Getting new R1200-1D Monoblock amp tomorrow, not sure how to safely pair ohms withsub

[The_Quiet_One 10+ year member]

Ok, I also said the OP should be fine setting it that way and it's all good with other people saying that it should be fine. My issue is people telling him to disregard fundamental physical concepts and not informing the OP of the limitations of setting it with a DMM. It shouldn't be rocket science, but if he understands possibly pitfalls he may lower his chance of blown equipment. On the off chance he blows his equipment will you refund him? I'm just making sure OP has the opportunity to understand electrical theory more fully and understand limitations of the DMM method. There is a phase angle even in RMS. RMS is calculated from peak alone on most dmms that people will have available. As far as HU volume that's up to OP. I would caution him to listen carefully to figure out the volume he uses to set his gain and make sure it isn't clipping or sounds distorted since no one specified why they chose 75% of max volume.

This reminds me why I post so little on this forum. I try and give a informative answer to a question and people get all up in arms because a more proper way is "rocket science"; I didn't even flat out try telling OP to not set it by DMM. I understand people don't have access to the proper tools and you can only set gains to the best of the tools available and your ability. Not everyone knows what clipping sounds like else I would say sub manufacturers would have a lot less issues with blown subs trying to be warrantied. What does a DMM measure? That could be a saw tooth, sine, or square wave form. What happens when an amplifier is starved for power? What happens to the signal wave? I'll let you research that on your own.

As far as OP I would use a mixture of your ears nose and the DMM to set your gains. use the DMM method to get you in ballpark If it starts sounding bad, bass isn't really getting louder/may get more quiet, or gets smelly time to lower gain or volume.

 

[fatboytyler]

What are you talking about? Do you not know there is a difference between AC and DC voltage calculations? There is a phase angle you have to take into consideration when dealing with AC signal (Speaker output of the amp is AC) The DC version of Ohm's law and the DMM method gets you in the ballpark, but isn't a great way to set your gains imo. It's better than just guessing, but leaves a lot to be desired. HU volume to set gains depends on HU and telling OP to trust the 75% mark to be distortion free could lead to trouble depending on the head unit. Also depending on his electrical the voltage reading may be reflecting a square wave. Everything else you suggested I agree with though and he shouldn't run into issues unless he plays tones or plays heavily bass boosted music. It's important for OP to know some of the possible pitfalls of using the DMM method and roll with those considerations in mind.
Op what's you head unit and electrical like?

Go read any guide to setting gain with a DMM and they all suggest 75% volume. Lots of head units, especially lower units, start to clip above that. And what the hell are you talking about with the voltage? Voltage is voltage. Regardless of triangle, sin, square etc. the peak voltage is within 1% of each other.

 

[The_Quiet_One 10+ year member]

Lol, that's like saying signal is signal. Why do you generally set the gain at 75% HU volume? All volume does is adjust the output voltage of the HU. Why does even the DMM method insert the caveat to not use full volume?

 

[n2audio 5,000+ posts]

And what the hell are you talking about with the voltage? Voltage is voltage. Regardless of triangle, sin, square etc. the peak voltage is within 1% of each other.

It's a peak vs rms issue.

DMM's measure rms.

Sine wave rms is .707 peak

Square wave rms = 1.0 peak

Triangle wave rms = .577 peak

Why this matters, I know not.

If your electrical system is so bad your amp is for some reason outputting a square wave you probably have bigger issues than how to set your gain accurately.

 

[fatboytyler]

Lol, that's like saying signal is signal. Why do you generally set the gain at 75% HU volume? All volume does is adjust the output voltage of the HU. Why does even the DMM method insert the caveat to not use full volume?

Lots of head units still clip if its outputting 100% voltage. I'm going by what 95% of people and guides say to do...

It's a peak vs rms issue.DMM's measure rms.

Sine wave rms is .707 peak

Square wave rms = 1.0 peak

Triangle wave rms = .577 peak

Why this matters, I know not.

If your electrical system is so bad your amp is for some reason outputting a square wave you probably have bigger issues than how to set your gain accurately.

Thanks for the clarification. I threw out that 1% number out of nowhere. It was based on distant prior knowledge. I knew the difference wasn't that huge.

But yes, if your electrical is that bad, you're fucked.

 

[n2audio 5,000+ posts]

Why does even the DMM method insert the caveat to not use full volume?

It doesn't. Neither does a scope.

If a person is so dense as to blast their system into excessive distortion/clipping et al and leave it there long enough to cause damage -- they deserve blown speakers, and I hope they're not warrantied.

Ignorance, we can try to fix -- stupid however, is here to stay.

 

[The_Quiet_One 10+ year member]

Square waves are what we would call distortion or clipping. Good way to blow up dem woofers or any speaker for that matter. Square waves can be introduced through HU or from overdriving the amp. That's why most guides and poeple suggest using a lower HU volume to set gains; you don't want to amplify an already clipped signal.

 

[Kadenj]

No - there's not. We want the power out of the amp to be close to clipping when the HU is close to clipping. There's no reason for it to be any more complicated than that.We're measuring AC rms voltage. Do this with a tone and any functional DMM it will work out just about perfectly.

It is ridiculous that some people on this forum want to elevate setting a gain to some sort of precision laboratory project.

Great is subjective, but adequate isn't. The DMM method is certainly adequate. Personally, I've been setting my gains by ear for years (and years), but a DMM and a test tone is all it takes for a total amateur to set a gain with plenty of accuracy to keep the speakers/subs from seeing excessive clipping.

If by "a lot" you actually mean "very little", then i guess it's "a lot".

Not any head unit I've ever encountered, or heard of.

Besides -- so it clips a little...if you can hear at all, and the clipping is bad enough to present a problem at high volume it should be plainly audible. Just reset the gain with the volume a little lower -- problem solved.

This isn't rocket science.

//content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif

I'm curious on how this might come about.

To summarize "possible pitfalls" -- essentially, none.

Thanks a bunch n2audio, i appreciate you correcting any misleading information //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

So i got the new amp this afternoon. I hooked it all up, except for the speakers, and tested voltage from the speaker terminals on the amplifier, but i simply Could Not Get a good reading. Now i'm not very familiar with the different settings on a DMM but i was on the 200 V setting (and YES I KNOW i should just go research that and not ask you guys for simple ****) So i don't exactly know that i was doing it correctly but i digress. I couldn't set the gain using the dmm, so i set it by ear, and im pleased with it, but i really want to make sure it's Safe, and if there is a way to make everything sound more CLEAR (Which right now it's sounds very clear, but i'm just not sure it's at it's clearest) i really want to know how to do it properly. There are a few knobs that i don't completely understand as well. The Punch EQ (Which is associated with the knob i don't have connected yet) THen there is an Infrasonic filter hz knob, from 15-40hz, then another filter i think from 50-200 hz. Where should i set THESE knobs, because i feel like when i move them around i'm losing certain ranges, and i'm just not sure how to know where to put them to get the max range and max quality. Sorry if this is a little much to ask haha //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[The_Quiet_One 10+ year member]

Lol, misleading information? Ok, I'll bow out and let the "experts" help you out with your further questions. @n2audio @fatboytyler

 

[Kadenj]

[quote name='Souldrop']Lol, misleading information? Ok, I'll bow out and let the "experts" help you out with your further questions. @n2audio @fatboytyler[/QUOTE]

i didn't even get through reading everything when i posted that, but it's huge so i didn't want to rewrite it and ****, anyway, i really don't CARE who's e-peen is bigger man, i just want Correct information, and if a general idea is what i am shooting for, than all of the specifics aren't quite as important. You are right i should be careful of my clipping, but i am not going to fry these woofers, and in fact wont even be pushing them., I went out into the middle of a field today and fiddled with the measurements. i Never went above 3.5 out of 11 on my gain, because I am trying to be cautious. what i said was not at all meant to offend you or anybody else, i just appreciated that he put it simply and did not over complicate. I just want some friendly advice, from whoever feels like submitting it, it's not about who's saying what.

 

[fatboytyler]

[quote name='Souldrop']Lol, misleading information? Ok, I'll bow out and let the "experts" help you out with your further questions. @n2audio @fatboytyler[/QUOTE]

And what makes you any better than us? Yes some of my information was wrong, but I admitted it. There's no need to get into the science of audio and electrical systems to do a basic everyday audio build. If he wants to go further he'll start to research himself as well.

 

[Kadenj]

And what makes you any better than us? Yes some of my information was wrong, but I admitted it. There's no need to get into the science of audio and electrical systems to do a basic everyday audio build. If he wants to go further he'll start to research himself as well.

bros! it's all good!

 

[The_Quiet_One 10+ year member]

It's all good. I try and give correct information (more of it than most people want) and he was giving incorrect information regarding AC current and I have issues with that. If he had said just ignore all the technical stuff and gave you sound advice I would have been fine. Summary of all my posts.

As long as you are careful setting gains with dmm you should be fine (sounds like you are) If it starts sounding or smelling bad means lower volume/gain. Is your box ported?

 

[fatboytyler]

bros! it's all good!

That was my last comment. Just wanted to explain why I dais what I said. I wish you the best of luck in your audio adventures and hopefully you'll get into it (super addictive) and start towards the big boy system route one day. But if not, you'll enjoy it regardless.

 

[Kadenj]

It's all good. I try and give correct information (more of it than most people want) and he was giving incorrect information regarding AC current and I have issues with that. If he had said just ignore all the technical stuff and gave you sound advice I would have been fine. Summary of all my posts.
As long as you are careful setting gains with dmm you should be fine (sounds like you are) If it starts sounding or smelling bad means lower volume/gain. Is your box ported?

Yes it is ported in the center.

this is essentially it, except my P3's have the kevlar reinforced faces,