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Topic: Sibilance in LPs (Read 8290 times) previous topic - next topic
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Sibilance in LPs

Hi. I'm new on this forum. I've started recording my LPs using Audacity on my Mac (OS 10.3.9). I'm getting very good results, but I've noticed that some LPs have a lot of sibilance in the vocals. Not all do, only some of them, and it's so harsh that the S's sound like a very loud and high and sharp SSSHHHH sound. Also, on these same records the same thing can be heard in the T's, and similar sounds. Now these are records I haven't played for a while because my turntable didnt' work for several years and I've just replaced it last summer with a new Sony turntable (don't know the model offhand - I'm at work at the moment), and a Stanton cartridge. I know that the last time I played these particular records there was no sibilance at all, and it's so harsh and prevalent that I don't believe it was recorded that way. Everything else sounds just fine, the music, etc., no distortion; just the S's. Can an LP be damaged just by sitting around for a while? What can cause this?

I've tried de-essing the files in Audacity using a de-essing filter, but it doesn't help at all. The only thing that does help is something I read on another audio site somewhere, where someone said to select the S sound and amplify it (or DE-amplify, might be a better word) to -6 dB. I've tried this, and it does help, and in some cases fixes it, but it's a lot of work and isn't perfect.

Does anyone have any advice on how to deal with this problem, either before recording or after?

thanks so much,

Jack

Sibilance in LPs

Reply #1 –
The only way LPs could change over a few years of storage is by getting dirty or by warping, neither of which is likely to produce the symptoms you are describing.

Different cartridges can sound different and this kind of sound may be one of the places that can show up. The easiest test is to play one of the problem disks on a different system.

Cartridge setup and alignment is important to results. I'm not sure how much in regard to what you are describing, but certainly distortion and noise are effected.

Prevention is always better than correction. However, I've read a recommendation for the de-esser produced by dbAudioware - http://www.db-audioware.com/dbs.htm
I have no personal experience.

It appears that link no longer works. I don't know if that company is still in business or not

The company is there at www.db-audioware.com
I did not look for the de-esser

Sibilance in LPs

Reply #2 –
You could also just equalize out the 's' region of the frequency spectrum. I forget where that is exactly but it would be pretty visible on Audacity's spectrogram. You should only need to do that once per file. A particular type of cartridge, or a strangely loaded cart, or a preamp with a treble-boosted response could do this.

Does it get worse towards the end of the records (near the inner groove)?

Sibilance in LPs

Reply #3 –
Quote
You could also just equalize out the 's' region of the frequency spectrum. I forget where that is exactly but it would be pretty visible on Audacity's spectrogram. You should only need to do that once per file. A particular type of cartridge, or a strangely loaded cart, or a preamp with a treble-boosted response could do this.

Does it get worse towards the end of the records (near the inner groove)?
[a href="index.php?act=findpost&pid=354879"][{POST_SNAPBACK}][/a]


No, it doesn't get worse near the end, it seems pretty uniform all the way through.

How do you read a spectogram? I've looked at it, but it doesnt' mean anything to me (can you tell I'm an audio neophyte?). If I could figure out what the frequency was I might be able to filter it out. Meanwhile, I'll see if I can play one of the records on a different turntable to see if that is a factor.

Sibilance in LPs

Reply #4 –
Are the S just louder, like when you boost the treble control, or distorded also ?
In the later case, your stylus can be worn or broken (in this case, playing the records with it can damage them)
The stylus can be dirty (with a big mess of dust around the tip)

It is also possible, though it should not affect the sound this much, that your tracking force it too weak. Some Stanton cartridges can stand up to 7 grams. Refer to the cartridge manual, or to the Stanton website ( http://www.stantonmagnetics.com/v2/carts.asp ) to know what tracking force you should set.

Sibilance in LPs

Reply #5 –
Quote
Hi. I'm new on this forum. I've started recording my LPs using Audacity on my Mac (OS 10.3.9). I'm getting very good results, but I've noticed that some LPs have a lot of sibilance in the vocals. Not all do, only some of them, and it's so harsh that the S's sound like a very loud and high and sharp SSSHHHH sound. Also, on these same records the same thing can be heard in the T's, and similar sounds.[a href="index.php?act=findpost&pid=354865"][{POST_SNAPBACK}][/a]

This could be a cartridge setup problem (incorrect alignment and/or tracking force too low), leading to mistracking. If it is, then you really *must* get it sorted out immediately - mistracking is the quickest way to permanently damage your LPs. One way to know if your problem is mistracking is that you'll hear distortion on all loud sections, not just 'S' sounds in vocals. If you can play a loud instrumental section without noticable break-up, then it's probably not mistracking.

Assuming you don't have a mistracking problem, the next most likely explanation is that the capacitance on your phono preamp is too low for the cartridge. All moving magnet cartridges have a high frequency resonance in their response, and rely on the input capacitance to tame this. Different cartridges require different amounts of capacitance to achieve a (nominally) flat frequency response. If your phono preamp has adjustable input capacitance, try fiddling with that. Back in the days when vinyl was the standard medium, it was possible to buy interconnects with differing capacitances to address this issue: I have no idea whether that is still the case. You can always experiment with adding in additional capacitance to the phono input: try adding 50/100/200pF between the signal and ground pins.

Sibilance in LPs

Reply #6 –
Quote
Are the S just louder, like when you boost the treble control, or distorded also ?
In the later case, your stylus can be worn or broken (in this case, playing the records with it can damage them)
The stylus can be dirty (with a big mess of dust around the tip)

It is also possible, though it should not affect the sound this much, that your tracking force it too weak. Some Stanton cartridges can stand up to 7 grams. Refer to the cartridge manual, or to the Stanton website ( http://www.stantonmagnetics.com/v2/carts.asp ) to know what tracking force you should set.
[a href="index.php?act=findpost&pid=354917"][{POST_SNAPBACK}][/a]


No, the S's are not just louder, they're distorted, and very harsh. The stylus is pretty new, bought it earlier this year and haven't used it that much until a couple of months ago. Also, I do clean it before each record with a little stylus brush. The rest of the music sounds fine, it's just the S sounds (and T's, etc., all those explosive sounds). Other high sounds, like cymbals seem to be OK. Thanks for the link to the Stanton site, I'll take a look there.

Jack

Sibilance in LPs

Reply #7 –
This could be a cartridge setup problem (incorrect alignment and/or tracking force too low), leading to mistracking. If it is, then you really *must* get it sorted out immediately - mistracking is the quickest way to permanently damage your LPs. One way to know if your problem is mistracking is that you'll hear distortion on all loud sections, not just 'S' sounds in vocals. If you can play a loud instrumental section without noticable break-up, then it's probably not mistracking.

Assuming you don't have a mistracking problem, the next most likely explanation is that the capacitance on your phono preamp is too low for the cartridge. All moving magnet cartridges have a high frequency resonance in their response, and rely on the input capacitance to tame this. Different cartridges require different amounts of capacitance to achieve a (nominally) flat frequency response. If your phono preamp has adjustable input capacitance, try fiddling with that. Back in the days when vinyl was the standard medium, it was possible to buy interconnects with differing capacitances to address this issue: I have no idea whether that is still the case. You can always experiment with adding in additional capacitance to the phono input: try adding 50/100/200pF between the signal and ground pins.
[a href="index.php?act=findpost&pid=354993"][{POST_SNAPBACK}][/a]
[/quote]

Oh boy, I really have no idea what capacitance really means! How would I add capacitance between the signal and the ground pins? Is there some kind of module I would get and put in the line before plugging the turntable into the amplifier?

As far as mistracking goes, I don't think there is distortion in all the loud sections uniformly; I think it's just the S sounds, not the music. I'll check that again, though, before I do anything.

thanks,
Jack

Sibilance in LPs

Reply #8 –
Quote
Oh boy, I really have no idea what capacitance really means! How would I add capacitance between the signal and the ground pins? Is there some kind of module I would get and put in the line before plugging the turntable into the amplifier?[{POST_SNAPBACK}][/a]

I doubt anyone makes a module for this.

To add capacitance, just get hold of some cheap ceramic disc capacitors from an electronics supply store - they cost just a few pennies each. As a first experiment, I'd suggest you get some 300pF ones. (That's 300 PICO-farads, not micro or nano). This is likely to be way more than you need, but if installing them results in the sibilance going away (probably with some loss of treble), it at least suggests you're on the right track, and then you can start trying out different values. (Come to think of it, since they're so cheap, you may as well just buy a range at one time: values around 50pF, 100pF, 150pF, 200pF and 300pF - the exact values aren't critical. Two of each, of course - one per channel).

To install, you need to find some way of attaching a capacitor across the signal lead: one leg on the signal pin, the other on the ground pin/ring. If it were me, I'd open up the phono preamp or turntable, find the back of the phono sockets and hold the capacitors in place with solder or small croc clips. If you can get inside the phono plugs on your cables, you could even install a capacitor inside those.

I realise that some people may not feel confident trying to do this, but if your problem *is* the wrong capacitance, then there's little option but to get it sorted out. Do you have any friends who are handy with things like this?

I'm not saying your problem is definitely capacitance, but it's a possibility that needs to be considered. But for sure the first thing you must do is make sure you're not mistracking - 'S' sounds are the first ones to show it up. Check the recommended tracking force of your cartridge and set it to the maximum (but not higher). Also make sure that the cartridge is properly aligned in the turntable's headshell - it should be parallel to the grooves at two points across the record's surface at about 70mm and 125mm from the spindle. You can [a href="http://www.enjoythemusic.com/protractor1.pdf]download a PDF file of a protractor[/url] to help with this.

Sibilance in LPs

Reply #9 –
Just reading all the possible reasons for the sibliance, and the cures for this problem in LP's only serves to remind me again why I am glad we have CD's now. 
Nov schmoz kapop.

Sibilance in LPs

Reply #10 –
Thanks very much, cliveb, for your suggestions. I've printed out the protractor and will check the stylus alignment. Your description of how to put in the capacitors is pretty clear, and I ought to be able to do it myself. But I do know one or two people who are more electronically literate, so I'll get help from them if necessary.

Thanks again,

Jack