Passive Speakers

[MisterJames]

Hey Guys (and girls)

 

So ive got x4 DAP RW15 at 240rms 8ohms and I would like to know is it better to have to seperate amplifiers matching there wattage or just one powerful say 530wattrms amp powering all 4? Or is their going to be unequal powering going to the speakers (IE: One gets more then the other?)

 

I Seem to think that if I do that then ill be damaging one set of speakers :/

 

Btw the speakers are full range!

Amp would P1200 by DAP and seperate ones are P700 DAP Again at 240wrms Perfect match!

 

Cheers

 

James

[ACIDMAN]

In an ideal world it is best to match the rms output of your amp to the program rating of your speakers at their nominal load,ie 240w rms speaker @ 8ohms will be 480w program. Therefore your amp should be able to deliver 480w rms @ 8ohms p/ch.

If you have two 8ohm speakers per side (assuming they are wired in parallel,which most are)the nominal load becomes 4ohms. Therefore you would need an amp capable of delivering

960w p/ch @ 4ohms. This will give your amp plenty of headroom and if there is any distortion it will be the speakers and not your amp.

You can run an amp equal to the rms rating of your speakers, as a lot of people do,but this is a minimum requirement as long as your not running the rig too hard.

[sleah]

Acidman, we try to stick to RMS values where possible here as 'program', 'peak', 'music power' are often missleading terms and more often made up numbers! Sometimes it is as you use double the RMS sometimes it's x 0.775 sometimes it's litterally pulled from the air :(

 

The OP has speakers 240wRMS @ 8ohms. A single amp delivering 500wRMS in to 4ohms per chanel would be well matched where the speakers are paired up: i.e. 2 per chanel.

Or 2 amps delivering 240wRMS into 8ohms per chanel to allow an amp chanel per speaker. Either is perfectly acceptable, it is up to personal choice which ever way you go.

Two amps gives you redundancy if one fails you carry on with two speakers :) also flexibility in that you could add more speakers as almost all amps can drive down to 4ohms or lower.

If budget and space are a consideration then go for one amp, a decent quality at that. If an amp isn't overdriven or physically abused it will give years of service, it's actually quite rare for an amp to fail compared to say a CD player or even a mixer that have moving parts to fail.

 

HTH a bit :unsure:

[ACIDMAN]

Sorry ! In answer to your question you would do better running the 1200 amp with two speakers per side(600w rms p/ch @ 4ohms) than two of the 700's with one speaker per side each(240w rms p/ch @ 8ohms). This will give each channel a bit more room to breathe !

[MisterJames]

Sleah! That help alot! Cheers...

 

Im not on budget and space is never a problem and shouldnt be in my opinion! So really two amplifiers at 240wrms 8ohms is perfect for the speakers! Smashing!

 

A quick question? Ive got a Dap System... so is it logical to buy DAP amplifiers or can you recommend something that better? for a good price?

 

Cheers

 

James

 

A concurrent post has been automatically merged from this point on.

 

Sorry ! In answer to your question you would do better running the 1200 amp with two speakers per side(600w rms p/ch @ 4ohms) than two of the 700's with one speaker per side each(240w rms p/ch @ 8ohms). This will give each channel a bit more room to breathe !

 

 

Hummm.. I see your point but as sleah said if that amplifier goes im stuffed so I probably would get two seperate amps... But would you recommend getting amplifers that are abit powerfuller? Ive been told by a guy where I used to work that its always best to have amplifiers that are less powerful than what the speaker can do to revent damage to the speakers? Then again surely youd be damaging the amp? Im in pickle with that!

 

Cheers and thanks for the advice. its well noted!

 

James

[ACIDMAN]

I must agree with Sleah, any rms,programme or peak power values must be taken with a little pinch of salt . Some manufactures test with 1/8 pink noise for half an hour,although this lacks in dynamics,and others max power for 8 hours with very dynamic music. All I was trying to say is that it is always better to have more power available from your amp than JUST enough or indeed not enough. Have seen what happens to a 100w amp at full tilt on a couple of 1000w speakers ? Hot....Hotter.......BANG !

[MisterJames]

** laughs out loud **... Your example of hot hotter bang... is well expressed.

 

The question is with 240wattrms speakers what is the best breathing space? 100watt extra? Or doesnt it matter? And if you do need a couple more watts do you need alot more spare with Subwoofers? seen as alot of power/energy is lost moving the 18" bass driver if ive been told correct? so does there need to be a extra 200watt spare or is extra 50w okie? the subwoofers are again DAP 300wrms 18" drivers 8ohms

 

And is it best to buy DAP amplifiers to match the DAP speakers?

[TonyMitchell]

The question is with 240wattrms speakers what is the best breathing space? 100watt extra?

 

When matching an amplifier to cabs, go for one that can deliver between 1.5 and 2.0 times the RMS of the load. You wouldn't buy a car with a top speed of 70mph for motorway driving :)

 

And if you do need a couple more watts do you need alot more spare with Subwoofers?

 

What do you mean by "need a couple more watts"?

 

And is it best to buy DAP amplifiers to match the DAP speakers?

 

There is no need to, any suitably matched amplifier should do the job. Having said that, there's little point in buying a Gruppen et al to run a pair of firmly budget-camp boxes and I guess you could do worse than keep it in the DAP family so to speak.

 

You'll only encounter the requirement for proprietory amplification & processing at a much higher level within pro audio.

[ACIDMAN]

The rms value of your average torroidal amp is probably worked out with a single sine wave assuming it is 100% efficient. Most amps are only 60-70% efficient as the rest of the power is dissipated as heat (unless it is a switch mode amp and they can be 95% efficient). So with a MUSIC source and not a single SINE WAVE the amp will produce even less power. And if you don't have spare power in the amp it will run even harder and so hotter and be even less efficient. So if you aim for an amp capable of the PROGRAMME power of the speakers,NOT to be confused with the rubbishy made up PEAK POWER,this more than makes up for the 30-40% inefficiency of the amp.

[sleah]

The whole business of having a more powerful amp than speakers is a very split debate.

Everyone agrees the amp should never be less power than the speakers attached, unless it's a "quick fix temporary setup I can't lay my hands on anything else for this gig" type situation :)

 

A more powerful amp does indeed give more headroom, and speakers can often handle more than their rated power for short periods, providing it is a nice clean signal with no distortion or clipping.

But in a dry hire or DJ situation there is an element of risk of them being driven too hard for too long - but again a DJ will drive an amp into clipping whatever (well some will!) which will cause damage however your system is matched.

 

Personally I go for amp matched to speakers as in my previous post. I use the clip lights on the amps (not the mixer :( ) as a guide. I know (with my kit) I can just clip the LEDs and everything is fine. I like the visual indication that I'm at the limit.

 

With a good budget then you can go for quality kit, that's what matters. Cheap kit will let you down and won't have the same amount of headroom built in and the quoted figures are often missleading.

Just think of the boy racer telling you about the 1200w amp in his car thats obviously 200w more powerful than your 1k PA rig. Yeah right!

 

 

I'm sure more experienced folk will be along to give you more advice soon :unsure:

[ACIDMAN]

If a roady can carry one speaker across a room and he is a little tired and hot the give him 4 speakers to carry and see if he gets hotter and goes bang !!!

[MisterJames]

The question is with 240wattrms speakers what is the best breathing space? 100watt extra?

 

When matching an amplifier to cabs, go for one that can deliver between 1.5 and 2.0 times the RMS of the load. You wouldn't buy a car with a top speed of 70mph for motorway driving :)

 

And if you do need a couple more watts do you need alot more spare with Subwoofers?

 

What do you mean by "need a couple more watts"?

 

And is it best to buy DAP amplifiers to match the DAP speakers?

 

There is no need to, any suitably matched amplifier should do the job. Having said that, there's little point in buying a Gruppen et al to run a pair of firmly budget-camp boxes and I guess you could do worse than keep it in the DAP family so to speak.

 

You'll only encounter the requirement for proprietory amplification & processing at a much higher level within pro audio.

 

 

 

 

" I guess you could do worse than keep it in the DAP family so to speak." Haha are you saying DAP isnt the best product for sound as ive heard there a good kit?

[TonyMitchell]

" I guess you could do worse than keep it in the DAP family so to speak." Haha are you saying DAP isnt the best product for sound as ive heard there a good kit?

 

I commented that this particular manufacturer produces budget end boxes. I can't recall ever hearing any, so I can't say what they sound like. However, I can safely say they are most certainly not "the best product for sound" - boxes that fit in that category cost thousands of pounds each.

 

I was also trying to illustrate the merits of buying an amplifier at a similar level, as unless you have a significant upgrade/expansion plan in the forseeable future, it seems pointless to blow a couple of grand on a professional power amp to run a few cheap disco-type speakers.

[themadhippy]

If a roady can carry one speaker across a room and he is a little tired and hot

Its time to get a new roadie