Yeah, one of my two main gripes with the Altec duplex series. It was fine back when recordings were -24 dB/40 Hz, but circa '71 onward? I think not unless something is done to severely limit it.
That said, to date, of the few that have built truly large [Vb = Vas] MLTLs tuned to the 20s Hz Fs 604s, only one added an Altec 416-8B woofer to supplement it for [mostly] uncompressed recordings AFAIK, so YMMV.
Even with all the caveats, it is still good as a reality check.
e.g. the point I made, that a 6" is able to play 15dB louder, if highpassed at 200Hz, than a 12" playing to 40Hz.
That gap in output is huge.
The 12" could be in a vented box, made of unicorn bone, sprinkled with fairy dust - doesn't matter.
The (highassed) smaller driver will have more SPL capability.
Supposedly the 12HX230 should be better for Hi-Fi use but I doubt it...
Also nice price. Much cheaper than I can get it for.
While I have you here. Anyone has any info what α does Acousta-Stuf have? I can't find any info inside the parts express datasheet.
Or at least anyone has any info on the desired α of the materials used to absorb sound inside the cabinet?
Those delta 15dB is from mechanical perspective only right? Introducing sensitive and electrical power handling I’m not sure about the same is longer valid. I’ve burded quite a few speakers in my days in hobby PA/DJ and it’s usually the mid that goes first, and usually electrically / melted coil. I know it was a good party if the midrange smell. I get your point though. A large two way / coax definitely have limitation in mechanical distortion at loud levels running full range, most large coax are meant to be used for wedge monitors with limited low end.. But I think sensitivity makes up for it in home use allowing to play full range especially at decent levels. I don’t yet know though, it is what I’m trying to test with these project. I’m sure a sub is needed for full range full power. Active 80hz like home cinema seems like a good idea. But before going down that route I want to test a few 12” coax in 70l and measure what it’s cabable of in terms of range, power, distortion. In a year maybe have more data, I work slow 
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Hi,
TLHP's pricing is competitive though I don't have any experience dealing withthem yet. Coincidentally, I was also looking at the 12HX230 and saw this from my googling adventure the other day:
https://s3.amazonaws.com/psma-website-assets/Faital_Coax_Dipoles_Plans.pdf
TLHP's pricing is competitive though I don't have any experience dealing withthem yet. Coincidentally, I was also looking at the 12HX230 and saw this from my googling adventure the other day:
https://s3.amazonaws.com/psma-website-assets/Faital_Coax_Dipoles_Plans.pdf
Between its specs and this doc, maybe can calculate it: (PDF) Sound Absorption Coefficients of Micro-fiber Fabrics by Reverberation Room Method
Yes, just excursion.
This is always the limiting factor in my applications.
Yes. So if you are looking at two coaxial drivers, where diameter etc is equal:
a) is $150 with 3mm x-max
b is $800 but has 8mm x-max
...if you buy the cheap driver and high pass it at 200Hz, your x-max limited SPL will be a colossal 20dB higher than if you buy the expensive driver and run it down to 40Hz.
How long ago? Passive x-over? HOw was it built / tested?
Is there a possibility that too much LF was getting to the mid?
My guess is that if you ran the same "test" with a cheap modern active X-over, the mids would probably be OK.
Well this have happened many times on different systems, all long ago in my rave days. Sometimes with passive, other times active. And yes it might very well be that we crossed too low with weak first order but it could also be a sensitivity issue for 4-5” midhorn trying to keep up with dual 12” midbass and 18” subs. I’m just saying the mids have been the weak link in most of my experience.
Anyway I see the celestion back in stock on parts express. Hope that means it will show up locally too as well so I can get on with this project.
Anyway I see the celestion back in stock on parts express. Hope that means it will show up locally too as well so I can get on with this project.
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may i ask why you are interested in the celestion driver? to me celestion coax's does not look very good, mostly so their tweeters, to bad the are so few 3rd party measurements
FTX 1225 Monitor, Messungen
Test Bench: Celestion FTX0820 8-inch Coaxial Woofer/Compression Driver | audioXpress
Well it’s cheap (locally) and looks rugged. I agree the tweeter resonance look ugly so Im still waiting OPs feedback. I’m just playing around with various projects stepping up in smaller steps from the beta 12. I like to compare by listening. Eventually will probably end up with kappas or BMS or something but not before I have gained the proper experience trying to make the most of cheaper things, learning to measure and design proper crossovers etc. it’s a long road ahead of fun coax projects. The ones that doesn’t perform well on music will end up in my future home theatre
There is also a backup plan with the use of 12” PA coax. If I conclude years from now I hate it I can just don’t use the treble and buy a 5” mid and a dome, or some other horns and go from there with 3-way (not using the coax treble but only the bass driver), just making sure the baffles have space for that. I’m gonna build quite a few 40x60x40cm / 70l boxes.
I have today Eminence Beta 10 and 12.
Compression drivers APT50, ASD1001 and PSD2002.
Pre-built crossover PXB2:2K5CX and variable LPAD.
With that crossover I find that Beta 10 and PSD2002 combo sounds "best" (in my box and room that is). Beta 12 and ASD1001 is also quite good but needs a different crossover and bigger box. Actually Beta 12 and PSD2002 is also very good but need maybe even more attention to crossover. APT50 have not been a success to me with any of the drivers but again could be crossover.
2kHz area doesn't sound very good on the 12 with any of the drivers and this standard crossover, I think I need a 18dB LPF at 1500Hz and 12dB HPF. All this is by ear. No measurements at all. And in a difficult concrete room of 10m2. So I wont bother building crossover before I have learned measurements. I rather start another parallel project
I am expecting all the same problems with the Celestion so the only way for me forward is to learn measurement and start designing my own crossovers. The Beta 10/PSD2002 combo is the most complete right now but Id like to start yet another project with the Celestions and customer crossover. We are looking for a bigger house to store all these projects: living room, studio, basement - I will build at least three pairs and possible a sub for the basement home theatre but that will take a few years I guess.
Oh I forgot to mention I also bought a Selenium DT220Ti but that was not a success in this setup. I wonder if its something wrong with it. It has a high pitch ringing sound around 2,5kHz (found out using a software synth with pink noise and a graphical equalizer). This was both with and without using crossover. Could be something about the combo of the Beta horns, IDK.
Edit: I need to highlight that I am not very picky. I like high dynamics, strong bass, clear treble and big sound (PA). I listen to electronic music primarily. I doubt these coaxes are for everyone, I think vocals and guitars is probably a problem when there is such uneven response around 2kHz. I'm sure the higher priced coaxes may be more "hifi" but I'm not there yet to invest that much. I like cheap things that are tailored to my need. Ive never been happy with al-round tower and bookshelf hifis not nearfield studio monitors. I'm much more happy with these Eminences, they bring back the live sound I missed from my rave days.
Compression drivers APT50, ASD1001 and PSD2002.
Pre-built crossover PXB2:2K5CX and variable LPAD.
With that crossover I find that Beta 10 and PSD2002 combo sounds "best" (in my box and room that is). Beta 12 and ASD1001 is also quite good but needs a different crossover and bigger box. Actually Beta 12 and PSD2002 is also very good but need maybe even more attention to crossover. APT50 have not been a success to me with any of the drivers but again could be crossover.
2kHz area doesn't sound very good on the 12 with any of the drivers and this standard crossover, I think I need a 18dB LPF at 1500Hz and 12dB HPF. All this is by ear. No measurements at all. And in a difficult concrete room of 10m2. So I wont bother building crossover before I have learned measurements. I rather start another parallel project
I am expecting all the same problems with the Celestion so the only way for me forward is to learn measurement and start designing my own crossovers. The Beta 10/PSD2002 combo is the most complete right now but Id like to start yet another project with the Celestions and customer crossover. We are looking for a bigger house to store all these projects: living room, studio, basement - I will build at least three pairs and possible a sub for the basement home theatre but that will take a few years I guess.
Oh I forgot to mention I also bought a Selenium DT220Ti but that was not a success in this setup. I wonder if its something wrong with it. It has a high pitch ringing sound around 2,5kHz (found out using a software synth with pink noise and a graphical equalizer). This was both with and without using crossover. Could be something about the combo of the Beta horns, IDK.
Edit: I need to highlight that I am not very picky. I like high dynamics, strong bass, clear treble and big sound (PA). I listen to electronic music primarily. I doubt these coaxes are for everyone, I think vocals and guitars is probably a problem when there is such uneven response around 2kHz. I'm sure the higher priced coaxes may be more "hifi" but I'm not there yet to invest that much. I like cheap things that are tailored to my need. Ive never been happy with al-round tower and bookshelf hifis not nearfield studio monitors. I'm much more happy with these Eminences, they bring back the live sound I missed from my rave days.
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wow, sounds like you have a great future with a new house and new projects
the issues at 2khz, is that a lack of output level or driver dist?
i have no experience with dt220i but what i have read, many seems to not like that driver, but it still seems to be popular
i have built new smaller cabs for my 12cx's, but they ended up being too small, but they should work good with the 12" celestion, hence my interest
the issues at 2khz, is that a lack of output level or driver dist?
i have no experience with dt220i but what i have read, many seems to not like that driver, but it still seems to be popular
i have built new smaller cabs for my 12cx's, but they ended up being too small, but they should work good with the 12" celestion, hence my interest
We have struggled to find a big enough house to host all my planned projects though, I'm afraid somethings got to give. Yes I am also curious if the Celestion works better in the smaller cabs I have already (about 50l), but as long as they're out of stock I'm out of luck. Same with house lol, out of stock.
The problem at (assumed) 2kHz is probably due to the crossover not made for the 12". Its lacking clarity and its very clear once the HF takes over. The 12CX have kind of dark sound to it if that makes sense? With this crossover at least. I'm sure its possible to fix with tailored crossovers. Someday. If not they are good enough for surround, lots of punch and body and I just love these compression drivers in short omni-directoral horns. Not sure why I ever thought horns as compression drivers was bad for home use.
Anyhow I wont do much right now. Covid lockdown makes it all very difficult. Drivers out of stock, woodshop closed. Im just planning. And of course the fact that I have no space in my current home for more DIY. Just glad I got the Betas up and running now.
And of course waiting for OPs feedback on his purchase
The problem at (assumed) 2kHz is probably due to the crossover not made for the 12". Its lacking clarity and its very clear once the HF takes over. The 12CX have kind of dark sound to it if that makes sense? With this crossover at least. I'm sure its possible to fix with tailored crossovers. Someday. If not they are good enough for surround, lots of punch and body and I just love these compression drivers in short omni-directoral horns. Not sure why I ever thought horns as compression drivers was bad for home use.
Anyhow I wont do much right now. Covid lockdown makes it all very difficult. Drivers out of stock, woodshop closed. Im just planning. And of course the fact that I have no space in my current home for more DIY. Just glad I got the Betas up and running now.
And of course waiting for OPs feedback on his purchase
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