overlapping crossover point

SlowcarIX

thinking of lowering the xover point on the LCR...

L/C/R - high pass @60Hz
Sub - low pass @80Hz

this is on LSi9 and epik conquest. is there a disadvantage to this after calibration with audyssey?

Early B.

There's only one way to find out...

Experiment with several options and see what you like. Have fun.

kuntasensei

Are you talking about the low pass on the subwoofer itself or your Onkyo's LPF of LFE setting? If it's the LPF of LFE setting, turn it up to 120Hz so the full LFE channel reaches the subwoofer. This setting does not affect bass redirected from the other channels at all, so you're not overlapping crossovers - it's just a low pass filter of the LFE channel to maintain legacy THX spec, and isn't something you need to use (it defaults to 80Hz - Audyssey doesn't adjust this or do any detection for it).

If you're talking about the subwoofer itself, turn its crossover all the way to its maximum and let the pre-pro handle the bass management. The crossover circuitry on the sub can induce delay that will throw off Audyssey's distance detections. The only time you'd need to use the crossover on the sub itself is a) if you're getting power-induced hum or b) if you're routing speaker level connections through the subwoofer itself, bypassing the receiver's bass management. A caveat: If your sub's crossover is currently not at its max and you change it, you might need to re-run Audyssey so it can ensure proper distance/delay to keep your sub in phase with the other channels.

As far as changing the crossovers of the speakers themselves: Audyssey on the Onkyos usually detects any speaker that can go below 80Hz as "full range". Accordingly, Audyssey equalizes the entire range of the speaker... so if you then set that channel to a higher crossover point, no harm. Audyssey just disregards the equalization below the new crossover point. If, however, a speaker detected as 100Hz and you set it to 80, that's a problem because Audyssey only equalizes down to the point it initially detected.

The usual guideline for proper system crossovers is to take the speaker's lower -3dB point and multiply times 1.5. This gives you a half-octave for the transition from speaker to sub. You might, however, be able to adjust slightly lower than this with good results because in-room response is typically lower than the anechoic response given in the specs. For instance, your LSi9s have a -3dB point of 50Hz, making 75Hz the ideal setting for them. Since your options are either 70 or 80, you could get away with 70. Given the slope of the crossover, you MIGHT lose a little audio by going as low as 60Hz, since the speaker's natural rolloff will start to overlap with the transition of the crossover. However, it might work just fine, depending on in-room response, or at least the slight dip you get from the crossover cascading with the speaker's rolloff may not be noticeable. Likewise, your LSiC has a 52Hz -3dB point, so 1.5x = 78Hz. 80Hz would be a safe crossover point, but 70 should work fairly well. In fact, I've found that putting the center channel lower than 80 usually helps with bassy voices.

SlowcarIX

Early B. wrote: »

There's only one way to find out...

Experiment with several options and see what you like. Have fun.

was trying to be lazy

SlowcarIX

kuntasensei wrote: »

Are you talking about the low pass on the subwoofer itself or your Onkyo's LPF of LFE setting? If it's the LPF of LFE setting, turn it up to 120Hz so the full LFE channel reaches the subwoofer. This setting does not affect bass redirected from the other channels at all, so you're not overlapping crossovers - it's just a low pass filter of the LFE channel to maintain legacy THX spec, and isn't something you need to use (it defaults to 80Hz - Audyssey doesn't adjust this or do any detection for it).

If you're talking about the subwoofer itself, turn its crossover all the way to its maximum and let the pre-pro handle the bass management. The crossover circuitry on the sub can induce delay that will throw off Audyssey's distance detections. The only time you'd need to use the crossover on the sub itself is a) if you're getting power-induced hum or b) if you're routing speaker level connections through the subwoofer itself, bypassing the receiver's bass management. A caveat: If your sub's crossover is currently not at its max and you change it, you might need to re-run Audyssey so it can ensure proper distance/delay to keep your sub in phase with the other channels.

As far as changing the crossovers of the speakers themselves: Audyssey on the Onkyos usually detects any speaker that can go below 80Hz as "full range". Accordingly, Audyssey equalizes the entire range of the speaker... so if you then set that channel to a higher crossover point, no harm. Audyssey just disregards the equalization below the new crossover point. If, however, a speaker detected as 100Hz and you set it to 80, that's a problem because Audyssey only equalizes down to the point it initially detected.

The usual guideline for proper system crossovers is to take the speaker's lower -3dB point and multiply times 1.5. This gives you a half-octave for the transition from speaker to sub. You might, however, be able to adjust slightly lower than this with good results because in-room response is typically lower than the anechoic response given in the specs. For instance, your LSi9s have a -3dB point of 50Hz, making 75Hz the ideal setting for them. Since your options are either 70 or 80, you could get away with 70. Given the slope of the crossover, you MIGHT lose a little audio by going as low as 60Hz, since the speaker's natural rolloff will start to overlap with the transition of the crossover. However, it might work just fine, depending on in-room response, or at least the slight dip you get from the crossover cascading with the speaker's rolloff may not be noticeable. Likewise, your LSiC has a 52Hz -3dB point, so 1.5x = 78Hz. 80Hz would be a safe crossover point, but 70 should work fairly well. In fact, I've found that putting the center channel lower than 80 usually helps with bassy voices.

the present setup -
sub:
volume = 50%
switched to LFE on selector

on the avp:
sub - 80Hz
L/C/R/SL-R/SBL-R - all set to 80Hz

are there frequency higher than 80Hz recorded into a movies LFE track?

kuntasensei

There's not a lot above 80Hz in the LFE channel, but there can be harmonics that give the content there its tone. You'll see a lot of people advocate leaving this at 80Hz. However, my opinion is that there's no sense in throwing out what the audio designers meant you to hear/feel, nor is there any sense in going against Dolby/DTS specs just for the THX conceit of limiting the LFE channel to sub-80Hz material.

Will you hear much of a difference either way? Probably not unless someone pointed out what to listen for.

SlowcarIX

i kept the low pass @80Hz because this is a combo 2ch/HT setup and any higher, the bass will be directional? did the calibration at 2am and did not get chance to try it out...will see how it sounds after work

kuntasensei

Put the LPF of LFE at 120Hz. Trust me. It doesn't make the sub any more directional; it just lets the harmonics above 80Hz in the LFE channel be played as they were meant to.

If you don't believe me, here's what Chris Kyriakakis of Audyssey said in the Audyssey thread at AVS: "The LFE lowpass should be set to 120 Hz after calibration is complete. It should never be any other number. Audyssey does not control that, so it has to be set manually."

The LPF of LFE has NO effect on redirected bass... and when playing 2 channel, the filter isn't even in use (because it only affects the LFE channel of digital soundtracks - NOT redirected bass from the other speakers).

SlowcarIX

i compared 2 combinations:

1 - Speakers high pass @80Hz and sub low pass on avp @120Hz and
2 - speakers hp@50Hz and sub@120Hz

1 sounds better - sounds cleaner
2 sounds "cluttered", was actually giving me a headache!

thanks for the advice!

ward91

frikin cambridge amps dont cross the bass over they just "duplicate" and "re-direct" (double bass here? ) the added bass to the sub. kinda sucks if you own "small" speakers.

Eric W

Just keep in mind you should play with the phase setting on your sub for smoothest response if you have that much of an overlap.

kuntasensei

I agree with Eric, but only if you're not using Audyssey. Changing the subwoofer phase post-Audyssey will alter the EQ solution it came up with. If you want to verify phase, turn Audyssey's EQ off, verify phase with test tones, then re-run Audyssey so it can recalculate the necessary corrections. Keep in mind that changing the phase on the sub can affect the subwoofer distance calculation, since it measures acoustic distance (and since the distance/delay effectively acts as a de facto phase control).