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What is the recommended power for this load

post #1 of 8
Thread Starter 
I have a sub driver rated 300W RMS and 4 ohm rated. Connecting 2 of it in parallel would make it a 2 ohm load with 600W total RMS.
The peak RMS for the driver is 1200W. What's the recommended power to drive this system such there there is sufficient headroom?
post #2 of 8
Thread Starter 

post #3 of 8
I'm not sure what you're asking, but if you're goal is to deliver 600 peak watts to each speaker, at a 4 ohm load, you'll need to deliver about 12 peak amps to the driver.
post #4 of 8
Thread Starter 
i am basically trying to understand what is the recommended power in watts i need from an amp to drive two of these connected in parallel. Combined load is 2 ohms not 4 ohms.
Should I drive with an amp that is rated 600W for 2 ohms (300W each driver, hence 600W total) ? or much more? If more, how much more is recommended?
Edited by ShaQBlogs - 10/4/12 at 8:06am
post #5 of 8
generally speaking, speaker power ratings are thermal ratings. That is, it's how much power they will take before the voice coil melts. Generally speaking, with woofers, most of what I read suggests that the device will cease to be linear (start compressing) and possibly start making ugly noises by somewhere around 1/2 of the thermal rating. AFAIK, peak ratings are essentially meaningless. I think they are often simply the instanteneous power at the top of a sine wave at the max RMS level, which means they're a different, less informative. way of saying the same thing.

How much power you need depends on how loudly you want to play (and the not little issues of box design, especially for subs). You need enough power to get them as loud as you want them. That's what a designer would recommend. The speakers do not NEED 300 watts each to make sound. In fact, in a normal room, if you aren't using a lot of EQ to boost extension, you can achieve very loud levels (certainly over 100 dB, with well under 50 watts. Depends on the sensitivity of the speaker (and whether that sensitivity rating is relevant at subwoofer frequencies or cops out by using a psuedo-industry standard 1 KHz tone . . . . Just because they theoretically can see 600 watts without immediately failing does not mean you ever will need to give them that much power. Those Infinities are 93 dB at 2 watts. So 2 of them at 4 watts (assuming they are co-located) would be about 98 dB. So 40 watts would yield 108 dB, and 80 watts about 111 dB and 160 watts about 114 dB. Movie reference for the LFE channel is 115 dB. So ignoring added burden from bass management, it takes something like 200 watts to hit 115 dB. Theoretically, anechoically. If you put the sub on the ground or on the floor, you gain 6 dB from dividing the space in half. If you put it on the floor against a wall, you gain another theoretical 6 dB 9but walls and non-concrete floors will have some loss . . .) Then there are losses as you get farther from the sub (6 dB per doubling of distance (from one meter) anechoically, very difficult to predict inside rooms where pressurization starts to control SPL rather than wave propogation at subwoofer frequencies).

The most important thing, probably, is to be sure your amp is rated to 2 ohms under the conditions you will use it. For example, lots of pro amps are rated to 2 ohms, and lots can be bridged to increase power, running them as mono amps. But in bridged mode, a 4 ohm load looks like a 2 ohm load to the amp, and a 2 ohm load looks like a 1 ohm load. If you push the amp hard with impedances below it's rating, you're likely to generate a lot of distortion, followed by icky smells and smoke as the amp dies.
post #6 of 8
Thread Starter 
I was basically looking to pair it with either Crown XLS 1500 or Crown XLS 2500. From your post, it looks like the crown 1500 would be more than sufficient for my needs, driving with just one channel.
post #7 of 8
I would connect the speakers in series and then run the amp bridged.Most amps at 2 ohms have a higher thd.
post #8 of 8
Thread Starter 
Originally Posted by Dezmond View Post

I would connect the speakers in series and then run the amp bridged.Most amps at 2 ohms have a higher thd.
I intend to connect another sub at second channel
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