallery pages one sees a higher percentage of IB's built using his drivers than any other supplier. However in recent months communications with him have been quite problematic.
Posting publicly was the most expedient way I knew to get this particular situation straightened out. I fully realize posting wasn't the most politically correct approach, but I can't be responsible for providing product information and support when there are issues (real or perceived) with John's drivers. And unfortunately that's the position I'm in when I recommend his products and it's difficult for customers to contact him, which it is....
The testing that I posted was done by one of the people building an IB using 8 of the IB15"s. John's posted the same reply to him on the IB forum.
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