If the highs do indeed come from the center of the speaker then you could simply put a cross of duct tape over the center of the speaker on the back of the grill cloth.
That's what Stevie Ray used to do in front of the alu dust caps on his vibroverbs.
I haven't read the explanaton for the foam thing, but I have spent quite a bit of time placing microphones in front of speakers in a close mic situation. Something that I'm sure many of us have done.
My results indicate that there are a lot more highs coming off the center of the cone vs the edge. At first glance, I am not sure how the foam works. Thinking out loud - I do know that it takes mass to knock down low frequencies. Therefore, I am sure the foam is really only attenuating the upper frequencies and having very little effect on the mids and lows. So it could be that the foam creates an 'enclosure' with the speaker baffle that doesn't let the highs out due absorption.
Anyway, this has nothing to do with original post. Feel free to put the train back on the track.
I tried the "Amplifier Directivity Modifier" using the foam in front of the speaker and didnt like it on a EVM12L Thiele cab together with my #124ish clone.
However, I liked using the small circular foam plug, that I had cut out of the centre of the above, in front of the EVM as a foam beam blocker attached to a stripe of wood.
After some experimentation, I ended up removing the 40p bright cap on the master volume and using the speaker cab without and blockers and it sounded just right.
Regarding miking of the cab. For studio work, I use a Beyer M160 a couple of inches from the speaker....sometimes together with an old MD421 and neither are as sensitive to placement as a SM57.
For live work we use sennheiser 609 which hang in the mic cable close to the speaker grill. Its a 'dark' mic that like to see the speaker centre.
I tried the "Amplifier Directivity Modifier" using the foam in front of the speaker and didnt like it on a EVM12L Thiele cab together with my #124ish clone.
I tried the "Amplifier Directivity Modifier" using the foam in front of the speaker and didnt like it on a EVM12L Thiele cab together with my #124ish clone.
What didn't you like about it?
It sounded muffled and closed and the spread of sound was poor.
The flatter membrane, in comparison with a typical celestion, gives the EV a larger spread, which IMO got lost with the foam.
Mill Creek Audio wrote:It's a great idea if done right. Boogie made a 2X12 and a 4X12 in the 80's that was slanted with the top cab open back and the bottom sealed and ported. I invite anyone to go try one if you can. They made two versions, one with a Black Shadow (Celestion) on top and a Celestion on the bottom and another with an EVM in the bottom. Although I love EVM's they don't work in this cab, try the first one. It is the most balanced, widest freq response cab I have ever played, in some ways similar to an EVM in a theile cab but sounds way better with OD sounds. I have 3 of the 2X12 cabs (one with Warehouse speakers) and recently had a shootout with over 2 dozen combos and cabs, nothing even close. It sounds amazing with the Dumble type of amps as well as any other. They are a little oversized but on wheels and they are fairly light. Two local players went and found some for themselves after hearing mine, they can be found for around $300. I urge anybody looking for a 2X12 or 4X12 to check one out, the 2X12 will fill a room better than a typical 4X12 and I think you'll be suprised. I guess if there is serious interest I will measure and post plans. Yo Greg!
I've got two of these 2x12's, both with EVM 12Ls on the bottom, one with a C90 and a removable sealed back panel and the other with an open back loaded with another EVM 12L up top -- both original as far as I can tell. The former sounded very nice with my X88R into a VHT 292. I love EVM 12Ls and have been really happy with the traditional 80's MB 1x12 open backs which work well for the Soldano as well as my Bruno Super 100.
Now I am looking to try something other than the C90 or EVM up top and wonder about converting the bottom "thiele" (not sure how its spec'd) --maybe either portion are suitable for an oval port that may make a better match to my Bruno.
I wonder if an ASW KT-70 or BT-80 might work well up top with the bottom EVs -- any suggestions?
Bruno Super 100, Fender Concert II (modded), Soldano X88R > Fryette 2502, GK 250ML II...
I have received a lot of requests and interest in these half open half closed 412s. I don't know if it was the Dumble 412 that popped up on eBay a few months ago or the cabs Bonamassa plays on stage?
I've got a design drawn up...I'll be building a few of these in the next few weeks once the proto type is done. I'm gonna have to start collecting EVs to sound test the cabs!!
amplifiednation wrote:I have received a lot of requests and interest in these half open half closed 412s. I don't know if it was the Dumble 412 that popped up on eBay a few months ago or the cabs Bonamassa plays on stage?
I've got a design drawn up...I'll be building a few of these in the next few weeks once the proto type is done. I'm gonna have to start collecting EVs to sound test the cabs!!
Looking forward to pics of the first build and your report on its tonality:)
Bruno Super 100, Fender Concert II (modded), Soldano X88R > Fryette 2502, GK 250ML II...
amplifiednation wrote:I have received a lot of requests and interest in these half open half closed 412s. I don't know if it was the Dumble 412 that popped up on eBay a few months ago or the cabs Bonamassa plays on stage?
I've got a design drawn up...I'll be building a few of these in the next few weeks once the proto type is done. I'm gonna have to start collecting EVs to sound test the cabs!!
Mill Creek Audio wrote:It's a great idea if done right. Boogie made a 2X12 and a 4X12 in the 80's that was slanted with the top cab open back and the bottom sealed and ported. I invite anyone to go try one if you can. They made two versions, one with a Black Shadow (Celestion) on top and a Celestion on the bottom and another with an EVM in the bottom. Although I love EVM's they don't work in this cab, try the first one. It is the most balanced, widest freq response cab I have ever played, in some ways similar to an EVM in a theile cab but sounds way better with OD sounds. I have 3 of the 2X12 cabs (one with Warehouse speakers) and recently had a shootout with over 2 dozen combos and cabs, nothing even close. It sounds amazing with the Dumble type of amps as well as any other. They are a little oversized but on wheels and they are fairly light. Two local players went and found some for themselves after hearing mine, they can be found for around $300. I urge anybody looking for a 2X12 or 4X12 to check one out, the 2X12 will fill a room better than a typical 4X12 and I think you'll be suprised. I guess if there is serious interest I will measure and post plans. Yo Greg!
I have two of these MB 2x12; I have one with an EVM 12S in the bottom thiele ported portion and a Scumback H75-8XHP-LHDC 100 watt 8 ohm up top (instead of the C90) with the optional back panel off (it sounds too confined to my ears) and I think that sounds pretty nice so far -- just got a ASW BT-80 to swap out with the Scumback and a re-cone of an SRO ceramic on the way from ASW that I want to try in the bottom. These 2x12 can get a thump that comes close to a 4x12 -- imho.
Right now I use it with a Bruno Super 100.
Would love to hear what speaker combination yo've explored and ended up as keepers:)
Last edited by merkaba22 on Thu May 03, 2012 3:18 pm, edited 1 time in total.
Bruno Super 100, Fender Concert II (modded), Soldano X88R > Fryette 2502, GK 250ML II...
I wonder if having the bottom sealed and the top open or ported would work good?
That way you would get the bass response on the bottom and your more clear tones from the top.
Structo wrote:I wonder if having the bottom sealed and the top open or ported would work good?
That way you would get the bass response on the bottom and your more clear tones from the top.
That is the plan! I'm going to make the back panels the same size so they can be interchangeable. I'm going to make a slanted top just like the Dumble 412 on eBay. I think the slant will be a better option as the ported cab. This shouldn't be too difficult of a project as the cab will literally be 2 2x12s. Its just gonna eat up room in my shop!!
You could do a convertible split back baffle board, with a divding center, so you could just either take the top of the back baffle or switch it out with an oval ported baffle?
I'm going to cut the cab in half, carrying a centered crossbar through the entire cabinet. Two independent baffles and matching back panel dimensions will be the goal if I can get a perfectly centered dado. The slant will add a slight degree of difficulty, but shouldnt be too bad.
I plan on using 5/8" voidless birch...1/2" baffles.
It will look just like the eBay cab maverick music was selling for $25k. I can post pics right now or I would put one up of that cab
I just wonder if an oval ported back is of much use, it would look cooler for sure, but would a convertible closed back would actually give more options. I can always cut more back panels though!!
