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AMP recomendations |
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ArgustusThe3th 
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Joined: 15 January 2025 Location: Brussels Status: Offline Points: 9 |
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 Topic: AMP recomendationsPosted: 15 January 2025 at 9:30am |
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Hey guys
I am building 2 G-subs for a little project... . The driver i chose is the RCF L18p300. So i need an amp that is at least 3200W @ 4Ohm per channel (2channels). I'm trying not to break the bank and i am curious what "Budget friendly" AMP's you guys would recommend. Thx in advance  . |
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Jan-2T
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Joined: 18 October 2024 Location: Belgium Status: Offline Points: 137 |
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Posted: 15 January 2025 at 10:43am |
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On the cheap: Behringer Inuke6000 or their successor
you can pick them up cheap secondhand, I bought two in the Netherlands off Marktplaats.nl As long as you don't expect this Behringer amps to give the full advertized power they are just fine doing their job. The price gap between the market segment for better amps (any pro brand) is huge... |
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Music!
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Xoc1
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Joined: 15 October 2012 Location: Devon UK Status: Online Points: 485 |
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Posted: 15 January 2025 at 8:35pm |
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So If a G Sub is about 300 litres - once we have taken out the port - braces & driver volumes - And we use the 118mm port recomended for the RCF L18P300 In theory it hits x-max 8mm at about 63.5 Volts 1000W @ 4 ohm but we dont live in a perfect world so the original 1.2KW spec still seems reasonable. Maybe able to push that a bit more dependent on what crossover / DSP settings you use. 1.6KW or so, but 3.2KW @ 4 ohms might be excessive!
Edited by Xoc1 - 15 January 2025 at 8:36pm |
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BrainlessTekno
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Joined: 20 February 2023 Location: Slovakia Status: Online Points: 381 |
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Posted: 16 January 2025 at 11:13am |
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where do you get this values from ? the original rms for l18p300 is 1000w and there are two of theese in one g-sub, they are 8 ohms so with 4 ohms its 2000w... correct me if im wrong but amp with about 3000w seems fine to me, headroom is not a bad thing am i right guys?
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BarSick / barsik soundsystem
Dont want to toot my own horn but toot toot |
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ArgustusThe3th
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Joined: 15 January 2025 Location: Brussels Status: Offline Points: 9 |
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Posted: 16 January 2025 at 11:17am |
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i am new to this so i dont really know. I did 2000w x 1.6 to have some headroom and that was 3200W @ 4Ohm per channel.
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Xoc1
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Posted: 16 January 2025 at 1:17pm |
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If you run a G Sub Sim and put 1.6Kw 3.2Kw total for each cabinet in the RCF driver the excursion is approx. double the X Max figure. Not sure what It would take in reality but that seems excessive to me. You can't just go on the power rating for the driver - You also need a high pass filter to run serious power levels.
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midas
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Joined: 27 October 2011 Location: Cumbria Status: Offline Points: 2129 |
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Posted: 22 April 2025 at 9:47pm |
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If you want my opinion, don't buy beringer.
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In bass no one can hear you scream!
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smitske96
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Joined: 16 February 2016 Location: The Netherlands Status: Offline Points: 1217 |
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Posted: 23 April 2025 at 6:33am |
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Get something from Admark, CVR, Morin etc. Enough power, reliable and affordable.
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Line Array
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Joined: 19 March 2022 Location: New Jersey, USA Status: Offline Points: 204 |
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Posted: 23 April 2025 at 6:45pm |
mind walking us through the process you used to choose this driver ? because to me the strengths of RCF are their titanium compression drivers and plastic tops, NOT their subwoofers and this driver ... RCF doesn't even call a subwoofer, because it isn't. it's a regular woofer stretched to 18" it doesn't have any of the characteristics of a subwoofer such as high BL, high MMS or high Xmax ... or high power handling. if this driver was made by another company like JBL i would call this "punishment engineering" ... JBL puts drivers like this into their entry level subs like SRX828 to "differentiate" these "PA" subs from their "prosound" subs that use better drivers. in other words the purpose of the driver is to punish the customer for not spending more money. ironically of course SRX828 is also JBL's best selling and highest rated sub because it's the only one anybody can afford. in case of RCF though they don't make any good subs IMO, and the ones sold in America are all overpriced compared to JBL because JBL makes theirs in Mexico so they can't be beaten on price by a European company in this market. look at the kind of power JBL uses in the powered SRX828SP and that's probably how much power this driver needs. it says 2000W peak for the two drivers, so less than 1000W RMS per driver. that's about right in the sense that this driver doesn't deserve any better. i think reviews for SRX828SP mention the amp not being strong enough for this sub and i'm sure that is the case but that is also consistent with punishment engineering. the reason i say this driver is like the one used in SRX828SP is because they're both stretch 18" versions of regular woofers, rather than true subwoofers. they both have 8mm xmax for example. real subwoofers have 12mm or more. the best have 17-21mm. not trying to say that xmax is the most important characteristic of a subwoofer at all, but rather that the whole driver is consistent with being a woofer, rather than a subwoofer, the Xmax simply being the most obvious metric. yes it has low FS but as i explained in another thread FS is irrelevant, except maybe for infinite baffle application. FS is just a measure of suspension compliance which might matter for infinite baffle but in a vented box other things like port tuning, box volume and moving mass will dominate and FS will not matter much unless it is WAY too high. FS does not a subwoofer make ! / Yoda voice if you already have the driver then use it, but if you don't maybe your money would be better spent on getting a true-er sub driver than on 3,200W of power. did you model this driver in software ? you should. and specifically look at excursion at low frequencies. that 35 hz RCF claims is "aspirational" ... you won't be able to take it that low at the power levels you want to use. you can perhaps use 2,000W with 50 hz tune and high pass filter, or something like that. 3,200W with 35 hz tune / HPF sounds completely unrealistic.
Edited by Line Array - 23 April 2025 at 7:05pm |
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Line Array
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Posted: 23 April 2025 at 7:40pm |
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let's do some math - i know you guys love math ! ( you hate it LOL )
this RCF https://www.rcf.it/en/products/product-detail/l18p300 has about the right FS and QTS for a subwoofer, but when compared to a REAL subwoofer like Eighteen Sound 18NTLW5000 https://www.eighteensound.it/en/products/lf-driver/18-0/4/18ntlw5000-4 RCF has: - half the XMAX - half the motor force ( BL^2 / Re ) - half the moving mass the way you know it has half the motor force is because the 4 ohm NTLW5000 has the same BL as the 8 ohm RCF which means if you put two RCF motors in parallel you will get exactly one NTLW5000 motor - same ohms and same BL. so you can think of the 18NTLW5000 as two RCFs in isobaric alignment  which by definition means the NTLW will take 2X power and work in box half the size ( that's what isobaric means ) versus the RCF ... but we still haven't addressed the Xmax ... at any given frequency it takes 4X power to reach 2X excursion which means that 18NTLW5000 will be able to mechanically handle 2 ( isobaric ) X 4 ( excursion ) = 8 times as much power as the RCF before running out of Xmax at the same frequency tune the NTLW is rated for 4,000W program which means with the same tune the RCF will only be able to handle 500W before running out of XMAX. only way it will be able to take more is if you raise the tune, but then it won't be a subwoofer anymore which it never was to begin with ... IMO anyway ... some people argue that bass fundamental doesn't matter and you only need to reproduce the 2nd harmonic in which case this RCF is just what the doctor ordered ... maybe if you have like plastic tops this RCF sub will be of value ... but it won't reach much lower than a wooden 3-way box ... though i can see the value in being able to place the sub on the ground and raise the tops above the crowd, even if the "sub" doesn't actually go any lower than a 3-way. anyway hope that wasn't too negative. in the grand scheme of things compared to some of the horrors i see this isn't bad at all. not every system has to be state of the art. 90% of people are happy with the type of "sub" you're heading towards. some people also believe that you should upgrade incrementally. that you should get something good enough, then get something better and so on. if that's you then you're on the right track. my personality is to go straight for the top, so i would personally never use this RCF driver in any application for any reason ever. Edited by Line Array - 23 April 2025 at 8:14pm |
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njw
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Joined: 26 March 2010 Location: S. Wales Status: Offline Points: 2700 |
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Posted: 23 April 2025 at 8:31pm |
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OK, first of all the l18p300 is a driver recommended for the G sub by the man that actually designed the cab, a guy who properly knows his sh*t, to say the least!
Then you state that RCF 'don't call it a subwoofer, because it isn't' and then proceed to post reasons why you think it isn't???
Then you compare the l18p300 to some JBL oem woofer that I can't find any specs for apart from it has a 3" coil... And then we're onto modelling software.. Again... It may say that the RCF won't take full power at low frequencies and I don't doubt that, I also don't doubt that the same applies to many other speakers. And bollox to the software anyway, come back here when you've actually heard, with your own ears, a G sub loaded with l18p300's and say it doesn't work. And then the RCF driver gets compared to a driver that costs 3x as much and what a surprise, the more expensive one is a better driver! ....Jesus H Christ... I've just seen your edit, if you seriously think an l18p300 loaded G Sub won't go any lower than a full range top, do you actually have ANY hands on experience with pro audio...? I'm suspecting not... Edited by njw - 23 April 2025 at 8:39pm |
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KDW32
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Joined: 09 April 2010 Location: Green Hell Status: Offline Points: 770 |
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Posted: 23 April 2025 at 8:32pm |
Ignore Line Array he literally just speaks tripe. That rcf is very good driver with decent magnet. It's recommended for the gsub. It's also very good in the wsx horn but superceded by B and C 18tbx100 The G Sub is not the most efficient reflex design but it's a perfectly ok all rounder. You may find a more efficient design for that driver. The G sub is a big box and you might find single 18s easier to move and get through doors. .i have friends in France that have 8 G subs with the rcf l18p300 and they definitely do the job. Good luck.with project and please come back with build photos.
Edited by KDW32 - 23 April 2025 at 8:33pm |
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ArgustusThe3th wrote: