Why don't competitors use pro audio subs?

[audioholic 5,000+ posts]

Sufficient power for the application is important. Absolute power less so.
That and I never said power wasn't a factor. I said it was the least efficient means. You can increase power two fold and gain a maximum of 3db (less power compression which can become significant at these power levels), which means you also have to upgrade the power source to supply twice the power to the amplifier and the entire system, from wires to amplifiers to voice coils, has to dissipate twice as much heat.......or you can increase the sensitivity of the system by 3db, for example. And this is before we get into the details of power compressions effect on the system.

Is it "better" to reach Xdb with 2kw or 1kw? Why is reaching Xdb with 2kw more impressive or more important than reaching Xdb with less than 2kw?

This is the point I was getting at.

Hoffman's Iron Law states sometimes you'd rather reach Xdb with 2kw than with 1kw. Smaller enclosures mean more space to utilize for more cone area, thus increasing over all decibel levels. Efficiency is not the end-all bonus you seem to be implying.

 

[Ctesibius 10+ year member]

In SPL, power is one of the things you need. They may be efficient, but if you cant give them the power that any other SPL sub can take, you wont see the DBs that you will with thousands and thousands of watts on a less efficient sub. That answers his questions as to why they dont use pro audio subs.

More power is one of the things you need in a less efficient design.

If what you were saying is true then, for example, 100w to a system design with 90db sensitivity would be louder than 1w to a horn setup with 110db sensitivity. Ignoring power compression, they would each generate 110db. If you consider power compression, the horn setup would easily be louder.

Of course there are trade-offs to each we could discuss, but those aren't really relevant to the point being made.

 

[Ctesibius 10+ year member]

Hoffman's Iron Law states sometimes you'd rather reach Xdb with 2kw than with 1kw. Smaller enclosures mean more space to utilize for more cone area, thus increasing over all decibel levels. Efficiency is not the end-all bonus you seem to be implying.

More cone area does not inherently imply more output, depending upon the various enclosure/loading techniques being utilized in each individual application. For example, the use of an efficient dual sub bandpass enclosure compared to a quadruple sub sealed system that could consume the "conserved" space.

Also, Hoffman's law says that if you want efficiency in a smaller enclosure volume, you'll give up low frequency extension. Most SPL competitors aren't overly concerned about low frequency extension.

 

[audioholic 5,000+ posts]

More cone area does not inherently imply more output, depending upon the various enclosure/loading techniques being utilized in each individual application. For example, the use of an efficient dual sub bandpass enclosure compared to a quadruple sub sealed system that could consume the "conserved" space.
Also, Hoffman's law says that if you want efficiency in a smaller enclosure volume, you'll give up low frequency extension. Most SPL competitors aren't overly concerned about low frequency extension.

I wasn't suggesting more cone area always wins no matter what. I was suggesting for a given enclosure/install type, more cone area will always be beneficial. You are trying to compare a bandpass to a sealed setup, hardly my point in suggesting smaller enclosures mean more room for more cone area. How about comparing apples to apples if you are going to contradict my example? Wouldn't you rather run an 18" in a bandpass setup rather than a 15"? Even if it means needing more wattage? I know SPL guys would. The simple fact that serious SPL guys today are in fact going this route merely substantiates what Im saying. Are we seeing wattage stay relatively the same, while efficiency in raw speakers goes up? No, we are seeing efficiency (of the speaker) drop while wattage is going through the roof.

Hoffman's Iron Law is not only for

 

[Ctesibius 10+ year member]

This is going to go around and around again. So, I'll concisely state my initial point once more, hopefully to clarify a final time.

Power is the least efficient means by which to increase output. After factoring in the necessary increase in power supplied to the system, the increase in heat loss in all of the equipment, and the power compression occurring in the drivers......it's simply not an efficient method. It is better to maximize the efficiency of the subwoofer system first (not necessarily the driver itself). If you've noticed, most of the very high output systems are able to hit extremely high numbers on low power....because it's an efficient system. Once at that level, they utilize power to gain the last few tenths. Most of the people on this forum are not at that level. They focus on power first and system efficiency is an after thought. That is the wrong way to go about things.

Nate Munson, for example, was at nearly 170db with a single 10 and around 10kw of power, although IIRC he was also known to use 5kw at some competitions. If you work backwards, and for the moment ignore power compression, the mathematics says that's 130db @ 1w. After you consider power compression, it probably would have been considerably louder @ 1w. That is probably the best example of the point I am trying to convey.

And if you reread my posts in this thread, I never even promoted or supported the idea of using a high sensitivity driver. I started by simply pointed out that increasing power is not an efficient method.

 

[audioholic 5,000+ posts]

This is going to go around and around again. So, I'll concisely state my initial point once more, hopefully to clarify a final time.
Power is the least efficient means by which to increase output. After factoring in the necessary increase in power supplied to the system, the increase in heat loss in all of the equipment, and the power compression occurring in the drivers......it's simply not an efficient method. It is better to maximize the efficiency of the subwoofer system first (not necessarily the driver itself). If you've noticed, most of the very high output systems are able to hit extremely high numbers on low power....because it's an efficient system. Once at that level, they utilize power to gain the last few tenths. Most of the people on this forum are not at that level. They focus on power first and system efficiency is an after thought. That is the wrong way to go about things.

Nate Munson, for example, was at nearly 170db with a single 10 and around 10kw of power, although IIRC he was also known to use 5kw at some competitions. If you work backwards, and for the moment ignore power compression, the mathematics says that's 130db @ 1w. After you consider power compression, it probably would have been considerably louder @ 1w. That is probably the best example of the point I am trying to convey.

And if you reread my posts in this thread, I never even promoted or supported the idea of using a high sensitivity driver. I started by simply pointed out that increasing power is not an efficient method.

I agree with your clarification, except to add one more thing. Nate Munson's 169.7 was not on the now current and standard TL. It was an AC meter iirc, just to place that score in a bit more of a proper perspective (several db less than today's TL would score it at).
But yes, SPL vehicles strive for maximum efficiency of the system, something I did not realize was in question, as I thought that was a given. They utilize space confinement, interior modifications including extreme deadening, sealing procedures, and even interior shape alterations dedicated to maximizing pressure nodes at specific points (depending on their class and organization) to increase system efficiency. But with that said, many of these alterations do not increase efficiency on a linear scale. Im not an SPL expert, but I do not believe your 1 watt estimation of SPL based on extrapolating Nate's score backwards gives a realistic idea of what he would accomplish with a 1 watt power input. Interior shape alterations, for example, do not yield as extreme of results with less initial pressure to manipulate. Never the less, his score set the sport, and indeed the entire industry, on its ear.

 

[Ctesibius 10+ year member]

But with that said, many of these alterations do not increase efficiency on a linear scale. Im not an SPL expert, but I do not believe your 1 watt estimation of SPL based on extrapolating Nate's score backwards gives a realistic idea of what he would accomplish with a 1 watt power input.

Dante claims his vehicle is 141db @ 1watt, and he's in the low 180's running full power w/ IIRC around 30kw (I believe he has four 7kw amps), which factors backwards to 135db @ 1w ignoring power compression.....so it sounds about right after factoring in the probable power compression to the mathematics.

So it's probably not a stretch.

EDIT: Dante also said in that post on termpro that the DD9918Z he uses has a 1w/1m sensitivity of 98db.

 

[gunz4me2 10+ year member]

The drivers listed are not really "pro-audio" drivers. They are very low end generic drivers for amateur garage band gear and wedding DJ's. Not the drivers your hearing at a concert or major event.
Most "Pro" subs are contracted custom production, and not easily available as retail components. You buy them in the cabinet as a complete sub. They try to keep thier drivers and some specs " proprietary". They cost thousands of dollars each.

I remember 10 years ago when a friend of mine replaced his four 18" Earthquakes with four 12" EAW folded horn sub cabinets. I said "There is no way you will get more bass from four 12" subs than you had with your four 18" subs."

Boy was I ever wrong.//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

He is now using those EAWs in his nightclub.

 

[audioholic 5,000+ posts]

Dante claims his vehicle is 141db @ 1watt, and he's in the low 180's running full power w/ IIRC around 30kw (I believe he has four 7kw amps), which factors backwards to 135db @ 1w ignoring power compression.....so it sounds about right after factoring in the probable power compression to the mathematics.
So it's probably not a stretch.

EDIT: Dante also said in that post on termpro that the DD9918Z he uses has a 1w/1m sensitivity of 98db.

I guess I just have to question why you are shifting the discussion away from the initial topic of the thread --> driver efficiency, towards a totally different topic --> system efficiency. I dont believe anyone questioned that system efficiency is an important factor. The question in this thread was, and always has been, driver efficiency. 'Why aren't high efficiency pro audio speakers used for SPL competition'. This has nothing to do with the topic you are trying to morph our discussion into, system efficiency. What Nate Munson's system does with low power really has very little to do with the thread topic, because as even you will concede, he did not use high efficiency speakers (as compared to pro audio). DD9510. Even his testing with other 'low efficiency' drivers like a W7 showed only a relatively low drop in over all system output, if you are thinking of suggesting the 9510 is a high efficiency unit.

Dante can claim his 99Z has a 98db sensitivity, but that certainly flies in the face of other top ranked SPL competitor's sub's efficiency (upper 80's to low 90's). And of course, we all know DD's reputation for not publishing realistic specs on their drivers (or none at all), so who knows what the Z's efficiency really is. Again, when looking strictly at speaker efficiency, and not deviating to the unrelated system efficiency, Hoffman's Iron Law states there are distinct advantages to low efficiency drivers using lots of watts. And again, the mere fact that SPL competitors DO use relatively low efficiency speakers, as opposed to higher efficiency pro audio units, points to my 'theory' being the correct one. If you want to argue system efficiency is crucial, by all means, go ahead... nobody is arguing against that point. Coupling a highly efficient system with relatively low efficiency speakers taking abuse from tons of watts very near enclosure tuning, is clearly the preferred combination for successful SPL rigs these days. Tens of thousands of watts (some bordering on a hundred thousand watts), multiple alts, huge banks of batteries... this has become the norm in serious SPL competition, and again only points to the fact that low efficiency speakers are successful, and power handling IS important in this venue.

 

[RAM_Designs 5,000+ posts]

good conversation guys!

 

[AudioAnonymous 10+ year member]

Didn't know SPL was so technical. I prefer the "just build it" theory.

 

[Ctesibius 10+ year member]

I guess I just have to question why you are shifting the discussion away from the initial topic of the thread --> driver efficiency, towards a totally different topic --> system efficiency. I dont believe anyone questioned that system efficiency is an important factor. The question in this thread was, and always has been, driver efficiency. 'Why aren't high efficiency pro audio speakers used for SPL competition'. This has nothing to do with the topic you are trying to morph our discussion into, system efficiency. What Nate Munson's system does with low power really has very little to do with the thread topic, because as even you will concede, he did not use high efficiency speakers (as compared to pro audio). DD9510. Even his testing with other 'low efficiency' drivers like a W7 showed only a relatively low drop in over all system output, if you are thinking of suggesting the 9510 is a high efficiency unit.
Dante can claim his 99Z has a 98db sensitivity, but that certainly flies in the face of other top ranked SPL competitor's sub's efficiency (upper 80's to low 90's). And of course, we all know DD's reputation for not publishing realistic specs on their drivers (or none at all), so who knows what the Z's efficiency really is. Again, when looking strictly at speaker efficiency, and not deviating to the unrelated system efficiency, Hoffman's Iron Law states there are distinct advantages to low efficiency drivers using lots of watts. And again, the mere fact that SPL competitors DO use relatively low efficiency speakers, as opposed to higher efficiency pro audio units, points to my 'theory' being the correct one. If you want to argue system efficiency is crucial, by all means, go ahead... nobody is arguing against that point. Coupling a highly efficient system with relatively low efficiency speakers taking abuse from tons of watts very near enclosure tuning, is clearly the preferred combination for successful SPL rigs these days. Tens of thousands of watts (some bordering on a hundred thousand watts), multiple alts, huge banks of batteries... this has become the norm in serious SPL competition, and again only points to the fact that low efficiency speakers are successful, and power handling IS important in this venue.

The world used to be flat.

Maybe guys like Dante are helping to show that it's round.

If your theory is correct, maybe you should question why one of the loudest guys in the world is using a single (supposedly) high efficiency driver with 1/3 of the power of many competitors.

And sufficient power for the application is important. Not absolute power, which was the point of my original comment in this thread after a few members commented on power. If absolute power were the most important aspect, than the guy with the most power would win every time. But that's obviously not the case.

 

[T3mpest 10+ year member]

The world used to be flat.
Maybe guys like Dante are helping to show that it's round.

If your theory is correct, maybe you should question why one of the loudest guys in the world is using a single (supposedly) high efficiency driver with 1/3 of the power of many competitors.

And sufficient power for the application is important. Not absolute power, which was the point of my original comment in this thread after a few members commented on power. If absolute power were the most important aspect, than the guy with the most power would win every time. But that's obviously not the case.

I'll agree with this whole heartedly. Alot of SPL competitors don't have a great grasp of physics. Most people will tell you it's impossible to model loud. Something tells me dante didn't just throw a bunch of boxes together and hope to hit a 180. I'd bet there was quite a bit of modeling done. Dante uses less power than alot of other vehicles and has piddly shit for cone area vs most setups. He's also in many cases 10db's louder than vehicles utilizing alot more speakers. Again, perhaps not the point of the entire thread, but I still felt the need to chime in.

 

[audioholic 5,000+ posts]

The world used to be flat.
Maybe guys like Dante are helping to show that it's round.

If your theory is correct, maybe you should question why one of the loudest guys in the world is using a single (supposedly) high efficiency driver with 1/3 of the power of many competitors.

And sufficient power for the application is important. Not absolute power, which was the point of my original comment in this thread after a few members commented on power. If absolute power were the most important aspect, than the guy with the most power would win every time. But that's obviously not the case.

As usual, you take my comments completely out of context to try and debunk them. Tell me where I said absolute power was the most important aspect. I stated power handling was important. I never claimed anything about absolute power, or said it was the 'most important aspect'. Nor did I refer to system efficiency in any of my replies. For a smart guy, you really seem to read my posts with your dunce cap on.

 

[I Like Waffle]

I just bought 2 pyramid pro audio drivers for 50 bucks, these mofos are BEEFY for what they are. 3" 4 layer coil, 4 spoke basket, high roll foam surroud, motor is pretty big too not sure what kind it is, also has a complete CF cone. Theyre in my car but ill get pics //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif