Recording Mono LP Records

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Mike_12
Posts: 3
Joined: Thu Mar 25, 2010 10:22 am

Recording Mono LP Records

Post by Mike_12 »

Greetings to all: A beginner here.

Should I record mono Lp's as mono (on one channel) for the purpose of restoring? My intended use is for
CD's and mp3's.
I am open to other methods.

Mike_12;
DougDbug
Posts: 2172
Joined: Wed Feb 16, 2005 3:33 pm
Location: Silicon Valley

Re: Recording Mono LP Records

Post by DougDbug »

Stereo!

I use Wave Repair ($30 USD) to remove "Clicks", "ticks", and "pops". When you have a defect that occurs in one channel, Wave Repair has a nifty feature that allows you to copy a few milliseconds of audio from the good channel into the bad channel to eliminate the defect. Even when a click occurs in both channels, there is often a few-millisecond delay between the channels and this trick works. (This normally even works with stereo records, since you don't notice the few-milliseconds of mono.) Wave repair has some other repair methods too, and if you're willing to take the time to get the best possible results, I recommend that you give it a try.

A simpler option is to record in stereo, and then blend the channels together (into one mono file or two identical stereo channels). This has the effect of reducing the average noise level (the same thing happens if you use a mono cartridge, or mix the left & right with a mixer.)

Or, you can simply choose the best-quality channel for each song (after recording in stereo).

CDs are always stereo (2 channels), but your burning software will probably accept a mono channel and then automatically duplicate it. ...Oh, if you're duplicating the album artwork and can't find an image online, I've recently discovered that Fed-X Office (Kinko's) has a scanner that's big enough to scan an LP cover.

For MP3s, it's slightly better to use mono. If you use the "Joint Stereo" (the "smart encoding" option you should be using anyway), there is very little penalty to encoding a mono file (except your player software will see it as stereo). However if you use the "Stereo" option, you will loose quality (or get a bigger file) by compressing the same data twice. See HydrogenAudio.org for recommended LAME MP3 settings.

Something you can consider is creating "simulated stereo" by applying slightly different complementary equalizer adjustments to the left & right channels. But if you do anything that "drastic", you should probably keep an original mono archive. (I've actually converted a mono concert soundtrack to 5.1 surround, using panning, reverb, etc. whoo-hooo!)

For further reading... :twisted: ...My "standard comments" about recording LPs.
DougDbug wrote:
There are lots of hints & tips about recording/digitizing/cleaning-up LPs on this page.

I will almost always do the following:

If the CD is available, I'll buy it! My LP-to-CD transfers almost never turn-out quite "CD quality". (It's sometimes impossible to remove all of the noise.)

I always check for clipping. I run Maximize to check the peak level, and if it's 0dB I assume it's clipped and I re-record. (Clipping is distorted flat-topped "waves", caused by trying to go above the digital maximum of 0dB.)

I use Wave Repair ($30 USD) to remove "ticks", "clicks", and "pops". It does an amazing job by replacing the defect with the just-preceding or just-following few milliseconds of sound (or a couple of other methods). WARNING - This can be very time consuming. Wave Repair seems to work best when used manually. It usually takes me a day (or a weekend) to fix-up an LP.

I try some noise reduction and/or noisegate. Sometimes there can be artifacts (side effects), so I don't always apply these "filters".

If it's an old "dull sounding" recording, I'll add some high-end boost (with the Equalizer).

After I'm done with any other processing, I always Maximize (normalize) or use GoldWave's MaxMatch. This sets the level so that the peaks are exactly 0dB, giving the best signal-to-noise ratio at playback time. It's generally best to normalize the whole album as a single WAV file to retain the relative level between the tracks... Some songs are supposed to be louder or softer than others.

Whenever I burn a CD, I always make an extra archive/back-up copy. If I'm doing lots of processing, I make an un-processed archive CD too.
Mike_12
Posts: 3
Joined: Thu Mar 25, 2010 10:22 am

Re: Recording Mono LP Records

Post by Mike_12 »

Thank you for the quick reply and clarification to my question.

Using GoldWave to get the two equal channels. Should I select (Average) in the Device Property tab
under Mono source. I did a test with these settings. Both channels appear to be the same and sound
the same. Is this the correct way to achive the results i need?
DougDbug
Posts: 2172
Joined: Wed Feb 16, 2005 3:33 pm
Location: Silicon Valley

Re: Recording Mono LP Records

Post by DougDbug »

Assuming you want the best results, my advice is still to record in stereo... You can create a mono file later if you wish...

I've never used "average", but it would appear to give the same result as as where I said "A simpler option..." Except "average" is even easier!!! ;) If your records are in good condition and you're getting satisfactory results, you can use that option.

However, this will make if more difficult to remove clicks that appear in only one channel. If you want to try Wave Repair, record in stereo. If you want to pick the channel with the least noise, record in stereo and then pick the best channel from the digital stereo recording.

The signal (music) is mono, but the noise is "stereo". *

The advantage of recording in stereo is that you can make these decisions later... i.e. If it turns-out that one channel has a loud click, you can take advanatage of the channel differences.


* The signals are coherent (and identical). The noise is random and uncorrelated... When the left & right signals are added together the signal level increases by 6dB. When the left & right noise are added together, the noise level increases by 3dB. ....So when you mix the left & right together you improve the signal-to-noise ratio by 3dB (on average). This is a slight improvement, and sometimes you can do better by just selecting the quieter channel.
JackH
Posts: 100
Joined: Sat Mar 27, 2004 3:27 pm

Re: Recording Mono LP Records

Post by JackH »

I agree; recording in stereo gives you more options. You can then use GW to create your mono file.

You'll usually mix the two channels together equally. This will give you a sizeable reduction in noise, especially at low frequencies. To do this, go to Effects -> stereo -> channel mixer and choose the "Mono mix" preset. You can then select one of the channels, copy it, then paste it as a new file which will be pure mono.

Sometimes, it will be better to use only one channel of the stereo recording, however. This can happen if the record has been damaged, typically by playing it on poor equipment (I find that the left channel seems to be damaged more often). In this case, just select the channel you want to use, and do a copy/paste new. You won't get the noise reduction benefits by using this method, but it might be better anyway... just use your ears to make the judgment!
Mike_12
Posts: 3
Joined: Thu Mar 25, 2010 10:22 am

Re: Recording Mono LP Records

Post by Mike_12 »

I am looking to get the best quality possible. The guick fix is not for me.

After rereading the link and posts. (several times) I was able to grasp how to
get the two blended channels. I was making it out to be more complicated
than it is.

Did a couple of sample tests to get the technique down. I must say i am very plaesed
with the results.

Thank You: Mike_12
DewDude420
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Joined: Fri Mar 11, 2005 11:15 pm
Location: Washington DC Metro Area
Contact:

Re: Recording Mono LP Records

Post by DewDude420 »

I am looking to get the best quality possible. The [q]uick fix is not for me.
Now that you've said that, here's where I come in telling you the PROPER way to rip mono LP's. My first piece of advice is to likely throw your turntable away. Why? You cannot do a mono LP properly with a stereo cardridge on a normal turntable...you just can't. When record are cut, they're cut on a tangent. Pivotal arm turntables, which have been the standard for MANY MANY years (since the invention of the gramophone disc dates back to the 1880's, right after Eidson came out with his cylinder system), do not track the record the same way it was cut. Since it can only pivot in one place, the cartridge does not stay in proper alignment with the record groove...as it moves inside it "skews" off a few degrees. This causes a SLIGHT time difference between channels. This effect is less noticeable on stereo because the channels common contain different information...however, when you play back a mono record, as the record goes toward the inside, the channels slowly drift slightly out of phase, then back in to phase as the arm reaches it's second null point right around the area of where a 7" 45rpm would begin...then it slowly drifts out of phase toward the end.

This is inhereant to pivotal arm tables....there's no way to avoid it. It's basically a flawed way of tracking a record. They do make turntables that track on a tangent...they're called linear tracking tables. On these tables, the tonearm is mounted to a carriage of sorts that moves across the record, in a straight line, keeping the cartridge in perfect alignment across the entire record.


Now, why does this matter? Well, that time-phase will screw you up IF you decide to mix to mono later, it can also screw up if you decide to replace a defect in one channel with one in another....sure, it'll work, it'll sound ok, but in reality, one channel is a fraction of a second ahead and or behind the other. The main thing is if you decide to downmix this to a single channel later...a simple merging of channels will cause a phase-offset and can cause frequencies to disappear and odd strange somewhat hallow sounding effect.

There's several ways around this. The most expensive option is to pick up a Linear tracking turntable if you're going to be doing a lot of LP's, it ensures a "perfect" tracking of the groove every time. These however can be damn near IMPOSSIBLE to set up properly.

The second cheaper option is to pick up a true mono cartridge for your turntable.

Third option is to record in stereo....and do your restoration as normal, but only keep the left or right channel, discarding the other entirely.

If your turntable doesn't have the option to change the cartridge, then I'm sorry, but from a professional standpoint that table is not fit to transfer LP's. Yes, it will work...but generally a turntable that has a fixed cartridge is of questionable audio quality to begin with (ie...it's cheap).

Restoration is pretty standard, and has been covered here by other people. If you want to get REAL serious and want absolute top-notch restorations, Goldwave is a good program, does a great job, but Audition has a few other tools that makes restoration of vinyl a bit better.
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