What do you know about a 100% DD setup?

[audioholic 5,000+ posts]

Huh? Nothing I wrote has anything to do with fuse ratings, just random impedance readings I took with my DMM and some fuses (and wires, etc.) I was juxtaposing the fact that fuses are supposed to act without resistance... to an amp likewise being ran near the point of zero resistance. There's a reason nearly every amp company only advertises power output down to 1 ohm, and no less.

A lot of fuses measure ~ .3 ohms. So, 2 ohms is obviously further from being a giant fuse than 1 ohm, no matter the topology, IMO.

Id had a few beers by the time of my last reply, which is probably why I didnt explain myself well. lol

Everything you wrote has to do with fuse ratings. Why you are bringing up fuse ratings, when the topic was different amplifier topologies react differently at a given impedance (so you cant generalize any specific impedance as sound bad), I have no idea. Nor do I know what "So, 2 ohms is obviously further from being a giant fuse than 1 ohm" means.

SoundStream use to advertise their "high current" amps rated power below 1ohm. Not really sure what that proves, however.

 

[audioholic 5,000+ posts]

You go to term pro and see how many burp cars go off of t/s, I'll save you the trouble none. Pretty much it is an educated guess to start off with. I can deff tell your old school by the way you talk.

You go to termpro and see how many SPL guys say t/s specs played no role in their choice of subs or design of their system. You keep implying that Im saying t/s and the end-all answer to building an SPL setup, when Ive said something very different.

I dont know what me being 'oldschool' has to do with anything here.

 

[schackel 10+ year member]

You don't have a dd batts, wire, box, alt, head unit, or deadener. FAIL

x2

 

[audioholic 5,000+ posts]

The difference is, it doesn't take near as many watts to get loud on an 8ohm system as it does a .25 ohm system. That is how you have less strain.

You have me scratching my head at this comment. 1000 watts @ 8ohms will make a stereo louder than 1000 watts @ 1ohm? No, it wont.

Also, the impedance question on it placing more strain on a charging system. Using: Amperage= √ (watts/ohms), you find that lower impedance does require more amperes; therefore, requiring more of an electrical system.

Amps pulled = watts created / volts. This holds true no matter what impedance the amplifier is running at. The only difference would be how the speaker impedance affects the amplifier's efficiency, which is also a function of the amplifier topology.

As far as killing a speaker faster, it is obvious if it is fed below the impedance of the coils. If it is not below the impedance, I can't accurately describe why that would kill a woofer faster other than the general amperage data calculated by the formula I just used.

What do you mean "fed below the impedance of the coils"? The coils dictate the impedance, so how would one go about 'feeding them below the impedance of the coils'?

 

[audioholic 5,000+ posts]

I would say nearer to a dead short would be classified as nearest to 0 resistance, which would be the class D at 1ohm. The A/B at 2ohm would be nearer to the amplifier failing causing an open circuit due to it being wired below it's nominal resistance, but the D at 1ohm would be nearest a true electrical short circuit.

You are correct that 1ohm is closer to a dead short than is 2ohms. But the point is there is no guarantee that the amp running at 1ohm will have higher THD, or lower damping, than a different amp/topology running at 2ohms.

 

[audioholic 5,000+ posts]

Low impedance = more of the electrical energy being converted into thermal energy rather than acoustic energy. Cooler, happier amps > hot, near dead short amps, IMO.

If we were only discussing one single amplifier, then yes you are correct. Lowering the impedance on that amplifier will make it run hotter, and lower its efficiency. But we are discussing the differences in difference amplifier topologies.

 

[brodeisel 10+ year member]

cant see page 13 hope this works

 

[Danometal 10+ year member]

Id had a few beers by the time of my last reply, which is probably why I didnt explain myself well. lol
Everything you wrote has to do with fuse ratings. Why you are bringing up fuse ratings, when the topic was different amplifier topologies react differently at a given impedance (so you cant generalize any specific impedance as sound bad), I have no idea. Nor do I know what "So, 2 ohms is obviously further from being a giant fuse than 1 ohm" means.

SoundStream use to advertise their "high current" amps rated power below 1ohm. Not really sure what that proves, however.

Nothing I wrote was even marginally relevant to fuse ratings. How can you say I am "bringing up fuse ratings?" I was speaking of the typical resistance of a fuse, as measured by my DMM. Say, arbitrarily, ANYONE ANYWHERE mentioned a fuse's rating of 100 amps. What's that got to do with my mention of any fuse's .3 ohms impedance?

And, the topic to my understanding was NOT amplifier topologies, but 4 ohms vs. 1 ohm vs. .25 ohms vs. 0 ohms, as is congruent with the colloquialism of "near a dead short."

And, if an amp was ran at zero ohms, it would be like a proverbial "giant fuse." Touching the pos & neg speaker wires together = dead short. Running said amp at .25 ohms isn't far from that. I hope that was clearer than my previous attempts to make this point.

 

[Danometal 10+ year member]

If we were only discussing one single amplifier, then yes you are correct. Lowering the impedance on that amplifier will make it run hotter, and lower its efficiency. But we are discussing the differences in difference amplifier topologies.

I wasn't aware you believed the primary subject (of this overlong thread about Digital Designs turned impedance debate) was amp topologies, like A/B vs. D, and all the due impedance implications thereof. I thought it was about "any ohms is less of a dead short than zero ohms," no matter the fact that most class A/B amps are less efficient at 4 ohms than a class D is at 1 ohm.

 

[audioholic 5,000+ posts]

Nothing I wrote was even marginally relevant to fuse ratings.

Not sure why you want to keep debating this, when Ive already quoted where you were discussing fuse ratings. Here, I'll quote it again...

So, 2 ohms is obviously further from being a giant fuse than 1 ohm, no matter the topology, IMO.

Yes, I realize your point relied on the resistance of the fuses, and I thought I adequately explained why my first reply wasn't more clear. But I find it odd you keep saying nothing you wrote is "even marginally relevant to fuse ratings" when it actually was. Lets put this "I didnt mention fuse ratings' argument to rest, because its not even relevant to the tangent-topic we have been discussing here lately.

Nothing I wrote was even marginally relevant to fuse ratings. How can you say I am "bringing up fuse ratings?" I was speaking of the typical resistance of a fuse, as measured by my DMM. Say, arbitrarily, ANYONE ANYWHERE mentioned a fuse's rating of 100 amps. What's that got to do with my mention of any fuse's .3 ohms impedance?
And, the topic to my understanding was NOT amplifier topologies, but 4 ohms vs. 1 ohm vs. .25 ohms vs. 0 ohms, as is congruent with the colloquialism of "near a dead short."

And, if an amp was ran at zero ohms, it would be like a proverbial "giant fuse." Touching the pos & neg speaker wires together = dead short. Running said amp at .25 ohms isn't far from that. I hope that was clearer than my previous attempts to make this point.

I wasn't aware you believed the primary subject (of this overlong thread about Digital Designs turned impedance debate) was amp topologies, like A/B vs. D, and all the due impedance implications thereof. I thought it was about "any ohms is less of a dead short than zero ohms," no matter the fact that most class A/B amps are less efficient at 4 ohms than a class D is at 1 ohm.

I have no idea why you weren't aware of my point on amplifier topologies, Ive mentioned it several times in this thread. Here, let me quote one of them to show you...

So is the difference in the 'quality' or the impedance? Again, topology and/or design plays no role, right? .5ohm always sounds bad?
Generalizations have gained a bad reputation for good reason.

So now we have established that I HAVE been discussing amplifier topologies. Again my point all along is people make generalizations about impedances without acknowledging that different topologies are designed to work optimally at different impedances. If we were only discussing one amplifier, sure we could make the blanket statement that 1ohm will be 'dirtier' than 4ohms. But we cannot make that statement about all amplifiers in all situations. Someone earlier in the thread (forget who) said they would never run a SQ sub below 4ohms, I find that to be a misleading statement at best.

 

[dbeez 5,000+ posts]

Audioholic could you move all this none topic related stuff to amplifier discussion instead of the ops thread this is pretty ****** to cloud it up with all this.

 

[hispls 5,000+ posts]

Can't we just get back to raining on OP's "I love DD" parade? I'm still waiting to hear where DD puts all their extra heatsinks and what precisely their amps do that every other Korean mid-fi doesn't? Also waiting to find out when they invented the large motor (can't be eary 90's since in 96, CV stroker and RF Power were the first scratching at the 160 mark and as I recall both were really way bigger than anything else at the time).

 

[audioholic 5,000+ posts]

Audioholic could you move all this none topic related stuff to amplifier discussion instead of the ops thread this is pretty ****** to cloud it up with all this.

I tried, early on, to ask people to stay on-topic. Very few people listened, and to be frank, this thread has been a train wreck from the get-go. But the OP hasn't seemed to mind the off-topic discussions, so I haven't deleted them (not to mention, it would basically mean deleting the entire thread lol). But yes, you are correct, I can/should/will at least stop contributing to the off-topic replies myself. And, if the OP requests, I'll be glad to delete all the off-topic replies, or the entire thread. IMO, its up to the OP, since its his thread.

It probably would be best to delete it, since even the replies about the OP's system (the thread's topic) are mostly negative, borderline insulting, and generally not respectful to him. He built a DD system, is proud of it, and wanted to show us. This should not mean he is responsible for answering questions regarding DD's manufacturing techniques, their approach to marketing their products, or where their amplifiers are made. So again, if the OP wants, Id be glad to delete this train wreck.

 

[hispls 5,000+ posts]

This should not mean he is responsible for answering questions regarding DD's manufacturing techniques, their approach to marketing their products, or where their amplifiers are made. So again, if the OP wants, Id be glad to delete this train wreck.

IMO if you want to make absurd assertations about "higher standards", "more heatsinks", "only stuff with American made parts" etc. and claims of one battery supplying power for 3 minute 12KW demos prepare to back up your claims. I suspect if the thread were titled "My new build DD subs and amps" and it started off a little different it wouldn't have degenerated nearly as badly nor as quickly.

 

[Danometal 10+ year member]

Not sure why you want to keep debating this, when Ive already quoted where you were discussing fuse ratings. Here, I'll quote it again...QUOTE]

Wow. Really? I'll provide anecdotal emphasis on my own statement:

///So, 2 ohms (further from a dead short than any lower impedance) is obviously further from being a (dead short, thus giant fuse (my chosen hyperbole), much like a dead amp is like a giant paperweight) than 1 ohm (closer to a dead short than any higher impedance), no matter the topology (I'm not focusing on efficiency, noise, how low of an impedance harms an A/B vs. D, etc., JUST the electrical resistance implications), IMO.///

And, I have always recognized that YOU were discussing different amp topologies, and I made no point in any regard to that (other than the fact that such things are irrelevant to my point), so it was just YOU discussing that, thus it not being THE discussion at hand. I was only trying to make the simplest of statements; any impedance greater than zero ohms is less of a dead short than zero ohms, thus it not being the best of ideas to run an amp at extremely low impedances, and you take each of my mentions of that as somehow being related to fuse ratings.

So, I give up. You win. Peace.