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[Evan Kirkendall]

Nick Aghababian wrote on Sat, 05 August 2006 03:39

I guess since i primarly do rock and roll concerts, i really wouldn't want to use aux fed subs.

Hm, my primary work is rock concerts, and I switched to AUX subs at the beginning of the year. I must say, Im never going back to the old method. The bass sounds cleaner, headroom increased a lot and the bass sounded cleaner and punchier.


Give it a shot. You'll like it.



Evan

[Nick Aghababian]

Like i said, i am very young in my career, but i have mixed in about a dozen places with aux fed subs, and never really liked it.

only once have i used the subs on the mono fader like Geri said. and i liked it, but haven't got to play around with it too much

And still, with all that "extra low end energy" I like my LPF and use them alot.

[Tom Howard]

Dave Rickard wrote on Fri, 04 August 2006 22:05

Nick Aghababian wrote on Fri, 04 August 2006 13:44 I wouldn't use Aux's for subs, and expecially not full range speakers. I am a firm believer in letting your crossovers do their job. [...] Have you read this article?    http://www.prosoundweb.com/install/tech_corner/auxsubs.shtml

The article desribes using tops driven without any LF content, like so:


But most people describe running the tops full range. Could anyone shed some light on this? It seems a good idea, and one I might well adapt (theatre & pub/club gigs.)

There is also the concern of aux-driven subs not following the main master faders - is there any routing that solves this? I can't think of anything on a standard analogue desk.

[Mike {AB} Butler]

Nick Aghababian wrote on Sat, 05 August 2006 03:39

In regards to mike, All these problems with subs and vocal mics, i have always been able to avoid by either sucking out all thoes low frequencies with either the EQ, or the Low Pass Filter. Spoken word, Church sound, i never have had a problem.

Sorry, but even with the HPF (NOT LPF, BTW - don't confuse the 2!), engaged, there can still be things that do hit the sub. Depending on the design and slope rate used, a HPF takes an octave or two before it starts to really kick in, so THAT means if your HPF kicks in around 90 or 100 Hz, you can still have quite a bit at 80 hz - well within the reproduction range of the sub! While not destructive, they are typically annoying, amateurish, and disruptive. Better to completely keep out what you don't want fed to the sub.
I agree with the others.. it's pretty commonplace now.. might as well learn how to use it - so you'll be in sync with at least half of the Live-Audio community..  
Regards,

[Nick Aghababian]

Tom Howard wrote on Sat, 05 August 2006 18:59

Dave Rickard wrote on Fri, 04 August 2006 22:05 Nick Aghababian wrote on Fri, 04 August 2006 13:44 I wouldn't use Aux's for subs, and expecially not full range speakers. I am a firm believer in letting your crossovers do their job. [...] Have you read this article?     http://www.prosoundweb.com/install/tech_corner/auxsubs.shtml The article desribes using tops driven without any LF content, like so: But most people describe running the tops full range. Could anyone shed some light on this? It seems a good idea, and one I might well adapt (theatre & pub/club gigs.) There is also the concern of aux-driven subs not following the main master faders - is there any routing that solves this? I can't think of anything on a standard analogue desk.

the "expecially not full range speakers" was in regards to the person who made this thread. He said he was using an aux for the subs, as well as full range.

------

mike, i can see the uses for an aux fed sub system (why else would they have thought it up?), but i just dont like it. I have used it, and know how to, but again with the preference deal, i just do not prefer it.

[Mike {AB} Butler]

Nick Aghababian wrote on Sat, 05 August 2006 21:08

mike, i can see the uses for an aux fed sub system (why else would they have thought it up?), but i just dont like it. I have used it, and know how to, but again with the preference deal, i just do not prefer it.

.. And I just explained to you why it ISN'T "just a matter of preference". Unwanted signals can and do get into the sub - owing to the typical attenuation slope - the lows don't get completely "killed" by being sent through the HPF that are adjacent to the cutoff frequency. You will still have some unwanted stuff there in many cases.
Don't take my word for it. Go out and set up your system. First, with the sub as you use it. Then, as an aux fed.. and the aux fed turned completely OFF on the mic channel you are using for the check - and repeat the same test. You should be able to hear the sub kicking in on 'plosives, handling noise, and such with the sub on the mains signal, with the aux turned up, and NO action from the sub with the aux turned off.
Some still say it's a matter of preference. I'm saying: there is a difference..
Regards,

[Evan Kirkendall]

Nick Aghababian wrote on Sat, 05 August 2006 16:20

Like i said, i am very young in my career, but i have mixed in about a dozen places with aux fed subs, and never really liked it. only once have i used the subs on the mono fader like Geri said. and i liked it, but haven't got to play around with it too much And still, with all that "extra low end energy" I like my LPF and use them alot.

Im only 17, so Im quite 'young' in my sound career too. However, if one of the respected/older memembers on here give me an idea, Ill give it a shot. 99.95% of the time their ideas/suggestions will make things sound better.


Evan

[Tim Padrick]

Thanks to my DriveRack, I've been able to do a direct comparison between standard and aux-fed with a band on stage.  Definitely clearer sounding when running aux-fed.  (Channel high pass was engaged on everything but bass, kick, and toms.)  I have found no down side.

Most subs have a nice little peak someplace, as do many rooms.  Often these peaks are very narrow.  1/3 octave bands just pull out too much of the good stuff.  Parametric please.

A channel's bass control may say "60Hz", but usually that's the frequency at which the control gives maximum boost/cut.  It usually also gives quite a bit of boost several octaves above that, giving one too much upper bass/lower mid (just look at the EQ charts in a console brochure).  One might be able to fix this with the low-mid sweep, if it is not being used for something else.  In contrast, boosting the sub aux level on that channel will give the desired low end boost with much less boost in the octaves above.  Sometimes this gives one a result that is closer to what s/he's looking for.

[Tom Howard]

When using Aux fed subs, do you run the top cabs full range, or cross the LF out of them completely?

[Geri O'Neil]

It's best to use a processor between the subs and the tops and drive them with separate inputs (tops from left&right, subs from aux, group, or mono buss). For one, you'll get a lot of gak from the two low-frequency sources combining. Second, the whole point of this excercise is to remove the various inputs that generate nothing useful in the sub range from the subs. If the tops are running full-range, you have that "nothing useful in the sub range" equation back in, well, the mix, as it were. Not to mention unnecessarily eating up headroom in the full-range speakers' amplifiers.

Geri O