Hi, I'm going to digitalize some old vinyls, and I've few questions:

• my turntable has a strange problem: the right channel results "less amplified" than the left one, I think this could be corrected editing the file, but how to balance the amplification between the channels so that L=R in amplitude? One way could be: get the RMS power of the right channel, subtract that one to the RMS power of the left channel and using the resulting value to boost the right channel. Is it advisable or there are better ways?
  
• Is there a recommended recording level to set for acquiring audio from the phono input or it's just arbitrary (or source dependant)?
  
• I'd like to process the audio files for removing pop/clicks, restoring clips, correcting DC offsets, and normalizing (in case). Is there a preferable order for these operations? For example, it's better to postpone DC offset correction to clip restoration. What about the other steps?

Thanks in advance. Bye.

When i converted some records to hd,i used a editor and only dc was on....
On recorded files start first with clicks,pops.....nr should be next,and volume should be apsolytelly the last thing..Always record in uncompressed pcm format,and be sure that source volume is not clliping
also,check this page.. http://www.delback.co.uk/lp-cdr.htm

If this imbalace is on all records it may be better to solve the problem in your lp chain.
If the problem is only on some lps use 'Pan'; works like a 'balance control'.

I prefer to use -6db at 44.1/24bit.Please note that Creative Soundblaster does not support 24bit recording (probably others as well)

IMHO
1.Clean lp thoroughly
2.Manually correct major pops/clicks
3.Software correction pops/clicks;multiple passes(use chaining) at low sensistivity
4.Crackle
5.Dc/rumble 47hz filter 24db/octave
6.Noise
7.Tone
8.WAVES L2
9.Bit depth conversion to 16bit for CDA

Hope this helps.
PS: I prefer using monitors, not headphones.

Check that the antiskating of your turntable is setup properly. If so, your stylus is likely damaged or broken. Get a new one if you care about these records.

Excellent link.

Pio's suggestion to buy a new cartridge/stylus is a very good idea. My old Shure V15 type 5 had more noise on the right channel on most records. When I finally bit the bullet and bought a Grado Silver, the noise disappeared, tracking was much better and the sound was considerably improved across the board.

One caveat, the Grados are unshielded cartridges and can pick up a 60 cycle hum from some turntable motors. Some others in this forum may have other recommendations on different cartridges. The turntable/cartridge/stylus and cleaning your records are the most important steps in getting a good initial recording from lps.

if you want to squeeze a little bit more out of your deck, set the pitch control to as slow as it'll go.

it's a kind of complicated procedure to to it this way (more than i care to type at this hour ), but the results tend to be better than you'd otherwise get from your equipment.

my equipment is pretty bad, so i've had to do it this way

basically:

1. measure _exactly_ what the speed difference is between the correct speed and the slowed down speed (this can be done relatively easily if you have a record with a clear beat on it that you can accurately measure distances by). on my deck it's ~0.91119x normal speed.

2. de-emphasize the signal. this is done with some kind of EQ filter. i use Cooledit's FFT filter for it - set a RIAA eq curve, and use splines. make sure to use a short FFT window like 256, or you'll get ringing (not audible though. just annoying to look at).

3. using the speed measure, determine what sample-rate you're actually recording at. hopefully your recording software allows you to manually set a sample-rate after you've recorded (eg, i record slow LP at 44100, then manually set the rate to 48398).

4. at this sample rate, use the FFT filter to re-apply the RIAA curve. this will have to be re-inputted, because CoolEdit doesn't move it's points around according to sample rate.

5. resample (SSRC is good for this) to your desired sample rate.

i've got the above process semi-automated for my table - i did all the fiddly filtering to a simple impulse, and now i can do the rest with foobar's convolver and resampler.

i don't bother de-clicking unless there's a real monster crack. i don't see much point in it to be honest, as i like the vinyl sound. if i didn't, i'd just buy the CD instead of going to all that trouble

Could you explain why ?

The first reason would be extended frequency response from the phono pre-amplifier, but I think that 1.1 times the frequency response is negligible compared to the unevenness of the frequency response of the cartridge (usually around +/-1 or 2 db), not to mention the response of the record itself (up to +/- 5 db because of treble losses).

Another reason would be if the tracking is better at low speed (the tip better following the groove), but this has to be compared to the losses caused by the equalisation, then by the resampling.
Since the speed at the end of each side is one half of what it is at the beginning, reducing it 1.1 times seems small.

It would be interesting to compare a sample recorded at the normal speed with one recorded at low speed, equalized, resampled (you'd better record directly at the target sample rate if your card allows it, to avoid this process), and re-equalized.
The first thing to do would be ABXing them.

MugFunky

I read your sequence as

record slow linearly>apply RIAA>increase pitch>apply RIAA

Have I misunderstood you?
Wouldn't lowering the speed lower the low frequency into sub-sonic region?This would require recording at 88.1khz?

Pio is spot on about variations, I would add that sound balance varies widely between record labels and even the pressing plants ( Japanese vinyl being the best I have come across)

Hy,

I would simply get sure to have a nice cartridge and a good sounding preamp and then just get that on your HD at good level. Normalising ..... Finished!!!!

That will be just having your great sounding Records on your PC "AS IT IS!!"
Should be enoth. or not?