I have decided to go with 2 Polk 10" SR104's powered off a JL 1000/1

I may have gotten this a little mixed up but do I correctly assume that since the 1000/1 can put out full power at 4 ohms that it it better for SQ purposes to run a 4 ohm total sub load as opposed to a 2 ohm?

my options are

2 ohm load: 2 X SR104 SVC run in parallel

4 ohm load: 2 X SR104 DVC - running in parallel but running series across the voice coils i.e. running each sub at 8 ohms

Not even considering the other way to run 2 X (4ohm + 4ohm) subs at 4 ohms, that's a LOT of messy wiring.

Would the 4 ohm setup be better/the same/worse for sq? I should get a clean kilowatt either way if JL audio is not downright lying. The other thing to note is that I can get the DVC versions about $50 cheaper...

Generally its better to have too much power on tap, rathar than not enough.
To aquire good SQ its a combination of good equipment, decent installation and turning.

Im sure somebody will elaborate futher.

The power on tap is (according to JL) the same whether i have a 2 ohm or 4 ohm system.

correct, the 1000/1 uses a regulated power supply. so it can output the same power at 4/2/1ohms

you will not really HEAR any difference between running at 1ohm compared to 4ohms. so just go with whatever you want.
personally, i'd go with a 4ohm total load, just for irrational peace of mind

I would go with 4 ohm to prevent (sorry, limit) power compression.

THAT was the info I was fishing for. Thanks! The matter is now closed

now br85 has got an answe i thought id crash the thread..............but Ive always wondered what happens when you run an amp with a regulated power supply at say 8 ohms? is it just like a normal amp and power roughly decreases by half or??
Any light to be shed on this one guys and gals?

Well it seems from my JL slash amp manuals as if that would be the case. The amps would be fine and dandy powering an 8 ohm sub load at their maximum of 4 ohms, but the effective power would be halved, and I should think the sub voice coils might get a little bit hot. In the guitar realm I have run 16ohm speaker loads (yeah, 8 X 12 inch celestion vintage 30 drivers off a mesa boogie mark IV, MAGIC) off an 8 ohm setting on the amp, runs quieter, but still fine.

Better just to match things for peace of mind, if nothing else, imo. If you want to power something in your car that's 8 ohms, just buy another copy of what you're trying to power, and run parallel. hey presto.

No, in fact, running your amp at a higher nominal impedance is better for both the sub, and the amp (that is, if the gains are set correctly, and you are not clipping the signal to get more output).

The JL "slash" series amps are rated to put out the same power anywhere between 1.5 and 4ohms.

I did see a test of the 1000/1 years ago when it came out and it showed that even though it did infact produce more than 1000wrms at the different loads it produced significantly more at 4ohms. From memory it was a little bit over 1600wrms @ 4ohms compared to about 1400wrms @ 2ohms.

Wasnt it like 1450 at 1 ohm or something? i heard it was putting out a little over that, so we set up 4 boxed CVR's togethor running at 1ohm off the 1000/1.

RIPS uses 4 different voltage rails...well 3 plus a low impedence turn off stage.

This system is to protect the amp and keep all the components in spec. Its not really a benefit for the end user as far as power is concerned only reliability. 4ohms will be your most powerful setup (for the class d range 500/1 and 1000/1) with the largest voltage rail being inplace. As you demand more current from the amp due to lower impedences the amp will switch and stay switched to that lower voltage rail. From what ive heard you can disconnect the amp from its power supply for a period of time and then the amp resets to the highest voltage rail again.

its a very clever system that is marketed brilliantly. JLaudio gives you less power and headroom but reduces failures due to amp abuse. RIPS benefits JLaudio but makes the end user happy about having less headroom. They give the end user less potential power and make them happy about it.

Even though the RIPS system and the tightly regulated power supply gives you a lot less headroom and potential power i still love the JLaudio amps. Build quality is just amazing.

They may well have "less headroom", but if people are getting 1600 WRMS and 1400 WRMS at 1-4 ohms using drawn out test tones, surely this amount of power would mean that even with the RIPS system "giving a lot less headroom and potential power" - 1400 to 1600 is still much higher than what they advertise, so in reality, with these figures factored in, you should still get the same as, if not slightly more potential power and headroom than every other 1KW monoblock, shouldn't you?

yes i do love the jlaudio slash series amps. They are among the best fit and finished amps on the market. I do love the RIPS design i think its very clever and has been marketed in even a better way. Who would have thought that the customer would be happy about receiving similar power ouput into 4 - 1.5ohms!!

both the 500/1 and the 1000/1 amps are optimised for maximum output into 4ohms. As your current demands increase (due to either a lower impendence driver or higher input signal) then the amp goes into its first stage of protection, which is to decrease its voltage rails (which will be something like a 2ohm voltage rail). The amp does this once more if current demand reaches another set level and reduces the voltage rail again (1.5ohm rail). Then finally if current demand reaches another set level the amp turns off. 3 set protection stages to ensure that the end user doesnt abuse a amp designed for maximum output into a 4ohm load. Maximum power output is basically always known so the amp can be kept within its design limits.

RIPS is a very clever system coupled with the right thermal protection dramatically increases the reliability of this amp in the hands of some abusive users.

Due to the rips design there is really no need to use the amp with anything below a 4ohm nominal impedence. Loading down the amp will not increase power output dramatically, only increase distortion and reduce dampening factor.

1000/1 is a great amp worth buying and is under-rated. Basically its a 1300watt rms amp 4 ohm optimised marketed as 1000watts rms....so at least you get a little more than published.

If you believe in dynamic head room then this is definitely not the amp for you.

Ok the subs and the amp have now been shipped, will get here next monday. Quick question, though I doubt anyone will know the answer: What size sealed box do I need for ideal running of this sub? (net size, not including the .22 cubic feet that the basket takes up) I am going to have 2 entirely separate boxes, I just need to know the size of one. Some places say .66 cubic feet, some say .88 cubic feet, even the polk website and white paper has both listed in different areas. At first it just looked like they meant .66 for the 10" and .88 for the 12", but in other polk sources it says .88 and 1 for the 10" and 12" respectively. These are ALL listed as net volume enclosures. GAH!!

I would go about 0.7 for the 10", maybe 0.8 cu.ft. sealed.

1 to 1.2 cu.ft (sealed) is in the realm of 12" woofers.

ported is a whole other can of worms, with up to 3 cu.ft or more for a 10".