RCF LF18X400

Probably it can play even from 40Hz with -3dB. It's great speaker for 186 or 1850.

I have some questions. I don't know how to modelize 186 and 1850 horns in hornresp, in particular to calculate the path lenght and the throat chamber. Rog said that 186 horn offers a hi-fi bass, so I expected a more extended LF response, but from the plots I saw that 1850 horn has a lower f3. That's right? 

If you read further you'll see he talks about the fact the 1850 has a snappier transient. It's not so much to do with extended LF response as the fact that it doesn't respond as fast as the 1850 so sounds 'smoother'. Kind of like dripping syrup in your earhole.

There's a provided spec for drivers for the 1850horn, EBP over 125. The FAQ covers how to calculate EBP.

I did say that a driver that would be good for use in a horn usually has an EBP (efficiency bandwidth product) of greater than 130. This is not the rule though, it is only a guide. EBP is Fs divided by Qes and gives a rough approximation of how well the motor system can control the cone. It doesn't always follow that high EBP figures automatically make the driver suitable for horn loading, there are so many parameters that dictate which driver to chose for a particular horn and so many different horns for different jobs.

The 18LX400 only has an EBP of 96.

Also don't forget there's no such thing as a cabinet plot, it's a plot of a specific driver in a specific cab. If you change the driver out, the response of the cab will change too. Don't you just hate math

The L18P300 is mentioned as suitable for the 186, so use it for a baseline and compare the 18LX400 to it. Good luck with the hornresp idea.


Edited by rastaman

fs is not really important in a horn driver as I recall. You want a good strong BL (motor strength) and a fairly rigid structure,  a nice low Qes.

Rog says in the FAQ EBP > 125 and Qts < .28 for a good horn driver, the Qes on the LX400 is .27 just within it, but you could maybe do better. That said the L18P300 has a lower BL and a higher Qts. Weird.

Looking through the RCF range (I assume because it's in Italy?) I see that all the driver specs for 18's are similar, the one that stands out is the L18S800, it has a slightly higher fs which is generally better for a horn. Although it's Qts is .29 which is one over Rog's magic .28 it has an EBP of 130 which would suggest it could get quite loud in an 1850 horn. It's BL is also slightly better than the LX400. As it's Qts is still lower than the P300, I think it could be a contender, though it's no PD1850. However if you can afford it (I assume neodyium drivers are more expensive) the best looking one is the LF18N402. Nice low Qts of .24, an EBP of 150, and a BL of 29. Efficiency is a little down on the L18S800 but I think it would handle more power which should make up for it.

This is going to be one of those things, once you can get it modelled right you'll have lots of fun modelling all the different drivers.

Ask about however, don't take my word for it, I wouldn't




Edited by rastaman

sence iv been reading along, my guess is, the graph for this "1850horn" is probly modeled for multiple horns.

*if anyone hasnt had a go at it, the post about a punisher horn in "general" tells why i dont know a hole lot about horns yet...*

but to my knowledge as for now, a singel horn wont get you deep pounding bass if im correct? and so there for you would need multiple horns or a "stack". and also that i know of after 2 hours of reading. yes a good 125 and up EBP , 22.5BL and up, low QTS. to what i see so far toying with hornresp. i do see a higher Fs helps a bit, but not much.

my sugjestion would be a P300. cost effecient and after having a look at this 186horn seems that it would do fine. i think i would use a eighteen sound 18W1000 for the 186horn though, cost less (one) and two has a higher EBP and BL and handels a good 1000watt rms

hey wow, those are nice haha.