Lavry Engineering Paper on Hi-Res

[bdiament]

Hi Peter,

 

**"...AFAIK, recordings benefit from a higher sample-rate and bit-depth because of the editing that takes place afterwards...."**

 

In my experience, there is always a benefit to longer word length when digital processing (not necessarily editing) is going to occur.

 

The reasons are numerous but among them is the fact that even the slightest process (say a gain adjustment of 1/4 dB) is going to lengthen the digital word. The word length of the processed file must exceed the word length of the target or low level information will be lost. This is one reason why mastering at 24-bits, even for a 16-bit CD target will result in a better CD. (Much of the software I use for mastering uses 48, 64 or 80-bit data paths.) With many processes, there is also benefit to high sample rates.

 

However, all that said, in my view, the main reason recordings benefit from higher sample rate and word length has to do not with any benefits for subsequent processing but simply with how they sound on playback, even when no processing is involved.

 

Different folks will hear different things of course and different gear will reproduce it differently. And different designers are going to have different ideas. As an engineer, what gets me is that with the better high res gear (I'm talking about 4x rates like 176.4 and 192k), for the very first time in my decades of recording, I'm getting back the sound of my mic feed. I never got this before from any analog or digital recorder, regardless of format or price. Even the best digital gear doesn't get close at 2x rates (88.2 and 96k), which I find closer to CD standard than they are to properly done 4x. But at 24/192 (my preferred rate), the sound coming back is the same as the sound going in. I never thought I'd hear it and at one time I would have bet that if I did, it wasn't going to be from a digital device.

 

To be clear, there is a lot of gear that sounds "very good". But if I'm seeking a non-editorialized capture of the input, "very good" is ultimately very bad. I want gear without a sound, rather than a "good" sound. (This is my personal preference. I understand some folks like certain colors and would not argue with what brings a person listening pleasure.)

 

My only regret in this regard is that so very much of the "192" spec'd gear out there seems to fall far short of the potential for the medium. As I've said elsewhere, I attribute this to clocking that is not up to the task and analog stages that aren't performing at these bandwidths. Unfortunately, as long as the opportunity for commerce exists, there will be folks planting the number 192 on devices that are already huffing and puffing at 96. (This doesn't say much for some of the devices that tout even higher numbers.)

 

Brings back the words of the poet, Paul Haines:

"Better a lot

of what's wrong,

than a little

of what's right."

 

As always, just my perspective.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

 

[bdiament]

Hi Jud,

 

**"...What would you say are the main ways in which 2x rates through good equipment fall short of your mic feed?..."**

 

I don't believe I've posted elsewhere about this.

Strange how I've been pondering how to answer your question since I first read it last night. If you were in my studio (or at a recording session), I could demonstrate the differences in seconds but articulating them in words is not so easy.

 

As a preface, I'll say that for my ears, the 2x rates show just how drearily lacking the 1x rates are. At least a cello sounds like a cello at the 2x rates. While it might be recognizable as such at 1x rates, a direct comparison will show the 1x more than a little bit reminiscent of a kazoo (this impression, which I have mentioned elsewhere, dates back to when I first heard 2x rates).

 

But the cello in the mic feed (and well done 4x) is still different. Even with the best 2x I've heard, there is a diminution of harmonic complexity. Nowhere near as drastic as with 1x but it still won't be confused with the mic signal (or the event itself).

 

Spatial cues too are just a bit "misty" and vague when compared with what comes from the mics. Not necessarily positioning but the space between and around the players sounds to me, like just a bit of focus has been lost. While much truer than 1x, I find there is still some difficulty in determining the size and materials of the space in which the event is taking place - something that is instant and obvious with the mic feed (and the best 4x).

 

Lastly, though not at all least, the bottom end sounds "very good", which is exactly what I find wrong with it. It is pleasing, extended, dynamic, etc. But it doesn't sound the same as what comes from the mics.

 

It is in these areas, particularly the bottom, that I find properly done 4x (much more rare than one might expect) to cross a threshold. Tonality and space sound like what I hear from the mic feed (again, this is something I've wished to hear for decades) and perhaps most amazingly to me, the bottom, for the first time in my experience, sounds like bass does in real life, with a speed and definition of pitch I've not experienced from any recording device before now.

 

I find the best 4x to offer so many sonic advantages; once that threshold is crossed, it really is magical. Hence, it always strikes me as odd when folks say 2x (or 1x !) is enough. It may be enough for them and that's fine. They may see 4x as overkill and that's fine too, though I admit to reading such statements as I would read one that insisted there are no colors in a rainbow. As long as I'm free to record at and to listen at 4x.

 

To be clear, this is just my perspective, how I hear it.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

 

[bdiament]

Hi Peter,

 

With apologies to our fellow CA members, a short answer here. In order to keep this thread on topic, we can continue off line (use the "Contact" page at one of the sites in my signature).

 

**"...I always record without any limiter or compressor, and during rehearsals I set the recording level to about -18 dB. My limited experience is that the actual performance is always louder...."**

 

I'm not sure what you mean by "-18 dB". Is that max peak level?

Are you recording at 24-bits? (If so, are you sure your hardware and software are able to? Regardless of what their spec sheets say?)

 

I always leave lots of headroom when recording and yes, the real performance always seems to hit higher peaks than the rehearsal. In my experience, A-D converters perform at their lowest distortion when the maximum peak is no higher than -6 dBFS. (In the old days - and still today for a few who don't realize it - folks thought they should see 0 dBFS max peaks for the highest resolution.)

 

As long as the format is truly 24-bit (hardware and software), I'd rather have a max peak at -20 than have it at -2. I find the end result is cleaner.

 

 

**"...After recording I usually need (?) to apply a steep high-pass filter @ 25 Hz. to reduce rumble from passing heavy traffic, air conditioners kicking in etc. Then, depending on recording-location I do some equalizing, but not much...."**

 

I know too many folks who believe applying a high-pass filter "cleans up" their recordings. Among the many (to me mistaken) assumptions, is that this will not affect the music. But in every single case I've heard over the years, the music ends up being thinned down.

 

What I've found is that all instruments, even an orchestral triangle, need that bottom. There must be a low end component to all of them because when you take it away and they no longer sound natural.

This, aside from the time smear that filtering will engender on top of the thinning.

 

**"...Last, I maximize the tracks to -3dB. and downsample to 16/44.1...."**

 

Questions I would as are:

Why -3dB? What are you using to effect the gain change?

What downsampler? Which dither algorithm?

 

Hope this helps - or at least provides some food for audio thought.

But out of respect for this thread, let us take this offline.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

[bdiament]

Hi Talk2Me,

 

**"...I read your very interesting and informative threat where you where trying to get higher res fro a blu ray player, and did you find a better sounding player (please no Oppo). Sorry for the OT people..."**

 

I sure hope that's a typo. I would hope I never posted (or uttered) a "threat" to anyone.

 

It wasn't simply the players that turned me off to Blu-ray for audio, it was HDMI.

 

I want to be able to get the 24/192 audio directly to the DAC of my choice and not the one built into the player or into any A/V receiver.

 

I know some folks have spoken of third-party interface boxes that may strip the audio from HDMI but my feeling is this is not how most folks would get to hear the music. (Besides, in my view, S/PDIF isn't exactly state of the art either.)

 

In any event, our own testing tells us that listening to the program material as .aif or .wav files from a computer (particularly using Firewire as the interface protocol to the DAC, rather than S/PDIF) gets the listener much closer to the original than any disc in any player or transport does, so I abandoned the idea of Blu-ray for our high res audio releases.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

 

[bdiament]

Hi Talk2Me,

 

I do use it for connection to the hard drive housing the music library - because I'm using Firewire for the connection to the DAC. ;-}

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

[bdiament]

It has long been evident to me (and I've posted to this effect elsewhere) that asking three audio people a question will tend to result in at least four different answers. With this in mind, my two cents:

 

While I find theoretical analyses of great interest, before reaching any practical conclusions based on these, I ask myself if I believe the analyses take every possible variable into account.

 

In the case of products whose only purpose in the Universe (of which I'm aware) is to be listened to, I've found actual listening to often be quite a bit more informative than anything else, more often than not, revealing what the theoretical analyses omit (or sometimes, outright deny).

 

My job involves listening to musical performances and making decisions about how hardware/software (and my engineering practice) reflect what I hear in the performance itself, before any hardware/software enters into the picture. Since I seek results as close as possible to being present at the event itself, I listen to what changes between what I hear from the position of the mic array to the sound of the mic feed, to what I hear when listening to a playback.

 

So, theory notwithstanding, I'll say what I've said before, which is with the best 4x digital, for the very first time in my decades of recording, I cannot as yet distinguish between the mic feed and the playback. With the very best 2x in my experience, it sounds "very good" but, as I delineated in an earlier post in this thread, not at all the same as the mic feed.

 

Let me put this another way: I've used all sorts of Sculley, Ampex, MCI, Studer and other analog recorders. I've used all sorts of digital recorders and a wide variety of A-D converters and D-A converters. They have, to my ears, all colored the microphone signals, except the best A-D/D-A converters running at 4x rates (i.e. 176.4 and 192k).

 

I remember the promise of digital and "Perfect Sound Forever" when I first encountered it in early 1983. To put it mildly, it was quite far from perfect. But, I figured, we've had analog for a hundred years and I saw no reason why digital wouldn't improve, given another hundred years. To my great delight, small improvements came only a few years later but the real improvement, the delivery on the promise took a bit over two decades; 80 years "early"! ;-}

 

I've finally (finally!) got gear that gives me back the sound of my mic feed. Nothing I've heard will do this at 96k but it will at 192k.

 

So what am I to make of a theoretical analysis that tells me this is inferior? Should I go back to 96k, which sounds "very good" but ultimately nothing at all like what the mics are sending, simply because of what a "white paper" says? I don't think so.

 

I think I'll continue working at the "inferior" (;-}) 192k and "suffer" a signal I can't distinguish from the mic feed.

 

As always, just my perspective

(perhaps theoretically "wrong" and if so, quite happily).

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

 

[bdiament]

Hi Rudi,

 

**"...I have my doubts however that they are singularly caused by going from a lower bit rate / bit depth to 192/24. The recording / reproduction chain's performance is the end result of the interaction of a long chain of components. Microphones, recording equipment, mastering, player, amp, speakers or headphones, cables, ears, brain, all contribute..."**

 

I can't speak for Keith but I can speak for myself.

 

Of course the recording (and reproducing) chain plays a big part.

Of course the recording itself makes the largest difference. I've said elsewhere that a high quality recording is identifiable as such, even after being converted to an eMPty3 and played in the car... on the highway, with the windows open!

 

I've also said my experience has been that 90-95% of the ultimate sound quality of any recording has already been determined by the time the signal is leaving the microphones - long before any other gear, analog or digital, high res or low, comes into the equation.

 

I'd rather have an mp3 of a great recording than the original master of a bad recording. This thread, however is about specific characteristic (sample rate and to a lesser degree, word length). For the purpose of my posts, I assume the signal being fed to the digital system, regardless of sample rate or word length is of high quality and the recording itself is not the concern here. Instead, the issue is how well that recording (or any other) will be represented at different sample rates and word lengths.

 

**"...As others have pointed out, it is extremely difficult to construct a test setup that ONLY tests the difference between 192/24 and 44/16 and nothing else..."**

 

I would disagree with this. Having used a wide variety of recorders, A-D converters, D-A converters and software over several years, to make a wide variety of recordings, a pattern emerges quite clearly. There are variations in any link in the chain the each has its "bests".

 

Though I can't speak for him, I think it safe to assume Keith J has also experienced a good variety of situations and has also found a clear, unambiguous pattern has emerged.

 

For me, even the best 16/44 is what I call "the cassette of digital audio".

I've already said I find 24/96 to sound "very good" but never close to being indistinguishable from the mic feed.

I've also said I find the jump from 24/96 to 24/192 be more significant than the jump from 16/44 to 24/96.

 

Lastly, I've reported on my experience that all too many converters claiming 192 in their specs actually perform *worse* at this rate than they do at 2x rates. I believe many mistakenly blame the format when in fact, the gear has not achieved anything like the format's potential.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

 

 

[bdiament]

Thanks for listening to the Soundkeeper recordings.

 

I'm glad you like the Led Zeppelin and Bob Marley CDs I mastered. Thank you for your kind feedback.

 

However, I would not consider the LZs exemplars of the highest fidelity - and this goes back, not to the format but to the signals leaving the microphones.

I am very pleased with the Bob Marley CDs and there are many memories I keep from those mastering sessions.

 

But none of this, in my view, has much to do with 16/44 vs. 24/192.

If you prefer Zeppelin and Marley to the artists on the Soundkeeper Recordings, that is fine. I would never argue with what brings another listening pleasure.

 

If it is the sonics you are referring to, I still would not argue with what brings another listening pleasure. But I would not compare the two in terms of fidelity to what occurred in the presence of the microphones.

 

Besides, you have both the 24/192 and 16/44 versions of the Soundkeeper Recordings. Perhaps you just prefer the sound of the 16/44 versions. Here again, I would not argue if that is the version you enjoy more on your system.

 

Having been at the recording sessions however, I would differentiate between preference and which sounds like the signals coming from the microphones.

 

Though my own personal bias is to preserve the unaltered sound of my microphones to the extent that is possible, I've come to understand that despite the lip service given to "high fidelity", not everyone wants (or likes) a sound with less coloration. Nothing wrong with this, of course, as the only purpose of our systems is to bring us pleasure.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

[bdiament]

Hi MJM,

 

**"...The microphone and mixing is beyond the control of the playback system, yet it is by far the most important factor..."**

 

No argument it is the recording itself that is the key.

However, the delivery format will determine just how much of that recording the listener gets to hear.

 

So while 24/192 in and of itself has no value without a good recording to deliver that way, the flip side (in my view) is, if you want to hear everything that recording has to offer, 24/192 (with gear that is truly up to the task and not merely marketed as being so) will do it in a way lesser formats cannot.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

[bdiament]

Hi Talk2Me,

 

**"...I think, all things considered, the sample rate (in itself), does not a great recording make..."**

 

I would agree 100%. There are plenty of bad recordings offered in high res.

 

However, if one has a good recording, the delivery format will largely determine just how much of that goodness the listener gets to hear.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

[bdiament]

HI Talk2Me,

 

Of course one can enjoy great music on a table radio too.

And some listeners will feel they are not missing anything by listening that way.

 

It depends on what one seeks in their listening.

I just happen to enjoy it a lot when the playback sounds like the mic feed itself.

Though I can enjoy the music even if I was listening to it over a telephone, to me, it isn't the same thing.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com