RMGI SM 468 vs. SM 911

T

themaddog

Rockin' & Rollin'
Hey everyone,
I've been trying to figure out which tape I'm going to use to mix my band's new album. Today I made the same mix onto SM 468 and SM 911. All of the signals were the same going in and out (as much as possible), the only exception being the final level going onto the SM 911 was about 3 decibels softer than the 468, otherwise it sounded too muddy and "garage-band."

I've uploaded each track here, but each download will likely take you awhile as they're 16-bit/44.1khz .wav files. The name of the song is "The Night Stalker."

http://www.nightstalkermusic.com/rmgi/ns468.wav
http://www.nightstalkermusic.com/rmgi/ns911.wav

The difference between the two was far more dramatic directly off of the tape, although you can hear some subtle differences in the tones on these digital versions.

To my ears, the SM 468 sounded much fuller. It is what I'll be using for the rest of the album.

-MD

***************************
More info for those who are interested:

The source was originally recorded on an MSR-16 using Emtec LPR 35 "Special Run" tape. The mix down machine was an Otari MX-50 NII. While mixing, I used the repro head off of the Otari to find the best signal level for the particular tape I was using. For the SM911, this meant that the signal had to be a little softer. When it was recorded onto computer, a Delta 44 sound card was used, at 16-bit/44.1khz (no dithering), at the same level for each mix. No computer adjustments were made, other than cleaning up the beginnings and ends of the tracks.
 
Man, I really look forward to listening to the above sounds. Will do it later tonight tho. Thanks for the uploads!! :)

Did you adjust the bias when printing to SM468 ? It does take a higher amount over the other tapes.

Also, is your MSR16 aligned / calibrated for Quantegy 456 (or its equivalent) ?

Sorry for the questions but I would like to get a bit of background on this before taking a listen. :)
 
Last edited:
Sorry, I meant if the mixdown recorder, your Otari, was rebiased for each tape (SM911 and SM468).
 
themaddog said:
http://www.nightstalkermusic.com/rmgi/ns468.wav
http://www.nightstalkermusic.com/rmgi/ns911.wav

The difference between the two was far more dramatic directly off of the tape, although you can hear some subtle differences in the tones on these digital versions.

To my ears, the SM 468 sounded much fuller. It is what I'll be using for the rest of the album.
Click to expand...

I listened to both versions and here's my take: I def agree that any transfer straight from tape to digital, even in wav, loses some but there is indeed a more "subtle" difference, as you mention. While both tracks offer superb production, instruments, vocals, lyrics, etc .... there indeed is more top end and a "fullness" you describe on the SM468 cut. HOWEVER, I would like to know if this is due to the tape or if you had not biased to SM468 properly. Too little bias can introduce too much highs and distortion on the lower end. Now, don't get me wrong, I really like what I'm hearing but I'd also like to know if it's tape differences, of such not so subtle scale, or if it's insufficient bias. :confused:
 
Last edited:
Hey cjacek,
I understand what you're saying completely. My Otari is biased for Quantegy 456. I'm not competent enough to re-bias the machine myself, as I've never done it and I don't trust myself with the electronics.

I mistakenly thought SM 911 and SM 468 were either bias compatible, or at the least bias comparable.

-MD
 
cjacek said:
Also, is your MSR16 aligned / calibrated for Quantegy 456 (or its equivalent) ?
Click to expand...

The MSR-16 is factory spec. from Tascam, so it is aligned for Quantegy 456, at I believe around +3 if I remember another post to this forum correctly.

I would assume this would mean that the MX-50, which is also calibrated for Quantegy 456, is set to +6.

-MD
 
Yeah, what Daniel said… A lot of people like the sound of under-biased 468 because the top end will sound brighter. It’s actually high-frequency harmonic distortion. The SM911 may sound dull in comparison, but you can also describe it as the 468 being overly bright rather than the 911 being muddy or dark.

Or something completely different…

Another possibility… the bias for the MX-50 is set for a something like 996 or 499. This would be too much bias for 911, and the high end would suffer. However the bias for 468 is higher, so although it would not be level compatible for a machine set for +9 tape it would be bias compatible. Higher operating levels also squash high frequencies, so if your MX-50 is setup for the +9 tapes (without your knowing it) it would make 456 or 911 sound darker and smeared.

The MSR-16 is factory calibrated bias compatible with 456 at 250 nWb/m (+3). The Otari MX-50 is also calibrated bias compatible with 456 at 250 nWb/m (+3), but adjustable between 185-510, and switchable between NAB & IEC.

If you have never had your Otari calibrated or checked it could have drifted or been purposely setup for something else by a previous owner. Setting up half-tracks that could do it for higher output tape was fairly popular when these tapes (3M 996 & AMPEX 499) came out in the early 90’s. The fact that you have to record 3 dB down when using 911 could indicate a bias and/or level incompatibility.

468 will retain highs better with higher bias, and is more tolerant of higher operating levels without dulling or smearing.

All things being equal, the tapes each have their own distinct character, and you may just prefer one to the other.

:)
 
Last edited:
Exactly as Tim (Beck) points out. MD, you really must calibrate / bias to have any semblance of accurate comparison between the tapes. You need to do a fresh setup with your TASCAM and Otari recorders. There is no way to get around it. You are getting a skewed sound picture of each tape and are not realizing their true potential.
 
Beck said:
Yeah, what Daniel said… A lot of people like the sound of under-biased 468 because the top end will sound brighter. It’s actually high-frequency harmonic distortion. The SM911 may sound dull in comparison, but you can also describe it as the 468 being overly bright rather than the 911 being muddy or dark.

Or something completely different…

Another possibility… the bias for the MX-50 is set for a something like 996 or 499. This would be too much bias for 911, and the high end would suffer. However the bias for 468 is higher, so although it would not be level compatible for a machine set for +9 tape it would be bias compatible. Higher operating levels also squash high frequencies, so if your MX-50 is setup for the +9 tapes (without your knowing it) it would make 456 or 911 sound darker and smeared.

The MSR-16 is factory calibrated bias compatible with 456 at 250 nWb/m (+3). The Otari MX-50 is also calibrated bias compatible with 456 at 250 nWb/m (+3), but adjustable between 185-510, and switchable between NAB & IEC.

If you have never had your Otari calibrated or checked it could have drifted or been purposely setup for something else by a previous owner. Setting up half-tracks that could do it for higher output tape was fairly popular when these tapes (3M 996 & AMPEX 499) came out in the early 90’s. The fact that you have to record 3 dB down when using 911 could indicate a bias and/or level incompatibility.

468 will retain highs better with higher bias, and is more tolerant of higher operating levels without dulling or smearing.

All things being equal, the tapes each have their own distinct character, and you may just prefer one to the other.

:)
Click to expand...

My MX-50 has been set up for 456 tape.

When I'm done with this album, the MSR-16 will be going into the shop for a little maintenance, at which point everything can be checked.

-MD
 
themaddog said:
My MX-50 has been set up for 456 tape.

When I'm done with this album, the MSR-16 will be going into the shop for a little maintenance, at which point everything can be checked.

-MD
Click to expand...

As long as you're sure it was setup by competent hands. The sad truth is these days if you don't learn to do it yourself you may never know for sure. :(

I don't let anyone touch my recording equipment or even my cars, unless the job is really beyond me.

Another thing I usually ask... where did you get the tape and was it new?
 
Beck said:
I don't let anyone touch my recording equipment or even my cars, unless the job is really beyond me.
Click to expand...

You too?! Man, that's scary! That's EXACTLY like me!! But even if it's beyond me, I don't let anyone else touch!! :eek:
 
Hey, MD ... It's really not that bad of a proposition. Even if you don't have an alignment tape or any other tools, other than a non-conductive flat tipped screwdriver, you can easily adjust bias. On a 3 head deck it's easy. It's like tuning / dialing in a radio to a proper station. This will at least give you more accurate tone.

Down the line, of course, it'd be to your advantage, as Tim Beck said, to learn the entire and complete process yourself.
 
Hey guys,
Thanks for the advice, I really appreciate it. About a year ago I tried calling some local studios in the area that still use tape to try to "intern" for a day or two to learn calibration and other basic maintenance, but there were no takers, even when I was offering money, he he.

The place I purchased the Otari from was at a really cool electronics repair shop called Aztech Electronics, where I had my Tascam 22-2 serviced once. One of the workers there said everything was set up properly on the Otari, and showed me the playback levels and recording levels were in spec with an MRL tape right then and there. Because I don't have a very thorough background, it's possible that he could have snowed me, but I really doubt it because the meters were right on.

If I were to adjust the bias for a tape, shouldn't I be adjusting the record and playback levels as well?

Oh yeah, and to answer Beck's question, the tape came from US Recording Media. It was the cheapest location for 1/4" tape, and the only place I could find that had RMGI 468.

Thanks for your help guys,
-MD
 
themaddog said:
If I were to adjust the bias for a tape, shouldn't I be adjusting the record and playback levels as well?
Click to expand...

Ideally, yes, you should adjust levels. However, I was merely suggesting a way for you to quickly, easily and without shelling out the bucks, adjust bias, which would make your tapes sound as they should. Bias pots are like a knob for a radio. Currently, you have it setup so that it's between stations or nearly getting good reception, meaning distortion.
 
You must log in or register to reply here.
Back
Top