Thanks for the detailed answers. I will explain my setup.
You are right about the dipole bass correction instead of the injection channel. Since I am waiting for both a subwoofer and the Fane Studio 8M and their horn, I am using the 12" as a bass channel, and when the 2" begin, I have a high shelf that is at the lower -14dB level, where I guess your Tannoy Red is. I still believe the JBL 12" can be used as a really good injection channel, in the way you meant to. It is better that I finish the project and then we can discuss measurements, but I want to check that I have got the principles right. And also, I wanted to share my positive experience in making the JBL 12" into a dipole (which may differ a lot from your principles).
As injection channel I am dead set on a pair of JBL E-120 reconed into a
2204H. But I would be grateful if you explained how you use the
Injection channel. I read high pass filter 110dB at -14dB. This is the
same as I was thinking. You use it as a fullrange, right? Then it will
overlap with the compression drivers and they will sound very different,
while playing the same notes. It will add some soft cone speaker sounds
to the ultra detailed compression driver sounds. What am I missing? The
JBL 2204H originally had these values: FS: 45Hz Range: 35Hz-4kHz. With the huge magnet of the
E-120 has a sensitivity of about 100+dB. I will cross it lower than your
Tannoy Red, since it is not a fullrange.
I think we are disagreeing on a few things, but one big thing - that compression driver can sometimes be harsh to listen to. Sometimes so harsh I want to replace them with something else. The Minidsp active crossover unit makes this too easy, so it seems I am always fiddling with the crossover.
I do see the injection channel as something to lift up softer parts of songs. And sometimes to replace the harsh compression driver. But this is only with material that was not scored for horns. You seem to listen to a lot of classical, and here the speaker really shines. Except for Pavarotti. They really don't like Pavarotti. But I wonder what you use the injection channel for?
Right now I am listening to a new 2" Radian 750-8, that should be the same as a Radian 760PB. Horn is made in tape and cardboard (embarrassing), but sounds good. It should as it has sort of the same shape as your largest Vitavox S2 horn. According to a guy who spoke to a high-ranking guy at Radian, this driver is one of their best and I can confirm that it sounds awesome.
For the finished Macondo tribute I will use four 1" throat, 3" diaphgram compression drivers called Yamaha JA6881B, instead of my current Radian 750-8 and your Vitavoxes. They are, according to a few, TAD 4001 killers, so I should be pleased. I almost bought a Vitavox S3, but they seem so overpriced for what you get. I have not heard the Yamaha's yet.
I read about your aversion against GOTO horns, and you might be right, but I need to listen for myself first. Same goes for the Beyma TPL-150. It is not as retarded as one would think. To some genres of music every compression driver that I have ever tested will sound unpleasantly coarse. You must agree this is true to some extent. I don't think that the Vitavox S2 has some magical quality that make it stand out from every other speaker, but I might be wrong.
I did not mean I will get Goto units. If I thought S3 were too expensive I will not get a Goto unit very soon. But their horns seem interesting and those I can make myself. I made sure to match the angles of the S150 horn the exit angle of the JA6881B throat.
If the Goto S150 horn turns out to be a Japanese hype, I will stick to the Avantgarde Trio horns that I am also making in wood. Not plywood or MDF, but proper pieces of oak and pine. Not sure if these will make the Midbass horn of the Avantgarde Trio superfluous. But I want to hear how a compression driver sound in these long Goto horns. It must sound pretty special!
I will use Fane Studio 8M 8ohm for the Avantgarde midbass horn. The 8ohm version sound much better than the 16ohm for some reason. Probably because the 16 ohm are NOS.
I thought about exchanging them with Beyma 6M100 6.5", that someone mentioned sounding better, but they are not nearly as detailed. But I will have to double-check that in the finished horn in a couple of months.
Supertweeter: Home-made waveguide with Transmission Audio 50cm tall/1" wide true ribbon, transformerless with DIY Duelund resistors, and amplified with DIY Krell KSA-100 amplifier - Because it was used to power the Apogee Scintillas back in the day!
Upper Mid: 1" throat ceramic Avantgarde trio horn with JA6881B, amplifier with 45 valve amp (may be exchanged sometimes with the Beyma TPL-150 with some music genres).
Lower Mid: 1.325" throat wooden Goto horn with JA6881B + fake alnico magnet extension throat, amplifier with EL84 valve amp.
Midbass: 4" throat wooden Avantgarde horn with Fane Studio 8M 8 ohm with 6L6 valve amp ****HORN NOT IN USE YET****
"Injection channel": open baffle JBL 12" 2204H (XO: 100Hz-3kHz) with unknown amp
Subwoofer: Still unknown. 21" Beyma open baffle line array? With Hypex nCore amp? ****SUB NOT IN USE YET****
XO: Minidsp 4x10HD. Not worlds best DACS, but so handy in the beginning.
I have the Avantgarde Trio's old tweeter, the Beyma CP380/M, and the midrange speakers, called Community M200 8ohm (not the 27ohm voice coil M200A Avantgarde version). The Radian 750-8/760PB is miles ahead of the M200! The M200A voice coil must certainly be magical if it aims to beat the Radian. All the Beyma 1" are great and pretty cheap.
It is your choice if you want it open baffle or not, but I think you should try it first. The theory may say one thing but sound is physics and "We can't expect to know everything at once", like my physics professor used to say. Only reason why I am not trying the Vitavox S2 is the price.
I will have another very forgiving system for rock/metal/angry synth music: Still unknown subwoofers + DIY bass AMT + DIY AMT tweeter with TPL-150 membrane + true ribbon tweeter. For parties and movies, I guess.