density of active particles on reel tapes?

bandorr · 20th March 2010

Hi I'll like to know what is density of active particles on reel-to-reel magnetic tapes per mm or cm.I need this for a project I'm involved.

Maybe i'm not asking the question in the right place(sorry for that if the case) also I realize that the exact number is probably closely guarded secret

, but I'm REALLY interested in this matter.

Thanks in advance.

Sigma · 20th March 2010

don't know the answer but do know that an "exact number" doesn't exist..because tape always has asperity issues..i'm sure there was a target density though

vernier · 20th March 2010

Billion particles per square inch, give or take.

Fletcher · 21st March 2010

About 20 years ago a friend who was the head of technical at a rather famous NY studio explained to me [during a rather extensive coke filled evening of conversations that were based around solving the problems of the world... and most coke binges seem to mutate toward] that at 30ips with the track width of an A-800 the "sample rate" was somewhere around 8meg [as the little particles of rust are charged "+" or "-" which is similar in nature to the "1"s and "0"s in the digital domain].

Now, where he got this number, I don't know. If the calculation was correct or not, I don't know... BUT, he was certainly one of THE most knowledgeable tech guys I'd ever met... and had an affinity for getting to the 'molecular level' of how and why things worked... so, on a leap of faith I thought I'd believe the statement as it seemed plausible to me.

20 years later [and knowing his proclivity for cocaine at the time], I almost wonder if he sat there with a microscope and counted the damn things.

Sigma · 21st March 2010

Quote:

Originally Posted by Fletcher

About 20 years ago a friend who was the head of technical at a rather famous NY studio explained to me [during a rather extensive coke filled evening of conversations that were based around solving the problems of the world... and most coke binges seem to mutate toward] that at 30ips with the track width of an A-800 the "sample rate" was somewhere around 8meg [as the little particles of rust are charged "+" or "-" which is similar in nature to the "1"s and "0"s in the digital domain].

Now, where he got this number, I don't know. If the calculation was correct or not, I don't know... BUT, he was certainly one of THE most knowledgeable tech guys I'd ever met... and had an affinity for getting to the 'molecular level' of how and why things worked... so, on a leap of faith I thought I'd believe the statement as it seemed plausible to me.

20 years later [and knowing his proclivity for cocaine at the time], I almost wonder if he sat there with a microscope and counted the damn things.

when we cleaned out fader buckets the question always was.."is that dander or cocaine" LOLZ

nosebleedaudio · 21st March 2010

The total thickness is .003"
The oxide a little over .0006"
I can not think of any reason why anyone needs to know this..
Unless you plan on man. your own tape...

bandorr · 21st March 2010

Thanks everyone for the responses.

Sigma, I don't need an "exact" number,rather an average estimation of the particles if this is possible.

Fletcher, thanks for the information and the story.I got the idea of the 8 meg samplerate,what i don't really understand (probably due to my very poor english )if he meant per second or per "sample" 8 meg.

nosebleed thanks very much for the info.I will try to do the math(not my strongest point at least)to extrapolate.No I don't plan to buy a tape machine but this info has became very important to me

Fletcher · 21st March 2010

8 million samples per second [based on "1" & "0" being equal to the "+" or "-" that each oxide particle is charged].

Again - take it with a grain of salt [obvious reasons]

bandorr · 21st March 2010

Quote:

Originally Posted by Fletcher

8 million samples per second [based on "1" & "0" being equal to the "+" or "-" that each oxide particle is charged].

Again - take it with a grain of salt [obvious reasons]

Thanks.If this even 50% true, it explain a lot.BTW i like your signature(that with the emotions).

bandorr · 6th April 2010

I just realized; I'm already magnitude times better the 8million samples(at least internally)

20th March 2010	#1
bandorr Gear addict Joined: Jan 2007 Location: romania Posts: 386 Thread Starter	density of active particles on reel tapes? Hi I'll like to know what is density of active particles on reel-to-reel magnetic tapes per mm or cm.I need this for a project I'm involved. Maybe i'm not asking the question in the right place(sorry for that if the case) also I realize that the exact number is probably closely guarded secret, but I'm REALLY interested in this matter. Thanks in advance. __________________ There are three myths in ITB mixing:The so called phase null test;All DAW sound the same;We are mixing audio First custom modified DAW( no... NOT the hardware)

20th March 2010	#2
Sigma Lives for gear Joined: May 2006 Location: phallicdelphia Posts: 4,618	don't know the answer but do know that an "exact number" doesn't exist..because tape always has asperity issues..i'm sure there was a target density though __________________ "The notes I handle no better than many pianists. But the pauses between the notes, ah, that is where the art resides." Artur Schnabel http://miketarsia.com http://www.myspace.com/miketarsia https://members.grammy365.com/users/mike-tarsia

21st March 2010	#4
Fletcher member no 666 Joined: Jun 2002 Location: Durham, NC Posts: 10,108	About 20 years ago a friend who was the head of technical at a rather famous NY studio explained to me [during a rather extensive coke filled evening of conversations that were based around solving the problems of the world... and most coke binges seem to mutate toward] that at 30ips with the track width of an A-800 the "sample rate" was somewhere around 8meg [as the little particles of rust are charged "+" or "-" which is similar in nature to the "1"s and "0"s in the digital domain]. Now, where he got this number, I don't know. If the calculation was correct or not, I don't know... BUT, he was certainly one of THE most knowledgeable tech guys I'd ever met... and had an affinity for getting to the 'molecular level' of how and why things worked... so, on a leap of faith I thought I'd believe the statement as it seemed plausible to me. 20 years later [and knowing his proclivity for cocaine at the time], I almost wonder if he sat there with a microscope and counted the damn things. __________________ CN Fletcher Professional Affiliations: R/E/P Professional Recording Engineer and Producer forums - serious hobbyists welcome SoundPure.com mwagener wrote on Sat, 11 September 2004 14:33 We are selling emotions, there are no emotions in a grid Roscoe Ambel once said: Pro-Tools is to audio what fluorescent is to light

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20th March 2010	#3
vernier Lives for gear Joined: Mar 2006 Posts: 6,130	Billion particles per square inch, give or take.

21st March 2010	#6
nosebleedaudio Lives for gear Joined: Jun 2005 Location: Birmingham, AL USA Posts: 3,700	The total thickness is .003" The oxide a little over .0006" I can not think of any reason why anyone needs to know this.. Unless you plan on man. your own tape...

6th April 2010	#10
bandorr Gear addict Joined: Jan 2007 Location: romania Posts: 386 Thread Starter	I just realized; I'm already magnitude times better the 8million samples(at least internally)