Playback and Recording (Vinyl)
Why invest in an obsolete, 50+ year old music medium?
- Used vinyl is often extremely inexpensive - 50 cents to two dollars a disc is somewhat common. Vinyl is a very cheap way to expand your collection in older artists that you cannot justify spending $15/CD on listening to.
- Some albums have simply never been released on CD.
- Some album art is better suited to the larger scale of LP covers and sleeves.
- The mastering of an original LP release is often considered superior to a CD remaster of the same release. This can be for any number of reasons, including:
- Increased use of compression and limiting on the CD release, reducing dynamics
- The master tapes have often degraded in the time between the LP and CD releases
- The equalization and even mixing of some CD releases is radically different than on the LP releases. For instance, many Zappa LPs have had entire drum tracks replaced for the CD release.
- Properly maintained vinyl is of a surprisingly good quality and is often not objectionable.
Why not vinyl?
There are several disadvantages.
- Vinyl is particularly finicky to maintain and easy to damage.
- Surface noise, while often inaudible, will always be present, even on a brand new LP.
- The quality of a record often cannot be determined until you play it, increasing the risk of the purchase. Even brand new, sealed LPs can have significant pressing and warping problems.
- Not portable.
- Investing in a reasonable vinyl system is hundreds to thousands of dollars more expensive than investing in a reasonable CD/computer system. Financially, any benefits of the cheaper media must be compared against the amortized cost of the equipment needed to play and maintain it.
- There is also a not insignificant running cost in playing LPs. The stylus does wear out, and top class cartridges use stylii costing several hundred (or even thousand) dollars. Playing one LP with an audiophile cartridge can easily cost over a dollar in stylus wear.
- Records are large and heavy. Transporting them correctly is logistically difficult.
- Many record stores have a considerable markup on used LPs and it may be hard to find records for cheaper than $10 in some stores. This makes it much harder to completely justify vinyl on a financial basis.
- Some vinyl has a very high collector's value which makes it nearly impossible to locate for prices cheaper than CD.
Note that a lot of this info is currently US centric.
The "market rate" for LPs depends primarily on the collector's value. Mass-produced and unpopular LPs will not cost more than a dollar. Original pressing Beatles LPs are usually over several hundred dollars. Jazz records tend to be very expensive. Classical records tend to be quite inexpensive. Rock, blues and electronica lie somewhere in the middle.
Depending on how clued the store is to the by-the-book market prices of vinyl, prices can range anywhere from 50 cents on up. Record stores tend to have the highest prices and charity stores the lowest, but there are always exceptions.
- Many cities have local record stores that specialize in certain genres. Check your yellow pages and local music listings for ads.
- Half Price Books (US) tends to have extremely good vinyl selections. Vinyl is not transferred between stores, so the quantity/quality varies widely even by the neighborhood.
- Goodwill, Salvation Army, and other charity stores often have good deals on vinyl.
- The Austin Record Convention http://www.austinrecords.com/ has a very, very large quantity of LPs. Biannual. Similar conventions exist in many other large cities.
Turntables vary widely in price, construction and age. Audiophiles will categorize the subjective qualities of a turntable on the following metrics:
The plinth is the base of the turntable, on which the platter (and usually the motor) rests. The basic function is to isolate the components mechanically from the base of the turntable and from each other.
Construction styles vary:
- No isolation whatsoever (solid box). For very cheap turntables.
- A box, often wooden, holding a metal plinth supported by springs. Usually found only on vintage turntables.
- A plinth of multiple levels, each level isolated from the other by some rubber-like substance. In some form or another most audiophile turntables use this method.
- Physical separation of the turntable components from each other, and individual isolation of each component from the ground. Certain very expensive turntables use this method.
There are few objective criteria for plinth design. Isolation issues can be resolved through the use of additional isolation placed underneath the turntable. Build quality is important and may be lacking, even for audiophile turntables.
The stick-shaped part of the turntable.
- They hold the cartridge on top of the record, keeping it properly aligned, and carry the wires down to the plinth.
- A counterweight is placed on the back to reduce the force of the needle on the record to very low levels, usually equivalent to an effective mass of roughly one gram.
- A force, the anti-skate force, is applied to the tonearm, pulling it outwards from the center of the disk, to counteract forces during playback that pull it towards the center.
- The tonearm must be lowered slowly onto the disk to prevent damage to the disk or the stylus. All quality turntables include a mechanism, usually hydraulic, to slowly lower the tonearm.
Key differences between tonearms include:
- Build material
- Shape (S-shaped or straight)
- Linear tracking or angular tracking
- Degrees of freedom on the mounting
- Antiskate force mechanism
There are several objective differences between tonearms:
- The mass of the tonearm affects the resonances of the playback system. The mass can sometimes be incompatible with the mass of the cartridge and the compliance of the stylus, leading to an excessively high or low resonant frequency that induces skipping or rumble, or can negatively affect low frequency performance.
- Tracking errors, representing angular deviations between the stylus and the record groove, are present with every tonearm, and different designs use different approaches. Linear tracking arms, in theory, have zero tracking error. In practice they require a motor to move the tonearm, with some known error in correct positioning, as well as some vibration. S-shaped tonearms are shaped to reduce tracking error but (XXXX list issues).
- XXX high frequency effects?
- Counterweight markers are notoriously unreliable and a scale is often employed to get a correct measurement of the counterweight setting.
The platter is the rotating part which supports the vinyl record while it is played. The platter should ideally be acoustically dead, ie. it should not "ring" like a bell. Platters that ring store energy and release it slowly back into the record, causing loss of fine detail.
Belt drive turntables use a small motor turning fairly rapidly, and a belt then transfers the power from the motor spindle to the platter. On some models the motor sits outside the platter and the belt runs around the outer edge of the platter; on others the platter is in two parts with an inner spigot for the belt, with the motor sitting between the spigot and outer edge of the platter. There is no significant advantage to either arrangement, with the possible exception that when the motor is external to the platter it can be sited a long way from the path of the pickup cartridge, and therefore potentially reduce the danger of hum pickup by the cartridge from the motor.
The belt (usually some form of rubber or similar material) provides excellent decoupling so that motor bearing noise is not transferred into the platter (and thence to the LP).
The motors used are usually synchronous AC motors whose speed is determined by the frequency of the mains supply. Some more expensive belt drive turntables include a sophisticated power supply which generates an AC signal even cleaner than that provided by the mains.
Since the motors on belt drive turntables do not have much torque, and because the AC frequency might vary slightly, stable rotation of the platter is achieved by the use of high mass platters that provide a "flywheel" effect to smooth out any variations. A consequence of using a high mass platter and a low torque motor is that start-up speeds are rather slow, and hence belt drive turntables are not really suitable for broadcast or DJ use.
In a direct drive turntable, the central spindle in the platter is an extension of the axle. So the motor itself sits directly underneath the platter, and rotates slowly at the required vinyl record playback speed (ie. 33.3/45/78 rpm). Such motors are high-torque servo-controlled DC motors, and the turntable includes some means of measuring the rotation speed of the platter so that it can adjust the motor's speed to keep it steady.
Since the platter is directly attached to the motor, it is not well decoupled from any bearing noise. However, since the motor turns at a slow speed, the bearing noise is very low frequency and therefore will not cause audible degradation.
Idler Wheel Drive
This type of drive mechanism was traditionally used on cheap autochangers, and involves a small motor running at fairly high speed (like in a belt drive turntable). But unlike a belt drive turntable, the power is transferred to the platter by means of a wheel (usually rubber) sitting between the motor spindle and the platter edge. The wheel offers far less decoupling, and so motor noise is transferred to the platter. What's more, because the motor rotates at high speed, this noise can affect the audible frequency spectrum.
That said, there have historically been some successful high quality idler wheel drive turntables. Perhaps the most famous is the Garrard 301.
Internal Wiring and Power
From the forums.
- What sample rate to record with? (thread thread) In general 44.1khz will work fine. There are not significant reasons to choose either 44.1khz or any higher sample rate. Some postprocessing tools for vinyl recordings only operate at 44.1khz. Additionally the dynamic range and distortion specifications for many sound cards are better at 44.1khz than at higher sample rates.
- What bit depth to record with? (thread) Similar to the sample rate question above. In general 16 bits actually does work well. It's a common misconception that the quantization noise will significantly raise the noise floor of the recording; as long as the signal peak is -10dbFS or higher it is not an issue. If you plan to perform a very large amount of digital processing on the recording, the rounding errors could build up sufficiently that they impinge on the background noise level of the vinyl. In that case the recording should be made at (or converted to) 24 bit resolution prior to the processing stages to reduce the effect of rounding errors. That said, you would need to do a very great deal of processing before a 16 bit recording of vinyl became degraded in this way. A few passes of EQ, noise reduction, amplitude adjustment, etc. isn't going to bring the quantisation noise up above the vinyl noise floor.
- How low of a frequency can LPs produce? (thread) The common wisdom is that they don't have much below 60hz, but there is evidence that the signal extends as low as 20hz and possibly lower on some LPs. Note that low bass on vinyl records will be mono, but this is not a problem because low bass is non-directional. (The reason for this is that low bass signals cause the largest groove excursions, and of course the vertical (out of phase) component of the groove must never be so great that the groove rises above the surface of the record, so the out of phase component of the low bass is removed when mastering for vinyl).
- How much bandwidth is on an LP? (thread) This is a hard question, because the dynamic range has to be considered and it is frequency-dependent. It is almost certainly lower than CD, and certainly far lower if the theoretical bandwidth limits of the CD medium are considered, rather than the digital specifications. Although some sort of signal above 20kHz can be recovered from an LP, it is highly unlikely to be related to the programme material; in other words it is noise. The majority of LPs probably contain nothing of significance above about 16kHz.
- What recording level should LPs be recorded at? (thread) As high as possible without clipping. -3db is usually safe and some sound cards may distort if driven past that. If you are recording on a sound card with a good noise floor (100db or greater) then you can go as low as -18db without ill effects.
- How to remove sibilance? (thread)
- How should mono LPs be recorded? (thread)
- What are some examples of good and bad vinyl rips? (thread thread thread thread)
- Can/should LPs be ripped faster than real time, ie at 45rpm or 78rpm? (thread) No.