How to prevent brickwalling/clipping while recording

I have a Technics RS-B14 tape deck, and something I notice, that whenever the VUs pass above 0dB, the recording doesn't get any louder, it brickwalls and distorts, and begins to sound like the song is from a hot pressed 45 meant for radio use. Could I use a headphone amp, or find some other way to run it into my Mic input on my pc, and prevent this from happening?

 

The tape you're using has reached its saturation point. Analog tape normally compresses past the point of its MOL, or at the point of 3% harmonic distortion. The MOL and max saturation points are tape dependent and frequency dependent. If the music you're recording is already compressed a lot, and high in treble content (such as Metal or modern R&B) then the tape may not handle much past the 0 dB point.

Lower your level to -5 dB avg. Good recording practices should target -3 dB avg level as a starting point, then adjust to the program. (+5 dB peaks for dynamic transients) Your heads may need cleaning and demagging, probably not the cause of the limiting and distortion, but always a good idea anyway. Your deck may be out of calibration, the rec amp levels may be too hot, which requires a calibrated tape to line it up.

As a last resort, replace the deck.

 

And also be mindful most consumer machines have peak meters rather than Real VU meters. Which are mainly found on ReVox machines. Until you get into real studio machines.

 

Don't use the MIC input on your computer, use the AUX input!

Cripes.

 

It's a laptop. No can do...

 

Check control panel. There will often be an option called something like "Boost Volume" or "Increase Gain" or something similar. Uncheck that. If you're really serious I'd look at getting an external USB interface, which will allow adjusting levels, etc.

 

On a Mac, that input can be treated as a "line input" or a "mic input". I'm fairly certain this is the case on Windows machines as well. Check your "control panel" or "system preferences" if you're on a Mac. You can also control the volume your laptop is receiving from there. If you're just dropping cassettes, a USB device is overkill.

Ed

 

Turn the REC input knob counter-clockwise a bit If your deck has MONITOR ability suggest that so you can hear what is being recorded to your tape and make adjustment as needed.

 

So are tou talking about recording to tape or transferring your tapes to digital?

 

What exactly re you trying to do? Are you digitizing to your PC?

 

I am digitizing to my PC.

 

To anyone who is confused, I'm digitizing tapes to 24/96 onto my PC. I've never had any issues with compression whilst recording from my PC to my tape deck.

 

Does your tape deck have an output level control? If so, turn it down. If not, you can buy RCA attenuators to lower the level coming out of the cassette deck.

 

Just adjust the input level in the windows recording properties. Or buy an Asus Xonar U7.

 

It was set with the gain to +10dB(!). Turning this down to 0 saved the dynamic range (well, now that means I have to rerecord a little over 20 albums and and God knows how many hours of music. But, oh well.)

 

I might have to add about 40 albums to that list... (See my post on white powder/mold on cassettes)

 

Hey again, Avgvinylcollector, Better if you can include a link to your other discussion, http://forums.stevehoffman.tv/threads/mold-on-cassette-tapes.496213/#post-13713617
I have seen the white powder you describe. I have found it to be mold. The tape may or may not have a musty odor, but usually does. When I find this, I toss the tape to prevent contamination of the tape transport, cross-contamination to other tapes, and prevent scoring of the head. The mold can be manually removed from reel to reel easily enough, but just not practical for a cassette. Most cassettes can be easily replaced... so just toss em and replace.

BTW I have found that some cassettes are mastered well enough to be considered a valid high fidelity source. Capitol XDR tapes are just one example. Some tapes are high density ferric type I, always a better chance these will sound good with a lowered noise floor.

For better archiving of your tapes.. recommended in my opinion:

My playback deck is a Nakamichi 480, a very affordable two head deck. I have no complaints about the 480, which sounds better than the typical Technics or Sony deck, which are also good decks. What's so good about the Nak? It tracks most Dolby B pre-recorded tapes perfectly without high frequency loss. Another benefit is the narrow gap Sendust head, and the pressure pad lifter. Head wear is almost eliminated, and better tape to head contact maintained. There is never any tape skewing on a Nak. The Nakamichi Dragon and just a few other Nak models have an auto azimuth playback feature, and this is a great convenience for archiving your cassette tapes. For best high frequency response and phase alignment, the head azim must be aligned to each tape. Some tapes are perfectly calibrated, many are not, so the head azimuth must be aligned to the tape for the very best digital transfer.

http://www.tapeheads.net/showthread.php?t=17688

The caveat with Nakamichi, the decks must be refurbished and lined up by a pro. The original main belt should be reconditioned not replaced by an aftermarket belt. The aftermarket belt is thicker, and exerts more tension on the motor bearings, plus the anti-resonant mechanism will not function as it is designed to. Sometimes the original belt is stretched, (if stored in a hot attic for instance) but most are perfectly ok. The OEM belt (main belt only) is very high quality.. very thin and limber.. does not deteriorate, and will last a lifetime. (again.. never replace if not necessary) The machine will not perform to the same low wow and flutter spec with the replacement belt. The counter belt and cam belt do need to be replaced. These replacement belts are the same as the stock Nak belts.

I restore Nakamichi decks, but have none left for sale at this time.

If you are interested in how to manually line up your head azim to each tape, just let me know.
rock on,
Steve VK

 

I understand that my deck is not the greatest, and I would like to adjust the azimuth properly, according to the tapes and own a Nak deck, however, the closest place near me that repairs tape decks is around an hour and a half away from me, and there is a $30 down payment on everything (just to have a man look at it) and parts for a Nak deck would be rather costly in my current situation. I do plan to repair a deck I own (a belt is broken), it's a Technics RS-B57R, with dbx, Dolby B and C, and auto reverse. Would that one sound a tad bit better than the one I'm currently using?

 

Yeah, it's mostly the Dolby B alignment that's off on most mid priced cassette players. I owned a Sony WE 475 and loved it for its pitch control, but it had trouble tracking the Dolby on most pre-recorded tapes... typical dullness and chopped off audio on the fade outs. But it did just fine playing back it's own recorded tapes. The Nak was a surprise since I had never believed any pre-recorded Dolby cassette could ever play properly. But they certainly can and do, most of them.

You have to manually adjust your azimuth. You'll need a small precision phillips screwdriver. If your deck is a Sony, the azim screw is a torx head, a #5, I believe. Just one caution, be sure to discharge yourself of any static charge before adjusting the head, and only touch the insulated handle of your tool. I made the mistake of using my left have to guide the torx bit. I heard static come out of my speakers, and guess what? It recorded on the tape. So don't be like me, and be careful to not touch any metal parts when adjusting the head. Cause.. the tape has to be playing when you make the adjustment.

You'll a way to need mono playback to adjust. If your pre-amp has a mono switch, your set. If not, then you'll need to monitor the azim adj through the cassette headphone jack (with headphones) and connected through a double Y to convert stereo to mono in your headphones. This will not affect the stereo line out.

Here is how you do this, Please excuse the step by step numbering:
1) Carefully remove the cassette door cover. It slides up. Most azim screws can not be accessed with the door in place.
2) find the azim adjustment screw. it will be labeled "azim"
3) mark the screw head with a red marker, or a dot of white paint. This is your reference so that you can return the deck to its original alignment.
BTW the azim adjustment should require no more than 1/2 a turn. If more than that, then the tape is really way off.
4) Play the tape you're going to record, switch the Dolby off for now.
5) switch your preamp mode switch to "mono"
=or= slip on the headphones connected through the double Y from your cassette headphone jack. If your cassette does not have a headphone jeck, this can also be done from your pre-emp (or receiver) headphone jack. Again, the double Y will not affect stereo playback to your PC
6) everything so far is very easy, so, at this point your ready to adjust. With the tape playing, and listening in mono, the idea is to listen for maximum high frequency response. Turn the azim screw left (counter-clockwise) If the high freqs increase, keep turning until you hear a slight decrease, (you just went a bit too far) then turn back to the right until you again hear max high frequency response. If turning to the left results in no hi freq increase at all, then turn to the right, (clockwise) and listen for an increase. The adjustment should not be any more than half a turn, 3/4 at the most. If you have to go a full turn, just make a note of it, cause your reference mark will be at or near the same point you started at. (but will be a turn away from its original setting) When you hear max hi frequency response you're lined up to the tape. The Dolby may also track better at this point, so it wouldn't so any harm to test listen with the Dolby on. This method is extremely accurate, but has to be done in mono mode. (if you want to know the technical reason that mono makes that much difference, just ask... the short answer is that the L and R channels are spaced apart on the head. Mono blends any channel time differences and sharpens the audio and your adjustment) Once again, all we're doing is lining up the play head to exactly the alignment of the slave head the cassette was duplicated on. You'll get improved fidelity, in some cases a dramatic improvement.
7) Switch your pre-amp mode back to "Stereo". Turn the Doby B on if playing a Dolby tape ... (or leave it off if the tape sounds dull or choppy)
8) Set your record levels on your PC, and you're ready to rock!

Once you've gone through this a few times, it becomes super easy, so stay with it! You can congratulate yourself for making better sounding, professional sounding transfers.

any questions, just ask,

 

I overlooked also, if your setup is only to your PC, you can hook up the double Y (two stereo to mono cables) to the headphone jack on your PC. This will not affect your stereo transfer, a this is post- line level and used only for a mono monitor. The azim to tape has to be done in mono mode. If attempted in stereo without the double Y adapters, the adjustment can be made, but will not be nearly as accurate. The setup in my previous comment assumed your cassette is already connected to a pre-amp or receiver, and your PC connected to the tape monitor loop. With this setup, the mono switch comes in handy.