Why use a 1X15 Combo Amp?

[Restless Rocks]

I guess if you're playing Jazz guitar ala George Van Epps (7 string) or Pedal Steel where you want maximum clean headroom and a bigger, thicker sound. The 15 also has a little bit more usable low frequency responce. I'm wondering why they aren't more popular with those who drop tune and go for the deep chunk sound. And besides SRV liked them for his particular sound.

 

[Ercek]

Being a guitarist and a steel guitarist, I own both a Mark IIB 1x12 and a 1x15. The 1x15 serves steel guitar very well because of the low end bass strings on a steel guitar with the traditional C6th tuning. Gauges can get down there; 3 or 4 strings ranging from .070 to .046 in gauge. Given the same 100w power, it's easy to breakup a 12" speaker, but much more difficult to do with a 15". Steel players seek clean, powerful amps. Weight wise, they're pretty close not as dramatic a weight difference as you would think.
From The Boogie Files......"This configuration is superb for steel guitar or clean lead guitar work as the amps have incredible tone and clean headroom. The 'pull deep' on Master 1 knob that appears on the Mark IIC+ and Mark III amps is perfectly voiced for pedal steel."

 

[212Mavguy]

15 inch speakers do a couple of things:

one, they tend to provide more low end and lower mids at the same tone settings, that allows more harmonics to come though if you back off the bass knob til you get the same amount of bass as a 12... if you are playing through a relatively full range guitar friendly 15 inch speaker. Makes for a richer, fuller sounding lead tone if you have the right 15 inch speaker. If the amp isn't working as hard for a given volume setting pushing high wattage demanding low note sound waves through the system there will be less mud in the tone at high volume settings. Blues tones sound particularly nice through one or two 15's.

two, they tend to be more efficient watt for watt volume wise,

three, if you hit a low droning note and simultaneously hit a couple high ones on a cheaply made 15 it will sound like muddy crap, the same thing will not drastically effect a 12, think the more massive 15 inch cone is at fault. The EV 15l will not be plagued by this problem, Cast frame speakers with large maghnets tend to not be as affected.

four, the 15 inch speakers will project their sounds further away from the cone than a 10 or 12. If you put yourself 20-30 feet back from a 15 cab and a 12 cab side by side you should hear a pretty good difference, especially in a crowded room.

Some 15 inch speakers were designed to work for lead guitar. Some work by accident. Hope this helps.

 

[t0aj15]

Referring to the old IIB or IIC(+) Combo Amplifier with the 15” EVM 15L Speaker

What's the benefits (if any) of the larger speaker in a guitar cab?
What's the downside (if any - obvioulsy it'll be heavier).

They move more air.... ok but I'm somewhat baffled why one would use a 15" vs a 12" speaker in a guitar cab.

I didn't go the combo route but I am using a 15" Eminence Commonwealth in a sealed back/front loaded cab with my Mark IV short head. I fell in love with the sound of 15's back in the early 70's when I used a 2x15 cab loaded with a pair of Electro Voice SRO's. I'll answer your last question with a question, why would anyone use a 12" if they could use a 15"? IMO if I have a choice between a 12" and a 15" of the same model I'll take the 15".

 

[Monsta-Tone]

I had a Fender 75 amp, sort of a Mark I clone. Fender was trying to compete with Mesa in the early 80's. Pretty funny!

The amp had an EV 15. It sounded so massive and warm. I've tried the 12L in a Rectoverb combo cabinet that I converted to an extension cab. It sounded pretty close, but the 15 just sounded even more full.


I sold the amp though, because it had been stored in a carport for 15 years and I just kept having problems with it.