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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Subwoofer Forum => Topic started by: Gordon Brinton on April 08, 2018, 11:46:16 am

Title: Observation: Many subs seem most sensitive at around 100Hz.
Post by: Gordon Brinton on April 08, 2018, 11:46:16 am
I mix a lot of rock and modern country bands in small venues, so levels can get a bit strong in the heat of the night. I generally don't go much over 100dB, but still, that sounds fairly loud in a typical bar or banquet room.

I've owned several different brands and models of subs over the years, and mixed on even more that were owned by others. In my opinion, many of them, regardless of type, seemed to be more prone to feedback at or near 100Hz. This especially if they are on or against a hollow wooden stage that transfers vibration.

I frequently end up notching sharply at 100Hz just to squeeze out a bit more punch or high-passing vocals and instruments to keep things under control. Even my front-loaded 18's that are supposedly flat (+/- 3dB) from 40 to 120 seem to be more sensitive at 100Hz than they are at 60 and 80Hz. They have a fixed crossover at 120Hz, so I must deal with it.

I was just wondering if anyone else has noticed this.
Title: Re: Observation: Many subs seem most sensitive at around 100Hz.
Post by: Paul G. OBrien on April 08, 2018, 12:41:56 pm
They have a fixed crossover at 120Hz
I bet that is your problem. What subs are they? Are you high passing the tops at 120hz too or running them full range? An 80hz low pass on subs sounds better to me and I never run tops full range... always crossed at the same frequency or higher than the subs.
Title: Re: Observation: Many subs seem most sensitive at around 100Hz.
Post by: Ivan Beaver on April 08, 2018, 01:23:46 pm
All you have to do is to look at the freq response graphs of various subs, and that will answer the question on sensitivity.

But yes, in general, most subs are higher in sensitivity at the higher freq.
Title: Re: Observation: Many subs seem most sensitive at around 100Hz.
Post by: Riley Casey on April 09, 2018, 09:15:42 am
High passing vocals should be the default starting set up for any live performance micing. There is nothing you need below 120hz on a male voice and 140 for a female voice and those choices are easily dialed higher if the acoustics demand.  There is no reason your stuck with 120 the low pass on your subs either.  Feed the subs from an aux buss with an EQ cut at 100 hz and I suspect your mix will clean up noticeably.



I frequently end up notching sharply at 100Hz just to squeeze out a bit more punch or high-passing vocals and instruments to keep things under control. Even my front-loaded 18's that are supposedly flat (+/- 3dB) from 40 to 120 seem to be more sensitive at 100Hz than they are at 60 and 80Hz. They have a fixed crossover at 120Hz, so I must deal with it.

Title: Re: Observation: Many subs seem most sensitive at around 100Hz.
Post by: Don T. Williams on April 09, 2018, 11:12:47 am
High passing vocals should be the default starting set up for any live performance micing. There is nothing you need below 120hz on a male voice and 140 for a female voice and those choices are easily dialed higher if the acoustics demand.  There is no reason your stuck with 120 the low pass on your subs either.  Feed the subs from an aux buss with an EQ cut at 100 hz and I suspect your mix will clean up noticeably.

+1 for high-pass as the default setting.  There are still a few mixers out there with 6 dB/octave HP filters which are better than nothing, but barely usable.  Probably designed by the same people that design 120 Hz or 150Hz low-pass on a stand alone sub. Duh!
Title: Re: Observation: Many subs seem most sensitive at around 100Hz.
Post by: Gordon Brinton on April 13, 2018, 02:53:57 pm
Thanks guys. I already know how to deal with it. I've been high-passing vocals and such for over 30 years now. And I've experimented with almost every conceivable crossover routine known to man.

I was just making an observation about many subs in general, prior to applying processing.
Title: Re: Observation: Many subs seem most sensitive at around 100Hz.
Post by: Tim Weaver on April 13, 2018, 06:14:22 pm
I wrote this a few years ago, but the topic still comes up a lot. Setting the highpass and low pass at the same place is only "correct" if both speakers are playing at the same volume (flat response). Since rock and country like a lot more low end, the subs are always turnt, as our rapper friends would say....

https://www.prosoundweb.com/channels/live-sound/tuning_without_tools_working_through_a_system_to_get_it_up_to_speed1/
Title: Re: Observation: Many subs seem most sensitive at around 100Hz.
Post by: Mark Wilkinson on April 13, 2018, 08:22:38 pm

I was just making an observation about many subs in general, prior to applying processing.

Yeah, I agree about 100Hz sounding louder, but i don't think it's just a matter of looking at response curves, or pre vs post processing.
Because even with processing where i know i have flat response, 100Hz (and up)  always sounds  louder to me, than the lower sub freqs....
I've just attributed it to the equal loudness contours, fletcher-munson, etc.   
Title: Re: Observation: Many subs seem most sensitive at around 100Hz.
Post by: fedele de marco on January 09, 2020, 06:20:44 pm
Ask to Fletcher & Munson
Title: Re: Observation: Many subs seem most sensitive at around 100Hz.
Post by: Luke Geis on January 09, 2020, 10:14:38 pm
I like to use as low a crossover as I possibly can for subs myself. I like to make the tops do the majority of the work. Most tops these days ( 12" and up ) can easily work down to 80hz safely and with no major issues. So I will cross the tops over around there typically and then work the subs in from the bottom up. By that I mean, I start as low as I can and only go up as much as it takes to fill in the blanks. I can usually get away with a crossover on the subs around 60-70hz. If it starts getting too boomy I will try and work the tops down a little further until the balance is good and I have as low a crossover on the subs as I can get and not be beating the tops up too much. 
Title: Re: Observation: Many subs seem most sensitive at around 100Hz.
Post by: Tim Weaver on January 10, 2020, 02:05:26 pm
This is a 2 year old thread. I'm assuming dude got his shizz figured out......