Frequently Asked Questions
For questions concerning the Music Server features and general audio system connections, also consult the Pure Music Tips and FAQ and Getting Started with Computer Audio.
Technical / Features Q&A
Note: there is a known issue in the new Pure VInyl 3.11 update preventing audio input if the input and output are set to different devices, such as when using the computer's built-in audio. Pure Vinyl is normally used with an external audio interface, where input and output appear as the same device, so Pure Vinyl 3.11 functions properly in that case. This behavior is due to performance optimizations made in the new release. We expect to post a solution soon. If using the built-in audio for recording, the 3.01 release can be used as a workaround (link on Download page).
Technical / Features Q&A
I was looking for information
on how to connect a turntable to use Pure Vinyl. What do I need?
A detailed guide with
recommended components has been moved to
Also see photographs of setups with audio interfaces on our Getting Started with Computer Audio page.
Information on adapters for connecting turntables to audio interfaces (including DIY wiring diagrams) can be found here.
I read on the Internet that Apple Lossless
converts the resolution of 24 bit audio to 16 bit before compressing. Is that true?
Incidentally, Apple Lossless is a variant of the FLAC file format, and uses a similar compression algorithm (although the two aren't strictly
identical). Both preserve 24 bits of information. Apple lossless also adds the
capability of compressing 32 bit float format, and 176.4 / 192 kHz sample rates,
which were unsupported in the original FLAC file specification; the
standard FLAC format
also does not include a decoder for 32 bit format.
plan on releasing a Windows version of Pure Vinyl?
request that we've often received via email, and from folks that have visited us at audio shows
since 2006, when Pure Vinyl was first released. We've been thinking about making a Windows version of Pure Vinyl for some time.
We don't have a Windows version now, but here are some things to consider:
A lot of the incentive
for creating a Windows version was removed when Apple introduced the Intel processor Macs, which also
function quite nicely (dual boot) as Windows machines. A MacBook or Mac Mini are perfect
for this, a Mac Mini being especially elegant (and silent) for the listening room. Installation of XP
or Vista on an Intel processor Mac is very, very easy.
Install XP / Vista, and use the computer just like a Windows machine, in your familiar environment.
Boot into OS X for Pure Vinyl (hold down
the Option key and you immediately get to choose which OS you want to use).
You can even set the Mac to launch Pure
Vinyl automatically on boot, and you don't even have to have a monitor or keyboard
connected (such as on a Mini or other non-laptop). Optionally, you can remote control everything from the
listening chair over ethernet from
another Mac, via VNC, such as with a MacBook, perched on your lap or side table.
A virtual monitor of the other computer appears in a window on the
laptop, just as though you were sitting at the Mini. It's a piece of cake to set it up,
and it works beautifully.
In fact, we do exactly that, using VNC at the
Rocky Mountain Audio Fest
in our demo suite, controlling Pure Vinyl (
running on a Mac Mini)
from the listening position with a MacBook. This included (in 2008; for 2009 a single amplifier
and pair of speakers was used) switching between different
amplifiers and sets of demo speakers, remotely, at the touch of a button on the computer.
(Note: if you're an audio product exhibitor that would like a similar setup,
If you're using a PC because you need to use other audio software, such as DEQX, there's
still a way to use a Mac, and run the PC software: by using a virtual-machine (VM) type emulator,
such as Parallels on the Mac, which
runs Windows in a separate "window," running concurrently with Mac OS X.
Boot into Mac OS, and fire up the VM software, administering the Windows software from the VM environment.
Accordingly, both applications (the Windows software and Pure
Vinyl) may be run simultaneously on the same computer. (The opposite, running Mac OS X within a PC boot
environment, isn't possible, as far as we know.)
(As further incentive, Pure Vinyl also has a
music server feature for playing back tracks from iTunes playlists, which
includes a high-resolution upsampling feature for CD format music to 88.2/96/176.4 or
192 kHz 24 bit; and also has a
low-latency distributed-audio NetSend feature that can be used to stream high-resolution
audio to a remote computer, plus acoustic propagation delay correction to eliminate echoes
from multiple loudspeaker systems; if you have a large house, you're likely familiar
with that problem...)
|The signal to
noise ratio of analog audio from a vinyl record is between 50
to 70 dB, while 16 bit digital audio has a dynamic range of 96
dB! Why should I waste disk space recording vinyl at 24 bits,
when 16 bits should be more than enough?
Dynamic range is just
one factor that determines the quality of digital audio reproduction.
Besides the advantage of using 24 bit resolution during the initial
recording to provide extra headroom in setting the recording
level, there's also the matter of sampling resolution.
A 16 bit digital word
resolves loudness levels in steps that are 1/65,536 of the full
scale signal. In other words, when an audio signal is digitized,
the permissible values of the digitized result only can occur
in these discrete (quantized) steps.
Digitizing a vinyl recording
with 16 bit resolution forces the audio to be represented by
these 1/65,536 digital loudness steps. This process occurs at
every digital sample. (The total number of samples representing
the waveform is determined by the sample rate, yet another factor
affecting the audio quality.)
With 24 bit audio, the
resolvable levels are much more closely spaced together. Instead
of 65,536 possible loudness levels, there are 16,777,276. In
other words, the loudness "steps" in the waveform will
be 256 times finer (this isn't the same as "oversampling,"
which refers to the sample rate). Consequently, audio sampled
at 24 bit resolution more closely resembles the original analog
signal than if sampled at 16 bit resolution. Note that "32
bit" resolution, sometimes mentioned in this context, doesn't
indicate the resolution of the audio interface; the 32 bits just refers
to the resolution of the digital stream used internally for processing
by the computer (with two
very uncommon exceptions, after the introduction of
32 bit digital converters from AKM and ESS in late 2008).
Pure Vinyl's internal signal processing
path goes even further than that, by using 64
bits (known as double precision floating point) of resolution.
The reason for using
24 bits rather than 16 bits is just to preserve the original
signal as faithfully as possible. "High rez" 24 bit
192 kHz digital audio, reproduced from a high quality audio interface,
is widely regarded as being indistinguishable from the original
only extends to 20 kHz, so why should I bother recording at 192
It's all about preserving
the signal from the vinyl recording as faithfully as possible;
First, more, about the "more:" as has been
sampling at a higher rate moves the
phase shifts of the antialiasing (ADC) and reconstruction (DAC) filters outside
the audible frequency range. It sounds better! But besides the
audio quality, there also is the issue of capturing all that's on the LP:
Unlike the Compact Disc
(CD) format, vinyl is capable of reproducing frequencies well
above the accepted limit of human hearing. While there is debate
about whether or not (or how commonly) humans are capable of
perceiving frequencies above 20 kHz, the
effect of the "brick wall" filter used in CD production,
that sharply attenuates frequencies above the 22.05 kHz Nyquist
limit, is harmful to the reproduction of audio, by introducing
ringing and phase shifts affecting signal frequencies below
20 kHz. Vinyl has no such limitation on the frequency response;
just the smooth roll-off imposed by the mechanical properties
of the stylus; no brick-wall.
If you don't believe
that vinyl "has" anything above 20 kHz, check out this
example, illustrating why it's worthwhile to record / archive
the audio at the highest possible sample rate:
above image for vinyl frequency response analysis, and comparison
with CD "brickwall" 20 kHz response.
The high frequency tails
in the audio recording shown above require a sample rate of at
least 192 kHz for capture. In keeping with the notion of the definition
of archival as being faithful to the original, this information would
have been lost if the
recording were transferred at a lower sample rate.
Finally, the RIAA compensation filter of
Pure Vinyl functions more effectively at higher sample rates.
|I downloaded a free
plug-in setting for "RIAA filtering" for the equalizer in my
audio software / audio interface. (Or, my audio interface includes an "RIAA FIlter.") So, why should I
purchase Pure Vinyl for this?
Accurate emulation of an analog RIAA filter
cannot be realized with a general-purpose graphic or parametric equalizer
plug-in through a so-called "RIAA filter setting."
Even in the days before digital audio, using a graphic or parametric EQ
to attempt to emulate the RIAA curve would have been unthinkable.
The reason is that the state-variable, notch or bandpass types of
filters used in graphic or parametric equalizers (and
FIR, which stands for Finite Impulse Response type filters,
used in digital equalizers),
while extremely flexible for general audio processing, have
incorrect phase and amplitude response profiles for this purpose.
Instead, Pure Vinyl uses first-order
digital IIR (Infinite Impulse Response)
filters. This particular class of filter is noted for behaving identically
to its analog, first order (resistor - capacitor) minimum phase counterpart, while being unburdened by the
well-known limitations of physical resistors and capacitors.
Pure Vinyl's 64 bit first-order filters for the
standard RIAA curve breakpoints were designed by
computer modeling as a first step, and then carefully hand-tuned,
tested and optimized to match the
standard RIAA response, at a variety of sample rates, and finally, evaluated
through extensive listening tests, in a process that began years before
Pure Vinyl version 1.0 was publicly released.
If you try a parametric or graphic
equalizer approach to RIAA filtering, don't be surprised if the results prove to be
unsatisfactory, and likewise, such a test shouldn't be used to draw any conclusions regarding
the level of audio quality attainable
with properly implemented software RIAA filtering.
Pure Vinyl RIAA FIlter Advantages
Audio interfaces such as the Prism Sound Orpheus / Metric Halo have onboard signal processing with an option for an "RIAA filter." However, there are many significant advantages to using Pure Vinyl's RIAA correction, compared to using the RIAA curve in such hardware (or a conventional phono stage):
1. The RIAA filter in Pure Vinyl is minimum-phase, the same as a conventional phono preamplifier. Unilke a conventional phono preamplifier, there is no drift in performance due to component temperature coefficients, no interchannel amplitude or phase variation due to component tolerances, and no added distortion from the RIAA correction.
2. There is an adjustable (frequency and slope) rumble filter which is invaluable for vinyl playback, to remove low frequency
information which reduces the headroom in recordings and in the power amplifier.
3. If archiving / transferring to digital, you aren't locked into having a pre-corrected recording. The curve can be applied any time later. You also can produce copies using Pure Vinyl with the RIAA curve applied, in a choice of formats (including with sample rate conversion) so one need not rely on Pure Vinyl for playback.
4. The RIAA filter in Pure Vinyl is calculated with 64 bits of precision. Hardware DSP chips are limited to 32, 40 or 48 bits (depending on the chip). While the signal is in the digital domain, one also can use Pure Vinyl's crossover feature (also calculated at 64 bits of precision), optional high quality 64 bit sample rate conversion, or signal processing or signal analysis (AudioUnit) plug-ins.
5. Besides the standard RIAA correction curve, Pure Vinyl includes over 60 alternate correction curves for use with antique recordings.
6. You don't have to be nearly as careful in setting the recording levels. The RIAA filter actually increases the effective resolution / word length (an AES Convention "white paper" on this topic can be downloaded from this website). This is used to advantage, because it can be integrated with the filter (during playback or optional sample rate conversion of the "flat" recording) if any normalization gain is needed. On the other hand, if recording directly to a 24 bit file with the RIAA curve already applied, any normalization done afterwards will only increase the distortion in the recording.
7. There will be additional options added to Pure Vinyl to take advantage of the characteristics of the "flat" transfer. For instance, pop and click removal is much more effective when used with the "flat" recording, because pops and clicks will not have been altered by the RIAA filter of a conventional phono preamplifier. On the LP the music has been processed with RIAA pre-emphasis but pops and clicks, arising from physical defects in the vinyl or contamination of the LP surface, have not. The RIAA filter acts as a pulse stretcher on the fast rising pop / click impulse, making impulse noise removal more complicated than it should be.
Because of these reasons, it should be apparent why it's much better to use the RIAA correction in Pure Vinyl instead of a plug-in filter or signal processing option provided in your audio interface (or a conventional phono stage)...
|I've read on
the Internet that by using a software RIAA equalization / correction
system such as yours, I throw away 6 or 7 bits of resolution of
my audio interface! Is that true?
That's incorrect, and
is a misconception based on a simplified view of the software-based
RIAA correction process.
This subject was the
focus of a technical "white paper" (available on the
presented at the October, 2007 123rd Audio Engineering Society
Convention in New York. The slides from the presentation also
are available for download.
The paper (#P4-6, Filter Reconstruction and Program Material
Characteristics Mitigating Word Length Loss in Digital Signal
Processing-Based Compensation Curves Used for Playback of Analog
proves that software-based correction doesn't compromise audio
In fact, converting the
amplified analog vinyl signal to digital with the RIAA treble emphasis
intact, followed by applying the correction curve in software
enhances the available digital resolution in the midrange
and treble, where human hearing is at its most sensitive,
compared to digital conversion after RIAA correction.
Pure Vinyl performs all internal signal processing at 64 bit
resolution, which preserves the benefit of using the pre-emphasized
signal (and, as a bonus, no distortion is added). Openness, clarity
and definition in the midrange and treble are improved, compared
to doing a digital conversion after the signal has been
corrected with a conventional phono preamplifier.
More importantly, our
Pure Vinyl users have reported (both via the Internet and in
person, when visiting our demonstrations at audiophile shows
like the Rocky Mountain Audio Fest) that combining software RIAA
correction with a high resolution (24 bit / 192 kHz) audio interface
(and a quality gain stage) provides noticeably improved "live"
vinyl playback, compared to a conventional (including high-end)
Incidentally, a practical avenue to
implementing software RIAA correction as a viable "live" vinyl playback system has only
become available in the last several years. The key enabling technology was the
introduction of high quality, high resolution audio interfaces, coupled with
the availability of powerful, inexpensive computer hardware.
is more expensive than the iMic and the free, open source software that I'm trying to use to digitize my
old records. I don't understand why I should spend more when
the iMic seems to do a good job. What's the difference?
While the iMic is a remarkable
device at its price point, there naturally are limits to what
can be expected from the performance of a combination microphone
preamp and audio interface retailing for approximately $40. (If
that were incorrect, then companies selling expensive microphone
preamps and audio interfaces, running into the price range of
thousands of dollars each, would go out of business. That hasn't
It's unreasonable to
expect to achieve high quality vinyl playback from even a conventional
phonograph preamplifier retailing for $40 (they do exist). Likewise,
the many engineering hurdles to be met when creating an audio
interface that achieves truly high-resolution digital audio reproduction
simply cannot be overcome at that price point. If, after listening
to your recordings, you find that the iMic isn't delivering the
sound quality you expect (as in low noise, dynamic, crystal clear
detailed sound that also doesn't cause "listening fatigue"
when played at louder levels), then you should strongly consider
upgrading your audio interface. The enjoyment of recorded music,
whether from vinyl or other sources, always is enhanced by using
better quality equipment. And if you're going to invest a lot
of time into making format conversions of your vinyl, don't you
want to have the best quality possible?
This also extends to
the software. Pure Vinyl is designed (leveraging our more than
decades-long, in-house expertise in developing audio analysis and signal
processing software) from the bottom up to painstakingly preserve
all of the sound quality captured by your audio interface. This
goal can't be accomplished without the proper care and attention
Here are many
features of Pure Vinyl not found together in other software:
- Pristine, 64 bit double-precision
floating point internal signal path for no added distortion
- Built-in music server for
automated playback of music tracks from your iTunes music library
- 64 bit internal precision upsampler
for CD quality audio tracks, play at up to 192 kHz 24 bit through high quality
- Built-in two-way
crossover (can be used for subwoofer biamping), with adjustable
time alignment, slope and frequency
- Record to choice of
file formats at 44.1/48/88.2/96/176.4/192 kHz, 16/24/32 bit,
optional Apple Lossless Compression
- 64 bit sample rate converter
(SRC) for creating CD format audio from high-resolution source file,
exclusive Channel D design** (see this page for comparisons with other SRCs)
- 64 bit SRC can be used
to mirror to a second, CD format file, while simultaneously recording
- Adjustable, noise shaped
dithering for SRC / conversion to 16 bit format
- 64 bit RIAA vinyl compensation
curve, for live monitoring or file playback, accurate within a small fraction of a dB
- Library with choice
of dozens of customizable correction curves, for playing pre
- 1955 recordings
- Adjustable Noise Gate:
automatically pauses recording and locks when music stops (such
as stylus lift)
- Precision signal level
metering with RMS, RMS balance, peak, peak histogram and peak
- Controls for channel
swap, mono, polarity inversion, precision balance trim
- Unique*** "scratch
- style" grab and spin editor uses "vinyl" images rendered from the audio
- Adjustable (frequency,
slope) high-pass "rumble" filter
- ZEPHRR® zero-phase
rumble reduction filter for track rendering, slope up to 96 dB
- Nondestructive track
editor and pop and click editor, with automatic peak detection
- Split recording into
tracks for making CD compilations, iTunes, etc. digital jukebox
- Fun, animated spinning
"virtual vinyl" image during playback re-creates the
experience of seeing that spiral-scratch disc spin
- Low Latency NetSend feature for distributing
high-resolution (up to 96 kHz / 24 bit) audio to other Mac computers
Note: all updates to
Pure Vinyl have been provided free of charge, even to those
who originally purchased an activation code for Version 1.0.
*Everything affecting the audio
quality of Pure Vinyl has been carefully designed and validated;
we didn't simply "bolt together" generic pieces of audio
software from other sources.
**Other software running on the
Mac may use Apple's QuickTime routines for sample rate conversion
(SRC) / pitch alteration, etc. While that's easier on the software
developer that chooses to use QuickTime, the quality of QuickTime's
audio conversion routines have been regarded unfavorably, even
in Apple - sanctioned audio forums. The AudioUnit SRCs available
in Mac OS X 10.5 Leopard provide an improvement in quality over
QuickTime; see tests of SRC software on our site and elsewhere. Despite this, we still use our
own well-tested 64 bit SRC design.
***U.K. Patent #2454106. U.S. patent pending.
|I purchased an
activation code but can't find the Registration tab.
Registration is done within the Pure Vinyl Recorder application
|The Pure Vinyl editor quits unexpectedly
when opening a resampled file or rendering tracks.
The resampled Album Name (PV)
or Album Name (CD) file must be in the
same location as the Album Name.plist file (created by Pure Vinyl
Recorder where the high-resolution (Raw) audio file was saved). If you want to move the
file(s) to another location, they
should be moved as a group, at least until you are finished editing / rendering the CD format tracks.
If you have already tried to use the Editor
with a resampled file placed in another location, the Pure Vinyl music catalog files may have been
corrupted and should be removed before continuing. The Pure Vinyl Music Catalog.plist and
Pure Vinyl Music Catalog44k.plist files located in
Users/username/Music/Pure Vinyl/Track Lists and Vinyl Images, plus the folder with the name of
the album in Users/username/Music/Pure Vinyl/Track Lists and Vinyl Images/ should be moved to the Desktop
|The Pure Vinyl editor freezes for about a minute
with the beachball cursor when setting the lead-in for the first track.
This can occur sometimes when seeking near the
beginning of a Losslessly Compressed recording. Use the left / right keyboard arrow keys instead of
manually spinning the vinyl to set the lead-in for the first track. The keys will move (when in Mark-IN or
Mark-OUT mode) the playback
position by one revolution of the disc (1.8 seconds for a 33 1/3 RPM album), or fine-tuned by depressing the
Command or Caps Lock keys. Once you have set the lead-in coarsely (click M-IN in the Edit panel) the position
can be fine-tuned by spinning the disc manually.
|The Real-time sample rate converter
isn't saving music.
Because of certain optimizations in the software,
the real-time sample rate converter of the Recorder must be used with the RIAA filter option.
If you want to use the real-time resampling with
a conventional phono preamp setup (RIAA correction in the preamp), a work-around is to
create a Custom Setting for the Vinyl Correction curve with turnover points outside the audio
frequency range (Rumble Filter 20 Hz, Bass 0.5 / 0.5 Hz, Treble 20000 Hz, Bass Trim -6 dB).
|I launched Pure
Vinyl Recorder, but the meters don't respond, even though I'm
that your audio interface is functioning properly.
Quit Pure Vinyl. Open Apple's Audio MIDI Setup application (in
/Applications/Utilities) and insure that your audio interface
is selected as both the Default Input and Default Output device.
Try playing some music from iTunes. If the audio interface is
functioning correctly, you should hear playback from iTunes.
interface doesn't appear in Audio MIDI Setup, there is a software
or hardware fault with the interface that must be corrected before
proceeding. Consult the documentation for your audio interface
|I launched Pure
Vinyl Recorder, and it quit after briefly showing the main window.
behavior may occur with single channel (mono) audio input devices
that also don't have an output. A good example of this is the
external iSight camera. To correct the problem, open the Audio
MIDI Setup panel (in /Applications/Utilities) and select an audio
device for the Default Input and the Default Output (both inputs
and outputs) with two or more channels, such as the built-in
audio, or another external audio device.
|There's an odd
delay between when I start the audio source (place the stylus
on the record) and when sound comes from the monitor output.
Will this affect the recording?
Vinyl Recorder uses a large sound input buffer that causes the
"latency" you are experiencing. A large sound buffer
serves as extra insurance from skips in the sound as the recording
is saved to disk. It is not cause for concern and doesn't harm
the recording quality.
amount of latency might be a problem for multichannel studio
recording (overdubbing), but doesn't cause problems with two-channel
audio transferred from pre-recorded sources (or when recording
live sources without needing overdubbing).
benefit of the latency is that it will decrease the susceptibility
of your sound system to audio feedback between the loudspeakers
and turntable, if monitoring a vinyl recording at a high listening
If I open a song in an iTunes playlist and play it through pure Vinyl,
when that song ends instead choosing the next song on that playlist
it chooses the next song on that album and continues on from that
point. Is there any way to get it to play through a playlist?
Use the "First or currently playing" option in the iTunes control dialog in
Pure Vinyl, and sort the playlist by track number in iTunes, using the title
bar of the list in iTunes.
If you want to manually select the
next song to play within a playlist, just double-click
the song in the playlist before the one you want to be the "next" track to play. Then, Pure Vinyl will
increment your choice and pull the next track from iTunes. If using this method,
be careful to first reduce the playback volume to zero in iTunes (with the
volume slider); otherwise, iTunes will then play the music (possibly quite
loudly) directly through your audio interface.
You may also download
and use the Preview Release of Pure Vinyl 3, which has complete iTunes jukebox support.
|I recently upgraded
to iTunes 7. Now, Pure Vinyl editor quits unexpectedly when it
calls iTunes to add track information tags, or when I use Pure
Vinyl to create 45 RPM "singles."
installing iTunes 7, wait until iTunes has finished scanning
your music library for gapless playback, and adding album art,
because iTunes will be relatively unresponsive at that time.
When iTunes has finished with those tasks, quit and relaunch
iTunes and Pure Vinyl.
|I Installed the
Pure Vinyl Update on my Mac and the update won't run.
From your email you've
indicated that you're running Mac OS X 10.4.10 on an Intel Processor
Mac. There is a known problem with this OS X update on Intel
processor Macs, causing audio devices to stop working. This problem
isn't caused by Pure Vinyl.
The solution is to update
to Mac OS X 10.4.11 or later, or to download and install the
OS X 10.4.10 v1.1 Combo Update from Apple from their OS support
Try Pure Vinyl 3.1 FREE for 15 Days!
Mac OS X 10.5.8 or later (including Lion / Mountain Lion); G4, G5 or Intel CPU.