Amp/cab combinations. Too much maffs, guvnah!!

[LowMoFo]

Hi all,

The button said 'Start New Topic'. I doubt that this is 'new' by a long way, so with apologies in advance...

 

Can anyone recommend a good book, or a comprehensive (and I mean it) website to educate me on music-based electrickery?

I ask this because I have a TC 500w head, and I want to get some cabs without blowing anything up.

I'm struggling with my lack of electrickery knowledge (I can't see it, therefore I don't get it), and it's really starting to get on my tits.

 

My amp: 500w @ 4ohms, 250w (or 300w) @ 8ohms.

Cab option A: 10s + a 15 (wider freq range)

Cab option B: Just 12s (Because I'm lazy & this is allegedly a compromise twixt 10s & 15s)

 

I understand that 2x8ohm cabs will result in a 4ohm load. That much I get. This will draw an output of 500w from the amp.

The amp is only ever gonna chuck out 500w max, split between whatever cabs I put them through. Right?

Given (of course) that I'm not pissing about with 2.6ohms etc. 

So. I hunt down cabs which are ultimately rated at 500w each. Right? Or combined? Or what?

By now, if you've got this far, you're no doubt very aware that I overthink pretty much everything.

But it's only because I don't want to kill myself this way. You know, without warning.

Go on, go to the drinks cupboard, I'll be here.

 

Same with the 12" option. 500w 4ohm cab?

And then we come to headroom. For the amp? Cab(s)? is both possible?

 

I hate my brain. It hates me back. Any advice/suggestions/firearms desperately needed & greatly appreciated, as always.

I'll see my self out...

[Downunderwonder]

Not sure 500w of TC is worth the sticker excitement but with 4 ohm worth of cabinet(s) should make plenty of noise enough to keep up with a drummer.

 

The key to cabs making noise with watts is their broadband sensitivity. Cabinet makers make up even bigger stories about what "wattage" their cabs handle.

 

A 2 cab solution can be handy for relatively low volume situations allowing a single cab.

 

Some expensive 8 ohm single 12 cabs will do enough with the nominal 250 watts from most 500w amps. TC infamous for massively overstating theirs.

 

2 of the same cabs will always work well together.

[Woodinblack]

Power is shared between cabs, if they are the same load, so two 250w 8r cabs work as a 500w 4r cab together.

 

I gig either a BC 300w 12" 9r cab, or 2 250W 12" TC cabs (used to use 1 for practice 1 for live) with a ABM600. So the amp has a higher rating than the 2 cabs, but thats ok, it never gets turned up full.

On your list, cab option B is most certainly better than A.

[Chienmortbb]

I will try to be brief. You will not find everything you need in one book. I am always happy to be corrected, but here is my two pennyworth.

 

TC amps are notorious in exaggerating their ratings, BUT they are plenty loud enough for most. In explanation, they use a lot of processing and especially compression to give the impression of being much more powerful than they are. However, your amp is a very capable amp and in most cases a good one cab setup should work well.

 

Most on here will know my bent as far as cabinets go, and of course it would be good to know your budget. All online retailers must let you change your mind. I cannot remember whether you get 10 or 14 days to change your mind, but you could use that to try some cabs. UK based companies like Barefaced and LFSys offer better than that, as well as both having helpful owners. @steviefrom LFSys is often on here and can be contacted via private message for advice/ Alex Claber from Barefaced is also very helpful according to those that have asked him questions and bought his cabs.

 

Depending on your DIY skills, there are free designs on here for the BC112 Mk3, and some easy build 12" and 10" cabinets and of course Bill Fitzmaurice sells plans for DIY cabinets and is often on here.

 

LFSys

Barefaced

Bill Fitzmaurice

 

If your goal is the lightest cabs, Barefaced. If the lightest that give the best performance, LFSys. However, others may disagree. Only you know what is right for you.

 

 

Edited October 3, 2023 by Chienmortbb

[Japhet]

I switched to a single 2x12 4 Ohm cab for bigger gigs and it ticks all of the boxes with plenty to spare. I use a more compact 8 Ohm cab in smaller venues. Gone are the days of multiple trips to the car to load and unload. 

[chris_b]

14 hours ago, LowMoFo said:

Can anyone recommend a good book, or a comprehensive (and I mean it) website to educate me on music-based electrickery?

 

All you need to know is any 500 watt amp, 1 or 2 Barefaced 112's, leads and a bass and you've cracked it.

[jrixn1]

16 hours ago, LowMoFo said:

I want to get some cabs without blowing anything up.

 

The cab rating is more of an approximate guide than a strict guarantee that everything will be ok.  You would be fine with a cab rated at 200W, if you play at a lower volume - or you could damage a cab rated at 700W, if you maxed out the EQ and played very aggressively etc.

 

If you do want specific cab recommendations, indicating your budget, musical genre/band line-up, and venue type/size will help get the best suggestions.
 

[Lozz196]

I’ve always tended to go for an amp that I think will have far too much power for my needs, then matched it with cabs that - on paper - have at least an equal but preferably a higher power handling. I figure this way I’m less likely to blow anything up, and unlikely to be in a position where I haven’t enough volume.

[chris_b]

2 hours ago, Lozz196 said:

I’ve always tended to go for an amp that I think will have far too much power for my needs, then matched it with cabs that - on paper - have at least an equal but preferably a higher power handling. I figure this way I’m less likely to blow anything up, and unlikely to be in a position where I haven’t enough volume.

 

This.

 

I either run a 500 or 700watt amp into 1400watts of cabs. Even with a 5 string bass at volume there is zero chance I'm going to damage the drivers, or sound bad by over driving the amp.

[Lfalex v1.1]

Without wishing to cloud the issue,  it IS possible to run a big amp into a cabinet with a lower power rating IF YOU ARE CAREFUL.

 

I've used a QSC PLX 1202 bridged into a Trace Elliot 2103H. 

 

That's ~600w @ 8 Ohms into an 8 Ohm cabinet that's good for ~160w.

 

In fairness,  I had the QSC's HPF on, and only "kept up" with the rest of the band, but it worked fine. 

[DJpullchord]

Get an amp with twice the output you think you need, make sure you use a limiter. Run it gently.

I’ve found the guys at the speakerplans forum incredibly helpful, when seeking advice on all things amp and speaker related.

[bassman7755]

Hes my simple as possible common sense advice:

 

Dont worry about complex calculations and using juggling impedences to extract the maximum power from an amp, any of the following will do just fine:

A single 4 ohm cab.

A single 8 ohm cab.

Two 8 ohm cabs in parallel (the default wiring scheme for amps and cabs with multiple connectors).

Yes two 4 oms in series technically works as well but ... why would you ? its fiddly needing custom cables an less effecient than 2x8 in parralel.

 

Dont obsess over driver size, the design and quality of the cab is much more important, any good 10 or 12 loaded cab can produce the necessary frequency range.

 

All other things being equal more speaker cone area moves more air using less amplifier power irrespective of whether this is achieved withing the same cab or multiple cabs stacked. 2 * 10/12 drivers should enough to get a decent volume with a mid powered amp like yours.

 

Dont worry about over powering the cabs, really just dont so long as your using one of the configs listed, actually damaging any half decent bass cab with a mid powered amp is very hard in practice unless you are deliberately setting out to abuse it (and if you are abusing it having an amp with a lower nominal rating than the speaker is not an absolute gurantee than you wont do any damage).

Edited October 14, 2023 by bassman7755

[Bill Fitzmaurice]

What's not been mention is that cab power ratings are thermal. In the vast majority of cases they run out of mechanical power capacity at well below their thermal rating, in many cases at no more than half the thermal rating. AFAIK the only brand that gives their mechanical rating is Barefaced. The good news is that when the mechanical limit is reached the driver will distort, giving you fair warning to back off the volume. But that does you no good if you use distortion effects, so if that's the case you have to be very cautious.

[bassman7755]

On 05/10/2023 at 14:10, Lfalex v1.1 said:

Without wishing to cloud the issue,  it IS possible to run a big amp into a cabinet with a lower power rating IF YOU ARE CAREFUL.

 

I've used a QSC PLX 1202 bridged into a Trace Elliot 2103H. 

 

That's ~600w @ 8 Ohms into an 8 Ohm cabinet that's good for ~160w.

 

In fairness,  I had the QSC's HPF on, and only "kept up" with the rest of the band, but it worked fine. 

 

Back in the day my setup was a QSC PLX bridged with a rated output of 1600 watts rms into cab rated 750 watts. Thats playing rock/metal with a 5 string in a loud band. Realistically I was probably only ever using 2 or 3 hundred watts as that is pretty loud through any reasonably effecient cab, the surplus power is only there to keep the transients clean.

Edited October 16, 2023 by bassman7755

[msb]

I like a modular system so I went with two 8 ohm cabs. Most of the time I can easily get by using just one cab. I enjoy modern lightweight gear. 
I went with a 112 and 210 pair that were designed to be run together.