i Mark
I was interested to read your post on the
difference between the 881S and 881SDs. I
have been using the 532s drivers that are
now replaced by the 532sg units. So I wonder
does an 881s= 532s (the 881s being a Parts
Express request from TB for a round basket)?
After the end of a production run for Parts Express
and the commencement of a new production run,
does a 881SD= a 532SG and thus shares the
same 17.5khz issues? Is the change due to
different cone profiling or change somewhere
else? The 657 4" seems to have also been through
an upgrade or "spec change" The kapton former
and magnesium/alu coil being the advertised
alternations.
Now with the alledged arrival of the new
W4-1337S and W4-1320SA drivers with Neo magnets and exotic
cones I wonder if we are seeing real progress or
just trendy new packaging. Time and experiments will
no doubt clarify the situation!
Regards
AnthonyPT
I was interested to read your post on the
difference between the 881S and 881SDs. I
have been using the 532s drivers that are
now replaced by the 532sg units. So I wonder
does an 881s= 532s (the 881s being a Parts
Express request from TB for a round basket)?
After the end of a production run for Parts Express
and the commencement of a new production run,
does a 881SD= a 532SG and thus shares the
same 17.5khz issues? Is the change due to
different cone profiling or change somewhere
else? The 657 4" seems to have also been through
an upgrade or "spec change" The kapton former
and magnesium/alu coil being the advertised
alternations.
Now with the alledged arrival of the new
W4-1337S and W4-1320SA drivers with Neo magnets and exotic
cones I wonder if we are seeing real progress or
just trendy new packaging. Time and experiments will
no doubt clarify the situation!
Regards
AnthonyPT
Tang Band is mixing and matching new parts all the time. There is, however, no evidence that Tang Band has any intent in doing this other than to mix and match new parts. There is no consistency or development "progress" as new models and designs are introduced.
As just a guestimate, I would say that Tang Band produces a worthwhile driver about 10 % of the time. Because TB makes so many drivers, you can find good TB drivers. You just have go through a lot of driver models to find the good ones.
The 881S vs 881SD is a good example. The 881S basket was not available. The available basket is deeper. TB made other changes in the driver so that the parts connect using the deeper basket. This swapping of parts has created a new driver that performs significantly differently than the 881S.
It is clear that TB did not understand why the 881S worked. Without understanding why the combination of parts that made up the 881S worked, they cannot hold the performance when they make changes. This will apply to all other TB drivers. Each model number (even if it is only a added letter) must be viewed as a new and unique driver.
During my three-inch survey I measured two-inch drivers. Both TB and Hi-Vi two-inch drivers lack the high frequency extension of the best three-inch drivers. The two-inch drivers were dying by 15 kHz (or less). Since using a smaller diameter cone brings other problems, why bother since they don't even have equal high frequency extension?
Now, the 532S has always had a 17 to 18 kHz vibration mode problem. It will have that problem (and many more besides) with or without a plug. The 532S was part of my survey and it was rejected. I tested it with and without a plug (at that time the plug version was the 532SH). Also, just because two drivers have problems at similar frequencies does not mean that the trigger is at the same location on the cones.
What I do not know is if Tand Band ever rejects a design. Have they ever put together a driver that they haven't tried to sell?
Good designing and good building,
Mark
As just a guestimate, I would say that Tang Band produces a worthwhile driver about 10 % of the time. Because TB makes so many drivers, you can find good TB drivers. You just have go through a lot of driver models to find the good ones.
The 881S vs 881SD is a good example. The 881S basket was not available. The available basket is deeper. TB made other changes in the driver so that the parts connect using the deeper basket. This swapping of parts has created a new driver that performs significantly differently than the 881S.
It is clear that TB did not understand why the 881S worked. Without understanding why the combination of parts that made up the 881S worked, they cannot hold the performance when they make changes. This will apply to all other TB drivers. Each model number (even if it is only a added letter) must be viewed as a new and unique driver.
During my three-inch survey I measured two-inch drivers. Both TB and Hi-Vi two-inch drivers lack the high frequency extension of the best three-inch drivers. The two-inch drivers were dying by 15 kHz (or less). Since using a smaller diameter cone brings other problems, why bother since they don't even have equal high frequency extension?
Now, the 532S has always had a 17 to 18 kHz vibration mode problem. It will have that problem (and many more besides) with or without a plug. The 532S was part of my survey and it was rejected. I tested it with and without a plug (at that time the plug version was the 532SH). Also, just because two drivers have problems at similar frequencies does not mean that the trigger is at the same location on the cones.
What I do not know is if Tand Band ever rejects a design. Have they ever put together a driver that they haven't tried to sell?
Good designing and good building,
Mark
Hi Mark,
I find that rather suprising that the larger diameter drivers have better HF extension than the smaller (acoustically) cones
. This seems rather counter intuitive. But you did the testing first hand, so I will have to accept this explanation. I saw a test by Zaph of both the 2 and 3 inch drivers (with distortion measurements - which I think is critical), where it appeared that the 2" TB was quite flat across most of its range, but then broke up badly above 15k or so. Are you saying this this is non-correctible using your methods?. I would have to imagine that the smaller drivers have much better off-axis response, but again I could be wrong. Do you have any off-axis or distortion data for your mad.6T drivers?
My main interest in the smaller drivers is that I don't need extension down to 2-300hz, but rather in the 500hz range, where the 2" TB (according to Zaphs data) looks acceptable - for a $13 driver! Below that it distorts badly - as a 2" driver would. But I thought it would give more "tweeter like" response in the upper octaves than a larger cone. Thank you very much for all the info so far!
Zaphs data: http://www.zaphaudio.com/minitest/all.html
Cheers,
AJ
I find that rather suprising that the larger diameter drivers have better HF extension than the smaller (acoustically) cones
. This seems rather counter intuitive. But you did the testing first hand, so I will have to accept this explanation. I saw a test by Zaph of both the 2 and 3 inch drivers (with distortion measurements - which I think is critical), where it appeared that the 2" TB was quite flat across most of its range, but then broke up badly above 15k or so. Are you saying this this is non-correctible using your methods?. I would have to imagine that the smaller drivers have much better off-axis response, but again I could be wrong. Do you have any off-axis or distortion data for your mad.6T drivers?My main interest in the smaller drivers is that I don't need extension down to 2-300hz, but rather in the 500hz range, where the 2" TB (according to Zaphs data) looks acceptable - for a $13 driver! Below that it distorts badly - as a 2" driver would. But I thought it would give more "tweeter like" response in the upper octaves than a larger cone. Thank you very much for all the info so far!
Zaphs data: http://www.zaphaudio.com/minitest/all.html
Cheers,
AJ
Just as a point of explanation, I do not talk about or hawk my commercial products on this (or any other) diy Web site. I know that this Web site has a moderator or two who do, but I don't. I talk about and share the free stuff.
Further, while I will comment on testing programs of other commercial entities, I do not comment upon amateur testers. I can read tests and point out things with published results of commercial sites like Jordan or Manger (and many others). From the people I have talked to about these problems, few are picking up on the clues that suggest something isn't right. And this is for commercial companies where multiple people are involved and those people are paid to do this. Acoustic testing is difficult and there are few standards of testing or presentation of results. Since the professionals are having problems it seems to be too much to ask of diy and so I do not comment at all.
Now, about the smaller diameter drivers with less high frequency extension . . . driver design is not simple. It is extremely complex and few (even loudspeaker transducer manufacturers) have a clue. You cannot understand what is going on simply by reading the books (and text books) about acoustics. For example, if the books were right, then all loudspeaker transducers would roll-off in the high frequencies at a second order rate. This is how the systems are always modeled. A second order system of mass and inductance. Yet it is extremely rare for a driver to roll-off at 12db per octave. Most die at a rate several orders higher. This is a problem for second order modelers in understanding or predicting what a driver will do or what it is capable of doing.
From my experience with a variety of two-inch drivers, I do not recommend two-inch cone drivers. And yes, while I can improve just about any driver, most of the time the improved driver is still not worth using. When a good driver is modified the results can be spectacular, going far beyond anything else. The 881S is a good example. Evaluators would commonly start with the comment that the modified driver sounded unlike anything they had ever heard before. Then they would go on to praise the sound, but often starting with how different it was.
Unfortunately the 881S is gone.
Good designing and good building,
Mark
Further, while I will comment on testing programs of other commercial entities, I do not comment upon amateur testers. I can read tests and point out things with published results of commercial sites like Jordan or Manger (and many others). From the people I have talked to about these problems, few are picking up on the clues that suggest something isn't right. And this is for commercial companies where multiple people are involved and those people are paid to do this. Acoustic testing is difficult and there are few standards of testing or presentation of results. Since the professionals are having problems it seems to be too much to ask of diy and so I do not comment at all.
Now, about the smaller diameter drivers with less high frequency extension . . . driver design is not simple. It is extremely complex and few (even loudspeaker transducer manufacturers) have a clue. You cannot understand what is going on simply by reading the books (and text books) about acoustics. For example, if the books were right, then all loudspeaker transducers would roll-off in the high frequencies at a second order rate. This is how the systems are always modeled. A second order system of mass and inductance. Yet it is extremely rare for a driver to roll-off at 12db per octave. Most die at a rate several orders higher. This is a problem for second order modelers in understanding or predicting what a driver will do or what it is capable of doing.
From my experience with a variety of two-inch drivers, I do not recommend two-inch cone drivers. And yes, while I can improve just about any driver, most of the time the improved driver is still not worth using. When a good driver is modified the results can be spectacular, going far beyond anything else. The 881S is a good example. Evaluators would commonly start with the comment that the modified driver sounded unlike anything they had ever heard before. Then they would go on to praise the sound, but often starting with how different it was.
Unfortunately the 881S is gone.
Good designing and good building,
Mark
Hi Mark,
Thanks for you reply.
Your review of what is going on with Tang Band
when they elect to market specific drivers is
a little surprising or is it? Do some of the
quality control variables come perhaps as a result
of outsourcing? Items like baskets and cones or magnets
of differing strengths due to different not to close
tolerence production runs? I have always found
TB the company to be helpful. Matching drivers
or closer tolerence drivers maybe for some
manufacturers too costly. I recall when
I had my LS3/5a speakers even they had individual
taps on the auto-transformers to match the Kef T27
tweeters to the B110s even after alledged careful
selection of drivers! That was in the 1970s; so
despite the development of exotic cones and other
innovations since then, tight repeatable close tolerance
drivers are still hard to produce in big runs at
reasonable prices?
I was listening to a MTM speaker with "matched" Thiel
ceramic drivers and Raven tweeters over the weekend driven
by Nuforce amps. Close tolerence is very nice at a price!
In your work have you found out of the box drivers
that match relatively closely turn into broken-in
drivers that still match closely?
This whole area of close specking of small drivers
might account for the fact that Bandor makes their own
In-house and it is suggested that Jordan had a spell of
not finding manufacturing results to Ted's satisfaction
for a while before the current production runs.
Regards
AnthonyPT
Thanks for you reply.
Your review of what is going on with Tang Band
when they elect to market specific drivers is
a little surprising or is it? Do some of the
quality control variables come perhaps as a result
of outsourcing? Items like baskets and cones or magnets
of differing strengths due to different not to close
tolerence production runs? I have always found
TB the company to be helpful. Matching drivers
or closer tolerence drivers maybe for some
manufacturers too costly. I recall when
I had my LS3/5a speakers even they had individual
taps on the auto-transformers to match the Kef T27
tweeters to the B110s even after alledged careful
selection of drivers! That was in the 1970s; so
despite the development of exotic cones and other
innovations since then, tight repeatable close tolerance
drivers are still hard to produce in big runs at
reasonable prices?
I was listening to a MTM speaker with "matched" Thiel
ceramic drivers and Raven tweeters over the weekend driven
by Nuforce amps. Close tolerence is very nice at a price!
In your work have you found out of the box drivers
that match relatively closely turn into broken-in
drivers that still match closely?
This whole area of close specking of small drivers
might account for the fact that Bandor makes their own
In-house and it is suggested that Jordan had a spell of
not finding manufacturing results to Ted's satisfaction
for a while before the current production runs.
Regards
AnthonyPT
3 hours for 5 drivers is less than I thought, very doable.
I was a little puzzled that “the problems are complex, the modification is complex”. .
But it’s just cutting four Vs, then sealing back up with rubber compound.
The trickiest bit must be sealing cuts 100% with a toothpick – would something else work more easily eg a matchstick?
I also wonder whether this technique would work with other speakers with resonances . .
Cheers
I was a little puzzled that “the problems are complex, the modification is complex”. .
But it’s just cutting four Vs, then sealing back up with rubber compound.
The trickiest bit must be sealing cuts 100% with a toothpick – would something else work more easily eg a matchstick?
I also wonder whether this technique would work with other speakers with resonances . .
Cheers
http://madspeaker.com/Projects/4-656/656Sgluemod.htm
Uh... I think you maybe thinking of a different driver modification. The 656 just requires some Gemtak, phase plug, and notch filter.
Joe
Uh... I think you maybe thinking of a different driver modification. The 656 just requires some Gemtak, phase plug, and notch filter.
Joe
Tang Band - What is a PPM cone?
Just trying to0 figure out what PPM means? Anyone have an idea? My plan is to use the W6-623, W6-658A or the W6-789 which all use the PPM cone material. Is this paper? Polypropylene? Or something more exotic? My plan is to cross them over to a Ribbon tweeter. And to use a reflex design with passive radiator for low end extension. I am interested in these filters you are using as well. I'll have to spice those, and see where I get with that. Thanks! Looks like a great forum! Very imformative. Gene (Tektronix Design Engineer)
Just trying to0 figure out what PPM means? Anyone have an idea? My plan is to use the W6-623, W6-658A or the W6-789 which all use the PPM cone material. Is this paper? Polypropylene? Or something more exotic? My plan is to cross them over to a Ribbon tweeter. And to use a reflex design with passive radiator for low end extension. I am interested in these filters you are using as well. I'll have to spice those, and see where I get with that. Thanks! Looks like a great forum! Very imformative. Gene (Tektronix Design Engineer)
Are there mods to the metal 657 driver or is this just a mix-up with the PPM 656 poly cone?
Are there any links to modding the 654 / 657 drivers? The old links don't work any more.
I got the 654 today so am eager to give this a try.
Any sources for the POR-A-MOLD 555 or a source to buy just a small amount?
Thanks
Are there any links to modding the 654 / 657 drivers? The old links don't work any more.
I got the 654 today so am eager to give this a try.
Any sources for the POR-A-MOLD 555 or a source to buy just a small amount?
Thanks
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