What is your minimum SPL requirement?

[ckirocz28]

I went to see the Ministry's final tour with the Revolting Cocks back in 2010 in a smaller venue in Detroit. The SPL was so freaking high my ears still ring to this day. I remember the bass being so intense that it hindered your breathing. The guitars and vocals were ear piercing even with ear buds. It was to the point to where I was in pain and didn't enjoy it (which is sad). I've been to nearly a hundred concerts and have never felt this way. I'm going to say this was about 115dB full range.

But, then I've been in clubs with booming bass approaching 130dB. It was an annoyance if you wanted to talk but by no means painful. Why is that? Does it have to do with the frequency your ear drums vibrate at given a specific amount on sound energy?

Ge0

That concert was probably more than 115 db, probably even more than 125 db.
No matter what the "experts" say to avoid being sued into oblivion, bass does not do as much damage or cause as much pain as midrange and highs at the same level. 150 db subs will hurt you while playing, but 150 db midranges will permanently deafen you, quickly.

[geolemon]

I definitely wear hearing protection these days at concerts, usually just those little foam ear plugs. I also have a fancier set for my motorcycle, supposed to be also good for concerts.
Damn, I would have loved to be at that Ministry/Revolting Cocks show - with hearing protection. I bet that was awesome. I only saw Ministry once, in the 90's, when Lolapolooza first started and was still good.

That was my point before about dB being used for anti-car-audio purposes, which sucks...
The whole premise behind "decibel laws" uses logic like "A jet plane taking off is 125dB! Some of these boom cars reach 150dB!"
Granted, they are NOT explaining that the dB scale is logarithmic, so that difference is WAY more than it looks like...
...but they also are NOT explaining the difference of frequencies - that high frequencies are much more damaging than low frequencies, or that low frequencies inherently penetrate and travel further (although that still may support their argument for the noise laws).

Doing a little web crawling, I didn't find anything simple like "the higher the frequency, the more damage", but I did find this bullet:

• Loss is always greater at the frequencies 3000-6000 Hz than at 500-2000 Hz. Loss is usually greatest at 4000 Hz. The 4000-Hz notch is often preserved even in advanced stages.

...so possibly, that means 4000hz (coincidentally that's right about dead center of the frequency spectrum, since it's logarithmic also) is the most damaging to our hearing, and as we move away from that - loud noises are less likely to hurt our ears? I don't know for sure. Definitely interesting and more complex than "X dB hurts your hearing!"

[Smitty]

This question came more out of deciding which subwoofer I want. Trying to determine how much I really need has raised many questions I never really thought about. 85-90db is about my limit when jamming and then I really can't go for long. I've never been to a concert and I have really good hearing. Most of my listening is my office at low volume on a 2.1 bookshelf system. So, do I really need a 12" subwoofer.

My current setup sounds good and is almost enough. I actually thought about a subless system. Currently the 8's in my doors will play to 30 hz but they really start to roll off fast around 40 hz.

As far as the sub choice Hoffman's Iron Law is really holding me back. I've always built more on the efficient side. I definitely want a seald enclosure. I don't have much room (probably less than 1 ft3)... and only have 300-400 watts.

A 10" would be easier to fit than a 12". If I never listen above 90 db... and even that is rare, do I really need a 12"?

[Cutaway]

This discussion brings up another interesting topic, maybe even it's "new thread". But when setting speaker output volume levels in the car, what SPL DB are you shooting for to level match each additional speaker to?

[preston]

A 10" would be easier to fit than a 12". If I never listen above 90 db... and even that is rare, do I really need a 12"?

No. What you really need is an 18". Or a 24" now that that's a thing !

Bigger is better if you can fit it. Doesn't mean you won't be happy with a 10", but given equal constraints (proper install, box size) the 12" will be better regardless of high dB. IMO.

[Smitty]

I am a fan of 12's and 15's even though I've built systems with single 6.5's and 8's. It just seems that even at lower volume levels, the larger subs in low Q enclosures can reach really deep with less effort. I know it's all in my head. 20hz at 100db is the same in a 10 or 15 correct?

[tfunk182]

I was wondering if anyone else uses dBA.
I'm really happy jamming at 85-90dBA in the car. More than that and I can only enjoy a song or two.
(using a handheld type II meter)

90dBA is about all my ears can handle. But if it's a great sounding recording I can go a little louder.

[NoDestiny]

This question came more out of deciding which subwoofer I want. Trying to determine how much I really need has raised many questions I never really thought about. 85-90db is about my limit when jamming and then I really can't go for long. I've never been to a concert and I have really good hearing. Most of my listening is my office at low volume on a 2.1 bookshelf system. So, do I really need a 12" subwoofer.

My current setup sounds good and is almost enough. I actually thought about a subless system. Currently the 8's in my doors will play to 30 hz but they really start to roll off fast around 40 hz.

As far as the sub choice Hoffman's Iron Law is really holding me back. I've always built more on the efficient side. I definitely want a seald enclosure. I don't have much room (probably less than 1 ft3)... and only have 300-400 watts.

A 10" would be easier to fit than a 12". If I never listen above 90 db... and even that is rare, do I really need a 12"?

Your 8s in your doors have a few flaws (assumingly). They are going to have a null somewhere, depending on distance. They likely have some resonance at higher volume. They probably don't play those lows as cleanly at higher volume. etc. With a subwoofer, you can cut them higher up, such as 60 or 80hz. Should clean them up a bit and give less rattle in the door. So there's one case for a subwoofer...

Size wise, a 8" vs an 18"... size doesn't really matter. The proper install does. At 1 cube... a single Dayton Ultimax 10" would be good. A cube is perfect for sealed. Models up with an F3 of about 40hz and an F10 of 22hz. Throw in cabin gain, probably a pretty flat response down to 20hz. (Sorry, I like the Dayton Ultimax series) I'm sure there are plenty of 10" and 12" options, but just make sure they work best with your airspace.

[geolemon]

Your 8s in your doors have a few flaws (assumingly). They are going to have a null somewhere, depending on distance. They likely have some resonance at higher volume. They probably don't play those lows as cleanly at higher volume. etc. With a subwoofer, you can cut them higher up, such as 60 or 80hz. Should clean them up a bit and give less rattle in the door. So there's one case for a subwoofer...

Just to clarify this fantastic point (correct me if I'm wrong, NoDestiny, not trying to misrepresent your points)...
NoDestiny isn't talking about your actual speakers, or even your install per se - it has to do with nothing more than the location of the speakers, and cancellation nodes that naturally occur from the wildly complex, and largely uncontrollable acoustical model of absorbtions and reflections that is "the acoustics of your car interior", and how sound bounces around your interior and ultimately arrives at your ears. Based on all the pathlength distances (both direct and reflected) from those speaker locations to your ears, it's very common to have acoustical "null" nodes that exist at 70Hz, at 150hz-ish, and a bunch up higher that are also location dependent.
You could install the most bad-ass midbass drivers in the world, cut your doors apart and make vented boxes tuned to 70hz that would make bassheads drool - and STILL not get 70hz output at your listening position.

One technique that seems counter-intuitive for SQ is to play your sub up past that null - having the sound coming from a different pathlength (trunk) could resolve that null.
But there are other techniques - for example, I'm going to try to tackle this by using my rear door locations for more midbasses - again, different pathlength is possible from there as well, hoping to resolve the NULL that way. And besides, besides this use, I have ZERO use for rear door locations - just terrible things that Satan must have designed in. So if I can actually use them productively - wow, why not?

Size wise, a 8" vs an 18"... size doesn't really matter. The proper install does. At 1 cube... a single Dayton Ultimax 10" would be good. A cube is perfect for sealed. Models up with an F3 of about 40hz and an F10 of 22hz. Throw in cabin gain, probably a pretty flat response down to 20hz. (Sorry, I like the Dayton Ultimax series) I'm sure there are plenty of 10" and 12" options, but just make sure they work best with your airspace.

Touching on the "proper install does", just want to make sure "proper install" considers "proper engineering". Especially with midgrade and low-end manufactuers, you will find that the specs aren't all that balanced. When you look at most 8" and 10" subs (in any given manufacturer's line), you'll see the Qts to be lower and Fs to be higher, making for more ideal vented-box subs. With their low mass and relatively more powerful motors, and even the smaller cones that likely have fewer breakup modes - no doubt those would work better for also playing dual-duty reaching up into the midbass range.
...on the other hand, as you move up the size range - I usually find either the 10" or 12" to be the one with that mid-level Qts and Fs that workout to be "equally good in vented or sealed", and so you could argue the motor and mass start to get a little compromised for midbass duty... but I mean really most would probably still be fine realistically playing well through midbass octave...

But when you get much bigger (and again, yeah, in pro-audio you DO have those lower-Xmax, bigger-magnet-diameter huge cone midbass drivers, but those engineering constraints are usually the opposite of what we'd shop for for SUBwoofers), you tend to find the Qts getting up there - in some cases damn near 1.0... and that big-ass cone, with all that moving mass - usually a really low Fs, and probably cone breakup modes in the midbass range that nobody in engineering cared about, because that wasn't the design intent.

Ironically, this might be a place where SPL subs could perform well - they usually have abuse-friendly stiff cones, higher Fs, lower Xmax, lower Qts, higher BL... everything that makes them suck for daily driver subs definitely could make them perform decently well into the midbass range... if you are OK with NEEDING to feed them 1000+ watts just to start to hear them And that's sometimes where specs can be a little deceiving - subs that "work well" in small enclosures, they won't be as efficient. That's Hoffman's Iron Law, and it's an "Iron Law" for a reason.

But that little peeve of mine also (kids buying SPL subs for daily drivers and expecting them to be great) - to me it IS a "the proper installation matters", because I DO consider proper selection of components to be a "proper installation" consideration... It's why I'm a die-hard DIY enthusiast, encourager, and supporter.
Yeah, a miracle worker installer CAN make a subwoofer do things other than what it was engineered to do - but that installer is fighting against the engineering, rather than being able to use proper engineering to their advantage. Even that installer won't get the best results they are capable of, their results will always be better if they had the ability to pick a better subwoofer, meaning "with parameters that were more conducive to their installation engineering goals". No installer wants their results to be blunted by the inherent limitations of somewhat incompatible products they had no influence in selecting.

[Smitty]

Your 8s in your doors have a few flaws (assumingly). They are going to have a null somewhere, depending on distance. They likely have some resonance at higher volume. They probably don't play those lows as cleanly at higher volume. etc. With a subwoofer, you can cut them higher up, such as 60 or 80hz. Should clean them up a bit and give less rattle in the door. So there's one case for a subwoofer...

Size wise, a 8" vs an 18"... size doesn't really matter. The proper install does. At 1 cube... a single Dayton Ultimax 10" would be good. A cube is perfect for sealed. Models up with an F3 of about 40hz and an F10 of 22hz. Throw in cabin gain, probably a pretty flat response down to 20hz. (Sorry, I like the Dayton Ultimax series) I'm sure there are plenty of 10" and 12" options, but just make sure they work best with your airspace.

Yes, you and Geo are correct and I knew that going in. I was very surprised not to get hammered by the 70 hz null. There are nulls like any system, but not the tremendous kick in the crotch the 70 can be at times.
Yes, the sub bass does have trouble below 60hz. It's why I decided to let it roll off at 40hz instead of boosting the lows.

It doesn't sound bad, just doesn't get to the point of "subless" happiness. I had a crazy idea that I could have two eq presets and be able to have larger sub in the rear which could be removed when I needed cargo room. It does appear that stealth in corner will have to be the goal.

I do like Dayton drivers, I have just never used an Ultimax. I model them some an see. If i decide to dump the budget idea, it will probably be a Scanspeak 30W