ack's system - end of round 1

853guy

Active Member
Aug 14, 2013
1,161
10
38
This is my new CD reference for extraordinary rendering of cymbals with relentless liveliness and energy, percussion, piano, tenor sax; Chesky JD51

Hi Ack,

I totally understand we all have different perspectives on what constitutes our musical preferences, and although there’s nothing to disagree with here since all we’re really doing is sharing those preferences, as someone who’s played drums for three decades I’d encourage you to have a quick listen to this:


Obviously, recording anything live is a challenge, and you’ve got to make creative decisions relative to the acoustics of the room, the players and in some cases, the music itself. To me, the Brian Blade clip is much more representative of relentless liveliness and energy (and much more representative of what cymbals in the context of a full drum kit sounds like), in addition to being much more harmonically complex and reproduced with much greater presence.

Again, this isn’t so much a right/wrong thing (and I’m not looking to start an argument - heaven forbid), just that I’m very curious as to your choice of album given your long-standing (p)reference re: “live unamplified music”. Perhaps if you have a listen to the Brian Blade clip and can help me understand your perspective, that would be much appreciated.

Cheers, Ack.

853guy
 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
This was a great piece, thanks! Is there a CD? I would like to hear it in the system because I can't say anything about the cymbal sound with the computer speakers; it's not possible; it certainly has the potential to be one of the best. But as you said, there is no right or wrong; identifying such references is partly based on being aware of the existence of great recordings, and thankfully, there are an incredible number of sensational recordings.

Here's another one I just played right now, first time in many years, and I think it stands to be one the greatest organ recording I have, along those from Reference Recordings. Part of it is the sense of space captured, which gives a sense of monstrous cavernous venue.

 

SCAudiophile

Well-Known Member
Sep 11, 2010
1,156
435
1,205
Greer South Carolina (USA)
This was a great piece, thanks! Is there a CD? I would like to hear it in the system because I can't say anything about the cymbal sound with the computer speakers; it's not possible; it certainly has the potential to be one of the best. But as you said, there is no right or wrong; identifying such references is partly based on being aware of the existence of great recordings, and thankfully, there are an incredible number of sensational recordings.

Here's another one I just played right now, first time in many years, and I think it stands to be one the greatest organ recording I have, along those from Reference Recordings. Part of it is the sense of space captured, which gives a sense of monstrous cavernous venue.


ack,

You are spot-on there....this is an all-time GREAT organ performance and recordings. I also like many on Hyperion, AEOLUS, DG Gold and JAV Recordings. Some of my all-time favorites are Daniel Roth's and other performances at Saint Sulpice in Paris and the various other Cavaille-Coll instruments in France at the big cathedrals. What amazing instruments and performances. Fantastic recordings too...happy to share lists of favs via PM or here/a new pipe organ thread...
 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
Hi there,

Feel free to post anywhere you want; organ gets my juices flowing!
 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
And since this is becoming sort of a Craig Dory/Dorian appreciation day - who used FM Acoustics to monitor his recordings - here are some relevant links

Part of his catalog http://www.sonoluminus.com/c-6-dorian-recordings.aspx?pagenum=5
His resume http://cats.rpi.edu/node/157
On FM Acoustics and the St. Eustache recordings https://www.fmacoustics.com/testimonials/reference-letters/

As well, the "window" through which we look into the recording seems to be "cleaner" with the FM 811 and FORCELINES cables. In addition, one of the more impressive features of the FM 811/FORCELINES combination is their ability to control loudspeakers in the low end of the audio spectrum where time-coherent current delivery and speaker control are most critical. Our organ recordings with Jean Guillou and our orchestral recordings with the Dallas Symphony are particularly challenging to amplifiers and their ability to control woofers. The FM ACOUSTICS amp and cables produce a seemingly bottomless and distortion-free low-end, with absolute control of the loudspeaker.

We have never heard another amplifier reproduce the 16-and 32-foot stops from the Tonehalle and St. Eustache organs properly. Until we began using the FM ACOUSTICS amps and FORCELINES, we had no idea, for sure, whether or not certain passages with complex organ pedalwork had actually made it onto the recording or not. Because of the current demands placed on the amplifier by our recordings, those passages always sounded muddy and somewhat bloated. After listening with the FM 811 and FORCELINES cables, we were definitely relieved to hear that all the music from Jean Guillou's performances had made it to the recordings. WOW!

BTW, I have said time and time again that FM Acoustics - like Spectral - require their own cables (Forcelines), simply because the electronic ingress and egress of the amplifiers are at the tips of the cables.
 

853guy

Active Member
Aug 14, 2013
1,161
10
38
This was a great piece, thanks! Is there a CD? I would like to hear it in the system because I can't say anything about the cymbal sound with the computer speakers; it's not possible; it certainly has the potential to be one of the best. But as you said, there is no right or wrong; identifying such references is partly based on being aware of the existence of great recordings, and thankfully, there are an incredible number of sensational recordings.

Hey Ack,

No CD unfortunately. It was a master class put on by the Chicago Music Exchange and recorded live in the store. “Landmarks” is available on the album of the same name (Blue Note, 2014), and “Stoner Hill” from Season of Changes (Verve, 2008). “King’s Highway” is a cover of Joe Henry’s taken from Short Man’s Room (Mammoth, 1992).

I did consider perhaps your system wasn’t set up for streaming. And I didn’t so much post it to be the definitive representation of any sort of “best”, just that I personally consider it more representative of what live sounds like than not relative in particular to the overtones and harmonics of a drum kit. As you say, there are some truly exceptional recordings available - I simply posted the YouTube link because, aside from loving Brian as a musician and leader, it would be available for anyone to listen to if they wished.

And yes, preference is really all we have. Identifying them apropos live music and recordings is part of the process for developing/evolving them. A drum kit is an interesting instrument to record, and every engineer will of course bring their own set of preferences.

Best,

853guy
 

FrantzM

Member Sponsor & WBF Founding Member
Apr 20, 2010
6,455
29
405
Hi Ack,

I totally understand we all have different perspectives on what constitutes our musical preferences, and although there’s nothing to disagree with here since all we’re really doing is sharing those preferences, as someone who’s played drums for three decades I’d encourage you to have a quick listen to this:


Obviously, recording anything live is a challenge, and you’ve got to make creative decisions relative to the acoustics of the room, the players and in some cases, the music itself. To me, the Brian Blade clip is much more representative of relentless liveliness and energy (and much more representative of what cymbals in the context of a full drum kit sounds like), in addition to being much more harmonically complex and reproduced with much greater presence.

Again, this isn’t so much a right/wrong thing (and I’m not looking to start an argument - heaven forbid), just that I’m very curious as to your choice of album given your long-standing (p)reference re: “live unamplified music”. Perhaps if you have a listen to the Brian Blade clip and can help me understand your perspective, that would be much appreciated.

Cheers, Ack.

853guy

Listening to this youtube Video , I looked for the CD and did not find it so I re-visited the Youtube clip... I must say that I found the youtube video quite enjoyable .. :( :b (descent toward the abyss , i am becoming less and less exigeant :() .. When the recording and mastering are excellent the format ( to a point) doesn't seem to matter ...

I didn't know about him, discovered him through this thread.. Very interesting musician. Many of is albums are on Tidal and Spotify ...A week of new Music discovery

I haven't looked them all but some of the albums on Ack's playlist are on Tidal .... You can't stop the inexorable march of Progress :)

For the Tidal fans ,
 

853guy

Active Member
Aug 14, 2013
1,161
10
38
Listening to this youtube Video , I looked for the CD and did not find it so I re-visited the Youtube clip... I must say that I found the youtube video quite enjoyable .. :( :b (descent toward the abyss , i am becoming less and less exigeant :() .. When the recording and mastering are excellent the format ( to a point) doesn't seem to matter ...

I didn't know about him, discovered him through this thread.. Very interesting musician. Many of is albums are on Tidal and Spotify ...A week of new Music discovery

I haven't looked them all but some of the albums on Ack's playlist are on Tidal .... You can't stop the inexorable march of Progress :)

For the Tidal fans ,

Hi Frantz,

Yes, like I mention above to Ack it was a live in-store performance, but a beautiful one for sure.

I first discovered him when he played on Joshua Redman’s Spirit of the Moment: Live at the Village Vanguard, Brad Mehldau’s Introducing, Kenny Garrett’s Triology and Emmylou Harris’ Wrecking Ball all in the same year. Pretty auspicious start.

Since then he’s forged a career of incredibly soulful and nuanced playing, and developed into a great band leader, composer and a not-too bad singer/songwriter (Mama Rosa (2009)), though excels at the former.

It’s hard to recommend anything specific, as he’s been quite eclectic in his output - everything and everyone from Joni Mitchell to Steve Earle, Norah Jones to Daniel Lanois, Bill Frisell to Wayne Shorter, Wolfgang Muthspiel to Bob Dylan. If you had to start somewhere, I’d look to his Brian Blade Fellowship stuff for the kind of gospel-tinged and Americana-influenced modern jazz that moves me more than most.

Have fun.

853guy

P.S. Before I pull Ack’s thread too much more off-topic, one of the things I love about Brian’s playing is that you can hear Tony Williams, Art Blakey and Elvin Jones in there (for me, the holy trinity), and even though he’s fully embraced and owned his influences, he’s moved past them to develop his own voice. That is, he understands both the form and the content of the art form known as ‘jazz’, but has pushed it into directions that have taken on and reacted to influences outside it. It’s one of the things that for me, differentiate a ‘musician’ from a ‘drummer’.

In short, it’s everything that’s wrong with Whiplash. But I digress.
 
Last edited:

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
More on this Alpha DAC

I had the Spectral SDR-4000SV recently on loan, and by using the same interconnects but a lesser SPDI/F digital cable to the Alpha from the 4000SV (because I only have an AES/EBU MIT), the impression was that this Alpha matched the 4000SV in all aspects, and slightly surpassed it in bass extension and articulation.
 
Last edited:

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
Pushing the envelope even further

A couple of recent changes with the sources:

1) I was finally able to locate one of the rare Spectral SDR-3000SL transports a little while ago. This one appears to be in top shape. It pushes the DAC an extra ~5% by dropping noise and jitter even further. Sonics stride into new territory, with more vividness, attack, dynamics and ... ahem... perhaps for the first time, a lot of you-are-there transparency. I never thought 'transparency' would ever be an RBCD attribute, and HDCD pushes it even further. This is yet again testament to how critical noise and jitter are in all things digital. Despite the success of my DAC mods, I would not be able to get these results without a fundamentally sound original design in the processor - so kudos to the Berkeley team. This is now truly analog sound - quite impressive, IMO.

2) Speaking of analog, with the digital upgrades having left my analog far behind, I was scratching my head as to why I was unable to get the same level (or any level) of transparency out of the XP-25 phono, which others claim they do. As it turns out, running a balanced connection from the XP-25 to the 30SV preamp was a mistake: I decided to compare the RCA vs the XLR out of the phono, and to my surprise, it turns out the preamp attenuates the XLR-in by -3dB compared to RCA-in - totally unexpected... To verify, I measured the phono's output, and with a 1kHz tone, RCA-out measures 0.27V, and XLR-out 0.27V (ground to pin2 or pin3) & 0.54V (pin2 to pin3), as expected; so the phono is doing the right thing. To make a long story short, the 30SV manual and bulletin claim the XLR-in is really for high-output DACs, so this was the wrong connection for phono. Therefore, I switched to the RCA connections and the sonic improvement is literally shocking: increased vividness, dynamics, tighter bass, attack, and ... ahem.. a lot of transparency. Live and learn... Last time, Al and I were commenting how much better the Janaki Trio's Debut sounded from digital, and I surmised the LP pressing might have been bad. Not anymore, they are virtually identical, though noise is still lower from the DAC.

Fun times

T5D_4143.JPG
 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
As I revisit every CD in my collection I can't help but re-iterate the increase in dynamic headroom with this 3000SL transport, along with everything else. On the Proteus 7 "For Your Ears Only", the dynamics are truly shocking and frightening; the increase in headroom must be no less than 3dB, which is huge, with additional low-bottom drive, control and definition. At the same time, I have never heard such smooth and metallic cymbals anywhere else yet - truly fascinating what properly implemented Redbook can do; and this is not even HDCD. Craig Dory was decades ahead of his time with the Dorian recordings - simply jaw dropping, period. The Spectral SDR-4000SV came fairly close to this level of sound, but not close enough.

Loosely comparing from memory where the system stood in terms of dynamic expression and headroom five years ago as compared to today - with older generation electronics all around back then but same modified ML speakers - it won't be an exaggeration to say there is a 10-15dB increase; it is truly fascinating.
 

Al M.

VIP/Donor
Sep 10, 2013
8,696
4,489
963
Greater Boston
Fascinating, Tasos. Can't wait to hear your system again. The dynamics on the Proteus 7 "For Your Ears Only" had already been great, curious to experience further improvement.
 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
MIT speaker cables, SD vs HD - again

After having finally brought my analog and digital to a level I feel comfortable to say there is great transparency and immediacy, I revisited the SD vs HD issue in the MIT speaker cables once again.

On page 24 I wrote:

MIT speaker cables, SD vs HD
: I wrote a while ago in these pages that SD is it for me. Apparently, as it now turns out, HD was simply exposing and accentuating sonic deficiencies upstream, and once these are cleared, the HD setting with these extra F.A.T poles works just fine and also as advertised: life-like transients. Moreover, the treble cleanliness (especially the metalic cymbal character) & treble dynamics that you heard are directly attributed to it, and not properly corrected by the SD network - I should have demonstrated this, it is quite easy to tell. Treble dynamics are particularly hard to render correctly by any component.

I have now done numerous A/B tests, and undoubtedly what I said above holds subjectively entirely true: in the right system, HD can provide life-like transients, and clean and dynamic treble. And now, to that list, add transparency and additional dynamic headroom. Switching to SD drops transparency quite significantly in the entire spectrum, and perceived dynamic headroom also suffers. I would call it 'polite'.

I would now go as far as to say that the MIT 90.1 would be the lowest grade speaker cable I would use for the 30SV/400RS, and I am glad I went for it years ago; and if the system can "handle" the HD setting, absolutely go for it. But to get to "HD", the entire system apparently has to be extremely linear, very transparent and exceptionally low in noise. I just can't go back to SD at this point.
 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
Noise is such a killjoy

Well, nothing new here for just about everyone, but I wanted to quantify it yet again, this time with praise for the MIT Magnum Z Trap http://www.mitcables.com/available-in-stores/magnum-z-trap.html (says no longer available, but they can make it). I have both speakers, sub, the transport and the DAC plugged into the same Z-Strip, and the Trap now sits between the wall and the Strip. I can now easily hear the same extremely low level detail out of the panels as I do from my headphones, and the bass is more articulate... so much so that on the Mahler 2nd's opening, at the point midway where the bass drum is played solo extremely softly, the body of the instrument is all there albeit very low in volume. It's been killing me to get this right for years, and the system has gone from rendering no sound during that 10-second part many years ago, to doing it right... finally.

We all approach noise control in many different ways, but there are clear and measurable benefits to doing it "right" - however you define that. Again, nothing new to anyone, just another data point.
 
Last edited:

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
Four important additions to the music library

The Flamenco LP re-issue with Direct Metal Mastering outclasses the CD I've had for decades - and discussed in these pages - and by a wide mile in terms of presence and clarity; however, the presence region is tipped up, and therefore, is timbrally wrong - quite evident with the male vocals.

The Fone are simply outstanding, and claim "One-Stage Processing" perhaps like Mofi's recent one-steps?!??? Mr. Ricci knows exactly what he's doing and they are true reference recordings; the mics are apparently standing on the wooden platform, which occasionally generates footfall rumble. The last I Musici LP is the first Fone I bought years ago, and is probably the best of them all, and one of the very few 200g he's put out. I also think I have a personal bias towards the Neumann mics he's using

 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
On the HDCD patent

In the recent MQA discussion, I brought up HDCD again and how more natural it sounds than typical redbook - the patent is at https://www.google.com/patents/US5872531. Since I keep having to re-read the brief on it that I wrote up on the MLO forum back in 2010, I thought it's time I copied and edited it over here as well.

The following are some of the more important claims made in the patent, with most parts copied verbatim to preserve fidelity, and hopefully I have not misrepresented anything - but the more techno savvy should feel free to make necessary corrections... For me, the most important ones are those in Notes 3 & 4, and especially the bit about over-20kHz human perception ability (about which I have written in the past http://www.whatsbestforum.com/showt...r-Cells-responding-to-frequencies-up-to-79kHz; Roger Skoff also discussed the effects of the "inaudible" Sopranino ultrasonic supertweeter in conjunction with the Haas Precedence Effect in the January 2017 TAS essay, where the leading edge of ultrasonic frequencies help focus the ear to the location of the sound source, thus enhancing the perceived realism):

Basic claim: compatible system which provides an adaptive interplay of gain, slew rate, filter action and wave synthesis processes to substantially reduce signal distortions and improve apparent resolution. Resolution is selectively and adaptively traded off for slew accuracy, and slew rate or maximum level is borrowed for higher resolution. Information rate is conserved by toggling back and forth or fading from process to process when needed.

Specific claims include:

1) Most digital distortions can be predicted, as they are strongly related to signal conditions which are easy to identify. For a given signal, one can choose a best encode-decode process having the least audible or sonically damaging distortion. If one must operate with the Nyquist limit, then a transient response versus alias compromise exists. HDCD is a series of techniques to address various kinds of distortion. Such techniques include: fast peak expansion, averaged low level gain reductions, selecting complementary interpolation filters, waveform synthesis, record-compress/play-expand system (with some features similar in ways to those used in noise reduction systems, but unlike those, it corrects distortion), and others. See Note 6.

2) Uses the least significant bit of a word for encoding the command codes and other auxiliary data, thus adds the slightest amount of noise (other techniques are also discussed but not utilized because they would presumably break compatibility with non-HDCD processors). However, to make it inaudible, it is encoded or encrypted to a random number sequence which is inserted on an as-needed basis in a serial fashion, one bit per word [external literature claims that the HDCD encoding accounts for 3-4% of the entire dataset]. See also Notes 1 and 2 for more details. In typical classical music programming, the control signal would be inserted for intervals of about a millisecond each occurring several times per second at most. The loss of full program resolution for these brief intervals is not noticeable.

3) Thus, lack of HDCD decoding yields a signal with slightly less dynamic range and only slightly higher background noise. However, the signal will have lower quantization and slew induced distortions and, hence, the processed encoded product, when reproduced on non-decoding standard equipment, will sound equal to or better than an unencoded product.

4) The signal is delayed during encoding, and by using look-ahead and look-behind techniques, an optimal encoding technique is identified - and only one is active at any given point in time - to address the issue. This is done in order to address digital distortions which occur at extremes of high level, slew rate, and high frequencies, on one hand, and with quiet signals and short small transients on the other hand; the best encode/decode strategy is chosen for that extreme without the process compromise hurting the opposite aspects of the program.

5) The decoder has a much easier job, because the complementary decoding technique is already defined during the encoding. On the other hand, the encoder would be best served if implemented with higher sample rate and wider word length. Computing power matters here. There is nothing in the patent that prevents the decoder from doing further analysis and adjustments on playback; this may partly explain why recent HDCD playback systems sound better than previous generations with the same old HDCD recordings (PMD-100 vs PMD-200 vs custom processor-based solutions).

6) Reproduction of higher-than-Nyquist-limit frequencies is possible without creating sub-harmonic or foldover distortions[!!!]. Does this mean that DACs/players that implement brick wall filters in the digital domain using SHARC processors (like the Spectral SDR-4000 series and the Berkeley Alhpha DAC) take advantage of this by cutting off in software, thus avoiding anti-aliasing-filter phase issues, even better than so-called 'apodizing' filters? See Notes 3 and 4.

7) Minute details, like hall reverberation mixed in otherwise loud bass sounds, are usually attenuated or lost in conventional red book encoding, producing a collapse of the sense of space in a recording, but preserved by the invention. Such distortions occur when very small signal amplitude changes of about 5 to 20 millivolts are mixed with a larger low frequency dominated signal and are, thus, averaged at many different voltage levels of a larger slow waveform.

8) The decoded signal may have an apparent increase of bandwidth and resolution External literature claims 18-20 bits; the patent claims 'The system modifies signals to achieve 18 bit performance from a standard 16 bit converter system', and 'the dynamic range for fully decoded reproduction in accordance with the invention has increased almost 20 dB. Average resolution is substantially more than 18 bits', and 'The result of decimation [during D/A] is a signal having approximately 20 bit resolution at one-times sampling rate... this signal is then packed into 16 bit words and adds control information for use by the reproducer'.

9) Following the invention, one process can borrow information rate from a less needed performance capability when potentially severe distortion conditions in the signal call for it. In this manner, a decision to provide more points per fast voltage change yields an equivalent higher sampling rate at the expense of less important low level resolution. Conversely, a smaller voltage change per sample automatically reduces the momentarily unneeded speed capability. Such interplay and compromise can be managed and/or computed to maintain a substantially constant digital information rate.

10) A correction strategy is applied to reduce filter trade-off compromise errors between transient response, phase accuracy, settling time, group delay, and other distortions inherent with filtering methods. See Note 5.

11) On sample-time jitter and internal crosstalk: The system of the present invention stops all operations long enough before sampling to allow the energy stored on cables and other energy storage parts to dissipate (noise from cables, IC's and other parts becomes ten to one hundred times less and a signal sample to accurate to millionth's of a volt occurs). One pulse initiates sampling which then occurs during electrical silence. Once the analog signal is sampled and safely held, the conversion process resumes and the digital code is sent to the digital signal processors. In order to keep sample-time jitter to a minimum, we place the system clock in the A to D converter module.

The following are copied mostly verbatim:

NOTE 1: Sharing the LSB with the main program data means that the reproducer has to be able to identify the commands embedded within the stream of arbitrary main program data. This is accomplished by preceding a command code with a synchronizing sequence of bits which the decoder looks for in the data stream. False triggering of the reproducer on program data can be completely eliminated by having the encoder monitor the program data stream during recording and alter the least significant bit in one word if the synchronizing sequence is about to occur, thereby preventing it.

NOTE 2: The process control signal is hidden in the least significant bit of the digital audio channel by modulating it with a noise signal. The circuit consists of a pseudo-random noise generator based on a [31-bit] shift register with feedback which implements a maximal length sequence. This type of generator produces a deterministic sequence of bits which sounds very random, and yet is a reproducible sequence. The output of the noise generator is added to the control signal modulo-two (exclusive-or'ed), modulating the signal with noise, or scrambling it. The result is then inserted into the least significant bit of the record serial data stream. On the play side, the least significant bit is extracted from the serial digital stream and the output of a matching shift register is subtracted from it, modulo-two (exclusive-or again). The result is the process control signal, unscrambled again.

NOTE 3: An important advantage is that the "brick wall" low-pass filter required to prevent Nyquist--Alias errors can be implemented as a digital filter, which has highly reproducible characteristics free from phase distortions. The characteristics of this filter can be chosen dynamically based upon an analysis of the high resolution signal to minimize distortion. Hence major filter and analog to digital encode system problems such as pre-echo, transient ringing, group delay anomalies, missing code errors, alias distortion and beats are greatly reduced or eliminated.

NOTE 4: Recent research has shown, however, that humans use transient information in sounds with frequencies much higher than [Nyquist] to determine the direction from which the sound has come, and that eliminating those very high frequency components impairs one's ability to locate the source of the sound. The inner ear actually has nerve receptors for frequencies up to about 80 kiloHertz. Therefore, if the "brick wall" low-pass filter, which is a necessary part of all digital recording, removes frequencies above about 20 kiloHertz in transients, it reduces the level of realism in the sonic image.

NOTE 5: A transient to be reconstructed is identified at the encoder, and its wave shape is matched to one of a number of predetermined "standard" transient shapes, which are known to both the encoder and decoder. A command code identifying the shape is sent through the control channel to the decoder, which regenerates the shape, either by reading it out of a lookup table or algorithmically generating it [this is another place where a lot of computing horsepower would come into play], and scales it to the amplitude of the bandlimited transient arriving in the main signal.

NOTE 6:
  1. It uses ratios of high frequency content to total amplitude along with detected isolated transients to select filter programs for the decimation filter.
  2. It measures the average signal level of the broad middle frequency spectrum and uses the results to control the gain of the low level compressor. It also generates reproducer control codes to correctly complement the encode gain structure.
  3. It measures the average level of low level high frequency signals, and invokes dynamic dither insertion of extra high frequencies when appropriate.
  4. It analyzes the distribution of peak amplitudes to determine if the incoming signal has been limited prior to the encoder. If so, it can raise the threshold of the encoder's soft limit function, or turn it off altogether.
  5. It can compare the decimated signal to the oversampled one delayed to match the decimation to look for isolated bursts of high frequency information which represent transients which would not fit within the normal 22 kiloHertz bandwidth. These difference signals can be sent to the reproducer in the control channel, spread in time, so that the reproducer can correct the transient on playback.
  6. It can also use the transient analysis to control slew rate limiting of the main signal as an alternate approach to increasing the apparent bandwidth of the system.


PS: The detailed descriptions of the actual circuit designs are beyond my understanding, but appear phenomenally complex and equally fascinating.
 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
The "Hypersonic effect"

Continuing on the discussion on ultra high frequency perception, this is a brief introduction to a couple of controversial papers branded the "Hypersonic effect" (2000, 2006) - wikipedia describes the whole thing well https://en.wikipedia.org/wiki/Hypersonic_effect

The claims can be summarized as follows:

1) The subjects would respond to the High Frequency Components (HFC; above ~22-25kHz) only in the presence of Low Frequency Components, in a musical program; they would not respond to HFC w/o LFC
2) The eardrum may not be directly involved in HFC perception, and only with HFC exposure to the entire body did the subjects respond
3) They have allegedly measured "statistically significant" increase in brain activity with the presence of LFC+HFC than just LFC

Specifically from Wikipedia:

In research published in 2000 in the Journal of Neurophysiology, researchers described a series of objective and subjective experiments in which subjects were played music, sometimes containing high-frequency components (HFCs) above 25 kHz and sometimes not. The subjects could not consciously tell the difference, but when played music with the HFCs they showed differences measured in two ways:



  • EEG monitoring of their brain activity showed statistically significant enhancement in alpha-wave activity
  • The subjects preferred the music with the HFCs

No effect was detected on listeners in the study when only the ultrasonic (frequencies higher than 24 kHz) portion of the test material was played for test subjects; the demonstrated effect was only present when comparing full-bandwidth to bandwidth-limited material.


It is a common understanding in psychoacoustics that the ear cannot respond to sounds at such high frequency via an air-conduction pathway, so one question that this research raised was: does the hypersonic effect occur via the "ordinary" route of sound travelling through the air passage in the ear, or in some other way? A peer-reviewed study in 2006 seemed to confirm the second of these options, by testing the different effect of HFCs when presented via loudspeakers or via headphones — the hypersonic effect did not occur when the HFCs were presented via headphones[SUP].

[/SUP]
The 2006 study also investigated the comfortable listening level (CLL) of music with and without HFCs, an alternative way of measuring subject response to the sound. The CLL for the music with HFCs was higher than that for the music without HFCs - this provides a quantitative way to demonstrate general listener preference for the music with HFCs.

The same wikipedia article also describes natural skepticism:

Researches from NHK laboratory have attempted carefully but unsuccessfully to reproduce Oohashi's results.


480 man-hours of listening tests conducted at the London AES convention in 1980 by Laurie Finchman of KEF concluded that subjects could not distinguish a 20 kHz band limited version of a test signal from the original played back on equipment capable of reproducing sound up to 40 kHz.


System non-linearities (present to varying degrees in all audio reproduction electronics, loudspeakers, etc.) are known to produce lower-frequency intermodulation products when the system is stimulated with high frequency signals. It is suggested that this mechanism could produce signals in the audible range that allow listeners to distinguish the signals.[SUP][12][/SUP][SUP][16][/SUP] Artifacts like this are a common problem with PC-based hearing self-tests, for instance[SUP].
[/SUP]

In September 2007, two members of the Boston Audio Society and the Audio Engineering Society published their study in which about half of the 554 double-blind ABX test listening trials made by 60 respondents showed the correct identification of high-resolution or CD-standard sampling rate. The results were no better than flipping a coin, producing 274 correct identifications (49.5% success), and it would have required at least 301 correct identifications given 554 trials (a modest 54.3% success rate) to exceed a 95% statistical confidence of audible difference, which will happen about once in twenty such tests by chance alone
Nonetheless, here are the papers

1) "Inaudible High-Frequency Sounds Affect Brain Activity: Hypersonic Effect" - http://jn.physiology.org/content/83/6/3548


Abstract

Although it is generally accepted that humans cannot perceive sounds in the frequency range above 20 kHz, the question of whether the existence of such “inaudible” high-frequency components may affect the acoustic perception of audible sounds remains unanswered. In this study, we used noninvasive physiological measurements of brain responses to provide evidence that sounds containing high-frequency components (HFCs) above the audible range significantly affect the brain activity of listeners. We used the gamelan music of Bali, which is extremely rich in HFCs with a nonstationary structure, as a natural sound source, dividing it into two components: an audible low-frequency component (LFC) below 22 kHz and an HFC above 22 kHz. Brain electrical activity and regional cerebral blood flow (rCBF) were measured as markers of neuronal activity while subjects were exposed to sounds with various combinations of LFCs and HFCs. None of the subjects recognized the HFC as sound when it was presented alone. Nevertheless, the power spectra of the alpha frequency range of the spontaneous electroencephalogram (alpha-EEG) recorded from the occipital region increased with statistical significance when the subjects were exposed to sound containing both an HFC and an LFC, compared with an otherwise identical sound from which the HFC was removed (i.e., LFC alone). In contrast, compared with the baseline, no enhancement of alpha-EEG was evident when either an HFC or an LFC was presented separately. Positron emission tomography measurements revealed that, when an HFC and an LFC were presented together, the rCBF in the brain stem and the left thalamus increased significantly compared with a sound lacking the HFC above 22 kHz but that was otherwise identical. Simultaneous EEG measurements showed that the power of occipital alpha-EEGs correlated significantly with the rCBF in the left thalamus. Psychological evaluation indicated that the subjects felt the sound containing an HFC to be more pleasant than the same sound lacking an HFC. These results suggest the existence of a previously unrecognized response to complex sound containing particular types of high frequencies above the audible range. We term this phenomenon the “hypersonic effect.”




2) "The role of biological system other than auditory air-conduction in the emergence of the hypersonic effect." - https://www.ncbi.nlm.nih.gov/pubmed/16458271


Abstract

Although human beings cannot perceive elastic vibrations in the frequency range above 20 kHz, nonstationary sounds containing a wealth of inaudible high-frequency components (HFC) above the human audible range activate deep-lying brain structures, including the brainstem and thalamus and evoke various physiological, psychological, and behavioral responses. In the previous reports, we have called these phenomena collectively "the hypersonic effect." It remains unclear, however, if vibratory stimuli above the audible range are transduced and perceived solely via the conventional air-conducting auditory system or if other mechanisms also contribute to mediate transduction and perception. In the present study, we have examined the emergence of the hypersonic effect when inaudible HFC and audible low-frequency components (LFC) were presented selectively to the ears, the entrance of an air-conducting auditory system, or to the body surface including the head which might contain some unknown vibratory sensing mechanisms. We used two independent measurements based on differing principles; one physiological (alpha 2 frequency of spontaneous electroencephalogram [alpha-EEG]) and the other behavioral (the comfortable listening level [CLL]). Only when the listener's entire body surface was exposed to HFC, but not when HFC was presented exclusively to the air-conducting auditory system, did both the alpha-EEG and the CLL significantly increase compared to the presentation of LFC alone, that is to say, there was an evident emergence of the hypersonic effect. The present findings suggest that the conventional air-conducting auditory system alone does not bring about the hypersonic effect. We may need to consider the possible involvement of a biological system distinct from the conventional air-conducting auditory nervous system in sensing and transducing high-frequency elastic vibration above the human audible range.
 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
In defense of the Hypersonic Effect

Despite prior skepticism over the aforementioned Hypersonic Effect research (2000, 2006) in the past (the origins of which date back to 1991), here's a paper from 2014 which verifies that research using natural ocean waves - which are rich in HFC - artificially enhanced with additional HF content. The 50 subjects were 19 to 59 years old

"Inaudible High-Frequency Sound Affects Frontlobe Brain Activity" - http://www.m-hikari.com/ces/ces2014/ces21-24-2014/shimhanmoiCES21-24-2014.pdf

Abstract

High-frequency is sound produced in non-audible area, which couldn't be heard in daily life. The frequency range above 22 KHz is called 'high-frequency' and its components are called 'HFC (High-Frequency Components)'. It is known that ocean wave sound is rich in HFC, because it brings serenity and causes ?-waves in human mind. When this natural sound is combined with high-frequency, it seems to give a pleasurable feeling, indicated by a ?-wave increase and a ?-wave decrease. We call this phenomena "the hypersonic effects". In this experiment, subjects listened to the ocean wave sound simultaneously with corresponding frequencies similar to ocean wave frequency components created artificially in a electric circuit. Brain waves were measured by an EEG system with 8 channels using 2 electrodes on Fp1, Fp2. The results showed that ?-wave increase and ?-wave decrease were statistically significant while subjects were listening to ocean wave sound along with the high frequency components, reflecting the hypersonic effect.

...

Table.2 shows ANOVA analyses results between the experimental group (that heard the ocean wave sound and the high-frequency component simultaneously) and the control group (that heard the ocean wave sound only). All of the 2EEG channels were analyzed. The relative powers of Alpha and Beta brain waves At Fp1 and Fp2 were significantly different between the two groups(Fp1 < 0.01, Fp2 <0.01). This result was consistent with Tsutomu (2000)'s study results in which alpha waves were also increased at the occipital cortex
...
As shown in Table 3, Beta waves were also decreased significantly at Fp1 and Fp2 (Fp1<0.05, Fp2<0.01). Beta waves regarded as the signs of tension and arousal were decreased at the pre-frontal lobes when people heard the ocean wave sound and the high-frequency component at the same time.
...
In other words, when a ocean wave sound is heard with the high frequency component, the listener feels more pleasure, pleasantness, and feels less tension and more relaxed. Some researchers including Oohashi(1991,2002) and Tsutomu (2000,2006) investigated this phenomenon called 'the hyper sonic effect' but the exact causes of this phenomenon has not been clearly revealed.
...
The present study differed from the previous studies in that it did not need an expensive speaker or high frequency CD player and that it was very simple and useful to be applied in developing a device to have the hypersonic effect. However one of the weaknesses of the high frequency component is that it loses its power abruptly specially as the distance from the sound source increases so that it should be placed very close if it is to be effective.
 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
On the Spectral DMA-500s

While I continue reading up on the science of the ear, a parenthetic comment that I will be replacing the DMA-400s with the new DMA-500 Anniversary Reference. I will share detailed impressions soon, but suffice it to say the level of realism (with the right recordings) rendered by these amps is right up there with the best mega-OTLs I have heard and perhaps better, and quite frankly, arresting. The 400s are not far behind, so I continue enjoying the music at home, but I am looking forward to selling the farm for the 500s.

If I were to briefly describe these amps, I would say Raw with Molecular Resolution, which makes them completely transparent to the recording.

One other thing I have come to conclude is that the speakers I have built are overall superior to the Magico M3, having listened to them at least three times, so far.
 

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. This is THE place where audiophiles and audio companies discuss vintage, contemporary and new audio products, music servers, music streamers, computer audio, digital-to-analog converters, turntables, phono stages, cartridges, reel-to-reel tape machines, speakers, headphones and tube and solid-state amplification. Founded in 2010 What’s Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals, we enjoy learning about new things and meeting new people, and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing