subs for small venue

D

Doug Christensen

Freshman
Feb 18, 2014
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We are a small venue oldies/country band, playing at car shows and small town fairs. The band is a guitar, bass, keyboard and a drummer playing a Roland digital kit. We mix all mics and instruments through a Yamaha board, then out to the amps/speakers. Since pro sound is not provided at these small venues, we have our own PA system. Our old passive system was 2 Yamaha S115IV mains and 2 Peavey 18” subs. We used 2 Tapco amps with a stereo crossover. We typically adjusted the crossover away from the bass side, as it would get pretty “boomy.”
We’ve upgraded our mains to a pair of EV ZLX-15 powered speakers. We want to add a sub, but wanted some of your opinions on what direction to take. Our options would be:

  1. Buy a single EV powered 18” sub. Our thinking is that 1 would be plenty, based on our previous experience.
  2. Buy a pair of smaller powered subs, with a 12” or 15” speaker.
Any advice or opinions would be appreciated!
 
Re: subs for small venue

Doug Christensen said:
We typically adjusted the crossover away from the bass side, as it would get pretty “boomy.”
We’ve upgraded our mains to a pair of EV ZLX-15 powered speakers. We want to add a sub, but wanted some of your opinions on what direction to take. Our options would be:

  1. Buy a single EV powered 18” sub. Our thinking is that 1 would be plenty, based on our previous experience.
  2. Buy a pair of smaller powered subs, with a 12” or 15” speaker.
Any advice or opinions would be appreciated!
Click to expand...
Doug,

Usually the description "boomy" indicates a problem where the subs and mains overlap, and the output of the ported tops usually don't align properly with subs without some time delay and frequency adjustment to get rid of the crossover peak "boom".
It is common to have to pull -6 dB at a fixed crossover point or underlap, for example cross subs at 80 Hz, and tops at 110 Hz to eliminate the boom.

The output of subs is determined by displacement (cone movement X diameter), given the same excursion, 2x12" is a bit more than one 18", 2x15" a fair bit more. Smaller drivers may go lower for a given box size.

That said, to reproduce low bass at the same level as mid bass usually takes more cone area, a pair of 18" may be "about right" for a pair of 15".
Your new tops may have a fair bit more output than the old tops, and will need more bottom to "keep up".

If the powered subs don't have built in DSP (digital signal processing) designed specifically for your top cabinets, you will still need a crossover, EQ (and possibly delay) to avoid a "boomy" overlap area.

Regardless of the sub choice, for small systems I generally prefer using a pair for the convenience of using them as pole mounts, eliminating the trip hazard of tripod stands, and providing a consistent set up, rather than trying to figure the best compromise placement for a single sub at each venue.

Art
 
Re: subs for small venue

We planned on buying the same brand of subs as the mains. The mains are EV ZLX-15P, which have the DSP. Thanks for the info.
 
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