VOLUME: 1x12 vs 4x10 @ 8 ohms ?

[fr8_trane]

Lets say you have a 22 watt amp driving a single 30 watt 8 ohm speaker. If you run that amp thru a 140 watt 4x10 8 ohm cab how does the overall amp volume change?

1. Its louder through the 4x10 at the same volume setting because the amp only sees another 8 ohm load but its now driving 4 speakers instead of 1.

2. Its quieter at the same volume setting because even though its still 8 ohms you are now driving 4 resistive loads instead of 1.

3. Its quieter because you have 22 watts trying to power a cab rated for 140 watts. In my electrical ignorance I may just be rephrasing 2 but I've heard this one from other players so I thought I'd trow it in.

4. Insert correct answer not mentioned above.

I always thought the same amp driving more speakers would be louder than just a single speaker but now I'm not so sure. Please enlighten me.

 

[Rod]

Well, I think it's certainly a lot fuller running 4 speakers instead of one...More low mids and bottom for sure..Louder?? I wouldn't say so...

 

[Jerrod]

Totally depends on the efficiency of the speakers, etc. etc. Max power of the speakers/cab is irrelevant to the perceived loudness.

 

[fr8_trane]

Well I agree with both of you that the cab will sound beefier in the lowend and that speaker efficiency will have a great impact on overall volume. However, lets say its a 4x12 cab with 4 speakers IDENTICAL to the one in the combo.

My gut tells me 4 speakers should be louder than 1 but my head is telling me it MUST take more POWER to drive 4 speakers. Maybe its a push.

I guess my main question is what is the limiting/determining factor - impedance (which remains constant) or ....what?? Dissipation? Resistance? There has to be a physical difference between 4 speakers and 1 speaker as far as what the amp sees even if the impedance remains the same.

 

[treeofpain]

Isn't resistance resistance. In other words, 8 ohms is 8 ohms, regardless of how you get it. So I would not think the ohms would be a factor.

The 4 speakers will disperse the sound differently and make it seem louder. The design of the cab will affect this too.

A stated before, the efficiency/sensitivity of the speakers will be a big factor in the loudness. If you have ever stuck a JBL or EV in a single 12 combo, it is usually louder due to this. The frequency response of the speakers can also affect perceived loudness.

 

[aaronbarnes]

I think the single 12" will sound bigger, because it's getting all 22 watts and being pushed to its happy place.

each 10" will only be getting 5 1/2 watts and that's not even half of their rated power in this hypothetical sitieayshun.

the tens will never get close to breakup or thier happy place and you'll lose dynamics

I think the 12 would be more fun.

 

[Troubleman]

40 inches of speaker vs 12 inches of speaker putting out your sound. For that reason (and multiple speakers) the 4x10 will sound louder... and fuller.

jb

 

[bosstone]

I think that is a very hard question to answer for several reasons. First is "overall volume" isn't a specific enough term. Speakers accentuate (make louder) certain frequencies. Second, some speakers are very much more efficient (louder) than other speakers. Third, cab size, shape and design also greatly influence loudness and what frequencies get emphasized. Different speaker/cab combinations could have one with higher frequencies being very loud comped to the second one while second one's bass might be quite a bit louder than the first.

Resistance is resistance so that is not a factor assuming the amp and speaker/s have matched resistance. One 8 ohm speaker has the same 8 ohm resistance as 4, 8 ohm speakers wired series/parallel.

When comparing one speaker driven with, let's say 100 watts of amp output, vs. 4 of the same speakers sharing 100 watts, obviously each of the four gets only 25% of the power and will not, individually be as loud as if it received 100 watts. Four speakers will generally be housed in a much larger cab than a single speaker cab. The larger cab will generally have a much greater bass response, and will move more air. The bass will be louder and the sound will be more harmonically rich because of the four cones "harmonizing" and you will hear the "size" of the sound. Bigger sounds louder, though I have played through a 100 watt Boogie MKIIC+ sith a single EVM and had no trouble at all being heard over a Marshall JCM 800, 100 watt full stack. I don't know if more knowledgeable people will agree or actual sound pressure measurement would verify all this but this is my experience.

All this being said. I find that a bigger sound is more impressive and satisfying than a louder sound. More speakers and/or larger cabinets have been the only way for me to get the type of sounds I am looking for. I have found that I can get this type of sound with a Marshall 1965B cab or with a home built detuned single 12" cab and I am able to get a very big sound even at surprising low levels when used with an Ampeg VL 502 with it's built in attenuator. You just have to find out for yourself what combination of equipment produces the sound you want and there are a lot of ways to get there.

On the other hand, I have been having a lot of fun lately with a little Fender single 8" combo too.

 

[fr8_trane]

Alright I'm getting closer to fully understanding it now. The power is split evenly over all 4 speakers so each speaker would be individually quieter than the single 12 but together they should technically put out the same total volume and power.

Part 2 of the equation is the enclosure and its effect on frequency response which is sort of self evident. We all know the difference between a small combo and a large closed back cab.

One question is left. What about the speaker area. The power is evenly distributed, yes, but its distributed over a much larger area. Shouldn't this make it LOUDER?

 

[bosstone]

Not much. If loudness is what you are looking for, get more efficient speakers or a lot more wattage.

 

[ontariomaximus]

Front baffle size has something to do with it also. A bigger baffle with the 4 x 10 will be louder. A speaker is twice as efficient propagating into a hemispherical space rather than a spherical and the larger baffle lowers the frequency where it switches from hemispherical to spherical. Which reminds me I have to build a super oversize 1x12 cab one of these days.

 

[bosstone]

I don't know what you consider to be a super oversize cab but I built a 24" X 16" X 30" detuned cab for a single 12" speaker and I have great efficiency and frequency range. It sounds much more like a 4 X 12" cab than any 2 X 12" cab I have heard.

I'd be interested in knowing more about hemispherical cab effects etc. Are you talking about cabs or the room the speakers are working in??? Who makes them? Baffle board effecting efficiency? Tell me more.