Good morning experts ;-)

I've been going through my HFN test record. Most of it makes sense but I
don't understand my pink noise results. They show an approximate 10 dB /
decade tilt, which is what I would expect from pink noise. For example,
here's a frequency analysis of a 'perfect' pink noise sample generated
by Audacity.

http://www.nu-ware.com/Misc/Screensh...nk%20Noise.png

Here is the result of the HFN pink noise test using my M55E cartridge.

http://www.nu-ware.com/Misc/Screensh...nk%20Noise.png

However, when I look at test results around the web I see essentially
flat curves from pink noise tests. Like this:

http://www.tnt-audio.com/sorgenti/shure_m97xe_e.html

So, what am I missing?

On Wed, 11 Mar 2015 10:39:25 +0000, Sumatriptan
wrote:

Good morning experts ;-)

I've been going through my HFN test record. Most of it makes sense but I
don't understand my pink noise results. They show an approximate 10 dB /
decade tilt, which is what I would expect from pink noise. For example,
here's a frequency analysis of a 'perfect' pink noise sample generated
by Audacity.

http://www.nu-ware.com/Misc/Screensh...nk%20Noise.png

Here is the result of the HFN pink noise test using my M55E cartridge.

http://www.nu-ware.com/Misc/Screensh...nk%20Noise.png

However, when I look at test results around the web I see essentially
flat curves from pink noise tests. Like this:

http://www.tnt-audio.com/sorgenti/shure_m97xe_e.html

So, what am I missing?



Those last curves have been "corrected" to look flat. Essentially what
they are showing is the difference between the perfect pink noise and
that recovered from the record.

Yours is showing signs of being a bit saggy at the top and bottom of
the band. Could do particularly with a touch of bass lift.

d

On 11/03/2015 11:05, Don Pearce wrote:


Those last curves have been "corrected" to look flat. Essentially what
they are showing is the difference between the perfect pink noise and
that recovered from the record.

Yours is showing signs of being a bit saggy at the top and bottom of
the band. Could do particularly with a touch of bass lift.


OK, I've put up a revised curve that I 'corrected' with an eq with slope
opposite the the 10 dB/Decade slope of 1/f pink noise.

He
http://www.nu-ware.com/Misc/Screensh...0Flattened.png

As well as the 'correction' I added 330 pF of capacitive loading since
the only other capacitance was the 100 pF of the preamp input and Shure
cartridges work best with 400-500 pF, says the spec. Recall, I have
removed the phono leads and installed the preamp in the turntable near
the tonearm.

I know that this result assumes that the pink noise from the record is
perfect, which is most likely not so.

Whatever, the output sounds excellent to me and my first tests with
LP--CD transfer went very well.

On Thu, 12 Mar 2015 13:35:47 +0000, Sumatriptan
wrote:

On 11/03/2015 11:05, Don Pearce wrote:


Those last curves have been "corrected" to look flat. Essentially what
they are showing is the difference between the perfect pink noise and
that recovered from the record.

Yours is showing signs of being a bit saggy at the top and bottom of
the band. Could do particularly with a touch of bass lift.


OK, I've put up a revised curve that I 'corrected' with an eq with slope
opposite the the 10 dB/Decade slope of 1/f pink noise.

He
http://www.nu-ware.com/Misc/Screensh...0Flattened.png

As well as the 'correction' I added 330 pF of capacitive loading since
the only other capacitance was the 100 pF of the preamp input and Shure
cartridges work best with 400-500 pF, says the spec. Recall, I have
removed the phono leads and installed the preamp in the turntable near
the tonearm.

I know that this result assumes that the pink noise from the record is
perfect, which is most likely not so.

Whatever, the output sounds excellent to me and my first tests with
LP--CD transfer went very well.

The bottom end looks pretty good.The 4dB drop from 2kHz 9kHz would be
the sort of adjustment a mixing engineer would make to remove some
"air" from a recording. Equalise that back up to flat, and suddenly
sounds played from this cartridge will gain a lot of sparkle.

d

On 12/03/2015 13:53, Don Pearce wrote:


The bottom end looks pretty good.The 4dB drop from 2kHz 9kHz would be
the sort of adjustment a mixing engineer would make to remove some
"air" from a recording. Equalise that back up to flat, and suddenly
sounds played from this cartridge will gain a lot of sparkle.


I tried some gentle eq over that range. Yes, the brightness of the sound
is enhanced but so are surface hiss and clicks of course.

Obviously, there are compromises to be made depending on the state and
content of each record. How much eq if any, manual or auto declick, to
denoise or not, how much time I want to spend etc. etc.

Sumatriptan wrote:


I tried some gentle eq over that range. Yes, the brightness of the sound
is enhanced but so are surface hiss and clicks of course.

Obviously, there are compromises to be made depending on the state and
content of each record. How much eq if any, manual or auto declick, to
denoise or not, how much time I want to spend etc. etc.


**Sure thing, polishing turds is a very tedious business ...




.... Phil

Sumatriptan wrote:


I've been going through my HFN test record. Most of it makes sense but I
don't understand my pink noise results. They show an approximate 10 dB /
decade tilt, which is what I would expect from pink noise. For example,
here's a frequency analysis of a 'perfect' pink noise sample generated
by Audacity.

http://www.nu-ware.com/Misc/Screensh...nk%20Noise.png

Here is the result of the HFN pink noise test using my M55E cartridge.

http://www.nu-ware.com/Misc/Screensh...nk%20Noise.png

However, when I look at test results around the web I see essentially
flat curves from pink noise tests. Like this:

http://www.tnt-audio.com/sorgenti/shure_m97xe_e.html

So, what am I missing?


** Pink noise has equal amounts of energy in each octave or fraction thereof.

Spectrum analysis software ( like FFT ) has to be set to read the signal in terms of octaves rather than some fixed bandwidth in Hz in order to see a horizontal graph.


.... Phil

In article ,
Sumatriptan wrote:
Good morning experts ;-)

I've been going through my HFN test record. Most of it makes sense but I
don't understand my pink noise results. They show an approximate 10 dB /
decade tilt, which is what I would expect from pink noise. For example,
here's a frequency analysis of a 'perfect' pink noise sample generated
by Audacity.

http://www.nu-ware.com/Misc/Screensh...nk%20Noise.png

Here is the result of the HFN pink noise test using my M55E cartridge.

http://www.nu-ware.com/Misc/Screensh...nk%20Noise.png

However, when I look at test results around the web I see essentially
flat curves from pink noise tests. Like this:

http://www.tnt-audio.com/sorgenti/shure_m97xe_e.html

So, what am I missing?

I'd say it's likely impossible to record perfect pink noise to vinyl.

The peaks you're seeing above 10kHz are likely down to the capacitance of
the connecting leads. If you try a different type, you'll likely see a
different result. Not quite sure of the theory behind this, but it's what
I've experienced with variable reluctance cartridges. Perhaps an expert
would explain it?

--
*It's o.k. to laugh during sexŒ.Œ.just don't point!

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

On Wed, 11 Mar 2015 11:21:54 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
Sumatriptan wrote:
Good morning experts ;-)

I've been going through my HFN test record. Most of it makes sense but I
don't understand my pink noise results. They show an approximate 10 dB /
decade tilt, which is what I would expect from pink noise. For example,
here's a frequency analysis of a 'perfect' pink noise sample generated
by Audacity.

http://www.nu-ware.com/Misc/Screensh...nk%20Noise.png

Here is the result of the HFN pink noise test using my M55E cartridge.

http://www.nu-ware.com/Misc/Screensh...nk%20Noise.png

However, when I look at test results around the web I see essentially
flat curves from pink noise tests. Like this:

http://www.tnt-audio.com/sorgenti/shure_m97xe_e.html

So, what am I missing?

I'd say it's likely impossible to record perfect pink noise to vinyl.

The peaks you're seeing above 10kHz are likely down to the capacitance of
the connecting leads. If you try a different type, you'll likely see a
different result. Not quite sure of the theory behind this, but it's what
I've experienced with variable reluctance cartridges. Perhaps an expert
would explain it?

Hadn't thought about the vinyl limitations. The bottom end rolloff
probably happened during mastering to stop the cutter ripping the
vinyl in two.

The top end is certainly some sort of resonance - whether mechanical
in the cartridge, or as you say electrical between the cartridge
inductance and the cable capacitance.

d

On Wed, 11 Mar 2015 11:39:29 GMT, (Don Pearce) wrote:

On Wed, 11 Mar 2015 11:21:54 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
Sumatriptan wrote:
Good morning experts ;-)

I've been going through my HFN test record. Most of it makes sense but I
don't understand my pink noise results. They show an approximate 10 dB /
decade tilt, which is what I would expect from pink noise. For example,
here's a frequency analysis of a 'perfect' pink noise sample generated
by Audacity.

http://www.nu-ware.com/Misc/Screensh...nk%20Noise.png

Here is the result of the HFN pink noise test using my M55E cartridge.

http://www.nu-ware.com/Misc/Screensh...nk%20Noise.png

However, when I look at test results around the web I see essentially
flat curves from pink noise tests. Like this:

http://www.tnt-audio.com/sorgenti/shure_m97xe_e.html

So, what am I missing?

I'd say it's likely impossible to record perfect pink noise to vinyl.

The peaks you're seeing above 10kHz are likely down to the capacitance of
the connecting leads. If you try a different type, you'll likely see a
different result. Not quite sure of the theory behind this, but it's what
I've experienced with variable reluctance cartridges. Perhaps an expert
would explain it?

Hadn't thought about the vinyl limitations. The bottom end rolloff
probably happened during mastering to stop the cutter ripping the
vinyl in two.

The top end is certainly some sort of resonance - whether mechanical
in the cartridge, or as you say electrical between the cartridge
inductance and the cable capacitance.

d

In fact I've just remembered I did have a look at how a V15 cart
responded to cable capacitance. It's he

http://www.soundthoughts.co.uk/read/cartridge.pdf

It assumes the cartridge to be nominally flat with no capacitive
loading. The peak is at about 10kHz.

d