I'm considering the idea of desiging all speakers in a surround system to have F3 down to at least 40 Hz in all speakers. I'd like some comments on this approach, especially from those who have tried it with experiences to share.
* does it give smoother in-room bass response?
* is it worth bass from the centre, main and rear channels?
* should you set your speakers to "small" even though they have good bass response in order to get more dynamic range?
* does it give smoother in-room bass response?
* is it worth bass from the centre, main and rear channels?
* should you set your speakers to "small" even though they have good bass response in order to get more dynamic range?
Hi Paul,
I think you have a good plan there as long as you can set your av processors x/o to match the 40Hz roll off.
I believe the processors amps usually x/o at 12Db hi pass around 80Hz to match a sealed roll off, creating a 24Db hi-pass at 80.
The sub outputs are x/o'd at 24Db to match.
Personally I'm heading for seperate subs for the surrounds, using the full range outs from my processor, with full range mains and my main subs just for LFE.
Cheers
Rob
I think you have a good plan there as long as you can set your av processors x/o to match the 40Hz roll off.
I believe the processors amps usually x/o at 12Db hi pass around 80Hz to match a sealed roll off, creating a 24Db hi-pass at 80.
The sub outputs are x/o'd at 24Db to match.
Personally I'm heading for seperate subs for the surrounds, using the full range outs from my processor, with full range mains and my main subs just for LFE.
Cheers
Rob
This is not very quantitative, but I sit and watch the FFT of the various channels on occasion, and the center/surround often seem band limited in the original mix. i.e. there is generally not very much power below 100HZ or above 10kHz. This has led me to believe that the capabilities of the surround channels need not be that great...but I wouldn't argue that adding that extra octave won't improve the sound...just that the difference might be very small. It is also going to vary a lot from recording to recording, I assume.
I AM talking about the mix on the disc; my processor is setup to go full range and I've measured the output to confirm there isn't any rolloff.
I AM talking about the mix on the disc; my processor is setup to go full range and I've measured the output to confirm there isn't any rolloff.
Rob,
Doesn't it concern you that there may not be very much signal going to the subs in the surround channels? What if they get bored and just sit there gathering dust?
I'm inclined to agree with using the bass from the main speakers, but subs for surround channels? hmmmmmm
How many subs? 3?
Tiroth,
What kind of movies did you look at? How much of a sample of movies are we talking about here?
The surround speakers in a comercial cinema don't look like they could handle any bass at all for a large space. Does this suggest that bass just isn't mixed to surround channels, or are DVDs mixed differently than the sound track used in cinemas?
Doesn't it concern you that there may not be very much signal going to the subs in the surround channels? What if they get bored and just sit there gathering dust?
I'm inclined to agree with using the bass from the main speakers, but subs for surround channels? hmmmmmm
How many subs? 3?
Tiroth,
What kind of movies did you look at? How much of a sample of movies are we talking about here?
The surround speakers in a comercial cinema don't look like they could handle any bass at all for a large space. Does this suggest that bass just isn't mixed to surround channels, or are DVDs mixed differently than the sound track used in cinemas?
I've been wondering about this as well. I've been thinking of building a small tower similar to the Creative Sound Spires, but my only concern is how much bass response I need.
The speakers I was going to use I can get to about an F3 or maybe 110Hz ...
I know my dad's Sony HT setup doesn't have much bass response in any of the channels (one of those satellite setups), so I don't think it'll be that big an issue.
The speakers I was going to use I can get to about an F3 or maybe 110Hz ...
I know my dad's Sony HT setup doesn't have much bass response in any of the channels (one of those satellite setups), so I don't think it'll be that big an issue.
Toonz,
What I'm concerned here is not so much a "problem" but rather more of a preference. Can a small (or perhaps not so small) but worthwhile improvement be made with bass through all channels ...
In your case it's just not possible or desirable as it would push those drivers too hard. (I assume you are using small TB's or similar). I wouldn't be too concerned. If you get a sealed 2nd order rolloff at 110 Hz then I'd say that will be fine.
What I'm concerned here is not so much a "problem" but rather more of a preference. Can a small (or perhaps not so small) but worthwhile improvement be made with bass through all channels ...
In your case it's just not possible or desirable as it would push those drivers too hard. (I assume you are using small TB's or similar). I wouldn't be too concerned. If you get a sealed 2nd order rolloff at 110 Hz then I'd say that will be fine.
RobWells said:
in some instances i do believe there is bass information in the surroud channels yet for most applications i think if the surround channel roll off is gradual (read as sealed) one can get by with a F3 of 100hz. It all depends on your application like 5.1 audio.
if your rear sub is active then you might have to run a rather long RCA cable to the sub. this can be a problem.
navin said:
Yes, I can see the value of bass info in the surrounds in 5.1 audio, although I don't think a subwoofer is warranted. I do expect there will be quite a number who will want subwoofers for surround channels for this application.
Why would long RCA line level cable be a problem? (I thought this was a problem, until a recent discussion regarding interference, now I'm not so sure).
paulspencer said:
Ahh.. I certainly think an improvement would be made. I'm sure in some movies, espacially war type ones or ones with explosions it would be useful.
Eg I was watching Tears of the Sun on the weekend, and I'm sure in the scenes with explosions happening all around you there'd be some spots where there should be some bass in the rear channels.
Yeah, not TB's but similar 4" drivers, I want some nice small rears as I don't have much space!
Could always run a sub off the speaker level using the rear speakers. HT receiver rear speakers set to large > rear LR speaker leads to sub > speaker leads from sub output to LR rears. Set the xo on the sub to suit the rears.
Not easy to test the levels as how do you get tones or music to play through these except by swapping LR front to the LR rears for the test?
I'm going to build a sub to try this out soon but coming off the centre rear channel (wires easier to get to) which is mostly matrixed LR anyway.
If you run from the LFE output on the receiver, don't you get all the bass that has been redirected from other speakers set to small? If placed with the rears, might get confusing... dunno. That's why I thought speaker level would be better as uses only the bass meant for LR rear.
Not easy to test the levels as how do you get tones or music to play through these except by swapping LR front to the LR rears for the test?
I'm going to build a sub to try this out soon but coming off the centre rear channel (wires easier to get to) which is mostly matrixed LR anyway.
If you run from the LFE output on the receiver, don't you get all the bass that has been redirected from other speakers set to small? If placed with the rears, might get confusing... dunno. That's why I thought speaker level would be better as uses only the bass meant for LR rear.
Rabbitz,
The LFE channel is a separate channel, it is not "redirected" as such. It may or may not be the same as the bass in the other channels. If you set the receiver to "small" then a highpass filter reduces the bass. However, if set to large, each track will contain bass, and to some extent this will be different to the LFE channel.
If you want to add a subwoofer to surround speakers, you can either use a line level input from pre-outs if you have them, or use speaker level as you said. The signal is different to the LFE channel, and also there is no bass management from the receiver.
The main issue here as I see it is whether or not there is sufficient bass in the surround channels to make this worthwhile. I suspect that it is worth using the "large" speaker setting, however, I don't think there is going to be enough bass in the surround channels to make a subwoofer worthwhile.
The LFE channel is a separate channel, it is not "redirected" as such. It may or may not be the same as the bass in the other channels. If you set the receiver to "small" then a highpass filter reduces the bass. However, if set to large, each track will contain bass, and to some extent this will be different to the LFE channel.
If you want to add a subwoofer to surround speakers, you can either use a line level input from pre-outs if you have them, or use speaker level as you said. The signal is different to the LFE channel, and also there is no bass management from the receiver.
The main issue here as I see it is whether or not there is sufficient bass in the surround channels to make this worthwhile. I suspect that it is worth using the "large" speaker setting, however, I don't think there is going to be enough bass in the surround channels to make a subwoofer worthwhile.
Assuming there's been no changes in recent years, the surrounds are mixed on what's called an 'x' curve, and there's more than one depending on the mixing room's size and the whim of the eng./producer/client/whoever. The original standard is flat from 63-2kHz, with both ends rolling off at 3dB/octave, so 20Hz is -5dB and 20kHz is -10dB, but according to Dolby, some mix the bottom flat to 20Hz and AFAIK there's nothing on the DVD to warn you, so caveat emptor. The modified curve is flat to 2kHz, but rolls off at 1.5dB/octave (-5dB/20kHz), though some prefer to keep it flat to 4kHz, then roll it off at 3dB/octave (-7dB/20kHz).
If the surrounds are set to small, then everything below 100Hz is sent to the L/R mains, and of course if they're set to small, then all the channel's LF goes to the LFE.
Also, some mix the surrounds at 79dB Vs 85dB to improve dialog intelligibility in a home's typically higher ambient noise, so on movies where this is a problem try setting the surround's reference lower.
Nothing like having multiple 'standards', eh?
HTH,
GM
If the surrounds are set to small, then everything below 100Hz is sent to the L/R mains, and of course if they're set to small, then all the channel's LF goes to the LFE.
Also, some mix the surrounds at 79dB Vs 85dB to improve dialog intelligibility in a home's typically higher ambient noise, so on movies where this is a problem try setting the surround's reference lower.
Nothing like having multiple 'standards', eh?
HTH,
GM
paulspencer said:
Know that..... I wasn't directly referring to the discrete LFE but what I was trying to say and got tongue tied on the keyboard (the brain and typing don't operate at the same speed....... at this hour the typing is quicker than the brain), is if the speaker is set to small the bass below 90Hz (or whatever the filter is set to on the amp) is redirected to the speakers that are to handle the LFE as selected on the bass management such as Sub or Mains or Sub + Mains. So you end up with the discrete LFE + redirected bass from speakers set to small.
So it is possible to have bass redirected from the centre or mains in the LFE channel output which you don't want in a sub for the rears.
The reason I suggested using speaker level, is the leads are already in the area and you don't have to run a long line level lead/s.
Going to bed.............Zzzzzzzzzzzzzzzzzz
paulspencer said:Rob,
Doesn't it concern you that there may not be very much signal going to the subs in the surround channels? What if they get bored and just sit there gathering dust?
I'm inclined to agree with using the bass from the main speakers, but subs for surround channels? hmmmmmm
How many subs? 3?
Tiroth,
What kind of movies did you look at? How much of a sample of movies are we talking about here?
The surround speakers in a comercial cinema don't look like they could handle any bass at all for a large space. Does this suggest that bass just isn't mixed to surround channels, or are DVDs mixed differently than the sound track used in cinemas?
Hi Paul,
When I finished my main L/R bass units, I moved my sub to the back of my room and used the speaker level connectors with the rears set to large. Yes the sub was being used, not gathering dust. For me it will be worth it, for others who knows?
I'm looking at a 2x12 sub for rear duty, with an opamp based 'mixer' and active x/o to turn the rear left/ right /centre bass into 1 mono sub channel with an x/o to match my surrounds.
WRT cinema sound, they don't really bother trying to get that low in theaters, just to hit the volumes required. I've got a feeling they run the rears full range with the surrounds going as low as they can..
Have a look here for some 'pro' cinema equipment info.(it's where I bought my pair of pro amps for my subs)
http://www.fproj.com/
Cheers
Rob
I thought the THX spec called for a rollof at 80Hz for everything but the LFE or subs? If that's true, then why not gather up and mix anything sub-80Hz from ALL channels and send it to the LFE - OR - if you have full-range speakers in the front (perhaps with integral subs built in) send it there?
Outlaw Audio has a Bass-management unit (for just one example) and it seems to allow this. Am I missing something? It appears to me that, with all the differing "standards" out there, the user is stuck with a fairly elaborate bass management scheme depending on whether the speakers are "full-range", multiple subs are used, the front are "full-range, etc., etc...
Outlaw Audio has a Bass-management unit (for just one example) and it seems to allow this. Am I missing something? It appears to me that, with all the differing "standards" out there, the user is stuck with a fairly elaborate bass management scheme depending on whether the speakers are "full-range", multiple subs are used, the front are "full-range, etc., etc...
>I thought the THX spec called for a rollof at 80Hz for everything but the LFE or subs?
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Not sure. I read what seems to me to be conflicting info on their site. Anyway, DD/DTS rules, so I would be inclined to design a system around them unless a complete THX certified one is used.
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>If that's true, then why not gather up and mix anything sub-80Hz from ALL channels and send it to the LFE - OR - if you have full-range speakers in the front (perhaps with integral subs built in) send it there?
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Isn't this what folks already do?
GM
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Not sure. I read what seems to me to be conflicting info on their site. Anyway, DD/DTS rules, so I would be inclined to design a system around them unless a complete THX certified one is used.
====
>If that's true, then why not gather up and mix anything sub-80Hz from ALL channels and send it to the LFE - OR - if you have full-range speakers in the front (perhaps with integral subs built in) send it there?
====
Isn't this what folks already do?
GM
I may be wrong about this, but I believe the THX standard limits the both high and low frequency signals going to the surrounds and/or center. Hense for just home theater, surrounds with capabilities below 80Hz may be pretty much wasted. However, this is not necessarily the case for SACD or DVD-Music. The recording studio has more latitude about what it chooses to send to which channel.
Consequently, the question may hinge on what are these speakers to be used for.
Consequently, the question may hinge on what are these speakers to be used for.
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