On 07/04/2011 14:34, No Win No Fee wrote:
Keith G wrote:

"No Win No Fee" wrote in message
...
Keith G wrote:




But will it matter at the end of the day? Just putting new drivers
into (presumably) old 3-way speakers is going to alter things even
if only slightly and it will only take 20 minutes to absorb the
changes.



Yes it matters.
There is the Thiele Small parameters of the enclosure, the cross over
network and how many drivers in each enclosure and how they are
configured to seamlessly intergrate etc. Then there is the "load" that
the driver represents to the amplifier. And the sensitivity of each
driver and the enclosure as a whole etc. The wrong mid-range driver
will result in either a mid-range suck out if too insensitive, or an
overall drained and stressed sound if too awkward a load. Conversely
an over sensitive new drive could result in dominant mid-range and a
percieved premature roll off in HF and LF.
Fitting a drive just because it fits the baffle cut-out is not a good
idea.


Yes, yes. yes! Agree with all you say, but if you contact a 'certain
well-known supplier' and just describe the speakers without any brand
names or spec. that supplier will almost certainly be able to
recommend and supply a 'safe bet' driver.


That is impossible. And if such a dealer were to make such a claim
that they could supply a "safe bet" based on a description then that
is a dealer who should be revealed for ridicule. Name him?

This is a relatively easy load and high sensitivity drive that fits
the 80 mm requirement of the subject of thread:
http://www.adamhall.com/en/Faital_PR...FP5FE120A.html


This is an awkward load, low effienciency/low sensitivity drive that
would also fit the baffle cut out:
http://snipurl.com/27r2as

Both of above randomly plucked examples have very different specs
and demands, and cross-over and enclosure requirements.

This is a straightforward 3 way floorstander of medium sensitivity
and an overall nominal 6ohm load:
http://www.ultraaudio.com/features/p...01_spendor.jpg
The midrange drive is an 80mm as subject of thread.
If the mid-range drivers were to be replaced with either of the two
very different examples above, the results would be serious mismatch
and with the awkward load drive - possible hardware disaster!

You can fit the high sensitivity driver mentioned above, measure the
response,
and attenuate it with 2 resistors (with the BBC dip if you like :-) ).
As any multi-way speaker crosses over well above the fundamental resonance
of the midrange unit, it's really only the impedance and sensitivity
that matters.

--
Eiron.

"Eiron" wrote in message
...
On 07/04/2011 14:34, No Win No Fee wrote:
Keith G wrote:

"No Win No Fee" wrote in message
...
Keith G wrote:




But will it matter at the end of the day? Just putting new drivers
into (presumably) old 3-way speakers is going to alter things even if
only slightly and it will only take 20 minutes to absorb the changes.



Yes it matters.
There is the Thiele Small parameters of the enclosure, the cross over
network and how many drivers in each enclosure and how they are
configured to seamlessly intergrate etc. Then there is the "load" that
the driver represents to the amplifier. And the sensitivity of each
driver and the enclosure as a whole etc. The wrong mid-range driver
will result in either a mid-range suck out if too insensitive, or an
overall drained and stressed sound if too awkward a load. Conversely
an over sensitive new drive could result in dominant mid-range and a
percieved premature roll off in HF and LF.
Fitting a drive just because it fits the baffle cut-out is not a good
idea.


Yes, yes. yes! Agree with all you say, but if you contact a 'certain
well-known supplier' and just describe the speakers without any brand
names or spec. that supplier will almost certainly be able to recommend
and supply a 'safe bet' driver.


That is impossible. And if such a dealer were to make such a claim
that they could supply a "safe bet" based on a description then that
is a dealer who should be revealed for ridicule. Name him?

This is a relatively easy load and high sensitivity drive that fits
the 80 mm requirement of the subject of thread:
http://www.adamhall.com/en/Faital_PR...FP5FE120A.html
This is an awkward load, low effienciency/low sensitivity drive that
would also fit the baffle cut out:
http://snipurl.com/27r2as

Both of above randomly plucked examples have very different specs
and demands, and cross-over and enclosure requirements.

This is a straightforward 3 way floorstander of medium sensitivity
and an overall nominal 6ohm load:
http://www.ultraaudio.com/features/p...01_spendor.jpg
The midrange drive is an 80mm as subject of thread.
If the mid-range drivers were to be replaced with either of the two
very different examples above, the results would be serious mismatch
and with the awkward load drive - possible hardware disaster!

You can fit the high sensitivity driver mentioned above, measure the
response,
and attenuate it with 2 resistors (with the BBC dip if you like :-) ).
As any multi-way speaker crosses over well above the fundamental resonance
of the midrange unit, it's really only the impedance and sensitivity that
matters.


Yes, notice the OP claimed the mid-range units needing replaced was an
unlikely (I would have thought) 16 Ohm!

In article ,
Keith G wrote:
Yes, notice the OP claimed the mid-range units needing replaced was an
unlikely (I would have thought) 16 Ohm!

You think wrong.

--
*If you remember the '60s, you weren't really there

Dave Plowman London SW
To e-mail, change noise into sound.