Reply to Heaton's External Interface post

[Sonic Purity]

The original of this message is near the end of the thread on the topic "crossfade tunes", reposted here:

I want to use Amadeus Pro to capture the audio of LPs and cassettes.
I have a usb turntable for the LPs and a deck for the cassettes.

I have recorded some cassettes directly from deck to iMac and have
been generally satisfied with the results. But I have read that using
an external audio-capture device results in a cleaner signal and
better recording. Is this true? If so, I have my eye on the Edirol
UA-1EX usb audio interface, for less than $100. Would such a device
just sit between the cassette deck and line-in on the computer,
somehow resulting in a better recording than recording without the
device?

Is such a device desirable for recording from the turntable, or is
the fact that the turntable is usb good enough? If desirable, I would
appreciate a recommendation for a device that will enable recording
from both sources.

And if I may drift far from Amadeus, can I get better sound quality
from my external speakers by going through this same device?

Thanks for help.
CP

Opinions vary. It also depends upon the nature of the original source materials which you are working with: live recordings and audiophile recordings will likely have more dynamic range, and are more likely to benefit from a higher-end interface than what is built into a computer (any). I work with pre-recorded commercial audio (e.g. stuff originally from CDs, LPs, or tapes from recording labels), non-audiophile, so i find that with careful level setting, the built-in A/D hardware on my Macs is sufficient.

Audio interface devices like the UA-1EX (nice, from what i have read) sit between the analog audio source and the computer. No, it does not use the Mac’s line in… it itself is doing the analog to digital (A/D) conversion, and outputs USB (or for other devices, FireWire) digital audio into the USB (or FW) port on the Mac. Advantages of external A/D (and usually also D/A for the output side of things) include:

• Better circuitry
  Better isolation from the vast amount of internal digital noise inside a computer
  Sometimes more input/output options, or other features

Unless its circuitry is lousy, the USB turntable is not likely to benefit from an alternative connection. If it has an alternative which is line level out, that will probably not help, since some of the (assumed inferior, or you'd just use its USB out) circuitry is still in place. A direct low-level from the cartridge output might possibly benefit being fed into a nice external RIAA equalized preamp, then into your preferred A/D converter (Mac internal or something like the Edirol).

In terms of the output to your speakers, again it depends upon the Mac, how critical one is, and the nature of the audio sources. I am fairly critical though not an extreme audiophile, and i find the built-in audio output of most Macs i have used to be fully sufficient for both critical headphone listening and feeding into a good mid-fi component audio system with full-sized speakers. A friend who also does audio work and is an Amadeus owner/user who has an M-Audio Transit (competing product to the UA-1EX) finds no advantage/disadvantage to using the Transit audio output vs. his TiBook audio output and uses them interchangeably (actually probably the built-in output more often as that is slightly more convenient).

Honestly, unless every single cassette you are working with was made on the deck you are now using, the most profound improvements will be made with proper adjustment:

• Azimuth (this one is essential for excellent, clear results. Needs to be adjusted for each tape side.)
  EQ (120 µsec. vs. 70 µsec.)
  Noise reduction matching what was originally used

Similarly, the limitations for the record transfers will mostly be the mechanical and electrical limitations of the turntable, its cartridge/stylus, and its A/D converter electronics.

Best Digitization Wishes!

[MrEes]

And cleaning the tape path regularly.
m.
--
Michael Rees
Composer &c. <http://soundsgrate.net>

Continue for a long time
an event you hear.

On Nov 29, 2008, at 3:17 pm, Sonic Purity wrote:

Azimuth (this one is essential for excellent, clear results. Needs
to be adjusted for each tape side.)
EQ (120 µsec. vs. 70 µsec.)
Noise reduction matching what was originally used

_______________________________________________
Amadeus forum mailing list
Unsubscribe / change settings at http://two.pairlist.net/mailman/listinfo/forum_list

[heaton]

Sonic, I am overwhelmed. Thank you for taking the
time to respond in such detail. You have given me
much to think about. I hope I may ask a follow-up
question or two, even though unrelated to Amadeus
except that the finished product will be
processed on AP.

The originals of the cassettes I want to digitize
were made by having microphones and reel-to-reel
recorders on stage during music festivals of the
1960's. They were at a later time transferred to
cassettes. Each cassette I have has probably gone
through many generations, and that is reflected
in the audio quality. It is not great, but I am
happy to have the recordings at all.

Regarding your statement about recording cassettes to my iMac:

"Honestly, unless every single cassette you are
working with was made on the deck you are now
using [they were not], the most profound
improvements will be made with proper adjustment:

Azimuth (this one is essential for excellent,
clear results. Needs to be adjusted for each tape
side.)
EQ (120 µsec. vs. 70 µsec.)
Noise reduction matching what was originally used"

I take it that you mean "the most profound
improvements will be made with proper adjustment"
rather than with an external interface.

Re azimuth adjustment:
I had to look up what it meant. Apparently you
turn a screw and use your ear as your guide. My
best deck is a Sony TC-WE805S autoreverse deck.
The Audacity explanation of azimuth adjustment
says: "Azimuth is more complex on autoreverse
decks, and adjustment is not recommended unless
you know how the mechanism handles azimuth issues
and appreciate the implications of adjustment." I
will read up on azimuth adjustment in the manual
and see if a klutz can do it.

Re EQ: How and where is this done? In Amadeus?

Re: Noise reduction. I have no idea on these
dozens of tapes what was originally used. Any way
to tell?

Thanks again.
C{

The original of this message is near the end of
the thread on the topic "crossfade tunes",
reposted here:

heaton wrote:

I want to use Amadeus Pro to capture the audio of LPs and cassettes.
I have a usb turntable for the LPs and a deck for the cassettes.

I have recorded some cassettes directly from deck to iMac and have
been generally satisfied with the results. But I have read that using
an external audio-capture device results in a cleaner signal and
better recording. Is this true? If so, I have my eye on the Edirol
UA-1EX usb audio interface, for less than $100. Would such a device
just sit between the cassette deck and line-in on the computer,
somehow resulting in a better recording than recording without the
device?

Is such a device desirable for recording from the turntable, or is
the fact that the turntable is usb good enough? If desirable, I would
appreciate a recommendation for a device that will enable recording
from both sources.

And if I may drift far from Amadeus, can I get better sound quality
from my external speakers by going through this same device?

Thanks for help.
CP

Opinions vary. It also depends upon the nature
of the original source materials which you are
working with: live recordings and audiophile
recordings will likely have more dynamic range,
and are more likely to benefit from a higher-end
interface than what is built into a computer
(any). I work with pre-recorded commercial audio
(e.g. stuff originally from CDs, LPs, or tapes
from recording labels), non-audiophile, so i
find that with careful level setting, the
built-in A/D hardware on my Macs is sufficient.

Audio interface devices like the UA-1EX (nice,
from what i have read) sit between the analog
audio source and the computer. No, it does not
use the Mac's line in--it itself is doing the
analog to digital (A/D) conversion, and outputs
USB (or for other devices, FireWire) digital
audio into the USB (or FW) port on the Mac.
Advantages of external A/D (and usually also D/A
for the output side of things) include:


Better circuitry
Better isolation from the vast amount of
internal digital noise inside a computer
Sometimes more input/output options, or other features


Unless its circuitry is lousy, the USB turntable
is not likely to benefit from an alternative
connection. If it has an alternative which is
line level out, that will probably not help,
since some of the (assumed inferior, or you'd
just use its USB out) circuitry is still in
place. A direct low-level from the cartridge
output might possibly benefit being fed into a
nice external RIAA equalized preamp, then into
your preferred A/D converter (Mac internal or
something like the Edirol).

In terms of the output to your speakers, again
it depends upon the Mac, how critical one is,
and the nature of the audio sources. I am fairly
critical though not an extreme audiophile, and i
find the built-in audio output of most Macs i
have used to be fully sufficient for both
critical headphone listening and feeding into a
good mid-fi component audio system with
full-sized speakers. A friend who also does
audio work and is an Amadeus owner/user who has
an M-Audio Transit (competing product to the
UA-1EX) finds no advantage/disadvantage to using
the Transit audio output vs. his TiBook audio
output and uses them interchangeably (actually
probably the built-in output more often as that
is slightly more convenient).

Honestly, unless every single cassette you are
working with was made on the deck you are now
using, the most profound improvements will be
made with proper adjustment:


Azimuth (this one is essential for excellent,
clear results. Needs to be adjusted for each
tape side.)
EQ (120 µsec. vs. 70 µsec.)
Noise reduction matching what was originally used


Similarly, the limitations for the record
transfers will mostly be the mechanical and
electrical limitations of the turntable, its
cartridge/stylus, and its A/D converter
electronics.

Best Digitization Wishes!

------------------------
))Sonic((




_______________________________________________
Amadeus forum mailing list
Unsubscribe / change settings at
http://two.pairlist.net/mailman/listinfo/forum_list

_______________________________________________
Amadeus forum mailing list
Unsubscribe / change settings at http://two.pairlist.net/mailman/listinfo/forum_list

[Sonic Purity]

Sonic, I am overwhelmed. Thank you for taking the
time to respond in such detail. You have given me
much to think about. I hope I may ask a follow-up
question or two, even though unrelated to Amadeus
except that the finished product will be
processed on AP.

I’m fine with that, as long as Martin and our fellow board members don’t mind.

The originals of the cassettes I want to digitize
were made by having microphones and reel-to-reel
recorders on stage during music festivals of the
1960's. They were at a later time transferred to
cassettes. Each cassette I have has probably gone
through many generations, and that is reflected
in the audio quality. It is not great, but I am
happy to have the recordings at all.

Oh dear… right there there will have been enough analog generational losses that i can now confidently say that, even though the recordings were live, i highly doubt they will have surviving dynamic range sufficient to require something beyond the Mac built-in A/D. Each cassette generation is likely in the 40-50 dB dynamic range (i don’t remember the math on how these cascade… it reduces a bit with each additional generation), well within what built-in Mac A/D does well, with reasonably careful level setting.

Regarding your statement about recording cassettes to my iMac:

"Honestly, unless every single cassette you are
working with was made on the deck you are now
using [they were not], the most profound
improvements will be made with proper adjustment:

Azimuth (this one is essential for excellent,
clear results. Needs to be adjusted for each tape
side.)
EQ (120 µsec. vs. 70 µsec.)
Noise reduction matching what was originally used"

I take it that you mean "the most profound
improvements will be made with proper adjustment"
rather than with an external interface.

Exactly. It will still help, though not as much as for a single tape generation, since really this should have been done for every tape copy generation, and almost certainly was not done. So you almost certainly have cascading generations of azimuth errors, each one muddying the sound.

All you can do at this point is properly adjust the azimuth to match the actual tapes you have, and maybe slip the channels in Amadeus to partially correct the cascade of previous azimuth errors. This latter is done by vertically aligning the waveforms on loud, unique-shaped sounds which appear equally in both channels (if these are stereo recordings. If any are mono, further considerations apply).

Re azimuth adjustment:
I had to look up what it meant. Apparently you
turn a screw and use your ear as your guide.

Yes. Hopefully you saw my page on this subject.

My
best deck is a Sony TC-WE805S autoreverse deck.
The Audacity explanation of azimuth adjustment
says: "Azimuth is more complex on autoreverse
decks, and adjustment is not recommended unless
you know how the mechanism handles azimuth issues
and appreciate the implications of adjustment." I
will read up on azimuth adjustment in the manual
and see if a klutz can do it.

If you study carefully and proceed with caution, hopefully things will work out. On nearly all tape machines (cassette, non-pro reel-to-reel, other formats) azimuth is a technician’s adjustment only. On cassette machines, virtually always the azimuth screw is locked in place with locking glue, paint, nail polish, or the like. Any locking compound must be removed before attempting to turn the azimuth screw (or nut), else the screw (or nut) can easily be destroyed and rendered unadjustable by anyone.

Re EQ: How and where is this done? In Amadeus?

I was using shorthand to keep the message short. Some cassette decks switch bias and EQ separately, while others switch them together. Some switch these automatically by reading knock-outs on the cassette shell. This all has to do with the particular cassette tape formulation: Type I through Type IV, with I (“normal bias”) and II (“high bias”, formerly CrO2) being most common. In terms of playback, Type I uses 120 µsec. EQ and Types II-IV use 70 µsec. EQ. If your deck switches automatically, you’re taken care of. If yours has (a) manual switch(es), you will need to know what the Type (formulation) is on each cassette. Many cassettes won’t say, so you may have to do some research. There may well be websites discussing all this (mine is years from seeing daylight and mostly in my head).

Failure to properly match the EQ will result in frequency response errors. These can be corrected in Amadeus, yet would require a lot of care and some research, and are more easily addressed during digitization. While it is possible to correct for mis-set EQ in Amadeus, this EQ setting really ought to be done on the cassette deck during digitization for best results.

If any of the cassette transfers were done prior to 1975 onto normal-bias (Type I) tapes, there is another possible error: a different low frequency EQ. I am not aware of any decks which have a switch setting to deal with this. Unless you happen to have a working pre-1975 (or was it 1976?) cassette deck, this correction would need to be made in Amadeus or elsewhere in the digital realm. The difference is not huge, yet will affect bass response a bit.

Re: Noise reduction. I have no idea on these
dozens of tapes what was originally used. Any way
to tell?

By ear. Best bet may be to train your ears:

• 1) Make new cassette recordings of at least a couple of minutes at whichever noise reduction options are available to you.
  2) Listen to each recording with both the correct and every possible incorrect noise reduction setting.

Here’s what i hear (NR= noise reduction):

• * Dolby B encoding played back with no NR: exaggerated highs.
  * Dobly C encoding played back with no NR: exaggerated highs and maybe some mid frequencies. With Dolby B: slightly exaggerated highs.
  * dbx encoding played back with any other setting: “pumping” (weird sudden level changes).

None of these can be precisely corrected without proper decoding, though the Dolbys can be mostly ironed out via EQ adjustments (in Amadeus). I am not aware of any software dbx decoders, yet other board members may know of something.

Thanks again.
C{

Glad to help when i can.