What is hx pro

THD stays the same as before. Since poor highs are far more objectionable than higher THD to most consumers, this is the approach chosen by most manufacturers. We set bias a bit higher to lower overall distortion and possibly improve MOL, and we get a smidge of HF improvement. In practice, HXP was most often used to improve the HF performance of mediocre 2-head decks, though it can indeed have an audible and significant effect on better decks.

As far as why one would want to turn it off and not use it, no one has made a credible argument to me as to why one would want to do this. It's kind of like being able to change the MPG of one's car without penalty. If you can, why wouldn't you get two more MPG? Arguing that the MPG of the car is "good enough" does not convince me. Factory technician for both Yamaha and JVC. Sonics consultant for Denon. Pacific Stereo store manager, service manager, Central Service lead tech, liquidator at our demise and owner of what's left.

Pacific Stereo curator. Authorized servicer for virtually every brand on the planet at one time or another. Music addict. Industry-respected ears. Head Tapehead. I know, right? Find all posts by Pacific Stereo.

Engineers have provided HXPro select switches on decks to enable users to allow adherence to pre-HXPro implementations when using higher end, better performing tape. It's no more complicated than that. In other words, if you are using a super metal as one primary example and you aren't trying to push the living sh! In some cases it can mess with the response curve of the recording. HXPro has the primary goal of achieving higher gain whilst minimizing distortion as you push the levels ever close to a tapes saturation point, and it does so by utilizing high freq content as a bias component - the high freq bias component of the input signal that is already present in recording loop.

One of my posts in the "wiped" bucket suggested doing some comparisons between having HXPro in the loop and out of the loop - using a hybrid type II or a super metal. I've done these comparisons and I personally find that having HXPro off when using Metal Masters produces better high-freq tracking results and minimizes low end bump for the recording levels I employ. It's a subjective assessment, I know, but it is clearly defined in user manuals for Sony three-headers; punch it in and out during recording sessions and monitor the effect.

It effects overall playback equalization but the bigger question is, can the listener perceive it? Even more so, does the listener prefer one way or the other? For more run of the mill type I, type II and type IV stock, HXPro helps to achieve higher output fidelity - translated - louder recordings with lower distortion. Better tapes don't need it. Again, HXPro helps mediocre record loop, circuit designs AND the more mediocre grades of tape perform better when the end result is to minimize distortion when pushing levels closer to the max - for a given tape.

The decks that employ it with no switch need it all the time Nak never used it for that very reason - even on their lower tier decks. Originally Posted by BlazeES. Originally Posted by perry. I don't think it is a cost vs performance design in this case. Perhaps they employed it for lower THD all the time? I do not know the incentives both inventors had, but like others before them, they reached similar solutions, the difference between Dolby HX and BO HX Professional, being just a matter of numbers it's not 6dB it's 12; it's not 10kHz it's kHz and so on.

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For additional information, see the Global Shipping Program terms and conditions - opens in a new window or tab. Estimated between Wed. Please note the delivery estimate is greater than 10 business days. Likewise, quiet passages will not be expanded until after they are detected. These delays give rise to an audible problem often called "breathing".

For example, if there is a 2dB dip in frequency response at 1kHz in the tape recorder, this will be accentuated to a 4dB dip if the compressor is using a ratio. For that reason and the previously mentioned breathing, some people prefer to use their recorder without any noise reduction at all. They prefer a bit of noise to the other errors. Dolby HX Pro is not noise reduction and does not use compression or expansion.

HX Pro is a technique developed by Dolby Labs to increase tape headroom by decreasing the bias when recording signals with a large high frequency component. This was a complex feed forward system that measured the frequency content of the music, calculated the bias required and added this level of bias to the input signal.

While the system functioned better than a fixed bias system, it was not the optimal solution. But he took a different approach to correcting the problem and in the process got a bonus in performance.

He deduced that the high frequencies of the music being recorded were in fact acting as additional bias for the music itself and thus degrading performance. Experimenting with various kinds of music, he devised an algorithm for the bias equivalent added by the high frequency content of the input signal. It was then a relatively simple matter to construct a feedback system that reduced the bias by precisely this amount, on a real time basis.