Will 400 wrms be enough?

[pmureika 31]

Do you think 400 wrms will be enough for a daily driver?

 

On a IA Lethal injection rated at 1000 wrms.

[S.DeYoung 968]

Short answer, yes

[pmureika 31]

Short answer, yes

I figured that much.

 

Will it affect sound quality?

[Sencheezy 689]

 

Short answer, yes

I figured that much.

 

Will it affect sound quality?

 

 

no

[95Honda 486]

The sound quality will be better with 400 watts vs. 1000 watts.

[Impious 1,476]

The sound quality will be better with 400 watts vs. 1000 watts.

Word. Less power means there is less excursion so the driver will remain further within it's linear range, creating less distortion.

[altoncustomtech 773]

 

The sound quality will be better with 400 watts vs. 1000 watts.

Word. Less power means there is less excursion so the driver will remain further within it's linear range, creating less distortion.

 

 

While this does make a great deal of sense to me it also seems a little against the grain from what I typically see with SQ setups.  It seems a lot of SQ oriented setups run several times the rated power of the drivers to keep the peaks from the dynamics of the music clean and distortion free.  I believe you mentioned running 600 watts per channel to the Bravox 603CF's when you were running them.   Yet it stands to reason that it's pushing the driver beyond it's linear limits to do so.  How does one find the happy medium?  As I'm diving deeper into the SQ arena questions like this one perplex me.

[Impious 1,476]

There is a difference between having available headroom for dynamics and actually applying higher average power. In this example, if he were using a 1kw amp and setting it up in such a manor to utilize the majority of that power he wouldn't have much in the way of "headroom" since he would be using most of what the amp had to offer for the music. On the other hand, if he were using a 1kw amp but set the system in such a manor that the average power was similar to that of the 400w amp then the difference would be available as "headroom" for dynamics. I was under the assumption his question was in relation to the former rather than later.

I guess if you haven't yet read the thread I wrote about amplifier headroom.

[95Honda 486]

Meh.  Dynamics are important, but that not important.  The whole you need "XXXXX watts to hear a pin drop to an orchestra blah blah" is a pile of shit and a marketing gimmick...

 

There is a reason the best sounding amplifiers in the world are usually less than 100 WPC, because they sound good, not because they have a ton of power.  Same goes for high end speakers...

 

If at any time you even approach a drivers limit, you are no longer in the SQ realm, period...

 

Remember, car audio is 90% BS and 10% science, lol...

[altoncustomtech 773]

I've read that thread several times and just went back to read it again to be sure I wasn't thinking out of turn and I don't believe I am. I am referring to the idea of using a 1,000 watt amp at a 400 watt level for the purpose of headroom. Applied correctly the amp would likely be powering a speaker with a power rating at or near that 400 watts, yes, no, does that even matter? As stated before my confusion comes at when the dynamic peak or crest of the music is played couldn't the extra output (headroom) drive that speaker beyond its linear limits? Without knowing with certainty where in its travel the driver starts to become nonlinear and how much power it takes to move it to that point it would be a possibility correct? From that point then can one not assume that the distortion one meant to avoid from clipping with the extra headroom was just traded for distortion from moving the driver to the point of nonlinearity?

I'm not doubting the usefulness of having the headroom, and I'm probably missing another important point somewhere but that's where I'm coming from. Dear god I overthink everything, lol.

[j-roadtatts 1,129]

I was under the impression that with a clean signal and the proper xover settings that a speaker would benefit from the extra headroom? As I have heard Brad give the formula for the load placed on the amp for dynamic peak's, I am interested in the scientific answer. 

[95Honda 486]

The scientific answer is in order to use all that "headroom" that is supposedly necessary you would need to listen to your system at full tilt in order for it to sound good...  That is ridiculous...

 

Case in point, Sterophile's "Best sound at CES 2014" entries.  These are the best sounding systems in the world, period.  There is no mobile audio systems that can even approach what you hear with these.  One thing to notice is, about half these systems are 100 watts or less...  Some as little as 10 watts...  Yes there are high power amps too, but not the majority...  You don't have to have a ton of power for fidelity.  You only have to have a ton of power to play loud.

 

By the way, as someone who worked for a manufacturer that built high end equipment and went to CES many years, nobody plays these systems at levels that tap the amps out...

 

When I worked for Audioprism in the mid 90's we had a Stereophile top 10 best sound at CES entry 2 years running, with 30 watts per channel... 

[j-roadtatts 1,129]

I am referring to dynamic peaks in music at any volume.  I run 3.5" FRer's on 10 watts for my mids/highs so am aware its not just at full tilt on high power. 

[95Honda 486]

The point I am trying to make is you don't need all that power to sound good, period.  The whole headroom requirement gets blown way out of proportion...

[95Honda 486]

 Especially with the compressed music 99% of us listen to 99% of the time...

[95Honda 486]

Additionally, having a low noise floor will do more for dynamic range than power.  This is true for Audio, RF, etc...

[j-roadtatts 1,129]

I've read that thread several times and just went back to read it again to be sure I wasn't thinking out of turn and I don't believe I am. I am referring to the idea of using a 1,000 watt amp at a 400 watt level for the purpose of headroom. Applied correctly the amp would likely be powering a speaker with a power rating at or near that 400 watts, yes, no, does that even matter? As stated before my confusion comes at when the dynamic peak or crest of the music is played couldn't the extra output (headroom) drive that speaker beyond its linear limits? Without knowing with certainty where in its travel the driver starts to become nonlinear and how much power it takes to move it to that point it would be a possibility correct? From that point then can one not assume that the distortion one meant to avoid from clipping with the extra headroom was just traded for distortion from moving the driver to the point of nonlinearity?

I'm not doubting the usefulness of having the headroom, and I'm probably missing another important point somewhere but that's where I'm coming from. Dear god I overthink everything, lol.

Thanks for taking the time to elaborate 95. I understand the math myself but can not word it as elegant as yourself or Brad. SO I was hoping to get Mr.Altons question answered is honestly my reason for posting.

 

And yes I have read the pinned thread on headroom in the tech section.

 

I also have a large collection of CD's and do my tuning with them.

[95Honda 486]

Just think about this.  You are talking a daily driver, right?  So you will be listening while you drive, right?  Lots of road noise...

 

You could (A) increase you system output level potential 10db while trying not to be increasing distortion (this is a LOT! hard to do...)

 

Or you could (B) lower the noise floor in your vehicle 10db (completely doable with the right treatments)...

 

Both would give you same increase in dynamic range.  I would choose option (B) personally...

[j-roadtatts 1,129]

That's a good way to look at it without over thinking it. lol

 

 

As far as the THD distortion of the amp  vs "nonlinearity" of the driver, they are different things.

 

 

Please ask if these answers haven't summed it up for you Mr.Alton.

[j-roadtatts 1,129]

Was short on time with my last post but wanted to add.

 

As far as drivers handling more power than rated, you should understand this from working with subwoofers Alton. For each octave above fs the driver plays it should thermally raise the rms rating x2. So in other words, higher frequency's don't require as much xmax as long as they are filtered right. A good example for you would be model a driver with whatever power you want to see and look at the excursion plot with the filters in place. Should give you an idea. 

[Impious 1,476]

I've read that thread several times and just went back to read it again to be sure I wasn't thinking out of turn and I don't believe I am. I am referring to the idea of using a 1,000 watt amp at a 400 watt level for the purpose of headroom. Applied correctly the amp would likely be powering a speaker with a power rating at or near that 400 watts, yes, no, does that even matter? As stated before my confusion comes at when the dynamic peak or crest of the music is played couldn't the extra output (headroom) drive that speaker beyond its linear limits? Without knowing with certainty where in its travel the driver starts to become nonlinear and how much power it takes to move it to that point it would be a possibility correct? From that point then can one not assume that the distortion one meant to avoid from clipping with the extra headroom was just traded for distortion from moving the driver to the point of nonlinearity?

I'm not doubting the usefulness of having the headroom, and I'm probably missing another important point somewhere but that's where I'm coming from. Dear god I overthink everything, lol.

First realize how little excursion matters over the entire bandwidth. It really only becomes a factor at the lower end of a driver's bandwidth. So for the majority of the midrange, treble and upper bandwidth of a midbass and subwoofer excursion is relatively minimal. You would thermal a driver before excursion really comes into play outside of the low end of the bandwidth for each driver, therefore the excursion related non-linearity doesn't really apply over a very wide spectrum. With regards to the thermal aspect, those dynamics are transient in nature and don't last long enough to really push the drivers into thermal issues.

But if you, for example, have a driver that is driven to Xmax with 100w and you are listening at an average level of 10w with a source that has a 10db crest factor than the peaks would not push the driver past it's linear limits (100w) but a 50w amplifier would be asked to provide double the power. You can scale this example up or down depending on circumstances. If you are really rocking it out a little more at 20w average power and a source with 10db dynamics then the amp is asked to produce 200w. Or if you happen to be listening to more dynamic music. Are there circumstances where you might exceed Xmax? Maybe, over a VERY narrow bandwidth. Is that worth compressing the dynamics over a potentially wider bandwidth? That's up to the user to decide. Some say no.

My opinion is really that power is so cheap why would you want it to be the limiting factor in your system? If you have a 75w and a 150w amp both in your budget, why not get the extra 3db of headroom for the system? I'd prefer power to be something I don't need to think about. Turn the knob and the power is there, let the drivers decide when it's too loud. Especially when you're pushing the system because that's when we are looking to get the best performance and most enjoyment out of it, and that's when you will need that extra headroom. I'm not saying everyone needs to run the power I had. The 600w per side I was using was admittedly overkill and I actually used nowhere near that much power. But I got the amps for $100 each so why the hell wouldn't I buy them. In terms of flexibility the possibilities were endless. I could do anything I wanted with those amps and never have to worry about power.

Sure in home audio a lot of systems don't use much power....but at the same time they don't have the 70db noise floor to overcome, and they have the space for more efficient enclosures. If you can get by with an average power of 3w then that 30w amp provides 10db of headroom. In car audio I don't think that power is going to cut it for a lot of us. On the other hand there are also 500w monoblocks that guys in home audio use to power each tower.

[altoncustomtech 773]

Thank you guys for the answers to the questions.

 

 

Brad you seemed to understand exactly where I was coming from.