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Cutting Electronics
Old 8th March 2003
  #1
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Cutting Electronics

Tim,

Could you give some details about the cutting amps you designed for The Exchange? Did you also design high frequency limiters and an elliptical EQ?

Are you familiar with the EMI vertical acceleration limiter at Abbey Road? It seems like a unique and usefull piece. Any details on its mode of operation would be appreciated.
Old 8th March 2003
  #2
Gear Head
 

Disc Cutting systems

At the EXCHANGE I do not build in any High Frequency Limiting. Nor did I build in so called Elliptical Filter which is just glorified bass monoing. If I need HF limiting then I used my moddified Valley People De-esser.
As to EMI the vertical is done by sum and differencing so that the vertical is limited on the difference signal. It can help to give 3dB
subjective treble brightness as a total sound.
I cannot divulge the propriotery information of the electronics. They are the same as I have installed at MOBILE FIDELITY in Sabastoplol California. As they are going to get back to reissueing on 200 gram vinyl back catalogue.
Tim de P
Old 8th March 2003
  #3
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Re: Disc Cutting systems

Quote:
As to EMI the vertical is done by sum and differencing so that the vertical is limited on the difference signal. It can help to give 3dB
subjective treble brightness as a total sound.
I didn't know if it worked as you described or if it summed the the channels dynamicaly. Limiting the difference signal does seem easier to impliment. I could use one dual mono compressor for the preview and program difference signal and pass the sum signals straight through. I guess I would also need a side chain with a steep LPF to trigger the compressor.
Old 9th March 2003
  #4
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Re: Re: Disc Cutting systems

Quote:
Originally posted by Paul Gold
I guess I would also need a side chain with a steep LPF to trigger the compressor.
You don't want an LPF, any high level difference signal can cause enough vertical to make a stylus jump out of the groove, not just LF. You may also want to set the threshold higher on the preview difference limiter, or not use one at all, to get some extra groove depth on the sections that are being limited by the program difference limiter... (I used to cut with an EMI TG console in the early eighties).
Old 9th March 2003
  #5
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Re: Re: Re: Disc Cutting systems

Quote:
Originally posted by ottor
You don't want an LPF, any high level difference signal can cause enough vertical to make a stylus jump out of the groove, not just LF.


I haven't found that to be the case. There is plenty of acceleration from 1k up in program but little velocity. It's the velocity that causes tracking errors. When I set up the variable pitch and depth I use reverse polarity tones to see the vertical velocity. By the book. From about 600hz and up at 0vu there isn't enough vertical velocity for tracking problems. At least the way I have it set up. I have visual rules for what is an acceptable vertical velocity depending on base depth. And I'm pretty conservative.

Quote:
You may also want to set the threshold higher on the preview difference limiter, or not use one at all, to get some extra groove depth on the sections that are being limited by the program difference limiter... (I used to cut with an EMI TG console in the early eighties).
I don't use a sum/difference limiter presently for cutting. It's too invasive. What I really want is a 'dynamic elliptical EQ'. Something that only sums the low end when necessary. I thought the VAL might be that. I use an elliptical EQ a lot. It does the trick. I also do a lot of playing around with how the variable pitch/depth is set up for each lacquer. I don't have a fancy Zuma so I have developed a good feel for base pitch and level offset settings based on the frequency content/level of the program. This is more for avoiding over cuts and packing the grooves tight though.
Old 9th March 2003
  #6
Gear Head
 

Disc Cutting and treble difference limiting,

I still am not sure why you want eliptical filtering unless you want to get the job done quickly. All the stuff I did for Waterlily or Chesky had lots of antiphase low end and just doing my homework on anylizing the tapes for the difficult bits till I got them to go right. I tend never to use vari pitch but make up a time sheet and do it all manually. I dont like the low end thumps from fast pitch and depth. Let the groves kiss now and again. Test playback with the Stanton disco special for misstraking etc.
On the vertical as long as it does not skip or crash into the Aluminium substrate gently increase the depth for the duration of that passage.
On Rock & Roll most of its loud most of the time and keeping to 24 minutes max you should have no difficulty averaging 0 vu to + 2 relative to 7 cms NAB 7inch singles
At the EXCHANGE many 12 inch 45's last only 7 or 8 mins
so run at about 120lines/inch and on DUB PLATES( Reggae) the bass will excede 100 microns sometimes nearer to 200 microns
Neuman or westrex heads. Ortophon cant handle the mechanical excursions.
The Germans were great at the lazy way of cutting. and just quote the DIN standard of boring low mod levels. Because their engineers just sclep the tape on and go using limiters and eliptics and preview computors. so dull and thin records wonderfull.
On the preview head come electronics it really does not matter about the top end and we never bother to EQ it as if it controlled to the last micron. We couldn't even be bothered to azimuth the preview. I have difficulty stopping Mobile Fidelity from going down the vari groove with some fancy Swiss computor to nestle in perfection of groove packing never mind what it does for the sound.
Tim de P
Old 10th March 2003
  #7
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Re: Disc Cutting and treble difference limiting,

[QUOTE]Originally posted by TimdeParavicini
[B]I still am not sure why you want eliptical filtering unless you want to get the job done quickly. All the stuff I did for Waterlily or Chesky had lots of antiphase low end and just doing my homework on anylizing the tapes for the difficult bits till I got them to go right.
[QUOTE]

I do need to get the job done quickly in most cases. I scan the sides, do a short test cut and then let it fly. If I don't like the side I'll do it again but I try not to. I don't deal with audiophile type clients. They go to people like you. I have mostly electronic music, indie rock and rap. For singles I cut fixed pitch. For LP's the budget has usually been spent on the CD mastering. So spending a day charting out moves isn't in the budget. They wouldn't even do that at the big houses here without a special request. I don't see the elliptical EQ as being too evil. If the low end is in phase it's pretty transparent. If it isn't in phase I'd need to use it anyway. Unless I spent the day charting it all out. I try to use the high frequency limiters for protection only. It's not minimalist and audiophile but I think it's taseful and fairly transparent.


[QUOTE]
On Rock & Roll most of its loud most of the time and keeping to 24 minutes max you should have no difficulty averaging 0 vu to + 2 relative to 7 cms NAB 7inch singles
[QUOTE]

That sounds right with a nominal groove depth of about 2mil.


[QUOTE]
At the EXCHANGE many 12 inch 45's last only 7 or 8 mins
so run at about 120lines/inch
[QUOTE]

One of the most common things I hear from electronic music clients is 'Make it sound like The Exchange'. Many of those singles are smashed hard. On Friday I was able to really smash a house single without losing high end. It made me happy. It was a 12" 45. Kissing grooves at 100 lines/inch 4mil depth. I've seen a number of singles from The Exchange like this.
Old 10th March 2003
  #8
Gear Head
 

Loud Cutting

In response, Yes on a day to day basis for money's sake Then use the devices. My comments were really for absolute standards, i,e. Audiophile. But some people expect that. Pink Floyd for example have always tried to set audiophile standards.
The Echange like most mastering houses have 98 per cent
techno morons who bring in their DAT's baddly recorded that you have to pull a lot of tricks out of the hat. and they don't want to spend any money. Unfortunately, we all have to do jobs that we are not keen on!!!
Thankfully, I still get a buzz out of doing something right.
On most of that dat clients because of their poor monitor speakers end up pretty much MONOish.so the bass is fairly centred to get max noise out of 2 speakers. its the acoustic live music that tends to have the antiphase. As to treble again a lot of that is not often hard right or left.
Once again I appreciated the nice comment about being asked to try and match their work. Lots of engineers don't try to improve their targets. I hope that you will continue to strive for quality so we can chew the fat.
Tim de P
Old 10th March 2003
  #9
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Re: Loud Cutting

I do strive for quality if only for it's own sake. As a one man shop in NYC I'm not likely to see the top 2% either budget and/or sound quality wise. I'd like to think I'm ready for them if they magicaly appear though. I'm not an audiophile by temprement and I enjoy working with morons of all stripes. The people who are talented and therefore repeat clients also strive for quality no matter what the type of music. I have some very picky electronic music producers who know the difference.

Since CD's are mastered so bright these days the high frequency limiters help more than hurt for the most part. When the music gets loud the highs get trimmed a little. Our ears like this. I think one of the reasons people like vinyl is because to get a good mix you can't take the easy way out and crank the high end to gain clarity.

Off topic: If I wanted to interface your 834p preamp to a balanced system what would you recommend? I'm in noisy mid town Manhattan so balanced it is. I know you custom spec all your transformers.
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