For those of you who haven't seen the other tread on 'ohms', Dalton and I had a disagreement. He is certain that a dual 2 ohm sub run in parallel (1 ohm) to a given amp will be no louder than the same sub run in series (4 ohm), all other things being equal, despite the fact that the amp will put out roughly 4 times the power into the 1 ohm load.

I said that it would be louder, in parallel, by 4-6 db.

To test this, we took the Critical mass 12 (dual 2 ohm) in my esclade, and hooked it up first in series (4 ohm) to my Sundown 3000 and then in parallel (1 ohm). Each time, we did a full volume pull, with a 45hz sine wave, and measured on my Termpro, recording max db.

In Series, we pulled a 140.1, and in parallel, we pulled a 143.8. These were back to back pulls, no other changes.

Like I said, I was wrong...it wasn't 4-6 db, it was only 3.7 On paper, it should have been 6, so it could be that I was reaching Xmax at that frequency, or it could be power compression, or some other variable. Point is that 3.7 db is both substantial and noticeable, Despite what Dalton preached as gospel in the other thread.

All this will be repeated at the meet next Saturday, provided Dalton still shows up with my $10.

As for PO57 saying that in the demo he heard sound quality suffered...that I haven't tested. Again, on paper, the dampening factor will be lower, and the amp will have less headroom, but I don't know what that will translate to on a very over motored sub like my CM and a beefy amp like my Sundown. At 1 ohm, it sounds better than just about any sub setup I have heard...could it sound better at 4 ohm...dunno. Perhaps we will do some soundquality A/B testing at the meet, as well.

On a slightly unrelated, but interesting note, I was setting the gains on the 3000 using a voltmeter. 3000 watts into one ohm (what the amp is rated at) works out to about 55 volts. Well, with no load on the amp, I was able to get over 90V, and that was with lots of gain left! I didn't have a scope, so its quite possible that the wave wasn't pretty. And, there is no saying that the supply has enough guts to carry that type of voltage with an actual load hooked up, but it is still quite substantial.

Toby

 

I stand corrected, although I am sure theres a formula to work out the actual loss to inefficiency.

Your $10 will be delivered on the 8th

 

Keep the $10. Better yet, buy an extra toy for a tot.

I'd be happy thinking that you just MIGHT think for an extra millisecond before posting things like this:

I feel bad for ppl who got this explanation - its totally wrong.

"resistance goes down, current goes up."

Lower ohms means less resistance yes, but NOT more power

As for the inefficiencies that lead to someting less than 6 db...I am sure there are formulae, as well, but have never seen anything concise. I'm sure its a combination of everything from resistance of wire going up as current increases, to coil flux, to cancellation due to something rattling at 143 that didn't at 141, to ??. Since even the best conventional loudspeakers only use about 1-2% of the power given them to make sound, there are probably lots of things to consider. When I get more time, I'd like to try the same test at different frequencies. As the frequencies get higher, the power to reach xmax goes up, and that might make for a bigger spread.

You have officially vacated ignorant, without reaching stupid...for this topic, at least

Toby

 

In regard to the 90volts... the Sundown 3000 has been tested to put out over 7000watts ... of course that is on a 17volt system lol.

 

well good for you.. im glad you werent totaly wrong.. but your right on it.. good job.. rep for you..later

 

good info for people who dont understand OHMs and such.

Just proves why my dual 2 ohms are louder wired up to 2ohms instead of 8 or 4. I wanna wire them down to 1/2 ohm but i need an amp to handle it, mine is only 1ohm stable.

I cant wait to get my truck measured... im only expecting in the 120`s but its louder then anything ive ever owned and can be heard a good block away so we will see.

 

why 1/2 ohm. just get a more powerfull 1 or 2 ohm amp

 

why try and maintain any type of clean sound? sloppy and loud =/


I still wanna see hardcore cleanliness results on a meter

 

I could just get a bigger 2ohm stable amp. i would like a 1/2 ohm because it should run cooler.

 

1/2 ohms will use MORE current hence MORE heat.