help me understand x-over hz?

[liquidice]

so I re-ran my audyssey calibration last night, and got thinking about the settings as them came back after all 8 positions where recorded. It set my mains both to 150 hz, and my rear surround to 150 hz, but put my center channel (exact same speaker as my mains) to 90 hz. Now, the sub of course is at 80 hz as most usually are. Can someone put into simple terms what this all means? From what I know, the sub should only be putting out frequencies below 80 hz, but if the mains for instance are set at 150 hz, where does that freq between 150 and 80 go?...and why is my center channel at 90?...for better quality dialogue? Like I said, I just need an explanation to help me better understand. Thanks.

[ludawg23]

I'll take a stab.

150 as a x-over point is quite high. Your sub is designed for low frequency effects...150hz is not low.

I would personally just set everything to 80hz and turn your subwoofer x-over to max and let your receiver do the bass management. With an independent subwoofer, this will alleviate the stress put on your fronts and rears to produce LFE sound and re-directs it to your sub to take care of.

[jomari]

the 80-150 frequency should still be heading towards your subwoofer.

im assuming we are referring to your sub setting of 80Hz is on your sub correct? (of course, receivers wouldnt have that option now does it) with your crossover settings on the sub at 80hz, its leaving a 'gap' where you should be receiving the other frequencies. thats why i prefer to bypass the speaker crossover settings, and let the subwoofer do it for you.

if you check your manual, you can see the frequency responses for your fronts, your rear and your center speaker. at this point you should be able to determine your crossover settings.

Audyssey and their corresponding programs, are used primarily for room equalization, with it trying to assist you with the speaker setup.

here

[liquidice]

actually my sub has no setting directly on it for x-over freq. The settings for all the frequencies are on the receiver. I do have to say, the sound is truely amazing, so I'm not complaining that these settings sound bad, I'm just trying to figure out "why" did audyssey chose these settings. Interesting replies so far...

[Audiophile_At_Birth]

Originally Posted by liquidice

actually my sub has no setting directly on it for x-over freq. The settings for all the frequencies are on the receiver. I do have to say, the sound is truely amazing, so I'm not complaining that these settings sound bad, I'm just trying to figure out "why" did audyssey chose these settings. Interesting replies so far...

Audyssey isn't perfect, but it's close. It all has to do with room acoustics and how good your speakers are. If you have speakers that lack in the low end, Audyssey will try to compensate for this by setting a high crossover. Just curiousity, what kind of speakers are you running?

[jomari]

lets get your specs right.

kindly indicate what you have for your current system. from the gallery it shows you have a denon 988, but i cant see your specs for your subs.

what the reciever does is that it 'filters' out a good portion of certain frequencies lower than the crossover setting designated IN the reciever.

for example, if all speakers are set to 80hz, then anything lower than 80hz goes into the subwoofer. in your case, since you have multiple crossover points, they would go into the subwoofer. you've mentioned your crossover is set at 80hz, how? on ths subwoofer? on the receiver? if its ont he receiver, then you are missing out on any frequencies in between 80-150 causing a double crossover so to speak.

[aramis109]

Your LPF of LFE should be high enough to encompass your crossover point. So, if you have a crossover point of 150hz (which is probably wrong, but we can get to that in a moment) you want the LPF of LFE to be 150hz. Otherwise, anything from 80hz - 150hz will be lost- it'll be sent to your sub and your sub will discard it.

More than likely though, your crossover points are wrong. While jomari's suggestion to get the specs is definitely where you want to look, a general rule of thumb is satellites at 120hz, bookshelf at 80hz, and towers at 80hz or below. THX recommends 80hz all the way around, which is of course up to you.

I have my system set at 80hz all the way around and the LPF of LFE at 120hz. This way I'm not missing anything while making sure I don't have any "unnatural" audio coming from the sub.

[Pelican170]

Originally Posted by aramis109

Your LPF of LFE should be high enough to encompass your crossover point. So, if you have a crossover point of 150hz (which is probably wrong, but we can get to that in a moment) you want the LPF of LFE to be 150hz. Otherwise, anything from 80hz - 150hz will be lost- it'll be sent to your sub and your sub will discard it.

More than likely though, your crossover points are wrong. While jomari's suggestion to get the specs is definitely where you want to look, a general rule of thumb is satellites at 120hz, bookshelf at 80hz, and towers at 80hz or below. THX recommends 80hz all the way around, which is of course up to you.

I have my system set at 80hz all the way around and the LPF of LFE at 120hz. This way I'm not missing anything while making sure I don't have any "unnatural" audio coming from the sub.

I disagree. I find that most of the time Audessy is correcting room imperfections, such as furniture placement, windows..... and for the most accurate sound, you should go by that audessey setting unless you can do a SPL meter test. People often forget about how the room and certain factors can affect the sound. The specs of speakers are done is perfect rooms when tested, and most living rooms and such are not like this...

[jomari]

audyssey is basically a guide towards helping you maximize your speakers interaction with the room. its more about room equalization, instead of speaker 'settings'.

as aramis mentioned, i do concur with it. but at times, ive experimented with bypassing the subwoofers crossover settings, letting the reciever do the job instead.

both of you are correct,

with aramis pointing out the speaker settings, while pelican is referring to audysseys setup used as a tool to equalize the room. both interactive, but different from one another. we are working on two aspects here, one would be how to maximize his current speaker setup,while having the audyssey program guide him/her towards room relations.

[aramis109]

Originally Posted by Pelican170

I disagree. I find that most of the time Audessy is correcting room imperfections, such as furniture placement, windows..... and for the most accurate sound, you should go by that audessey setting unless you can do a SPL meter test. People often forget about how the room and certain factors can affect the sound. The specs of speakers are done is perfect rooms when tested, and most living rooms and such are not like this...

I just can't imagine a room correction that requires such a high crossover point. Hence my point in saying that was probably wrong. Audyssey is good stuff though- I use it in the place of an SPL meter. Also, jomari pretty much hit it on the head in what I was trying to get across.

[liquidice]

here are speakers specs:

Sub: 120 watts / 20-200kwz

Center and mains: JBL Control-1
Frequency Range: 70 Hz - 20 kHz (-10dB)
Crossover Frequency: 6 kHz

...and once again, the only control on the sub itself is an output/volume knob, there is no control of crossover or phase.

[jomari]

i think you've asked that question before if im not mistaken.

so...

receiver settings
Fronts LCR crossover - 80hz
Rears - 150Hz

MOST frequencies found under the mentioned crossover points will head towards your subwoofer. with an SPL meter, try to calibrate your subwoofers gain/volume to a respectable value, without adding too much nor too little to your system.

[Cisco in HD]

Personally, I just use Audessy for the speaker distances. I've rerun Audessy several times in my room with how it directed me to do and well, it sounded wrong.

If you have/can borrow an SPL meter use it. It's a well spent 2 or so mins to get the levels right.

I use 80hz for my center, 80 for my tower fronts, 110 for my surrounds, and 80 for my sub.
Since I don't have settings on the back of my sub I put the sub level @ +1 on the receiver and then used the vol on my sub to adjust when using the SPL meter.

Just my .02

[liquidice]

Originally Posted by jomari

i think you've asked that question before if im not mistaken.

yeah, I did, but that was before getting this new receiver and messing around with the audyssey calibration. I just ran my AVIA disc, and all-though the receiver set the L/R mains to 150 hz, on the bass sweep test, it seems that you can hear the test tone on the mains down to almost 80 hz, which would be correct based on the speaker specs, but the sub also kicks in around the 150 hz as well. Doing an audio test of a new U2 song, the bass sounds better with the audyssey settings, and not as good when I set the mains to 80hz.

[jomari]

theres a number of variables here in play, the source, the media, the room etc.

when you set the fronts to 80hz, its a suggestion, we try to see if we can push the speakers to its capabilities, and maximize what we can from them.

what counts is what matters to you. how it sounds. if it sounds better using 150hz, go ahead, if it goes with 80hz, you can choose that as you wish.

we also suggest to try to 'audition' the setup for a couple of days, then see if it works out for you. if ever, see what difference it makes.

good luck.

[Pelican170]

Originally Posted by aramis109

I just can't imagine a room correction that requires such a high crossover point. Hence my point in saying that was probably wrong. Audyssey is good stuff though- I use it in the place of an SPL meter. Also, jomari pretty much hit it on the head in what I was trying to get across.

Jomari makes sense. But let me ask you a question. You hear alot of people saying "just put the speaker setting to small" now, when you do that, is that changing a crossover for the speakers? i honestly dont know, my receiver doesnt have that option, but i always assumed that it would make it so the sub was outputting most of the bass, kind of how it would be if you put the crossover to 150 or 200... make sense?


P.S. I do agree with your above mention of not wanting unnatural sound coming from the sub. I noticed this on my system when i first set it up and took a little while to tweak out...

[aramis109]

Originally Posted by Pelican170

Jomari makes sense. But let me ask you a question. You hear alot of people saying "just put the speaker setting to small" now, when you do that, is that changing a crossover for the speakers? i honestly dont know, my receiver doesnt have that option, but i always assumed that it would make it so the sub was outputting most of the bass, kind of how it would be if you put the crossover to 150 or 200... make sense?


P.S. I do agree with your above mention of not wanting unnatural sound coming from the sub. I noticed this on my system when i first set it up and took a little while to tweak out...

Putting it to small takes it off full band and allows you to set a crossover point. When they're on "large" it runs them full band.

Also to Cisco in HD, what do you think happens when your surrounds are set at 110 and your sub's LPF is set at 80? You get an audio hole- the surrounds send anything 110hz and below to the sub. The sub discards anything 80hz and up- thus, 80hz to 110hz audio is lost.

[Pelican170]

[QUOTE=aramis109;1667445]Putting it to small takes it off full band and allows you to set a crossover point. When they're on "large" it runs them full band. QUOTE]


Gotcha, didnt realize when they are on large it sets them to Full Band...

[jomari]

Originally Posted by aramis109

Also to Cisco in HD, what do you think happens when your surrounds are set at 110 and your sub's LPF is set at 80? You get an audio hole- the surrounds send anything 110hz and below to the sub. The sub discards anything 80hz and up- thus, 80hz to 110hz audio is lost.

correct. as unnatural as it sounds, we refer to it as double crossovering a system, where you filter too much of the subwoofer, leaving you at a loss.

the audio frequencies in between 80hz and 110 is 'supposed' to send the signal still to the subwoofer. this also happens when you add on a second sub in the picture.

in theory, the best setup is to connect the subwoofer via an LFE connection,letting the receiver do the crossover, and it bypasses the internal crossover of the subwoofer.

[liquidice]

all in all, I'm going to leave it as-is. When doing the the ASIA test, my mains seem to rattle just abit, and I find this very annoying. Of course this is a "test-tone", and probably would not hear anything similar while watching a movie. Just to be sure, I just watched the opening segment of "Master & Commander", and everything sounded top-notch. When I get around to getting full range speakers, I'm sure the crossover will be tweaked quite differently. The JBL's are excellent for high to midrange, so the sub doing extra work is fine by me. Everyone's advice has been superb.