I recently joined this forum group and am intrigued by this ongoing debate regarding dynamics expansion. I've been recording LP to CD off and on for the past several years but kept putting it aside because I couldn't get the 'magic sound' I recall when I blasted these recordings in my youth. I've looked at software dynamic range expanders and other audio 'enhancers', but still couldn't get the rich, dynamic sound I knew was on these records.
In recent times, I've grappled with the definition of dynamics in terms of what we hear, or what impresses us as 'dynamic'. The question as to whether an LP is as 'dynamic' as a CD is becoming moot as the music on many CDs these days is recorded with far less actual dynamic range than what could be heard on LPs. Apart from the added RIAA equalization of LP's, both media apply normalization (as opposed to dynamics) to get the most sound out of them. My view now is not whether dynamic range is important; its more the normalization engineered into the recording itself that concerns me.
The question is what kind of normalization? Simple gain normalization is the same as turning the volume up to a set level. RMS normalization, on the other hand, essentially raises the average sound level of a recording within a given dynamic envelope. This tends to bring up the quieter passages more than the louder ones and is basically a form of compression, but the implementation of it is different. In this form, most of the instruments are lifted to a perceptually higher averagevolume, increasing their audibilty and the overall apparent clarity of the sound. If not overdone, it can make a recording sound more 'dynamic' by virtue of this effect. This is not news; practically every recording you've heard has had some form of what is effectively RMS equalization applied in the studio. You can see this in the waveforms in any wave editor. In the early days, it was more necessary in order to make full use of noisy recording media.
The practice of recording with a wide dynamic range, such as what one might experience with a full orchestra in a quiet concert hall, was experimented with in the earlier days of digital audio. It has fallen out of favour, as such recordings are impractical for the everyday listening environment of most consumers. In my experience, increasing the dynamics of a recording won't improve the sound. Rather, careful initial recording to the hard-disk with a mind to preserving the dynamics in the vinyl, plus the use of subtle equalization and maybe some RMS normalization (if necessary) will.
My current approach is to input the soundcard from the pre-amp as loudly as possible (metered typically within -.5db). I also apply real-time software sub-sonic filtering during recording to stabilize the written waveform for the fullest dynamic range possible. As my record player sits on the desk above the pc, I've taken extreme steps to minimize the vibration from the cooling fans, and have achieved a noise reduction of better than -10db this way. Plus, I always record with the speaker volume off. After recording, I clean the sound with Wave Corrector, doing a single level 3 scan, then make a few adjustments to the larger corrections. If the surface noise is still unbearable, I'll do a fingerprint noise reduction, but only as a last resort. In most cases with pop music , all that is required further is maybe a little bass eq, to simulate the punch that high volume feedback from the loudspeakers gives, or a bit of treble. Sometimes with quieter music, an RMS normalization of about -8 or -9 db brings considerable life to the sound. The effect is not as good as a studio track remastering, but it comes close. If I use it, I apply the bass afterwards; it gets quite a boost this way. Ofcourse, the gain has to be adjusted downward prior to this.
It has been my experience that this approach gives the best overall sound reproduction. If the vinyl groove is not too bady worn, the sound quality compares favourably against the commercial counterparts (especially the early transcriptions). If the groove is badly worn, or if the recording was poor in the first place, I haven't yet found a way to fix this. I have to agree with Derek: I don't believe that dynamics expansion will improve the sound in any way.