SQ @ 4 ohms verses 1 or 0.5 ohm?

[VWBobby 10+ year member]

Strange question.....

I remember reading somewhere that speakers were more(less?) efficient at higher ohm loads compared to lower. Example: Wiring a DVC 4 ohm sub at 8 ohms compared to 2.

This is strictly a SQ question not max power/SPL question.

Which will have better SQ, given the amp can drive both ohm loads?

I know ohm loads are very critical to amplifier efficiency, but I'm not sure if that has an effect on SQ?

Those in the know, please discuss....

Thank you in advance! //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

-Bobby

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[gunz4me2 10+ year member]

It depends. Amplifiers built to be both stable and deliver max power at .5 ohms are usually a totally different animal than one that will give you maximum power at 8 ohms.

First you have the high current versus high voltage argument and my opinion of high voltage 12 volt amplifiers may be a bit biased because I never ran one that worked out for me on a subwoofer with modern electronic music. Generally, an amp that gives you a boat load of power at 8 ohms will be high current and it is limited by the constraint of one's 12 volt electrical system trying to step up 12 volts DC to as much as 120 volts, or more, AC. Granted, there are some exceptions to this, but those are few and far between while being extremely HUGE (think US Amps surfboard here!). Just don't believe the hype when a certain nuthugger claims their bonerriffic old school amp can produce 1,500 watts RMS all day long on a 60 amp slow blow fuse at 8 ohms because it is high voltage. DEMAND a 30 second burp at max power while measuring the actual output power if anyone ever tells you this, and report back as to what happened.

Next, a low impedance amplifier capable of delivering max continuous power at .5 to 1 ohm will generally be of the high current variant. The old school of thought was that it was easier to make power by running an amplifier close to a theoretical short, but it was harder on the internal components within the amplifier. As long as you can feed it the supply current it needs, you should be golden for output. Now how long it will last is a toss up. My old Crossfire BMF1000d had a new board put in it in 2004, and has been going strong running at 1 ohm since then. It is currently rocking along in a friend's car! I still have several old school Orion HCCA 225s because I can't let go of the past, and let's just say I can come close to frying hot dogs on the heat sinks if I run them at 1 ohm.

Finally, you must define SQ when it comes to a subwoofer. Technically a "Sound Quality" sub setup would be one that properly blends with the rest of the system. As long as one is running an adequately designed amplifier for their given impedance with a properly implemented sub, the final impedance load shouldn't impact sound quality as much as one would think! After all, most subwoofers only reproduce a fraction of the audible musical spectrum and most individuals can't even hear distortion in the sub bass spectrum until it reaches double digit percentage levels (i.e. 10% or more).

 

[cleansoundzz 10+ year member]

Good post Chris.

 

[Why So Cereal? 5,000+ posts]

It depends. Amplifiers built to be both stable and deliver max power at .5 ohms are usually a totally different animal than one that will give you maximum power at 8 ohms.
First you have the high current versus high voltage argument and my opinion of high voltage 12 volt amplifiers may be a bit biased because I never ran one that worked out for me on a subwoofer with modern electronic music. Generally, an amp that gives you a boat load of power at 8 ohms will be high current and it is limited by the constraint of one's 12 volt electrical system trying to step up 12 volts DC to as much as 120 volts, or more, AC. Granted, there are some exceptions to this, but those are few and far between while being extremely HUGE (think US Amps surfboard here!). Just don't believe the hype when a certain nuthugger claims their bonerriffic old school amp can produce 1,500 watts RMS all day long on a 60 amp slow blow fuse at 8 ohms because it is high voltage. DEMAND a 30 second burp at max power while measuring the actual output power if anyone ever tells you this, and report back as to what happened.

Next, a low impedance amplifier capable of delivering max continuous power at .5 to 1 ohm will generally be of the high current variant. The old school of thought was that it was easier to make power by running an amplifier close to a theoretical short, but it was harder on the internal components within the amplifier. As long as you can feed it the supply current it needs, you should be golden for output. Now how long it will last is a toss up. My old Crossfire BMF1000d had a new board put in it in 2004, and has been going strong running at 1 ohm since then. It is currently rocking along in a friend's car! I still have several old school Orion HCCA 225s because I can't let go of the past, and let's just say I can come close to frying hot dogs on the heat sinks if I run them at 1 ohm.

Finally, you must define SQ when it comes to a subwoofer. Technically a "Sound Quality" sub setup would be one that properly blends with the rest of the system. As long as one is running an adequately designed amplifier for their given impedance with a properly implemented sub, the final impedance load shouldn't impact sound quality as much as one would think! After all, most subwoofers only reproduce a fraction of the audible musical spectrum and most individuals can't even hear distortion in the sub bass spectrum until it reaches double digit percentage levels (i.e. 10% or more).

GREAT post! Just to be sure, though, does this mean that a "high current" amp would be easier on your electrical (as in less voltage drops) or the other way around?

 

[Z1NONLY 10+ year member]

I thought damping factors suffered as impedance decreased?

 

[Danometal 10+ year member]

Wow. I was getting ready to type something up, but gunz4me2 was extremely on point. Well said, man.

...And, I believe "damping factor" doesn't hold but a fraction of the weight as the marketing machines lead you to believe. Nonetheless, my personal preference is a 2 ohm load for a sub(s) on a high efficiency monoblock. Subs don't need Class AB amps, but if you have the charging system to support their inefficient designs, a barely marginal improvement in SQ can't hurt anything.

 

[gunz4me2 10+ year member]

GREAT post! Just to be sure, though, does this mean that a "high current" amp would be easier on your electrical (as in less voltage drops) or the other way around?

Quite the opposite. It still takes a steady supply of current to step up that voltage and maintain it because one can not violate ohm's law no matter how you slice it. Remember, Volt x Amps = Watts and you are limited by the constraints of the 12 volt electrical system in a high voltage situation. My bias against high voltage 12 volt DC amplifiers amplifiers stems from the fact that many are NOT designed to reproduce long, drawn out, bass notes and will literally fall on their faces reproducing most modern day electronic music.

It is my opinion that high voltage amplifiers are best left to the home environment where one starts out with 110 to 120 volts AC.

 

[Why So Cereal? 5,000+ posts]

Quite the opposite. It still takes a steady supply of current to step up that voltage and maintain it because one can not violate ohm's law no matter how you slice it. Remember, Volt x Amps = Watts and you are limited by the constraints of the 12 volt electrical system in a high voltage situation. My bias against high voltage 12 volt DC amplifiers amplifiers stems from the fact that many are NOT designed to reproduce long, drawn out, bass notes and will literally fall on their faces reproducing most modern day electronic music.
It is my opinion that high voltage amplifiers are best left to the home environment where one starts out with 110 to 120 volts AC.

Makes sense, I was wondering about that ohms law thing but thought maybe I was missing something.

 

[VWBobby 10+ year member]

Chris, Thank you for the detailed response. It makes sense about the current demands at low ohm loads compared to high ohm (high voltage) loads. I have owned a few SoundStream amps that even have the high current/high voltage switch on the bottom. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Granted, subwoofer applications really wouldn't benefit from the marginal "perceived" SQ difference. Especially since most people are only reproducing 20-80hz with their subs. I guess I should've expanded the subject to ALL speakers.

Just for sake of discussion, lets say you have infinite current and voltage available (home theater).... Why do the home theater and pro audio speakers generally have 6-8 ohm impedance? Is it due to the nature of the amplifier (power supply) or does it have more to do with heat efficiency? Does the damping factor of a higher ohm load effect SQ in a broader range, say 100hz - 20khz? The reason I ask is I feel like there must be a reason the majority of speakers are 4-8 ohms instead of 1 ohm and wired in series......?

Knowledgeable one, please make it rain.... lol

 

[SQ is my deal]

Interesting topic. Comming from home high end audio I can tell you a couple things I've noticed.

Damping factor isn't just a marketing term like you might think. A typical reciever's damping factor is somewhere around 60. A high end monoblock amp (that I own and have in my store) has a damping factor of over 1200! From my understanding, damping factor is the ability of the amp to control the drivers motion. You can definately hear the difference. At home, current is almost always more important than watts.

Also, when bridging an amp you not only double the wattage, but you double the distortion. It would be better to have an amp designed for the wattage you need than to bridge amp channels to get that same power.

I know as ohms drop amplifier efficiency drops as well, which makes me think that a more efficient system would sound better due to more amplifier headroom and less distortion... I think that in real world situations that's probably not always the case. Therefore, I think that you can't make a generalized statement that lower ohms or higher ohms sound better, because it probably depends more on how a certain amp reacts to a certain speaker ect. That's just my 2 cents!

 

[VWBobby 10+ year member]

SQ is my Deal, that makes sense also. If you think of the speaker as a servo or linear motor (because that's what it is, really), then a more precise power supply (amplifier) would give a better reproduction of sound. If the amplifier is getting too much feedback voltage or inductance fed back into the amp, then the amp would have a hard time controlling the speaker.

I look at it similar to fuel injectors (hear me out, lol). Higher ohm rated injectors are easier to drive and generally modulate (control) better, less feedback into the ECU.

I guess this is how "damping factor" can directly relate to SQ, given that the amp isn't having to fight the speaker to get it to produce the exact waveform it is being sent. Does this make sense, or am I way off base? //content.invisioncic.com/y282845/emoticons/nerd.gif.c6fa51ddf7ff75f1c0371fbc648f70ae.gif

 

[SQ is my deal]

Yeah, that sounds about right.