2ohms Vs 4ohms & SQ

[Rattlebrain 10+ year member]

I had a set up one time useing an Autotek 7100 BTS on 2 12" Crunch subs.

I cant remeber all the specs on the amp or the subs but I do know that the amp was stable to at least 2 ohms and I think it may have been stable to 1.

Here is the question:

First set up I had with these subs, they were both 4ohm wired mono to a 2ohm load. They didnt sound good at all. I was expecting more power = better performance. Not the case here. I know the subs could handle the power.

Second set up I changed the 4ohm subs out to 8ohm subs and wired them to 4ohms. Same box, same type of sub. Sounded much much better.

Why?

I hear everyone talking about running thier stuff at 1 or 2 ohms all the time.

I just never understood why and since then I have only ran 4 ohms. I was just wondering if I was doing something wrong (i dont think I was) or what the deal is.

Click to read more...

 

[kustyn727 10+ year member]

you could of wired them wrong. Are the subs single or dual ohms?

 

[Rattlebrain 10+ year member]

No. I know they were not wired wrong. No douts.

They were single voice coil, 4 ohms, wired in parallel for a 2ohm load.

 

[Raven 10+ year member]

I did the same thing with my old SPL ELF subs. I can only guess some subs / amps are happy at high impedances.

 

[Rattlebrain 10+ year member]

bump

 

[jsloan10 10+ year member]

The amount of clipping would have been greater at 2ohms then at 4ohms which could have caused the diff in SQ, some lower level amps will handle the lower ohms but will have high THD at the lower load. Ive also seen situations where the sub sounded better with less power, I believe thats due to power compression in the voice coil.

 

[Rattlebrain 10+ year member]

This was back in early 90's I replaced a pair of RF punch for the Crunch. The crunch sounded better than the RF (after the switching 4 for 8 Ohms) Autotek now is crap, but at the time, it was considered a very good amp, with low distortion. Made in USA at the time. Oh well. Times change and so does technology. Thanks for the replys!!

 

[Decipha 10+ year member]

i have an autotek 400 thats 2 ohm stable

i don't know if it was a good amp back in the day but now its a POS

 

[JimJ 5,000+ posts]

Damping factor will always be a much greater indicator of sound quality than impedance alone.

 

[Jayhawkk 10+ year member]

Jack Frost, doesn't the damping factor change as you lower the impedance or is that another wives tale? I remember hearing years ago that as you lower the impedance the ability of the amp to control the woofer lowers(simplistic meaning I suppose) it's been a long time so maybe i'm distorting what I remember as well.

 

[bigwheel15 10+ year member]

i have an autotek 400 thats 2 ohm stable
i don't know if it was a good amp back in the day but now its a POS

Uuh, sorry to say it but thats not autotek, thats audiotek. That would explain it being a "pos".

 

[JimJ 5,000+ posts]

http://www.classic-audio.com/marantz/mdampingfactor.html

Read. Learn. Comprehend //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

The DF is the speaker's impedance divided by the amp's output impedance. So yes, a lower impedance speaker will technically have a lower DF, and therefore less cone control, than a higher impedance load. It's mathematically true, hardly an "old wives tale" //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

And yes - DF does affect the sound.

 

[JimJ 5,000+ posts]

This is not to, however, say that low DF systems are necessarily bad - the system in my sig is a perfect example of that, and I'd be surprised if it had a DF over 20 //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Jayhawkk 10+ year member]

Well, I added the wives tale comment to show I wasn't stating it as a fact since I wasn't sure //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif Looky there I knew something and didn't even know it . thanks for the link though.

 

[klassic 10+ year member]

there's often less dynamic headroom running lower impedence which would alone effect sound quality when pushed hard. Who knows what kind of other stressors (current demand, heat, current limiting circuits ect) effecting an amplifiers internals and performance at lower impedences. Some amps just tolerate low impedences better than others. those designed to tolerate low impedences usually sound just fine. I run my PG titanium at 2 ohms bridged and it sounds great and controlled. Cant tell any difference from 4ohms bridged. I've done the same with other amps (not intended to run at 2ohm bridged loads) and the difference in SQ from running 4ohms was quite obvious. at 4ohms bridged/2ohm stereo most amps should still sound fine. After that there are amps that get noticeably sloppy.