Why do I never see high efficiency subwoofers used for SPL purposes?

[todd.brust 29]

Let me start out by saying that I have been out of the car audio game for some time, and I have never been as concerned with SPL as much as I have been with overall sound quality.  It has been a mystery to me for some time as to why no one uses high efficiency subwoofers: for example a pro audio subwoofer.  If the main concern is to get loud, why is this option never mentioned or even discussed.

 

Many car audio subwoofers I see are in the range of 85-90 dB at 1 watt measured at 1 meter.  Maybe closer to low 90s for a large woofer.  On the other hand, many pro audio speakers have much higher efficiency, 95dB+ for 1 watt at 1 meter.  To me it seems that efficiency would be the name of the game for SPL.  If a woofer A has an efficiency of 90dB and woofer B has an efficiency of 93dB, it would take woofer A 2x the power to get the same SPL as woofer B.  

 

Okay, power is cheap, but what if we are talking a 90dB efficiency woofer(Woofer A) vs. a 99dB efficiency woofer(Woofer C)?  You would need roughly 8x the power the get the same SPL out of Woofer A vs. Woofer C.  1 watt vs 8 watts is no big deal, but what about 100 watts vs. 800 watts, or even better yet, 1000 watts vs. 8000 watts?

 

This all plays out well on paper and in theory, but I do realize that there are real world considerations and variables to take into account (enclosure alignment size and tuning, cabin gain, frequency, power compression, etc), not to mention the lack of low frequency extension of many high efficiency woofers and subwoofers and power handling compared to some subwoofers.

 

Maybe I am misguided by my own thoughts, but either way I am interested in what people have to say about this topic either way.  I realize audio in general is a compromise, but I’m interested to see how people weight pro vs. con for this specific issue.

Todd

[SpeakerBoy 64]

Seems to me, it's because the lower you go, the more displacement is needed. Pro woofers are far more efficient, but even high displacement pro drivers don't have enough throw to keep up down low (ie, LMS 5150 vs the Ultra, one is much stronger 40+ and one is much stronger <40).

My uneducated $0.02

[Aaron Clinton 2,372]

I think much of it has to do with how the market has changed.  Power is cheap and cheaply built.  Along with the average user getting younger and less experienced.  So sub woofers have to be built much tougher now then even just 7 years ago.  So when you give more power to less experienced users.... efficiency is a thing of the past.  Meaning it is not a factor that is part of the decision process anymore.  Some of it is just because it is about who has more watts in their car, but much of it is Hoffmans Iron Law.  The other two factors are in much higher demand than efficiency right now.

[SpeakerBoy 64]

I think much of it has to do with how the market has changed. Power is cheap and cheaply built. Along with the average user getting younger and less experienced. So sub woofers have to be built much tougher now then even just 7 years ago. So when you give more power to less experienced users.... efficiency is a thing of the past. Meaning it is not a factor that is part of the decision process anymore. Some of it is just because it is about who has more watts in their car, but much of it is Hoffmans Iron Law. The other two factors are in much higher demand than efficiency right now.

People are speechless when you have a much louder, better sounding system with one quarter, or less, power than them.

It's a wonderful feeling

[todd.brust 29]

Seems to me, it's because the lower you go, the more displacement is needed. Pro woofers are far more efficient, but even high displacement pro drivers don't have enough throw to keep up down low (ie, LMS 5150 vs the Ultra, one is much stronger 40+ and one is much stronger <40).

My uneducated $0.02

 

I understand this, but in an environment where cabin gain plays a huge role in low frequency extension, is it necessary to reach lower than 30 hz for most music?

[todd.brust 29]

I think much of it has to do with how the market has changed.  Power is cheap and cheaply built.  Along with the average user getting younger and less experienced.  So sub woofers have to be built much tougher now then even just 7 years ago.  So when you give more power to less experienced users.... efficiency is a thing of the past.  Meaning it is not a factor that is part of the decision process anymore.  Some of it is just because it is about who has more watts in their car, but much of it is Hoffmans Iron Law.  The other two factors are in much higher demand than efficiency right now.

 

I think you just answered my question!  Case closed

[SpeakerBoy 64]

Seems to me, it's because the lower you go, the more displacement is needed. Pro woofers are far more efficient, but even high displacement pro drivers don't have enough throw to keep up down low (ie, LMS 5150 vs the Ultra, one is much stronger 40+ and one is much stronger <40).

My uneducated $0.02

I understand this, but in an environment where cabin gain plays a huge role in low frequency extension, is it necessary to reach lower than 30 hz for most music?

I mean, not to everyone. Some people are content with prefab porteds, and that kind of tuning, even a little lower would probably be great for a pro driver. But my flavor is slowed, so I appreciate the <40hz violence

[todd.brust 29]

 

 

Seems to me, it's because the lower you go, the more displacement is needed. Pro woofers are far more efficient, but even high displacement pro drivers don't have enough throw to keep up down low (ie, LMS 5150 vs the Ultra, one is much stronger 40+ and one is much stronger <40).

My uneducated $0.02

I understand this, but in an environment where cabin gain plays a huge role in low frequency extension, is it necessary to reach lower than 30 hz for most music?

I mean, not to everyone. Some people are content with prefab porteds, and that kind of tuning, even a little lower would probably be great for a pro driver. But my flavor is slowed, so I appreciate the <40hz violence

 

 

Fair enough.  There is hardly and argument for personal preference.

[shizzzon 461]

Efficiency ratings may peak at 1khz.. you do not know which frequency or

range is the most efficient and they won't tell you

Because of this, we pay no attention to efficiency alone

because without seeing an efficiency graph, the spec is pointless.

[SpeakerBoy 64]

For comps, I'd have to lean towards efficiency.

But man would I love to run a 159.9 at like, 25hz

[Aaron Clinton 2,372]

Gone are my hey days of Cerwin Vega - Vega's or Rockford Fosgate - Power's of huge ported boxes and maybe a 250aII or 500a1 on a pair of subs.

[j-roadtatts 1,129]

The Gcon gives the UFO BTL a run for it's money on 1/5 the power.

[SpeakerBoy 64]

The Gcon gives the UFO BTL a run for it's money on 1/5 the power.

That's some low efficiency sarcasm I sense, isn't it

Edited February 13, 2014 by SpeakerBoy

[j-roadtatts 1,129]

No sir. I own a 15" Dcon in a 4 cu ft enclosure with 82 in port tuned to 35hz and an fully loaded UFO BTL in 5 cu ft enclosure with 80 sq in tuned to 32hz. In different vehicles of course. The Dcon has been in three different ride's in the last year. The Btl is in my ride of course. The Dcon is just as impressive as the BTL though. 

[j-roadtatts 1,129]

RE-READ Hoffman's IRON law please.

[kirill007 52]

Efficiency ratings may peak at 1khz.. you do not know which frequency or

range is the most efficient and they won't tell you

Because of this, we pay no attention to efficiency alone

because without seeing an efficiency graph, the spec is pointless.

I'm pretty sure this is the only reason, along with people wanting subwoofers that play much lower,

[j-roadtatts 1,129]

There is a difference between low and loud. I believe most competitors find their vehicle's peak much higher than 30hz. Speakers are tested at one tone only, 1k hz. That's why the pro audio driver is louder in the manufacturers post T/S parameters. 

 

 The only reason to look at posted SPL rating's when comparing driver's is in regards to Hoffman's Iron Law.

[TML_LUNCHBOX 4]

 

Seems to me, it's because the lower you go, the more displacement is needed. Pro woofers are far more efficient, but even high displacement pro drivers don't have enough throw to keep up down low (ie, LMS 5150 vs the Ultra, one is much stronger 40+ and one is much stronger <40).

My uneducated $0.02

 

I understand this, but in an environment where cabin gain plays a huge role in low frequency extension, is it necessary to reach lower than 30 hz for most music?

 

X2 on low frequency response. I don't understand why people want to play 25hz or even less. There's almost no music commercially available that has that low of an extension. Only songs that do are rebass from people like decaf and have poor quality. So much energy wasted to do big numbers at low frequencies. The window of frequencies I like are from 30-50hz for the sub stage. 

[SpeakerBoy 64]

RE-READ Hoffman's IRON law please.

I just assumed you were giving me shit. It's hard to tell on here sometimes.

[j-roadtatts 1,129]

Look up the "Equal Loudness Curve" and you will see that a big gain is needed on both ends of the octave spectrum for your ear to hear the octave's EQUALLY.

[TML_LUNCHBOX 4]

There is a difference between low and loud. I believe most competitors find their vehicle's peak much higher than 30hz. Speakers are tested at one tone only, 1k hz. That's why the pro audio driver is louder in the manufacturers post T/S parameters. 

 

 The only reason to look at posted SPL rating's when comparing driver's is in regards to Hoffman's Iron Law.

Yes and no. Iv been competing for many many years now with multiple mwspl championships with multiple 2nd, 3rd, 4th, and 5th place national trophy's. MWSPL, Bass Race, MECA, USACI these organizations that I compete in offer musical class's. Mainly I compete in MWSPL and they do offer more music class's then any other. Like a lot of others competitors now days, we build and compete for musical class's and just about every one that owns what I call a "super system" peaks from 30-45hz and do big numbers. But yes the burp vehicles are geared for 60-70hz. The new trend in the lanes is long duration musical "torture tests" but in a loud and low situation. Nothing like death match in db drag may years ago where you can play your 70hz track on repeat for 5 mins. My system does over 160db on the dash at 36hz musically with only 700sq of cone area. I peak low and don't have a whole lot of cone area and that number seems hard to believe but I do dominate my class's in mwspl and for USACI I should have gotten my points and took home the sb4 with just my 4 15s this past year. Would have just beat AMI Andrew by about .5 db or at least that's what I know from seeing his scores to mine. Andrew is a buddy of mine and he is loud not taking anything away from him.

Edited February 13, 2014 by TML_LUNCHBOX

[j-roadtatts 1,129]

No sir. I own a 15" Dcon in a 4 cu ft enclosure with 82 in port tuned to 35hz and an fully loaded UFO BTL in 5 cu ft enclosure with 80 sq in tuned to 32hz. In different vehicles of course. The Dcon has been in three different ride's in the last year. The Btl is in my ride of course. The Dcon is just as impressive as the BTL though. 

DAMN, I definitely can't piss that far brother.

 

I explained the physics and also gave examples of the law being applied to level the playing field. I am from back in the day when NO music played low. FYI

[Tenacious 32]

According to most sensitivity ratings, it would take thousands of watts to break 120dB... This should tell you that we need to disregard sensitivity ratings for subwoofers. 

[j-roadtatts 1,129]

It is 90% install, 10% beer.

[kirill007 52]

According to most sensitivity ratings, it would take thousands of watts to break 120dB... This should tell you that we need to disregard sensitivity ratings for subwoofers. 

You are forgetting acoustics my friend.