[fid]

Hello,
Can you please suggest hi-quality tweeters to replace the T33s for the
kef 107s? I was thinking at the Scan-Speak D2905/9500. Could the
faceplate of these tweeters be swapped to fit different speakers? I
appreciate any inputs.
Thank you

[fid]

On Feb 19, 7:27 pm, François Yves Le Gal wrote:
On 19 Feb 2007 16:13:44 -0800, "fid" wrote:

Can you please suggest hi-quality tweeters to replace the T33s for the
kef 107s? I was thinking at the Scan-Speak D2905/9500. Could the
faceplate of these tweeters be swapped to fit different speakers? I
appreciate any inputs.

Just like any other quality speaker, the 107 is a system. You can't change
the tweeter w/o modifying the filter and basically redesigning a new
speaker. Ditto for the face plates, which are an integral part of the
design. Modifying any driver is a very complex job.

BTW, the 107 is well balanced in stock form, and the T33's are quite nice
tweeters.

Nothing wrong with the T33 itself. The problem is that after so many
years of daily usage I am afraid the they are wearing off. That's the
reason why I was meditating the possibility of replacement.

[fid]

On Feb 19, 9:45 pm, François Yves Le Gal wrote:
On 19 Feb 2007 17:03:29 -0800, "fid" wrote:

The problem is that after so many
years of daily usage I am afraid the they are wearing off.

Properly usedtweetersdon't really wear. OTOH the T33's use Ferrofluid,
which sometimes can harden and become problematic .

I don't know much about speaker's subcomponents and replacements. I
spoke to a costumer service at Madisound about the possibility of
replacing the tweeters. When I asked him about scanspeak he wasn't
favorable about them. He said: "The D2905/9500 is a classic high end
tweeter. All 1" Scan-Speak tweeters have a metal face plate...so it
would be difficult to modify". Can anyone explain this? Don't all the
tweeters come with a removable faceplate (kef 107 uses square
faceplate)? Thanks

[bassett]

"fid" wrote in message


I don't know much about speaker's subcomponents and replacements. I
spoke to a costumer service at Madisound about the possibility of
replacing the tweeters. When I asked him about scanspeak he wasn't
favorable about them. He said: "The D2905/9500 is a classic high end
tweeter. All 1" Scan-Speak tweeters have a metal face plate...so it
would be difficult to modify". Can anyone explain this? Don't all the
tweeters come with a removable faceplate (kef 107 uses square
faceplate)? Thanks


The Scan Speak D2905-950000 while a nice Tweeter, would not be considered
hi-end , [hundred and fifty bucks aust] Face plates are all in the 104
// 105 mm range, and are an integeral part of the tweeter and as such not
removable.

If your looking for replacements consider the new Scan Speak
D2905-990000 Revelator, this is particularly good as a replacement as it
has
a 130 mm faceplate, and will cover up most if not all old fitting holes
There priced at two fifty dollars

If you want Hi-end the Scan speak super tweeter [2k- 80khz] R2904-700000.
prices range between four and five hundred depending on where you get them.
Face plate size is again 104mm

Then we have the Twin Ribbon 100khz super tweeter from Jas Audio at $1500
each.
and very nice they are too.

bassett

[fid]

On Feb 21, 4:37 am, "bassett" wrote:
"fid" wrote in message

I don't know much about speaker's subcomponents and replacements. I
spoke to a costumer service at Madisound about the possibility of
replacing thetweeters. When I asked him about scanspeak he wasn't
favorable about them. He said: "The D2905/9500 is a classic highend
tweeter. All 1" Scan-Speaktweetershave a metal face plate...so it
would be difficult to modify". Can anyone explain this? Don't all the
tweeterscome with a removable faceplate (kef 107 uses square
faceplate)? Thanks

The Scan Speak D2905-950000 while a nice Tweeter, would not be consideredhi-end, [hundred and fifty bucks aust] Face plates are all in the 104
// 105 mm range, and are an integeral part of the tweeter and as such not
removable.

If your looking for replacements consider the new Scan Speak
D2905-990000 Revelator, this is particularly good as a replacement as it
has
a 130 mm faceplate, and will cover up most if not all old fitting holes
There priced at two fifty dollars

If you wantHi-end the Scan speak super tweeter [2k- 80khz] R2904-700000.
prices range between four and five hundred depending on where you get them.
Face plate size is again 104mm

Then we have the Twin Ribbon 100khz super tweeter from Jas Audio at $1500
each.
and very nice they are too.

bassett

Thank you for posting your input. You are suggesting Scan Speak
D2905-990000. But does it have a removable faceplate? Please note
that my kefs have an unusual square plate.
However, why would I get a tweeter that goes as hi as 100Hz when the
human hearing is virtually def in those frequencies?

Thanks
Fid

[Trevor Wilson]

"fid" wrote in message
oups.com...
On Feb 19, 9:45 pm, François Yves Le Gal wrote:
On 19 Feb 2007 17:03:29 -0800, "fid" wrote:

The problem is that after so many
years of daily usage I am afraid the they are wearing off.

Properly usedtweetersdon't really wear. OTOH the T33's use Ferrofluid,
which sometimes can harden and become problematic .

I don't know much about speaker's subcomponents and replacements.

**Then forget about replacing tweeters. Just use the OEM parts. You cannot
substitute *any* drivers in a system, without intimate knowledge of the
characteristics of the replacements, the crossover values and you need to
know EXACTLY what you are doing. However, you'll likely ignore this, because
you've been told this before.

Think of it this way:

Would you try to put a Porsche fuel injection system onto a Toyota Corolla
in the hope that you'll gain better performance?


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[AZ Nomad]

On Wed, 28 Feb 2007 10:28:37 +1100, Trevor Wilson wrote:



"fid" wrote in message
roups.com...
On Feb 19, 9:45 pm, François Yves Le Gal wrote:
On 19 Feb 2007 17:03:29 -0800, "fid" wrote:

The problem is that after so many
years of daily usage I am afraid the they are wearing off.

Properly usedtweetersdon't really wear. OTOH the T33's use Ferrofluid,
which sometimes can harden and become problematic .

I don't know much about speaker's subcomponents and replacements.

**Then forget about replacing tweeters. Just use the OEM parts. You cannot
substitute *any* drivers in a system, without intimate knowledge of the
characteristics of the replacements, the crossover values and you need to
know EXACTLY what you are doing. However, you'll likely ignore this, because
you've been told this before.

Tweeters typically are sealed and not tuned w/ the cabinet. As long as the
frequency response of the replacement tweeter is adequate, the main problem is
matching levels. Get a replacement tweeter that has the same sensativity and
the replacement will work.

[Arny Krueger]

"François Yves Le Gal" wrote in
message
On Wed, 28 Feb 2007 15:54:18 GMT, AZ Nomad
wrote:

Tweeters typically are sealed and not tuned w/ the
cabinet.

Baffle diffraction anyone?

Crossovers, anyone?

As long as the
frequency response of the replacement tweeter is
adequate, the main problem is matching levels. Get a
replacement tweeter that has the same sensativity and
the replacement will work.

Nope. Tweeters can display superficially identical
sensitivities and responses while having very different
electrical and/or acoustical properties.

Agreed. This is a KEF 107, not a FungooTek computer speaker. It is
definately worth it to do it *right*.

I can't believe that KEF doesn't have a replacement tweeter for sale at
price that is vastly less costly than the used equipment value of the
speaker.

[AZ Nomad]

On Wed, 28 Feb 2007 17:21:22 +0100, François Yves Le Gal wrote:


On Wed, 28 Feb 2007 15:54:18 GMT, AZ Nomad
wrote:

Tweeters typically are sealed and not tuned w/ the cabinet.

Baffle diffraction anyone?

As long as the
frequency response of the replacement tweeter is adequate, the main problem is
matching levels. Get a replacement tweeter that has the same sensativity and
the replacement will work.

Nope. Tweeters can display superficially identical sensitivities and
responses while having very different electrical and/or acoustical
properties.

You should have no problem naming some of these properties. Otherwise,
one might think that you're talking out of your ass.

[Arny Krueger]

"AZ Nomad" wrote in message

On Wed, 28 Feb 2007 17:21:22 +0100, François Yves Le Gal
wrote:


On Wed, 28 Feb 2007 15:54:18 GMT, AZ Nomad
wrote:

Tweeters typically are sealed and not tuned w/ the
cabinet.

Baffle diffraction anyone?

As long as the
frequency response of the replacement tweeter is
adequate, the main problem is matching levels. Get a
replacement tweeter that has the same sensativity and
the replacement will work.

Nope. Tweeters can display superficially identical
sensitivities and responses while having very different
electrical and/or acoustical properties.

You should have no problem naming some of these
properties. Otherwise,
one might think that you're talking out of your ass.

Chill man, François has it right.

He says:

"Tweeters can display superficially identical sensitivities" which
basically means dB/watt.

"responses" which means general frequency response, which basically means so
many Hz to so many Hz within so many dB.

"while having very different electrical (properties)" which basically means
impedance curve.

and

"(very different) acoustical properties" which bascially means things like
directivity.

All very true.

[Trevor Wilson]

"AZ Nomad" wrote in message
...
On Wed, 28 Feb 2007 10:28:37 +1100, Trevor Wilson
wrote:



"fid" wrote in message
groups.com...
On Feb 19, 9:45 pm, François Yves Le Gal wrote:
On 19 Feb 2007 17:03:29 -0800, "fid" wrote:

The problem is that after so many
years of daily usage I am afraid the they are wearing off.

Properly usedtweetersdon't really wear. OTOH the T33's use Ferrofluid,
which sometimes can harden and become problematic .

I don't know much about speaker's subcomponents and replacements.

**Then forget about replacing tweeters. Just use the OEM parts. You cannot
substitute *any* drivers in a system, without intimate knowledge of the
characteristics of the replacements, the crossover values and you need to
know EXACTLY what you are doing. However, you'll likely ignore this,
because
you've been told this before.

Tweeters typically are sealed and not tuned w/ the cabinet.

**Correct. That is 10% of the story. There are more important issues to be
concerned with. Impedance levels dictate crossover points. The 107 has Zobel
networks on each driver, which are intimately associated with the impedance
characteristics of the driver. Hoping to find a replacement tweeter with an
identical impedance curve is bordering on impossible. That said, someone
with plenty of experience and some decent test equipment COULD do the job.
However, anyone who has to ask questions here, clearly is well out of their
depth. As is anyone who makes nonsensical, glib statements like yours.

As long as the
frequency response of the replacement tweeter is adequate, the main
problem is
matching levels.

**Wrong. That is another 10% of the problem.

Get a replacement tweeter that has the same sensativity and
the replacement will work.

**Work? Certainly. Work well? Not likely. You're talking out of your arse.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[ScottW]

On Feb 19, 4:13 pm, "fid" wrote:
Hello,
Can you please suggest hi-quality tweeters to replace the T33s for the
kef 107s? I was thinking at the Scan-Speak D2905/9500. Could the
faceplate of these tweeters be swapped to fit different speakers? I
appreciate any inputs.
Thank you

Heres a thread on replacing T33s in KEF104s.

http://audiokarma.org/forums/showthr...t=76529&page=2

One guy used a VIFA MG27 available from Madisound for ~$22 and claims
good results.
Worth a shot at that price.

ScottW

[Arny Krueger]

"fid" wrote in message
oups.com...
Hello,
Can you please suggest hi-quality tweeters to replace the T33s for the
kef 107s? I was thinking at the Scan-Speak D2905/9500. Could the
faceplate of these tweeters be swapped to fit different speakers? I
appreciate any inputs.

Check this tech info about what tweeters were used in various products.
Perhaps you can find one of them for a reasonable price:

http://www.hifiloudspeakers.info/Ana...erSystems.html

[avidlistener]

On Feb 19, 4:13 pm, "fid" wrote:
Hello,
Can you please suggest hi-quality tweeters to replace the T33s for the
kef 107s? I was thinking at the Scan-Speak D2905/9500. Could the
faceplate of these tweeters be swapped to fit different speakers? I
appreciate any inputs.
Thank you

Unless you are prepared to re-enineer your speakers, it is best to use
the same model, since the speaker system's xover was designed for the
T33, nothing else will work exactly the same. Things like the rolloff
of he tweeter and how it meshs with the driver handling the lower
frequency range will almost surely be different.

Xover design is like most things in speaker design, a compromise,
there is no drop in replacement other than the driver that the system
came with.

Unless you are willing to invest in the equipment neccessary to model
and measure the results of any driver changes, then it is best to
leave things as they were originally designed.

[Arny Krueger]

"François Yves Le Gal" wrote in message
...
On Wed, 28 Feb 2007 11:36:39 -0500, "Arny Krueger"
wrote:

I can't believe that KEF doesn't have a replacement tweeter for sale at
price that is vastly less costly than the used equipment value of the
speaker.

Kef has become another empty shell with basically badge-engineered Chinese
products.

So it seems. I did some research on the subject and came up with my other
post about possible ways to obtain T33s.

[bassett]

"fid" wrote in message
oups.com...
On Feb 21, 4:37 am, "bassett" wrote:
"fid" wrote in message

I don't know much about speaker's subcomponents and replacements. I
spoke to a costumer service at Madisound about the possibility of
replacing thetweeters. When I asked him about scanspeak he wasn't
favorable about them. He said: "The D2905/9500 is a classic highend
tweeter. All 1" Scan-Speaktweetershave a metal face plate...so it
would be difficult to modify". Can anyone explain this? Don't all the
tweeterscome with a removable faceplate (kef 107 uses square
faceplate)? Thanks


If your looking for replacements consider the new Scan Speak
D2905-990000 Revelator, this is particularly good as a replacement as
it
has a 130 mm faceplate, and will cover up most if not all old fitting
holes
There priced at two fifty dollars

If you wantHi-end the Scan speak super tweeter [2k- 80khz] R2904-700000.
prices range between four and five hundred depending on where you get
them.
Face plate size is again 104mm

Then we have the Twin Ribbon 100khz super tweeter from Jas Audio at
$1500
each.
and very nice they are too.

bassett

Thank you for posting your input. You are suggesting Scan Speak
D2905-990000. But does it have a removable faceplate? Please note
that my kefs have an unusual square plate.
However, why would I get a tweeter that goes as hi as 100Hz when the
human hearing is virtually def in those frequencies?

Thanks
Fid


You will find that very few if any Tweeters have a removable face
plate, what you will need to do is fabrecate an adapter plate to go
between the speaker cabinet and the inside of the round Tweeter face
plate.
And don't change one Tweeter change both, and modify the crossover to
suit the spec's of the new tweeters.
It really is not as simple as removeing 4 screws, and replaceing the
unit.. Well it is , if you have no idea about how they should perform.
As to the Vifa 25 dollar specials, Sure they will work, It's a bit
like sticking a VW donk in a Murcialago, [Or as TW said about the fual
injection] we know it will work, but performance is another thing
entirly .

As to the question about 100Hz rated tweeters, [ the scan speak 700000
are rated at 80 Hz ] you really have to hear the things to
understand. Again, if you want good performance, you will have to pay
for it.

Will Kef supply a PAIR of new tweeters, to suit there cabinets, and
strange as it might seem, have you tested them, disconnected from the
crossover, your speaker fault could well be a crossover componant,, It
does happen,, but i don't have any idea about the crossovers in the Kef,
it could be a complex unit, or simply just a "cap'' in the line.

bassett

[fid]

On Feb 28, 11:36 am, "Arny Krueger" wrote:
"François Yves Le Gal" wrote in
messagenews:4sabu2d0j9138b056rohqodbp0ht9ht9j2@4ax .com

On Wed, 28 Feb 2007 15:54:18 GMT, AZ Nomad
wrote:

Tweeters typically are sealed and not tuned w/ the
cabinet.
Baffle diffraction anyone?

Crossovers, anyone?

As long as the
frequency response of the replacement tweeter is
adequate, the main problem is matching levels. Get a
replacement tweeter that has the same sensativity and
the replacement will work.
Nope. Tweeters can display superficially identical
sensitivities and responses while having very different
electrical and/or acoustical properties.

Agreed. This is a KEF 107, not a FungooTek computer speaker. It is
definately worth it to do it *right*.

I can't believe that KEF doesn't have a replacement tweeter for sale at
price that is vastly less costly than the used equipment value of the
speaker.

I did contact Kef (UK & USA). Apparently they will soon have available
some replacement tweeters. I had to beg them to give me some info.
Finally the rep at Kef USA told me that it is a soft dome and the part
number is R1549X. That's only I know. No name of maker or where it is
conceived.

However. I contacted some professionals and they would at least
attempt to install a pair of ScanSpeak (even that he was more
comfortable to suggest a SEAS). No change to be made at the crossover,
thou.
When i told him that I was looking for a tweeter with the impedance of
4ohms he replied like this: "Your system is rated at 4 ohm, not the
tweeter. Systems a rated for the woofer impedance since they draw 80%
of the power from the amp. If you have access to an ohm meter, you can
check the good tweeter your self. An 8 ohm tweeter will usually have a
dc resistance of between 6-7 ohms.
A 4 ohm units would have a dcr of 3-4 ohm."

Why change tweeters? The left tweeter has less (or darker) output then
the right tweeter. It's a sign...

Best,
Fid

[Arny Krueger]

"fid" wrote in message
ps.com...

On Feb 28, 11:36 am, "Arny Krueger" wrote:

I can't believe that KEF doesn't have a replacement tweeter for sale at
price that is vastly less costly than the used equipment value of the
speaker.

I did contact Kef (UK & USA). Apparently they will soon have available
some replacement tweeters. I had to beg them to give me some info.
Finally the rep at Kef USA told me that it is a soft dome and the part
number is R1549X. That's only I know. No name of maker or where it is
conceived.

I get the impression that the origional T-33 was a Vifa-made unit. Vifa is
now a brand of DAP, whose other brands are SEAS and ScanSpeak

However. I contacted some professionals and they would at least
attempt to install a pair of ScanSpeak (even that he was more
comfortable to suggest a SEAS). No change to be made at the crossover,
thou.

This would be an experiment. What's the down side, costs?


When i told him that I was looking for a tweeter with the impedance of
4ohms he replied like this: "Your system is rated at 4 ohm, not the
tweeter. Systems a rated for the woofer impedance since they draw 80%
of the power from the amp. If you have access to an ohm meter, you can
check the good tweeter your self. An 8 ohm tweeter will usually have a
dc resistance of between 6-7 ohms.

All true statements, but not really responsive to your question. In the US
we speak of "Snow Jobs".


A 4 ohm units would have a dcr of 3-4 ohm."

Also true, but relating how to the price of tea at the supermarket?

Why change tweeters? The left tweeter has less (or darker) output then
the right tweeter. It's a sign...

Presumably you've physically exchanged the speakers in your listening (left
& right swap) and the problem stayed with the speaker.

[John Stone]

On 3/1/07 6:36 AM, in article ,
"Arny Krueger" wrote:

I get the impression that the origional T-33 was a Vifa-made unit. Vifa is
now a brand of DAP, whose other brands are SEAS and ScanSpeak

KEF never had drive units made by Vifa. The T-33 was made by KEF in Britain.
Vifa is gone. The brand has been rolled into Peerless, and the old Vifa
products, few of which are still available, are sold under the "Peerless
V-line" I don't have any idea what DAP is, but the umbrella company that
previously owned Vifa, ScanSpeak, and Peerless was called DST. They too are
gone, having been purchased by Tymphany, which is an American company based
in Silicon Valley. The same venture company that holds Tymphany also owns
Klipsch and Jamo. SEAS has always been completely independent of the others
and remains so today. It is employee owned.

[Arny Krueger]

"John Stone" wrote in message
...

On 3/1/07 6:36 AM, in article
,
"Arny Krueger" wrote:

I get the impression that the origional T-33 was a Vifa-made unit. Vifa
is
now a brand of DAP, whose other brands are SEAS and ScanSpeak

KEF never had drive units made by Vifa.

So much for the web page that suggested it to me. Hmm which of the many I
looked at yesterday was that?

The T-33 was made by KEF in Britain.

Vifa is gone. The brand has been rolled into Peerless, and the old Vifa
products, few of which are still available, are sold under the "Peerless
V-line" I don't have any idea what DAP is, but the umbrella company that
previously owned Vifa, ScanSpeak, and Peerless was called DST.

DAP was corruption of DST, you know Danish-something. In this case my
coffee-starved memory coughed out "Danish Audio Products", but that's wrong.

They too are
gone, having been purchased by Tymphany, which is an American company
based
in Silicon Valley.

Is that Ken Kantor's place?

The same venture company that holds Tymphany also owns
Klipsch and Jamo. SEAS has always been completely independent of the
others
and remains so today. It is employee owned.

Thanks for the correction, John. If anybody would know this stuff, it would
be you. Are you doing any work for any of the above?

[John Stone]

On 3/1/07 7:40 AM, in article ,
"Arny Krueger" wrote:


"John Stone" wrote in message
...

They too are
gone, having been purchased by Tymphany, which is an American company
based
in Silicon Valley.

Is that Ken Kantor's place?

Yes

The same venture company that holds Tymphany also owns
Klipsch and Jamo. SEAS has always been completely independent of the
others
and remains so today. It is employee owned.

Thanks for the correction, John. If anybody would know this stuff, it would
be you. Are you doing any work for any of the above?

SEAS

[fid]

You will find that very few if any Tweeters have a removable face
plate, what you will need to do is fabrecate an adapter plate to go
between the speaker cabinet and the inside of the round Tweeter face
plate.

They ( the professionals) will adapt, somehow, the new tweeters to the
speakers enclosure.

And don't change one Tweeter change both, and modify the crossover to
suit the spec's of the new tweeters.

I have no idea how to change the crossover. I will not touch that.


As to the question about 100Hz rated tweeters, [ the scan speak 700000
are rated at 80 Hz ] you really have to hear the things to
understand. Again, if you want good performance, you will have to pay
for it.

I don't mind spending more for a more desirable performance.

Will Kef supply a PAIR of new tweeters, to suit there cabinets, and
strange as it might seem, have you tested them, disconnected from the
crossover, your speaker fault could well be a crossover componant,, It
does happen,, but i don't have any idea about the crossovers in the Kef,
it could be a complex unit, or simply just a "cap'' in the line.

What attracts me from choosing Kef's tweeters as replacement is that
it would be more likely to succeed in this replacement. But I know
virtually nothing about their new tweeters.

It is obvious that I am a novice here, but please excuse me if I
insist: if the tweeter has the appropriate impedance and sensitivity,
and it has the proper frequency range suitable for the cut-point, why
would I need to modify the crossover network?

I like the Kef 107 very much, but I always felt that the tweeters
could have been somewhat different.
So I am looking forward to replace them. But I what to do this very
carefully. For that I appreciated your inputs.

[Kalman Rubinson]

On 1 Mar 2007 19:41:15 -0800, "fid" wrote:

It is obvious that I am a novice here, but please excuse me if I
insist: if the tweeter has the appropriate impedance and sensitivity,
and it has the proper frequency range suitable for the cut-point, why
would I need to modify the crossover network?

Because each of those numbers represents a snapshot of a continuously
varying parameter. Impedance at a single frequency does not
characterise the impedance across the spectrum adequately for
crossover design. Similarly, senstivity varies with frequency and the
crossover is designed to account for it. Picking by those single
numbers is insufficient and barely more useful than picking by color.

I recommend you accept KEF's recommendation.

Kal

[ScottW]

"Kalman Rubinson" wrote in message
...
On 1 Mar 2007 19:41:15 -0800, "fid" wrote:

It is obvious that I am a novice here, but please excuse me if I
insist: if the tweeter has the appropriate impedance and sensitivity,
and it has the proper frequency range suitable for the cut-point, why
would I need to modify the crossover network?

Because each of those numbers represents a snapshot of a continuously
varying parameter. Impedance at a single frequency does not
characterise the impedance across the spectrum adequately for
crossover design.

Actually....the term impedance implies a complex
model that will vary response with frequency.

I think you're confusing nominal impedance.

If the complex impedance of the drivers are the same,
then the response of the crossover will not be adversely
affected. Then if the sensitivity of the drivers are the same,
the basic response will be very similar.
Only significant variable left is dispersion patterns and baffle
interaction.

I would agree that most driver specs don't make it easy to
determine the true impedance of the driver.

Similarly, senstivity varies with frequency and the
crossover is designed to account for it.

Freq. sensitivity plots are readily available though.
For example
http://www.madisound.com/pdf/seas/e006.pdf

Picking by those single
numbers is insufficient and barely more useful than picking by color.

I recommend you accept KEF's recommendation.

How much is it?

ScottW

[fid]

On Mar 3, 1:35 pm, "ScottW" wrote:
"Kalman Rubinson" wrote in message

...

On 1 Mar 2007 19:41:15 -0800, "fid" wrote:

It is obvious that I am a novice here, but please excuse me if I
insist: if the tweeter has the appropriate impedance and sensitivity,
and it has the proper frequency range suitable for the cut-point, why
would I need to modify the crossover network?

Because each of those numbers represents a snapshot of a continuously
varying parameter. Impedance at a single frequency does not
characterise the impedance across the spectrum adequately for
crossover design.

Actually....the term impedance implies a complex
model that will vary response with frequency.

I think you're confusing nominal impedance.

If the complex impedance of the drivers are the same,
then the response of the crossover will not be adversely
affected. Then if the sensitivity of the drivers are the same,
the basic response will be very similar.
Only significant variable left is dispersion patterns and baffle
interaction.

I would agree that most driver specs don't make it easy to
determine the true impedance of the driver.

Similarly, senstivity varies with frequency and the
crossover is designed to account for it.

Freq. sensitivity plots are readily available though.
For examplehttp://www.madisound.com/pdf/seas/e006.pdf

Picking by those single
numbers is insufficient and barely more useful than picking by color.

I recommend you accept KEF's recommendation.

How much is it?

ScottW

ScottW

Kef replacements are selling for $160.

If you tell me to stop thinking about those ScanSpeaks Revelators,
then I will definitely choose the Kef's. But if the ScanSpeak will
produce an acceptable sound without scratching noises.. why not, I
would think!

[ScottW]

"fid" wrote in message
ups.com...
On Mar 3, 1:35 pm, "ScottW" wrote:
"Kalman Rubinson" wrote in message

...

On 1 Mar 2007 19:41:15 -0800, "fid" wrote:

It is obvious that I am a novice here, but please excuse me if I
insist: if the tweeter has the appropriate impedance and sensitivity,
and it has the proper frequency range suitable for the cut-point, why
would I need to modify the crossover network?

Because each of those numbers represents a snapshot of a continuously
varying parameter. Impedance at a single frequency does not
characterise the impedance across the spectrum adequately for
crossover design.

Actually....the term impedance implies a complex
model that will vary response with frequency.

I think you're confusing nominal impedance.

If the complex impedance of the drivers are the same,
then the response of the crossover will not be adversely
affected. Then if the sensitivity of the drivers are the same,
the basic response will be very similar.
Only significant variable left is dispersion patterns and baffle
interaction.

I would agree that most driver specs don't make it easy to
determine the true impedance of the driver.

Similarly, senstivity varies with frequency and the
crossover is designed to account for it.

Freq. sensitivity plots are readily available though.
For examplehttp://www.madisound.com/pdf/seas/e006.pdf

Picking by those single
numbers is insufficient and barely more useful than picking by color.

I recommend you accept KEF's recommendation.

How much is it?

ScottW

ScottW

Kef replacements are selling for $160.

Is that each or a pair?


If you tell me to stop thinking about those ScanSpeaks Revelators,
then I will definitely choose the Kef's. But if the ScanSpeak will
produce an acceptable sound without scratching noises.. why not, I
would think!

I think substituting drivers is just an absolute crapshoot
as the information you would need to identify a
well matched replacement isn't available.

However, the was a report from a guy that says the
Vifa MG27 is an easy fit and sounded good.
Thats a $44 crapshoot...and Madisound might be willing
to offer a return if you don't solder leads for a nominal restocking
fee. Point is...there is a risk vs reward decision and only you
can evaluate how much risk you're willing to assume.

ScottW

[Kalman Rubinson]

On Sat, 3 Mar 2007 10:35:14 -0800, "ScottW"
wrote:

Actually....the term impedance implies a complex
model that will vary response with frequency.

I think you're confusing nominal impedance.

Not confusing the terms but, unfortunately, I didn't use the correct
ones explicitely. As you state, the nominal impedance is almost
always offered but the complex impedance graph less commonly.

I am in agreement with you that swapping drivers is a crap-shoot
unless one is willing and able to undertake a potential redesign.

Kal

[Trevor Wilson]

"Kalman Rubinson" wrote in message
...
On Sat, 3 Mar 2007 10:35:14 -0800, "ScottW"
wrote:

Actually....the term impedance implies a complex
model that will vary response with frequency.

I think you're confusing nominal impedance.

Not confusing the terms but, unfortunately, I didn't use the correct
ones explicitely.

**You explained it perfectly. Scotty is an idiot.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[Trevor Wilson]

"fid" wrote in message
ups.com...
On Mar 3, 1:35 pm, "ScottW" wrote:
"Kalman Rubinson" wrote in message

...

On 1 Mar 2007 19:41:15 -0800, "fid" wrote:

It is obvious that I am a novice here, but please excuse me if I
insist: if the tweeter has the appropriate impedance and sensitivity,
and it has the proper frequency range suitable for the cut-point, why
would I need to modify the crossover network?

Because each of those numbers represents a snapshot of a continuously
varying parameter. Impedance at a single frequency does not
characterise the impedance across the spectrum adequately for
crossover design.

Actually....the term impedance implies a complex
model that will vary response with frequency.

I think you're confusing nominal impedance.

If the complex impedance of the drivers are the same,
then the response of the crossover will not be adversely
affected. Then if the sensitivity of the drivers are the same,
the basic response will be very similar.
Only significant variable left is dispersion patterns and baffle
interaction.

I would agree that most driver specs don't make it easy to
determine the true impedance of the driver.

Similarly, senstivity varies with frequency and the
crossover is designed to account for it.

Freq. sensitivity plots are readily available though.
For examplehttp://www.madisound.com/pdf/seas/e006.pdf

Picking by those single
numbers is insufficient and barely more useful than picking by color.

I recommend you accept KEF's recommendation.

How much is it?

ScottW

ScottW

Kef replacements are selling for $160.

If you tell me to stop thinking about those ScanSpeaks Revelators,
then I will definitely choose the Kef's. But if the ScanSpeak will
produce an acceptable sound without scratching noises.. why not, I
would think!

**Have you read ANY of the posts from those who actually know? Or are you
being deliberately obtuse?


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[bassett]

"Kalman Rubinson" wrote in message
...
On Sat, 3 Mar 2007 10:35:14 -0800, "ScottW"
wrote:

Actually....the term impedance implies a complex
model that will vary response with frequency.

I think you're confusing nominal impedance.

Not confusing the terms but, unfortunately, I didn't use the correct
ones explicitely. As you state, the nominal impedance is almost
always offered but the complex impedance graph less commonly.

I am in agreement with you that swapping drivers is a crap-shoot
unless one is willing and able to undertake a potential redesign.

Kal


It comes down to how much work your prepaired for, if you just want
the same result, by all means go for the KEF replacements, They
should be the same values as the one's there replacing, and should not
require any work on the crossovers. Plus, they will fit.

If you deside on the Vifa's Scan Speak, or whatever, for best results
you will need to play with the "cap' values
in the crossover, to obtain a balanced result,
As our friend states above, it's a "crap-shoot" you can buy the worlds
best, but get the crossover values wrong, and they will sound like crap,
and the cheapest tweeters around with good matching crossover componants
will sound like the "ducks nuts" It's all about trial and error


bassett

[Arny Krueger]

"bassett" wrote in message

"Kalman Rubinson" wrote in message
...
On Sat, 3 Mar 2007 10:35:14 -0800, "ScottW"
wrote:

Actually....the term impedance implies a complex
model that will vary response with frequency.

I think you're confusing nominal impedance.

Not confusing the terms but, unfortunately, I didn't use
the correct ones explicitely. As you state, the nominal
impedance is almost always offered but the complex
impedance graph less commonly. I am in agreement with you that swapping
drivers is a
crap-shoot unless one is willing and able to undertake a
potential redesign. Kal


It comes down to how much work your prepaired for, if you just want
the same result, by all means go for
the KEF replacements, They should be the same values as the one's
there replacing, and should not require any work on the crossovers.
Plus, they will fit.
If you deside on the Vifa's Scan Speak, or whatever, for best results
you will need to play with the "cap' values in the crossover, to obtain
a balanced result,
As our friend states above, it's a "crap-shoot" you
can buy the worlds best, but get the crossover values
wrong, and they will sound like crap, and the cheapest
tweeters around with good matching crossover
componants will sound like the "ducks nuts" It's
all about trial and error

It's really a crap shoot, because it is impossible to merely diddle the
crossover and get a good balance with a tweeter that is not efficient enough
for the rest of the system.

[fid]

An update... I installed new tweeters purchased from Kef (R1549).
Contrary to what they told me, these tweeters are far from being
compatible. The problem is that these tweeters are too loud making the
sound harsh. I am disappointed and I am planning to return them.

[mameluk]

This article on www.audiobanter.com is bookmark worthy in my opinion. It's worth saving for future reference. It's fascinating reading with many valid points for contemplation. I have to concur on almost every point made within this article.