I just got a Pro-Ject Debut II turntable (nice pink one :-)). However, every single record I play outputs one channel louder than the other. Not a huge amount, but there's a few dB of difference.

It's brand new out of the box and has the standard Ortofon cart. Any idea what's wrong, or how I can fix it?

Tony

PS, what the hell is this thing that came with it? And how do I use it? It's mentioned no where in the manual.


Thanks!

A consistent channel imbalance could be caused by incorrect cartridge azimuth. That's where the cartridge isn't absolutely vertical when viewed head-on. But since you say the difference is "a few dB", I don't think any azimuth error could produce such a large imbalance.

It strikes me that the most likely explanation is either a phono preamp with a channel imbalance, or a faulty cartridge.


I've certainly never seen a device quite like that, but from the picture it appears to be a combined stylus force gauge and alignment protractor. Do I detect a "knife edge" pivot about half-way along on the underside, plus what looks like a small metal weight at one end? Seems to me that you're supposed to put it on the platter, and then place the stylus at the opposite end to the weight, at or near the marking for 10/15/20mN, and the position where it balances out tells you the tracking force in milli-Newtons (10mN = 1g).

As an alignment protractor, it looks like you're supposed to place the hole over the centre spindle and then put the stylus on one of the positions marked 1, 2 or 3. It's difficult to tell, but judging from the size of the hole in the picture, I'd guess that those 1/2/3 markings might be about 70mm from the centre of the hole, in which case that position represents one of the null points for tracking error: with the stylus resting on the mark, the cartridge body should be parallel to the lines. Probably the reason for the three different points is to cope with different overhangs. (The overhang is the distance by which the stylus is "past the centre spindle", and can vary with different cartridges). But having a protractor with only one place for the null (at around 70mm from the centre) isn't really good enough. A cartridge should be set up with two null points: one at about 70mm, the other at about 125mm. The exact figures depend on the stylus overhang.

IIRC, a false anti-skating setting could cause channel imbalances ...

Thank for the reply guys. I have assumed that it was something to do with the cartridge azimuth, but I have no idea how to correct it on the Debut II (anyone?).

Thanks for the help on the gadget, your assumptions seem to be correct. I'll try it out in a little while.

The Debut II has no manual setting for the anti-skate, just one of those newfangled dangling weights.

Here's an MP3 expample of what I am talking about (although, the "few dB" I mentioned earlier seems to be a little exaggerated). http://www.naimarecordings.com/Turn%20Table%20Expample.mp3

EDIT/ Here's anothewr example which seems to be better. Maybe there's no real problem here, I'm a child of the digital age, so any discrepencies drive me crazy. Can some one tell me if there is a problem here, or is this as good as I will get?

http://www.naimarecordings.com/Turn%20Table%20Expample2.mp3

Thanks

I took a look at your two examples. The first one peaks at L=-6.7, R=-7.1, and has an RMS of L=-20.4, R=-21.2. The second peaks at L=-1.3, R=-2.3, with an RMS of L=-12.6, R=-13.3. So, the biggest imbalance seen anywhere here is just 1dB, which is within the tolerance of all but the most expensive pickup cartridges. So I think you're worrying about nothing. Listening to the examples, I'd say the recordings sound fine.

Thank you, that puts my mind at rest. I'm quite a perfectionist (the bad kind), so I hated the fact that something I had wasn't properly configured.

I was most worried though because I am about to do a whole bunch (150) 12" and LPs and I'd really prefer that this was the last time I done so (1st was LAME, 2nd was Musepack and now I'm going 44.1/24 FLAC)

I'd be interested in reading about your "production line" when you get it finalized. I have a friend (well, my therapist, actually) who's got about 300 LPs in his 800 LP collection that aren't available on CD and probably never will be...

-brendan

I'm afrad there's no secret. I record each 12" a side at a time. I then cut them up into tracks, fade in / fade out start and begining, normalise, FLAC then tag :-(

There's no easy way to do it.

To me, those audio samples you provided sound annoyingly-weighted to the L chan... That'd drive me nuts. Might you consider adjusting the recording gain of your R channel (if you can do so) on your audio interface whilst you're doing the recording? If the discrepancy is consistent then you can just do the adjustment once and then leave it... Use VU meters in audio software or, if you're using an Audigy card with the kX Project drivers like I am, the supplied VU meter plugin will work nicely for showing channel levels. I can also adjust each channel's gain independently or together, or set a difference and then lock it so that if I slide the faders they adjust equal amounts but stay the same distance apart (if you get me) - I'd definitely do something about it though, otherwise you'll come back to your recordings in a few months' time and think "ffs... Now I have to reedit them all, which means extracting the lossless copies, editing the WAVs, reencoding to FLAC, copying the tags over..."

And yes, I've also recorded _lots_ of my D&B vinyls, and some albums (variety of styles) (300+ and counting) to FLAC so that I don't have to constantly get them in/out of sleeves, coated in dust (which abounds in my room, what do you expect? I'm a student), get my grubby fingermarks all over them which are slightly acidic too... It pains me but it's for the best, and I can't fit a deck in my car whereas the MP3 player fits ok so that's great

I'm sure you'd like to get started on the records, but if you want to be sure you might consider buying a test LP to check the output levels. They were sold by retailers like Radio Shack and by cartridge manufacturers like Shure. Many used LP stores will have one or two lying around, or they show up cheap (> $10) on eBay as well.

Hmm. I was hoping there might be a specialty application out there that could start/stop writing the WAV output (it would always be sampling, however) from the sound inputs based on several rules such as:

1) Auto-start recording on sound input above a threshold level of x for longer than y milliseconds (needle landing).
2) Auto-pause recording when sound input remains below a level of x' for longer than y' seconds (end of last track). y' would need to be long enough so as not to trigger between tracks or for quiet segments.
3) Auto-pause recording after x'' minutes as second pause critiera for those records with a bad/noisy end of final track area and no auto-return or you have low-volume sources where you had to deactivate #2.
4) realtime crackle/pop filtering might be required to ascertain volume levels.

In addition, it could assist with track separation and tagging:

1) Each pause get recorded to an accompanying CUE file as track transitions, so that you've got a nice structure to work with in separating out albums, etc.
2) Since the program is always analysing the sound input, additional tracks marks could be auto-generated for suspected track transitions where the volume remained below a certain threshold.

That way, you can pipeline the sampling portion somewhat without having to hover constantly. Just feed LPs as you want

Perhaps the variables for those things are a bit too much black magic? I can dream, though.

-brendan

I was thinking of recording them all and batch processing them to reduce the left channel by around 0.8dB RMS. I just need to find software that will let me do it all in one go.

Another question I need to ask is, some of my records contain damaged 'S' sounds. Is this another result of my Turntable being setup poorly or is it just my old records?

Depends. Are these damaged 'S' sounds only on loud sections? If they are, then this is caused by mistracking. And in this case, the mistracking could be happening now, due to incorrect setup of the turntable you're using. And if this is the case, you need to stop playing your records until you've corrected the setup, because mistracking is the quickest way to damage the grooves. (Well, apart from playing frisbee with your LPs, of course).

Which brings us on to possibility two. If the damaged 'S' sounds happen only on loud bits, they could easily be the result of prior mistracking when the records were played on a previous (inadequate) turntable. In this case, the damage is done: the grooves have been permanently trashed, and there's nothing you can do about it.

Finally, if you're hearing excessive sibilance even at low levels, this is more likely to be due to inadequate capacitance in the phono preamp input. In this case you could experiment by adding small amounts of capacitance between the signal and ground wires (try values between 100 and 300pF).

PS. To the chap who said he thought the recordings were obviously over to the left: either you are hyper-sensitive to channel balance, or there's something wrong with my amp/headphones/ears, because when I listened to them they didn't seem off balance by any significant amount. Indeed, I'd go so far as to say that had I not known about the slight channel imbalance, I wouldn't have even noticed it on casual listening.

Yes, they are only in the loud sections. I read though the manual and it says nothing about azimuth. However, I had a mess around, turned some screws, and now the channels are almost balanced (actually, R is now a little louder). The Distorted Ss are now no more. I guess I just have a little more tweaking to do before I can find a proper balance.

I'm not sure I could hear the imbalance in the first recordings either, but since I watched them record I could definitely feel it...

I think I've cracked it! I assume that this is the best I will get (RMS is the most important, yes?)

Have you tried playing a monophonic record?

That's a very good idea. I'll try and digg one out and see what I can find.

For best results if you want to check with a mono LP, try to find one actually from the mono era (i.e. from the mid 1950s). Although mono LPs continued into the next 10 years later ones were often mastered using stereo mastering equipment which may not have been aligned perfectly itself.