Feeding a large ported RL-P15 1400 watts???

[Jerm357]

With a design of 8.5cf and a tune of 17hz what are your thoughts of giving an RL-P15 D2 1400w? I ask because I have been using an EP1500 with this design but only sending it 450w at 4 ohms. In winsid the graph looks a little scary reaching xmax at about 28hz, but I see others being recommend to go with this wattage instead of the 450w. So what are your thoughts on doing this and how dangerous is this?

[ThomasW]

1400 watts is more than double the rated Pmax

[Jerm357]

So you feel its a bad idea as I do? Do you think 450w is the better option for this amp/driver combo.

[chasw98]

I am feeding my RLp-15 D4 with 2 channels of an EP2500, 4 ohms per channel, approx. 1300 watts. But I use the power for headroom rather than ultimate SPL. I am very careful with it.

Chuck

[oxcartdriver]

YMMV, I fed a RLp-15 D4 with a crown K2 (one channel for one voice coil) at max volume for 3+ hours. If the coils were actually 4ohms this would have been 1600watts. I used the Rives test CD looped on 20,25,30hz uncompensated test tones. No issues. In the modeling software the coils were actually about 6ohms which would still equate to greater than the max power.

I noticed a significant reduction in stiffness of the cone surround after this break in. Your neighbors will not be happy with the noise or vibration though.

http://www.htguide.com/forum/showpost.php4?p=290585&postcount=3

[---k---]

YMMV, I fed a RLp-15 D4 with a crown K2 (one channel for one voice coil) at max volume for 3+ hours. If the coils were actually 4ohms this would have been 1600watts. I used the Rives test CD looped on 20,25,30hz uncompensated test tones. No issues.

I don't think that method of testing is generally recommened or safe for those not willing to risk the cost of a fried driver.

If one ould like to break the driver in, I think regular program material at moderate volume levels is best.

[oxcartdriver]

I don't think that method of testing is generally recommened or safe for those not willing to risk the cost of a fried driver.

Agreed. I was quite concerned about bumping the coil on the magnet assembly. Didn't happen however.

I run the crown K2 at -13dB and the Velodyne SMS-1 at level 15 out of 100 to match the output to my WWMT towers driven by a NYAL Moscode 300 amp.

Normal source material barely moves the driver cone with sane listening levels. It was abusive, but fun in a Tim Allen kind of way.

[Licinius]

Agreed. I was quite concerned about bumping the coil on the magnet assembly. Didn't happen however.

I'd have been much more concerned about melting something =) but glad you pulled it off :T :B

[oxcartdriver]

The duty cycle of the input was probably about 85%. The model predicted the voice coil was 6+ohms. If this is correct then these numbers could have derated the applied RMS power enough to allow the driver to survive.

[Jerm357]

The EP1500 doesent even realy put out 1400w in bridge mode when used to cover the 80hz - 20hz anyways right? Like in the manual is says for stereo mode the ep1500 puts out 450w @ 1 kHz 0.1% THD and 400w @ 20khz-20hz so it should be less than 1400w anyways right? Does anyone know what the wattage is for bridge mode at 20khz-20hz @ 1% THD is?

[WillyD]

The EP1500 doesent even realy put out 1400w in bridge mode when used to cover the 80hz - 20hz anyways right? Like in the manual is says for stereo mode the ep1500 puts out 450w @ 1 kHz 0.1% THD and 400w @ 20khz-20hz so it should be less than 1400w anyways right? Does anyone know what the wattage is for bridge mode at 20khz-20hz @ 0.1% THD is?

I'll post what someone sent me in a PM....

In the real world, amplifier output can be much less
than advertised playing 20hz at 1% THD with sagging power supply.

Don't be fooled, even the best electrical install has
sagging power.

My single PLX hooked up to 8 awg romex from
the main breaker to garage caused a 10VAC
drop in AC line voltage, from 120VAC down to 110VAC.

Seems miniscule, but the PLX at sine wave testing
was only able to produce 2000w bridged @ 4 ohms
vs. advertised 3400w.

Imagine what the cheaper amps do with AC line
sag.

From the binks test, if you look at the Crown K2,
800w/ch @ 4 ohms.

117 AC test;
Tested 724w @ 20hz

96 AC test;
Tested 446w @ 20hz

Imagine bridging the Crown into 8 ohms thinking
you'll get 1600w, but in reality you may only get
less than 900w.

The only amps immune are 'PFC' based proamps.
PFC allows full power even if you have AC line sags.

[oxcartdriver]

Line drops yet another factor to add to the mix. I did not measure the line voltage while completing driver break-in. I will have to measure line losses when I return from this business trip.

[Jerm357]

Heres the responce I got back form Behringer....

Q- "I know the power rating for the EP1500 1khz @1% THD is 1400watts at 4ohms but what is it for 20hz to 20khz? Would it be about 1000 watts to 1100 watts by any chance ( I hope so because that would be great for my design)"

A- "Thank you for writing, - that particular number is not a published specification (readily available), but your estimation seems to be in a reasonably safe range."