Κώστας Φ.
Truth hurts. Here's a teddy bear.
- Μηνύματα
- 8.978
- Reaction score
- 894
Ίσως θυμάστε το Ε-trap, μία ενεργή μπασοπαγίδα με DSP για την οποία μας μίλησε ο xfader εδώ.
Η βασική ιδέα δεν είναι καινούργια.
Έχει κατοχυρώσει σχετική πατέντα από το 1990 ο Nelson Pass (US Patent 4,899,387) για το Shadow Active Low-Frequency Acoustic Control της Phantom Acoustics.
Το προϊόν ήταν ήδη στην αγορά από το 1989.
Διαβάστε το σχετικό review του Stereophile, από τον Robert Harley, εδώ.
Τα σχόλια ήταν παραπάνω από θετικά.
[Tόσο θετικά που οι τύποι, μόλις διάβασαν το review - προ της δημοσίευσης - αποφάσισαν να αυξήσουν κατά 40% την τιμή του προϊόντος - και φυσικά τους έκαναν "ρόμπα" στο Stereophile "happy_1" ...]
Σήμερα ένας καλός Κύριος ανακάλυψε πρόσφατο άρθρο του Stereophile που επανέρχεται στο θέμα.
Μιλάμε πάντα για την ενεργή διόρθωση χοντρών προβλημάτων που υπάρχουν στους περισσότερους χώρους και τα οποία οι υπάρχουσες λύσεις δεν τα "ακουμπάνε", είτε γιατί δεν μπορούν (Lyngdorf, Copland etc.) είτε γιατί δεν θέλουν (βλ. Meridian).
Το άρθρο είναι απλό και κατανοητό ενώ περιέχει και τα αποτελέσματα από τις δοκιμές του συντάκτη (Keith Howard). Αξίζει να το διαβάσετε.
"Recently, I assessed four disparate room-correction systems based on digital signal processing (DSP): Copland DRC205, Lyngdorf Audio RoomPerfect, Velodyne SMS-1, and Meridian DRC. I concluded that Meridian's approach—which applies IIR (Infinite Impulse Response) "anti-resonance" filters to suppress room resonant modes, if only partially—was, in many respects, the best. What I particularly like about Meridian DRC is that, unlike the Copland and Lyngdorf processors, its approach to system tonal balance is largely hands-off. Yes, it lightens up the extreme bass a little, as you'd expect, but it doesn't recast the system balance in any way that might prove undesirable. If you like your system's tonal character as it is, Meridian DRC behaves just as you'd want a room-correction system to behave: it quells room resonance effects while leaving the system's essential sound well alone.
Nevertheless, I was left questioning whether this approach to electronic room acoustic correction—of using the main speakers to provide the correction as well as reproduce the music—is the optimal one. As the Meridian system's developers themselves acknowledged in an AES paper describing its operation (footnote 1), there is a limit to how much correction can be applied this way without imposing undesirable effects on the speakers' sound. Whether this limitation permits or prevents the optimal correction being applied is unclear, but any such restriction is obviously a concern. Plus, there are limits to what can be achieved when, as with the Meridian system, the microphone is placed only at the listening position during the setup process."
...
A superior solution might require a different approach to electronic room correction. Instead of asking the main speakers to apply room correction as well as reproduce the music, we could instead add a third speaker, perhaps more, whose only task is that of applying modal correction. In effect, such a speaker or speakers would provide active modal absorption and offer two principal benefits. First, there is no question of the room-correction signals having an undesirable effect on the main speakers' direct sound. Second, these active absorber(s) can be positioned in one or more room corners, where they can most effectively couple to and so control room modes. If we then also change the setup routine, so that it is able to detect every room mode, we might arrange to kill the room's fundamental width (or length) mode entirely, thereby eliminating the problem of the room's centerline notch."
Διαβάστε ολόκληρο το άρθρο: Stereophile.com
Η βασική ιδέα δεν είναι καινούργια.
Έχει κατοχυρώσει σχετική πατέντα από το 1990 ο Nelson Pass (US Patent 4,899,387) για το Shadow Active Low-Frequency Acoustic Control της Phantom Acoustics.
Το προϊόν ήταν ήδη στην αγορά από το 1989.
Διαβάστε το σχετικό review του Stereophile, από τον Robert Harley, εδώ.
Τα σχόλια ήταν παραπάνω από θετικά.
[Tόσο θετικά που οι τύποι, μόλις διάβασαν το review - προ της δημοσίευσης - αποφάσισαν να αυξήσουν κατά 40% την τιμή του προϊόντος - και φυσικά τους έκαναν "ρόμπα" στο Stereophile "happy_1" ...]
Για την ιστορία, η λύση αυτή δεν έτυχε της αποδοχής που θα περίμενε κανείς.
Σήμερα ένας καλός Κύριος ανακάλυψε πρόσφατο άρθρο του Stereophile που επανέρχεται στο θέμα.
Μιλάμε πάντα για την ενεργή διόρθωση χοντρών προβλημάτων που υπάρχουν στους περισσότερους χώρους και τα οποία οι υπάρχουσες λύσεις δεν τα "ακουμπάνε", είτε γιατί δεν μπορούν (Lyngdorf, Copland etc.) είτε γιατί δεν θέλουν (βλ. Meridian).
Το άρθρο είναι απλό και κατανοητό ενώ περιέχει και τα αποτελέσματα από τις δοκιμές του συντάκτη (Keith Howard). Αξίζει να το διαβάσετε.
"Recently, I assessed four disparate room-correction systems based on digital signal processing (DSP): Copland DRC205, Lyngdorf Audio RoomPerfect, Velodyne SMS-1, and Meridian DRC. I concluded that Meridian's approach—which applies IIR (Infinite Impulse Response) "anti-resonance" filters to suppress room resonant modes, if only partially—was, in many respects, the best. What I particularly like about Meridian DRC is that, unlike the Copland and Lyngdorf processors, its approach to system tonal balance is largely hands-off. Yes, it lightens up the extreme bass a little, as you'd expect, but it doesn't recast the system balance in any way that might prove undesirable. If you like your system's tonal character as it is, Meridian DRC behaves just as you'd want a room-correction system to behave: it quells room resonance effects while leaving the system's essential sound well alone.
Nevertheless, I was left questioning whether this approach to electronic room acoustic correction—of using the main speakers to provide the correction as well as reproduce the music—is the optimal one. As the Meridian system's developers themselves acknowledged in an AES paper describing its operation (footnote 1), there is a limit to how much correction can be applied this way without imposing undesirable effects on the speakers' sound. Whether this limitation permits or prevents the optimal correction being applied is unclear, but any such restriction is obviously a concern. Plus, there are limits to what can be achieved when, as with the Meridian system, the microphone is placed only at the listening position during the setup process."
...
A superior solution might require a different approach to electronic room correction. Instead of asking the main speakers to apply room correction as well as reproduce the music, we could instead add a third speaker, perhaps more, whose only task is that of applying modal correction. In effect, such a speaker or speakers would provide active modal absorption and offer two principal benefits. First, there is no question of the room-correction signals having an undesirable effect on the main speakers' direct sound. Second, these active absorber(s) can be positioned in one or more room corners, where they can most effectively couple to and so control room modes. If we then also change the setup routine, so that it is able to detect every room mode, we might arrange to kill the room's fundamental width (or length) mode entirely, thereby eliminating the problem of the room's centerline notch."
Διαβάστε ολόκληρο το άρθρο: Stereophile.com
