High Power Heads into single 12s

[stufunkybass]

Hi All, 

 

Been a long time since I posted on here but wanted some thoughts.

 

I hear about a lot if bass players using 800 watt heads into single 12" cabs.

 

GR Bass do an 800 watt combo where 400 goes into the enclosure. I have also seen videos of Magellan 800 being user into MG12T cab.

 

What are peoples thoughts. I know you can't defy the laws of physics an all that. 

 

I have a Magellan 350 into the MG12 and debating adding a second cab or going with the above option.

 

Are there any of you out there using similar to the above (800 watt into single 12).

 

Cheers

 

Stu

[yorks5stringer]

Not an expert but I think the advice is it's fine as long as you use your ears:  obviously if the speaker starts flapping you are giving it too many beans, so back it off unless you want the cone to detach! Assume it is an 8 ohm speaker not a 4?

Edited June 3, 2022 by yorks5stringer

[chris_b]

Any amp will go into any cab, as long as you match the watts to the cabs capabilities.

 

Doubling the power of the amp will give you very little extra volume. Adding a second cab will give you a lot more volume and better tone, simply by moving more air.

 

Most 112 cabs are 8 ohms, so when you see an 800 watt amp being used it's only putting out 400 watts at the most, and most of these amps will not be running flat out. I am probably using 150-200 watts when I#'m running my 800 watt amp into 1 cab.

Edited June 3, 2022 by chris_b

[Downunderwonder]

You'll get way more volume from a 2nd cab with that amp than you would from trying to squeeze every last bit out of the one cab with a bigger amp.

[pbasspecial]

Used to use a single super compact with 500w heads. Sounded great. Sounded better with 2 cabs. Needed the cash sold one. Sounded less better with just the one cab. Bought a Super Twin. Problem solved. 

[Bill Fitzmaurice]

So long as the amp has a volume control no worries. Two salient points: First, if you're running at half perceived maximum volume an 800w amp won't be running 400w, it will be running 80w. Second, few speakers are able to take even half their rated power before they distort badly. When that happens turn it down. If it happens on a regular basis you don't need more power, you need another preferably identical cab.

[Chienmortbb]

Two cabs will give you more volume but a well designed single 12" cab will probably be all you need. Modern 12" drivers have the excursion, moving more air and with a properly designed crossover and high quality compression driver/horn combination you will probably never need another cab.

 

Bill is right that no speaker can stand 800W continuous no matter what the manufacturers say and if a you get to even half the rated power, power compression will kick in. Beyma used to publish power compression graphs and in general half power continuous meant a power loss of about 1.5-2dB. it was closer to 4 dB at rated power. I have seen nothing to suggest other manufacturer's drivers are any different. Luckily as @Bill Fitzmaurice  said, most of the time we are using a few watts. When you have cabinet with a sensitivity of say 98dB at 1W then 16 watts gets to 110dB and  128 watts gives 119db. That would be loud enough for most situations even allowing for power compression.

 

Two cabs will give you more volume or allow you to to run them at a much lower volume. Many people run two cabs so they can hear themselves. The poor dispersion of bass drivers means that you can barely hear a cabinet around your feet. Adding a compression driver, well designed crossover and wide dispersion horn at the top of the cabinet, will allow you to hear your playing.

 

Edited June 3, 2022 by Chienmortbb

[Lozz196]

Yep, use your ears on this, and especially the volume control.

[Bunion]

Get yourself a Greenboy Fearless f112 and you won’t put enough power through it before it gets to loud 😄

[fretmeister]

Ashdown RM800 into a 1x10 Barefaced One10 

 

Its great. It has a volume control.

[Jack]

I used a head that was theoretically capable of 800W (GK Fusion) into a very small cab (original BF Midget) for loads of gigs. The volume control works both ways and I never gave the little 8 ohm speaker anywhere near the c 500W that head could have given it. 

[Phil Starr]

It's always hard to judge how much detail people want. The way we measure output of amps and the power handling of speakers is entirely different and separate and power handling for the speaker isn't the same at every frequency. On top of that the input you are using is music and not a test signal.  All music definitely isn't alike. Another issue is sound level: you can drive a 12" speaker to it's limits easily with 200W and few of them are thermally rated above 300W so why make a 600W speaker if it is no louder? You can give it a bigger coil which increases power handling and then trade some of the extra power for driving a heavier cone of having a stiffer suspension but you rapidly get to the point where you are trading a lot of expense for marginal gains in performance. A lot of the boutique modern 12's have drivers chosen to be around this point to get the most that is economically sensible out of a single 12. They will probably not handle 800W if you run everything flat out with loads of distortion and bass boosted and won't be much louder anyway than if you use them within their recommended limits but if you are running any normal sort of signal into them and have the volume and bass anything other than maxxed out then you'll be fine. In any case you'd be running them at levels which would be damaging your hearing and overloading the vocal mics long before they reached the point of failure.

[Jack]

12 minutes ago, Phil Starr said:

... In any case you'd be running them at levels which would be damaging your hearing and overloading the vocal mics long before they reached the point of failure.

Have you seen most pub bands? 

[Skinny]

Plus one for using your ears and the volume pot. Speaker cab ratings are just as wild as amp ratings I think. I opened up a very well known brand new 200w 1x15 once to find a speaker rated at 100watts. I bet that is not unusual. 

[stewblack]

Funnily enough,  I used a 1k head into a single 12 this evening.

Sounded super.