live sound - subs on auxes?

[audiothings]

still figuring out the ropes, when it comes to live sound.

last night's show, the audio system dude had set up the system (m7cl/vertec) such that the subs are fed by an aux... (rock band - 2 gtrs, bs, kybd, drms, vox) ... he said that all the great guys he works with do it like this. i've worked this way for theater gigs, but never done it for music. anwyay, i decided to give it a shot since i've usually been unsatisfied with the low end in my live mixes for this type of music ("one note bass" syndrome!)... i sent ONLY the kick drum and the bass to the subs... the show went great, best low end i've ever got in a situation like this... chest thumping, clear and with none of my attention distracted by the crossover point.

question: is this usual way/always the best thing to do? any reason why i should not stipulate it in my tech riders? was this a one-off success by any chance?

thanks,

[Remoteness]

I also like the "subs on aux" idea.
Why have non-bass related instruments mucking up the low end response?
It's nice to only have exactly what you're looking for in the subs.

[ears2thesky]

I usually put vocals on one subgroup, guitars on another, drums on another, and bass/kick on another. If there are keys or horns I'll put them on their own. I like having independent control of the bass/kick with out changing house EQ or channel balance between them. I also run the individual channels to the stereo bus and the subgroups. This gives me more gain potential so I don't have to push channel faders past unity. I will usually apply compression to the group since I generally avoid compressing individual channels if I can help it.
I always run a compressor on the vocal subgroup squashing it pretty good. Having it on the group allows me to mix the compressed signal with the uncompressed signal (of the channel) to taste getting fat vocals without destroying the dynamics of the performance.
When I do a reggae or hip-hop show I will feed the subwoofers directly from the bass/kick group, but for most stuff I run the PA patched in the typical way.

[Geert]

It's a popular technique that has some advantages, but it's not a guarantee for a good sub. It's also not impossible to get a good sub when not using aux sends. It all depends on the quality of the equipment and the skills of the system engineer.

For me the biggest advantage is it gives me control over the volume of the subs, so I can balance it to my own taste. Otherwise I have to use the master EQ's for this, which is less than ideal.

I often use an aux feed combined with a typical setup. In this case I make sure to have a well controled sub sound on the master output, and the kick and bass can get some extra using the aux sends.

Geert

[Roland]

I've used aux fed subs several times before, the only reason I may not use it is because I may be using a system that someone else has put in or done the basic set-up on and that might complicate things when multiple people are involved. That being said, if you have a sensible approach to live sound, non aux fed sub's are not a problem anyway, obviously YMMV.

Regards


Roland

[noamraz]

I have already mentioned this method earlier this year in the forum, i will always prefer having control over the system's components when applicable and agreed by all users.

In my opinion this is the best HPF around, or better i call it - Virtual HPF.

[TehGuitarist]

Personally i think sub on auxes, while perfectly fine, compromise your room tuning.

This is the way i was taught (and meyer teaches for that matter).

Just put your sub on a subgroup or whatever you can just assign the channel to and thats it, not variable, just assigned or unassigned. Then grab your favourite cd and tune the system. So this is all elementary crap yes? Well think about it this way, you just spent all that time tuning your system so the sub works perfectly with the other speakers, and then, if you have the sub on an aux, you completely destroy your balance by adding more or less etc etc etc. Have too much bass from the bass guitar? Shelving eq.

Granted this won't always work but personally i think if you've tuned your system, dont go undoing all your work. If you're on an analogue desk the eqs might not be wide enough etc also so sometimes you just can't do it that way.

So not saying sub on auxes is a bad thing, just some food for thought.

[Derrick Camby]

Originally Posted by TehGuitarist

Personally i think sub on auxes, while perfectly fine, compromise your room tuning.

This is the way i was taught (and meyer teaches for that matter).

Just put your sub on a subgroup or whatever you can just assign the channel to and thats it, not variable, just assigned or unassigned. Then grab your favourite cd and tune the system. So this is all elementary crap yes? Well think about it this way, you just spent all that time tuning your system so the sub works perfectly with the other speakers, and then, if you have the sub on an aux, you completely destroy your balance by adding more or less etc etc etc. Have too much bass from the bass guitar? Shelving eq.

Granted this won't always work but personally i think if you've tuned your system, dont go undoing all your work. If you're on an analogue desk the eqs might not be wide enough etc also so sometimes you just can't do it that way.

So not saying sub on auxes is a bad thing, just some food for thought.

co-sign.

[TehGuitarist]

Oh and just to add, i just realised that you were on a digital desk, there is no actual reason not to (put them on non variable sends), you can adjust ALL of your parameters.

So please correct me if i'm wrong, but THAT is how the big boys do it. Or if they don't they must have a damn good reason not to that i'm not aware of.

[hbphotoav]

Installed flown D&B T-10 line array rig with three cardioid subs flown and a pair of dual-18 B2s on the floor. We run stereo (L/R) with everything assigned through the flown array, and assign bass, kick and keys to the Mono send as well, which drives only the B2s. The flown subs are shelved off around 80 Hz; the B2s work 35-80Hz. Nice clean low end, with very little handling noise, stage thumps, etc., through the B2s. The system was tuned with the output gains normalled, allowing a bit more or less thump with the Mono fader. Works for us.

[Jim vanBergen]

Subs being driven off their own path is a traditional approach. Whether it's driven off an aux, a group, a mono mix, or a matrix, etc it's a smart approach to isolate the mix and not take the sub information off the main mix.

Some FOH guys don't understand this, and can't wrap their heads around what a "Matrix" is or how it works, while understanding aux mixes perfectly. Go figure.

But you don't want keys or guitars sending information to the subs and muddying up the mix. I prefer an aux because I can send more of a specific mic or DI to the sub mix, and with instruments like bass guitar, I want the perfect balance for the instrument which may incorporate stage amps, wedge and sidefill volume, mid-high, plus amount driven to subs- and that's different for any input I want driving the subs. Some metal bands are all about huge kick and bass timed together; while I've mixed some bands who need a lot more in the subs than others, and bands with DJ's who need more info to the subs than the kick.

Most riders specify subs driven from FOH on a post-fader aux send with it's own EQ and delay. Same basic idea for front fill speakers or outer fill speakers.

[c.gymer]

When I do this I run the subs from a mono fader. I'm not a fan of doing it from aux sends. That said, I've never done this on a big show so you never know...

All things being equal, I've not really had any benefits from this approach and I don't think it makes a FOH mix any better. It's just another way of doing it.

By the way this is only in regards to sub 500 shows. Bigger shows are obviously a whole other ball game so YMMV.

[tamasdragon]

I love the idea, worked that way, but somehow at the end, I still prefer "all in one" systems without aux driven subs. If properly set up, it somehow more coherent for me.
Given a good band, a good and well tuned system, I have never felt that I need aux-sub.
Although in a less than ideal situation it can easily be a lifesaver.
Tamas Dragon

[Enginearing]

there are certainly advantages in doing things this way.... it can really clean up the bottom end, though it may be neccescary to run the rest of the system full range, (or at least tweak some processing)

Jon Burton (FOH - prodigy) specs his system with a centre cluster of subs, seperate from the rest of the PA and really rides them for effect at certain points during the show. As you would imagine there is a lot of bottom end going on with those lads... it kind of goes from 100% to 130% at times... (the PA even gets time aligned to Liam's fill)

[H...]

Subs on an aux - works on stage for a drum fill & a sub.

I hate it on a FOH rig - but then again i hate alot of the new computer predicted trends that PA system designers and the techs that go out with it do.

[Roland]

For me a lot would depend on the band I was doing. If it's music that is clearly defined needed in sub/not needed in sub then it's obviously a good option, however there are bands and musical styles where the line is less defined, then the use of bass filters on channels is probably a much better option. With bass filters properly deployed I doubt the benefits would be so obvious. YMMV

Roland

[fifthcircle]

I like the flexibility that putting subs on an aux gives me...

The problem with doing hard assigns is the same with having subs integrated in with the mains. You can have multiple sources that would work with the subs, but you need differing amounts in them.

For example: you may want to crank a kick drum in the subs to give that visceral thump in the chest that folks like. However, you may have a bass player that needs to go in the subs as well. Putting that much bass into the subs makes the bass sound muddy- you loose the articulation that just lowering the send a little would fix.

I have plenty more examples, but this is just one... Having control over the major components of your system is never a bad thing.

--Ben

[TehGuitarist]

Originally Posted by fifthcircle

I like the flexibility that putting subs on an aux gives me...

The problem with doing hard assigns is the same with having subs integrated in with the mains. You can have multiple sources that would work with the subs, but you need differing amounts in them.

For example: you may want to crank a kick drum in the subs to give that visceral thump in the chest that folks like. However, you may have a bass player that needs to go in the subs as well. Putting that much bass into the subs makes the bass sound muddy- you loose the articulation that just lowering the send a little would fix.

I have plenty more examples, but this is just one... Having control over the major components of your system is never a bad thing.

--Ben

Shelving eq, its a big ass volume knob for whatever frequencies

[c.gymer]

Originally Posted by Roland

For me a lot would depend on the band I was doing. If it's music that is clearly defined needed in sub/not needed in sub then it's obviously a good option, however there are bands and musical styles where the line is less defined, then the use of bass filters on channels is probably a much better option. With bass filters properly deployed I doubt the benefits would be so obvious. YMMV

Roland

+1

[valleysound]

If you just take an aux send to the subs with no processing and no tuning, it's rather pointless. I find aux fed subs clean up the mix tremendously. Works better than HPF in my opinion, but I still use HPF as needed to get the sounds I want.
One thing to consider is that once the PA is tuned with aux subs, if you change the main faders, it will throw off the system tuning. The gain on the mains and aux subs must always remain the same with respect to each other.

[Jim vanBergen]

I have to really agree with Ben & Paul, and disagree with (sorry don't know your name) TehGuitarist - I love real shelving EQ for studio mixing, and HPF's are an important part of live sound mixing- but one simply can't assume that for all kinds of music, and all different artists, that you will want to have the exact same amount of bass guitar in the subs as you do kick? When mixing bands like NonPoint, Saliva, Trust Company, and Staind, I want a real level of separation between the kick and bass in my sub system, while the bass is dominant over my bottom octave in the mid-high system (maybe as low as 160 but surely from 200-400 Hertz), the kick drives from 40-120 Hz, and if you're mixing metal, rap, hip-hop or even pop, you might need to have a specific/custom ratio of your bass, low keys, and kick- but if I drove T.I. 's mix off a subgroup or off the mains, you'd never hear all the parts cleanly. Separating each musical element's relationship to part of a system can be very important, and when forced to drive subs off the main L/R mix, I often mult out the kick, bass, left key, and backing track channels just for sub so that I can use shelving EQ just for subs and drive the show the way it needs to be driven to represent the artist and their song correctly. It's not so hard to get the relationships to represent with a four-piece band for 25,000 people, but try the same thing with a philharmonic orchestra, symphony, or big R&B artist with eight elements that want some amount in the subs and another in the lowest two octaves of the mid-high rig.


Of course, there are many ways to skin a cat, or mix a show. All that matters in the end, is that it sounds right, and still sounds correct when the wave gets where it needs to go. Interesting thread.

[jude]

i usually just run subs from the mix buss to processor and sum to mono. that said if i have in fills i'll usually put subs under them and run them of a spare aux, via another processor

[valleysound]

Here's a good test. After sound check, on a PA without aux fed subs, mute all outputs except the subs. Give your vocal mic a slap with you palm. Are you getting some sub output? Try the same with the high hat mic or overheads, violin, mandolin, etc or any other mic where you do not want any sub output. I'll be willing to bet that there is still going to be some low frequencies making it to the subs. Add all those mics up and there is going to be enough sub frequencies to noticeably add to the mix. Subtle, yes, desirable, no.

[jude]

hpf's are your friend there

[H...]

Filters Filters Filters, Correctly stacked/aligned/tunned PA

[TehGuitarist]

Originally Posted by Jim vanBergen

I have to really agree with Ben & Paul, and disagree with (sorry don't know your name) TehGuitarist - I love real shelving EQ for studio mixing, and HPF's are an important part of live sound mixing- but one simply can't assume that for all kinds of music, and all different artists, that you will want to have the exact same amount of bass guitar in the subs as you do kick? When mixing bands like NonPoint, Saliva, Trust Company, and Staind, I want a real level of separation between the kick and bass in my sub system, while the bass is dominant over my bottom octave in the mid-high system (maybe as low as 160 but surely from 200-400 Hertz), the kick drives from 40-120 Hz, and if you're mixing metal, rap, hip-hop or even pop, you might need to have a specific/custom ratio of your bass, low keys, and kick- but if I drove T.I. 's mix off a subgroup or off the mains, you'd never hear all the parts cleanly. Separating each musical element's relationship to part of a system can be very important, and when forced to drive subs off the main L/R mix, I often mult out the kick, bass, left key, and backing track channels just for sub so that I can use shelving EQ just for subs and drive the show the way it needs to be driven to represent the artist and their song correctly. It's not so hard to get the relationships to represent with a four-piece band for 25,000 people, but try the same thing with a philharmonic orchestra, symphony, or big R&B artist with eight elements that want some amount in the subs and another in the lowest two octaves of the mid-high rig.


Of course, there are many ways to skin a cat, or mix a show. All that matters in the end, is that it sounds right, and still sounds correct when the wave gets where it needs to go. Interesting thread.

Its Leigh for all its worth

And i do agree, not every situation calls for non variable sends to subs. But i did say use shelving eqs as volume knobs, i'm kinda confused as to why you don't think that would work, not insulting or attacking you, you obviously know what you're talking about, but whats wrong with sticking a shelving eq, lets say starting at 400 to cover everything, to use as a volume knob. Actually come to think of it, wouldnt variable sends do that... ahhh now i'm confusing myself.

[valleysound]

Originally Posted by jude

hpf's are your friend there

A "standard" HPF is say 18db/octave. If you set it for 160hz on a vocal channel, you're only down 18db at 80hz. Some of that low end is still going to make it to the subs.
Really, this is all very subjective and the whole process of subs to aux or not is really up to the engineer. It is good to hear all these opinions though!

[Roland]

Originally Posted by valleysound

A "standard" HPF is say 18db/octave. If you set it for 160hz on a vocal channel, you're only down 18db at 80hz. Some of that low end is still going to make it to the subs.
Really, this is all very subjective and the whole process of subs to aux or not is really up to the engineer. It is good to hear all these opinions though!

18db in audio terms is a huge amount. I respectfully sugest that there are a lot more problems facing PA sound than some possible spill into the subs from filtering. Most rooms are far from ideal when it comes into acoustics and questions of coverage and room modes all come into play. You also have issues of "power alley" and lobing that severely affect most live sound systems.

as I said above, aux fed subs my be a good idea for many standard rock bands (i.e. guitar, bass, drums and vocals), but the issues becomes much more complicated when many other instruments that cross the barrier start to be involved. Aux fed subs start to act like fixed point, bass eq's, it's not just a point of adding more or less. particularly with things like bass guitar, you could quite easily "skew" your sound. IMHO rooms with good acoustics still sound good on a regular system, a bad room isn't going to be fixed by aux fed subs.

Regards


Roland

[Jim vanBergen]

Leigh, it's a pleasure to meet you my friend, thanks for sticking with me on this-
I see your point and think your approach would work, for me personally I need the energy many instruments (and male vox) generate in the 200-400 Hz range I use in the mid-bass from the main PA. Every octave has multiple elements fighting for space, right?

I simply prefer variable sends (aux driven subs), especially as I like to control how much of what element goes into which system (my front fill systems for rock shows are almost all Vox, while in country or classical it all depends on whats coming off the stage. I totally respect the other opinions, as every engineer has their own way of doing things and making it work. I apologize if I was being a bit of a **** on this... I know what works for me, and when I've had to system tech for guys like Dave Natale, found they used the same approach most of the time for systems that were designed to complement a specific venue. For engineers who worked with the same act and same PA every day, they may have a much easier time dealing with stereo mix that translates perfectly to the well-tuned four way PA model.

Warmest regards to all-
JvB

Originally Posted by TehGuitarist

Its Leigh for all its worth

And i do agree, not every situation calls for non variable sends to subs. But i did say use shelving eqs as volume knobs, i'm kinda confused as to why you don't think that would work, not insulting or attacking you, you obviously know what you're talking about, but whats wrong with sticking a shelving eq, lets say starting at 400 to cover everything, to use as a volume knob. Actually come to think of it, wouldnt variable sends do that... ahhh now i'm confusing myself.

[mixedupsteve]

Another advantage of aux fed subs is it often gives you the opportunity to deliver a cleaner signal to them without getting crossovers and filters and processing in the path. (or at least less)