Speaker ohm

[Triumphman]

Quick refresher needed.
If my amp is requesting an 8 ohm minimum speaker, what are the options?
Iirc there’s a formula, 2 x 16 ohm in series would also work etc that’s probably wrong but you get my drift

[Skybone]

2x 16 Ohm loads create an 8 Ohm load.
2x 8 Ohm loads create a 4 Ohm load.
Etc.

You can't mix 'n' match cab impedance loads, ie, a 16 Ohm cab and a 8 Ohm cab together.

[xgsjx]

Either series or parallel is gonna be fine.
2 16 ohm in series would be fine too, as that would be 32 ohm, but not many people want to do that.

Edited October 29, 2017 by xgsjx

[crez5150]

[quote name='Skybone' timestamp='1509113475' post='3396740']
2x 16 Ohm loads create an 8 Ohm load.
2x 8 Ohm loads create a 4 Ohm load.
Etc.

You can't mix 'n' match cab impedance loads, ie, a 16 Ohm cab and a 8 Ohm cab together.
[/quote]

Not strictly true... you can but you get missmatched loads

[xgsjx]

[quote name='crez5150' timestamp='1509114047' post='3396749']
Not strictly true... you can but you get missmatched loads
[/quote]
Which it would actually make sense to use different ohm cabs if the cabs were different. E.G. a 16 ohm 2x10 with an 8 ohm 4x10. This way all the drivers are getting the same from the amp.
Whereas if you were to use a 2x10 & 4x10 that were both 8 ohm, the 2 10s in one cab would be getting the same power as the other 4 in the other cab.

[Dad3353]

[quote name='Triumphman' timestamp='1509112611' post='3396730']
Quick refresher needed.
If my amp is requesting an 8 ohm minimum speaker, what are the options?
Iirc there's a formula, 2 x 16 ohm in series would also work etc that's probably wrong but you get my drift
[/quote]
[quote name='xgsjx' timestamp='1509113801' post='3396745']
Either series or parallel is gonna be fine.
2 16 ohm in parallel would be fine too, as that would be 32 ohm, but not many people want to do that.
[/quote]

For clarity, there are basically two formulae...

Speakers in parallel: divide the impedance. Example: 2 x 16 in parallel show 8 to the amp, 4 x 16 in parallel show 4 to the amp.

Speakers in series: addition the impedance. Example: 2 x 16 in series show 32 to the amp. 4 x 4 show 16 to the amp.

That's the simple stuff; mixing impedances in parallel can become messy, so I'll leave that. Mixing impedances in series just means adding 'em up.
Hope this helps.

Edited October 27, 2017 by Dad3353

[chris_b]

16 ohm and 8 ohm cabs equal 5.3ohms so can be handled by any SS or D Class amp.

The 16 ohm cab will see 33% of the power and the 8 ohm cab will see 66% of the power.

[TheGreek]

Shouldn't this type of thread be pinned?

[thepurpleblob]

Note that wiring speakers in series as separate cabs requires weird cables and is not common. You should generally avoid having lots of different speakers as it can create odd interference patterns - especially at low frequencies.

[xgsjx]

[quote name='TheGreek' timestamp='1509125208' post='3396883']
Shouldn't this type of thread be pinned?
[/quote]
You'll find this type of thread in the "Amps & Cabs" section. I thought there was something similar pinned there.

Just checked & it's the top pin.

http://basschat.co.uk/topic/135-impedance-etc/

Edited October 29, 2017 by xgsjx

[machinehead]

[quote name='xgsjx' timestamp='1509113801' post='3396745']
Either series or parallel is gonna be fine.
2 16 ohm in parallel would be fine too, as that would be 32 ohm, but not many people want to do that.
[/quote]

Just in case someone reads this in isolation and not to be a clever dick... but 2 16 ohm in parallel would be [b][i]8 ohm[/i][/b] - not 32 ohm as stated. 2 16 ohm in [b][i]series[/i][/b] would be 32 ohm.

Probably just a typo though.

Frank.

[xgsjx]

[quote name='machinehead' timestamp='1509276490' post='3397696']
Just in case someone reads this in isolation and not to be a clever dick... but 2 16 ohm in parallel would be [b][i]8 ohm[/i][/b] - not 32 ohm as stated. 2 16 ohm in [b][i]series[/i][/b] would be 32 ohm.

Probably just a typo though.

Frank.
[/quote]
Yup, I was trying to post while I was at work & just as I started the post, it got busy.
I meant to go back & correct it, but forgot all about it. I’ll go do that now.