SBAL's online help



Frequently Asked Questions About Sound Bridge Speaker Products

1. What Does "Clipping" Mean and Why is it Bad?
Clipping usually means that the maximum output of the amplifier is being exceeded and the tops of the signal peaks are being "clipped" off. During these times the cones of the loudspeakers are essentially receiving a DC signal. This means that most of the energy from the amp is heating up the voice coil instead of moving the cone. Usually loudspeakers fail or burn-up because of this heat. (aka. Thermal Failure) You should also be aware that any clipped signal in the chain can blow a loudspeaker even if the amplifier isn't at full output. Most loudspeakers fail because they are driven by too small an amplifier. The power ratings for a loudspeaker are only valid for unclipped input signals. So, to avoid problems, always operate your gear safely below "clip level".
2. How Much Power do I Need?
In general the bigger the amplifier the better. Once you reach an amplifier's maximum output, you cannot get anymore out of it. Push the amp input signal any harder and your output will be distorted. It is also true that most speakers will handle momentary peaks far in excess of their rated power handling, if these peaks are clean. (not clipped) SBAL speakers are so efficiently designed that you could easily use as little as 10 watts for certain applications. We would recommend however that you have at least a 400 watt per channel amplifier ( 8 Ohms). This will allow you to get more out of your system and provide you some safety margin in the event you need it. (headroom)
3. How Many Speakers Can I Put on One Amplifier?
Most SBAL speakers are rated as a nominal 8 Ohm load. This means that the amplifier "sees" an average of 8 Ohms of most of the musical range when it is hooked up to one speaker. Some times it is a little less but most of the time it is a lot more. Most professional amplifiers would prefer to have an 8 or 4 Ohm load on each side of a stereo amp. If you connect two speakers in parallel to one side of an amp, the amplifier "sees" a 4 Ohm load. In most cases this is about as low of an impedance as you should use. This is true even if the amplifier is rated to 2 Ohms. If you run a cable from the amplifier to an SB speaker and then come out of that speaker into another (daisy chain) you should have a 4 Ohm load. In the case of a stereo amp we recommend no more than two speakers per channel. If you would like to hook up more, you should consider more amplifiers or wiring the speakers differently. When it comes to wiring speakers, here are the basic rules: Speakers in parallel - divide the impedance of the speaker by the number of speakers to determine the load of the amplifier. Speakers in series - multiply the impedance of the speaker by the number of speakers to determine the load of the amplifier.
4. How Should I Aim the Speaker Stacks?
You want to aim your speakers so that they cover as much of the audience as possible. Try to aim the speakers so that as little mid/high sound gets reflected off of the walls as possible. If you have a pair of speakers aim them towards an imaginary point about half to two-thirds of the way back into the middle of the audience. If you have more than two speakers on a single side, it is often a good idea to "splay" them out some to widen your horizontal coverage angle. For "long throw" application it is often a good idea to stack your speakers on top of one another with tweeters in each box as close together as possible. [For example- place the top cabinet upside down on top of the bottom speaker and aim them both straight ahead.] Remember that low frequencies (below 100 Hz) have very long wavelengths and are fairly non-directional. It is a good idea to keep your subwoofers low on the floor and next to boundaries like walls/corners. On the other hand high frequencies have very short wavelengths and dissipate very quickly. So, keep these aimed high over peoples heads in the front row.
5. What Kind of Speaker Cables Should I Use?
It is always a good idea to get heavy gauge speaker wire to connect your speakers to the amplifier. There will be a lot of current going to your loudspeaker. In the real world nearly 90% of your problems will stem from bad connections between your equipment. We recommend at least 16 gauge wire but prefer 12 gauge. It is also a good idea to keep your cable runs from your amplifiers to your speakers as short as possible. Try not to exceed 35 feet - and do not coil up the excess wire. If you must go further than 35ft, consider moving your amps or getting heavier gauge wire.
6. How Can I Protect My Speakers From Being Over-Driven?
If you are having problems with "blown" speakers you may want to consider some added protection. You may want to use a compressor/limiter in the signal chain before the amplifier that will keep your signal from clipping. If you want some protection but cannot afford this solution try adding some inline fuses on your speakers. You can use standard fast blow AGC fuses in series with one of the speaker leads. To calculate the proper value use the following formula: Amps=square root (Watts/Ohms) For example begin with the speakers' continuous power rating (i.e. 450Watts) Amps=square root (450/8) Amps=7.5 Be conservative and experiment, start with a lower value and work your way up. Ideally you want the fuse to blow before your amp goes to clipping.
7. How and Why Do I "Biamp" a Speaker?
There are several ways to "biamp" a speaker. Several of the Soundbridge speaker models feature a switch that will allow the user to quickly switch between the internal full range "passive" crossover and biamp mode. Biamp mode requires an external active crossover and another amp. So, why biamp?? There are several reasons . . . First, your system will have more overall flexibility. Second, it is easier to control the sound of each speaker. Be aware that all passive crossovers use up some of the amplifier power and you have more overlap in the frequency between the drivers inside the speaker cabinet. When you biamp, more power can be channeled into the woofers and distortion level often goes down. The trade-off again is that you must use another amp and an external active crossover. If you want to biamp it is usually wise to first acquire a subwoofer. You can then biamp between the subwoofer and the full range cabinet.
8. How Do I "fly" a Speaker?
Please stop - read and understand the application instructions thoroughly before flying any speaker. Misuse of a product may result in damage, injury, and even death. Never suspend a speaker from the handles!! Always consult the speaker manufacturer to ensure the working load limit on the speaker hardware and enclosure is not exceeded. Consult a professional rigger or structural engineer prior to suspending loudspeakers from a structure not intended for that use. Always know the working load limit of the structure supporting the loudspeaker array.
9. Why use a Subwoofer?
True subwoofers greatly enhance the response in an audio systems' very low end. The difference can be heard and felt! A subwoofer can provide the punch or impact that is lacking in many small systems. But, in order to feel bass you have to move a great deal of air. A subwoofer is designed to do just that and is really more of a specialist in reproducing the lowest fundamentals in music. In most cases it is the best way to improve an existing system. It is a great way to lower system distortion and make your sound system clearly more understandable. It is often more cost effective than buying bigger amplifiers or more amps.
10. How Do I Get More Gain in the Mains and Monitors?
Here are some basic methods you can try to solve this problem: Try placing a microphone in the middle of the room in the middle of your speaker stacks. Slowly bring up the gain until the system starts to feed back. Now, bring down the levels of each of the squealing frequencies on the main system eq. Be careful not to bring it down too much - just enough to stop the squealing. Keep bringing the gain up until you have the levels you want. Now, try playing a CD you know very well and adjust the eq until it sounds the way you want. Finally, grab the microphone and speak into it. Now adjust the vocals until it is clear and crisp. This is the quickest way to get up and running without a great deal of hassle. If your monitors are not loud enough - try to reduce the overall stage volumes first. Pull all of the frequencies below 80 or 100Hz down. Move the monitors closer to the performers' ears by placing them on cases or using them as side fills. If all of this does not work, try cleaning and/or changing out the microphones. Remember - its an art as much as a science so be patient. Good Luck!!