How to Choose the Best Subwoofer

General Rules to Follow to Get the Most Out of Your Subwoofer Investment

1. Do it Right the First Time

     We cannot stress this enough. This is probably the biggest problem we have noticed new customers encounter. Everyone wants to spend half the money and get twice the performance. When you get your new purchase out in the real world you are going to discover you need the output and reliability of the good stuff. The fact of the matter will be when your gig goes down in the middle of the show, the savings you thought you could get away with is not going to matter at all. You will probably never get hired again for that job and you're going to have to purchase the gear you should have gotten in the first place. You will painfully discover the "gig gone bad formula." It takes about 20 good shows in a row to undo a show gone bad. The reason we are stressing this issue is because we had to learn it the hard way, just like everyone else.

2. Don't Mix and Match Boxes in the Same Frequency Range

     It's important that you use all the same types of sub designs together and all the same mid-high box designs together. Different cabinet designs have a tendency to fight with each other acoustically. Bass horns have a different arrival time than direct radiating, vented type boxes. 15 inch speakers have a different sound than 18 inch speakers. Horn loaded mid-high boxes throw different than non-horn loaded types. Quasi-horn loaded vented boxes have their own set of conflicts all together. Unless you are an experienced engineer it's best to stay will all the same type of box design in a given frequency range. You will have a much cleaner overall sound, prevent a mess of unnecessary headaches, and you will save amplifier power too.

3. Understand High Power Subwoofer Use

     All Ramsdell Audio subwoofers are designed to reach maximum driver/cone excursion at their rated power levels. We believe that you will achieve the best use of speaker output and amplifier watt requirements by using medium x-max (cone excursion), high-efficiency woofers. You will no doubt find varying opinions on this subject, but after 30 years of production and competing in product shootouts we believe that this is the best way to go. The quicker a woofer can respond to a signal, the more accuracy and control it has reproducing it. For high power subwoofer use, make sure you have a 24 db per octave high pass filter available. You will need to adjust it so that you don't allow frequencies in your signal to go below the tuning frequency of the enclosure, causing excessive cone excursion. During such cone excursion, when the voice coil begins to leave the magnetic gap, your overall system damping factor begins to deteriorate. The speaker begins to lose control of itself and the amplifier begins to lose control of the speaker. If this continues, electrical or mechanical damage to the speaker will happen and that is bad.

4. Make Use of Compression and Limiting

     Even if you use multiple safety measures, make sure your amplifier comes with a soft clip limiting circuit. During use, make sure that it's not run past occasional blinking. If the limit circuit stays on to long it will turn the signal into more of a continuous level and cause voice coil over heating. This will lead to less acoustical output and eventually thermal speaker failure.
     Your amplifier will also perform better running at 4 Ohms than 2 Ohms. The lower the impedance, the more demands are placed on the amp's power supply. If you're running at 4 Ohms and happen to lose an amp in the middle of a show, you can always transfer speakers to another amp. This would probably not be possible if you were already using the amp at a 2 Ohm load.

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Reprinted with permission of www.RamsdellProAudio.com © 2004 Ramsdell Pro Audio. All Rights Reserved.