Based on the last two video's of amps I have fallen in love with, a Tweed Bassman, and an AC10 Twin, I have a suspicion that multispeaker combo's have something special going for them over single speaker combos. There just seems to be so much animation and swirl.
Does anyone else have thoughts on this?
I wonder if it has to do with phase cancellations between the speakers. Or could there be electro-mechnical interactions between the speakers?
It just seems that single speaker combos are meh, but two or more speakers add a liveliness and richness.
Or is my imagination just trying to get me to exercise more.
maybe because there is more empty space on the baffle between the two speakers? More wood would mean more tone.
I am about to build a 2x10" version of my 12" Milkman combo - the Mather cabinet arrives tomorrow. I am really looking forward to comparing the two versions. I will let you know how it turns out to have 2 of the exact same amps, with the same type of NOS tubes one with a single speaker one with 2 - seems like a pretty good test.
Milkmansound wrote:maybe because there is more empty space on the baffle between the two speakers? More wood would mean more tone.
I am about to build a 2x10" version of my 12" Milkman combo - the Mather cabinet arrives tomorrow. I am really looking forward to comparing the two versions. I will let you know how it turns out to have 2 of the exact same amps, with the same type of NOS tubes one with a single speaker one with 2 - seems like a pretty good test.
Thanks! I would definitely be interested in your observations.
In closed back cabs, I much prefer two cones over one. Sounds bigger, wider, but still focused with crunch rock chords. But open back cabs are awesome for chime and squirrel, and one cone sounds great. I think you get a lot of phase color from open back cabs. Pretty basic observations, I know.
I build and repair tube amps. http://amps.monkeymatic.com
xtian wrote:In closed back cabs, I much prefer two cones over one. Sounds bigger, wider, but still focused with crunch rock chords. But open back cabs are awesome for chime and squirrel, and one cone sounds great. I think you get a lot of phase color from open back cabs. Pretty basic observations, I know.
Well the phase issue is pretty huge in open backs, isn't it? You put it in the corner, it sounds one way, you put it center-stage, something else. But the designers were not unaware. Weren't the earliest 15" Bassman amps ported?
The big cabinet with the big hole takes the cabinet out of the equation to an extent. One of my beefs with single 12 cabs is that they nut up the lowend in a very peaked way. If it is open, it may as well be just about wide open. Combos are so dependant on placement in a space. I love predictable and consistant more than anything. Like, a Super Reverb seems to have at least 100% better chance of sounding good to me if I can get 4' off a wall out of a corner, whereas a Deluxe is all finicky and sometimes just won't do awesome unless you trap off the area behind it no matter where it is. If you have to haul around gobos to trap a space, may as well bring out the heads and 4x12s.... Predictable!
1x12 combos are loved by microphones though. <3
I wish my Fletcher would stop picking on my Munson. hah I am too accustomed to the thump. I need to go back to jazz on a proper guitar for a while. Open small boxes make me play to the amp a lot more than anything else, I think.. team weedle.
Oh,and why do AC30s ignore physics. Sounds great anywhere.. no idea.
Reeltarded wrote:The big cabinet with the big hole takes the cabinet out of the equation to an extent. One of my beefs with single 12 cabs is that they nut up the lowend in a very peaked way. If it is open, it may as well be just about wide open. Combos are so dependant on placement in a space. I love predictable and consistant more than anything. Like, a Super Reverb seems to have at least 100% better chance of sounding good to me if I can get 4' off a wall out of a corner, whereas a Deluxe is all finicky and sometimes just won't do awesome unless you trap off the area behind it no matter where it is. If you have to haul around gobos to trap a space, may as well bring out the heads and 4x12s.... Predictable!
1x12 combos are loved by microphones though. <3
I wish my Fletcher would stop picking on my Munson. hah I am too accustomed to the thump. I need to go back to jazz on a proper guitar for a while. Open small boxes make me play to the amp a lot more than anything else, I think.. team weedle.
Oh,and why do AC30s ignore physics. Sounds great anywhere.. no idea.
THAT is an interesting observation: front surface area versus back surface area in a combo. How much of the back "out of phase" audio is blocked/damped in different combo configurations?
When I am recording a combo I get it WAY off the ground but never too far from a wall, and it overhangs the front of the 'riser' as far as the front feet will allow. Focus on the microphone sounds more correct about 4-6 inches farther out on the same day I am shoving similar mics down the throats of 4x12s.
Another thing that might give you a few clues as to what is really going on with phase in a little one is that I might use a single ribbon out in front, and a single ribbon in phase with but out back. They are all Fig-8, ribbons... so the one in back is facing the wall but FOR picking up the out of phase rear projection from the amp to complete the reality of what that amp sounds like. Either mic sounds incomplete bynitself. They are arranged so the wave is coherent between tracks within a couple milliseconds.
Some guys are so anal they use digital delay to make sure the signals arrive in sync. Helps for drums sometimes. Not sure about guitar amps. Bass amps you can usually flip the phase of the output so you can control how much bass is in the room signal (if you record that way).
Between 1X12, 2X12, open and closed boxes will all sound different.
More inches of piston (2X12) will present more dynamic volume/tone
than a single 12. The cabinet material obviously will have an impact on the tone, pine vs plywood vs MDF.
All in all, it all depends on what your ear requires. Going for vintage...
a pine open back is the ticket. More focused mids, a closed box.
I use a small single closed 12 for a foldback on the front line that I sometimes mic, if the stage is tight for space. With more space allowed, either a Bag End with an E JBL and EV 12L, or a 1966 Marshall
loaded with 2X12 EV 12L's and 4 - 2 inch ports bored into the back to let it breath some. This can run as a WDW, Stereo, or mono.
I can mic all or one... they (speaker cabs) all sound different.
If I need more presence in the mix, mic the JBL... for a brighter, hard reflective surfaced room, move the mic closer to the EV, or use the other box with the 2 EV's.
From a "high brow" technical point of view there are two(2) differences which stand out like the proverbial canine testicles.
First with2 speakers it is going to be twice as loud as an amp with an identical single speaker OR for the same volume with 2 speakers the amp will be putting out half the power and therefore not straining.
The next has to do with those Thiele Small parameters.
Speakers have a mechanical damping factor - Qms
and and electrical damping factor - Qes
Generally for a HiFi speaker box etc they will quote Total damping factor Qts which is the RMS value of the the mechanical and electrical damping factors.
The ability of an amp to damp a speaker is dependent ONLY on the Qes factor, something the HiFi nutters often forget, so they say my amp has an output impedance of 2 Ohms and my speakers are 8 Ohms so I have a damping factor of 4 - it actually only describes the interaction of the amp with the Qes and has no effect on the Qms.
Now Guitar Amps typically have very high output impedances (10 Ohms and higher is not that unusual) so they are not that great at controlling the speaker (damping the Qes).
BUT
if you have 2 speakers in parallel then each speakers Qes is not only electrically damped by the amplifier output impedance but also electrically damped by the other speaker which is wired in parallel with it. This will change the sound to a more controlled sound compared to a single speaker. It is this 2 speakers wired in parallel that I would guess is what you like to hear.
If you like the lack of damping of a single speaker but want it louder then use 2 speakers in series. In that case the speakers do NOT electrically damp each other.
In a closed box and possibly in a combo to a much smaller degree, each speaker will tend to contribute mechanical damping to the other as well. As one speaker tries to pump its cone forward it produces a low air pressure behind the cone which will oppose the other speaker trying to pump its cone forward.
Oh Ian,
Now you're talking about stuff above my paygrade. I am going to have to chew on that awhile just to understand what it is I need to try to understand.
Excellent post! I haven't though of this much since reading sales brochures at nice stereo shops in the 70s, back when they really did try to inform the customer, not transform the customer.
