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Sabato 14 febbraio da Audio Quality partirà un roadshow che porterà il nuovo proiettore DLP 4K trilaser Valerion VisionMaster Max in giro per l'Italia e che toccherà Roma, Genova, Milano, Napoli, Padova e Udinee forse anche Bari e Torino. Maggiori info a questo indirizzo
Consiglio Large Vs Small e LFE/BASS
- Autore discussione ligama
- Data d'inizio
Avenger
New member
Resto del parere che il passa basso sul canale LFE agisce solo ed esclusivamente sul canale LFE, indipendentemente dall'impostazione degli altri diffusori. Impostando tale filtro a 120Hz, non si perde nulla, perchè oltre tale frequenza (di solito già da 80Hz) non c'è nulla nel canale LFE.
luigi.lauro
New member
Confermo che per lo meno negli onkyo non c'è alcun re-indirizzamento dei dati 'tagliati' dall'LPF sull'LFE verso altri diffusori.
Il manuale dice chiaramente che serve per tagliare la fascia altra dell'LFE dove necessario epr ridurre eventuali 'humming' del sub.
Quindi è 'informazione persa' e quindi se il sub 'regge' anche sopra gli 80hz, è deicsmaente più saggio lasciarlo al massimo possibile (sull'onkyo non si può escludere del tutto, ma solo metterlo a 120hz massimo).
Il manuale dice chiaramente che serve per tagliare la fascia altra dell'LFE dove necessario epr ridurre eventuali 'humming' del sub.
Quindi è 'informazione persa' e quindi se il sub 'regge' anche sopra gli 80hz, è deicsmaente più saggio lasciarlo al massimo possibile (sull'onkyo non si può escludere del tutto, ma solo metterlo a 120hz massimo).
peppe69
Active member
allora io vorrei capire il vostro discorso
se taglio il canale lf a 120hz, da li in giu va al sub e da li in su va ai frontali giusto?
se invece lfe lo mettiamo a 80hz tutto quello che va sotto e diretto al sub e quello che va sopra questa frequenza va ai diffusori giusto?
o mi sono perso qualcosa?
se taglio il canale lf a 120hz, da li in giu va al sub e da li in su va ai frontali giusto?
se invece lfe lo mettiamo a 80hz tutto quello che va sotto e diretto al sub e quello che va sopra questa frequenza va ai diffusori giusto?
o mi sono perso qualcosa?
luigi.lauro
New member
Ti sei perso il fatto che la maggior parte degli ampli NON REDIRIGE la parte tagliata dell'LFE ai frontali, ma la taglia e basta.
Tutti gli onkyo fanno così, per dire.
Tutti gli onkyo fanno così, per dire.
luigi.lauro
New member
Aggiungo una nota interessante, presa ad AVForums che spiega perfettamente come funziona e quali sono le implicazioni:
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The LPF of LFE has been discussed at length in the 705/805 threads at AVS. One of the principals at Audyssey tried to get Onkyo not to even give the user the LPF of LFE option because they recognized the confusion it would generate. Of course, they also tried to get Onkyo not to set speakers as full range just because their -3dB point was below 80hz, but that didn't work either.
To add insult to injury, Onkyo defaults the LPF of LFE to 80hz (and includes the THX logo with that choice on the 805 suggesting some official endorsement). While I'vre read that audio mixers *generally* limit the LFE channel to <80hz content, they don't technically have to. While it's not likely to be much, I'd prefer not to lose 1/2 octave of material that *could* be there. If you set the LPF of LFE to less than 120hz, this will simply throw away content above the frequency you select. It's not the same thing as redirected bass, which is what you're dealing with when you set the main-sub crossover frequencies.
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The LPF of LFE has been discussed at length in the 705/805 threads at AVS. One of the principals at Audyssey tried to get Onkyo not to even give the user the LPF of LFE option because they recognized the confusion it would generate. Of course, they also tried to get Onkyo not to set speakers as full range just because their -3dB point was below 80hz, but that didn't work either.
To add insult to injury, Onkyo defaults the LPF of LFE to 80hz (and includes the THX logo with that choice on the 805 suggesting some official endorsement). While I'vre read that audio mixers *generally* limit the LFE channel to <80hz content, they don't technically have to. While it's not likely to be much, I'd prefer not to lose 1/2 octave of material that *could* be there. If you set the LPF of LFE to less than 120hz, this will simply throw away content above the frequency you select. It's not the same thing as redirected bass, which is what you're dealing with when you set the main-sub crossover frequencies.
luigi.lauro
New member
E ancora
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On the 805, the "LPF OF LFE" setting has nothing to do with the crossover points of the other channels (which are set independantly). This setting is basically a brickwall filter for the LFE channel ONLY for systems that are THX certified (i.e. where the subwoofer is not designed to produce significant output above 80Hz since 80Hz crossovers are expected all the way around by design). The Onkyos default to the THX setting of 80Hz for this, and it is not changed during the Audyssey MultEQ XT setup. I'll say again: This does NOT affect redirected bass from the other channels; it is just a low pass filter to truncate the upper end of the LFE channel.
Ideally, you always want to set LPF of LFE to 120Hz unless your subwoofer can't handle material up to 120Hz (and if it can't, you bought a crappy subwoofer). The LFE channel is called the .1 channel because it contains 1/10th of the bandwidth of the other channels (i.e. only up to 120Hz, whereas the other channels contain the full range of 20Hz-20kHz). Now, the THX conceit is that while the LFE channel is filtered at 120Hz anyway, little above 80Hz is placed in there by audio engineers doing the sound mix to prevent the subwoofer from being directional. This conceit, however, forgets one major thing: the harmonics of a sound create the "tone" we perceive, especially where bass is concerned.
Now here's the thing: 99% of people will not hear a difference between an 80Hz setting for this and the 120Hz setting, because they won't know what to listen for. A good example of a disc where this tonality comes into play is the opening Sauron scene of LOTR: The Fellowship Of The Ring. When Sauron is killed, there's a sweeping bass tone that is primarily in the LFE channel (though directional bass is in the main channels as well). If you set the LPF of LFE to 80Hz, you should notice a subtle but noticeable difference in the tone that this sweep has as opposed to 120Hz. Will it greatly affect your enjoyment? Probably not. As I said - most people won't notice. But from a strictly technical standpoint, you should set this to 120Hz to ensure that your subwoofer is properly reproducing the full range of the LFE channel.
As far as the way Polk says to wire the RM6880, the only reason I can think of that they would do this is if they're using a gradual high-pass of the L&R satellites to maintain directionality of bass, as opposed to the usual steeper slope of the digital crossovers in a receiver. This may also be because most consumer AVRs use a 80Hz crossover and only offer "LARGE" (i.e. full band) or "SMALL" (i.e. 80Hz) settings. Given the small size of the satellites in the RM6880 package, you certainly wouldn't want to send significant bass down to 80Hz to them.
If I'm being honest, I disagree with their wiring diagram when paired with this particular receiver (or any that allows independantly adjustable crossovers, especially where they're gauged during the auto-setup as Audyssey does). Audyssey's MultEQ XT on the Onkyos does a pretty good job of detecting any -3dB point so long as it is above 80Hz. The Onkyos set any speaker that extends down to 80Hz to FULL BAND, even if they shouldn't. Audyssey pushed for Onkyo to use 40Hz for this threshhold, but that was ultimately Onkyo's call. One big reason that I disagree with their wiring diagram is that they're running the L&R main channels through an active crossover network, which can introduce group delay (which alters the optimal speaker distance/delay settings). Ideally, you would want the receiver to handle these crossover points at a digital level so that there's no group delay involved (which is one of the advantages of AVRs with per-channel independent crossovers). If you're running the mains the way Polk recommends, however, there's no phase variance between the mains and subwoofer since bass is being handled through the same crossover network.
Having said that, don't go out of your way to re-wire it now. While the crossover network in the RM6880 might introduce delay, another thing that Audyssey does is measure the acoustic distance as opposed to physical distance, taking into account any delay introduced by the system. This is why, after running MultEQ XT's auto-setup, the measured speaker distances may differ slightly from the actual physical distance you measure in the room. In the case of systems where the subwoofer is wired seperately from the mains, you may even notice a vastly different setting for the subwoofer than its physical distance, since MultEQ XT is attempting to align the phase of the subwoofer and main channels. Keeping the subwoofer in phase with the other speakers is complicated by placement, especially if your sub is placed within 3-5" of any wall (which can cause phase reversal or reverberation that causes the wall surface to act as a passive radiator, throwing off the time the first impulse of sound arrives at your main listening position).
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On the 805, the "LPF OF LFE" setting has nothing to do with the crossover points of the other channels (which are set independantly). This setting is basically a brickwall filter for the LFE channel ONLY for systems that are THX certified (i.e. where the subwoofer is not designed to produce significant output above 80Hz since 80Hz crossovers are expected all the way around by design). The Onkyos default to the THX setting of 80Hz for this, and it is not changed during the Audyssey MultEQ XT setup. I'll say again: This does NOT affect redirected bass from the other channels; it is just a low pass filter to truncate the upper end of the LFE channel.
Ideally, you always want to set LPF of LFE to 120Hz unless your subwoofer can't handle material up to 120Hz (and if it can't, you bought a crappy subwoofer). The LFE channel is called the .1 channel because it contains 1/10th of the bandwidth of the other channels (i.e. only up to 120Hz, whereas the other channels contain the full range of 20Hz-20kHz). Now, the THX conceit is that while the LFE channel is filtered at 120Hz anyway, little above 80Hz is placed in there by audio engineers doing the sound mix to prevent the subwoofer from being directional. This conceit, however, forgets one major thing: the harmonics of a sound create the "tone" we perceive, especially where bass is concerned.
Now here's the thing: 99% of people will not hear a difference between an 80Hz setting for this and the 120Hz setting, because they won't know what to listen for. A good example of a disc where this tonality comes into play is the opening Sauron scene of LOTR: The Fellowship Of The Ring. When Sauron is killed, there's a sweeping bass tone that is primarily in the LFE channel (though directional bass is in the main channels as well). If you set the LPF of LFE to 80Hz, you should notice a subtle but noticeable difference in the tone that this sweep has as opposed to 120Hz. Will it greatly affect your enjoyment? Probably not. As I said - most people won't notice. But from a strictly technical standpoint, you should set this to 120Hz to ensure that your subwoofer is properly reproducing the full range of the LFE channel.
As far as the way Polk says to wire the RM6880, the only reason I can think of that they would do this is if they're using a gradual high-pass of the L&R satellites to maintain directionality of bass, as opposed to the usual steeper slope of the digital crossovers in a receiver. This may also be because most consumer AVRs use a 80Hz crossover and only offer "LARGE" (i.e. full band) or "SMALL" (i.e. 80Hz) settings. Given the small size of the satellites in the RM6880 package, you certainly wouldn't want to send significant bass down to 80Hz to them.
If I'm being honest, I disagree with their wiring diagram when paired with this particular receiver (or any that allows independantly adjustable crossovers, especially where they're gauged during the auto-setup as Audyssey does). Audyssey's MultEQ XT on the Onkyos does a pretty good job of detecting any -3dB point so long as it is above 80Hz. The Onkyos set any speaker that extends down to 80Hz to FULL BAND, even if they shouldn't. Audyssey pushed for Onkyo to use 40Hz for this threshhold, but that was ultimately Onkyo's call. One big reason that I disagree with their wiring diagram is that they're running the L&R main channels through an active crossover network, which can introduce group delay (which alters the optimal speaker distance/delay settings). Ideally, you would want the receiver to handle these crossover points at a digital level so that there's no group delay involved (which is one of the advantages of AVRs with per-channel independent crossovers). If you're running the mains the way Polk recommends, however, there's no phase variance between the mains and subwoofer since bass is being handled through the same crossover network.
Having said that, don't go out of your way to re-wire it now. While the crossover network in the RM6880 might introduce delay, another thing that Audyssey does is measure the acoustic distance as opposed to physical distance, taking into account any delay introduced by the system. This is why, after running MultEQ XT's auto-setup, the measured speaker distances may differ slightly from the actual physical distance you measure in the room. In the case of systems where the subwoofer is wired seperately from the mains, you may even notice a vastly different setting for the subwoofer than its physical distance, since MultEQ XT is attempting to align the phase of the subwoofer and main channels. Keeping the subwoofer in phase with the other speakers is complicated by placement, especially if your sub is placed within 3-5" of any wall (which can cause phase reversal or reverberation that causes the wall surface to act as a passive radiator, throwing off the time the first impulse of sound arrives at your main listening position).
ULTRAVIOLET80
New member
luigi.lauro ha detto:
Quindi, se ho ben capito, il sub, in questo caso, dovrà preoccuparsi di "gestire" anche il lavoro dei frontali (per quanto riguarda le frequenze al di sotto dei 100hz) più ovviamente le "propria" traccia (la .1)
ULTRAVIOLET80
New member
E lo stesso dovrebbe accadere settando anche gli altri diffusori (centrale e surround) ad un determinato livello..
Quindi, la soluzione più "logica" dovrebbe essere quella di settare il sub a 120 hz (per non perdere nessuna informazione) e gli altri diffusori ad un livello "consono" alle propria risposta in frequenza. (tenendo cmq presente che i "dati di targa" dichiarati dai produttori sono piuttosto ottimistici)
Quindi, la soluzione più "logica" dovrebbe essere quella di settare il sub a 120 hz (per non perdere nessuna informazione) e gli altri diffusori ad un livello "consono" alle propria risposta in frequenza. (tenendo cmq presente che i "dati di targa" dichiarati dai produttori sono piuttosto ottimistici)
luigi.lauro
New member
Esattamente... considerate anche che l'Audyssey non fa la cosa giusta: mette in full uno speaker quando scende sotto gli 80hz... mentre invece dovrebbe vedere la risposta e metterlo full SE E SOLO SE riesce a coprire a -3db o meglio tutto il range dei bassi o per lo meno fino a 30-40hz (le frequenze più basse di solito vengono messe nella LFE e non nei frontali in un film)...
L'ideale forse è guardare le specifiche delle casse, prenderle cum grano salis, e settare di conseguenza i crossover.
Quindi se una cassa dice tipo 51hz a -3db, io la metterei a 50/60hz, non di meno di sicuro...
Alcuni non gradiscono il sub in ascolto stereofonico, ma la verità è che sono pochissimi i frontali che riescono a scendere con naturalezza e precisione molto in basso (ovvero 20-30hz), e quasi sempre se si cerca davvero l'alta fedeltà, conviene affiancarli ad un sub, specialmente se questo si presta ad un ascolto musicale (sub in cassa chiusa preciso e veloce, e ben equalizzato)
L'ideale forse è guardare le specifiche delle casse, prenderle cum grano salis, e settare di conseguenza i crossover.
Quindi se una cassa dice tipo 51hz a -3db, io la metterei a 50/60hz, non di meno di sicuro...
Alcuni non gradiscono il sub in ascolto stereofonico, ma la verità è che sono pochissimi i frontali che riescono a scendere con naturalezza e precisione molto in basso (ovvero 20-30hz), e quasi sempre se si cerca davvero l'alta fedeltà, conviene affiancarli ad un sub, specialmente se questo si presta ad un ascolto musicale (sub in cassa chiusa preciso e veloce, e ben equalizzato)
luigi.lauro
New member
Giustissimo avenger, ma audyssey setta full anche diffusori che arrancano gia a 60-70hz... e sono convinto che ci sia segnale nei canali L/R su quel range...
Se si hanno diffusori da scaffale o comunque con piccoli woofer e/o litraggio, conviene metterli a 80hz o giu di li, e redirigere sul sub.
Per l'ascolto musicale è diverso: a volte meglio i due frontali in full e basta, a volte meglio i due frontali tagliati 'giusti' e aiutati dal sub nella fascia più bassa, soprattutto per i generi che hanno un basso ben presente (rock, pop, etc...). Dipende.
Se si hanno diffusori da scaffale o comunque con piccoli woofer e/o litraggio, conviene metterli a 80hz o giu di li, e redirigere sul sub.
Per l'ascolto musicale è diverso: a volte meglio i due frontali in full e basta, a volte meglio i due frontali tagliati 'giusti' e aiutati dal sub nella fascia più bassa, soprattutto per i generi che hanno un basso ben presente (rock, pop, etc...). Dipende.