Nah the roof coating stuff sucks, i've used it before (in my cars, not on the inside of a speaker cabinet). its not butyl based and is no where near as effective (we're talking about stoping the sheet metal from resonating, which i assume is the point of using it on the inside of the speaker cabinet) ! It stinks, peels off in high heat, and is overall not on par with the second skin stuff. I mean in the grand scheme of things, an extra $60 for a gallon (which should be more than enough to do the inside of the box) isn't terrible.
Apart from Cone material, are there any other differences between the 18NLW9600 and 18NLW9600C drivers?
I am also wondering if the 18LW2400 compares favourably in terms of price vs performance compared to its higher powered N-Dym cousins?
Driven to its max, would there be a significant SPL difference, for 4 of Martin's cabs when loaded with 9600 vs 2400?
Sorry too many questions because I am thinking of dumping 12 Nos. of 3015LF drivers that are doing duty in my ported dual 15 cabs. Thanks for any inputs.
I am also wondering if the 18LW2400 compares favourably in terms of price vs performance compared to its higher powered N-Dym cousins?
Driven to its max, would there be a significant SPL difference, for 4 of Martin's cabs when loaded with 9600 vs 2400?
Sorry too many questions because I am thinking of dumping 12 Nos. of 3015LF drivers that are doing duty in my ported dual 15 cabs. Thanks for any inputs.
I have no first hand experience, but I think that if you drove each to their MAX, then the 9600's would totally destroy the 2400's, mainly because you can run them with say 4000rms each as opposed to 2500-3000rms each for the 2400's. But then you'd need double the amp power, double the cost etc. So it's not just the difference between the $330 or $700 driver, but also the amps to go along with each one. So figure a bridged xti 4000 or 6000 is about $650 (for the 4000) or $1500 each, and you would have to pair each of those with each box. So we are talking a 2400 in the cabinet with an xti 4000...total cost $1k. Then a 9600 with an xti 4000 or 6000 could be $1350-2200 each. Big difference in price there!
Also if you were very concerned about transporting this system, then maybe the two 9600 loaded cabinets and two 6000 amps would be the best option...
Also if you were very concerned about transporting this system, then maybe the two 9600 loaded cabinets and two 6000 amps would be the best option...
A 120V 20A NEMA plug on a 20A thermal breaker will pass 40A for one hour before tripping, 4.8KW.
An externally hosted image should be here but it was not working when we last tested it.
Live music usually has a break for the band every hour.
If you're doing playback only then you probably need to observe the 20A long term limit.
I use a distro with 4 20A magnetic breakers for the PA, and 8 for the lights (real PARs, not LED).
Consult the amplifier data sheet to see what actual power requirements will be on music. A Crown MA5002vz will draw 2156W on music into a stereo 2Ω load, which means it should be the only thing on a 20A circuit.
http://www.crownaudio.com/pdf/amps/131510.pdf
I use the Crest CA9 which is only about half the power at 4Ω that the Crown is. The CA9 is rated to draw 8.6A with pink noise at 500W (peak) per channel at 4Ω. Two of these will run on a single 20A breaker (if need be, I actually run one amp per breaker).
If you're doing playback only then you probably need to observe the 20A long term limit.
I use a distro with 4 20A magnetic breakers for the PA, and 8 for the lights (real PARs, not LED).
Consult the amplifier data sheet to see what actual power requirements will be on music. A Crown MA5002vz will draw 2156W on music into a stereo 2Ω load, which means it should be the only thing on a 20A circuit.
http://www.crownaudio.com/pdf/amps/131510.pdf
I use the Crest CA9 which is only about half the power at 4Ω that the Crown is. The CA9 is rated to draw 8.6A with pink noise at 500W (peak) per channel at 4Ω. Two of these will run on a single 20A breaker (if need be, I actually run one amp per breaker).
Last edited:
The Crest spec you refer to is at 1/8th power, 225 watts average (1800/8=225), which is more power than the amp would draw using pink noise as a source. I have used 4 CA-9 and 2 CA-6, with the clip lights just flickering, all on one 20 amp circuit. Found out they were all on one circuit when a mis-wired guitar amp took down the breaker instantly when plugged in..
The Crown MA5002vz power draw specs are a confusing bit of information.
They say pink noise has a "duty cycle" of 50%, "rock & roll" 30%.
Pink noise has 12 dB dynamic range, which is more than the range of some compressed music.
"50% duty cycle" power draw at 2 ohm stereo for the MA5002vz is 42.6 amps at 120 volts, "30%" draws 26 amps.
That said, music with 10 dB range only averages 500 watts when hitting 5000 watt peaks.
The type of music played, and the amount of compression or clipping can make a huge difference in the average power used.
They have almost similar overall max SPL’s when both used to their max power input. The 18 Sound pushes out about 1dB more then the RCF (in a 36Hz TH) throughout the bandpass except for < 45Hz. Under the 45Hz the RCF seems to have a little more output.
From an engineering point of view I would favour the 18Sound because it stays cooler (less power compression) under max load. If you compare motor to mass ratio they are very similar. Both use double spider suspension and only the 18Sound uses a double shortening ring system.
Soundwise most of my colleagues (me included) preferred the sound of the RCF but that’s personal. The RCF had a little less definition in the upper area but clearly sounded fuller in the lowest octave of the bandpass at max power. However the 18 Sound did sound less 'forced' at maximum power. But of course sound description is suggestive and very personal, I think.
I wish it was that simple Crescendo... Just compare the motor/moving mass ratio against the excursion and HornResp doesn't show the costs in THD and pwr compression...
BMS 18N850 V2:
AES = 1200 W
Xmax = 12 mm
BL = 25,4 Tm
Mms = 240 gram
18Sound 18LW2400:
AES = 1200 W
Xmax = 9,5 mm
BL = 25,6 Tm
Mms = 192 gram
RCF LF18N451:
AES = 1500 W
Xmax = 8,8 mm
BL = 30,2 Tm
Mms = 235 gram
You can see the extreme Xmax of the BMS that looks very tempting. But you also you can see it uses a similar motor compared to the 18Sound to move a cone that is even more heavy then the RCF cone! I'll bet that will result in more pwr compression...
So to me that means 80$ more for the BMS and plenty more to amplify the extra losses to get it at Xmax (if it doesn't burn before you get there...). Again, I repeat my statement that people look way to much to the Xmax and forget about the rest...
BMS 18N850 V2:
AES = 1200 W
Xmax = 12 mm
BL = 25,4 Tm
Mms = 240 gram
18Sound 18LW2400:
AES = 1200 W
Xmax = 9,5 mm
BL = 25,6 Tm
Mms = 192 gram
RCF LF18N451:
AES = 1500 W
Xmax = 8,8 mm
BL = 30,2 Tm
Mms = 235 gram
You can see the extreme Xmax of the BMS that looks very tempting. But you also you can see it uses a similar motor compared to the 18Sound to move a cone that is even more heavy then the RCF cone! I'll bet that will result in more pwr compression...
So to me that means 80$ more for the BMS and plenty more to amplify the extra losses to get it at Xmax (if it doesn't burn before you get there...). Again, I repeat my statement that people look way to much to the Xmax and forget about the rest...
That is 1600 watt at 1% THD. Not really rms, well the way rms is used usually.
Valuable info right here, folks.
Djim, I was just using xmax as a benchmark, keeping other variables in mind. (i.e. IF I can get 'x' driver to reach xmax, spl will be 'xxx dB', etc). If there is a better way to directly compare drivers in a given enclosure (short of mounting and testing), please let me know. I would like to stay as accurate as possible.
In theory you are correct but I think the power supply in the Crown isn't able to deliver more then 1600.
So, if the Re of the drivers get much lower then 4Ohm your THD will rise rapidly and you wont even get 1600 without clipping... My wild guess is that you will be able to get something like 1300 watts continue and about 2500 watt total with 1% THD with that load which is not bad at all from one amp at that price.