Right, the smaller the better, a 1" exit driver is a beaming direct radiator with a falling response above ~ 4316 Hz, so to push this point up to 20 kHz requires a ~0.216" exit and depending on how close you want its off axis response to blend to the mids-lower HF horn through at least the XO BW may require a WG be added to the super tweeter (ST) to control its directivity to a lower frequency.
GM
GM
GM said:
But some 1" drivers have a flat response more or less all the way up to 17khz. Anyway I think it will be better even just to use mY titanium RCF from 500hz to 4000hz and then the 1" compression driver with horn. I think that is I wnat to go from 4000khz I need a 1" compression driver because the Fostex tweeters wont go that low. The question will be what approach is better?
1. 2" compression driver/horn from 500-4000hz and 1"compresion driver/horn from 4khz to 20khz
or
2. 2" compression driver/horn from 500-8000hz and a Fostex Bullet Tweeter from 8000hz to 20khz?
This question is assuming that the 2" can go to 8khz wihout problems.
Alan Brain
inkasound said:
I vote for number one.
My reason for that is that you want to allow the crossover to rob as much of the troublesome energy out of the 2incher as possible.
I havent heard the DE25 that i know of/can remember, but some googling only showed positive responses.
It has also won some german hifi awards so hopefully it wont be too bad...
However, that one only extended to approx 17-18KHz, which is slightly above what an 1incher is recomended to cover. So you need to decide if that is enough for you, or if you want to add something else above that.
electroaudio said:
Thanks for the feedback. Could you advice me on another 1" compression driver for that tasK?
electroaudio said:
So, in any case is always better to use a 2" only from 400 to 4-5khz, in its comfort zone, right?
As for the 18khz extension of the 1", mostly all 1" are like that. The 2" that reach 20k more or less have the same slope at 18khz that the 1" inchers, with the difference that the 1" reach there with less trouble.
The supertweeter will be the last step. If the Test with the titanium RCF from 400-4000hz doesnt work so well I will change it for a Community M200.
ALan
inkasound said:
Only on axis and with the right WG which is why they typically don't publish PWT or polar plots.
And why I said they may need a large WG to blend them, i.e. load them to a lower frequency.
Assuming this is for HIFI and not prosound:
#3. Sell/swap the 2" for 1.4" to ~5 kHz and use one of the several Fostex or other brand choices for the top end.
If you insist on a 1", then I recommend these, ditto the 1.4": http://www.greatplainsaudio.com/hf_drivers.html
GM
GM said:
Thanks for the advice. Yes, its for Hi Fi. If I do it that way I will have to cross the Fostex tweeter around 7khz no lower. That's the safest lower area to start using it.
I prefer to use a a bigger diaphragm for the frequency range between 400hz and 5000hz, I believe the bigger diaphragms sounds fuller, the RCF has a 3" inches diaphragm and the Community M200 a 2".
I was going through the great plains website and the 390 looks interesting, it goes down all the way to 300hz and its a phenolic diaphragm. Sorry they dont have frequency response graphs.
Alan
Alan
inkasound said:
Unfoutunately not, my own construction consists of jbl 2410 with homemade diagraphms.
Maybe you would be satisfied with something like JBL 077 or EV ST350A ontop of your 2incher?
You can use them as far as your driver/horn will meet your personal requirements.
However, the most common range for a modern 2incher is from 1-1.5KHz and up. But in the old days it was most common to use that throatsize between 500/800Hz and 8KHz (1wavelength=6700Hz).
I actually work sometimes with six M200 drivers, however they are buried inside community SLS960 boxes, so i cant really say what is what of the sound from them.
But SLS960 also use an 1incher ontop of the M200.
tinitus said:1.4" and 2" from FaitalPro both seems to have a 75mm voicecoil, and the same goes fore Beyma too
Does that mean they have the same diaphragm, but only different throath, and compression ratio
Maybe not the same diagraphm even if it very likely is possible to mount them in eachother.
JBLs consertsystem HLA has an 1incher ontop where it is possible to use a JBL 2inch diagraphm, and probably a lot of other diagrams too since coilsize+throatsize for some strange reason is rather standardized over different brands.
-The best 2incher i have heard actually was a Emilar driver with an altec metallic diagraphm on a CAAD waveguide.
inkasound said:
You're welcome!
Says who? Certainly not Fostex.
Well, up to a point I agree, but I've yet to hear from anyone who's been exposed to Altec's 1.4" drivers XO'd at even 300 Hz on the appropriate size horn that felt it needed a bigger driver because it didn't sound 'full' enough. I mean if that's the case, then compression horn load a 6" or 8" cone driver and XO it to a 1" or one of the super tweeters when it starts beaming too much for you. The main difference with larger exits is the horn can be shorter, i.e. more of a WG than compression horn, with the trade-off being a lower HF corner, ergo more of its response is just from direct radiation.
The 390 is essentially a re-badged Altec 290, so due to its phenolic diaphragm is nominally flat to only 7 kHz on the right horn. For 'robust' sounding mids from a compression driver you can't beat a phenolic diaphragm. Too robust for me in a HIFI app. They were designed to slam vocals through a perforated screen at high SPL to the far corners of a large theater. I prefer the more civilized tone of the 399's wide BW diaphragm.
GM
tinitus said:
They are horn (flat) flange mount with both a three and four bolt pattern. Being a 1.4" exit there's probably not many (if any) new horns available for them to mate to without an adapter though. Altec Mantaray CD horns show up regularly on epay at reasonable prices, so that's another option.
GM
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