575 watt head w/ 810 cab?

[Mr. Foxen]

[quote name='Grambo' post='807561' date='Apr 15 2010, 08:08 PM']+1
I run an EVO III 500 with 1X ABM 210T which is great for practice, 1X 410T which is good for most mid sized venues, and both cabs if I want to get stupidly loud!
The cabs are 8 Ohm each, so running both not only moves a great deal of air, but drives the amp at maximum output.

I find the setup does everything I want [/quote]

Does mean one of your cabs is running at half power though.

[Conan]

[quote name='Prime_BASS' post='804601' date='Apr 13 2010, 09:52 AM']But yes assuming ohmage is matched and the 8x10 isn't rated too high it'll be fine.[/quote]

I'm getting confused myself now...

I thought that the "power handling rating" on a cabinet indicated how much output it could safely cope with without risk of damaging the speakers? As far as I am aware, no cab displays a "minimum power recommendation" in order to drive it efficiently!

So, as I see it, a 575 watt amp (bearing in mind that there seems to be an opinion that Ashdown are fairly conservative with their output claims) into an 8x10 should work perfectly fine - although technically the cab is capable of handling even more output than that! Depends on your EQ settings to a certain extent I suppose, with more bass in your sound you may find that the speakers encounter problems earlier....

[Conan]

[quote name='Mr. Foxen' post='807567' date='Apr 15 2010, 08:13 PM']Does mean one of your cabs is running at half power though.[/quote]

Is that a bad thing? Or does it just mean that the two cabs will sound slightly different as the speakers are moving further in the 2x10 than they are in the 4x10?

[Mr. Foxen]

[quote name='Conan' post='807665' date='Apr 15 2010, 09:21 PM']Is that a bad thing? Or does it just mean that the two cabs will sound slightly different as the speakers are moving further in the 2x10 than they are in the 4x10?[/quote]

Well, the 2x10 will start to clip when the 4x10 is cruising, so you limit your clean power to twice that of the 2x10. Effectively, you are lugging 2 extra speakers for no gain, and don't have the recommended vertical stack option.

[andy67]

My 220w Trace all valve V4 runs my Ampeg 810e (800 @ 4ohms) perfectly.

andy

[Grambo]

[quote name='Mr. Foxen' post='807567' date='Apr 15 2010, 08:13 PM']Does mean one of your cabs is running at half power though.[/quote]
It means that more surface area moves more air - four 10" speakers will obviously have an advantage over two 10" speakers due to their surface area, though they absorb more "power", they offer less resistance to the amp.

Speakers don't have "power" as such - they react to the amount of energy fed to them, which they handle according to the limitations of their electrical capability (power handling - so the coils don't melt) and the amount of physical movement they are capable of generating in the air. To put it (over) simply - the amp will generate it's output according to how much it has to work. Two 8 Ohm cabs will give it a resistance of 4 Ohms to work with, which makes it work better. I don't think it is particularly helpful to worry about which cab is absorbing more power - if one is less electrically efficient than another as a result of the particular way they are configured then so be it, that's life! We haven't even touched on wiring schemes (series/parallel etc.) - it makes my brain hurt :wacko:

Who started this anyway.......

[Mr. Foxen]

[quote name='Grambo' post='807751' date='Apr 15 2010, 10:28 PM']It means that more surface area moves more air - four 10" speakers will obviously have an advantage over two 10" speakers due to their surface area, though they absorb more "power", they offer less resistance to the amp.

Speakers don't have "power" as such - they react to the amount of energy fed to them, which they handle according to the limitations of their electrical capability (power handling - so the coils don't melt) and the amount of physical movement they are capable of generating in the air. To put it (over) simply - the amp will generate it's output according to how much it has to work. Two 8 Ohm cabs will give it a resistance of 4 Ohms to work with, which makes it work better. I don't think it is particularly helpful to worry about which cab is absorbing more power - if one is less electrically efficient than another as a result of the particular way they are configured then so be it, that's life! We haven't even touched on wiring schemes (series/parallel etc.) - it makes my brain hurt :wacko:

Who started this anyway.......[/quote]

The problem is each cab receives the same power due to the same impedance (not resistance), but the one with 4 speakers spreads it over all 4, whereas the other only to two. So the two will be reaching their excursion limit at half the power of the 4x10. The 4x10 will be louder due to better coupling with the air, and possibly drown out the sound of the protesting 2x10, risking a breakage. Better having a 16ohm 2x10, making a 6x10 with all speakers working the same, at 5.3 ohm, or two cabs the same.

[Grambo]

[quote name='Mr. Foxen' post='807767' date='Apr 15 2010, 10:37 PM']The problem is each cab receives the same power due to the same impedance (not resistance), but the one with 4 speakers spreads it over all 4, whereas the other only to two. So the two will be reaching their excursion limit at half the power of the 4x10. The 4x10 will be louder due to better coupling with the air, and possibly drown out the sound of the protesting 2x10, risking a breakage. Better having a 16ohm 2x10, making a 6x10 with all speakers working the same, at 5.3 ohm, or two cabs the same.[/quote]
All absolutely reasonable, of course (and I regret the mis-use of the term "resistance") but my set up works well for me, I don't notice much in the way of problems with the 2X10 when coupled with the 4X10. All I can say is that it works, is flexible, and possibly cheaper/easier than sourcing a 2X10 @ 16 Ohms (which may lead to other issues when used on it's own) In a perfect world, I guess we would all employ the best possible combination of gear based on performance alone, but life tends to impose restrictions.....

[Phil Starr]

[quote name='Mr. Foxen' post='807767' date='Apr 15 2010, 10:37 PM']The problem is each cab receives the same power due to the same impedance (not resistance), but the one with 4 speakers spreads it over all 4, whereas the other only to two. So the two will be reaching their excursion limit at half the power of the 4x10. The 4x10 will be louder due to better coupling with the air, and possibly drown out the sound of the protesting 2x10, risking a breakage. Better having a 16ohm 2x10, making a 6x10 with all speakers working the same, at 5.3 ohm, or two cabs the same.[/quote]

this is one way of looking at it. if your 2x10 will handle the full output of the Ashdown now it will go on handling it whatever else you add in parallel. The amp is limited by its rail voltage (100v) which it can't go past. Adding more speakers will draw extra current from the amp and if the overall impedance drops below 4 ohms you could damage the amp but if the 2x10 can handle the amp then they will not be damaged.



If you use speakers with different impedances then the one with the lowest impedance will draw more power. If the speakers are the same then doubling the surface area will increase the sound level by 3dB. An 8x10 with the same speakers will increase the sound by 6dB over a 2x10 even though the impedance and the power used is the same. This will have the same effect as using four times the amplifier power though it will not be four times louder because of the way our ears work. It will be significantly louder though.



If you want to go down the route of a 2x10 and a 4x10 then give us the impedances and we can tell you what will happen.