I want a subwoofer flat from 10hz-40hz

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#61
Cloth Ears said:


I'd have to do a bit of research, but I thought that sub-hearing sounds at 125-130dB can have the same effect as someone slapping their hands over your ears - it can rupture the ear-drums. I'm not sure that it will deafen you, but will cause problems with your ears which can be the same thing.

From a quick scan, the following are the 'health' regulations:
Continuous dB Permissible Exposure Time
85 db 8 hours
88 dB 4 hours
91 db 2 hours
94 db 1 hour
97 db 30 minutes
100 db 15 minutes
103 db 7.5 minutes
106 dB 3.75 min (< 4min)
109 dB 1.875 min (< 2min)
112 dB .9375 min (~1 min)
115 dB .46875 min (~30 sec)

I remember the "Mythbusters" doing a show on low frequencies - surrounding one of them with a stack of subbies and pumping sounds from 8-80 Hz at volumes from 100dB to 160dB. They got the dude to wear ear proctection after the first test at 100dB.
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I'm sure those measurements are a-weighted ... unweighted (what we use to measure response) is a much higher reading in the "bass" area.

BassAwdyO said:
This thread is reducilis...

you dont want 130db@10hz... 110db@10hz gets scary. You will probably break something(although it may have nothing to do with your stereo). Perhaps your eardrums.... Although I dont believe infrasound is as damaging to the ears as some suggest.
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I've experienced over 150db at 10Hz, wasn't hard on the ears or the body at all, just kinda moves you around, no pain. But that 150db at 10Hz was bouncing ceiling tiles over 300ft away in that building, and opening and closing the glass doors well over 1000 ft away, it's unreal how far 10Hz travels.

This was in Mmats Room Of Doom, a bandpass with 16 of their mid level 15's powered by 4 of their 1kw amps tuned to 11Hz, playing 10Hz, port was large enough to walk into and stand in the front chamber. If more than 4 or 5 people was in it you could tell a big drop in the output. Last time I saw it was at the db drag world finials several years back.
 
#62
MrUnsocial said:






I've experienced over 150db at 10Hz, wasn't hard on the ears or the body at all, just kinda moves you around, no pain. But that 150db at 10Hz was bouncing ceiling tiles over 300ft away in that building, and opening and closing the glass doors well over 1000 ft away, it's unreal how far 10Hz travels.

This was in Mmats Room Of Doom, a bandpass with 16 of their mid level 15's powered by 4 of their 1kw amps tuned to 11Hz, playing 10Hz, port was large enough to walk into and stand in the front chamber. If more than 4 or 5 people was in it you could tell a big drop in the output. Last time I saw it was at the db drag world finials several years back.
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awesome I can't wait to bust out a window

the matience guy fixes them for $5 if you pay him on the side lol!
 
#64
How do you like baby's crying? Quite annoying huh? That's slightly less then 100dB, around 94~96dB. It's really "more than enough".
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Crying babies produce frequencies you're ears are most sensitive at, as your ears are optimised to hear the human voice. Outside that range the sensitivity of your ears drops both at higher and lower frequencies.

Because your ears are less sensitive in a frequency band they're also less vulnerable for damage by those frequencies. Vocals need about 10 dB less to get to the "painlimit" compared to subbass (130 dB is the given limit for subbas). The limit for infrasound could be even lower.

Even if WinISD Pro gives the f3 at 122 dB, it's still purely theoretical. Most high excursion woofers use rather small voicecoil diametres so powercompression will be relatively high, especially with loads of power. Also bare in mind that the number indicates the peaklevel and not the average, even if you play sines all the time.
So al together you should about double the number of things you need to get a true 122 dB in relation to the simulated needs.

Btw. Average disco's will produce peak SPL's over 125 dB for bass at 3 feet. Concert systems will do in great excess of that.

Good luck with your project tho you might want to learn about Hoffman's law.

Mvg Johan
 
#65
Rademakers said:
Crying babies produce frequencies you're ears are most sensitive at, as your ears are optimised to hear the human voice. Outside that range the sensitivity of your ears drops both at higher and lower frequencies.

Because your ears are less sensitive in a frequency band they're also less vulnerable for damage by those frequencies. Vocals need about 10 dB less to get to the "painlimit" compared to subbass (130 dB is the given limit for subbas). The limit for infrasound could be even lower.

Even if WinISD Pro gives the f3 at 122 dB, it's still purely theoretical. Most high excursion woofers use rather small voicecoil diametres so powercompression will be relatively high, especially with loads of power. Also bare in mind that the number indicates the peaklevel and not the average, even if you play sines all the time.
So al together you should about double the number of things you need to get a true 122 dB in relation to the simulated needs.

Btw. Average disco's will produce peak SPL's over 125 dB for bass at 3 feet. Concert systems will do in great excess of that.

Good luck with your project tho you might want to learn about Hoffman's law.

Mvg Johan
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true but given the wattage and box size they should reach max excursion or damn near close at that

I'm not looking for 20+hz at 130+ like a concert... this is easy... I could easily fit a 30hz horn

but it doesn't matter much because I already have midbasses that play that PERFECTLY

so I need something to mate with it with the same crazy SPL capabilities of the midbass... which happens to me 120 or so db at 40hz where they will be cut off

power compression will be high.... but the box is actually quite large and makes it more efficent

this isn't a simple task... and no normal person can fit 8 woofers in their home

I could imagine that 120db at 10hz can be reached in this room and sub setup with 2400 watts

the box may jump to 16-18 cubes if I can find sutiable PR's
 
#66
#67
A single PR for 4 drivers? Sorry it's not gonna work hehe!

Keep the windows closed, they will not rattle much at 10 Hz if they are well built, 10 Hz is a slow moving air mass. You'd lose all the SPL by opening them.

Anything larger than 15 cu.ft with 4 MKIII will work, but in WinISD Pro you'll see a peak at 10 Hz and that guy want flat FR.

You need to go ported to keep costs down if you go with 4 MKIII. If you still want to use passive radiators, then you'll need at least 2 of them because 2 drivers pairs are moving air. I'd need to simulate that.

Already purchased everything or what?
I hope that 14.5 cu.ft is internal net dimensions.
It'll weight around 150 lbs.
Against a wall you'll lose 3 dB so 119 dB at 10 Hz and 123 dB at 40 Hz. Might gain a dB or two because your room is smaller than the reference room curve gain I'm using so you'll probably achieve 120 dB at 10 Hz.

Good luck!
 
#68
simon5 said:
A single PR for 4 drivers? Sorry it's not gonna work hehe!

Keep the windows closed, they will not rattle much at 10 Hz if they are well built, 10 Hz is a slow moving air mass. You'd lose all the SPL by opening them.

Anything larger than 15 cu.ft with 4 MKIII will work, but in WinISD Pro you'll see a peak at 10 Hz and that guy want flat FR.

You need to go ported to keep costs down if you go with 4 MKIII. If you still want to use passive radiators, then you'll need at least 2 of them because 2 drivers pairs are moving air. I'd need to simulate that.

Already purchased everything or what?
I hope that 14.5 cu.ft is internal net dimensions.
It'll weight around 150 lbs.
Against a wall you'll lose 3 dB so 119 dB at 10 Hz and 123 dB at 40 Hz. Might gain a dB or two because your room is smaller than the reference room curve gain I'm using so you'll probably achieve 120 dB at 10 Hz.

Good luck!
Click to expand...


I'm buying them shortly

what about 2 18" PR's???

a single 18" PR is equvilent to 200 in^2 port.... big **** port man lol

this is of course internal.... PR's are a must here cause I can't figure out how to fit a 9 meter port in anything!! LOL
 
#69
ok the PR option is complicated... expensive and I can't figure out a way for it to look as good as the ported looks

thought I do like that 9hz bump it gives

but looking at it I think I can fit a port in 8" added to the depth... a port that's 22"x4".... a double layered port in this 50" long cabinet yields 100" or so that I can easily fit in the box without taking up that much volume inside... the port velocity at 2000w is around 14m/s peaks at 9hz... I would have to have a filter to keep it from overexcurting at 9.5hz.... so a nice 48db/octave LR at 9.5hz will do nicely 😀

I can make up the needed port by stuffing optimizing until I get the results I want ..... I know that you can add up to 50% length through stuffing to get the extra 45 inches needed...

anything wrong with this idea???

or should I continue on the PR route...

of course the port will be flared and the stuff will cut back on noise

if I need to go PR I will figure something out.... maybe 6 15" PR's... if I can find a suspension that can accept 2500+ grams
 
#70
I said you need to use more than one PR because you will exceed the PR max excursion near the tuning frequency. I'm going to home soon, I'll be able to simulate there. If you can wait 45 minutes I'll give you the results hehe!

If you want to go for big SPL don't stuff the port, you'll lose SPL.
 
#72
simon5 said:
I just checked and yes you'll need a bunch of PRs hehe, with an enclosure that large, you could easily put a bunch of flared ports instead I guess.

With PRs there's always overexcursion at 10 Hz or not enough SPL at 10 Hz...
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that's the problem I was running into as well

I need to just come up with a ported solution I guess... w/o stuffing
 
#74
Here is a sonosub I just built with a single Avalanche 18. 700 liters, 6'9" tall, 28" diameter tube, tuned to 14.75hz, with 600 available watts.

http://web.ics.purdue.edu/~scallas

I tested FR with the sub at least 8 feet away from the nearest wall with the meter 3 feet away from the driver - tested in 1hz increments at close to 95db is attached. Incorrect meter correction values account for the slight dip in the low end. Pink is raw, yellow is corrected.

Judging by this FR, WinISD and Unibox predictions are most likely correct. This means that with room gain, I can do over 120db flat down to 15hz, and get over 105db at 10hz. I have everything ready to go for the second one, but will probably wait for a house to assemble it.

You will never use 130db at 10hz because no material has a hot enough signal that low without driving your speakers at a similar level. So unless you listen at about 120db reference level, in which case you're deaf, you'll never get to use it. But I can understand and sympathize with your desire to go low and loud. No need to spend massive amounts of money or use tons of power. If you have a router, two of these and a capable amp will cost you $1300. I paid a little extra to get the MDF cnc routed.
 

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#77
Thanks, the Avalanche 18 can do some amazing things with the right enclosure. Aside from maybe a horn design, I doubt if any other single driver sub can match this in terms of spl and low frequency extension for anywhere near the cost. Once I assemble the second one, my bass capability will have no limits - assuming I don't watch movies at 120db like Audiophilenoob 🙂
 
#78
Cool thread. Good luck Audio.

I have been thinking about compound loading 2 15s or 2 18s in a sonotube such as Steve here did. Would I be able to cut the size down and still acheive impressive bottom end?

So, what would two of them there 15 inch AVs do in a say 14 inch tube appx 7.5 feet long. The woofers either facing each other in phaze or facing in the same direction yet wired out of phaze. Push pull design......would an arrangement such as this help our friend here get to 10 Hz?

C
 
#79
Throw the Winisd predictions out for these kind of SPLs in a room....

I think along your lines of bass levels and I'll tell you what I've come up with so far. I wanted something that was really flat and played low also.

I used a pair of the original Tumults and put them in 7ft3 boxes and tuned them at about 16Hz. Each one has a dedicated 2500wrms power amplifier, with thier own 30amp circuits. My room is around 15' x 12' with an 8' ceiling. At 20 Hz I could reach about 125db (on a Termlab) at my listening position with the amplifiers driven all the way into full clipping. At 20hz around 123db. At 16 Hz around 120db.

Let me tell you, it is pretty loud.

I am also looking into 4 18s soon as the Tumults no longer have enough output for me. I think it would be the way to go...

I never liked IB even in these situations, I've tried it, I don't like it.

Sealed is out of the question...

T-Lines get really long.....

LT? You gotta remeber the levels you want, only do the LT if you want to waste a bunch of money and power....

XXX? add some weight to it or tear out one of the spiders..... I have used them, they are beasts. Also, at 10Hz, your just more or less a big air-pump, pump the air, make bass.....

Go big, go ported, go with tons of power, tune low, use as many woofers as you can afford and don't look back....
 
#80
95Honda said:
Throw the Winisd predictions out for these kind of SPLs in a room....

I think along your lines of bass levels and I'll tell you what I've come up with so far. I wanted something that was really flat and played low also.

I used a pair of the original Tumults and put them in 7ft3 boxes and tuned them at about 16Hz. Each one has a dedicated 2500wrms power amplifier, with thier own 30amp circuits. My room is around 15' x 12' with an 8' ceiling. At 20 Hz I could reach about 125db (on a Termlab) at my listening position with the amplifiers driven all the way into full clipping. At 20hz around 123db. At 16 Hz around 120db.

Let me tell you, it is pretty loud.

I am also looking into 4 18s soon as the Tumults no longer have enough output for me. I think it would be the way to go...

I never liked IB even in these situations, I've tried it, I don't like it.

Sealed is out of the question...

T-Lines get really long.....

LT? You gotta remeber the levels you want, only do the LT if you want to waste a bunch of money and power....

XXX? add some weight to it or tear out one of the spiders..... I have used them, they are beasts. Also, at 10Hz, your just more or less a big air-pump, pump the air, make bass.....

Go big, go ported, go with tons of power, tune low, use as many woofers as you can afford and don't look back....
Click to expand...


🙂

thanks for the advice... the termlab is a far stiffer mic than WinISD would predict 😉

you must have some serious bass in there
 
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