A few comments on the EVM12L, in reference to the black label option: I was in awe of this speaker. My first attempt of its use was with a Mark IVb. It was probably a good move as the MC90 was due for retirement (voice coil was beginning to sound scratchy). The EVM12L did not exactly fit inside the combo enclosure as there was no room to remove the power tubes and nearly as difficult to replace preamp tubes when mounted to the back side of the baffle. The trick was to front mount the speaker. Character at lower volumes tend to be dominated with the lower frequencies. At moderate to high volume the speaker excels beyond belief. The Mark IVb is similar to the Mark III such that there is not much of an adjustment with the volume controls before the onset of full power. However, there was a difference when the same speaker is installed with a Mark V combo. The clean channel took on a different tone with bold low end and pristine top end. Under moderate distortion with CH2 or CH3 the top end chime seemed enhanced (sometimes a bit too bright) along with in your face punchy lows. Mid frequencies would also emerge in the sound spectrum. It is an amazing speaker but not for everybody. Before I converted the Mark V to a combo, I replaced all of the V30's in my recto cab with the EVM12L BL. I was trying to escape the beaming effect of the V30 as well as bass flub that was hard to dial out ( more prone with the Mark IVb when the 412 was used). I thought the EV was the greatest speaker and was definitely becoming biased against the V30. That was until the RA100 came on board. Sooner or later I bought a new Recto cab just for the RA100. The itch got worse and I decided to get the amp I wanted (Roadster) but came home with the Mark V instead. The EV loaded 412 would ring out grinding power chords with ease that were strong enough to strip the enamel off your teeth. It did not take long to realize what I was lacking in the sound stage, fluidity and response. The EV is not bad for a guitar speaker but I believe it would serve better for sound reinforcement. A/B comparison between the new Recto cab and the old one with the EV was disturbing. At first I did not like the Roadster thought the new cab and thought the EV was a better choice. Still I felt something lacking in the mix. The old V30's were mounted in a inexpensive traditional size cab and was used with the RA100, before I had the funds to get a new Recto cab. Once I a while I would pull it out of storage (spare bedroom) and use it with the RA100 for a full stack. Had to try the same with the Roadster and that is when it hit me. I opted to use the traditional size cab loaded with V30 with the Roadster and put the EV loaded cab into storage. A few weeks and I did not miss the EV cab. I eventually decided to restore the 15 year old Recto cab by returning the original V30s to their final location. At the moment I do not have any 412 cabs loaded with EV's. One exception, the converted to combo Mark V has and EV loaded into its cavity with a sister cab and another EV. It has its good side and bad. At volume levels to keep up with either RA100 or the Roadster, the two EV speakers provide enough volume of air to nearly drown out the other amps. The bad side, the bass player would be upset as the EV really dips into the lower frequencies quite well. (note: I did power the 412 cab with the EV speakers with the Bass amp, did not work all that well). I am currently moving away from EV's. If all you do is open chords and nothing else great. If you palm mute a lot, the EV may not provide what you are looking for.
However, since they have a high power rating, a 1x12 extension cab (ported or not) would add a bit of depth to your sound when used with a V30 loaded 412. Not sure if my affair with the EV speaker is over or not. I do have another amp on its way (Stiletto Deuce) so the marriage may not be over yet. I am going to change the speaker of the Mark V combo to something else. (Jensen Black Bird, if it sound anything like the WGS Night Hawk before I burned up the voice coil using it in the Mark IV combo I will be happy).
One last note: For some reason or another, I have found the EV to be sterile in its reactive character unless you are pushing the volume levels up. It took me about 3 years to come to this conclusion though trial and error and probably lost most of my hearing in the process. The EV will not cure a treble dominated amp like the Mark V, what it will do is compensate (lack of a better term) with bass enhancement and not so aggressive mids.
