33 vs 45 speed quality

There are a couple of other aspects worth mentioning. The higher rpm does better with more highly modulated passages, offering more articulation in the bass and greater dynamic slam, and allowing the entire record to be cut somewhat "hotter", improving the S/N ratio. (Provided, of course, that your cart and arm can keep up and take advantage of it, as well as your phonostage.) Another difference, not necessarily an advantage, is that what background groove noise you do hear will be in a higher frequency range at the higher rpm, which subtly alters the perceived character of the listening experience vs. the same recording cut at the lower rpm. But perhaps the dominant difference in a lot of instances could be that the 33 and 45 rmp releases of the same material may not have been mastered together by the same people at the same time in the same facility, in which case all bets are off and there's no reason not to expect them to sound noticeably different.

Eldee: Since I don't buy 45 rpm audiophile remasterings, I can only go by what I hear with regular 7" singles vs. the same cuts as album tracks. But the theory isn't unlike that with magnetic tape, where there can be greater dyanamic and frequency range and a better S/N ratio at a higher record/play speed. (I haven't heard a 16 rpm record in years, and never on a good machine, but I'd imagine they would be decidedly low-fi at best.) Due to the more "physical" nature of tracing a groove with a stylus and the tracking errors inherent in most phono playback arrangements, I'm sure the point of diminishing returns (i.e., practical problems) with increasing speed probably sets in earlier with vinyl than with tape (I doubt the kind of speed displayed by computer data-storage tape transports of yesteryear could be approached by any needle and groove arrangement). But the "stretched-out", "big" groove on a 45 demonstrates that at least to a point, the higher rpm system also makes for a hardier medium, sailing through damage that would render an LP unplayable, though not all of this is because of speed per se. BTW, what leads you to think that if a niche audiophile standard for vinyl disks were adopted, it could sound better for encoding *greater* bass amplitude on the record, rather than less? (Well, you don't actually say that, only seem to imply it.) I have no experience with the DBX system, but I assume it also used compression/expansion? Audiophiles would never go for that, and I'd think probably with good reason...

Well, most master 'tapes' these days are digital, and the ones from the 'golden era' that audiophiles like to buy remasters of largely predate Dolby and DBX. I can well understand how a compression/expansion scheme could aid LP playback in theory, but since modern carts/arms are capable of tracking pre-EQ'ed but uncompressed records without mistracking, and since no analog compression/expansion system can be totally transparent and without losses, I still doubt this would fly in the audiophile marketplace. Personally, I think if you were going to go to the trouble of developing a whole new encode/storage/decode protocol just for audiophiles (this will never, ever happen), you might want to consider an optical analog system.

Eldee, I think we might be blurring a few different topics: Compression (or gain-riding) applied during the recording, mixing, or mastering processes for artistic purposes (to enhance the desired sonic effect); compression (or gain-riding) applied during the recording process for technical purposes (to prevent overload during recording); and compression applied during the mastering process for technical purposes (to prevent overload during playback). And then there's compression applied during radio broadcast for both technical and 'artistic' purposes. I view all of these as being different from complementary compression/expansion, which are mainly used during recording as part of noise-reduction schemes (Dolby A, DBX) and aren't supposed to limit the dynamic range of the resulting master tape (though it may still undergo compression when mastering the record, or CD for that matter). There's also the rather arcane distinction between peak-limiting and compression, which as far as I can tell seems more of a definitional, quantitative one than subjectively qualitative. Anyway, I agree that most recordings we listen to, audiophile pressing or not, probably make use of compression for at least one of the first two reasons I listed at the top -- compression and EQ are the best friends of the recording engineer, producer, and mastering engineer.

Since we're already this far off topic...Until I bought my Alesis MasterLink, which performs both compression and peak-limiting, I probably would've described peak-limiting the same way you have. Apparently, I hadn't thought about it a lot in relation to compression, technically speaking. The compressor has all these adjustable parameters:

Threshold (level relative to full-scale 0dBfs the compressor begins to affect the audio)

Ratio (of input level to output level of the compressed audio)

Make-up gain (applied after the compressor to compensate for the level lost in the compression process)

Attack (time the compressor takes to begin affecting the audio after it's risen above the threshold)

Release (time the compressor takes to stop compressing the audio after it's fallen below the threshold)

Knee (controls the way the compressor behaves around the threshold by varying how quickly it ramps up to the full selected compression ratio -- a "hard" knee applies the full selected ratio at the selected threshold level, while "softer" knees progressively take effect beginning a selected number of dB's below the selected threshold level, increasing the applied ratio until at some level *above* the threshold it is fully equal to the selected ratio)

There are also controls determining whether the compressor is keyed to peak or RMS input levels, of the left or right or both channels, plus for what the meters measure. Fancier compressors than this one can have multiple frequency bands of compression per channel, each with independently variable parameters.

The peak-limiter in the MasterLink doesn't have all these adjustable parameters (just Threshold and Release, plus an adjustable Output level control, for if you want to preset the maximum output at something less than 0dBfs; make-up gain is applied automatically, equally and in opposition to the selected threshold level), so it's simpler to use. And because it's all-digital, it's able to "look ahead" and begin progressively reducing gain in advance of a peak exceeding the selected threshold (similar to the Knee control, but fixed), for a smoother dynamic compared to traditional analog peak-limiters. But conceptually speaking the two functions involve all the same processing.

According to Alesis, a traditional peak-limiter "is typically thought of as a compressor with a high ratio setting". Due to the look-ahead feature of theirs, they say it functions with essentially an infinity:1 gain-reduction ratio. (I presume the attack time must also be fixed at zero and the compressor keyed to peak level for both channels.) In other words, any signal exceeding the selected threshold level at the input is held to that threshold level at the output -- and that threshold level could be either high, low, or anywhere in between. So peak-limiting is compression with less potentially varied, more narrowly defined behavioral parameters.

Csmithbarc: Sorry man, I'm done! :-)