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In Reply to: RE: High Resolution - Fact or Fiction? posted by b.l.zeebub on April 09, 2014 at 06:52:25
We do a lot of recording at higher bit rates- 24 bit 88KHz is common (this can be easily divided down to Redbook).
When you record at higher rates you sure don't need that brickwall filter. By reducing phase shift in the audio passband there is an immediate improvement in sound, even if the final output is Redbook.
Of course, the highest bit rate we have used is still no match for the LP (we have an LP mastering operation on site in the studio, see the link) in the resolution department. But I have to assume that for this thread that is getting off topic.
Follow Ups:
"Of course, the highest bit rate we have used is still no match for the LP (we have an LP mastering operation on site in the studio, see the link) in the resolution department. But I have to assume that for this thread that is getting off topic."
What do you mean by no match for the LP?
Give me rhythm or give me death!
We've seen that plenty of times.
Of course, if an LP is done in a sloppy fashion, that is the problem with that particular LP, not *all* LPs. People often exercise a Hasty Generalization in this regard...
Something most people don't know is that if you have a good lathe cut, its devoid of surface noise- all phono sections will have more noise. The noise comes in from sloppy pressing practices. One house that is exceptional (IOW state-of-the-art) is QRP in Salinas, Kansas. They have done work to their pressing machines to kill vibration as the LP is cooling, and they have noise floors similar to the lathe cuts. They can be so quiet its spooky!
Obviously we do analog and digital recordings side by side. We have yet to have a client prefer the digital presentation- the differences are pretty obvious.
Or are we talking about something that requires a subjective appraisal?
Give me rhythm or give me death!
So far all the talk I see bandied about suggests that resolution is a subjective term. There are of course the specs:
You can suggest resolution in the digital world with bits and scan frequencies- generally speaking the higher the better.
With analog its a different animal- bandwidth, noise, distortion all play a role (and BTW, in a lathe cut you have more bandwidth and lower distortion that you do with digital, although in practical terms more noise as the phono reproducer will be the primary noise generator and the limit is about -90 db or so). This is because noise and distortion will block detail due to the ear's masking principle.
People are often surprised at how low the distortion can be on an LP; let's put it this way- its impossible to overload the cutter amplifiers. By the time they make about 10% of full power they will have toasted the cutterhead. And the cutterhead can make nice clean cuts that no cartridge would ever have a hope of tracking long before its overloaded.
I can't say for certain that the things I've listed are indeed the whole story- for example although you loose phase information with less bandwidth, things can still sound pretty good if it only goes to 20KHz before it rolls. We can put 30KHz on our lathe cuts easily enough and it plays back fine on a modest turntable. 20Hz on the bottom end isn't the limit either. The mechanical resonance of the pickup is the limiter there.
Consequently I go for 'subjective experience' even though the specs favor analog by about 70%. I just don't think the specs that we use today tell the whole story. If they did, we would be able to tell how a product sounds just by looking at the paper. But that is a topic for a whole 'nuther thread!
Hey Ralph, got an off-topic question for ya, but first... Your Ampex 351 and Scully lathe are taking me way back! My old friend George Johnston (long passed away) in Oshkosh, WI used that same stuff! As a high school & college kid, it was always fun to go over to his house and talk about recording and watch him run his lathe. Good times! He inspired me to get into the audio biz.
Anyway...
There used to be companies like KM Records in New Jersey which would do "one-off" or short run (100-200) LP pressings. Does anyone do that anymore? Just curious. Thanks.
:)
A lot of local bands do short run. Our first LP (Thunderbolt Pagoda) was 360 copies. So the pressing houses do that, but the pricing is rough- generally you will barely break even with an LP around 300 copies assuming you have them priced right.
Interesting, it's always good to hear from someone who has detailed and specific knowledge.
The LP mastering hardware looks interesting. Does it get used much?
Remastering an early Michael Yonkers LP right now. Doing some independent releases after that.
The funny thing is that since the mid '70s the vast majority of record cutting lathes run the signal through a digital delay running at 14 or 16bit 48k.
The preview head does use a digitized signal but has nothing at all to do with the signal chain driving the cutterhead.
The idea is you take the output of the preview head (which is an additional tape head on the tape deck, about 2 seconds ahead of the main playback head) and create a digital output from it.
This output is then used to drive the electronics that operate the thread drive motor which advances the cutterhead across the LP. In this way, if there is a loud sound like a bass drum whack, the cutterhead makes room for it one rotation in advance so that the resulting groove will not overcut a previous groove.
This technology has indeed been around for a while and is known as 'variable groove spacing' or the like. The RCA Dynagroove system was an early analog version of the same idea.
Here is what a mastering/cutting engineer has to say on this (they modified their lathe to get a true analog path):
"Marino describes, “The basic setup for cutting records is that you have an analog playback machine and the playback head feeds the signal to the cutting lathe. To cut a record properly, the computer in the cutting lathe needs to have a ‘preview’ [of what’s coming next as it’s printing], which is typically done via digital delay. The lathe gets two signals — the preview and the digitally delayed signal — and it’s the delayed signal that gets cut to the lacquer, which is not ideal.” "
Below link to article.
-And the better operations (RTI, QRP are examples) don't do it that way as mentioned in the article- they maintain an entirely analog signal path to the head.
There is no good reason I can think of to delay the signal in the digital domain, not if you are coming off of analog tape (unless you just don't want to pay for the machine work to do the preview head-nest). If the master file is digital then that is a different story.
We solved the problem by using an computer to store advance information of the LP side. So we have to play the source for it without the lathe running. Then we start over again, only this time the information gathered by the computer is used to drive the advance threads.
BTW Chris at Sterling is a customer of ours.
for providing a simple and logical explanation as to what many of us hear.
I just shake my head wondering why guys like "Monty" Montgomery miss the boat and would rather play with their oscilloscope attempting to *debunk* the value of high resolution recordings.
Ralph seems to be saying that one doesn't need hi-rez playback to get the advantage of a hi-rez recording. Maybe he could clarify.
I think that's what most people want to know when they are paying extra for hi-rez downloads.
I did point out that on the record side you don't need a brickwall filter anymore with a higher scan frequency (although there is still a filter, just not so severe) and that there is a benefit even if you are only operating on Redbook in playback.
But if you playback at the higher bit rate of course that is even better, assuming your DAC really is up to it.
When we are mastering an LP from a digital file, we encourage the client to give us the highest resolution file they have- it makes for a better sounding LP.
I have to say at this point I really don't understand why someone would record at 44Khz/16 bit when there is so much hardware that can do better than that for very little cash! If you think about it, 44Khz 16 bits was created as a standard at a time when the Apple 2 was king. How quaint, how archaic. Look at how far computing has come in the last 34 years and we are still using that standard??
Absolutely! Digital audio has always been driven by the storage technology of the day.
I work in the IT field and back in the early 80s, data storage cost almost $500/megabyte. I remember upgrading our mini computer to a multi-platter 75MB removable drive that cost about $35,000.
I just finished my daily backup of about 10 GB of personal and business files to a $30 USB nano drive the size of my thumbnail.
I think that's what most people want to know when they are paying extra for hi-rez downloads.
I know because I have heard and own quite a few! That's the only thing that matters to me.
Not every recording, however, labeled as "high rez" is necessarily better than a lower resolution version, but most in my collection certainly are.
YMMV.
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