How to map and EQ your dynamic cutterhead

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Fattcamp
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Re: How to map and EQ your dynamic cutterhead

Post: # 65898Unread post Fattcamp
Wed Oct 09, 2024 6:49 pm

After re-reading your last post markrob, I see you referred to cutting at a lower level as opposed to what I thought you said (slower cutting speed than 33-1/3). I think I had a limiter to bring the volume up on those tracks a bit so they weren't too quiet if that's what you're referring to.

Still curious if even slower platter speed could help out a bit more but just don't have the ability right now.

Dave

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markrob
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Re: How to map and EQ your dynamic cutterhead

Post: # 65900Unread post markrob
Wed Oct 09, 2024 9:22 pm

Hi Dave,

Yes, I was referring to the cutting loudness. The louder you cut, the more the self erasure of the embossing stylus can come into play. So that's a tradeoff. You already probably have to cut lower than a commercial release due to the shallow grooves of embossing. So, cutting even lower might not be feasible. But its worth trying just to see if the limit is due to self erasure. Also, make sure you are not wasting amp power by hitting the head with energy outside of the bandwidth that you can really achieve. Were you maxing out the peak power of your amp? If so, try to place a steep low pass at the end of the chain adjusted to remove any energy that you don't want. Looks like you could get really aggressive at around 9Khz when cutting 33 for 45. That would put a hard limit at around 12Khz on playback.

Mark

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CutR
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Re: How to map and EQ your dynamic cutterhead

Post: # 65903Unread post CutR
Thu Oct 10, 2024 11:04 am

To equalize a mono moving iron head cutting at 78 for 33 or 45 playback, is the process the same as STB decribed earlier?

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Fattcamp
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Re: How to map and EQ your dynamic cutterhead

Post: # 65904Unread post Fattcamp
Thu Oct 10, 2024 1:33 pm

markrob wrote:
Wed Oct 09, 2024 9:22 pm
Hi Dave,

Yes, I was referring to the cutting loudness. The louder you cut, the more the self erasure of the embossing stylus can come into play. So that's a tradeoff. You already probably have to cut lower than a commercial release due to the shallow grooves of embossing. So, cutting even lower might not be feasible. But its worth trying just to see if the limit is due to self erasure. Also, make sure you are not wasting amp power by hitting the head with energy outside of the bandwidth that you can really achieve. Were you maxing out the peak power of your amp? If so, try to place a steep low pass at the end of the chain adjusted to remove any energy that you don't want. Looks like you could get really aggressive at around 9Khz when cutting 33 for 45. That would put a hard limit at around 12Khz on playback.

Mark
Hey Mark,

That makes sense. I'll do some testing at lower volume to see if it makes any difference. I'll also take your advice on eliminating any extreme frequencies outside of the range I'm able to cut. I played around in my DAW last night with the latest 33 for 45 test and after the big HF dip, the leftover information is barely audible and unnecessary for sure.

Regarding the peak power of my amp, I'm not really sure. The amp I'm using is an ART SLA-2 (https://artproaudio.com/installation/product/206801/sla2). I'm keeping my amp volume at half (-18dB / 12:00) for an easy visual, and the audio being sent to it gets adjusted on the computer so the signal lights are just starting to flicker on the amp. Apparently the amp signal lights trigger when the output is appx 30dB full scale. I don't fully understand that info, but that's technically what's happening. I was wondering if I should be kicking up the amp volume and lowering the audio being sent from the PC but didn't want to introduce unnecessary amp noise.

Regarding EQ, now that I'm getting better results doing the match-eq in the pitched down state, I'm trying to understand how/when to apply the HF limiter. This is mainly throwing me off because my HF limiter (Acceleration2) is a fixed frequency. If I apply it pitched down, when pitching back up, the HF limiting will be way beyond the frequency range that's being cut, so perhaps I should use a different limiter while pitched down... or apply the Accelerator2 before pitching down. The problem with applying the HF limiter before pitching down & eq changes, is that it won't be as effective as opposed to after those changes to keep things in check.

I'm still scratching my head why doing the match-eq in the pitched down state gets better results than match-eq at regular pitch and then slowing down pitch... which should be doing the same thing. Either way, it works. I just prefer those types of adjustments at regular speed.

Thanks,
Dave

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diy_cutter
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Re: How to map and EQ your dynamic cutterhead

Post: # 66177Unread post diy_cutter
Sat Nov 16, 2024 4:56 pm

Here is my version of the head EQ setup.

0. Calibrate playback from the turntable to 0dB using a test record. Make notes on the level indicator (or remember) for different test cartridges, if there are several. Their output levels will be different.

1. Adjust the recording level in the computer, using the controls on the sound card/preamplifier/phono preamplifier or programmatically so that the 0dB level on the indicator is -6 (like mine), -9 or -12 dB. This is needed to provide some reserve when digitizing the recorded material. You conditionally take this value as 0dB. When setting to -6dB, if you record a +4dB signal when creating an equalizer, the scale will show you -2dB. Your recording will not clip or overload. After all, when recording digitally, everything above 0dB is cut off.

2. Prepare several rich full-range pieces with male and female vocals in different styles. Make each piece fade-in and fade-out. Align everything to -23 LUFs. Combine into one file with small gaps. I use 7 pieces of different music, 30 seconds each.

3. Start cutting from the minimum level and raise it until you get a recording of about +2-4dB above 0. STB has already written that this will show the resonances of your head. After adjusting the level, start the recording for cutting first, so that you can then get a digital copy for comparison. If possible, make two cuts - at the beginning and at the end of the workpiece. These will be two different recordings. With their help, you can make different equalizers, for example, a brighter equalizer will be made from a piece at the end of the disk, it will be suitable for recording on 7 inches or for dull tracks (so as not to deal with unnecessary preliminary equalization).

4. So, make a digitization. Align it by volume with the original file to -23 LUFs. Using EQ Match, compare the pieces and get an equalizer for your head. Depending on the number of pieces in your test recording, you will get a number of different EQs. You take the one with the maximum rise in high frequencies. Apply it to the entire test recording and cut again. Digitize again and compare with the original. Note that the track from which you chose the equalizer preset will become maximally linear on the graph. Something like the picture below. This will be the correct and fairly universal setting. Save this equalizer as an additional one.

When digitizing for such tests, do not use cheap cartridges like AT3600, but do not use expensive or bright-sounding ones with Microline, Shibata etc. sharpenings, any elliptical sharpening and a cartridge within 150-300 dollars / euros will be optimal. Ortofon 2M Red or Audio-Technica VM520/95 are great.

In my experience, it is 2 sequential equalizers that work best. First the first, and then the second based on the cut using the first. You can add compressors before the equalizers, monotonize the Bass to 200-300 Hz, apply a de-esser. And at the end, after the equalizers, you can add a limiter with the most transparent settings. But this will already be "Your sauce"! Its taste is selected for a long time, sometimes months. Plus, it will need to be done again for different heads, and sometimes blanks, their color, thickness, heating parameters, cutter length (especially important after re-sharpening) and much more.

Do not be afraid and experiment! It is fun and expensive, because you will ruin a lot of blanks and cutters! But it is worth it!
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