impedence

[warwickhunt]

[quote name='munkonthehill' post='616070' date='Oct 3 2009, 09:23 PM']i finally got a reply from H&K.

As the speaker output is wired in series you can use either a 4 ohm or an 8 ohm speaker. I would advise going for the 4 ohm option and make sure it’s rated around 200 watts. In terms of output produced, in theory it will be less because the overall impedance will have been increased but in practice it will probably sound about the same but the definition will be better as the extra speaker will share the load.

so there you go, not even the engineers can tell me what kinda output i will have....[/quote]

If you must have a figure you are probably looking at about 150w into 8 ohms but it is true the greater cone dispersion will offset the output reduction... However, extension cab in series; it's a stupid t*t of a way to do it!

[munkonthehill]

thanks for the reply dude, you have been a great help.

[munkonthehill]

ok so I have now tried my 200watt combo at a gig and it was ok but i had the amp running at full, so i have taken the plunge and bought an ashdown mag 600h woo hoo. now this runs at 575watt at 4ohms.

im picking up an ampeg 4x10hlf which is 400watt at 4ohms.

so as this is more than enough power for me im really happy and cant wait to get them and try them out, my question now is how can I get that extra 175watts of power out?

as far as i can tell is that if I run another 4ohm cab that takes my impedance to 2 ohms which will ruin my amp(not an option)

so wondering what would be the effect if i ran a 8ohm cab??

or can I in some way run 2x 4 ohm cabs in series and whats the difference running them in series rather than parallel if thats possible of course?

Edited October 17, 2009 by munkonthehill

[Mr. Foxen]

[quote name='munkonthehill' post='629146' date='Oct 17 2009, 11:07 PM']ok so I have now tried my 200watt combo at a gig and it was ok but i had the amp running at full, so i have taken the plunge and bought an ashdown mag 600h woo hoo. now this runs at 575watt at 4ohms.

im picking up an ampeg 4x10hlf which is 400watt at 4ohms.

so as this is more than enough power for me im really happy and cant wait to get them and try them out, my question now is how can I get that extra 175watts of power out?

as far as i can tell is that if I run another 4ohm cab that takes my impedance to 2 ohms which will ruin my amp(not an option)

so wondering what would be the effect if i ran a 8ohm cab??

or can I in some way run 2x 4 ohm cabs in series and whats the difference running them in series rather than parallel if thats possible of course?[/quote]

Basically, get an 8 ohm cab. Then another one.

[munkonthehill]

like a said im def getting the 4x10

i may look for 2 other cabs at 8 ohms at a later date... i also fancy a 2x10 and 1x15 rig.

[Bill Fitzmaurice]

[quote name='GreeneKing' post='613372' date='Sep 30 2009, 05:31 PM']If the amp has a max output of 200 watts or thereabout into 4 ohm, and you add an extension cab in [b]series[/b] to increase the impedance seen by the amp then the output will fall.[/quote]If the extension cab is identical the sensitivity will remain the same, as the 3dB lost to the doubled impedance will be offset by the 3dB gained via mutual coupling. In all maximum SPL will probably go up, as the fifteens typically used in combos are displacement limited to only 50 watts or so.
Running a combo at minimum impedance with the internal speaker is rare, but not unique; Eden Nemesis does so and also runs the extension speaker in series.

[Musky]

[quote name='munkonthehill' post='629146' date='Oct 17 2009, 11:07 PM']ok so I have now tried my 200watt combo at a gig and it was ok but i had the amp running at full, so i have taken the plunge and bought an ashdown mag 600h woo hoo. now this runs at 575watt at 4ohms.

im picking up an ampeg 4x10hlf which is 400watt at 4ohms.

so as this is more than enough power for me im really happy and cant wait to get them and try them out, my question now is how can I get that extra 175watts of power out?

as far as i can tell is that if I run another 4ohm cab that takes my impedance to 2 ohms which will ruin my amp(not an option)

so wondering what would be the effect if i ran a 8ohm cab??

or can I in some way run 2x 4 ohm cabs in series and whats the difference running them in series rather than parallel if thats possible of course?[/quote]

Running the MAG 600 into a 4 ohm load, the amp will be capable of knocking out it's full 575 watts if you turn it up full. Which obviously you don't want to into a cab that can only handle 400 watts. If you hear the speakers starting to make nasty noises, turn it down or back off the bottom end.

If you run a 8 ohm cab with your 4 ohm one the total impedance will be about 2.7 ohms, which will risk damaging your amp.

By running two 4 ohm cabs in series you'll be into the same scenario as adding a cab to your H+K - you'll reduce the wattage available from your amp, though you'll probably get the same sort of overall volume (though it's worth noting Bill's caveat above).

[url="http://wiki.basschat.co.uk/info:amps:impedance_and_wattage"]http://wiki.basschat.co.uk/info:amps:impedance_and_wattage[/url]

[Bill Fitzmaurice]

[quote name='Musky' post='629721' date='Oct 18 2009, 02:21 PM']Running the MAG 600 into a 4 ohm load, the amp will be capable of knocking out it's full 575 watts if you turn it up full. Which obviously you don't want to into a cab that can only handle 400 watts.[/quote]Of more significance is that most 400 watt cabs will take no more than 200 watts before farting out, so running a 4 ohm cab to 'get all my watts' is a wasted effort in the short run and the long run as well.