watts ohms power - another question

[Paul S]

I am being particularly dense here, I know, but still have trouble getting my head around this.

Taking my gear as the example. I have a Trace Elliot AH-300-12. So that is 300W at 4ohms? I have two cabs - 1153T and 2103H - both say on the back 200W 8ohm. If I use one cab, so 8 ohm, the max output of the amp would be 200W or so? 300W from both cabs? I think I get all of that. But the cabs are 200W - how can they handle this? I am confused.

I am watching an 1818X cab on eBay at the moment - apparently this is 200W 8ohms, too, so could I use this with either of the cabs I already have, even though it contains both 18" and 10" speakers?

Ta

Edited September 14, 2010 by Paul S

[Colledge]

the 300w is shared between the 2 cabs so each will get about 150w.
also power rating isn't that important, theres no harm in running an amp into cabs that can only take alot less power, aslong as you know when to turn down the volume.

[Paul S]

Right, I see. Thanks.

What would happen, theoretically, if I connected my two cabs (1x15 and 2x10) from the two outputs on the amp then daisy chained another cab? How would this affect the watts/ohms etc? Especially if only on one side like that.

[Merton]

[quote name='Paul S' post='954632' date='Sep 13 2010, 12:45 PM']Right, I see. Thanks.

What would happen, theoretically, if I connected my two cabs (1x15 and 2x10) from the two outputs on the amp then daisy chained another cab? How would this affect the watts/ohms etc? Especially if only on one side like that.[/quote]
Magic smoke. Bad idea, you'll pull the impedance down to below the amp's lowest safe rating of 4 ohms.

[flyfisher]

Assuming that the speaker connectors are all wired in parallel then the amp will 'see' 3 x 8ohm speakers = 2.66 ohms and the output power will be divided equally between all three cabs.

A handy parallel resistor calculator can be found here: [url="http://www.1728.com/resistrs.htm"]http://www.1728.com/resistrs.htm[/url]

And, as Merton has pointed out, if this is below the minimum impedance capability of the amp then beware!

Edited September 13, 2010 by flyfisher

[Hamster]

This is quite a neat little program too - [url="http://www.duncanamps.com/technical/impedance.html"]http://www.duncanamps.com/technical/impedance.html[/url]

[Paul S]

Thanks. That makes a bit more sense now. That spreadsheet is pretty clear!

So - how does the 1818x work, presumably the 18" and 10" are connected in series, and would it offer any advantages compared to a straight 1818 cab? It is heavier, for sure!

[Alien]

[quote name='Paul S' post='954696' date='Sep 13 2010, 01:22 PM']Thanks. That makes a bit more sense now. That spreadsheet is pretty clear!

So - how does the 1818x work, presumably the 18" and 10" are connected in series, and would it offer any advantages compared to a straight 1818 cab? It is heavier, for sure![/quote]

IIRC, the 1818x has a built in crossover, so the lows go to the 18" and the highs go to the 10". It'll draw somewhere around the 180-200W mark from your amp by itself, and it'll probably be damn near as loud as your other two cabs on its own.

A

[Paul S]

Thanks Alien.

So, finally (though I bet it isn't the last time I ask) - given my existing set up is 1x15 plus 2x10, what should be the perceived difference in using either an 1818X or an 1818 plus my 2x10? Or, indeed, an 1818X and a 1x15?

Or replace the 2x10 with a 4x10 and use that in combination? I mean a 4x10 plus 1818 has significantly more speaker surface area for the same 300W 4ohm as my 1x15 and 2x10, so I guess it is going to be louder, but are there any advantages?

This is all assuming my back lasts out, of course. I am leaning towards 1818 and 2x10, as they more portable (relative term, of course)

Thanks for your patience!

[Hamster]

There are too many unknowns for the speaker/cabinet specs to give really specific advice as to what combination [i]should[/i] be perceived to be louder. The bottom line is your ears, cab placement, venue acoustics etc and what tone / sound you're happy with rather than squeezing the last theoretical dB of sound out of the rig.

Have a look at Alex's musings on his website, which is a pretty interesting read - [url="http://barefacedbass.com/technical-information/Volume-displacement.htm"]http://barefacedbass.com/technical-informa...isplacement.htm[/url]

[chris_b]

Modern 10's and 12's are so well designed that they can produce much more bass than an older 15 or 18. They can cost a bit more but the difference is well worth it in my opinion.

[Delberthot]

the 1818x was designed to be used with one of the bi-amp trace heads like the AH500x so you could feed the lows to the 18 and the highs to the 10. I think it runs full range when connected to a normal amp.

One input is full range and the other is biamp, one is 1/4" jack and the other is XLR

I think

[Ghost_Bass]

Why on earth do you want more than a 1x15"+2x10"??? I had the same setup ( 300W GP12 head + 1x15" + 2x10"H ) and could never go past 4/10 in volume without starting to overwriting the bar's PA (not to mention the rest of the band )!

You should know that TE's 300W are pretty much the same as modern makes's 500W or more! With a stack of a 300W head + 1x18" + 4x10"H cranked up i'm shure you could knock down some thick walls

[Colledge]

[quote name='Ghost_Bass' post='955918' date='Sep 14 2010, 12:42 PM']You should know that TE's 300W are pretty much the same as modern makes's 500W or more! With a stack of a 300W head + 1x18" + 4x10"H cranked up i'm shure you could knock down some thick walls [/quote]

+ a 1, my 280w trace head seems alot more powerful than my old mag600 setup, but i think that has alot to do with better quality cabs too.

[Paul S]

Why more? Well, I don't really want it any louder - I don't think I have used the volume above half even with a low gain setting - it is more about the quality of the sound.

Ever since I played through an 18" TE cab once at a rehearsal studio I've been striving for the same sound and, although the 1x15 and 2x10 are great, I want to get that richness that I got that time with the 18" cab - reaching my personal bass tone nirvana. I was just really canvassing opinion about my options. I was just initially puzzled by the watts/ohms thing - part of the jigsaw I am trying to piece together in my brains about all this.

Anyway, as ever I appreciate all the input - many thanks.

[Ghost_Bass]

[quote name='Paul S' post='956054' date='Sep 14 2010, 02:42 PM']Why more? Well, I don't really want it any louder - I don't think I have used the volume above half even with a low gain setting - it is more about the quality of the sound.

Ever since I played through an 18" TE cab once at a rehearsal studio I've been striving for the same sound and, although the 1x15 and 2x10 are great, I want to get that richness that I got that time with the 18" cab - reaching my personal bass tone nirvana. I was just really canvassing opinion about my options. I was just initially puzzled by the watts/ohms thing - part of the jigsaw I am trying to piece together in my brains about all this.

Anyway, as ever I appreciate all the input - many thanks.[/quote]

In that case put your 15"er up for trade for a 18"er. But in your case i would try a crossover on both cabs to try tailoring their sound to your flavour first. If it works you would get the sound you are looking for with less expenses and less weight. i realy don't believe the 18"ers would go so further down than a 15"er to have such a great impact! I think you would get more punch in your sound but the 15" is low enough

Try it all and go for whatever makes you happy! That's the most important thing.

[Paul S]

[quote name='Ghost_Bass' post='956061' date='Sep 14 2010, 02:50 PM']But in your case i would try a crossover on both cabs to try tailoring their sound to your flavour first. If it works you would get the sound you are looking for with less expenses and less weight.[/quote]

Interesting. What does that involve, and is it something a technophobe like me could manage?