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G-Sub : RCF L 18P300 vs RCF LF18G400? |
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djjunglejym 
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Joined: 11 April 2009 Location: Santa Fe, USA Status: Offline Points: 5 |
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 Topic: G-Sub : RCF L 18P300 vs RCF LF18G400?Posted: 11 April 2009 at 10:16pm |
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Can anyone help me? I want to build the G Sub, but was going to use the RCF LF18G400 rather than the RCF L 18P300 due to the extended low frequency response of the RCF LF18G400 (25Hz, as opposed to 35Hz for the RCF L 18P300).
However, using WINISD to model the box and plot the frequency response, it looks like the RCF L 18P300 has a steeper response curver at lower frequencies than the RCF LF18G400!
How is this possible? It is my first time using WINISD, and I may be doing something wrong, so can anyone tell me if these response curves are accurate, and which is the best of these two drivers to use in the G Sub?
I am planning to use two G Subs in small performance spaces only, and accuracy and extended low frequency response are my primary concern, with high power handling capablity my secondary concern.
Many, many thanks!
DJ Jungle Jym
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ceharden
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Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11776 |
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Posted: 11 April 2009 at 10:59pm |
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The low frequency extension depends on the cabinet and the driver. Just changing the driver for one with a lower resonance will not increase the extension unless you retune the cabinet to take advantage of it.
Can you post a picture of the plots so we're clear what you're referring to please. |
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mobiele eenheid
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Joined: 15 August 2004 Location: Netherlands Status: Offline Points: 1568 |
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Posted: 14 April 2009 at 8:17pm |
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The resonance frequency of the L18G400 is 28 Hz, 33 Hz for the L18P300. However that says something about it's resonance frequency. A driver with a higher Qts will have less trouble getting flat to it's Fs then a low Qts driver. It's almost never a single T/S-parametr that tells you the story, it's the combination, WinISD Pro visualises that information. And then there's the tuning of the cabinet as Ceharden mentioned.
Best regards Johan
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djjunglejym
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Joined: 11 April 2009 Location: Santa Fe, USA Status: Offline Points: 5 |
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Posted: 14 April 2009 at 10:53pm |
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Thanks Johan!
I think what the visualization is telling me is that the RCF L 18P300 is the more appropriate driver for this cabinet...
What is the RCF LF18G400 best suited for, and what justifies the extra cost of the driver?
If you were building a G Sub, which would you use?
Does anyone have any feedback on other direct radiating or reflex subs that would work better in small performance spaces and offer extended and accurate low frequency response?
Sorry for all the questions, but I don't want to mess up on my first build!
Thanks for anything you can offer!...
Jungle Jym Edited by djjunglejym - 15 April 2009 at 12:01am |
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Calitri
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Joined: 02 November 2004 Location: Finland Status: Offline Points: 132 |
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Posted: 15 April 2009 at 6:52am |
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The P300 is a more open sounding driver in a reflex and manifold-bandpass loading and it sounds very nice in simple compact relfex bin. The G400 is a bit more rougher driver for a bandpass and horn loading. They're almost the same by parameters but the G400 has a stronger and a thicker cone so it can handle a bit more stress. Also the motor is a bit stronger along with the x-max and x-mech. The X400 is the best of them all as it has the Muller cone but it's also quite pricy.
If you want to have a bin that does 30 Hz properly, go for the G400. If you want a normal general purpose bin that does 35-40 Hz and a small size, go for the P300. This is just a very rough rule of a thumb for their usage but this way you get the best out of them.
The G-Sub is bit of a problem as it's size makes it sit between the two so it's a more personal preference rather than an absolute fact. If you like more open sounding drivers, like I said, go for the P300s.
On a side note, if you're planning to build horns like FK1/USB or WSX, I'd go for the X/G400s for the cone and motor strength.
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djjunglejym
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Posted: 16 April 2009 at 12:50am |
 Thank for all your help guys!
I think I will go ahead and make the build using the RCF L18P300's. They seem like the best combination of low frequency reproduction, power handling and price for this cabinet.
I will tweak the response curve (in WINISD) to get response a little lower, while still keeping to -2dB from 60 to 100Hz (Don't want to lose to kick drum, so I'll EQ this to level in the rig!) and modify the cabinet according to WINISD.
The other drivers we have discussed seem to want a MUCH larger cabinet to get as low, so this seems like the best option.
Couple last questions... Does setting/mounting handles into the sides of the subs compromise the integrity of the cabinet or the sound quality, and does anyone know where to buy speaker grills this size (536 x 1100mm)?
Thanks!
Jungle Jym   Edited by djjunglejym - 16 April 2009 at 12:53am |
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Glenn
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Posted: 16 April 2009 at 3:39pm |
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Be careful designing the cab to go any lower. The Gsub with the rcf driver already goes lower than almost any other reflexes -3db at 35hz iirc. If you want the impression of loud low bass that is 40-45hz.
By designing the cab to go lower you are losing valuable spl in the 40-45 region and also to your detriment a lower tuning will increase the cone excursion in this region so you can't eq it back before exceeding xmax. Tune too low and you could end up with a cab that you cant hear bass from other than new noises created by vibrating walls ceilings etc. I am exaggerating a bit but you get the idea. Also I think of kick as 80-120hz though I may be wrong in that assumption.
Edited by Glenn - 16 April 2009 at 3:46pm |
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malina
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Posted: 16 April 2009 at 5:45pm |
Does this refers to G401? Never seen G401 so would like to here comments on using it in WSX. Better then P300 or not? Thnx |
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djjunglejym
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Posted: 16 April 2009 at 6:54pm |
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Thanks Glenn! I hadn't thought of that!
My inexperience is showing, any other feedback anyone?
JJ
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Calitri
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Posted: 17 April 2009 at 7:06am |
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I meant the original x/G400 driver. I checked the parameters for the G401, which is a new driver, didn't really know about it before but it's so close to the original G400 that I don't think there's much difference. Even the parameters vary by just a few percent. The N401 however is better driver for horns as it's parameters are better for the use + it weighs less. I believe someone already uses the N401 in WSX iirc.
Like Glenn already said, the kick and speed of the sound is much more important than the LF extension in music. We built for our university's music club a simple bass reflex bins with a ~155L net volume and fb ~40Hz, simple and very effective for a small size with loads of kick. This type of design is still the most practical one in end of the day. If you look at the G-Sub plans, it has a higher tuning when using P300s compared PD186s, which is a very close approximation of what I just described above.
If you need to have a VLF design in a reflex bin, then you need a really long excursion drives with big voice coils like V18-1200, PD186, B&C18SW115 with big enclosures and low tuning but then you loose the upper bass range and need a separate kick bin to get any decent sound out of the system.
One thing quite interesting that RCF now have 2 identical drivers with different names. What's the point? Is just that they haven't updated the web site or are they really identical? Check the P400 and G400 on their new site.
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Nicholas_Hopsy
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Posted: 04 July 2015 at 8:10pm |
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What Enclosure would the L15P400 RCF work great in? HELP@!!!!!!!!!!
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Darkstar
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Posted: 04 July 2015 at 8:38pm |
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I have two horn 2x18" loaded with G401's and I can say they sound awesome and go "stupidly" low.
However there has been a thread here about some guy who built these reflex subs which are also loaded with G401's, thought you might be interested so here's the link: http://hornplans.free.fr/mtl-46.pdf Edited by Darkstar - 04 July 2015 at 8:39pm |
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Bass =/= Enough
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Calitri wrote: