Cartridge response - pink noise test
 

Don Pearce wrote:
Apropos of some stuff we were doing a while ago, here is the pink
noise track from th HFN-RR test disk played on my system, which is:

Systemdek IV
SME 3009ii arm
AT-OC9 microline cartridge

http://81.174.169.10/odds/dspkr/atoc9.gif

It shows an essentially flat response from about 12Hz, with a slight
lift at 10kHz, then returning to the proper level above that. The
recording is made at 96kHz sampling, and it is clear that the test
record cuts off sharply at 20kHz. The cartridge claims to go to 60kHz
(ahem!)

I've offset the levels of the left and right tracks slightly so they
are more visible.

d


Very nice, it does seem to show a flat response down to what I would
have guessed was arm/cartridge resonance frequencies, wich is rather
impressive.

--
Nick

Cartridge response - pink noise test
 

On Wed, 18 Oct 2006 21:34:07 +0100, Nick Gorham
wrote:

Don Pearce wrote:
Apropos of some stuff we were doing a while ago, here is the pink
noise track from th HFN-RR test disk played on my system, which is:

Systemdek IV
SME 3009ii arm
AT-OC9 microline cartridge

http://81.174.169.10/odds/dspkr/atoc9.gif

It shows an essentially flat response from about 12Hz, with a slight
lift at 10kHz, then returning to the proper level above that. The
recording is made at 96kHz sampling, and it is clear that the test
record cuts off sharply at 20kHz. The cartridge claims to go to 60kHz
(ahem!)

I've offset the levels of the left and right tracks slightly so they
are more visible.

d


Very nice, it does seem to show a flat response down to what I would
have guessed was arm/cartridge resonance frequencies, wich is rather
impressive.

Yes there is another test track for resonance, which comes out at
11Hz, which is a pretty much ideal compromise.

What this was all about was the top end response of MC cartridges,
which I think (from theory) tends to be better controlled than in MM
types. I'm hoping that somebody with a MM cart has the wherewithall to
replicate this so we can compare.

d

--
Pearce Consulting
http://www.pearce.uk.com

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

Cartridge response - pink noise test
 

In message , Don Pearce
writes
On Wed, 18 Oct 2006 21:10:55 +0100, "Keith G"
wrote:

snip good explanation

Why use pink noise instead of white noise, which would have looked
flat? If they had tried that on vinyl the high frequencies would have
melted the cutter head. They have to cool them with liquid helium as
it is.

Ahem! It's just A grade helium gas, not liquid.
--
Kevin Seal
F800ST
{kevin at the hyphen seal hyphen house dot freeserve dot co dot uk}

Cartridge response - pink noise test
 

On Wed, 18 Oct 2006 22:38:41 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Wed, 18 Oct 2006 21:10:55 +0100, "Keith G"
wrote:

snip good explanation

Why use pink noise instead of white noise, which would have looked
flat? If they had tried that on vinyl the high frequencies would have
melted the cutter head. They have to cool them with liquid helium as
it is.

Ahem! It's just A grade helium gas, not liquid.

I thought helium gas was only used on Pinky and Perky records. But
there we go, gas it is - my memory is playing games with me.

d

--
Pearce Consulting
http://www.pearce.uk.com

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

Cartridge response - pink noise test
 

In message , Don Pearce
writes
On Wed, 18 Oct 2006 22:38:41 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Wed, 18 Oct 2006 21:10:55 +0100, "Keith G"
wrote:

snip good explanation

Why use pink noise instead of white noise, which would have looked
flat? If they had tried that on vinyl the high frequencies would have
melted the cutter head. They have to cool them with liquid helium as
it is.

Ahem! It's just A grade helium gas, not liquid.

I thought helium gas was only used on Pinky and Perky records. But
there we go, gas it is - my memory is playing games with me.

Me, waste the expensive cutting helium, to talk like a choir boy again?
Never! ;)
--
Kevin Seal
F800ST
{kevin at the hyphen seal hyphen house dot freeserve dot co dot uk}

Cartridge response - pink noise test
 

"Don Pearce" wrote in message
...
On Wed, 18 Oct 2006 21:34:07 +0100, Nick Gorham
wrote:

Don Pearce wrote:
Apropos of some stuff we were doing a while ago, here is the pink
noise track from th HFN-RR test disk played on my system, which is:

Systemdek IV
SME 3009ii arm
AT-OC9 microline cartridge

http://81.174.169.10/odds/dspkr/atoc9.gif

It shows an essentially flat response from about 12Hz, with a slight
lift at 10kHz, then returning to the proper level above that. The
recording is made at 96kHz sampling, and it is clear that the test
record cuts off sharply at 20kHz. The cartridge claims to go to 60kHz
(ahem!)

I've offset the levels of the left and right tracks slightly so they
are more visible.

d


Very nice, it does seem to show a flat response down to what I would
have guessed was arm/cartridge resonance frequencies, wich is rather
impressive.

Yes there is another test track for resonance, which comes out at
11Hz, which is a pretty much ideal compromise.

What this was all about was the top end response of MC cartridges,
which I think (from theory) tends to be better controlled than in MM
types. I'm hoping that somebody with a MM cart has the wherewithall to
replicate this so we can compare.


What do you want done?

I've got a number of MC and MM carts on headshells so can swap fairly
quickly - as well as the HFS69 and HFS75 test records with various bands on
them including pink noise or white noise with 'constant energy per Hz'....??
(Would that give you a *level* flat line?)

I could send you a set of wavs to mess with if you let me know what you
need...??

Cartridge response - pink noise test
 

On Wed, 18 Oct 2006 23:57:09 +0100, "Keith G"
wrote:


"Don Pearce" wrote in message
...
On Wed, 18 Oct 2006 21:34:07 +0100, Nick Gorham
wrote:

Don Pearce wrote:
Apropos of some stuff we were doing a while ago, here is the pink
noise track from th HFN-RR test disk played on my system, which is:

Systemdek IV
SME 3009ii arm
AT-OC9 microline cartridge

http://81.174.169.10/odds/dspkr/atoc9.gif

It shows an essentially flat response from about 12Hz, with a slight
lift at 10kHz, then returning to the proper level above that. The
recording is made at 96kHz sampling, and it is clear that the test
record cuts off sharply at 20kHz. The cartridge claims to go to 60kHz
(ahem!)

I've offset the levels of the left and right tracks slightly so they
are more visible.

d


Very nice, it does seem to show a flat response down to what I would
have guessed was arm/cartridge resonance frequencies, wich is rather
impressive.

Yes there is another test track for resonance, which comes out at
11Hz, which is a pretty much ideal compromise.

What this was all about was the top end response of MC cartridges,
which I think (from theory) tends to be better controlled than in MM
types. I'm hoping that somebody with a MM cart has the wherewithall to
replicate this so we can compare.


What do you want done?

I've got a number of MC and MM carts on headshells so can swap fairly
quickly - as well as the HFS69 and HFS75 test records with various bands on
them including pink noise or white noise with 'constant energy per Hz'....??
(Would that give you a *level* flat line?)


You've got it!

I could send you a set of wavs to mess with if you let me know what you
need...??




a wav of the pink noise would be the thing. Only need about ten
seconds of it, so no need to make it huge. The V15 would be a good
place to start - it being a kind of reference to a lot of people..

d

--
Pearce Consulting
http://www.pearce.uk.com

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

Cartridge response - pink noise test
 

On Wed, 18 Oct 2006 23:57:09 +0100, "Keith G"
wrote:


"Don Pearce" wrote in message
...
On Wed, 18 Oct 2006 21:34:07 +0100, Nick Gorham
wrote:

Don Pearce wrote:
Apropos of some stuff we were doing a while ago, here is the pink
noise track from th HFN-RR test disk played on my system, which is:

Systemdek IV
SME 3009ii arm
AT-OC9 microline cartridge

http://81.174.169.10/odds/dspkr/atoc9.gif

It shows an essentially flat response from about 12Hz, with a slight
lift at 10kHz, then returning to the proper level above that. The
recording is made at 96kHz sampling, and it is clear that the test
record cuts off sharply at 20kHz. The cartridge claims to go to 60kHz
(ahem!)

I've offset the levels of the left and right tracks slightly so they
are more visible.

d


Very nice, it does seem to show a flat response down to what I would
have guessed was arm/cartridge resonance frequencies, wich is rather
impressive.

Yes there is another test track for resonance, which comes out at
11Hz, which is a pretty much ideal compromise.

What this was all about was the top end response of MC cartridges,
which I think (from theory) tends to be better controlled than in MM
types. I'm hoping that somebody with a MM cart has the wherewithall to
replicate this so we can compare.


What do you want done?

I've got a number of MC and MM carts on headshells so can swap fairly
quickly - as well as the HFS69 and HFS75 test records with various bands on
them including pink noise or white noise with 'constant energy per Hz'....??
(Would that give you a *level* flat line?)

I could send you a set of wavs to mess with if you let me know what you
need...??



Forgot to add - for this test it is vital that there is no clipping -
that would screw the measurement utterly.

d

--
Pearce Consulting
http://www.pearce.uk.com

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

Cartridge response - pink noise test
 

"Don Pearce" wrote


Forgot to add - for this test it is vital that there is no clipping -
that would screw the measurement utterly.


The clip is on its way to you direct.

Cartridge response - pink noise test
 

On Thu, 19 Oct 2006 00:36:37 +0100, "Keith G"
wrote:


"Don Pearce" wrote


Forgot to add - for this test it is vital that there is no clipping -
that would screw the measurement utterly.


The clip is on its way to you direct.



Courtesy of Keith we now have a pink noise track of a Shure V15/5. It
has a smooth if slightly depressed top end, rather wavy midrange and
rolled off bass. Interesting! Again I have added the "nominally flat"
line for comparison - I've tried to put it in a sort of average
position.

http://81.174.169.10/odds/dspkr/v15pink.gif

d

--
Pearce Consulting
http://www.pearce.uk.com

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