Tape to CD project

[madmax]

I have some old cassette tapes to convert to digital for an upcoming anniversary of a live performance and thought I would share the process and maybe get some good ideas. I would have given up 20 hours ago but I really really really want to make this work. The recording is very dear to me.

For most things I would just load the cassette player and copy onto my CD recorder but there are a few problems with this conversion.

1. The tape is 30 years old. It was a cheap Scotch brand tape, normal bias, a very cheap product at the time.
2. The recording was made on an old $20 mono tape recorder from the built in microphone.

I put the tape in the machine, fired it up and the first thing it did was pull out. I fixed that, put it back in and it broke. Fixing the break I noticed particles of the tape were coming off in flakes. OK, so at this point I know there is not much chance. I put it back together, cross my fingers and get it to play. With the recording level quickly set I proceed to get a one to one copy of the tape on CD. Yea, it broke a few more times but finally at least I have whatever is there preserved on a CD, however unlistenable it may be.

The sound quality? None. It has very big peaks in different midrange and treble regions, no detectable bass below 80hz, some huge hump in the lower midbass and the quality varies between the left and right channel quite a bit. The sound is very compressed on loud passages and thin on quiet ones. I don't think it could be any worse. It is almost totally trashed in this form.

As an audiophile I'm of the opinion that capturing the original as faithfully as possible is of the most importance but have to face the facts on this one, no one could bear to listen as is. Besides, I do have the original on a CD and will hold onto it.

Now for the fun part, trying to enhance and bring it up to some level of listenability. I've decided I'm going to take every liberty to make it better and currently have it running through a lot of processors. The signal path is listed below from input to output.

Theta transport
AudioNote tube DAC
AudioControl Epicenter (Synthesizes bass based on higher frequencies)
BBE Sonic Maximizer (Adds definition to the highs/lows)
Alesis 30 band EQ (To smooth out the response curve)
Spatial Seperator (Recreates a little life in the recording)
Audible Illusions tube preamp (To control the output of this mess)
Sony CD recorder with SBM

So far I've started from top to bottom of the list eliminating one problem at a time. I'm playing the output into my Manley Reference mono-blocks and monitoring the sound through the SDA SRS. Once I get something that sounds good I feed into the CD recorder and make a disc. I then play the disc through my normal system to see if I'm close. When I think it sounds OK I try on a few other systems including my HD-600 Sennheisers.

I've gone through this process a few times and although I'm almost there I can't seem to give up and say this is the end product. I keep thinking about trying a digital route but right now I'm not sure what I want to do.

Any thoughts on a digital means of manipulating the sound would be appreciated. Right now I have it sounding somewhat alive and exciting but it is still missing the mark. My biggest problems are on the high end. I can cut tape hiss pretty easily without compromising the sound but things like cymbals and some of the voice is still very rough and high output. I can bring them down to something reasonable but I loose all the excitement of the recording.

Its a fun project but I'll be very glad when its done. :D

madmax

[madmax]

Try Audacity. It's easy and free.

I downloaded Audacity and played with one track. I used the normalization function then a noise removal function on a track where I had already done everything else at home. It seems to sound much more uniform now on my PC. I'll take it home and see what it sounds like there. I'm thinking it would probably be a good thing to start with the original non-modified copy instead of the one I have here.

Thanks!
madmax

[madmax]

I've been playing with the Audacity software all evening. I went through each effect and there are a lot of cool things you could do if you want to be creative. It looks pretty good for LP's especially if you wanted to clean them up a bit or use the various equalization curves for different vintage recordings.

For what I'm doing it is very good at letting you fade in, tie songs together and other such presentation type things but it is not helping much with the sound problems. Fixing one very small problem tends to cause way more problems elsewhere. Not the fault of the software, I just need to do too much and don't have much to work with sound wise.

I think I will use it to make the presentation better but leave most of the sound enhancement to the analog equipment.

Actually, the best function it has for my application is I can select an area and do a frequency analysis. I've printed out many plots and will check my equalizer settings against the avereages. I can see the overall characteristics of the recorder which was used and correct for them. I've already done it by ear and believe it or not my current EQ curve is VERY similar except for a few sections. This will help me dial it in a little better!

madmax

[madmax]

It was 2 AM this morning when it hit me. With Audacity I have the ability to create delays, reverse polarity, create multiple tracks then mix them back to two tracks.

I have all the tools necessary to create an SDA like sound!!!

This should get fun now...

madmax

[madmax]

I was able to re-create an SDA effect!!! I took a song which I know very well on my SDA's, did the conversion and checked it out on my non-SDA computer system.

The conversion went like this:
*copy and paste the stereo track
*unhook the stereo tracks from each other
*inverted polarities of the the new left and right track (made + be - and - be +)
*swapped new inverted L and R tracks (made L be R and R be Left)
*ran a low pass filter on inverted L and R tracks (900HZ)
*ran a high pass filter on inverted L and R tracks (400HZ)
*removed .0008 seconds off the original L and R tracks
*played all together with all faders and level set at 0dB

If anyone does this don't tie the two new tracks back to a stereo track because L and R will change back to their original designations and will no longer be swapped, thus, no SDA.

Makes for a decent SDA but could probably be improved using different amounts of delay (how much you cut off the original L&R) and different filter points.

This won't help my original project much but sure was a lot of fun!

madmax

[ben62670]

Thats cool. I spent a lot of time trying to do that with an electronic crossover, and when I was about to set off, and do it I realized all my design was a Carver Holography converter!

[madmax]

I was pretty surprised how interrelated the delay, low and high pass set points were. You could spend the rest of your life trying to optimize... :)
madmax