- How does BACCH enhance the spatial realism in the reproduction of acoustical recordings made in real acoustical environments?
Crosstalk cancellation (XTC) techniques, such as BACCH, suppress the sound recorded on the left (right) channel of a stereo recording at the right (left) ear of the listener during stereo playback from a pair of loudspeakers. This cancellation raises the limit on the level of interaural level difference (ILD) and interaural time difference (ITD), above the levels that the speakers can deliver without XTC, allowing more of the correct spatial cues of the recorded sources to be reproduced at the ears of the listeners. (ILD is the difference between the sound pressure (in dB) caused by a given source at one ear minus the pressure at the other ear. The ITD is the difference between the sound arrival times at the two ears. Both are generally frequency-dependent functions.)
This is best illustrated by first considering the case of ILD (the case of ITD will be discussed subsequently) and acoustical stereo mic recordings in a real space.
Most, if not all, of the statements below can be verified by the experimentally-minded reader using the BACCH-BM microphone and the recording and extensive measurement capabilities of the BACCH-dSP application at the heart of Theoretica’s BACCH4Mac packages.
It is insightful to first consider the general case of a Binaural dummy-head recording, then it would become easier to understand the more particular case of regular stereo miking techniques. The latter are of two general types: Type A stereo miking techniques, that rely on ITD to code the stereo image (e.g. ORTF, XY, and other coincident mic techniques, etc..) and Type B stereo miking techniques that rely on the ILD to code the stereo image (e.g. spaced omni or A-B mics, Decca tree, Jecklin disk, etc…)
Binaural Recordings:
The general case of binaural dummy head recording is the most natural (i.e. most akin to how humans hear) as it captures both the ILD and ITD cues, as well as the so-called spectral cues (which are associated with the non-flat frequency response imposed by the diffraction of the sound waves around the torso, head, and pinnae of the dummy, or human, head wearing the in-ear microphones.) This individualized frequency response, which helps the brain-ear system locate sound sources according to the tonal coloration the listener’s particular brain-ear system expects, becomes flatter as the frequency lowers due to the wavelength becoming larger than the objects (the torso, head, and pinnae) the sound is diffracting about. These “spectral cues”13 are used by the human ear-brain system, in addition to the ILD and ITD cues, to locate sound sources
Let us consider the case of recording a performer on a stage in a real hall. Using a dummy-head binuaral microphone (or a human wearing in-ear mics) we would capture all three types of cues (the ILD, ITD and spectral cues) on the two channels of the stereo recording. Say the performer is located at an azimuthal angle of 50 degrees to the left of the dummy head. If one measures the ILD caused, at the dummy’s ears, by a sound source located at that location (such calcualtion consists of subtracting the SPL measured at the right ear from that at the left ear) one would find, on the average, about 8 dB (strictly speaking this depends on the distance and frequency, which for the sake of illustration, we would take to be about 10 feet and 1 kHz, respectively). If the performer, while performing (e.g. clapping), moves to the center position facing the dummy head, the ILD would drop to 0. If she moves further to the let, the ILD increases and can easily exceed 8 dB. If she approaches the recording head from the left, the ILD would build up further (due to the enhanced effect of the head shadowing the right ear) and can reach as high as 20 dB if the the performer gets very close to the left ear (since most of the sound will be blocked from reaching the right ear). As a thought experiment, let us record, using the dummy head mic, the performer as she moves (while performing) from the center position to the left position (50 degrees), and then walks to the recording head and whispers in its left ear.
For a stereo playback system to be able to reproduce this entire spatial image accurately from the above-described recording, it must reproduce this entire range of ILD, from 0 to 20 dB at the ears of the listener. We shall now explain why a regular stereo system cannot do so without XTC.
The problem with “regular” stereo playback system (as opposed to one with XTC) is that the maximum ILD it can deliver is that produced by the left (or right) speaker, which for a regular stereo (equilateral) triangle is about only 3-5 dB at 1 kHz (depending on the radiation pattern of the speaker and the distance of the listener from the speakers). This number can be easily verified by putting a test signal (1 kHz sinewave, or pink noise) in the left channel (and only the left channel), measuring the SPL at the left ear and subtracting from it the SPL measured at the right ear. (which can be easily done using sine sweep in BACCH-dSP to produce a plot of the entire ILD spectrum over the entire audio band.). The plot below shows such a typical measured ILD spectrum made with BACCH-dSP through a typical stereo system in the “regular stereo triangle” (+/- 30 degrees) configuration.
The black (red) curve represents the measured ILD spectrum of the left (right) speaker at the ears of the listener. Note that at 1 kHz, the ILD is about 5dB. At higher frequencies, head shadowing (which acts as a “natural XTC”) causes the ILD to rise a bit (as clearely seen in the plot), but the most important content, perceptually, (especially human voices) is below 1 kHz. Therefore, a listener listening to the recording we made above would hear the performer move from the center towards the left speaker, then gets “stuck” at the left speaker as the recorded ILD in the recording builds up above 5dB, since the reproduced ILD at the listener’s ears cannot exceed 5 dB. This should illustrate clearly the fundamental flaw in speakers-based spatial audio reproduction without XTC. [See Footonote14 for an additional, more subtle, flaw].
XTC can remove this limitation. In particular, BACCH can deliver the maximum possible level of XTC (with zero added tonal coloration) for a given pair of speakers in a given room based on a measurement of the two-point HRTF15 of the listener with the calibrated BACCH-BM microphone. The resulting ILD spectrum (which, by definition, is the same as the XTC spectrum) is shown in the figure below for the same audio system:
It should be clear from this plot that BACCH can deliver, for the same audio system, 15 dB ILD at 1 kHz, with ILD levels well exceeding 20 dB, at the ears of the listener sitting in the sweet spot (the location where the HRTF measurement was made.) Therefore, the performer would now be perceived to walk all the way from the center, way past the left speaker, to an azimuthal angle of 50 degrees, then walk towards the listener and whisper in his left ear, much like in the real life event. This is the case irrespective of the location of the speakers, as long as the BACCH filter used during playback was designed for that particular speakers-listener configuration. (Incidentally, BACCH-dSP has a simple easy-to-use binaural recorder that allows you to verify the above by quickly making such a recording of a performer walking around you with the BACCH-BM in your ears, then immediately listen to it through a BACCH filter.)
Now that, we hope, this is all clear for a dummy-head recording, it is easy to explain how a similar enhancement to the accuracy of spatial reproduction can be attained for a recording done with a regular stereo mic pickup.
Type A Recordings:
Stereo recordings done with a "Type A microphone" (ORTF, XY, coincident mic techniques) rely on mic capsules with directional pickup patterns (cardioid, hypercardioid, etc.) oriented in such a way to proportionally attenuate the sound of a source located the right (left) side of the microphone as it reaches the left (right) capsule. Therefore, it is mostly capturing the “ILD” (and in the case of a coincident stereo microphone, only the ILD). Although this “ILD” may be a bit different from the actual ILD a dummy head would capture (since the attenuation imposed by the highly directive capsules may not accurately represent the attenuation due head shadowing), it is fully capable of capturing a good part, if not all, of the wide range ( 0-20 dB) of our proverbial walking performer. Again, a stereo system without XTC will only be able to reproduce a small part of that range (up to about 5 dB) and again, the performer will be stuck at the left speakers as soon as she reaches about 30 degree azimuth to the left, and remains there throughout the rest of the recording, while in real life she was walking well past the angle (to 50 degrees) then towards the left side of the microphones. Again, the same stereo system with the BACCH filter whose measured XTC performance is shown in the plot above, can reproduce virtually the entire range of ILD, and thus can give the listener a far more accurate spatial reproduction of the full spatial image.
The difference between a binaural recording done with a dummy head, and a stereo recording done with Type A stereo microphone, when rendered through the same BACCH filter whose XTC performance is shown in the plot above, is that the one-to-one spatial correspondence between the real image and perceived image is more accurate for the former (since the ILD is coded with the attenuation due to a human head shadowing) than the latter (since the ILD is coded with the particular attenuation due to the directivity pattern of the capsules in the Type A stereo mic). However, they both give a spatial image (through the same BACCH filter) that is far more accurate and realistic than of playback without XTC.
Type B Recordings:
Since "Type B" stereo recording techniques (e.g. spaced omnis) use omni-directional microphones, they rely on spacing the two microphone capsules some distance apart to pick up ITD cues (the captured ILD cues being negligible16). At first look one might (wrongly) suspect that stereo recordings done with such a stereo microphone might not benefit from XTC during playback as much as Type A or binaural recordings, since XTC only affects the level of the sound pressure at the ears. But in fact, the delay between the arrival times of a source’s sound at the left and right capsules of the microphone will not be reproduced correctly at the ears of the listener if crosstalk is present, as explained in the next (long) paragraph.
To understand why this is the case, consider again the performer moving from the center position, where ITD is 0, to 50 degrees azimuth left while clapping her hands. A typical ITD for a source there would be something like 400 microseconds. Now if that recording of the performer clapping at 50 degrees azimuth is played back through a pair of stereo speakers, the level of the clap sound is the same on both channels (because there is little if any ILD captured by the Type B stereo microphone) but the clap on the right channel is delayed by 400 microseconds with respect to the right channel of the recording. Therefore, the sound of the clap will arrive at the left ear from the left channel first, then, after a delay time of t1 microseconds, that same sound wave will reach the right ear (t1 is the ITD that would be caused at the ears of the listener by a source located where the left speaker is located, i.e., at 30 degrees azimuth. It should be clear that t1 would be significantly less than the ITD of a sound source at 50 degrees (400 microseconds)). If, hypothetically, there is no sound from the right speaker, the listener would hear the clap coming from the location of the left speaker (which, at 30 degrees azimuth, is not the correct 50 degree azimuthal location of the real life clap). However, the right speaker will emit the clap recorded on the right channel 400 microseconds after it was first emitted by the left speaker. This same sound will reach the left ear t1 microseconds later (again If, hypothetically, there was no emitted sound from the left speaker the listener would hear the clap coming from the location of the right speaker) causing an ILD of t1, which is wrong in value, and also on the wrong side of the listener! However, due to the Hass precedence effect, the two sounds (emitted from the left and right speakers) are perceived as fused into one, and the ITD caused by the first one (from left speaker) dominates perceptually, as it arrived first, causing the listener to perceive the sound of the performer clapping to be essentially located at the left speaker, which is 30 degrees, and not the correct 50 degrees we seek [see Footnote 17 for a more accurate description of the net effect of the “fusing” of these two sounds].
In contrast, if the crosstalk is cancelled, the left ear (and only that ear) would hear the clap emitted from the left speaker, then the right ear (and only that ear) would hear the clap from the right speaker delayed by 400 microseconds resulting in the correct ITD at the ears, and thus allowing the listener to perceive the correct real-life location of the performer, irrespective of the location of the speakers (again, assuming that the BACCH filter corresponding to that speakers-listener configuration is used).
You can easily verify the above claim that XTC improves the spatial accuracy of Type B recordings using BACCH-dSP: First, make a recording of someone walking speaking or clapping around you while you have the BACCH-BM microphones in your ears. This first recording would be the reference binaural recording. Then make a second recording of the same performance, but this time hold each of the two capsules in each hand, spaced about 6 inches apart. Since the BACCH-BM capsules are essentially omnidirectional, this is tantamount to a "Type B recording" (spaced omnis). After the recrordings are done, play the reference binaural recording while toggling the BACCH filter on and off (which is in BACCH-dSP can easily be done by a tap of the mouse) and observe how the spatial accuracy is greatly improved when the BACCH filter is on. Finally, play the Type B recording while toggling on/off tthe BACCH filter, and you will also hear a significant enhancement in the spatial accuracy when the BACCH filter is on, as discussed above.
In conclusion XTC greatly benefits the spatial accuracy, not only the speakers-based playback of binaural recordings, but also those of Type A and Type B recordings, (and therefore of virtually of all well-made stereo acoustical recordings in real acoustical spaces) as it allows both the ILD and ITD cues to be reproduced more correctly at the ears. If XTC works only for binaural recordings, as some people who have not carefully listened to proper XTC have wrongly surmised, no one would be interested in BACCH, as binaural recordings are a very miniscule fraction of available commercial recordings.
There remains the important question of whether XTC can benefit the spatial rendering of recordings that are produced “artificially” by mixing audio stems (which is the vast majority of popular music). This question is addressed in the following section (to be added very soon).
- How does BACCH enhance the spatial imaging of "studio-mixed" recordings without altering the sound intended by the mixing engineer?
In light of the arguments in FAQ #14 above, we can now address the case of “studio-mixed” recordings, which represent the vast majority of commercially available recordings. In such recordings, the mixing engineer (and sometimes with input from the artist(s) and/or producer(s) and, to a lesser extent the mastering engineer,) concoct an artificial stereo image from stems (most often mono stems) mostly through level panning (and, much less often, time or phase panning) between the left and right channels. Mixing to produce a realistic, pleasing or engaging stereo image is an art involving both technical knowhow and esthetic decisions.
Many mixing engineers are truly ingenious masters. It goes without saying that their final product deserves the utmost respect and that a good hi-fi reproduction system should not degrade or fundamentally alter their construct. It is also very true that virtually all commercially available mixed recordings were mixed while monitoring on monitors without XTC.
Depending on the techniques used and esthetic decisions made, these concocted recordings range over a wide spectrum: on one end of the spectrum are recordings aiming to emulate a real acoustic environment (e.g. a jazz club). Let us call this end of the spectrum the “pseudo-realistic end”. On the other end of the spectrum are recordings that have no binding ties to realism, and instead aim to evoke sensations, or project certain esthetic expressions (e.g. the chimes in Pink Floyd’s well-known Time track on their Dark Side of the Moon album). Let us refer to this end of the spectrum as the “artificial end”.
We will now consider what happens when such recordings are played back through XTC.
On the pseudo-realistic end of that spectrum, most of the arguments made in FAQ#14 above hold, to some extent, since the mixing engineer is essentially using at least an analog of ILD and ITD to produce a “realistic” stereo image like a stereo mic would, and all that XTC does is remove the artificial cieling on the ILD and ITD limits imposed by the speakers during playback. Most relevant in this context is reverb. During mixing, reverb is added algorithmically or through convolution with a real space impulse response (with the latter technique yielding far more realistic reverb). In both cases XTC unlocks the perceived reverberation from the speakers and project it into 3D space. It does so because the perception of a realistic 3D reverb is caused by late reflections (the diffuse field) arriving at the left and right ears at almost random arrival times (i.e. with low L-R correlation, in the parlance of acoustics) and without XTC the sound at the right and left ears would be highly corelated since the sound from each of the L or R channels reaches both ears. Such highly L-R corelated sound causes the listener to perceive the reverb to be largely restricted spatially a region that is mostly where the speakers are. It is hard to imagine a mixing engineer who would object to his mix reproduced with a reverb that is more 3D and less “stuck to the speakers” (as long as the tonal and level balance between the direct and reverberant sound is not altered. (BACCH is a patented form of advanced XTC that causes no alteration whatsoever to that balance as described in this standard, but highly technical book chapter.) In fact, one of the most noticeable and striking aspects of listening through a BACCH filter for the first time is the immediate sense of being in a real 3D space due to the higher L-R sound decorrelation that reverb is meant to cause at the ears.
On the “artificial end” of the studio-mixed recordings spectrum defined above, the mixing engineer concocts an image whose panned sources constitute an artificial stereo image that does not aim to be a reflection of a reality, but rather an esthetic or artistic construct. While mixing that image the engineer is choosing to place sources in a space that is largely between the two speakers. However, as is well-known by audiophiles, even a stereo playback system without XTC can image in a 3D, albeit relatively restricted, spatial region around the speaker (often called “the soundstage”). The main reason such imaging occurs without active XTC is because the listener’s head, by shadowing the contralateral ear from the loudspeaker (i.e. the speaker on the opposite side) creates a natural crosstalk cancellation that is highly effective at higher frequencies (i.e. frequencies whose wavelengths are smaller than that of the human head). It should be clear that this natural XTC (which can be seen in the measurement shown in the first plot in FAQ#14) depends on the span between the speakers, the distance between the head and the speakers, the radiation pattern of the speakers, and the extent and relative strength of reflections in the room. A larger speaker span, a shorter distance to the head, a more directive speaker, and a higher ratio of direct-to-reflected sound, all lead to higher values of this natural XTC. This is mainly why different stereo systems in different rooms with different listener-speakers placements, can achieve different levels of “3D imaging”.
A mixing engineer in a given studio with a certain set of stereo speakers concocts a stereo image while hearing a soundstage the spatial extent of which depends largely on the above listed parameters of the particular monitoring setup in the studio. An audiophile playing back the resulting recording through a good hi-fi stereo system at home has generally no way of knowing what these parameters were when the mix was produced, but still strives to get a good measure of a 3D soundstage. Indeed “3D soundstage” imaging of a playback system is one of the holy grails for audiophiles and audio critics. By choosing and tuning his gear and listening room to enhance such soundstage the audiophile does not betray the intent of the mixing engineer as long as the enhancement of the spatial extent of the soundstage does not come at the expense of a change in the spatial balance or tonal content of the recording during playback. It is very possible that the 3D imaging of an audiophile’s playback system has significantly better 3D imaging capability than that used by the engineer while monitoring the mix. No one would object if this were the case, or accuse the audiophile of betraying the engineer's intent.
For such recordings (on the “artificial end” of the spectrum,) XTC cannot pretend to enhance realism during playback since the stereo image was artificially concocted in the first place. However, like in the case of natural XTC, adding more XTC actively to enhance the spatial extent of the soundstage, without altering the balance or tonal content of the recording, (which is the essential characteristic of BACCH XTC) does not strictly betray the intent of the mixing engineer since the spatial extent of the artificial soundstage was not prescribed by him. Of course, this argument becomes more tenuous if XTC leads to extreme spatial panning, which can only happen for hard left or right panned sources in the absence of reflections (e.g. in an anechoic chamber, a hard left or right panned sound source played back through a pair speakers with high levels of XTC, without any ILD or spectral cues added to the sound, would lead to the sound being perceived to be very close to the left or right ears of the listener, as if wearing headphones). Such extreme imaging does not occur in real listening rooms with typical levels of direct-to-reflected sound ratio.
Of course, the level of active XTC during playback can be dialed down (in BACCH-dSP there is an “XTC percentage” slider that allows doing just that) but it should be clear from the above arguments that this is not recommended for acoustic recordings or for recordings on the “pseudo-realistic end” of the “studio-mixed” recordings spectrum. Moving towards the “artificial end” of the spectrum, the question of betraying the original intent of the engineer does indeed become a valid objection, but only to the extent to which XTC alters the tonal character and spatial balance of the recording (which BACCH, by design, does not do at all) and to the extent to which high levels of XTC can result in jarring extremely panned images, which can occur with BACCH but only in near-anechoic environments and with recordings having extremely panned mono images. The latter issue can be addressed by dialing back the XTC level (or in extreme but very rare cases, by bypassing XTC!).
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Dr. Edgar Choueiri explains BACCH
- Thread starter jimbill
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Tim Link
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I have found for myself that the main benefit of crosstalk reduction is reduction of comb filtering of center panned images, which is often where the lead vocalist or instrumentailst is placed. At trade shows with standard stereo setups I avoided the sweet spot because of this. I find the tone to be better by sitting next to one speaker or the other. For stuff panned to the sides, plain old two speakers stereo works great for me, pretty much does just what I want. The stereo special effects you can get with XTC are interesting but I get bored with that over time. I don't need that much spacial realism, although it is fun on occasion. My solution is to use a center tweeter for center panned sounds. It's in the highs that all the comb filtering happens with regular stereo. My "tweeter" horn goes down to 600Hz, and there are side flanking difference tweeter horns to cause high frequencies not centered in the sound field to get panned across the sound field accordingly. My goal is basically the sound of regular two channel stereo with widely spaced speakers,but with no stereo induced comb filtering of the image center.
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I am perplexed on one point.
The 90% of the music is mixed on stereo monitors without crosstalk cancellation / reduction.
And the mixing engineer tweaks (among other things) spatial information based on what he hears with that system.
So if this technique is applied after in replay system the result is less faithful to the master than it should...
Instead, it could work where mixing was done with headphones.
Therefore it seems to me more of an effect like a saturator or exciter... something that simply alter the sound in a specific way.
Is it worth to spend all that money for this? Just a doubt...
The 90% of the music is mixed on stereo monitors without crosstalk cancellation / reduction.
And the mixing engineer tweaks (among other things) spatial information based on what he hears with that system.
So if this technique is applied after in replay system the result is less faithful to the master than it should...
Instead, it could work where mixing was done with headphones.
Therefore it seems to me more of an effect like a saturator or exciter... something that simply alter the sound in a specific way.
Is it worth to spend all that money for this? Just a doubt...
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Tim Link
Addicted to Fun and Learning
This is an important point. But I think that a lot of recordings are just made the sound as good as they can despite the cross talk and I don't think they actually do anything to try to count for it. I've talked to people who mix and master and they told me they don't do any tonall adjustments two compensate for it. But it may have an effect on the soundstage width and this may be an issue if someone wants to hear that just the way it was mixed and mastered. One thing I think I hear sometimes is that crosstalk cancellation will really bring the close mic"d center panned vocalist or instrumentalist to the front. So sometimes it might sound better to turn it off. I never do though. I should point out that I'm not using BACCH but something similar.
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Imagine a music track which includes two sound sources hard panned to left and right side. When you listen to it by a stereo speaker setup they play left + right but still in front of you due to the speaker position and the crosstalk. Applying BACCH or crosstalk cancellation will now move these sound sources more outside promising a "more natural" playback..
Listening to the same track by headphones can quickly give you the feeling of pressure at left + right ear by the two sound sources. It is funny that now some headphone processig introduces crosstalk to move the hard panned sound sources away from hard panning with the target to get a "more natural" playback
Listening to the same track by headphones can quickly give you the feeling of pressure at left + right ear by the two sound sources. It is funny that now some headphone processig introduces crosstalk to move the hard panned sound sources away from hard panning with the target to get a "more natural" playback
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Tim Link
Addicted to Fun and Learning
This is why I mostly focus on getting a solid center without comb filtering and not so much on a super wide soundstage. Indeed, it is strange to have a hard panned sound come completely from the side rather than off to the side but still in front of you. So it depends on the recording. Some of them really blossom into something fantastic when the cross talk is completely eliminated. Others get out of control. So it's definitely something you want some control over. In any case, cross talk sets a hard limit on things. If a recording requires crosstalk to sound its best, then that means to me it's one of those recordings that is only capable of so much in terms of sound staging. I'm thinking Mama's and Papa's. And then there's mono recordings which I think do sound better with crosstalk reduction in terms of tone but nothing happens in terms of soundstage.Imagine a music track which includes two sound sources hard panned to left and right side. When you listen to it by a stereo spealer setup they play left + right but still in front of you due to the speaker position and the crosstalk. Applying BACCH or crosstalk cancellation will now move these sound sources more outside promising a "more natural" playback..
Listening to the same track by headphones can quickly give you the feeling of pressure at left + right ear by the two sound sources. It is funny that now some headphone processig introduces crosstalk to move the hard panned sound sources away from hard panning with the target to get a "more natural" playback
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If it helps in your doubts: I would be amazed if Amelio, Kongshaug or any other engineer of any ECM record, having listened their work reproduced with or without Bacch would prefer the latter. The very least you can expect with almost any decent stereo recording is a sudden spatiality, depth and steady positioning of each individual instrument you probably never heard before. Those were supposed to be the main benefits of my maggies (and they are, compared with almost any other speaker i have had), but even them pale in these aspects compared with bacch feeding it. Even when the effect is subtle, you go back to normal stereo and… it sounds like mono recordings. Personally i’m more interested in this than the fireworks of 180+ degrees span you get with some recordings (and we are not even talking about binaural ones). Which are nice also..
i had a problem with my setup and had to wait a couple of days for Edgar to fix the issue. The longest days i’ve experienced this year. Bacch is a delicious drug.
Finally, many of you have dimished this as yet another xtc attempt. It is not: this is order of magnitudes more sophisticated, and it truly doesn’t colour the signal (even more, with orc it fixes the colourations added by your room).
After almost a year using it, i can assure B4M is by far the best investment in audio i have ever made.
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If you are not using BACCH4Mac then you are not hearing the same thing. I don't think there is anything out there that is similar. But prove me wrong, do a side by side comparison.
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Yes, technically we can justify the "effect", although it is not necessarily better than normal stereo.
But if you charge me a few hundred euros I can also justify the cost.
If this system costs more than an Atmos 7.2.4 bundle what's the point? Shouldn't this be more spatial?
But if you charge me a few hundred euros I can also justify the cost.
If this system costs more than an Atmos 7.2.4 bundle what's the point? Shouldn't this be more spatial?
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Tim Link
Addicted to Fun and Learning
I'll try it! I see it's a 14 day free trial for the plug-in, and I can run that in my pipeline easily. It'll only tell me part of the story because I won't have the extras to dial it in to the max. For the price of just the plug-in alone, they must feel it works exceptionally well even without the extras.
What other crosstalk reduction methods have you tried? I've used Soundpimp, some plug-in that used to be available for Chrome browser, my own recursive crosstalk using a series of delays and attenuations, a physical barrier, and my current 3 speaker setup. I've also used Polk SDA, and a method that involves nearfield speakers that are attenuated and delayed to create the crosstalk reduction. So far my favorite in terms of sound quality is the actual physical barrier. But that's from memory, and it's been a long time since I've heard a barrier setup that was dialed in well. Oops, I forgot to mention Carver Sonic Holography. I had a pre-amp that did that too.
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- #11
I'll be interested in hearing your thoughts. I haven't heard anything else. I came across this by chance and started reading up on it. I'm not a true audiophile, in that, I rarely change gear and have no background in the scientific side of audio.
I started with the basic and after about 3 months, upgraded to the Audiophile. Now I have a hard time listening to regular stereo. I have a pretty nice system and as far as my experience goes, this was the biggest change I've purchased other than my speakers.
One thing you can look forward to is having a conversation with Edgar. He is a scientist and a professor through and through.
I started with the basic and after about 3 months, upgraded to the Audiophile. Now I have a hard time listening to regular stereo. I have a pretty nice system and as far as my experience goes, this was the biggest change I've purchased other than my speakers.
One thing you can look forward to is having a conversation with Edgar. He is a scientist and a professor through and through.
Justdafactsmaam
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I still hold that the “effect” is the crosstalk and we have learned to live with it and the very low glass ceiling in terms of a stereo system’s ability to suspend disbelief that comes with it. The crosstalk removed by the BACCH is not on the recording.
Better is subjective. The biggest hurdle between stereo recording and playback and live acoustic music in a concert hall is the accurate recreation of spatiality of that original performance. The BACCH solves that problem in so far as a given recording has the spatial information in it. Whether or not that is considered “better” is in the ear of the beholder.
With that said it definitely is more accurate.
The point is arguably the greatest breakthrough in home audio since the advent of home stereo. Of course that is subjective. But I consider it to be far and away the best money I ever spent on audio. YMMV
I will admit that the idea intrigued me. Then I looked up the price and lost my intrigue.
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- #14
There is no getting around that it is expensive. Not everyone can afford to spend $5,000 on the program and associated equipment (plus a Mac computer if you don't have one). But for people that can afford to spend that much on a new amplifier, cables, and turntable, they will see a much bigger return on listening enjoyment with BACCH.I will admit that the idea intrigued me. Then I looked up the price and lost my intrigue.
The plugin at $980 is much cheaper, but if you're like me, you'll start craving the full deal with the headtracking.
The unit I saw was like $50K. $5K is big, but not totally out of the realm of possibility.
No Mac, and that's pretty much a deal-killer for me. Still, I'd love to have a chance to hear the tech.
Keith_W
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You can download uBACCH (the Windows VST) from BACCH Labs and try it for free for 14 days. That was what convinced me. If the price of uBACCH is still excessive, there is also X-talk Shaper from Home Audio Fidelity. I haven't tried HAF's version.
Well, it’s not an “effect”. It‘s the unveiling of what is already buried in our records. The degree of increased realism in the reproduction seems hard to believe many times.
An example: this month i’ve been reading rave reviews in several magazines about a new recording of the Takacs quartet playing a couple of Schubert quartets (#15 & 8, Hyperion). Last night I tried it (Roon/Tidal). It was just draw jopping… ! you can almost touch the cello, viola and violins. Close your eyes and you would swear you are in the concert hall, second row. Take bacch out and still sounds very good, but … just a very nice stereo in your home. Not even close to those magic moments before. In very few of the hundreds of live camera music concerts i have gone for decades i had such an insight of what the composer intended, being so deeply, emotionally involved with the music. Perhaps only when at center of first rows, and then only at the better acoustic venues….
Why this and not atmos: because instead of a few hundred, you have millions of recordings to discover. And I guess even at the cost of it (high, I agree) is a fraction of what you would pay for a quality atmos system. Using the stuff you already have.
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Justdafactsmaam
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Sorry to contradict you but crosstalk actually is in the recording (mixing) in a certain sense, unless the mixing engineer used headphones or a system with crosstalk cancellation (obviously not, because he knows practically no one is using it).
So there is no magically hidden spatial information, just unintended information. As I can see it.
This doesn't mean that reducing crosstalk is harmful, on the contrary, I suspect that it has a certain benefit in rendering the soundstage.
But this effectively makes the crosstalk reduction technique a pure effect. Just as the introduction of crossfeed in headphone listening to overcome the opposite problem is an effect. IMO
The greatest fidelity to the true event is mental paranoia. This concept does not exist, simply because the capture and reproduction of sound in stereo recordings is limited with respect to spatial information. And reducing crosstalk does not mean introducing what it has not captured. This is why binaural actually exists.
Therefore, from my point of view, considering breakthrough a spatial enhancer effect that cost so much is not easy...
Let's be clear, it's not a question of discrediting anything or anyone, but simply of correctly framing the product from a technical and also commercial point of view. I'm open-minded in this sense.
I would like to try it on my system, but even if it did miracles I would not buy it on principle at that price. It would mean that all systems without it are bad projects, but they are not. It is the principle of stereo since its conception.
To wit... there are spatial effect plugins that cost 25$ and are based on highly refined technology and principles (ex. Nugen Stereoizer working with ITD / ILD algorithm).
Clearly they do not do the same thing, but if we consider only the subjective effect for the non-binaural traces in a certain sense it could be.
Unfortunately I believe that the discussion goes on the subjective preference so it also becomes useless to discuss... It's a bit like loudness compensation.
By varying the listening volume, the frequency response of our hearing changes. There are some incomplete studies that indicate how our hearing varies in this sense, on which basis some compensation function was developed.
This functions are an effect, like crossover reduction. You do not know at what volume the master was created so it is useless for you to obsess in the search for perfection in this sense.
There are those who use this compensation and are happy, there are those who do not use it and are equally happy.
It's a matter of preferences, after all.
But loudness compensation is clearly not the revolution of the century. It just tries to solve one of the many problems that afflicts reproduction. In fact where it exists it doesn't cost thousands of dollars...
But we can also add the frequency response target of the system. There is no more correct target than another. It is simply not possible to determine it. Some trends exist but it go to preference in the end.
It's all about recreating a realistic sound without having the necessary information about that sound (unless it is a purely binaural recording, but I suspect they are a small part).
So what is the reason to pay so much trying to do this?
With that money I could go to live events all my life.
Obviously... that's my point of view. I'm not saying it doesn't produce a greatest effect.
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Justdafactsmaam
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No worries. I am used to it on this forum ;-)
It’s definitely not in the recording. No sense about it, nothing subjective. It’s a fact. What the mixing or recording or mastering engineer/engineers heard separately and/or collectively is unobtainium. Not just what they heard but what they intended and what they thought. And it is no secret to any artist/producer/engineer that once the recording is released it will be played back on any and all sorts of systems from shopping mall PAs to ear buds to high end audio systems. There simply is no standard.
Whether we use a bias motivated label of magical, unintended or any other charged language, spatial cues that are masked or confused by cross talk and room reflections are present to some degree or another on every stereo recording. What we do with it is up to us.
You suspect it has a certain benefit? It can turn a very good stereo recording into a concert hall experience. Which *I* think is a wonderful thing. YMMV
Removing something from the playback that is not present on the recording is not an effect. Adding something that isn’t present on the recording is an effect. And more so it often ends up being a semantic argument against the “legitimacy” of crosstalk cancelation in a “true high fidelity” playback system.
You can’t fault the playback system for flaws in the recording. The reality is with the ideal stereo recordings the fidelity to the original event is approaching perfection.
Whether or not it’s worth the money is a personal matter for any audiophile. But you definitely can’t judge the results without a proper audition. And it looks as if your point of view is missing that experience.
Good and bad are subjective. IME conventional two channel stereo seemed quite good at its best but always was pretty bad next to live acoustic music in a good concert hall.
IMO the gap between conventional stereo and stereo with the BACCH is about the same as that between conventional stereo and live acoustic music.
Or to put it another way. For me, having liv ed with the BACCH, conventional stereo is not good.
I haven’t auditioned them so I can’t comment on their merits.
Indeed preferences are subjective and inarguableUnfortunately I believe that the discussion goes on the subjective preference so it also becomes useless to discuss... It's a bit like loudness compensation.
By varying the listening volume, the frequency response of our hearing changes. There are some incomplete studies that indicate how our hearing varies in this sense, on which basis some compensation function was developed.
This functions are an effect, like crossover reduction. You do not know at what volume the master was created so it is useless for you to obsess in the search for perfection in this sense.
There are those who use this compensation and are happy, there are those who do not use it and are equally happy.
It's a matter of preferences, after all.
But loudness compensation is clearly not the revolution of the century. It just tries to solve one of the many problems that afflicts reproduction. In fact where it exists it doesn't cost thousands of dollars...
But we can also add the frequency response target of the system. There is no more correct target than another. It is simply not possible to determine it. Some trends exist but it go to preference in the end.
It's all about recreating a realistic sound without having the necessary information about that sound.
So what is the reason to pay so much trying to do this?
With that money I go to live events all my life.
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