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The best way to learn to discern quality differences in pres and converters?
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jtg
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16th December 2006
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The best way to learn to discern quality differences in pres and converters?

Im wondering what some good ways are to evaluate the quality of different preamps and converters. To an untrained ear, are there certain "challenges" you can subject them to that will highlight the differences and shortcomings?

Aside from just listening to a mix that youre very familiar with, Im wondering what a good way to tell is. I dont have much experience with a lot of different products so these differences arent obvious to me yet. I dont know what to listen for or how to make weaker components fall on their face.
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16th December 2006
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Quote:
Originally Posted by jtg View Post
Im wondering what some good ways are to evaluate the quality of different preamps and converters. To an untrained ear, are there certain "challenges" you can subject them to that will highlight the differences and shortcomings?

Aside from just listening to a mix that youre very familiar with, Im wondering what a good way to tell is. I dont have much experience with a lot of different products so these differences arent obvious to me yet. I dont know what to listen for or how to make weaker components fall on their face.
A perhaps revealing test for A/D-D/A paths is to take a well known test signal, and run multiple passes through both the A/D- D/A loop. Over enough cycles any errors will accumulate and become easier to hear. Trying to apply this to just the A/D or D/A will be limited by the perfomance of your reference conversion.

Preamps are a little more difficult make useful comparisons by just listening (some will surely disagree) but microphones and loudspeakers routinely deviate from flat, linear performance an order of magnitude more so it's not clear what you're actually hearing in listening tests. A preamp with an error that happens to improve a flaw elsewhere in your chain is only useful in that specific combination.

I believe the difference between good and great preamps is much much smaller than the difference between good and crap, if that makes any sense.

JR
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16th December 2006
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Im wondering what some good ways are to evaluate the quality of different preamps and converters.
I agree with John's advice. This is not as complicated as some might believe. The goal of all audio devices - other than those that add intentional color - is to pass the signal as cleanly as possible. This is what audio test equipment is for! So the single best way to evaluate any gear is to measure it, or at least read the manufacturer's specs. In lieu of measuring or reading, John's idea to record multiple passes is excellent.

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Just listen to the latest buzz...


And then do the opposite.

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16th December 2006
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The goal of all audio devices - other than those that add intentional color - is to pass the signal as cleanly as possible.
I actually could not disagree with that MORE.

The goal is to translate the "real" "in room" experience as transparently to playback systems as possible. Which is very different than passing test tones accurrately. Sometimes, it's neccessary to "color" to make it more transparent sounding--meaning similar to the experience of being in the room.

Example. A woman with a gorgeous voice is sitting next to you on the piano bench belting it out...2 feet from your head. Amazing tone. You're gonna tell me that some test quality super accurrate mics into Hv3s is going to more accurrately simulate that sound on two playback speakers? As compared to an old 251/Neve--neither of which apparoaches passing test signals as accurrately as the, say Earthworks set up? No doubt if it were a test tone generator, and a computer analysis app, rather than a human voice and another set of human ears...the "clean" setup would "win".

I give little cred to mic graphs and test tones. You want to know the difference in converters? All converters suck. Start with that assumption. Get some name brands, and make a record with it. Not a track...a whole record. Does that record sound better than the one you made last week with your built in converters? If yes, converters are your bottleneck. If no...then either A)the high dollar converters aren't better or more likely B)you have a greater bottleneck in your recording/music.

Identify your bottleneck. Find out how much it will cost to address it. Don't just read that you need preamps and converters and this and that...start with the problem before looking for solutions. ie "my bass guitar just doesn't sit right in the mix" ....or "I find that my electric guitar tracks have this weird sizzle and need a lot of EQ to minimize it"...
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Originally Posted by popmann View Post
I actually could not disagree with that MORE.

The goal is to translate the "real" "in room" experience as transparently to playback systems as possible. Which is very different than passing test tones accurrately. Sometimes, it's neccessary to "color" to make it more transparent sounding--meaning similar to the experience of being in the room.

Example. A woman with a gorgeous voice is sitting next to you on the piano bench belting it out...2 feet from your head. Amazing tone. You're gonna tell me that some test quality super accurrate mics into Hv3s is going to more accurrately simulate that sound on two playback speakers? As compared to an old 251/Neve--neither of which apparoaches passing test signals as accurrately as the, say Earthworks set up? No doubt if it were a test tone generator, and a computer analysis app, rather than a human voice and another set of human ears...the "clean" setup would "win".

I give little cred to mic graphs and test tones. You want to know the difference in converters? All converters suck. Start with that assumption. Get some name brands, and make a record with it. Not a track...a whole record. Does that record sound better than the one you made last week with your built in converters? If yes, converters are your bottleneck. If no...then either A)the high dollar converters aren't better or more likely B)you have a greater bottleneck in your recording/music.

Identify your bottleneck. Find out how much it will cost to address it. Don't just read that you need preamps and converters and this and that...start with the problem before looking for solutions. ie "my bass guitar just doesn't sit right in the mix" ....or "I find that my electric guitar tracks have this weird sizzle and need a lot of EQ to minimize it"...
And what exactly do you add to or subtract from the actual signal to make it more "real"?

Of course there is a place (or certainly a market) for the sundry enhancers out there. Translating 3-d sound field to a 2-d recorded medium then back to a 3-d sound field for playback leaves something to be desired. Stereo and other enhancements certainly improve that experience. While no one can or should claim perfection in the total process, individual circuit blocks can be made arbitrarily accurate. IMO any enhancements should be applied cognizently in their own circuit block, when and as is deemed beneficial. Of course opinions vary.

JR
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16th December 2006
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And what exactly do you add to or subtract from the actual signal to make it more "real"?
Agree with me on this...an Earthworks SDC is more accurrate than a U67. Now...how many vocal tracks in the history of pop music were done with Earthworks....and how many were done with a U67(or variation)? Why the descrepency?

What is the purpose of compression in recording? EQ?

I'll answer-- they are to minimize the side effects of recording-going under some assumptions about the playback system. The human ear hears things differently in a room than it does when the same thing is pumped though two speakers in the same room. The colors/filters/processes/circuits...are there in order to bring the same level of musicality to the recordings that exist in the room. Of course, they ultimately fail...but, they get us further than "clinically clean and pure reproduction" do, neccessarily.
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Quote:
Originally Posted by popmann View Post

The goal is to translate the "real" "in room" experience as transparently to playback systems as possible.
Yeah. IMO there's too much about "tone" in mic preamps. To me it's "does it make the track sound interesting and/or exciting?" which probably has a lot to do with dynamics, headroom, transients and a bunch of other stuff like that.
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Quote:
Originally Posted by popmann View Post
Agree with me on this...an Earthworks SDC is more accurrate than a U67. Now...how many vocal tracks in the history of pop music were done with Earthworks....and how many were done with a U67(or variation)? Why the descrepency?

What is the purpose of compression in recording? EQ?

I'll answer-- they are to minimize the side effects of recording-going under some assumptions about the playback system. The human ear hears things differently in a room than it does when the same thing is pumped though two speakers in the same room. The colors/filters/processes/circuits...are there in order to bring the same level of musicality to the recordings that exist in the room. Of course, they ultimately fail...but, they get us further than "clinically clean and pure reproduction" do, neccessarily.
In making music, or the variant making recordings, a great deal of nonlinear processing is involved to improve upon the reality that can be captured. Where I believe we may disagree is whether individual blocks within an audio path should be arbitrarily accurate with the nonlinear processing applied in a thoughtful manner "only" in dedicated effects circuit blocks, or whether each circuit block is fair game for euphonious deviation from the classic straight wire with gain.

Use of favored microphones due to differences in pattern, frequency response and other more subtle differences has it's place, not unlike EQ'ing a waveform to taste. Appropriate application of dynamics processing also has it's place as a black box effect with obvious utility.

This thread was about evaluating mic pre's and A/D convertors. I vote for flat and linear. If you prefer otherwise that's your prerogative.

JR
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17th December 2006
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Well, I don't know that we disagree on a personal level...my Hv3 and Kurzweil conveters are gonna be on the clean side. But, mine is not the only aesthetic. An all API/Apogee production has a "sound"--one that you won't get any other way, IMO.

Mine was an objection of theory. Concept, if you will. Pointing out that the goal, IMO, is not served well with test tone information...it would be easy if that were the case--we'd all just buy the "best" we could afford and move on. It wouldn't be subjective.

Anyway...carry on. Sorry if I derailed.
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Easy answer to this question... at least get a great converter set for your main tracks... At some level the various great converters are very close to each other... Get a as many pairs of great pres with the colors/clarity that you need... and get some different mics... biggest difference of all... cheers,
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Quote:
Originally Posted by Ethan Winer View Post
I agree with John's advice. This is not as complicated as some might believe. The goal of all audio devices - other than those that add intentional color - is to pass the signal as cleanly as possible. This is what audio test equipment is for! So the single best way to evaluate any gear is to measure it, or at least read the manufacturer's specs. In lieu of measuring or reading, John's idea to record multiple passes is excellent.

--Ethan
One of the few times I'm gonna have the temerity to disagree with Ethan, at least a little.

I've been reading manufacturer's specs since the early 60's and -- yes -- a lot of information CAN be had from published specs if you know how to read them [and, let's face it, a lot of us are far more artist than scientist], how to read between the lines and, crucially, if you can trust the manufacturer's testing methodology, thoroughness, and completeness of information. (Knowing a given unit has a frequency bandwidth effectively flat from 20-20kHz is nice... but if you DON'T know that the unit also has hideous distortion or a high noise floor... you get the drift.)

If we could trust the thorughness, rigor, and -- let's face it -- honesty of all manufacturers, comparing by spec could be a very informative and important facet of the decision process -- but it would still be considerably less than all the information we need.

____________

Now, with regard to transparency vs color/flavor... for me, I want transparency, lack of color/flavor in ALL of my chain -- except where I don't -- IOW... I want my converters, mixers, power amps, my monitors and monitoring environment (HA! on that last) to be as neutral, transparent, flat as possible. But when it comes to mics and preamps and compressors.

While I like having some that are as neutral and accurate as possible, I also see the value of some that are characterful in a way that hopefully complements their subjects... but I like to keep these roles fairly clearly defined.

I'd love to have a channel or two of Neve or other vintage or boutique pre or strip... but I put some time in working on a nice old Neve board in the early 80s and I have to tell you that I'm not really a fan of the overall sound of the projects that came off that board. The "Neve sound" on a few elements of a mix, I like. But when you start stacking up all that character and color it starts turning into a real monolithic "signature"... not for me.

______________


Anyhow, a really interesting topic and a LOT of food for thought from everyone.
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17th December 2006
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One of the few times I'm gonna have the temerity to disagree with Ethan, at least a little.
I don't see any disagreement. I didn't say that manufacturers always tell the truth, or that they always report all relevant specs!

> I want transparency, lack of color/flavor in ALL of my chain <

Me too.

--Ethan
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> I want transparency, lack of color/flavor in ALL of my chain <

Me too.
yikes... a world without color is like a day without sunshine

what do you guys eat, plain rice?

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18th December 2006
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sometimes once you go back to your low end pres and converters and pick out what you dont hear can better highlight the differences.

good pres will also show up bad mics
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18th December 2006
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The difference is more apparent than I would have thought! I checked out some of those A/B comparisons of Black Lion modded 002s, wow what a difference.
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yikes... a world without color is like a day without sunshine

what do you guys eat, plain rice?

Well, let's keep this in perspective. The OP asked:

Quote:
Im wondering what some good ways are to evaluate the quality of different preamps and converters.
To my way of thinking, quality is the absence of artifacts, and implies a flat response with low noise and distortion. Now, had the OP asked what's the best way to add some "glue" or "color" to the signal chain, the answer would be very different!

--Ethan
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Originally Posted by Ethan Winer View Post
I don't see any disagreement. I didn't say that manufacturers always tell the truth, or that they always report all relevant specs!

...[snip]
I'm greatly relieved.

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18th December 2006
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Originally Posted by 11413 View Post
yikes... a world without color is like a day without sunshine

what do you guys eat, plain rice?


Now, now... Ethan quoted me a little out of context. What I actually wrote was:

Quote:
Now, with regard to transparency vs color/flavor... for me, I want transparency, lack of color/flavor in ALL of my chain -- except where I don't...
Of course, what I was getting at (aside from trying to hedge all my bets) was that I want to be able to pick and choose and control the color/flavor I insert into my recordings... and I want it to be as transparent/flat as possible the rest of the time.

Easy, huh?

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Quote:
Originally Posted by theblue1 View Post
Now, now... Ethan quoted me a little out of context. What I actually wrote was:



Of course, what I was getting at (aside from trying to hedge all my bets) was that I want to be able to pick and choose and control the color/flavor I insert into my recordings... and I want it to be as transparent/flat as possible the rest of the time.

Easy, huh?

Trying to sort this out, you appear to be saying you find some utility for a preamp adding euphonious coloration, but not all the time?

Assuming the OP is willing to entertain buying multiple preamps, do you have any specific advice for what non-linearities he should look for in his other than transparent path(s)?

As a designer I lean toward linear colorless electronic paths (perhaps a failure of imagination), but believe there may be a place for tweaking the mic preamp input termination as i expect that will interact with sundry microphones to generate audible frequency response variants.

While the microphone engineer probably designed the microphone expecting a nominal termination, altering that termination is not unlike applying eq and probably fair game in a studio where the result is what matters.

I would however suggest first acquiring a good clean reference path before getting too experimental.

JR
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18th December 2006
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Originally Posted by aussie_techie View Post
sometimes once you go back to your low end pres and converters and pick out what you dont hear can better highlight the differences.
I think you're right on.....at least when it coms to clean vs clean preamp.
In general, it's not always about the obvious tonal differences, but in the depth and detail of sound stage. Sometimes it takes recording of more than one track to really be able to notice obvious differences and sometimes they just aren't so obvious.

Quote:
good pres will also show up bad mics
That's why for some mics I don't want the absolute cleanest and clearest preamp. They accentuate the negative sonic attributes of some mics, such as edge, harhness, essiness, eshiness.

As for converters, while 'bouncing a track many, many times may reveal a build up of negative attributes, unless you plan on bouncing your tracks like that I think it's another theoretical point that has little bearing on the outcome - we don't hear theoretically. For instance, take a converter/box that uses some limiting. Bouncing a track with it umpteen times may result in crap, but it may have a pleasing effect on the original track.

It seems to me that the same people with the opinion that ***** is great and ***** sucks tend to forget that the "artifacts" in ****** are what make it sound pleasing to the human ear.

Then again, maybe it's just different preferences.
In all, when trying to judge between gear of relative good quality, that's what I think it comes down to.
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19th December 2006
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True, tubes are a good example. Everyone loves the sound of tubes, but they arent high quality by any means, its the small amount of harmonic distortion we like.

I would rather have preamps as a reference though and color the signal elsewhere, as some people have said.
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As a designer I lean toward linear colorless electronic paths ... I would however suggest first acquiring a good clean reference path before getting too experimental.
I agree. "Color" is easy to add later when mixing, and it doesn't have to cost a lot either. For the same reason it's often good to defer EQ decisions until mixdown, the same goes for added grunge and distortion. I mean color.

It's easy to dirty up a clean recording, but impossible to clean up a dirty track. And maybe this should be made clearer: Color is distortion in one form or another. It could also be a rolled off or accentuated high end. But it's usually distortion. You can get great distortion from a transformer, or a tube stage, or a compressor with a too-fast release time, or a tape-sim plug-in. What matters far more than the actual mechanism is the amount of distortion you apply. Season to taste and all that.

--Ethan
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If you are just starting out then I would just go with as clean as you can get. I myself like color, but you have to be careful with it. It might sound great with it solo, but as soon as you put it in the mix it may (or may not) work well. It really comes down to experience with these kinds of things. That to me is the difference between a good eng and a GREAT eng. He can pick these knowing what the sound is going to be. A good example of this is the LA610 I have. It sounds great on just about everything, but if I record all the tracks with it the sound really does not translate very well. SOMETIMES

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a sidenote about color i'm just beginning to understand: you dont wanna add harmonics to schmotz and crap you want to eq out later... so if you're banging stuff down to tape (or any other method of adding harmonic content) you want to remove all the crap (preponderant energy) from the sound or you'll just be making the crap harder to remove.. because it will be bigger and have more harmonics...

this is the argument FOR eq'ing to tape.

HMMMMM
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Quote:
Originally Posted by jtg View Post
Im wondering what some good ways are to evaluate the quality of different preamps and converters. To an untrained ear, are there certain "challenges" you can subject them to that will highlight the differences and shortcomings?

Aside from just listening to a mix that youre very familiar with, Im wondering what a good way to tell is. I dont have much experience with a lot of different products so these differences arent obvious to me yet. I dont know what to listen for or how to make weaker components fall on their face.

maybe you should check these out


http://www.3daudioinc.com/home.html

these cds will let you compare stuff youll never afford.

they have a cd that compares mics another cd that comared mic pres and another
for converters.
so itll give an idea of the differences. of course.. other things come to play for this stuff. like which pres for which mic, monitors, room, cables bla bla etc.
but youll get a grip on why a telefunken is soooo expewnsive and not becuase others say so.

hope that helps.
those cds are not that expensive and will help a lot
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