Quote:
Originally Posted by bigben379  Hey guys ive got an ashdown MAG 300H Evo head with the MAG 410T cab, when im playing with my band when rehearsing i have to run the head at just under full volume keep up with the rest of the band ( drums (very loud drummer), 2 guitars, keys and singers). Im really not up to speed with wattage and loads, im just the bass player haha, if i add another cab: 1. will i get more volume? 2. will i run the risk of damaging the head? Cheers for your help!!!! |
Quick answers #1 - yes, #2 - not if the impedance is matched.
Picking the right speakers for your bass amplifier.
Over powering a speaker can damage it and a impedance mismatch can damaged an amplifier. See Eminence‘s webpage Understanding Loudspeaker Data | Eminence Speaker and look under “POWER HANDLING”. And Myers Sound “Making Sense of Amplifier Power Ratings”
Making Sense of Amplifier Power Ratings
Power - the ideal situation is to choose a loudspeaker that has the capability of handling more power than you can provide lending some headroom and insurance against thermal failure.” If you don’t know how much power a speaker cab can handle, slowly turn up the bass amp volume until the speaker starts to sound bad, then turn down the bass or volume until it sounds good.
Ohms - make sure the speaker cab impedance meets the bass amp requirements. Look on the back of your bass amp note the required speaker load (ohms) and make sure the impedances of your speakers match. See
Wiring Diagrams | Eminence Speaker
Stacking Speakers - about 3dB is considered the least amount of SPL gain the human ear can hear and it takes about 10dB to double the volume (SPL). See
dB: What is a decibel? If you have a 100 watt amp with one 12" speaker and you add another 12" speaker you will get the a 3dB increase. You would have the same SPL as a 200 watt amp with one 12" speaker. To get the next 3dB increase you need to double the speakers again so you would need four 12" speakers. Having 4 speakers will give you a 6dB increase in SPL compared to 1 speaker. Then it gets more complex. If you double the 4 speakers to 8 speakers there isn’t a 9dB increase in SPL as compared to one speaker like you’d think, instead you only a 6dB increase compared to one speaker because phase cancellation comes into play. The distance between the speakers causes the sound to reach your ears from the speakers at a different time and this has the effect of canceling some sound so more speakers are better up to a point. Drivers, enclosures, power, impedance, etc all play a role in the SPL. There is no perfect bass speaker enclosure because all loudspeaker enclosures are a compromise of design trade-offs. So just buy speakers you like the sound of and make sure they meet your bass amp impedance requirements. Start with the volume off and slowly turn it up to the desired volume level or until the speakers start to sound bad - then turn down the bass or volume until it sounds good.
EDIT:
I added more details than required so this might also help other TBer's as well.
