Speaker and amp combination

[teebone 0]

Hi

 

If I bought an amp capable of kicking out 1200w then got 2x 300w speakers and 2x 600w speakers would that be compatible for use with the amp?

Thanks

 

[spinner 0]

QUOTE (teebone @ Dec 9 2005, 04:23 PM)

Hi If I bought an amp capable of kicking out 1200w then got 2x 300w speakers and 2x 600w speakers would that be compatible for use with the amp? Thanks

Do you mean an amp producing 1200 wpc or 600 wpc and do you mean into 4 ohms in each case?

[teebone 0]

Sorry what I meant to say is I would like to 1st get two speakers @ 300w each and then later on get another two. So would I be looking for an amp that has 4 channels and has a total power of 1200w?

 

Would I be able to safely use just the 1 st two speakers at first. I presume an amp would allocate the correct wattage to each channel?

 

Spot the novice!

 

Thanks

 

[spinner 0]

QUOTE (teebone @ Dec 9 2005, 08:26 PM)

Sorry what I meant to say is I would like to 1st get two speakers @ 300w each and then later on get another two. So would I be looking for an amp that has 4 channels and has a total power of 1200w? Would I be able to safely use just the 1 st two speakers at first. I presume an amp would allocate the correct wattage to each channel? Spot the novice! Thanks

No. You'd be looking for an amp that produces 600 watts per channel ( 2 channels ) into 4 ohms. It will produce 300 watts per channel into 8 ohms.

 

Most speaker cabinets are 8 ohms resistance so if you started with 2 x 300 watt cabinets

you would have an output of 300 watts per channel. By adding another 8 ohm cabinet to each channel you will double the output to 600 watts per channel.

 

When choosing your cabinets look for the highest sensitivity you can afford. For every 3db of extra sensitivity a speaker will ( nominally ) be twice as loud.

 

As an example, I have seen some budget "Funky" speakers with a sensitivity of 94db ( not very good ) whereas the average pro speaker will have a sensitivity around 98db or more.

 

As far as the safety aspect is concerned don't use the full output of your amp with the 2 300 watt speakers. It's always a good idea to have a bit of headroom and having it up too high might induce clipping, which could damage the cones.

 

Hope that helps.

[norty303 0]

QUOTE

For every 3db of extra sensitivity a speaker will ( nominally ) be twice as loud.

 

3db is normally what they term as being the amount the level has to increase for it to be perceivably louder. In order to achieve this you will need to input at least twice the power (twice the power will not actually yield 3db increase due to the losses from heat/power compression) So if you can get a speaker with 3db higher sensitivity you will need to drive with half the power to achieve the same results.

 

Many pro-audio speakers run 106db sensitivity through the use of horn loading. These will achieve levels you simply wouldn't achieve regardless of input power from a regular reflex loading. Horns also benefit from horn mouth coupling when used in multiples which in turn gains extra 'free' db's.

 

For sound to be perceived as twice as loud you need 10 times the power.