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What kind of amp


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#1 trutrinivirus

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Posted 27 April 2005 - 12:12 PM

I got 2 peavey pv115 speakers and I am thinking about getting the XLS 402. Would that me enough power to run those 2 speakers... I would be basically doing house parties. Thanks

#2 DGlass

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Posted 27 April 2005 - 01:39 PM

I went to the Peavey Web site and got their power specs for your speakers. They are rated at 8 ohms, 400 watt Program/800 watt peak.

The XLs402 would be slightly underpowered with its 260watt/8 ohm per channel rating.

There are "basically" three power ratings that can be given to a loudspeaker speaker and without going into a long technical description of each they are Continuous Power, Program Power and Peak Power. It is the generally excepted practice in the Pro Audio industry to have an amplifier that is at least twice (2x) the Continuous power rating of the speaker load at the given loudspeakers impedance (Program Power in most cases will be twice the Continuous Power). This will give you 3db of headroom in the amplifier for peaks in the signal source. If an amplifier is being pushed to full output and then you get a peak in the signal source an amplifier can go into clipping. This clipped signal looks like DC, or alternating DC in some cases, to the speaker causing the cone to go all the way out at full power or all the way the way in at full power. This can cause burning of the voice coil as it tries to dissipate all the power through just a few windings. A speaker is better adapted to handle short durations of higher power (thus their peak rating) then it is to handle full power at longer steady state durations (DC). High power DC can burn out a speaker very quickly. If you have an amplifier that matches, or is close to, the speaker manufactures continuous power rating than you will have little to no headroom in the system for peaks. It's better to have an amplifier that is larger rather than smaller-but then again not to big.  

I like to also use the. 8/1.25 rules (guidelines) for selecting an amplifier. This says that you should look for an amplifier that has a power rating that falls into the range of .8 to 1.25 times the Program Power rating of the speaker for the given impedance.
For example using your speaker load that is rated for 400 watts Program at 8 ohms I would be looking for an amplifier that can do between 320 watts and 500 watts.

400 watts for 3db of headroom.
400 watts x .8 = 320 watts
400 watts x 1.25= 500 watts

In this case I would use an amplifier of around 500 watts, if I was doing hard rock and roll all the time, for the extra headroom. If I was doing voice, soft dance music or soft music all the time I could get away using an amplifier with about 320 watts. Remember if I use an amplifier that is significantly below the twice power rule I will give up headroom for signal peaks. Although this gives me a range I try to select an amplifier that is close to twice the Continuous Power rating or equal to the Program Power. In your casethat would be 400 watts at 8 ohms. This way I am pretty much safe doing almost anything.

The twice power rule is an easy way to calculate amplifier power need since 3db is 2 times the Continuous Power rating of the speakers or pretty close to the Program power rating and the. 8/1.25 guideline-rule gives me an amplifier output range to look for.

The next thing to do is select an amplifier model with the features you desire that's within your price range.

In this power range of 320 watts to 500 watts, 8 ohms we have the:

XLS602    370 watts/channel
Xs500      400 watts/channel
Xs700      450 watts/channel
CE2000    400 watts/channel
K1           350 watts/channel
K2           500 watts/channel

#3 bigdaddyajay

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Posted 28 August 2005 - 10:34 AM

QUOTE(DGlass @ Apr 27 2005, 01:39 PM)
I went to the Peavey Web site and got their power specs for your speakers. They are rated at 8 ohms, 400 watt Program/800 watt peak.

The XLs402 would be slightly underpowered with its 260watt/8 ohm per channel rating.

There are "basically" three power ratings that can be given to a loudspeaker speaker and without going into a long technical description of each they are Continuous Power, Program Power and Peak Power. It is the generally excepted practice in the Pro Audio industry to have an amplifier that is at least twice (2x) the Continuous power rating of the speaker load at the given loudspeakers impedance (Program Power in most cases will be twice the Continuous Power). This will give you 3db of headroom in the amplifier for peaks in the signal source. If an amplifier is being pushed to full output and then you get a peak in the signal source an amplifier can go into clipping. This clipped signal looks like DC, or alternating DC in some cases, to the speaker causing the cone to go all the way out at full power or all the way the way in at full power. This can cause burning of the voice coil as it tries to dissipate all the power through just a few windings. A speaker is better adapted to handle short durations of higher power (thus their peak rating) then it is to handle full power at longer steady state durations (DC). High power DC can burn out a speaker very quickly. If you have an amplifier that matches, or is close to, the speaker manufactures continuous power rating than you will have little to no headroom in the system for peaks. It's better to have an amplifier that is larger rather than smaller-but then again not to big. 

I like to also use the. 8/1.25 rules (guidelines) for selecting an amplifier. This says that you should look for an amplifier that has a power rating that falls into the range of .8 to 1.25 times twice the Continuous Power rating of the speaker for the given impedance.
For example using your speaker load that is rated for 400 watts Program at 8 ohms I would be looking for an amplifier that can do between 320 watts and 500 watts.

400 watts for 3db of headroom.
400 watts x .8 = 320 watts
400 watts x 1.25= 500 watts

In this case I would use an amplifier of around 500 watts, if I was doing hard rock and roll all the time, for the extra headroom. If I was doing voice, soft dance music or soft music all the time I could get away using an amplifier with about 320 watts. Remember if I use an amplifier that is significantly below the twice power rule I will give up headroom for signal peaks. Although this gives me a range I try to select an amplifier that is close to twice the Continuous Power rating or equal to the Program Power. In your casethat would be 400 watts at 8 ohms. This way I am pretty much safe doing almost anything.

The twice power rule is an easy way to calculate amplifier power need since 3db is 2 times the Continuous Power rating of the speakers or pretty close to the Program power rating and the. 8/1.25 guideline-rule gives me an amplifier output range to look for.

The next thing to do is select an amplifier model with the features you desire that's within your price range.

In this power range of 320 watts to 500 watts, 8 ohms we have the:

XLS602    370 watts/channel
Xs500      400 watts/channel
Xs700      450 watts/channel
CE2000    400 watts/channel
K1           350 watts/channel
K2           500 watts/channel
View Post



What is you're using 2 speakers per channel?  In the above example would you just double everything.  With 2 400W speakers per channel at 8ohms, would you need a 800W per channel amp?
Thanks

#4 DGlass

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Posted 30 August 2005 - 10:40 AM

QUOTE(bigdaddyajay @ Aug 28 2005, 10:34 AM)
QUOTE(DGlass @ Apr 27 2005, 01:39 PM)
I went to the Peavey Web site and got their power specs for your speakers. They are rated at 8 ohms, 400 watt Program/800 watt peak.

The XLs402 would be slightly underpowered with its 260watt/8 ohm per channel rating.

There are "basically" three power ratings that can be given to a loudspeaker speaker and without going into a long technical description of each they are Continuous Power, Program Power and Peak Power. It is the generally excepted practice in the Pro Audio industry to have an amplifier that is at least twice (2x) the Continuous power rating of the speaker load at the given loudspeakers impedance (Program Power in most cases will be twice the Continuous Power). This will give you 3db of headroom in the amplifier for peaks in the signal source. If an amplifier is being pushed to full output and then you get a peak in the signal source an amplifier can go into clipping. This clipped signal looks like DC, or alternating DC in some cases, to the speaker causing the cone to go all the way out at full power or all the way the way in at full power. This can cause burning of the voice coil as it tries to dissipate all the power through just a few windings. A speaker is better adapted to handle short durations of higher power (thus their peak rating) then it is to handle full power at longer steady state durations (DC). High power DC can burn out a speaker very quickly. If you have an amplifier that matches, or is close to, the speaker manufactures continuous power rating than you will have little to no headroom in the system for peaks. It's better to have an amplifier that is larger rather than smaller-but then again not to big. 

I like to also use the. 8/1.25 rules (guidelines) for selecting an amplifier. This says that you should look for an amplifier that has a power rating that falls into the range of .8 to 1.25 times twice the Continuous Power rating of the speaker for the given impedance.
For example using your speaker load that is rated for 400 watts Program at 8 ohms I would be looking for an amplifier that can do between 320 watts and 500 watts.

400 watts for 3db of headroom.
400 watts x .8 = 320 watts
400 watts x 1.25= 500 watts

In this case I would use an amplifier of around 500 watts, if I was doing hard rock and roll all the time, for the extra headroom. If I was doing voice, soft dance music or soft music all the time I could get away using an amplifier with about 320 watts. Remember if I use an amplifier that is significantly below the twice power rule I will give up headroom for signal peaks. Although this gives me a range I try to select an amplifier that is close to twice the Continuous Power rating or equal to the Program Power. In your casethat would be 400 watts at 8 ohms. This way I am pretty much safe doing almost anything.

The twice power rule is an easy way to calculate amplifier power need since 3db is 2 times the Continuous Power rating of the speakers or pretty close to the Program power rating and the. 8/1.25 guideline-rule gives me an amplifier output range to look for.

The next thing to do is select an amplifier model with the features you desire that's within your price range.

In this power range of 320 watts to 500 watts, 8 ohms we have the:

XLS602    370 watts/channel
Xs500      400 watts/channel
Xs700      450 watts/channel
CE2000    400 watts/channel
K1           350 watts/channel
K2           500 watts/channel
View Post



What is you're using 2 speakers per channel?  In the above example would you just double everything.  With 2 400W speakers per channel at 8ohms, would you need a 800W per channel amp?
Thanks
View Post

If you are using two speakers per side of the same impedance than you would add the power requirements and half the Impedance.
i.e. (2) 8-ohm speakers-one rated for 400 watts Program and one rated for 600 watts Program would give you a 4-ohm 1000 watt load. You would be looking for an amplifier that could do 1000 watts with a 4-ohm load for 3db of headroom in the power range of 800 watts to 1250 watts at 4-ohms. smile.gif