# Flown Subs



## paulslhac (Jun 20, 2014)

Hi everyone. Basic question. Why do people fly sub's when it so evidently effects their performance?

I understand that they are meant to provide a more 'even' coverage to an audience but it absolutely ruins the true low frequency 'feeling'. Why!?!?


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## jkowtko (Jun 20, 2014)

I'm sure it's very subjective, as are most speaker installations, temporary or permament. Here's my two cents:

1) In some cases it gets them off the floor, opening up valuable floor space In a temporary install it might simplify the installation (e.g. two line array clusters w/subs vs separate subs), and in a permanent install it permanently leaves the floorspace open

2) co-location of sound source. At the higher LFE frequencies can people start to discern where the sound is coming from? If so, then co-locating mains with subs will help with sound perception.

3) they don't believe that hanging subs on cables will cut their performance. If the subs are heavy enough to absorb a punch, and the resonance of the cable assembly is below the lowest LFE frequency, then theoretically it should not affect the sound

4) When subs are flown (or when they're installed on the floor, for that matter) they may not be place properly w.r.t. reflective surfaces to provide the best sound. Sub placement issues may be distinctly different from mains placement issues.


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## JD (Jun 20, 2014)

Much like the proximity effect of a microphone (but for totally different reasons  ), subs on the floor produce more apparent bass. In this case due to the mirror effect. There is a tradeoff though.. People in the first few rows get somewhat blasted. In addition, although low freq waveforms are very long, they do get somewhat absorbed by said blasted people. Flown subs give an even field of output as there is no front-of-stage hot spot. I've watched over the years (1970's to today) Subs (or as we used to call them "bass bins") evolve from floor to scaffold to flown, and now some are returning to the floor. Oh well, such is life!


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## avare (Jun 21, 2014)

paulslhac said:


> Hi everyone. Basic question. Why do people fly sub's when it so evidently effects their performance?
> 
> I understand that they are meant to provide a more 'even' coverage to an audience but it absolutely ruins the true low frequency 'feeling'. Why!?!?



Please explain your premise of "it absolutely ruins the true low frequency 'feeling'."

Andre


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## museav (Jun 28, 2014)

paulslhac said:


> Hi everyone. Basic question. Why do people fly sub's when it so evidently effects their performance?
> 
> I understand that they are meant to provide a more 'even' coverage to an audience but it absolutely ruins the true low frequency 'feeling'. Why!?!?


How do you feel it affects the performance of the subwoofers and what do you think is happening?

Folks such as Pat Brown (http://www.synaudcon.com/site/author/pat-brown/how-boundaries-affect-loudspeakers/) and Dave Gunness (http://www.fulcrum-acoustic.com/assets/pdf/whitepapers/comments-on-half-space.pdf) have addressed boundary loading of subs and shown that not only is the assumed imcreased level from boundary loading not actually typically applicable but that any increase in perceived or measured SPL is due to increases in the indirect sound, distortion and so on, increases that are not necessarily desirable.

It may also be worth noting that flying the subwoofers with the mains can simplify or eliminate many of the crossover and system tuning issues that are generally associated with having flown mains that are physically separated from ground stacked subs.

The tradeoff that is oten involved may be that of the tactile aspect of any related structureborne vibration versus coverage. Ground stacked subwoofers may provide some very low frequency coupled structural vibration that is felt rather than heard, but often at the expense of inferior coverage, Conversely, flying subs can generally provide better low frequency coverage but at the expense of losing the 'feel' rom any related structural vibration. Maybe the ideal woul be to have flown subs covering most of the low frequency spectrum in conjunction with dedicated effects subwoofers that are physically coupled to the structure and reproduce only the very low frequency content.


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## Lextech (Jun 28, 2014)

Quite often flown subs are part of a crossed over, full range system. You get the benefits of a complete system, time alignment and the physics behind the manufactures design. If you feel that you need extra low end, a separate sub system on an aux send can be a help. You feed it only those instruments that actually contain information in that range, kick, bass, tuba, you get the idea. This way you don't have to do radical eq to a vocal mic or the system in general to prevent mud or feedback.


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## JCBigler (Jun 28, 2014)

Greetings, 

In my building I have flown subs in two of our theatres. One is an ~430 seat proscenium theatre, the other a ~200 seat black box theatre. 

In the 430 seat theatre, I have a pair of Meyer M1D line arrays with a cardioid sub array made of 3 Meyer M1D Subs flown at center. By adjusting the delay of the center sub in the array (which is installed facing upstage), I am able to steer the cardioid lobe of the sub array down and into the center of the audience to provide a very tight and unified low frequency image right in the center of the audible image for the audience. We don't do a lot of heavy rock shows or dance shows, so it is plenty for the theatre, modern dance and various world music events that we do there. The plus is that it does get them off of the stage floor and by arraying them at center I remove the power alley that occurs when you have subs on opposing sides of the stage. 

In our studio theatre, I have single M1D sub flown from the underside of our catwalk at center between the two Meyer UPJ-1Ps that serve as the main speakers or that room. It is flown purely for space reasons and the convenience of not having to hook up a sub for each show and strike it afterwards.

I should mention that we run AUX fed subs in all of our theatres.


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## TimmyP1955 (Jul 26, 2014)

The subs need to be within 2 feet of or at least 8 feet from any boundary. I often see flown (and ground stacked) subs that don't meet this criteria.


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