ok told me how they do this!! seems not possible!!! I got 2 tham12 and I never hit 146dB in my room. I also got 2 15" tuned to 35hz and again, never 146dB!!
These guys hit 146dB with a single 8"... how can they do this?
https://www.youtube.com/watch?v=Cdbn03zAALc
the 146dB is with a DD 1508a ( 2400W MAX and 300-600W Continuous)
I'm not able to do any simulation that is "flat" that can reach more than 95dB with this 8" sub.
Is it possible?
thanks,
B-Freak
These guys hit 146dB with a single 8"... how can they do this?
https://www.youtube.com/watch?v=Cdbn03zAALc
the 146dB is with a DD 1508a ( 2400W MAX and 300-600W Continuous)
I'm not able to do any simulation that is "flat" that can reach more than 95dB with this 8" sub.
Is it possible?
thanks,
B-Freak
I only skimmed the video, admittedly, because I really hate they way the car audio crowd does testing.
Those numbers aren't hard to hit in what I've heard called "fart boxes". Basically massively tuned for a resonant peak at some frequency like 45 hz or so.
There is a finite limit for how much efficiency you can have across a band with a given enclosure volume and loudspeaker parameters. By squashing the passband or introducing peaks you can get tremendously loud but it does ruin the sub for any musical application.
My knowledge is prosound and not car audio, but my "uneducated" guess is they can do this with 2 keys:
1. It's not a flat response box at all. Like it said, probably has a vicious peak at whatever frequency they're targeting. Looks like that was around 44 hz where I looked at the video.
2. These things tend to have huge linear excursion capability but low continuous power handling. Unlike prosound boxes which can get hammered on for hours, they only have to crank out SPL numbers in a short amount of time before the voice coil has a chance to cook, but that huge excursion means they can soak up a shitload of power and pump a huge displacement of air for a short while.
Those numbers aren't hard to hit in what I've heard called "fart boxes". Basically massively tuned for a resonant peak at some frequency like 45 hz or so.
There is a finite limit for how much efficiency you can have across a band with a given enclosure volume and loudspeaker parameters. By squashing the passband or introducing peaks you can get tremendously loud but it does ruin the sub for any musical application.
My knowledge is prosound and not car audio, but my "uneducated" guess is they can do this with 2 keys:
1. It's not a flat response box at all. Like it said, probably has a vicious peak at whatever frequency they're targeting. Looks like that was around 44 hz where I looked at the video.
2. These things tend to have huge linear excursion capability but low continuous power handling. Unlike prosound boxes which can get hammered on for hours, they only have to crank out SPL numbers in a short amount of time before the voice coil has a chance to cook, but that huge excursion means they can soak up a shitload of power and pump a huge displacement of air for a short while.
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What you are hearing in the video is the mic clipping. It simply can't record at that SPL. It would sound clean (enough) in person.
Fair point, although I want referring to what you hear from the microphone. I would imagine it has a fairly high level of distortion regardless, or at the least, not usable for any kind of music application. I'm no expert though!
It's certainly possible. At the very least at that spl the noise of everything else shaking and rattling would probably be a tremendous racket even at 20db down from the 44hz tone.
The subwoofer is probably already useless for any real musical appreciation because it likely has a horrific frequency response. You'd hear very little except for the one note it's very eager to produce.
The subwoofer is probably already useless for any real musical appreciation because it likely has a horrific frequency response. You'd hear very little except for the one note it's very eager to produce.
In hornresp I can get a 95db and a peak at around 45hz that gp up to 110dB... that's a lot of sound but you can't use this sub like you mention!
Ok, one more question: Why do car audio guys build these kind of box? I'm 16 almost 17 and I'm gonna build my first car soon! I want to put a decent sound system, I don'T wan to buy/ build something like this. how can we calculate the car resonant freq before making the box? to make sure that the sound is flat? I don't think these's 31 band EQ for car audio 😀
thanks
Ok, one more question: Why do car audio guys build these kind of box? I'm 16 almost 17 and I'm gonna build my first car soon! I want to put a decent sound system, I don'T wan to buy/ build something like this. how can we calculate the car resonant freq before making the box? to make sure that the sound is flat? I don't think these's 31 band EQ for car audio 😀
thanks
The good thing with cars are they tend to have no resonant frequency, due to no paralell walls.
What they do have are a lot of things that can shake(roof, doors, signs, hat shelves and so on) and destroy the musical experience. If you are very serious about the build(99% are not this serious) you can reduce these vibrations on the chassi with asphalt carpets(the rest are rather easy), then a car often tend to be one of the most favorable acoustical environments there is. You can make it very good in most cases without the asphalt carpets aswell
I've built a Bfm auto tuba, big box, 8" driver, very loud (130'ish in my small car would be my guess) and sounds really good. Never heard car sub as musical as that
What they do have are a lot of things that can shake(roof, doors, signs, hat shelves and so on) and destroy the musical experience. If you are very serious about the build(99% are not this serious) you can reduce these vibrations on the chassi with asphalt carpets(the rest are rather easy), then a car often tend to be one of the most favorable acoustical environments there is. You can make it very good in most cases without the asphalt carpets aswell
I've built a Bfm auto tuba, big box, 8" driver, very loud (130'ish in my small car would be my guess) and sounds really good. Never heard car sub as musical as that
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There's definitely an Fs and nowadays it's quite high: How to find your vehicle's resonant frequency for noobies 101 - SPL - SOUND PRESSURE LEVEL - SMD Forum
For SPL 'drag racing', you can get incredible gain/peak SPL by designing 'one note' BP alignments tuned to the vehicle's Fs.
GM
note, most SPL is generally produced at port tuning. At this frequency, there is minimal excursion, meaning the limiting factor is generally how much current the voice coil can handle, not the other way around.
"The good thing with cars are they tend to have no resonant frequency, due to no paralell walls."
So a Coke bottle has no resonance (~270hz)?
So a Coke bottle has no resonance (~270hz)?
Car audio SPL competition is a bit like drag racing - you design to hit a particular goal, but what you end up with is pretty useless for daily use.
Oh, and two good car audio 12" drivers in about 2.5~3 cu.ft. of space can easily clock over 140dB with enough power applied, and that design CAN be used for daily use - I've got one in my car 🙂. Cabin-gain does wonders...
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