Fun with vinyl measurements

[Balle Clorin]

My player Linn Axis runs a bit slow but have not bothered yet to adjust it. Below is a kHz tone with its distortion components. Tonearm is a Moerch UP-4 and a Shure V15Vx cartridge with a JICO SAS boron stylus. Test record below is Elipson.

View attachment 112132

Pink noise on the Elipson seems to reach 17-18 kHz. The stylus has a resonance in the 12-13 khz range. Loading is 130 pF and 47 kOhm, if I remember correctly.
View attachment 112133
The 3150 tone shows 3144,5 Hz, so about 0.17% too slow. Might adjust this some day.
View attachment 112136.

Is thet

My player Linn Axis runs a bit slow but have not bothered yet to adjust it. Below is a kHz tone with its distortion components. Tonearm is a Moerch UP-4 and a Shure V15Vx cartridge with a JICO SAS boron stylus. Test record below is Elipson.

View attachment 112132

Pink noise on the Elipson seems to reach 17-18 kHz. The stylus has a resonance in the 12-13 khz range. Loading is 130 pF and 47 kOhm, if I remember correctly.
View attachment 112133
The 3150 tone shows 3144,5 Hz, so about 0.17% too slow. Might adjust this some day.
View attachment 112136.

I the frequency response measured though your RIAA or with flat/none equalisation?

 

[Thomas_A]

How do you make the polar plots?

My memory is a bit weak but I if I remember correctly you made them for me once upon a time in a thread on rec.audio. Could be wrong but at least you nickname was in that thread. Since then there have been similar software on pinkfishmedia.

Also seen this one:

http://teribil-audio.com/2012/06/software-based-wow-and-flutter-analysis/

 

[Thomas_A]

Is thet

I the frequency response measured though your RIAA or with flat/none equalisation?

Through RIAA.

 

[Balle Clorin]

AT-OC9 ML/II

 

[JP]

My memory is a bit weak but I if I remember correctly you made them for me once upon a time in a thread on rec.audio. Could be wrong but at least you nickname was in that thread. Since then there have been similar software on pinkfishmedia.

Also seen this one:

http://teribil-audio.com/2012/06/software-based-wow-and-flutter-analysis/

This python script @scott wurcer did is a lot easier.

from scipy import signal
from scipy.io.wavfile import read
import matplotlib.pyplot as plt
import numpy as np

#edit here to add a HOME directory
#HOME = "/home/david/"  #Linux example
HOME = 'C:\Users\faste\Desktop\\' #Windows example
#edit here for 45 rpm samples
Period = 1.8 # 33rpm
#Period = 4/3 # 45 rpm
#end edit

def instfreq(sig,Fs):
    z = signal.hilbert(sig)
    rawfreq = Fs/(2*np.pi)*np.diff(np.unwrap(np.angle(z)))
    rawfreq = np.append(rawfreq,rawfreq[len(rawfreq)-1])    #np.diff drops one end point
    b, a = signal.iirfilter(1,100./(Fs/2), btype='lowpass')
    a = np.convolve(a,a) #make an ordinary 100Hz 4 pole filter.
    a = np.convolve(a,a)
    b = np.convolve(b,b)
    b = np.convolve(b,b)
    instfreq = signal.lfilter(b,a,rawfreq)
    return (instfreq)

_FILE = input('Enter a .wav file (needs to be >=4sec.): ') #file needs to be >= 4 sec. 

y = read(HOME + _FILE)
Fs = float(y[0])
if np.size(y[1][0]) == 2:
    sig = y[1][:,0][0:int(Fs*4)] #Grab 4 sec of a stereo file from the first (left?) channel
else:
    sig = y[1][0:int(Fs*4)] #mono file

t = np.arange(Period,0,-1/Fs)  #Reverse time (theta axis)
theta = t*2*np.pi/Period   #Time becomes degrees (Periodsec = 2pi radians)
theta = np.roll(theta,int(Fs*.45))  #Rotate 90 deg to put 0 on top (Period*Fs/4) 

freq1 = instfreq(sig,Fs)
glitch = 2000   #remove leading glitch from output (probably should depend on Fs)
if1 = freq1[glitch:glitch+int(Fs*Period)]  
if2 = freq1[glitch+int(Fs*Period):glitch+int(2*Fs*Period)]
           
maxf = int(max(max(if1),max(if2))+.5)

r1 = 20.-(maxf-if1)/3.  #20 radial ticks at 3Hz is fixed, adaptive scaling
r2 = 20.-(maxf-if2)/3.  #is an exercise for later


ax = plt.subplot(111, projection='polar')
ax.plot(theta,r1)
ax.plot(theta,r2)
ax.set_rmax(20)
                        #Set up the ticks y is radial x is theta, it turns out x and y
                        #methods work in polar projection but sometimes do funny things

for tick in ax.yaxis.get_major_ticks():
                tick.label.set_fontsize(8)
plt.yticks(np.arange(1,21,1))
ax.set_rlabel_position(90)

myticks = []   
for x in range(0,20,1):
    myticks.append(str(maxf-57+x*3))
ax.set_yticklabels(myticks)

ax.set_xticklabels(['90'+u'\N{DEGREE SIGN}','45'+u'\N{DEGREE SIGN}','0'+u'\N{DEGREE SIGN}',\
                    '315'+u'\N{DEGREE SIGN}','270'+u'\N{DEGREE SIGN}','225'+u'\N{DEGREE SIGN}',\
                    '180'+u'\N{DEGREE SIGN}','135'+u'\N{DEGREE SIGN}'])
ax.grid(True)

ax.set_title("Instantaneous Frequency  "+ _FILE, va='bottom')
plt.show()

 

[Thomas_A]

This python script @scott wurcer did is a lot easier.

from scipy import signal
from scipy.io.wavfile import read
import matplotlib.pyplot as plt
import numpy as np

#edit here to add a HOME directory
#HOME = "/home/david/"  #Linux example
HOME = 'C:\Users\faste\Desktop\\' #Windows example
#edit here for 45 rpm samples
Period = 1.8 # 33rpm
#Period = 4/3 # 45 rpm
#end edit

def instfreq(sig,Fs):
    z = signal.hilbert(sig)
    rawfreq = Fs/(2*np.pi)*np.diff(np.unwrap(np.angle(z)))
    rawfreq = np.append(rawfreq,rawfreq[len(rawfreq)-1])    #np.diff drops one end point
    b, a = signal.iirfilter(1,100./(Fs/2), btype='lowpass')
    a = np.convolve(a,a) #make an ordinary 100Hz 4 pole filter.
    a = np.convolve(a,a)
    b = np.convolve(b,b)
    b = np.convolve(b,b)
    instfreq = signal.lfilter(b,a,rawfreq)
    return (instfreq)

_FILE = input('Enter a .wav file (needs to be >=4sec.): ') #file needs to be >= 4 sec. 

y = read(HOME + _FILE)
Fs = float(y[0])
if np.size(y[1][0]) == 2:
    sig = y[1][:,0][0:int(Fs*4)] #Grab 4 sec of a stereo file from the first (left?) channel
else:
    sig = y[1][0:int(Fs*4)] #mono file

t = np.arange(Period,0,-1/Fs)  #Reverse time (theta axis)
theta = t*2*np.pi/Period   #Time becomes degrees (Periodsec = 2pi radians)
theta = np.roll(theta,int(Fs*.45))  #Rotate 90 deg to put 0 on top (Period*Fs/4) 

freq1 = instfreq(sig,Fs)
glitch = 2000   #remove leading glitch from output (probably should depend on Fs)
if1 = freq1[glitch:glitch+int(Fs*Period)]  
if2 = freq1[glitch+int(Fs*Period):glitch+int(2*Fs*Period)]
           
maxf = int(max(max(if1),max(if2))+.5)

r1 = 20.-(maxf-if1)/3.  #20 radial ticks at 3Hz is fixed, adaptive scaling
r2 = 20.-(maxf-if2)/3.  #is an exercise for later


ax = plt.subplot(111, projection='polar')
ax.plot(theta,r1)
ax.plot(theta,r2)
ax.set_rmax(20)
                        #Set up the ticks y is radial x is theta, it turns out x and y
                        #methods work in polar projection but sometimes do funny things

for tick in ax.yaxis.get_major_ticks():
                tick.label.set_fontsize(8)
plt.yticks(np.arange(1,21,1))
ax.set_rlabel_position(90)

myticks = []   
for x in range(0,20,1):
    myticks.append(str(maxf-57+x*3))
ax.set_yticklabels(myticks)

ax.set_xticklabels(['90'+u'\N{DEGREE SIGN}','45'+u'\N{DEGREE SIGN}','0'+u'\N{DEGREE SIGN}',\
                    '315'+u'\N{DEGREE SIGN}','270'+u'\N{DEGREE SIGN}','225'+u'\N{DEGREE SIGN}',\
                    '180'+u'\N{DEGREE SIGN}','135'+u'\N{DEGREE SIGN}'])
ax.grid(True)

ax.set_title("Instantaneous Frequency  "+ _FILE, va='bottom')
plt.show()

Yes thanks. I think I read about these at DIY audio as well. I am not sure how I get these to work on my mac. I have somethimg called Python launcher but also need to load some libraries. Guess I need to study more.

 

[JP]

Install Python: https://www.python.org/downloads/

Use pip from terminal to install Matplotlib, numpy, and scipy.

Save the script to a sometqxtfile.py. I use IDLE to open the file, change the parameters, and F5 to save and run.

 

[Balle Clorin]

Thanks, but .... and what does this mean in English

Helpdesk middelalderen / Medieval helpdesk - 2001.English/Norwegian Subtitles - YouTube
select english subtitles

English remake
Medieval helpdesk in English - YouTube

 

[LTig]

.... and what does this mean in English

Helpdesk middelalderen / Medieval helpdesk - 2001.English/Norwegian Subtitles - YouTube
select english subtitles

You mean "what is a terminal? pip? IDLE?"

I love this video. Understanding the language makes it even more funny.

 

[sergeauckland]

Here's the 1kHz distortion from my Shure V15V SAS on my old Goldring GL75.
Test record is The Ultimate Analogue Test LP.

 

[sergeauckland]

As above but with the EMT TSD15 on my EMT948
Actually worse than the Shure!

 

[sergeauckland]

And finally the AT33 on my AEG TRS9000
Better, but still not quite as good as the Shure V15.

No idea what the 20kHz spike is on the EMT and AEG plots.

Interesting also the different amounts of LF rubbish on the three plots.

 

[solderdude]

One does not want to know the calculated SINAD on those otherwise fine sounding vinyl records.

 

[Thomas_A]

Data for the Linn Axis a la 1987

https://www.gammaelectronics.xyz/audio_05-1987_linn.html

With wow & flutter app on my Axis.

 

[sergeauckland]

Here are my W&F results.
GL75

EMT948

AEG TRS9000

No idea what the W&F residual on the LP is.

S.

 

[Thomas_A]

Sometimes I wish we could use some standard to relate the numbers to. What is speed stability vs wow & flutter vs long-term drift, weighted and unweighted? I have no idea what the wow and flutter app measures, weighted or unweighted? And what is the precision of the app?

 

[Balle Clorin]

My Michell Gyro SE. Here is when I had 0.05% peak in the Iphone app before I messed up the setup (suspension-belt-oil -hange).. Now I am on 0.1% on the app. GRRRR"!! don't fix it if it aint broken...

''
Notice how the Unweighted (Wrongly labeled DIN unweighted ) value is always higher than the RMS DIN weighted. The RAW deviation suffers from aliasing since WFGUI gives 1 sec data speed data in the log file while the main speed variation is once per 1.8 sec.


On apps: I chatted with Philip Broder that made the W/F wow and flutter for I phone also also the Iphone RPM app. The values given is the maximum deviation from average the W/F app the max for the last 4 revolutions.Thos is not the same as the IEC standard w&f % The DIN norm is quite complicated , but can be found by Google. The WFGUI has correct implementation of the standard.

Using Audacity with the wow&flutter add-in, is quite useful. Especially if you export the data to a wav file and analyze it with RightMark

An now some longer term drift/belt tension adjustments

 

[abdo123]

Technics SL1200-Mk2 + Ortofon 2m blue. (5cm/s)

View attachment 111899

And rpm stability is excellent due to crystal oscillator driven direct motor drive.

Btw is the Ortofon 2M Blue neutral over the entire frequency range? It would be nice if you happen to have any further measurements off that cartridge in particular. It appears to be the best bang for the buck before tip-toeing in snake oil territory.

 

[watchnerd]

Nice .
How long period is this over? German audion magizine Stereoplay/audio use 20 sec.(longer period are likely too look worse on belt drive with DC motor due to drift....1 15 minute period doss not look as good at 20 sec on mine


Here is my Michell Gyro SE compared with Technics SL-1500 direct drive over 20 sec. same scale. This day the Gyro gave 0.05% peak variation in Phili Broder app.
View attachment 111944

correctly scaled
View attachment 111949


I also measured a Michell Technodec to 0.06% variation the same as I got on a Technics S1200 GR
Both have the same 0.06 % peak variation, bit the Technics is spot on speed. (+0.24%= 33 1/3 on my phone), The Technodec is too fast with the standard PSU, that is why people should get the HR supply for easy speed adjustment.

View attachment 111945
View attachment 111946

View attachment 111947
View attachment 111948

NOTE!! Phone must be placed on record center. I use a record clamp over the spindle to support the phone in center

you screw the clamp down on top of the phone?

 

[watchnerd]

Nice .
How long period is this over? German audion magizine Stereoplay/audio use 20 sec.(longer period are likely too look worse on belt drive with DC motor due to drift....1 15 minute period doss not look as good at 20 sec on mine


Here is my Michell Gyro SE compared with Technics SL-1500 direct drive over 20 sec. same scale. This day the Gyro gave 0.05% peak variation in Phili Broder app.


correctly scaled
View attachment 111949


Both have the same 0.06 % peak variation, bit the Technics is spot on speed. (+0.24%= 33 1/3 on my phone)

Here's what I got today with my Gyro SE using the WowFlutter app:


wow/flutter: 0.17%
average RPM: 33.35
33 1/3 +.05%

I'm pretty happy with that speed accuracy for a belt drive, but the w&f could be better.

I'll have to contrast with a test where there isn't a phone lying on the top.