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I bought a few Maxell cassette tapes, a portable Sony cassette tapes recorder (with the possibility to record also from an external microphone: in my case, a jack connected to the PC) and - as already said - I have a male-to-male jack to connect the recorder to the line out of the PC.

I tried to record something (a few FLACs on Audacity) after having set the volume loud enough but not so much that it would make the recording sound distorded and, while it seems that the audio is correctly recorded, I can hear a lot of tape hiss. By a lot, I mean quite a lot more than the one I can hear in old tapes I have at home.

Are there any tricks (in Audacity or not) to reduce it? Thank you very much!

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    i gotta ask why ya got a cassette tape recorder instead of a digital one...? – Stephen Hazel Jan 23 '16 at 16:43
  • For fun, just trying to record a few old tapes ;) – lucia de finetti Jan 23 '16 at 16:44
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    Oh boy the line out on the PC is not a very good output for minimum noise. If you're using a basic tape deck and consumer level electronics and cheap, non-new cassettes, it will be very hard to achieve a low noise floor. That's why people still spend a lot of money for a Tascam 488 Mk II recorder because it makes analog cassette recording with low noise possible. You can do hours of research on minimizing tape hiss and there are lots of technical details. You might consider getting a decent audio interface also and make sure you have the proper cables. – Todd Wilcox Jan 23 '16 at 18:29
  • This question is a dupe of electronics.stackexchange.com/questions/213017/… – Simon B Jan 23 '16 at 22:30
  • Yes @Simon B, I asked there as well. Didn't know it was forbidden... – lucia de finetti Jan 23 '16 at 22:35
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Magnetic tape was one of the first formats that allowed folks to easily record speech or music at home. Unfortunately one of the biggest problems with cassette tapes using the magnetic tape format was their propensity to produce prominent hiss.

Here is a quote from Wikipedia article on "Tape Hiss":

Tape hiss is the high frequency noise present on analogue magnetic tape recordings caused by the size of the magnetic particles used to make the tape.

In the 1960's Dolby Laboratories invented a complex system for reducing this hiss which allowed the cassette tape medium to render tolerable (if not quite hi fidelity) reproductions of music. Thanks to Dolby, the cassette tape became the most popular medium for car stereos until the CD player was released. It's a rather sophisticated technology that must be used during the recording process and played back on a machine with the proper decoder. Many cassette tape machines meant to play music cassettes - will have either Dolby B or Dolby C or both settings as one of the controls available. These settings will only work on tapes that were recorded using the corresponding type of Dolby Noise Reduction (NR). From the Wikipedia Article on "Dolby Noise Reduction System":

all the Dolby variants work by companding, or compressing the dynamic range of the sound during recording and expanding it during playback.

The reason you don't hear the same amount of hiss on your old music cassette tapes may very well be because they were recorded using a combination of noise reduction (read hiss reduction) techniques including Dolby NR.

Audacity is a product of the modern digital age where new technology has made cassette tapes basically obsolete. Many folks use Audacity to transfer their old music cassettes to a digital format so they can preserve them for posterity or play them on their mp3 playback device. Unfortunately, the built in noise reduction effects in Audacity are geared towards reducing the hiss when recording TO Audacity from a cassette and not recording FROM Audacity to a cassette.

You might be able to reduce the hiss some by playing around with the effects in Audacity starting with the noise removal effect and also try equalization and high pass filter. Expand the wave form envelope as much as you can and focus on the higher frequencies. You might try recording the tape hiss back to a digital format so you can open the file with Audacity and see what frequencies the hiss lies in so you will know where to focus your tinkering.

Just be aware than the Dolby system was very complex and sophisticated which is why they were able to patent it and no other company offered a competing technology. Any success you achieve reducing hiss with the audacity controls will also reduce some of the musical fidelity. The developers and ongoing development of technologies such as Audacity, never envisioned producing an audio file for the specific purpose of transferring said file to magnetic tape.

One other thing that I have discovered, is that one of my older stereo digital voice recorders generates noise artifacts when I try to input from my computer into the mic in jack using a TRS connector while one of my newest stereo digital voice recorders does not. So there is a possibility that some of the problem could be in the mic input jack as well. Either way, it might be worth a shot to try playing back your digital recording through the best speakers available and record to your cassette recorder using the built in mic and see if the results have less objectionable noise.

Good luck.

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    In addition to noise reduction companding, using the fastest possible tape speed and the correct bias settings will help. Recorder bias should be matched to the tape formulation for minimum hiss. – Todd Wilcox Jan 23 '16 at 18:25
  • I don't see any versions of Dolby noise reduction newer than 1989 in en.wikipedia.org/wiki/Dolby_noise-reduction_system , so it should be out of patent. Thus it should be legal to replicate a version with a digital filter, if the specifications are clear enough. – Steve Feb 14 '18 at 7:02
  • Afterthought: the above could be read as legal advice. But I'm not a patent lawyer, I'm not your lawyer, and I'm not a lawyer at all. So don't treat it as legal advice. – Steve Feb 14 '18 at 7:35
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just gotta ask, the tape hiss might be because your recording using a DC Bias Recorder, and the recorder you have isn't also stereo, i bought a stereo recorder from 1995, a Sony one which also has a Japanese counterpart, when i knew it was recoridng on DC Bias, i quickly did some estimations on how to emphasize the loud portions of the tape using an equalizer, but in my case this isn't enough, so i bought a Sony Boombox instead, which surprising had AC Bias which improved the recording nicely, one thing is also apparwent is more tape hiss than when i recorded on my sony walkman, but one thing i noticed if you recorded it near the peak level the hiss goes away, the one thing also is that when the sound is correctly recorded theres slight hiss, might be the Motor of the player isn't connected to a ground loop like what most tape decks have, so if you want a really hifi recording on a tape 1 normal bias tape is you need a hifi deck or a reliable boombox to use that has AC Bias, you'll know the sound of it once you've listened the highs are like comparable to a CD but with a more warmer vibe to it, you can also tweak the azimuth adjustement (the screw on top of the tape head) on it to increase trebl which i did on my walkman to sound the best on my tapes, https://en.wikipedia.org/wiki/Tape_bias, http://www.endino.com/archive/cassettes.html

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Audacity has hiss/noise removal built in. Here is a simple tutorial video which shows how to use it:

  • Thanks @Tekkerue but that's useful when performing the opposite process (from cassette tape to digital)! – lucia de finetti Jan 23 '16 at 17:49
  • So you're using Audacity and going from that to the tape recorder?...I guess I'm not understanding what you're trying to do then. I thought you were trying to record old tapes to digital and remove the tape hiss. Going from digital to tape will only degrade the quality and add hiss/noise (as you experienced). In this case Audacity is not the recording platform so about the only thing you can do is record as loud as possible on the tape player (just below clipping) so that the audio level is well above the noise floor. If the tape recorder has Dolby noise reduction settings try using that also. – Tekkerue Jan 23 '16 at 18:16
  • The problem is one of signal levels. He's dropping the signal level out of Audacity to prevent clipping of the mic input on his cassette recorder. This leaves the sound card noise un-attenuated. I've given a solution in his duplicate post on EE.SE linked in the comments under the OP. – Transistor Jan 24 '16 at 10:28
  • Oh, I see...originally I thought he was going from tape to digital, so I missed that he was using the mic input on the tape deck from the computer's line out...I'm still not sure what his purpose for doing this is though. But in this case, the RCA inputs should be used on the tape deck. An adapter with a stereo 1/8" to two RCA connectors will allow the line output from the computer to plug into the tape deck, that keeps everything line level and that's better than trying to attenuate the signal down to mic level. And it will allow for recording stereo sources too since mic inputs are mono. – Tekkerue Jan 24 '16 at 10:44
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It sounds like you're using a MIC input to record from a LINE out. That's not ideal, as microphone inputs have a high gain. A LINE input to the cassette recorded would be better if it has one.

Check that the bias setting of the cassette recorder matches that of the tape. If it doesn't have a control, then it was probably only designed to work with ferric oxide tapes, not chrome or metal ones.

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You are probably feeding too little gain into the analog recorder. The best thing about analog tape is the dynamics-compressed sound and distortion it produces when you overload/saturate it.

If you are used to digital recording, you think of 0 dB being the absolute ceiling, but in analog recording, 0 dB and above is where it gets interesting.

So I recommend you increase the volume of the source and invite the distortion. Higher gain will minimize the tape hiss and distortion will cover the tape hiss.

After all, if you want a clean recording, you wouldn’t be using the analog tape in the first place. I would say in for a penny, in for a pound. Crank it.

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Your problem is likely the mic-in connection to the tape recorder: to have the right level for that, you'll likely need to attenuate your sound card output a lot just to have it reamplified again in the mic preamp.

If that thing does not have a proper line input for recording, chances are that you could create one by plugging into the right place in its circuitry. An electronics tinkerer should likely be able to do that if stuff is obvious enough. This would help with the noise floor by removing one particularly noise-prone stage from the recording pipeline.

Portable tape recorders (as opposed to minidisc players where even the portables with a recording function tend to be quite ok) were not usually intended for creating quality recordings. It's more like being able to use it as a dictation device. Preparing the tapes for portable listening is usually left to the realm of good tape recorders. So there is a good chance that your setup is not viable for perfect solutions.

Of course you know that already. But there is a chance that some cutting and soldering will at least make it better if there is nothing akin to a line input to be gained by other means.

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