Problem with audio cassette tape frequency range

[shon3i]

I searched forum and not find nothing simmilar.

I have some original audio cassettes which i want to digitalize (burn to CD)

My problem is when i record this files using Adobe Audition i get file which have big cutoff @ 12-14khz. On my cassette deck player that different is not nocable, but on my computer comapring that files to original ( ihave some songs but not all and i can't find it on any p2p network) 44khz files there is big differents.

http://img489.imageshack.us/img489/7803/untitledct2.th.jpg (http://img489.imageshack.us/my.php?image=untitledct2.jpg)

So how i can reconstruct/modulate/add harmonics Higher Frequencies up to 18-22khz aginst low-mid frequencies. Which filter i need to use/vts plugin or other program.

Thanks very much.
Shon3i

[ursamtl]

I searched forum and not find nothing simmilar.

I have some original audio cassettes which i want to digitalize (burn to CD)

My problem is when i record this files using Adobe Audition i get file which have big cutoff @ 12-14khz. On my cassette deck player that different is not nocable, but on my computer comapring that files to original ( ihave some songs but not all and i can't find it on any p2p network) 44khz files there is big differents.

http://img489.imageshack.us/img489/7803/untitledct2.th.jpg (http://img489.imageshack.us/my.php?image=untitledct2.jpg)

So how i can reconstruct/modulate/add harmonics Higher Frequencies up to 18-22khz aginst low-mid frequencies. Which filter i need to use/vts plugin or other program.

Thanks very much.
Shon3i

Are you saying that you notice a difference in the sound between your cassette deck playback and playback from your computer once it's digitized? If so, then there may be a problem with your digitization since simply having the audio on your PC shouldn't make a difference.

On the other hand, if it's just a matter of visually noticing that the frequencies above 14kHz are missing, then I wouldn't worry about it. I've seen digital recordings done at 24/192 from a high-end turntable that have frequencies running well up into the 50-60kHz range and it certainly looks cool but no human can hear that high. Actually, many humans hear very little above 14khz. There are some who do, especially younger people, but the difference should be very subtle, the very tops of cymbals, etc.

If you really feel the need to generate some frequencies, there are various "exciter" or "enhancer" plugins around, a couple of them are freeware. Check www.kvraudio.com and look around for them. Don't forget that these are basically adding high-frequency distortion so don't add too much. It's also a good idea to leave the material for a couple of days after treating it and come back to listen to it with fresh ears. This is because when we are working with changes to frequencies, our hearing tends to become less sensitive to the changes we make. I've EQed stuff at times and thought it sounded brilliant only to come back later and discover it was much too bright! The same thing happens when one is applying effects like reverb. What sounds good at the moment sounds much too extreme a week later!

Good luck.

Regards,
Steve.

[scharfis_brain]

how were these files recorded nto the PC? which setting were used?

it looks a lot like 32kHz sampling, cause there is a hard frequency cutoff at 16 kHz. Under normal conditions the range of 16 to 22 khz would contain some noise at least, but in your image everything is black above 16 kHz.

Also try to use some other sampling frequenciesduring recording like 48 kHz or 96 kHz as well es other bitdephts like 24 or 32 bit.
Downsampling to 44.1 kHz afterwards can always be done.

[shon3i]

how were these files recorded nto the PC? which setting were used?
I record in Audobe Audition with 44khz, 16bits, stereo.

Also try to use some other sampling frequenciesduring recording like 48 kHz or 96 kHz as well es other bitdephts like 24 or 32 bit.
Downsampling to 44.1 kHz afterwards can always be done.Nothing's changed, because looks simply that cassette can't have biger than 11-14khz, so i need something to add freqencies upper to emulate 44khz

Are you saying that you notice a difference in the sound between your cassette deck playback and playback from your computer once it's digitized? If so, then there may be a problem with your digitization since simply having the audio on your PC shouldn't make a difference.
Actualy no, on this cassete i have some songs (not all) which i found on internet, and when i record from cassette to pc and comare with that internet song , the quality is so different like cassette have only 22-32khz instead 44khz, like cassette can't produce nothing upper than 11-14khz per channel, I tryed with many stereo's and other friend's decks, aslo with many other cassettes.

Here is samples (http://www.mytempdir.com/917790), please download and compare it.


If you really feel the need to generate some frequencies, there are various "exciter" or "enhancer" plugins around, a couple of them are freeware. Check www.kvraudio.com and look around for them. Don't forget that these are basically adding high-frequency distortion so don't add too much. It's also a good idea to leave the material for a couple of days after treating it and come back to listen to it with fresh ears. This is because when we are working with changes to frequencies, our hearing tends to become less sensitive to the changes we make. I've EQed stuff at times and thought it sounded brilliant only to come back later and discover it was much too bright! The same thing happens when one is applying effects like reverb. What sounds good at the moment sounds much too extreme a week later!
Thanks, i am now go to try this.

[scharfis_brain]

Look for frequency response in this article:
http://en.wikipedia.org/wiki/Cassette_deck

[shon3i]

Look for frequency response in this article:
http://en.wikipedia.org/wiki/Cassette_deck
wiki says that response is

The best home decks could achieve 20 Hz-20 kHz Probably High Fidelity

and

Average equipement achieves 30 Hz-15 kHz frequency response Probably Low-Fidelity

So probably i have second. Any suggestion with filtering to get not like original but simmilar

[shon3i]

I tryed two top rated exciters and enhancers, one is iZotope Ozone 3 vts, which aslo do a great master job, but i can't make high frequencies to sound very remarkable. Second is Spectralive, his add some frequencies up to 20khz but most of this are big distorsions, noise, very bad, which can't be reduced.

So what i can do with this, aslo Here (http://www.mytempdir.com/917790) is samples

I aslo find this http://www.spiritdsp.com/app.html. his app can reconstruct up to 18khz, aslo can be useful to restore bad mp3 compression, but not free

[tedgo]

You may not reach your destination with that kind of tools...
Your cassette sample doesn't only sound airless but noisy and with audible flutter too!

It may be a hint of:

1.) Dirty tape-heads.
Solution: Try to clean them with isopropylalcohol or at least with a cleaning cassette

2.) The tape-heads are magnetized.
Solution: Buy a demagnetizing cassette

3.) The azimuth of the tape-head is incorrect.
Solution: Try to adjust the azimuth by gentle screwing the left screw of the tape-head as long as the high frequencies reaches their top. But you will have to do it with every cassette you'll try to record to your pc...

4.) The cassette is very old or recorded on a low-fi tape deck
Solution: None, except the tools are mentioned by the other users...
I would recommend the "Band extrapolation" in NeroWaveEditor. It does a good job. But you will have to reduce the noise with a noise reduction too (also available in NeroWaveEditor)

The solution of 1.) will also reduce the flutter, but very less...
Good way to reduce flutter is to reel the whole cassette to the end and back to the beginning before playback.

(Sorry for the bad english, i'm sick since a few month and tired caused by medicaments...)

[shon3i]

First thanks for you answers, get rest, and be well

1.) I cleaned few times, i noticable little changes, because my deck stay long time without function, because CD player are replace default source

2.) I haved tape long time ago, i founded, and try demagnetize head. But i thnink that tape is not demagnetize beacuse is ten year old. Did i need to by a new tape.

3.) I do that and this is maximum, first time when i record, recording newer reach 11khz, now i up to 15khz. This is maximum

4.) I have many cassettes, and i have some when i ajust head with screw, his can't reach 10khz and that is probably recorded on Lo-fi. So i think that this cassette is not lo-fi recorded, beacuse i have some cassette from 2001 year, and is aslo up to 14-15khz

Thanks for you suggestion for Band extrapolation, i will give try. Can you filter my sample for me best as you can, to saw what i doing wrong in filtering.

Many times tanks you, and see ya.

(you aslo sorry for the bad english)

[tedgo]

By cleaning the tape-heads don't forget to clean the capstan(s) too (will reduce flutter)!

Have you tried it with alcohol or only with a cleaning cassette? Alcohol is a much better choice! The cleaning cassettes are often leaving their own dust on the heads...

The older a tape deck, the more magnetized are the heads!
Everytime a cassette is played on it the tape-heads are a little more magnetized. You should demagnetize the heads every 20 cassettes at the latest.
Magnetized heads will ERASE high frequencies from your tapes!

Your cassettes maybe all recorded on low-fi...
I don't know the tape-deck you recorded them.
Most reel to reel tape decks and nearly all tape decks integrated in popular mini- or midi-systems are "low-fi".
They often achieve only frequencies up to 15kHz in recording.
Single tape decks once bought at 200 € and above achieved frequencies in the 18-22kHz range (with metal band, 17-20kHz with chrome).

Are the recordings are made with dolby nr?
You should play them with the correct dolby setting (b, c or s if available) used during recording.
Never play non-nr-tapes with any kind of nr! It will reduce the high frequencies!
But i often played older cassettes recorded with dolby b without nr to record them to pc to achieve more high frequencies. But it is very difficult and needs good equipment to reduce the noise digitally...

Another trick to get more high frequencies without adding too much noise:
Change the playback bias by playing 'chrome' or 'metal' tapes as 'normal' tapes!
To do so, close the openings on the top of the cassette with adhesive tape or set your tape deck manually to 'normal' (possible only on very old tape decks).
Some tape-decks used this trick with the so-called 'play trim' (invented by yamaha, used by yamaha and nad). 'Play trim' manually sets the playback bias to restore lost high frequencies on playback.

Btw. Its not possible to filter your sample in any good way.
Too much flutter, noise and too less high frequencies.
And you may not reproduce the settings i would take because i use an expensive software to "clean-up" older recordings (Diamond Cut 6) after "restoring" lost high frequencies with NeroWaveEditors Band Extrapolation...

[shon3i]

By cleaning the tape-heads don't forget to clean the capstan(s) too (will reduce flutter)!Yes i am

Have you tried it with alcohol or only with a cleaning cassette? With both, and first with alocohol than with type, but like i said type is too old and maybe don't have anymore effect to demagnetize, so i will try to clean again with alcohol

Magnetized heads will ERASE high frequencies from your tapes! Hmm, very interesting, i newer know that. Thanks for lesson

Your cassettes maybe all recorded on low-fi...
I don't know the tape-deck you recorded them.I not record them, my father is buy this cassete in '86-'88, when use this this deck with other equipment (Tehnics, with seperate deck, tuner, turntable, ampfiler, very good stereo, and very expensive, but maybe is old ). Cassette is original and have very good singles of Modern Talking, Murray Head (sample from test file) and other singers from that time, i founded all singles (on p2p network) except one (the song exist but singer is different and whole song sound is totality different). So i only want copy that song how much better is possible.

You should play them with the correct dolby setting (b, c or s if available) used during recording.I have one Dolby switch, so when i press it i lose more higer frequencyes.

[tedgo]

'Cleaning cassettes' and 'demagnetizing cassettes' are not the same!
Cleaning cassettes have a white band to 'sand' the tape heads.
Demagnetizing cassettes have a moving magnet to demagnetize the tape heads.

Original cassettes from the 80s up to now are all made with dolby b hx pro.
If you haven't enabled it during playback the tape will have much more noise (could explain your noisy sample).

Technics tape decks from the 80s are known as badly adjusted (bias, dolby level and azimuth).
Original tapes are often too airless. Own recordings made on it are often too high on other decks.
To adjust the internal bias and dolby level you would have to open the tape deck. Not recommended for unexperienced users...
To adjust the azimuth read my first posting.

EDIT:
P2P Network?
I hope its allowed in your location to download copyright material from it...
If not, you should try to get the songs from a legal musicstore and pay for them.
Sound quality of the bought songs is not cd-like but acceptable.

[shon3i]

'Cleaning cassettes" and "demagnetizing cassettes" are not the same!
Cleaning cassettes have a white band to "sand" the tape heads.
Demagnetizing cassettes have a moving magnet to demagnetize the tape heads.I have only demagnetizing cassette, so i must clean with alcohol then (which i do one time, but i will do again). Right?

(bias, dolby level and azimuth)Bias i big almost 1-2% in Adobe Audition settings

To adjust the azimuth read my first postingI adjust it and with this settings i get best result with max 15khz, first azimuth read gives me 11khz. Thanks for helping me.

[tedgo]

If you now gets 15kHz, maybe there is nothing more possible with original cassettes.
Old recordings automatically lose high frequencies because the band layers are magnetizing mutually. Cassettes are not a good medium for storage...

[shon3i]

If you now gets 15kHz, maybe there is nothing more possible with original cassettes.
Old recordings automatically lose high frequencies because the band layers are magnetizing mutually. Cassettes are not a good medium for storage...
OK, thanks very much for answers.

[pandy]

If you can try to sample with sampling frequency high as you can ie if your hardware suppoert 96ksps use a 96ksps then downsample in digital domain to the requested frequency ie 44.1ksps for CD Audio.
Always You can try multpiple records added together give in result lower noise level (noise are uncorelated and should be averaged)
Some expander SBR is present on the ffdshow - try to use ffdshow to SBR. Beware - ffdshow SBR working only on the 44.1ksps.
Use a floats as main format, try to do denoise (carefully!)

[aicha]

how about when using nakamichi tape deck (dragon series), that has automatic azimuth correction (http://en.wikipedia.org/wiki/Nakamichi).

[shon3i]

how about when using nakamichi tape deck (dragon series), that has automatic azimuth correction (http://en.wikipedia.org/wiki/Nakamichi).
Sounds good, but where to find it and how many cost?

[tedgo]

Nakamichi Dragon was introduced 1983 as the best tape deck ever, at least for playback caused by its NAAC (Nakamichi Auto Azimuth Control) technology.
It was only available up to the early 90s. I don't think that you will find a good second hand exemplar in an excellent working order below 750 €...

EDIT:
If you have to record more than one cassette to your pc the nakamichi dr-1 could be an alternative. It is manual playback azimuth adjustable. But all nakamichi tape decks will be very expensive, because they are real 'collector's items'...

[aicha]

i'm still searching this "dragon" too, because jakarta-indonesia have "booming" to back-up cassette. i found "dragon 3 - DR-3" at the second market with cost under us$150, but this deck have only 2-head, single capstan and without auto azimuth correction. this is detail of "dragon" http://www.vintagecassette.com/Nakamichi/Dragon and DR-3 http://www.vintagecassette.com/Nakamichi/DR-3

[tedgo]

'DR-3' is completely different from 'Dragon'!
Before i would buy a nakamichi DR-3 i would look for a newer and better tape deck. Because without NAAC or manual adjustment the nakamichi's are normal tape decks like all others...

Good and inexpensive second hand tape decks for recording and playback are:
Akai GX-75, GX-95 (indestructible glass-ferrit tape heads)
Pioneer CT-93, CT-95, CT-S 820S, CT-S 920S (but all only with a new drive belt...)
Sony TC-K 808ES, KA 6ES

[shon3i]

excellent working order below 750 €...
Uff, LOL.

If you have to record more than one cassette to your pc the nakamichi dr-1 could be an alternative.To be honest, i only need to copy one song, which i can't find on internet, because is some studio mix.

[SeeMoreDigital]

If you have a PC card that can capture digital audio streams (via an optical or digital input), you could invest a few quid an buy an "analogue to digital" converter.... Like this: -

http://www.lektropacks.co.uk/view_item.php?product=95&&category=21

http://www.maplin.co.uk/Search.aspx?criteria=QQ82D&doy=14m9&source=15

Both are the same device from different suppliers (very different prices). I use one to connect my VCR to my DSS amp...


Cheers

[shon3i]

If you have a PC card that can capture digital audio streams (via an optical or digital input), I only have SP/DIF output. Aslo this can't help me beacuse i have only 15khz in input signal, or this decoder can reconstruct lost frequencyes or add some frequency harmonics ?

[tedgo]

It wouldn't help you to record cassettes through an analogue to digital converter. It only converts the analogue cassette signal to digital signal prior to recording to pc.
Its unnecessary and doesn't solve your problem, although such converters often give a bit better quality than the
standard analogue input and its analogue to digital converter of your soundcard.

EDIT:
But if you want to edit the recorded songs (with denoiser, band extrapolation or whatever) you should set your soundcard to the highest possible bitdepth and resolution. I prefer to record with 88,2kHz and 32bit floating-point.