2x12 Half-Back

[Alien Watts]

Can anyone describe how the 212 half back is constructed? Is the bottom ported? Is it tuned like a Thiele?

I’m wondering if it would be possible to convert my 212V recto to a half back.

Has anyone done this kind of thing? Is it a useless idea?

Thanks

 

[Joey1970]

The 2x12x halfback is more vented than ported like the 1x12 theile cabinet.

 

[Doug Doppler]

Hey Alien:

The top is completely open back and the bottom as I understand is essentially a Thiele design, but unlike the traditional 1x12model, the speaker is centered and their is a vertical port on both sides rather than just one. I've picked up three of these over the past year, so they are out there. Ideally you want the version with the MC90 Black Shadow on top and the EV on the bottom. Many cabs you'll encounter (like the one pictured below) will have had the speakers harvested. Keeping your cab as is would be my suggestion, much better for you on the resale end

Here are some sold comps on Reverb to chew over https://reverb.com/marketplace?query=boogie half back&show_only_sold=true

 

[Alien Watts]

OK, thanks guys. I will keep my cab as it is - it came with V30s, but I replaced them with a C90 and an EV and it sounds amazing. I'm pretty much using it with the JP. I now also have a MKIII green with a C90 sitting on a Thiele with an EV. I plan to put my blue stripe (head) into the combo cab when I get it back (I sent it to Mike B yesterday). Then I will either sell my green in the headshell or (probably) keep it on an open back cab which is loaded with another EV, or maybe run it through my 1960.

 

[Theresa]

This....
Was going to sell them a while back, but changed my mind and kept them. They're getting scarce. Especially in custom colors.

 

[Doug Doppler]

This....
Was going to sell them a while back, but changed my mind and kept them. They're getting scarce. Especially in custom colors.


View attachment 3334

OK, that's AMAZING. The bottom cab, in that color, JUST SO RARE. Nicely played And that head, hmm ALL OF IT = AWESOME!!!

 

[bandit2013]

I would agree with Doug on this, leave the Recto cab as is. Search for the older cabs assuming you can find any.

However, not sure if the MC90 is rated for sealed cabs as the Recto cab is not ported. The EV speaker will be fine in a sealed environment. MC90 is ported from both side of the cone, Fabric mesh as a dust cap and the core of the driver is completely drilled out with a wire mesh inserted in the hole. You can literally shine light through it and see it from the other side. In a sealed or non-ported enclosure, the cabinet would be breathing through that small opening of the MC90. The speaker that delivers the higher air pressure will win if the cone can take the abuse. That pass through port of the MC90 will make some noise that may not be musical. The closed back cabs that Mesa puts the MC90 into are ported. Just my opinion.

 

[Alien Watts]

I would agree with Doug on this, leave the Recto cab as is. Search for the older cabs assuming you can find any.

However, not sure if the MC90 is rated for sealed cabs as the Recto cab is not ported. The EV speaker will be fine in a sealed environment. MC90 is ported from both side of the cone, Fabric mesh as a dust cap and the core of the driver is completely drilled out with a wire mesh inserted in the hole. You can literally shine light through it and see it from the other side. In a sealed or non-ported enclosure, the cabinet would be breathing through that small opening of the MC90. The speaker that delivers the higher air pressure will win if the cone can take the abuse. That pass through port of the MC90 will make some noise that may not be musical. The closed back cabs that Mesa puts the MC90 into are ported. Just my opinion.

hmmm, I've never heard that before...but I will say that I have been doing it this way for years, and it is fully awesome.

 

[bandit2013]

That is fine. if it works for you great. I have never had any luck with the MC90 speakers. I have destroyed just about every one of them with the Mark V90. Dust cap usually pops off which was most of the issues. Never used them in a closed cabinet. Only the Mark V90 combo.


The widebody closed back cabinet is ported. Read the Mesa description.
https://store.mesaboogie.com/products/speaker-12-celestion-custom-90-uk-made.html

 

[rarebitusa]

OK, thanks guys. I will keep my cab as it is - it came with V30s, but I replaced them with a C90 and an EV and it sounds amazing. I'm pretty much using it with the JP. I now also have a MKIII green with a C90 sitting on a Thiele with an EV. I plan to put my blue stripe (head) into the combo cab when I get it back (I sent it to Mike B yesterday). Then I will either sell my green in the headshell or (probably) keep it on an open back cab which is loaded with another EV, or maybe run it through my 1960.

+1 for that pairing.

Did this resurrection project with a bandmates discarded custom 2x12 vert cab. Modded it for open back top. Have an EVM in the closed bottom and played around with matching others on the top. The MC-90 pairing was very good. Currently it has a Mesa v30 which is also good. Find this cab goes best with my Marks.

 

[gts]

This....
Was going to sell them a while back, but changed my mind and kept them. They're getting scarce. Especially in custom colors.


View attachment 3334

I’ve never seen a bottom (vertical metal grille) 2x12 cab before. That’s pretty cool.

 

[gts]

Ideally you want the version with the Black Shadow on top and the EV on the bottom.

No intent to bust your chops here Doug, but it might be worth noting for all that “Black Shadow” is a Mesa “brand name” they used on other speakers too including EV12L’s. You’re likely referring to the Celestion C90 as that seems to have become the speaker most associated with “Black Shadow”.

All Mesa MS-12’s were labeled “Black Shadow” too. Finding an EV with the Black Shadow label isn’t all that common but not all that rare either. Mesa also had a speaker they called “Vintage Shadow”. I can’t remember the specifics but think it was a 50watt speaker.

Fwiw in 2x12 vertical cab I prefer an MS-12 up top and an EV in the bottom. The C90 doesn’t do much for me but it does for a lot of the guys here. It all depends on what sound you’re going for.
(MS-12’s we’re made by Eminence)

 

[Alien Watts]

No intent to bust your chops here Doug, but it might be worth noting for all that “Black Shadow” is a Mesa “brand name” they used on other speakers too including EV12L’s. You’re likely referring to the Celestion C90 as that seems to have become the speaker most associated with “Black Shadow”.

All Mesa MS-12’s were labeled “Black Shadow” too. Finding an EV with the Black Shadow label isn’t all that common but not all that rare either. Mesa also had a speaker they called “Vintage Shadow”. I can’t remember the specifics but think it was a 50watt speaker.

Yeah, it’s true. I have both EVM and C90 with no labels with and Black Shadow.

Hey gts, would you make a cab like this?

 

[Doug Doppler]

No intent to bust your chops here Doug, but it might be worth noting for all that “Black Shadow” is a Mesa “brand name” they used on other speakers too including EV12L’s. You’re likely referring to the Celestion C90 as that seems to have become the speaker most associated with “Black Shadow”.

All Mesa MS-12’s were labeled “Black Shadow” too. Finding an EV with the Black Shadow label isn’t all that common but not all that rare either. Mesa also had a speaker they called “Vintage Shadow”. I can’t remember the specifics but think it was a 50watt speaker.

Fwiw in 2x12 vertical cab I prefer an MS-12 up top and an EV in the bottom. The C90 doesn’t do much for me but it does for a lot of the guys here. It all depends on what sound you’re going for.
(MS-12’s we’re made by Eminence)

Noted GTS You're 100% correct, I've amended my post. Per the VBS I found this, "For your consideration is a Mesa Boogie VS-12 Vintage Black Shadow 12" 8 ohm 50 watt ceramic magnet guitar speaker. This speaker was custom made by Eminence for Mesa back in the 80s. Works and functions with no issues. Thanks for looking!" on this Reverb listing https://reverb.com/item/18454138-mesa-boogie-vintage-black-shadow-vs-12-guitar-speaker-80s

That also explains a bit of the 'mystery' behind the 50 watt Celestions in the 'half back rack' cabs as shown in this Reverb listing https://reverb.com/item/80019741-me...k-series-model-half-back-slant-cabinet-1980-s

As you probably know, there was a period of time Eminence was supplying an EVM replacement for Boogie and you'll see those in the bottom of some of the half back 4x12s. I always wondered about the below speakers and the '50 watt form factor' be it 'Eminence Vintage Black Shadow' or what is quite possibly the Celestion alternate shown below

And last but not least a Black Shadow branded EV! That said, back in 1981 when dinosaurs roamed the earth, you had a choice of a Black Shadow, Altec, or EV. When I bought my Mark IIB from the factory it came loaded with the 'Black Shadow'. You are clearly correct that Black Shadow has appeared on numerous speakers since then. I'll do a bit more research and see what I can find out. Have a GREAT weekend

 

[gts]

Hey gts, would you make a cab like this?

A vertical 2x12? Unfortunately probably not. I have one and could measure it up for the specs to make one but it’d be an expensive venture. I wouldn’t be able to reproduce the grill either.

 

[gts]

That also explains a bit of the 'mystery' behind the 50 watt Celestions in the 'half back rack' cabs as shown in this Reverb listing https://reverb.com/item/80019741-me...k-series-model-half-back-slant-cabinet-1980-s

As you probably know, there was a period of time Eminence was supplying an EVM replacement for Boogie and you'll see those in the bottom of some of the half back 4x12s. I always wondered about the below speakers and the '50 watt form factor' be it 'Eminence Vintage Black Shadow' or what is quite possibly the Celestion alternate shown below


View attachment 3526

I’ve never seen a Celestion G12S-50 in a Mesa cab but have seen the G12-80 (which I believe was the precursor to the C90) in some Mesa vertical metal grille 4x12’s from the 80’s/ 90’s.

I’ll have to check to be sure but Celestion made a G10S-50 which Mesa used. (Note: it’s a 10” speaker; saying this just in case the ‘10’ slips past your view at first glance). There is also an EV-10M which they used too (might be a 10L, I’ll check and clarify/ confirm that one as well).

 

[user 41014]

I’ve never seen a Celestion G12S-50 in a Mesa cab but have seen the G12-80 (which I believe was the precursor to the C90) in some Mesa vertical metal grille 4x12’s from the 80’s/ 90’s.

I’ll have to check to be sure but Celestion made a G10S-50 which Mesa used. (Note: it’s a 10” speaker; saying this just in case the ‘10’ slips past your view at first glance). There is also an EV-10M which they used too (might be a 10L, I’ll check and clarify/ confirm that one as well).

I'm going to say with pretty high confidence that the G12S-50 isn't stock. MS-12, VS-12, EVM 12L, MC90, t4335 V30 are the standards and I wouldn't be surprised if a 12S made it into a few but I haven't seen it, nor a 417-8H but you gotta figure someone put them in there. You also have to think someone along the way tried an old JBL D/E/K and I would love to hear reports of it.

Paul Rivera hoarded all the 10M's and I have not seen them stock in a Mesa. I have seen the 16ohm only 10L only ever in a Mesa (doesn't mean they weren't used OEM by others), the early 210 diesel cab to be specific and I'm still waiting for a couple of them to fall into my lap. Someone has some in a closet because they are too heavy - I'm sure of it.

As you can see from the 1999 offerings there is quite a list of custom black shadows. Not all sport the sticker that makes 20 or so different speakers "custom black shadows".

I have or have seen the sticker on:
MS-12 - exclusively the dark knight with mesa colors
EVM 12L
EVM 15L
EVM 18L (pretty sure I've seen the sticker on one)
MC90

The vintage bs sticker has showed up on the VS-12, E-50 and a 10" eminence I believe at the very least.

I doubt any of the Bass custom shadows sport stickers and not sure about any 8" ones.

 

[Doug Doppler]

I'm going to say with pretty high confidence that the G12S-50 isn't stock. MS-12, VS-12, EVM 12L, MC90, t4335 V30 are the standards and I wouldn't be surprised if a 12S made it into a few but I haven't seen it, nor a 417-8H but you gotta figure someone put them in there. You also have to think someone along the way tried an old JBL D/E/K and I would love to hear reports of it.

Paul Rivera hoarded all the 10M's and I have not seen them stock in a Mesa. I have seen the 16ohm only 10L only ever in a Mesa (doesn't mean they weren't used OEM by others), the early 210 diesel cab to be specific and I'm still waiting for a couple of them to fall into my lap. Someone has some in a closet because they are too heavy - I'm sure of it.

As you can see from the 1999 offerings there is quite a list of custom black shadows. Not all sport the sticker that makes 20 or so different speakers "custom black shadows".

I have or have seen the sticker on:
MS-12 - exclusively the dark knight with mesa colors
EVM 12L
EVM 15L
EVM 18L (pretty sure I've seen the sticker on one)
MC90

The vintage bs sticker has showed up on the VS-12, E-50 and a 10" eminence I believe at the very least.

I doubt any of the Bass custom shadows sport stickers and not sure about any 8" ones.

Dear @electric mayhem and @gts - since you guys are both clearly in the know on these I'll add the I own 3 of the half back 4x12 cabs and 3 of the 2x12 cabs and spent a crazy amount of time trolling CL to find them. I do not own any of the 'rack versions' like this Reverb listing, but have seen in now two instances where they've had the aforementioned G12S-50 - a cabinet in the Pacific Northwest and this one https://reverb.com/item/80019741-me...k-series-model-half-back-slant-cabinet-1980-s which is in Florida and the guy states is, "Mesa Boogie 1980 original Mark Series model "Half Back" Slant Cabinet with old school Metal Grill front. 4x12s. All Original." The first one I saw I too figured was not stock, but after the second sighting on the opposite side of the country, I'm inclined to believe the above seller. I'll do a bit of digging and circle back on this

Per the G12-80 and C90, I recall comparing the frequency curve charts on them at one point after reading they were essentially the same speaker and per the charts coming into agreement. Thanks @electric mayhem for sharing the PDF - I've saved that to my Boogie folder

Have a great one guys (and gals) ~ Doug

 

[user 41014]

Dear @electric mayhem and @gts - since you guys are both clearly in the know on these I'll add the I own 3 of the half back 4x12 cabs and 3 of the 2x12 cabs and spent a crazy amount of time trolling CL to find them. I do not own any of the 'rack versions' like this Reverb listing, but have seen in now two instances where they've had the aforementioned G12S-50 - a cabinet in the Pacific Northwest and this one https://reverb.com/item/80019741-me...k-series-model-half-back-slant-cabinet-1980-s which is in Florida and the guy states is, "Mesa Boogie 1980 original Mark Series model "Half Back" Slant Cabinet with old school Metal Grill front. 4x12s. All Original." The first one I saw I too figured was not stock, but after the second sighting on the opposite side of the country, I'm inclined to believe the above seller. I'll do a bit of digging and circle back on this

Per the G12-80 and C90, I recall comparing the frequency curve charts on them at one point after reading they were essentially the same speaker and per the charts coming into agreement. Thanks @electric mayhem for sharing the PDF - I've saved that to my Boogie folder

Have a great one guys (and gals) ~ Doug

You're welcome. I too spent time hunting down the halfbacks.

I'm happy to be proven wrong on the G12S-50.

That said sellers on whole can not be trusted and anything posted on reverb is, well, posted on reverb where no effort is made to hold people accountable or prevent fraudulent advertising, not that I think this listing is.

I've seen "like new" that looked like it fell off a cliff, statements made after researching for 5 minutes for which people become experts in products that haven't the slightest clue. The non-archived mesa's seems to provide carte blanche for anyone to make up their own history or pass on the bad info that someone gave them honestly or to make a sale. Right now on ebay someone is insisting they have one of the first 200 boogies ever made despite serial A12xx plainly in sight and even the seller admits is 1977.

As for the halfbacks- were they even around in 1980? Maybe. But I'll bet serious money the road ready version wasn't even conceived. It's easy to date a celestion and compare against the dates of the other speakers to see if it's even possible to be original.

I got sidewinders in a road king cab. If you see sidewinders in another RK it does not mean the Rk cabs came with sidewinders. But on the other hand if you asked Mesa in the 80's to load a non-standard driver in a speaker they very well may have done it when they were still "have it your way".

 

[gts]

Since we’ve slightly veered off the “black shadow” moniker .
I’ve also seen Celestion G12-65’s in the top half of a Mesa Metal Grille 4x12. Also the Celestion “Classic Lead 80” which from what I understand is pretty much the same as the C90 vs similarity to the Celestion G12-80. Supposedly Celestion stopped making the CL-80 and Mesa still wanted it and contracted with Celestion to make the C90. Same speaker with a higher wattage. Neither the G12-65’s or CL-80’s were labeled “Black Shadow”.

These could be aberrations or they could have been installed by the owner after the fact. But I agree with Electric Mayhem about Mesa back in the 80’s being willing to put in any speaker that you’d asked them to install.