Phono Cartridge Response Measurement Script

[GXAlan]

I thought neodymium had been in use for MM magnets for ages?

I think it is specifically the “55” version which is the extra strong neodymium.

 

[Balle Clorin]

What is going on here? Denon XG-7002 seem to have a stepwise sweep once per revolution ,but I cannot hear any steps and the scrip work/look fine. In Audacity the step/form change with windowing function. What is going on here?

Copmared wth the CA TRS-1007 record

Back to Denon XG-7002 Zoomed in with corresponding spectrum shows no level change bur frequency analysis shows a level change. I also note that the level depends om how long section of the track I choose to "scan/analyse"

I rarely ise audacity because the responsen often get this

Importing to REW as audio file gives this, staircase again

Script looks perfect.. luckily

Spoiler: how to import vinyl sweep files in REW

 

[JP]

The script slices the test signal and takes the highest amplitude frequency of that slice as the data. Multiple slices at the same frequency are averaged. This avoids pitfalls of doing an FFT of the entire test signal.

 

[melloncolliecat]

Thought of getting an E1DA Cosmos ADC for measuring and archiving purposes. But if I understand it correctly, impedance could be too low. Is something like the Cosmos Scaler needed between phono stage and the Cosmos ADC?

 

[Thomas_A]

Thought of getting an E1DA Cosmos ADC for measuring and archiving purposes. But if I understand it correctly, impedance could be too low. Is something like the Cosmos Scaler needed between phono stage and the Cosmos ADC?

Yes needed - see https://www.audiosciencereview.com/...y-phono-preamplifier-minireview-update.47206/

 

[melloncolliecat]

Yes needed - see https://www.audiosciencereview.com/...y-phono-preamplifier-minireview-update.47206/

Ah, thanks very much! I'll probably look for something easier. A handheld Zoom or similar seems like a comfortable solution if its ADC is good enough...

 

[GXAlan]

If its ADC is good enough...

Any ADC is better than vinyl. It becomes a matter of software. I like the Korg DS-DAC-10R. Sinad in the 90s probably, but ground lug and digital RIAA means that it works great.

 

[dlaloum]

Any ADC is better than vinyl. It becomes a matter of software. I like the Korg DS-DAC-10R. Sinad in the 90s probably, but ground lug and digital RIAA means that it works great.

The problem with ADC's is that to capture vinyl cleanly, you need to have a very very wide dynamic range / SNR.... because any clipping at the ADC will trigger noise throughout the frequency range (not just at the clip peak frequency) - and vinyl noise, clicks and pops, can rise more than 20db above peak signal level of the recording.

Hence when archiving vinyl, the requirements at the ADC level are extreme...

The other thing to keep in mind, is that unlike digital, with vinyl, the underlying "noise" level is also well above the lowest signal level.... so you need to record both down into the noise, as well as up well above the recording peaks - which is difficult to do.

Some analogue gain adjustement before the ADC is critical in getting the recording positioned optimally within the available signal range.

Of course all of the above are OCD perfectionist concerns - then there is the "that's good enough" perspective....

 

[Watire]

The problem with ADC's is that to capture vinyl cleanly, you need to have a very very wide dynamic range / SNR.... because any clipping at the ADC will trigger noise throughout the frequency range (not just at the clip peak frequency) - and vinyl noise, clicks and pops, can rise more than 20db above peak signal level of the recording.

Hence when archiving vinyl, the requirements at the ADC level are extreme...

The other thing to keep in mind, is that unlike digital, with vinyl, the underlying "noise" level is also well above the lowest signal level.... so you need to record both down into the noise, as well as up well above the recording peaks - which is difficult to do.

Some analogue gain adjustement before the ADC is critical in getting the recording positioned optimally within the available signal range.

Of course all of the above are OCD perfectionist concerns - then there is the "that's good enough" perspective....

Would you recommend to record thru the ADC with 24 bit resolution ?

 

[JP]

I’m sorry - that’s nonsense. 24 bit give plenty of range and there’s no need to obsess about levels. I can count the times I’ve clipped an ADC on one hand that’s missing three fingers.

 

[dlaloum]

Would you recommend to record thru the ADC with 24 bit resolution ?

Absolutely... it's the only possible way of achieving the required dynamic range! - in a perfect world, 32bit - but that's fantasy at the moment.

Once recorded, you can clean it up, and 16bit is more than ample for the end result.... 16/44 will do just fine!

But that first recording step, you need all the resolution you can get (and often more)

 

[GXAlan]

I’m sorry - that’s nonsense. 24 bit give plenty of range and there’s no need to obsess about levels. I can count the times I’ve clipped an ADC on one hand that’s missing three fingers.

+1. Meanwhile, ground loops are common when recording…

Then again, most of the vinyl LPs that I am archiving are pretty clean and the ones that aren’t clean, are fine without the last bit of detail (I.E. Disneyland’s Great Moments with Mr. Lincoln)

 

[dlaloum]

I’m sorry - that’s nonsense. 24 bit give plenty of range and there’s no need to obsess about levels. I can count the times I’ve clipped an ADC on one hand that’s missing three fingers.

A vintage 50's record with lots of wear on it.... yes I've clipped 24bit ADC's on the click/pop or scratches...

And yes it is definitely about how picky you are. - which I made clear!

 

[Balle Clorin]

Out of curiosity: Which tracks from which Ortofon records are you exactly talking about @Balle Clorin ?

1khz Left and right , used for crosstalk/Azimuth adjustments. They are good, the tracking tracks too. The sweep is horrible

 

[JP]

A vintage 50's record with lots of wear on it.... yes I've clipped 24bit ADC's on the click/pop or scratches...

And yes it is definitely about how picky you are. - which I made clear!

It's not difficult to contrive an extreme case. Doing so doesn't make the FUD a truism. The insinuation that those who don't suffer the same ADC maladies that you claim to aren't picky is fallacious. Most people have found in the vast majority of cases that there's not a lot of criticality with 24 bit levels. I've given my experience and I record flat, so at 20kHz I'm ~20dB hotter than folks who record post-RIAA. If the ADC input has fast enough recovery it's even less of an issue. I've no idea what your setup was or what the issues were, but what you're reporting isn't typical.

 

[levimax]

Regarding ADC capture, I have read the 20 dB headroom required for pops and clicks so I went through and picked out my worst damaged records and saw nothing like that. For the vast majority of even damaged LP's the peak noise seldom is higher than the peak music. In some cases with a scratched record I never play because of sever damage I saw some peaks 3-6 dB above the musical peaks. For most records, even ones that are noisy, ADC headroom is not an issue.

 

[MaxwellsEq]

Regarding ADC capture, I have read the 20 dB headroom required for pops and clicks so I went through and picked out my worst damaged records and saw nothing like that. For the vast majority of even damaged LP's the peak noise seldom is higher than the peak music. In some cases with a scratched record I never play because of sever damage I saw some peaks 3-6 dB above the musical peaks. For most records, even ones that are noisy, ADC headroom is not an issue.

I'm the same. I have used 24 bits ADCs and capture post RIAA with at least 8dB overhead on music peaks and have never encountered a popular or click more than 2 or 3 dB above peak signal.

 

[Digital1955]

There is a test record I am aware of that might be able to push the dynamic limits of your system. You do end up with more than 24 bits though when the test is complete.

 

[morillon]

can be comfortable enjoying 24bits when recording music with significant dynamic differences, classic type etc... allows you to take obvious margins when capturing...

 

[Balle Clorin]

How i that 24 bits possible when the noise floor is -60db typically