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Some days ago, a friend of mine visited me with a Revox A700 Tape recorder to do some listening comparisons.
To preserve these auditory impressions, we played a playlist from Roon, recorded the signal with the tape recorder, and simultaneously digitized the tape monitor output.
This was the recoding chain:
1.
2.
At the same time, we listened via the ADI 2/4 pro DAC part to what got recorded. This was the playback path:
The recorded sound was suprisingly soft, with gentler transients – particularly noticeable with drums – but seemingly without any significant loss of high frequencies. The listening experience was more "pleasant", as the transients, with all their detail, weren't as prominent. I personally enjoy a transparent system and hearing details, but for others, listening to a transparent system can often be too tiring because the details must be processed mentally! Overall, the tape recording wasn't that bad at all; it was more relaxed and softer. Perhaps better suited for a cozy evening with a glass of wine
We often hear that there are music lovers who prefer the analog sound of vinyl. It was only then that we realized that until the 1990s, everything we find on LP was recorded using a tape machine. So, what you're hearing isn't the analog sound of the LP, but rather the sound of the tape
To verify that another guy brought along two direct-cut LPs to our session, which were recorded without the tape in-between, and they didn't sound nearly as “beautifully” analog as the tape recorded tracks.
I wanted to find out what’s about this tape sound. I also played around with some VST tape recorder plugins but was not convinced. Next, I found this Master Thesis https://curdt.home.hdm-stuttgart.de/PDF/Muetsch_Masterthesis.pdf with a lot of information regarding audio recording. Best input for me (as an engineer) was a set of measurements the guy took with a Studer B67. Here a copy of this diagram from the thesis.
I now know that tape recorders are calibrated for a linear frequency response at a level of -20dB (red curve at -38dBFS). As the level increases, tape saturation sets in at the high frequencies. This reduces the output signal in the high frequencies. At 0dB (green curve -18dBFS), the high-frequency roll-off is already visible above 10kHz, which, at higher recording levels - when the tape saturates even more - develops into a significant roll-off, starting as low as 2kHz.
This is dynamic compression behavior which – due to its non-linearity – also generates many harmonic distortions. Fortunately, since only the high frequencies got compressed, these are mostly outside our perception range.
I've been experimenting for a while now to figure out what creates that “beautiful” vintage sound. I even bought a used tube amplifier you can see at the fotos above. With it, I heard some distortion at higher volumes and more noise than with my NCx500 power amp. But it wasn't that often-praised, smooth vintage sound! And no, I haven't taken any measurements on the tube amplifier since I almost never use it anyway. It's just an eye-catcher for visitors
Now I know that the tape recorder creates the so often praised "beautiful" vintage sound which is on most LPs before 1990.
I'm happy that I've finally solved this mystery for myself.
What I'm still missing is a DSP plugin in Roon that recreates the curves I showed here so I can finally switch to vintage sound with my transparent system. Unfortunately, I'm afraid we'll have to wait until Judgment Day for that.
I am interested to know if you have ever dealt with this topic and what your findings are.
Best DrCWO
To preserve these auditory impressions, we played a playlist from Roon, recorded the signal with the tape recorder, and simultaneously digitized the tape monitor output.
This was the recoding chain:
1.
Roon --> rooExtend-Box --> ADI-2 Pro (DAC) --> Revox A700 Record in2.
Revox A700 monitor out --> ADI 2/4 Pro (ADC) --> rooExtend-Box (rooPlay recording 24/96 FLAC on USB memory stick).At the same time, we listened via the ADI 2/4 pro DAC part to what got recorded. This was the playback path:
rooExtend-Box (rooPlay as source) --> Roon --> FIR for Room Coorection and XO --> ADI 2/4 Pro (DAC) --> NCx500 AMP plus two Woofers.The recorded sound was suprisingly soft, with gentler transients – particularly noticeable with drums – but seemingly without any significant loss of high frequencies. The listening experience was more "pleasant", as the transients, with all their detail, weren't as prominent. I personally enjoy a transparent system and hearing details, but for others, listening to a transparent system can often be too tiring because the details must be processed mentally! Overall, the tape recording wasn't that bad at all; it was more relaxed and softer. Perhaps better suited for a cozy evening with a glass of wine
We often hear that there are music lovers who prefer the analog sound of vinyl. It was only then that we realized that until the 1990s, everything we find on LP was recorded using a tape machine. So, what you're hearing isn't the analog sound of the LP, but rather the sound of the tape
To verify that another guy brought along two direct-cut LPs to our session, which were recorded without the tape in-between, and they didn't sound nearly as “beautifully” analog as the tape recorded tracks.
I wanted to find out what’s about this tape sound. I also played around with some VST tape recorder plugins but was not convinced. Next, I found this Master Thesis https://curdt.home.hdm-stuttgart.de/PDF/Muetsch_Masterthesis.pdf with a lot of information regarding audio recording. Best input for me (as an engineer) was a set of measurements the guy took with a Studer B67. Here a copy of this diagram from the thesis.
I now know that tape recorders are calibrated for a linear frequency response at a level of -20dB (red curve at -38dBFS). As the level increases, tape saturation sets in at the high frequencies. This reduces the output signal in the high frequencies. At 0dB (green curve -18dBFS), the high-frequency roll-off is already visible above 10kHz, which, at higher recording levels - when the tape saturates even more - develops into a significant roll-off, starting as low as 2kHz.
This is dynamic compression behavior which – due to its non-linearity – also generates many harmonic distortions. Fortunately, since only the high frequencies got compressed, these are mostly outside our perception range.
I've been experimenting for a while now to figure out what creates that “beautiful” vintage sound. I even bought a used tube amplifier you can see at the fotos above. With it, I heard some distortion at higher volumes and more noise than with my NCx500 power amp. But it wasn't that often-praised, smooth vintage sound! And no, I haven't taken any measurements on the tube amplifier since I almost never use it anyway. It's just an eye-catcher for visitors
Now I know that the tape recorder creates the so often praised "beautiful" vintage sound which is on most LPs before 1990.
I'm happy that I've finally solved this mystery for myself.
What I'm still missing is a DSP plugin in Roon that recreates the curves I showed here so I can finally switch to vintage sound with my transparent system. Unfortunately, I'm afraid we'll have to wait until Judgment Day for that.
I am interested to know if you have ever dealt with this topic and what your findings are.
Best DrCWO
