While I did see Chuck55's e-mail, I did not know to look for it from his post here. I do not check this thread. I unsubscribed a long time ago. I have not been thinking about the modifications I started this thread with for a long time.
In that time some things have changed. If you are considering a modification for one of the Tang Band transducers, pay close attention to the model number. If the model number has changed from a "S" to a "SD" or "S" to a "SB" and so on, do not attempt the modification.
Most of these changes have been because of a change in the supplier of die cast baskets. The new baskets are taller (or deeper) and require the use of a longer VC former. I have just posted an examination of how the longer VC former changes the performance of the W4-657SB on another thread. The longer VC former has changed the performance of every transducer I have tested. And the change has been for the worse. As the performance of the new transducer versions are significantly different from the original, modifying the new version does not produce the results as modifying the original.
Most of the stamped baskets have stayed the same. It may still be safe to modify those as described. Again, look closely for the addition of or change in letters of the model number.
If the model number has changed, then the modification had an expiration date that has passed.
Lastly, Tang Band claims many things about their transducers. Some matter and some do not. For example "PPM" simply means polypropylene material. There are no minerals added to it. Why they could not have simply said polypropylene or even PP I do not know. After all, they do not say paper material or metal material.
Mark
In that time some things have changed. If you are considering a modification for one of the Tang Band transducers, pay close attention to the model number. If the model number has changed from a "S" to a "SD" or "S" to a "SB" and so on, do not attempt the modification.
Most of these changes have been because of a change in the supplier of die cast baskets. The new baskets are taller (or deeper) and require the use of a longer VC former. I have just posted an examination of how the longer VC former changes the performance of the W4-657SB on another thread. The longer VC former has changed the performance of every transducer I have tested. And the change has been for the worse. As the performance of the new transducer versions are significantly different from the original, modifying the new version does not produce the results as modifying the original.
Most of the stamped baskets have stayed the same. It may still be safe to modify those as described. Again, look closely for the addition of or change in letters of the model number.
If the model number has changed, then the modification had an expiration date that has passed.
Lastly, Tang Band claims many things about their transducers. Some matter and some do not. For example "PPM" simply means polypropylene material. There are no minerals added to it. Why they could not have simply said polypropylene or even PP I do not know. After all, they do not say paper material or metal material.
Mark
Does anyone have the links to mods for the PPM W4-656 cone?
The links don't work anymore.
I listened to the stock paper cone W4-654 and, excluding deeper bass, it is not as good as my W3-871s. The basic problem is it lacks life. Transients are dulled. After an hour my ear started to hurt so there is some nasty distortion with the stock driver. While I would expect the mods to reduce distortion and give some improvement to clarity, I don't think the "dead" sound can be fixed. It is similar to GR Research's M-130 driver.
Just to make sure it wasn't the lack of bass, I put on some Pretenders acoustic music with not much bass. Yup, same problem. My W3-871s is flat to 80Hz, BTW.
The only measurement I can point to is the bad Bl to Mmass ratio. For example, the M-130 is 5.37:7.72 g. The W4-654 is 4.4:4 g.
Some other driver which have potential and may be better than the W4-654 are:
Parts Express #295-010 Dayton 5".
Pioneer 290-010 4 1/2" (also from Parts Express)
Tang-Band W4-616s.
I have heard this driver in stock form and it is much better than the W4-654 but the breakups are even worse.
All these drivers would need some mods to reduce HF breakups.
The links don't work anymore.
I listened to the stock paper cone W4-654 and, excluding deeper bass, it is not as good as my W3-871s. The basic problem is it lacks life. Transients are dulled. After an hour my ear started to hurt so there is some nasty distortion with the stock driver. While I would expect the mods to reduce distortion and give some improvement to clarity, I don't think the "dead" sound can be fixed. It is similar to GR Research's M-130 driver.
Just to make sure it wasn't the lack of bass, I put on some Pretenders acoustic music with not much bass. Yup, same problem. My W3-871s is flat to 80Hz, BTW.
The only measurement I can point to is the bad Bl to Mmass ratio. For example, the M-130 is 5.37:7.72 g. The W4-654 is 4.4:4 g.
Some other driver which have potential and may be better than the W4-654 are:
Parts Express #295-010 Dayton 5".
Pioneer 290-010 4 1/2" (also from Parts Express)
Tang-Band W4-616s.
I have heard this driver in stock form and it is much better than the W4-654 but the breakups are even worse.
All these drivers would need some mods to reduce HF breakups.
Hello Mark
It is good to see you back and experimenting with drivers.
I have conducted some of your suggestions on Fostex FE127 drivers and been very impressed.
You provide a very good service to the DIY comunity and I thank you and hope you keep up the effort. Please contiune to improve the quality of sound we have all come to love.
Thanks again
It is good to see you back and experimenting with drivers.
I have conducted some of your suggestions on Fostex FE127 drivers and been very impressed.
You provide a very good service to the DIY comunity and I thank you and hope you keep up the effort. Please contiune to improve the quality of sound we have all come to love.
Thanks again
Anyone have a picture of how these arcs are placed on the driver? It is not clear just going by the verbal description.
Also, where do I find "Gem Tac"? I found "Fabri-Tac" at Joanne Fabric. It is clear, is this the same stuff?
Finally do you think a syringe with a .03" I.D. needle would work for laying down the required 1mm bead of Gem Tac?
Thanks
What he meant by that is that DESIGNING the modifications is extremely complex. Once the modifications are discovered, the implementation is far simpler.
Now that models have changed, and this thread is old... Which 3 inch driver should we use?
Is the W3-871 (the one currently at Parts Express) good? How about the W3-881SJ?
I agree that this thread is old. It would be fine with me if this thread was retired.
When I first posted the modifications I did not realize how unstable Tang Band designs (for a given model number) were going to be and that Parts Express was not going to inform customers when the model numbers changed.
I recently spoke with a technical support person (named Chris) at Parts Express who told me that the 881 SD had progressed through the 881SE, the 881SF, and so on until we are now at the 881SJ.
Has there been any meaningful changes made to this transducer as its model number has changed? Chris had no idea. And since PE had not bothered to inform customers that the model numbers were changing, I certainly did not.
Mark
When I first posted the modifications I did not realize how unstable Tang Band designs (for a given model number) were going to be and that Parts Express was not going to inform customers when the model numbers changed.
I recently spoke with a technical support person (named Chris) at Parts Express who told me that the 881 SD had progressed through the 881SE, the 881SF, and so on until we are now at the 881SJ.
Has there been any meaningful changes made to this transducer as its model number has changed? Chris had no idea. And since PE had not bothered to inform customers that the model numbers were changing, I certainly did not.
Mark
Whenever TangBand makes any change, the number is changed. It could be just change in what clue is used, etc. Recent move to Rohs compliant models have changed all numbers to indicate such. I think all Parts Express needs to do is call TB and ask. They normally are pretty precise in this aspect.
I have ordered modified versions of their drivers to my requirements. Even the version number they supply my has a version letter, if they have changes after my version, the letter is just rolled. This is a very standard way of maintaining configuration control. In recent contact with them I did ask about driver number update, and their response was tha last round of version change was due to some material changes to be RoHs compliant.MarkMcK said:
Interesting, so even if your explanation is the correct one, it seems to be left to the customer to determine if the changes have produced performance differences.
It just makes it very difficult to have confidence that the transducer I buy today performs the same as the transducer I bought six months ago. And if you are trying for the precision that I achieve with my modifications, it is necessary that there be some consistency.
Mark
It just makes it very difficult to have confidence that the transducer I buy today performs the same as the transducer I bought six months ago. And if you are trying for the precision that I achieve with my modifications, it is necessary that there be some consistency.
Mark
Should, could, would. The Parts Express person I spoke with (Chris) stated that the model number was changing every time they reordered. Because Parts Express orders so many model numbers at one time, they may be able to order less of a given model than you or I could. That means that the life of a given model number can be short.
Mark
I know what you mean. sometimes I can get two drivers that vary in the CSD, and can't figure out what the hell is going on. That's when I ask specifically whether certain things had changed or not. Can you imagine adding a shorting ring without telling first?MarkMcK said:
But for most of the part, I cannot imagine the numbers changing too often unless Parts Express is ordering them less than twice a year. I do recall they wanted to streamline the production line a few years back. Probably there might have been more frequent changes then.
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