You are here

How stable are record decks in terms of tempo/pitch?

All about the tools and techniques involved in capturing sound, in the studio or on location.

How stable are record decks in terms of tempo/pitch?

Postby Sosabba » Wed Feb 07, 2018 1:46 pm

Hi all

I used to DJ many years ago, using vinyl. It's something I mean to get back into at some point, but for a variety of reasons I think I'll go down one of the digital routes if/when that happens.

Part of the plan will be to digitise all of my vinyl (around 600-700). But that got me to thinking how stable my decks are in terms of speed / tempo / pitch. When I did mix way back when I used to beat match, and the two records would always drift slightly and need constant tiny adjustments. I never did fully understand whether that was inherently a vinyl thing or just me not being that good at it! One of the attractions with vinyl would be more stability, but if I am playing an unstable recording of a digitised vinyl, then I guess I'd still be in the same boat.

Any thoughts on this would be most helpful.

I should add that my decks are Numark TT-1s (direct drive) and they do have a Quartz button. But would Technics be more stable? Or would a HiFi deck be a better choice? Are there any turntables which are highly regarded for their stability in terms of pitch shift?

Many thanks

Max
Sosabba
Frequent Poster
Posts: 576
Joined: Wed Mar 29, 2006 12:00 am
Location: UK

Re: How stable are record decks in terms of tempo/pitch?

Postby Wonks » Wed Feb 07, 2018 3:06 pm

Direct drive turntables are better for pitch and stability than belt drive, but have a bit more motor noise as a result.

I'd say that if you can play a record on the deck and can't hear any obvious 'wow', then you'll be fine.

A friend of mine has just reinstalled his UK motor in his belt drive 1980's Rega Planar 3 (he took it to the US with him but hasn't used it in the 10 years or so he's been back until now), and that has very definite wow and flutter issues that he's trying to fix.

If you can play something with a sustained note or chord and don't notice any pitch variations, then you won't notice anything on your digitised copy.
User avatar
Wonks
Jedi Poster
Posts: 6084
Joined: Thu May 29, 2003 12:00 am
Location: Reading, UK
Now even grumpier than Ivan in his heyday.

Re: How stable are record decks in terms of tempo/pitch?

Postby Tim Gillett » Wed Feb 07, 2018 3:11 pm

Unless the original musicians were playing to click tracks, it would probably be moot anyway. No musician keeps perfect time.
Tim Gillett
Frequent Poster
Posts: 1585
Joined: Wed Jan 30, 2013 1:00 am
Location: Perth, Western Australia

Re: How stable are record decks in terms of tempo/pitch?

Postby ken long » Wed Feb 07, 2018 3:23 pm

Li-rocchi wrote:Hi all

Part of the plan will be to digitise all of my vinyl (around 600-700). But that got me to thinking how stable my decks are in terms of speed / tempo / pitch. When I did mix way back when I used to beat match, and the two records would always drift slightly and need constant tiny adjustments. I never did fully understand whether that was inherently a vinyl thing or just me not being that good at it! One of the attractions with vinyl would be more stability, but if I am playing an unstable recording of a digitised vinyl, then I guess I'd still be in the same boat.

You could invest in a Laser Tachometer. This model is useful:

https://goo.gl/jWrd6k

Attach a reflector to the platter, point the tachometer at it. It will display the RPM after a few revs.
User avatar
ken long
Frequent Poster (Level2)
Posts: 3278
Joined: Mon Jan 21, 2008 1:00 am
Location: The Orient, East London
I'm All Ears.

Re: How stable are record decks in terms of tempo/pitch?

Postby James Perrett » Wed Feb 07, 2018 3:27 pm

Tim Gillett wrote:Unless the original musicians were playing to click tracks, it would probably be moot anyway. No musician keeps perfect time.

But computers do - and I suspect that many of the records in question used computer sequencing as it was pretty common in dance music from the 1980's onwards.

Personally I wouldn't use exactly the same setup for transferring vinyl as you would for DJ'ing. You'll get much better results with a cartridge that has an elliptical stylus but you would need to reduce the tracking weight down to 2g or less to use it. You would also need to use an arm with suitably low friction - I'm pretty sure that a genuine Technics would be OK (as it was originally sold as a hifi turntable) but other DJ turntables may not like working at a low tracking weight.
User avatar
James Perrett
Moderator
Posts: 7532
Joined: Mon Sep 10, 2001 12:00 am
Location: The wilds of Hampshire
JRP Music - Audio Mastering and Restoration. JRP Music Facebook Page

Re: How stable are record decks in terms of tempo/pitch?

Postby Hugh Robjohns » Wed Feb 07, 2018 3:34 pm

There are lots of different aspects of this.

Short term pitch variations are usually referred to as wow and flutter. Wow is a slow speed pitch cycling effect most usually occurring as a result of an off-centre locating hole in the record, and there is no practical solution to that other than replacing the record with one that's been punched more accurately.

Flutter has a much higher rate, more like vibrato, and tends to be related to the motor drive mechanism. Belt drive record players can suffer from it when the belt is worn out, or the spindle or platter surfaces become contaminated, while direct-drive systems can suffer from it through the inherent 'cogging' action of the direct-drive motor. A heavier platter tends to reduce the audibility of flutter in both cases, but that obviously impedes the 'instant start' capability usually required in a DJ turntable.

When it comes to tempo and beat matching, the more critical speed control aspects are the absolute rotational speed of the platter (is it really 33.3333 or 45 rpm?) and the long-term drift in speed accuracy. In old school decks absolute speed is determined by the machining accuracy of the drive spindles and the frequency of the mains supply, but in most DJ decks a crystal-based oscillator is more commonly used to determine the motor speed. This approach also makes it easier to offset that speed up or down to facilitate beat matching etc, often via a slider or rotary control on the desk itself.

I've not used the Numark decks, only the Technics, but I'd have thought assuming both were well maintained there'd be little to choose between them in terms of speed accuracy and stability.

H
User avatar
Hugh Robjohns
Moderator
Posts: 21773
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound

Re: How stable are record decks in terms of tempo/pitch?

Postby Folderol » Wed Feb 07, 2018 5:14 pm

There is a method for dealing with wow caused by off-centre pressing I've used a number of times. If it's an LP (or doesn't have a large diameter punch out) it requires a deck with a removable centre spindle.

With that taken out you place the record as centrally as you can, then put a fairly heavy weight on it - enough to stop it sliding by itself, but not enough to cause drive problems. You then place the stylus as usual and watch carefully for drift. Once you get the timing, get a small bit of wood and just give the record a very gentle sideways tap. Keep doing that until the stylus tracks true. It takes a bit of practice!

Singles were always the worst, and after doing a few dozen you get quite good at it :)
User avatar
Folderol
Jedi Poster
Posts: 7060
Joined: Sat Nov 15, 2008 1:00 am
Location: Rochester, UK
Yes. I am that Linux nut.

Re: How stable are record decks in terms of tempo/pitch?

Postby Hugh Robjohns » Wed Feb 07, 2018 5:36 pm

Just one of the very, very, many, many technical problems and compromises associated with the vinyl record...

If anyone tried to design a 'high quality' audio medium like that today they'd be laughed off the stage... but try telling the hipster kids that! ;-)

H
User avatar
Hugh Robjohns
Moderator
Posts: 21773
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound

Re: How stable are record decks in terms of tempo/pitch?

Postby ef37a » Wed Feb 07, 2018 5:40 pm

I believe at their zenith the Techics direct drives had better specs than the cutting lathes!

All hi fi tables that I know of had a strobe cut in the platter but you cannot rely on the mains to be spot on 50Hz if you are going to be this fussy! An old dodge was to illuminate the strobe from a telly screen, 50Hz plus or minus buggerall! Do modern FSTV put out 50Hz light?

Dave.
ef37a
Jedi Poster
Posts: 9443
Joined: Mon May 29, 2006 12:00 am
Location: northampton uk

Re: How stable are record decks in terms of tempo/pitch?

Postby Folderol » Wed Feb 07, 2018 6:13 pm

That's just reminded me of something else.
I read about a proposal for the ultimate record player (sorry I've no idea where) that turned everything on it's head. Instead of rotating the record, a tracking system with lasers would be used to read and digitise the grove walls.

As well completely eliminating speed issues, the idea was it should be able interpolate the shape the walls were supposed to be taking into account playings on conventional players

I've no idea if such a device was ever actually made. I think this was sometime in the mid 1970s so if it was ever done I imaging it you would have cost so much you would have had to take of a mortgage on just the the deposit!
User avatar
Folderol
Jedi Poster
Posts: 7060
Joined: Sat Nov 15, 2008 1:00 am
Location: Rochester, UK
Yes. I am that Linux nut.

Re: How stable are record decks in terms of tempo/pitch?

Postby The Korff » Thu Feb 08, 2018 10:21 am

Yes, the laser-turntable idea pops up from time to time... They're usually outrageously expensive — and don't handle dust very well!
The Korff
Frequent Poster (Level2)
Posts: 2054
Joined: Fri Jan 08, 2010 12:28 pm
Location: The Wrong Precinct

Re: How stable are record decks in terms of tempo/pitch?

Postby Sam Spoons » Thu Feb 08, 2018 10:31 am

But if Dyson designed it........
User avatar
Sam Spoons
Jedi Poster
Posts: 7063
Joined: Thu Jan 23, 2003 1:00 am
Location: Manchester UK
Finally taking this recording lark seriously (and recording my Gypsy Jazz CD)........

Re: How stable are record decks in terms of tempo/pitch?

Postby Hugh Robjohns » Thu Feb 08, 2018 12:00 pm

ELP was the system I remember, and I think it is still available:

Image

http://elpj.com/

It is built to order and costs around $15k / £12k for the 'basic' model, and nearer $25k /£20k for the 'master' model. It's primarily aimed at sound libraries rather than hi-fi enthusiasts, so that records can be transcribed without further damage... but I don't know how good it is at coping with existing damage and dust.

H
User avatar
Hugh Robjohns
Moderator
Posts: 21773
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound

Re: How stable are record decks in terms of tempo/pitch?

Postby Sam Spoons » Thu Feb 08, 2018 12:38 pm

Do you think, if we sprayed a LP with silver paint a Video Disk player would play it :roll:

Image
User avatar
Sam Spoons
Jedi Poster
Posts: 7063
Joined: Thu Jan 23, 2003 1:00 am
Location: Manchester UK
Finally taking this recording lark seriously (and recording my Gypsy Jazz CD)........

Re: How stable are record decks in terms of tempo/pitch?

Postby Agharta » Thu Feb 08, 2018 12:47 pm

Sam Spoons wrote:Do you think, if we sprayed a LP with silver paint a Video Disk player would play it :roll:

Yes, but you'd need to use the correct shade of silver depending on the region compatibility of your player.
American players are compatible with 'Spaceman Silver' whereas UK versions support 'Royal Mint Silver'.
User avatar
Agharta
Frequent Poster (Level2)
Posts: 2834
Joined: Sat Oct 30, 2004 12:00 am

Re: How stable are record decks in terms of tempo/pitch?

Postby blinddrew » Thu Feb 08, 2018 1:40 pm

I always wondered how that worked. :)
User avatar
blinddrew
Jedi Poster
Posts: 5100
Joined: Sun Jul 05, 2015 12:00 am
Location: York
Ignore the post count, I have no idea what I'm doing...

Re: How stable are record decks in terms of tempo/pitch?

Postby Sam Spoons » Thu Feb 08, 2018 1:42 pm

No you're wrong, it's only David Bowie albums that need to be "Spaceman Silver", American region machines need "Detroit Chrome"
User avatar
Sam Spoons
Jedi Poster
Posts: 7063
Joined: Thu Jan 23, 2003 1:00 am
Location: Manchester UK
Finally taking this recording lark seriously (and recording my Gypsy Jazz CD)........

Re: How stable are record decks in terms of tempo/pitch?

Postby Agharta » Thu Feb 08, 2018 1:46 pm

Sam Spoons wrote:No you're wrong, it's only David Bowie albums that need to be "Spaceman Silver", American region machines need "Detroit Chrome"

Come on man, Bowie is region free, he swung both sides of the channel. ;)
User avatar
Agharta
Frequent Poster (Level2)
Posts: 2834
Joined: Sat Oct 30, 2004 12:00 am

Re: How stable are record decks in terms of tempo/pitch?

Postby Sam Spoons » Thu Feb 08, 2018 1:48 pm

Yeah, that's why "Spaceman Silver" is the only option, without it "In space no-one can hear you scream......."
User avatar
Sam Spoons
Jedi Poster
Posts: 7063
Joined: Thu Jan 23, 2003 1:00 am
Location: Manchester UK
Finally taking this recording lark seriously (and recording my Gypsy Jazz CD)........

Re: How stable are record decks in terms of tempo/pitch?

Postby ManFromGlass » Thu Feb 08, 2018 2:31 pm

that's why NASA invented dehydrated Tang flavoured lube - just add water and massage for a few seconds....
User avatar
ManFromGlass
Frequent Poster
Posts: 1471
Joined: Sun Jul 24, 2011 12:00 am
Location: In the woods in Canada
 

Next

Who is online

Users browsing this forum: No registered users