kbonarek

Alright...hearing the kickdrum to any perfect circle song is great...but feeling it is better. So along that train of thinking, is it possible or would it be wise to attempt the following:

Strapping 2 amps (alpine pdx1.1000) to a single 12w7?

Alternately, doing the same to a 13w78 if it's a better idea.

The 12 is listed at 1000w optimal power handling and the 13 around 1500w, but the general concensus seems that these subs are power hungry. I just don't want to see any "magic smoke" coming from my gear after a week of use. I can't find any info on strapping the pdx amps and i havn't looked really hard to see if the w7's are svc or dvc subs. I'm assuming they're dvc, 6ohm each, 3 in parralell.

Someone help me out here....please :-)

jalat

iTrader: (6)

the alpine 1.1000 will do 1000rms at 4, 3, and 2 ohms so there is no need to strap another amp onto the 12W7. it would be a perfect match just how it is.

Green Hornet

Ok, here's the deal with what you are trying to do. The 12w7 is a single voice coil, so you can only use 1 pdx amp, you will get a solid 1000w out of it which is what that sub wants for continuous power. If you get the 13w7 you can use 2 pdx amps, 1 to each voice coil as it is a dual voice coil. There are 2 possible problems doing that, the voice coils 1.5 ohm, which may be too low for the pdx amps and they might be protecting on you, as well you will be getting over 2000 watts continuous which might end up blowing that woofer.

As I said, the pdx amps are not strappable, so you cannot put 2 on the 12w7.

BTW, why has the dealer you are talking to not told you all this????

kbonarek

Havn't been making a trip to the dealer everytime I have a question. It's easier to pick all the brains of the wise and almighty here on the forums :-) Thanks BTW, the answers are much appreciated.

I did go to the dealer to listen to the focals that I picked out though. The pdx amps are a little harder to come by to listen to here. The shop owner has a 12w7 in his car, but different car, different amp, different box = different sound.

The only reason I want to put more power to it is that my previous set-up was initially 2 Infinity prefect 12DVq's in a ~2cu.ft. ported box tuned to around 24hz as I recall. I then switched to a single Perfect in a 2 cu ft tuned to around 32 hz. Both were powered by a phoenix Xenon 1200.1. Similar power specs and so on. The sub is rated at around 400rms i think. Never killed it, so i just figured most subs could handle more than their rated power, seeing as the perfect aren't known for their power handling. Plus...the 2 12's sounded phenomenal but the space and weight weren't justifiable for me.

So i'd like to get the same level of intensity out the single JL. So maybe the 13w7 and 2 of the JL HD750/1 amps would be a better choice....brings me to around 1400wrms which is the rated nominal for the 13.

TragicMagic

I had to look up that Xenon amp. Impressive. Puts out all that power between 1 and 4 ohms. So the pair of 12DVQ's were splitting that 1200W for 600 each. It that single Perfect sub just one from the pair? If so, I'm surprised you were able to feed a 400WRMS subwoofer 1200W without having an issue. I'd agree that most quality subs will handle more than their RMS, but only within reason, and maybe for a shorther length of time...

If you still have that PG Xenon amp, why not use that one with the new JL sub? Then, spend that money you'd have for the new amp on a custom enclosure instead. I'd suggest getting the 13W7. You'd have 20% over the RMS from the Xenon. That'd be a good combination.

If you don't have that Xenon amp, then the Alpine amp and the 12" JL would work too. You'd still be over the RMS with this setup, but used with caution, I think you'd be alright.

kin0kin

You can connect a 100wRMS speaker to a 4000wRMS amp without problem. Current are only drawn as they are needed. Connecting a 400wrms sub to a 400wrms amp doesn't mean that your sub is drawing 400wrms. Similarly, connecting a 400wrms sub to a 1200wrms amp doesn't mean that the sub is drawing 1200wrms and that there will be a problem.

There will only be a problem if you mindlessly jack up the volume to the point where the sub is pulling more than 400w (what it's rated for) worth of power from the amp. The voice coil overheats and the sub just "blow" up.

If the concept of power is hard to comprehend, just think about this...how many "RMS" do you think your wallplug is rated? If your fuse was rated 10amp, @ 120v, it can handle 1200w of power draw. If you connect a 6amp vacuum cleaner to the wall, drawing 720w of power at peak, should you be worried that your vacuum would blow up?

TragicMagic

Current is only drawn as it is needed? The subwoofer doesn't dictate that. The signal from the HU unit does.
The sub doesn't draw the wattage. Its sent by the amplifier whether the sub can handle it or not. Based on the driver's impedance. By keeping all the gains, volumes, bass controls near minimum levels you can run a 400W subwoofer on a 1200W amplifier. Since you're purposely setting the amp up to do little with the incoming signal. But what's the point of having all that power available if you're not going to use it.
The wattage peaks when the music tells it too, if that makes sense. If you had a song with no bass, then the amp wouldn't get much of a signal from the Head-Unit to amplify, and therefore wouldn't put out much wattage. If you had a really bassy song, then the amp is going to be fed a 'large' signal from the HU, amplifies it, and generates a lot of power to send to the sub in order for it to duplicate the signal being sent by the HU. In both cases, the amplifier is always ready to send out 1200W. If the signal doesn't make it do so, it won't.

kbonarek

Ya, like Tragic was saying, the HU had 8v pre-outs, so the gain on the amps was set at the min. and the subs were never driven into distortion.

The reason for replacing the xenon(s) with the pdx series is footprint. The xenon is twice the size, so if i can cram 2 amps into the same spot, 2x the power :-) Savvy...

Spending the $$ on the enclosure isn`t really an issue...i`ve built more enclosures than I care to remember. So that`s why i was considering dropping the extra coin on the 13w7 and another amp...2000wrms is 500rms over, but like you said: if i don`t push it too hard, I should be alright. The w7 looks to be a pretty rock solid built sub too...

manethon

look into the re xxx. Also i wouldnt be to worried about feeding the w7 some power. With the impedance rise it will almost never see close to rated power. its distortion, shitty box and clippin your amp that will cook your sub, oh and playing 20 hz tones all day.

I had one hooked up to a rf t3000. Ran just fine! Tune low and set your gains conservatively.
I will never ever buy a w7 ever again! THere are way better choices out there for allot cheaper.

unholysavage

iTrader: (1)

wut?
LMAO!!