Speaker sensitivity and amp break-up?

[Benny Lamb]

Does speaker sensitivity affect the point my amp starts to break up? does a 98 db speaker break up sooner than a 101db speaker? Or is the db rating just a mesurment of how loud the speaker is?

[bluesbreaking]

Sensitivity has less to do with the breakup point than it does with loudness. That depends on the power handling of the particular speaker and the actual speaker in question: certain 30-watters will sound distorted sooner than others.

[fillmore nyc]

Does speaker sensitivity affect the point my amp starts to break up? does a 98 db speaker break up sooner than a 101db speaker? Or is the db rating just a mesurment of how loud the speaker is?

Sensitivity has less to do with the breakup point than it does with loudness. That depends on the power handling of the particular speaker and the actual speaker in question: certain 30-watters will sound distorted sooner than others.

I'd love for Jim at Scumback to jump in on this one. My guess (guess) is that an amp would break up sooner with a low efficiency speaker because you'd have to run it at a higher volume to obtain the same dB output than with an efficient speaker.

If a 50 watt Plexi was used with a pair of EV's (VERY efficient), and the player needed to run the volumes at "4" to fill the room he was playing in, then doesnt it make sense that if a really inefficient pair of speakers was used to obtain the same room filling volume, the amp would have to be run at "6" or "7", meaning its gonna break up more simply because the amp is being driven harder to obtain the same volume?

Again, this is just a guess, but it seems to make sense (at least to me ).

PS-Welcome to the Forum, Benny!!!

[Scumback Speakers]

I'm going to speak in general terms since suspension stiffness, cone stiffness/thickness, doping, etc all play a part in how a speaker sounds (or breaks up).

Lower weight magnets, such as the G12S (around 25 oz), and the G12M (30-35oz depending on spec, and who you believe) will break up sooner since the weight of their magnets can only control a speaker's cone so much due to their magnetic power. What that means is that typically a louder speaker has a bigger magnet, and controls the cone from moving as much, and usually increases the sensitivity/loudness/efficiency since the magnet is bigger/heavier/more powerful.

So a G12M (35 oz) will break up sooner since it can be sent a signal that moves the cone earlier than a G12H (50 oz). Of course, bigger magnets need a bigger signal to move them, so an EV or JBL, with 7-8 lb (112 to 118 oz) magnet is louder, harder to break up, more efficient.

Regarding volume levels for filling a bar/dance floor (around 2500 sf using the same exact guitar, amp and 2x12 cab), I've done a few tests using my Gibson Super Goldtone 30w amp.

G12M, 97db: master volume at 6.5

G12H, 99/100db: master at 4-5

JBL/EV, 102/103db: master at 2-3

This was used with a drummer/bass, 2nd guitarist and keyboard to be heard at the same levels, same stage in the same bar.

So here's the semi-sort of tested bottom line in real world tests.

The JBL/EV models are the loudest, but don't really have the tone goods at a master volume setting of 2. The MV amps don't work all that great at 2 with these speakers since they're not getting a volume signal to make them wake up from their 150-200w power handling nap. Great for clinical/sterile sounding cleans, pretty weak for classic rock/higher gain tones, as they're very ear piercing.

G12H's (H75 Scumbacks) 30w: You get a pretty powerful tone here since the MV is over 1/3rd, so it's opened up a bit and not sounding thin. Broad frequency response, but even, not a big hump in the mid response. Big cleans, good lows, even mids, clear treble, cutting OD but nice all around tone (IMO).

G12M (M75 Scumbacks) 25w: Big mid response, a tiny bit of flab on the low end when pushed hard, which can happen at volume levels of 6-7. Clean tones are a bit grainy/cloudy (due to speaker breakup), OD tones are bigger, but with less overall frequency response (like the H's).

So your speaker's design will influence where your volume is set to achieve certain tones/clarity. You just need to figure out what you need! LOL I guess this is why my M75/H75 mix is getting so popular lately, though.

Hope this helps.

[Benny Lamb]

Thanks for the tips. Sounds like I want a lower db rating so I can work my amp harder to get the sound I am after.

[Scumback Speakers]

Thanks for the tips. Sounds like I want a lower db rating so I can work my amp harder to get the sound I am after.

That's what most players do. Good luck!

[908ssp]

Or get the speaker that gives you the tone you want and let the attenuator control the volume. A good attenuator of course.

[Benny Lamb]

Or get the speaker that gives you the tone you want and let the attenuator control the volume. A good attenuator of course.

What would you consider is a "good" one? I have tried the Hotplate and Weber and didn't like them much.

[demonufo]

Faustine Phantom, Alex's Attenuator, Aracom Pro, Ultimate Attenuator (but not strictly just an attenuator, since this one attenuates and then re-amps via a solid-state amplifier).
There are others, but these are the big boys.

Edit: Oh yeah, and some guys rave about the Marshall Powerbrake, provided it has had a certain cap removed from the stock circuit. I tried one once and didn't rate it much, but then I hadn't tried the cap removal trick, which apparently is a night and day tonal change according to some.