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Author Topic: RCF L18-P200N replacement  (Read 1917 times)

Steve Litcher

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Re: RCF L18-P200N replacement
« Reply #10 on: April 22, 2021, 04:41:46 PM »

This thread is from a few years ago, but I had good luck using 18Sound drivers as replacements in my SB180R cabinets (which were shipped with L18-P200N drivers).

https://forums.prosoundweb.com/index.php?topic=159892.0

I eventually sold the SB180Rs but the 18Sound substitutes worked and sounded great.

Jim McKeveny

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Re: RCF L18-P200N replacement
« Reply #11 on: April 23, 2021, 07:52:39 AM »

This is a tough one, actually. (I'm assuming RCF no longer makes their easy to use use drop-in recone kits for the 200). Anything "modern" you install in those boxes will have more X-max and more thermal (power) handling, both of which could rapidly expose port limitations.
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Uwe Riemer2

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Re: RCF L18-P200N replacement
« Reply #12 on: April 24, 2021, 02:27:14 AM »

This is a tough one, actually. (I'm assuming RCF no longer makes their easy to use use drop-in recone kits for the 200). Anything "modern" you install in those boxes will have more X-max and more thermal (power) handling, both of which could rapidly expose port limitations.
According to the web Thomann still sells recone kits for the 18P200 Typ 2 and some recone companies in Germany list prices for KN and N versions.
AFAIR KN/N sounds more familiar to me than Typ 2, but this could be easily solved by making some old school phone ( not cell ) calls appropriate for the driver.

On the other side two 175mm round ports seems not bad for 1500W and the new mid class of 12mm X max drivers.
Tuning could be a little on the highish side, so the problem could turn into: How to make the 175mm round port longer.

Lets see if the OP wants to tell us about the TLW drop in.

And to close my little contribution: I would never even dream of putting the SW115 in 200l

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Helge A Bentsen

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Re: RCF L18-P200N replacement
« Reply #13 on: April 24, 2021, 03:48:20 AM »

According to the web Thomann still sells recone kits for the 18P200 Typ 2 and some recone companies in Germany list prices for KN and N versions.
AFAIR KN/N sounds more familiar to me than Typ 2, but this could be easily solved by making some old school phone ( not cell ) calls appropriate for the driver.

On the other side two 175mm round ports seems not bad for 1500W and the new mid class of 12mm X max drivers.
Tuning could be a little on the highish side, so the problem could turn into: How to make the 175mm round port longer.

Lets see if the OP wants to tell us about the TLW drop in.

And to close my little contribution: I would never even dream of putting the SW115 in 200l



Landed a two week installation gig so things are on hold in the diy-department at the moment, but I also noticed that Thomann sells that recone kit.
I'm considering ordering one, drop a fresh recone in one chamber and a TLW in the other for some comparison tests.

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Mark Wilkinson

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Re: RCF L18-P200N replacement
« Reply #14 on: April 25, 2021, 03:29:16 PM »



And to close my little contribution: I would never even dream of putting the SW115 in 200l

Hi Uwe, why not?
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Uwe Riemer2

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Re: RCF L18-P200N replacement
« Reply #15 on: April 27, 2021, 08:07:39 AM »

Hi Uwe, why not?
You always ask the big questions  :)

So what are the trade offs, if we put the driver in 200l compared to the 150l suggested design from B&C:
We gain extended range to the low end, which comes at the price of higher Group Delay ( and no, we cannot trade Group delay for simple delay here, we need the sound to happen now )
We lose efficiency, we lose maximum output above tuning.


But in the end you need to try out for yourself and see what you like better, or because this is a Live Sound Forum find out what is the more useful tool in SR.


« Last Edit: April 27, 2021, 08:46:08 AM by Uwe Riemer2 »
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Mark Wilkinson

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Re: RCF L18-P200N replacement
« Reply #16 on: April 27, 2021, 12:51:10 PM »

You always ask the big questions  :)

So what are the trade offs, if we put the driver in 200l compared to the 150l suggested design from B&C:
We gain extended range to the low end, which comes at the price of higher Group Delay ( and no, we cannot trade Group delay for simple delay here, we need the sound to happen now )
We lose efficiency, we lose maximum output above tuning.


But in the end you need to try out for yourself and see what you like better, or because this is a Live Sound Forum find out what is the more useful tool in SR.

I looked at group delay for the B&C at 150L vs 200L and see what you mean.   Nice catch, something I'll pay more attention to on vented boxes from now on.

Re the more useful tool for live sound..... i stick to  front loaded horn subs for live, like Labhorns or Orbitshifters, so group delay is as low as it realistically gets, i think.

My bass-reflex are for home use and playback, so i can remove group delay via a boatload of FIR....and is why I never bothered to look at it before for vented subs.
That said, I'm a firm believer in the rule that 'the best designs require the least processing'.....so thanks for the pointer  :)
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Helge A Bentsen

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Re: RCF L18-P200N replacement
« Reply #17 on: May 10, 2021, 03:13:58 PM »

Update on this project.
RCF confirmed that recone kits for 18P200N-II doesn't fit on the L18P200N frames. So reconing is off.
18TLW3000 doesn't fit inside the cabinet, there is some bracing in the way. It's off or I need to consider some woodworking.

B&C 18TBX100 fits and looks like a decent replacement in WinISD.
In terms of power, it looks like I can put in around 1KW per driver before I run into Xmax-limitations.
1.2KW if I use Xvar.

In terms of amplifier power, what would you suggest as a good target number per driver?
I've been looking at wiring 8 ohm drivers in pair and feeding them 2500W/4 ohm. I think this is "enough" for these boxes.
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Chris Grimshaw

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Re: RCF L18-P200N replacement
« Reply #18 on: May 10, 2021, 04:28:57 PM »

A Powersoft T602 conveniently puts out 2500w/ch into 4ohm  ;)

IIRC, Xvar is what B&C would like you to use. I think that's based on harmonic distortion levels, rather than the simple motor geometry that Xmax is often based on.

I usually like to test the useful excursion of drivers myself, though. I have some Beyma 15P1200Nd drivers which are rated for 9.5mm of Xmax, but you can push them to 15mm without them complaining much - their mechanical overload is very graceful, but that's not in the datasheet.


Sizing the amplifier will depend on the program material etc - you need to keep in mind that the excursion curves in WinISD are what happens when you put in 90V RMS (or whatever level you're running at) into the drivers at one frequency. That's very rare in music, but not impossible.
I'd usually like 2x the driver's AES power rating for the amplifier, but that's not always cheap or convenient.

Chris
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Helge A Bentsen

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Re: RCF L18-P200N replacement
« Reply #19 on: May 10, 2021, 04:42:36 PM »

A Powersoft T602 conveniently puts out 2500w/ch into 4ohm  ;)


Chris
Its the one Ive been looking at. Not suprised you guessed it  ;)
Agree on the 2x RMS figure, but were talking K20 or going with one amp channel per driver in 4 ohm.
Starts to get expensive and a lot of cabling/logistics.
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Re: RCF L18-P200N replacement
« Reply #19 on: May 10, 2021, 04:42:36 PM »


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