Let it Rip....
06-23-2004 | 06:18 AM
#3
I had plenty of power when I just had 75 watts going to each side for a 2 way set up.
Now I have 150 per side but its a 3 way front end...still plenty of power.
Today im going to be going active... I will have 4 channels of 75 watts to the midrange and tweets and 150 per midbase.
Both ways sound equally loud heh.
[ June 23, 2004, 07:19 AM: Message edited by: AAAAAAA ]
Now I have 150 per side but its a 3 way front end...still plenty of power.
Today im going to be going active... I will have 4 channels of 75 watts to the midrange and tweets and 150 per midbase.
Both ways sound equally loud heh.
[ June 23, 2004, 07:19 AM: Message edited by: AAAAAAA ]
06-23-2004 | 08:49 AM
#5
My Avenger had around 400 watts to the front end, and 450 to the sub. All-active rocks 
Interestingly, my Daytona had only 150 watts to the front, passively crossed (both 3-way setups) and the it sounded about as loud. I haven't been able to find an exact answer on the theory that if you have a 75x2 amp and divide it's power through the passive crossover 3-ways, does each speaker get 75 watts? If so, the power seen by the speakers should be the same as if you had 3 75x2 amps crossed actively.
Interestingly, my Daytona had only 150 watts to the front, passively crossed (both 3-way setups) and the it sounded about as loud. I haven't been able to find an exact answer on the theory that if you have a 75x2 amp and divide it's power through the passive crossover 3-ways, does each speaker get 75 watts? If so, the power seen by the speakers should be the same as if you had 3 75x2 amps crossed actively.
06-23-2004 | 09:10 AM
#7
Thread Starter
1000 Watt CAFz'r
Joined: Oct 2003
Posts: 1,783
I'll try to answer your question SUX 2BU.
If you had an amplifier that output a 100hz sine wave. At the top of the wave it measures +5 volts and at the bottom of the wave it measures -5 volts. Reproducing another frequency in addition to the 100 hz tone would modulate the existing sine wave to exceed the +/- 5 volt swings. For example, what if you had a 100hz positive peak in addition to a 500hz positive peak both requiring a simultanious +5 volt swing. To reproduce this cleanly you'd need to be able to produce a +/- 10 volt swing.
Actively filtering frequencies before the amplification stage gives you more peak headroom when reproducing multiple tones at the same time. (Music for example is multiple frequencies at the same time) By playing the 100hz tone and 500hz tone on separate amplifiers, each sine wave can be fully reproduced by a +/-5 volt amp. Flipping this over to watts, putting a separate 75 watt/ch amp on your mids and tweeters allows the tweeter's output to be unaffected by midrange dynamic clipping.
How often does dynamic clipping occur? Probably a lot more than most people think. It is very common to have 20db fluctuations in most popular music these days. If you want proof, go purchase the Radio Shack digital SPL meter. It has minimum and maximum readings as well as peak hold. This should give you a good idea how much power a system really requires. Run your system using the meter to find an average SPL level of 85db. Now set the meter up to measure peaks in some favourite dynamic music and take note of this. Now raise the level to 95 db average and see if the difference from peak SPL to the 95 db average level stays the same. If the difference is less, there is a very good chance that you have pushed your amps into clipping. In other words, you have run out of dynamic headroom.
Playing a 100hz tone on a 100 watt passively crossed over 2 way system will play just as loud as an actively crossed over system. With music however, multiple frequencies have greater headroom when an active cross over is used.
I hope I made sense to some of you.
Adam
[ June 23, 2004, 10:36 AM: Message edited by: PEI330Ci ]
If you had an amplifier that output a 100hz sine wave. At the top of the wave it measures +5 volts and at the bottom of the wave it measures -5 volts. Reproducing another frequency in addition to the 100 hz tone would modulate the existing sine wave to exceed the +/- 5 volt swings. For example, what if you had a 100hz positive peak in addition to a 500hz positive peak both requiring a simultanious +5 volt swing. To reproduce this cleanly you'd need to be able to produce a +/- 10 volt swing.
Actively filtering frequencies before the amplification stage gives you more peak headroom when reproducing multiple tones at the same time. (Music for example is multiple frequencies at the same time) By playing the 100hz tone and 500hz tone on separate amplifiers, each sine wave can be fully reproduced by a +/-5 volt amp. Flipping this over to watts, putting a separate 75 watt/ch amp on your mids and tweeters allows the tweeter's output to be unaffected by midrange dynamic clipping.
How often does dynamic clipping occur? Probably a lot more than most people think. It is very common to have 20db fluctuations in most popular music these days. If you want proof, go purchase the Radio Shack digital SPL meter. It has minimum and maximum readings as well as peak hold. This should give you a good idea how much power a system really requires. Run your system using the meter to find an average SPL level of 85db. Now set the meter up to measure peaks in some favourite dynamic music and take note of this. Now raise the level to 95 db average and see if the difference from peak SPL to the 95 db average level stays the same. If the difference is less, there is a very good chance that you have pushed your amps into clipping. In other words, you have run out of dynamic headroom.
Playing a 100hz tone on a 100 watt passively crossed over 2 way system will play just as loud as an actively crossed over system. With music however, multiple frequencies have greater headroom when an active cross over is used.
I hope I made sense to some of you.
Adam
[ June 23, 2004, 10:36 AM: Message edited by: PEI330Ci ]
06-23-2004 | 09:24 AM
#8
50 Watt CAFz'r
Joined: Jan 2004
Posts: 206
Never enough.....lol
My Honda Civic used 3 MTX 240's (20X2)
The car used Veritas Mids (4ohm)and Veritas horns (16 ohm), and two MTX Black Gold 12's (8 ohm is series...yes series)
So basically I had very low power. And the car did 144 spl with the IASCA disk, and the top end could rip your head off it I needed to do so. The car used very efficent drivers in some really well built enclosures, in the rigth locations for that car.
My rule of thumbs for building comp cars is the more the better. I'm not going to use it all, but I have it if I need it.
This helps with dynamic head room. Lets say to get the volume you want, it takes 90% of you amp power. And in a song a very dynamic section comes in (like a trumpet blast) that will require 30% more power to accuratly achieve. You don't have that extra 20% so you end up with a poor reproduction.
If I use an amplifier at 40% I have alot of room to play with .
Also under powering can blow drivers as much as over powering. To get volume and you crank the amp to its max it may start sending out clip signals, which to a speaker is intermitant DC, which burns up Voice coils.
basic guildline i use is take what they tell you the speaker can handle and at least go 50% more.
But then again I'm building to very specific musical taste (the IASCA disk) so you need to be carefull.
My Impala (due out this summer) uses 100w on each tweet, and each mid, and 1000w on the ten inch sub in the dash. Not to get loud, but to have that dynamic capability.
My Honda Civic used 3 MTX 240's (20X2)
The car used Veritas Mids (4ohm)and Veritas horns (16 ohm), and two MTX Black Gold 12's (8 ohm is series...yes series)
So basically I had very low power. And the car did 144 spl with the IASCA disk, and the top end could rip your head off it I needed to do so. The car used very efficent drivers in some really well built enclosures, in the rigth locations for that car.
My rule of thumbs for building comp cars is the more the better. I'm not going to use it all, but I have it if I need it.
This helps with dynamic head room. Lets say to get the volume you want, it takes 90% of you amp power. And in a song a very dynamic section comes in (like a trumpet blast) that will require 30% more power to accuratly achieve. You don't have that extra 20% so you end up with a poor reproduction.
If I use an amplifier at 40% I have alot of room to play with .
Also under powering can blow drivers as much as over powering. To get volume and you crank the amp to its max it may start sending out clip signals, which to a speaker is intermitant DC, which burns up Voice coils.
basic guildline i use is take what they tell you the speaker can handle and at least go 50% more.
But then again I'm building to very specific musical taste (the IASCA disk) so you need to be carefull.
My Impala (due out this summer) uses 100w on each tweet, and each mid, and 1000w on the ten inch sub in the dash. Not to get loud, but to have that dynamic capability.
06-23-2004 | 09:32 AM
#10
Guest
Posts: n/a
Originally posted by SUX 2BU:
My Avenger had around 400 watts to the front end, and 450 to the sub. All-active rocks Interestingly, my Daytona had only 150 watts to the front, passively crossed (both 3-way setups) and the it sounded about as loud. I haven't been able to find an exact answer on the theory that if you have a 75x2 amp and divide it's power through the passive crossover 3-ways, does each speaker get 75 watts? If so, the power seen by the speakers should be the same as if you had 3 75x2 amps crossed actively.
My Avenger had around 400 watts to the front end, and 450 to the sub. All-active rocks
Interestingly, my Daytona had only 150 watts to the front, passively crossed (both 3-way setups) and the it sounded about as loud. I haven't been able to find an exact answer on the theory that if you have a 75x2 amp and divide it's power through the passive crossover 3-ways, does each speaker get 75 watts? If so, the power seen by the speakers should be the same as if you had 3 75x2 amps crossed actively.
