Distortion when recording from vinyl

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Distortion when recording from vinyl

Permanent link to this post Posted by jasongnome » Sun Dec 31, 2017 8:55 pm

I'm certain this is a problem pre-Audacity.

I'm using Windows 10 and Audacity 2.1.2.

Recording from a Numark DJ deck via a Citronic AC-1USB

The problem only occurs with some high level recorded vinyl, only ever 12" singles, never LPs or 7"s. The sound is distorted, the same sort of distortion sound I get if I have Audacity's recording volume set so high that it clips. But I get the sound no matter how low I have the recording volume set and it isn't clipping. The sound wave looks distorted, ie it flattens at the peaks, even though they're well below the 1dB mark with the recording level down.

My gut feeling is that the level is too high going INTO the pre-amp, and the Citronic level controller only affects line input, not phono imput (I did as a last resort try switching to line input, but, unsuprisingly that sounded terrible!).

There's no input control on the Citronic and no output control on the turntable. Is there likely to be any solution to this? Could the problem be the turntable itself, or would adjusting the tonearm weight help? I'm using a Stanton 500 cartridge, the stylus itself is fairly new, but the cartridge is pretty old, would a knackered cartridge produse this effect?

Any help appreciated.
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Re: Distortion when recording from vinyl

Permanent link to this post Posted by steve » Sun Dec 31, 2017 10:00 pm

jasongnome wrote:My gut feeling is that the level is too high going INTO the pre-amp, and the Citronic level controller only affects line input, not phono imput

That's possible.

jasongnome wrote:I did as a last resort try switching to line input,

Please post a short sample of that, and a short sample using the phono input. Just a few seconds of each will be fine, preferably of the same loud audio, in WAV format.
See here how to post audio samples: https://forum.audacityteam.org/viewtopi ... 49&t=72887
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)
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Re: Distortion when recording from vinyl

Permanent link to this post Posted by jasongnome » Mon Jan 01, 2018 9:01 am

Thanks for the prompt reply. I have to go out now, but I'll record and post a sample when I get in this afternoon. Would a screenshot of the wave be useful as well?
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Re: Distortion when recording from vinyl

Permanent link to this post Posted by jasongnome » Mon Jan 01, 2018 12:25 pm

audsomeone.png
audsomeone.png (162.78 KiB) Viewed 139 times

someonephono.wav
Using phono input
(1.04 MiB) Downloaded 9 times

someonelinein.wav
Using line input
(946.04 KiB) Downloaded 7 times


In the image, the first section is using the phono input and the second the line input (with the recording volume turned up to get a reasonable signal, the bit in the middle is line with the recording volume set the same as the phono bit).
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Re: Distortion when recording from vinyl

Permanent link to this post Posted by flynwill » Mon Jan 01, 2018 5:09 pm

Yep it is clearly clipping.

The lack of any base in the bit you recorded on the "line" setting makes it clear there's no phono preamp hiding in the Numark Deck.

The Stanton cartridges always were relatively high-output devices.

Possible fixes:

1) Build an attenuator to go between the turntable and the Citronic. Not hard if you have experience soldering electronic components.

2) Buy a stand-alone phono preamp and connect it in between the turntable and the Citronic, then run the Citronic in "line input" mode. Hopefully this will allow you to use the gain control in the Citronic to get the level below clipping, but stand-alone phono preamps are fixed gain devices, so with a high input level they may still produce an output that is too big for the Citronic, or possibly even add their own clipping.

3) Replace the Citronic unit with a different brand such as the Behringer UFO-202. But again no guarantees you won't have the exact same problem.
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Re: Distortion when recording from vinyl

Permanent link to this post Posted by jasongnome » Mon Jan 01, 2018 5:45 pm

OK, thanks, looks like the attenuator is the best option. I don't have the skills to make one, but I have friends that do.

Another options that seems possible, if the Stanton is know for a high output, would just changing the cartridge be likely to work?
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Re: Distortion when recording from vinyl

Permanent link to this post Posted by flynwill » Mon Jan 01, 2018 6:15 pm

Changing cartridges would be another roll of the dice as to whether or not that would fix the problem.

However, it might be a good excuse to move away from a "DJ cartridge" for transcribing your Vinyl, something with an elliptical stylus perhaps. I have a Grado, and can say that it is significantly less sensitive than others, it is also much more susceptible to hum pickup so that could be a problem.

Do put the Stanton back before you start back-queuing or scubbing on that DJ deck however.

This will get you 6dB of attenuation (assuming that your phono input is the standard 47k), that will probably be enough to solve the issue. Install the attenuator as close as possible to the preamp.
Attachments
2017_12_31_16_57_39.jpg
2017_12_31_16_57_39.jpg (6.29 KiB) Viewed 129 times
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Re: Distortion when recording from vinyl

Permanent link to this post Posted by kozikowski » Mon Jan 01, 2018 7:08 pm

Just a note. None of the waveforms ever gets above 0.5. That's a red flag under other circumstances. Did you do that just for display purposes and the waves naturally overload at or close to 1.0 (0dB)?

Yes, the illustration I saw says the adjustment is "Line Input Gain."

No-one would be shocked if a "Dance Groove" recording played on a "Dance Turntable" with a "Dance Cartridge" was hot, although I never had troubles with the Numark mixers. But then, how would anybody know? Floor volume is graded on how quickly you could melt a wax candle through sheer sound pressure level.

I never had any trouble with my Grado cartridge.

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Re: Distortion when recording from vinyl

Permanent link to this post Posted by jasongnome » Tue Jan 02, 2018 9:26 am

kozikowski wrote:Just a note. None of the waveforms ever gets above 0.5. That's a red flag under other circumstances. Did you do that just for display purposes and the waves naturally overload at or close to 1.0 (0dB)?


The left side of the image is using the phonol input, but you can see I have the recording volume set quite low, adjusting the recording volume makes the mawe bigger or smaller, but doesn't cgange the shape, the flattening is before it gets as far as the laptop.

No-one would be shocked if a "Dance Groove" recording played on a "Dance Turntable" with a "Dance Cartridge" was hot, although I never had troubles with the Numark mixers. But then, how would anybody know? Floor volume is graded on how quickly you could melt a wax candle through sheer sound pressure level.


Yeah, I think I might try a cartridge change first, TBH, now I'm no longer DJing I could use a more appropriate cartridge for recording. I'll probably get a new headshell as well so if I do end up using the deck for any DJ type stuff I can easily change it back.
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Re: Distortion when recording from vinyl

Permanent link to this post Posted by jasongnome » Thu Jan 11, 2018 2:10 pm

Thanks for the help! The problem seems to be solved.

Looking at the replies I got in this thread, particularly the confirmation that my hunch was right about it clipping the pre-amp before it even got to Audacity, and the info that the Stanton cartridge was known to have a high output, I decided to invest in a new cartridge.

I'm not exactly flush atm, and didn't want to spend a huge amount on something that might not work so I looked for a cheapish cartridge with decent reviews and settled on the Audio Technica AT95E, which is elliptical, as suggested. This has good reviews all over the place, with the main negative I saw was someone complaining the slightly low output, which seemed to be a plus considering my particular issue. I bought one new and ready mounted on a headshell (meaning I can easily replace the Stanton if I want to do anything that requires it) from Amazon. It arrived today, I installed it, adjused the tracking and weight to the manifacturers recommendation and tried it out. All of the records that distorted before sound fine with this cartridge.

Once I've got bit of money again, I'll probably invest in something higher spec, but it good to have the problem solved. Thanks again.
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