I dont think you can hear it. This is Autotech Eos-15 with 1,5 inch throat and 18Sound 1,4 inch driver. You can see the diffraction around 13000 Hz:
It's back in stock.
Also, if you want to go lower in freq. with this driver and have good off-axis results then I'd suggest this waveguide:
https://eminence.com/products/sst1
(disregard the statement that the waveguide is screw-on, it is BOLT on; their website designers are idiots.)
You can see the results with Peerless's less expensive (discontinued) smaller diameter driver here:
https://audioxpress.com/article/peerless-by-tymphany-dfm-2535r00-08-compression-driver
Turns out it's more close to 1.4" throat entry. I measured it with vernier scale and the diameter is around 1.36" - 1.38x" ...... indeed it's a toy.
FR from 2 DCX on horn. Gated, volume not calibrated.....also not at a good measurement condition.
The mounting of this horn however has some room to shift...that influence high frequency quite a bit.
Does not look bad at all. Did you short the leads of the unused "way" when taking these measurements ?
Regards
Charles
Regards
Charles
I connect both HF and MF to the 1200AS2 amplifier during measurement so I think it's close to short condition.
Output impedance rise to 50mOhm @ 20kHz from its datasheet.
Output impedance rise to 50mOhm @ 20kHz from its datasheet.
Because the "unused" diaphragms could show resonances that it wouldn't if its respective coils was shorted by an amp as usual. There was someone on a German PA forum who measured the DCX464 and some BMS and who repeated the measurements because he first forgot to short the driver that he wasn't measuring. I can't remember by how much the measurements differed. But they did.
Regards
Charles
Regards
Charles
Thanks. Shorting by a tube OT, is that enough? The output impedance is higher than with silicon amps.
The throat (adapter) is secured with hex screws, just like the 18Sound 2" drivers I assume? I've only had the 1.4 in my hand.
yess same kind of hex screw fixing , i have at first ordered the 1.4inch model with the 18sounds adapter but it doesn't fit well with the RCF 850ND as there is still some little space left between the adapter and the driver even with the foam on . so i return them and take the 2 inch model directly..
i 'm still waiting my wood tratrix Horns as it takes longer time that i expected to get them from LMH , but even without horns the sound of these drivers seems very good , not as extedend as the 1inch Faital HF108 wich is normal but sounds very smooth 🙂
i 'm still waiting my wood tratrix Horns as it takes longer time that i expected to get them from LMH , but even without horns the sound of these drivers seems very good , not as extedend as the 1inch Faital HF108 wich is normal but sounds very smooth 🙂
nothing to criticise , i just needs to go to 600HZ . for the moment i use my HF108 as tweeter from 2K and paper cone driver from 400 to 2K , my goal is to replace it with a big round horn from 500 HZ with the RCF 850. if can go 2 Way like that i will sell my HF108s and if not i will keep it 3 way and use them from 8K as pure tweeters 🙂
Despite some breakup resonances, the RCF ND850 is definitely among my favorite drivers.
I've only heard the driver in 2-way systems which all sounded really, really good in the mids/highs.
I've only heard the driver in 2-way systems which all sounded really, really good in the mids/highs.
A Tractrix 350 Hz seems the best compromise between loading and directivity.
With a 2" throat, the horn isn't extremely deep (about 23 cm, excluding the throat adapter), which confines the trumpet effect somewhat.
My own experiences are congruent with the extensive research of Philip Newell and Keith Holland in the 1990s.
I disagree.
Tractrix loading is poor.
Tractrix directivity control is also poor.
Tractrix theory is wrong (constant radius wavefronts is a physical impossibility).
"Trumpet effect" is completely unrelated to horn length.
Newell and Holland inferred this wrongly, and their own inference is contradicted by their own admission in their published research that a longer Fostex wooden radial horn had the least "horn/trumpet sound" of all tested devices.
Agreed. After believing all the trax hype nearly 20ya, I paid a substantial amount of money for some very large round traxs to be turned up and they were horrible compared to the A290s they were supposed to replace.