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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Subwoofer Forum => Topic started by: Steve Mason on March 06, 2018, 10:43:45 pm

Title: Proper wattage amp for subs
Post by: Steve Mason on March 06, 2018, 10:43:45 pm
I am running a pair of passive Peavey PV 118 subs 400w @ 8ohms program,  I have currently been running them in parallel, using a bridged Crown XLS 1000 to power them 1000 @ 4 ohms bridged. I am looking to put a little more power to them and also get some headroom. Spec sheet says 800w peak @ 8 ohms. What kind of specs should I be looking for amp output wise. Looking to maximize $$/watt.  Also the speakers are staying so please no advice to upgrade to jbls or Q's or (insert manufacturer here) subs. Thanks in advance
Title: Re: Proper wattage amp for subs
Post by: Chris Grimshaw on March 07, 2018, 04:28:29 am
If you put much more power in there, you've got an even better chance of burning the drivers. More power just means more power compression when you're running past twice the continuous rating of the cabinets (presumed 200w). You've said you don't wanna hear it, but the thing to do here really is upgrading the cabinets.

If you want to continue, a Behringer NU3000 will do around 2000w bridged into 4ohm. One side of an NU6000 will do the same, or you could put one on each side of an NU6000 for around 1.2KW per box.

You've been warned, though, that more power will almost certainly let the magic smoke out.

Chris
Title: Re: Proper wattage amp for subs
Post by: Gordon Brinton on March 07, 2018, 01:14:43 pm
I am running a pair of passive Peavey PV 118 subs 400w @ 8ohms program,  I have currently been running them in parallel, using a bridged Crown XLS 1000 to power them 1000 @ 4 ohms bridged. I am looking to put a little more power to them and also get some headroom. Spec sheet says 800w peak @ 8 ohms. What kind of specs should I be looking for amp output wise. Looking to maximize $$/watt.  Also the speakers are staying so please no advice to upgrade to jbls or Q's or (insert manufacturer here) subs. Thanks in advance
It depends somewhat on what type of material you play through the speakers. For example, for live bands, recommended amp power should be equal to the speaker's Program rating, (not to be confused with Continuous or RMS ratings). Thus, 400 Watts to each speaker, (or 800 W to the pair,) is adequate. As already mentioned, going way higher than that only moves you into the danger zone.

It looks like your Crown is rated at 1100 W @ 4 Bridged, so I would leave well-enough alone. If you need more volume than that, then your entire system needs upgrading.
Title: Re: Proper wattage amp for subs
Post by: Paul G. OBrien on March 07, 2018, 06:41:15 pm
Get an amp capable of about 700-800w/ch at 8ohms and you will have a substantial upgrade.
Title: Re: Proper wattage amp for subs
Post by: Tim McCulloch on March 07, 2018, 07:53:04 pm
It depends somewhat on what type of material you play through the speakers. For example, for live bands, recommended amp power should be equal to the speaker's Program rating, (not to be confused with Continuous or RMS ratings). Thus, 400 Watts to each speaker, (or 800 W to the pair,) is adequate. As already mentioned, going way higher than that only moves you into the danger zone.

It looks like your Crown is rated at 1100 W @ 4 Bridged, so I would leave well-enough alone. If you need more volume than that, then your entire system needs upgrading.

If the OP has the discipline to not over drive his rig he might benefit from some amplifier electrical and thermal headroom; the question is how much thermal headroom do his speakers have left in his existing powering scheme.  If he's had any steady clipping and the speakers are still living, he might have some room for more *unclipped* voltage.  Whether or not that translates into something audible that he likes (or not) is tough to guess online.

I agree that he's likely about maxed out with his current subs.
Title: Re: Proper wattage amp for subs
Post by: Richard Turner on March 07, 2018, 09:50:55 pm
Its your money, but the subs as  they are right now in functioning condition are more valuable than they will be in about 100 hours time with burnt up voice coils and dead drivers if you decide more power is more better. (eg send them on their merry craigslist way now as working than later as roasted)

I'm not sure what model of 118 you have as peavy has sold many boxes with the 118 number as part of the model number but I'd guess ether an old series BW with a 250w rms coil or the newer pro18 driver with "400 watt program power handling" which means 200 watt RMS.

that amp is a good enough power source, its not great but its going to do the job on those speakers well enough for general use, canned music or small band with proper use of compression where needed.

Run what you got till you can afford what you need and plan to get more for your money on next  purchase.