Based on the limited descriptions that are available, QOL and X-Drei seem to me to be intended to do two completely different and unrelated things.
QOL appears to be intended to somehow extract/recover/restore information, apparently phase-related, that "is already present in recordings, but [is] hidden in conventional reproduction."
X-Drei appears to be intended to reduce, modify, or otherwise make more benign, ultrasonic and rf frequency components of the signal, that might be difficult for the power amplifier and/or the speakers to handle without audible side-effects. In looking at the signal waveforms shown in their writeups, keep in mind that what distinguishes the sinusoidal, triangular, and square waves that are depicted as inputs are high frequency harmonics. Although they don't show time scales in any of the diagrams, those harmonics are presumably at ultrasonic and rf frequencies, because presumably the device would not be designed to alter harmonics or other spectral components that are below 20 kHz.
I would therefore expect the effects of X-Drei to be highly dependent on the particular amplifier and speakers that are being used, and on how gracefully they would be able to handle those ultrasonic and rf spectral components in the absence of this technology.
IMO.
Regards,
-- Al |
Hi Al, that's a really helpful comparison of the effects of both units.
Since they work on different facets of the signal, what is your hunch as to how they might work in series ie one after the other between pre and pow? And if you feel this might be positive which sequence would you choose?
Thanks for your time, Marc. |
Almarg, I would be interested in your opinion of the QOL's oscilloscope data as provided on the BSG website. Others have speculated that it's a middle/side phase processor similar to devices used in mastering process. |
The lack of detailed technical information on what these devices are doing makes saying anything about them very speculative, at least without hearing them (preferably on multiple systems). But fwiw: 02-15-12: Spiritofmusic
Since they work on different facets of the signal, what is your hunch as to how they might work in series ie one after the other between pre and pow? And if you feel this might be positive which sequence would you choose? I suspect that each would have its effects independently of the other, and regardless of whether or not the other is present. Along the lines of my earlier comment, based on the available information I suspect that the effects of the X-Drei would be more system dependent than the effects of the QOL. If both devices were present, my instinct would be to put the X-Drei first in the chain. Putting it somewhat simplistically, I envision the X-Drei as "cleaning up" the signal, and the QOL as adding something to the signal. So it would seem to make sense for the QOL to operate on as "clean" a signal as possible. 02-15-12: Onhwy61
I would be interested in your opinion of the QOL's oscilloscope data as provided on the BSG website. I agree with your comment in the current QOL thread, which essentially says that the device is definitely introducing a significant stereo component onto the mono signal. As you may realize, the oscilloscope display is what is known as a Lissajous pattern, with one channel (left or right) driving horizontal deflection and the other channel driving vertical deflection. The QOL device clearly causes the two channels to become significantly different. Not enough information is presented to be able to say much more than that. Regards, -- Al |
Thank you, Al. The X-DREI appears to be subtractive, whereas the QOL may be additive. As a result, I think it may process the signal less than the QOL which on another thread is possibly revealed to be a mid-side processor.
I think that if anomalies such as square waves in the ultra HF range are smoothed to correct sine waves this may reduce unnecessary load on the power amp/speakers and improve 'intelligibility'.
As a result I am tending towards the X-DREI since 2 units in series may be overkill. |
So, the X-DREI merits so little discussion (your comments, Al, notwithstanding) as compared to the BSGT QOL which has had a TON of comments.
I'm a little confused as to how 2 units which claim to have such a fundamental improvement to sound quality and sit in the audio chain in the same place ie between pre and pow can have such varying interest levels from A'goners.
Both are obtuse in explaining their effects, and both have had limited reviews (X-DREI in 6moons, QOL in TAS), but X-DREI experience amongst listeners seems to be much rarer than the QOL.
A'goners, please post thoughts or this thread will go the way of the Dodo!
Marc |
Blumlein laid out a lot of the fundamentals of stereo recording decades ago. He seems pretty spot-on; the closer one adheres to the basic principles, it seems, the better the sound.
I guess I still have to be convinced about the QOL.
With regards to the X-DREI, some equipment will benefit and others will not. I suspect this will have a more dramatic effect on solid state amplifiers, as RF switching is a bane of such amps, and something that could limit that might be really helpful if the amp has that sort of bandwidth to begin with. Tubes don't have switching issues so I suspect the X-DREI will have less effect on them, but its just a guess, the proof would be to give it a listen. |
I guess that I'm commenting on the lack of user comments on A'gon. The X-DREI has had same overall limited coverage as the QOL (1 review each, minimal advertising), both promise substantial improvements over regular signal, but QOL ends up getting momentum of interest and X-DREI...nothing.
Surely all the QOL proponents should also give this unit some consideration. Note, I am not affiliated in any way with product, just getting my head around whether X-DREI or QOL, or indeed neither is way to go.
Will trial device in Summer myself. |
Qol is advertising; is x-drei? |
Just my opinion of course but I really feel like the less processing you can do, the better. To that end, audio equipment should be RF resistant and phase coherent. |
BSG has done a stellar job in marketing the QOL. They took a process that should have zero audiophile appeal and fashioned it in such a manner that it is now the hot audiophile product. Imagine if they had offered the QOL as a mid/side stereo width control? Instead they pitched it as a "signal completion" device and talked about recovering hidden phase information. This obscures what the device really does, but it sounds pseudo-plausible and at least it's readily repeatable. BSG is also smart enough to realize that for some audiophiles it's preferable, it might even be mandatory, for the operating principles of a product to not be understandable, or at least operate under some unknown, newly discovered process. It's the antithesis of the if it measures good... school. Then there's the review in TAS. A feature review by the magazine's editor for a new company with a single product is quite a coup.
BSG should be applauded for bringing to audiophiles the benefits of mid/side processing. |
There's a really vigorous debate on the dedicated QOL thread. The majority of listeners are positive on sound improvement delivered by the unit, but others are skeptical, and a few have surmised it is a mid-side processor (a process most audiophiles incl. me weren't even aware of). This is backed up a mid-side expert on the Audionervosa forum who claim to replicate it's effects with proprietary studio mastering equipment.
Listeners who like the unit have really taken offense to this possible revelation about the QOL, and I agree most wouldn't have gone for it had this aspect been alluded to.
I've invested in a SpatialComputer Black Hole to help with bass nodes/standing waves, and even though their website is a little uninformative, enough of the principle was explained that I knew I wasn't buying into a 'secret' process.
The point of this thread is to get opinions on the X-DREI which really doesn't seem to have developed anywhere near the same profile as the QOL.
Again their website is obtuse, but enough of their explanation seems to make logical sense as to the purpose of manipulation of unwanted square and triangle waves which undoubtedly contribute to HF hash in the signal emerging from the spkrs. |
