My subs are gonna wreck my house! (1 Viewer)

[Harry Lincoln]

About two months ago I finished building two Shiva sonosubs tuned to 16.5 hz in 170lt (6ft^3) cabinets. They are currenly powered by the internal amps from two Yamaha YST-sw300 subs 185w 4ohms. My room is quite small - 2.7m x 3m x 3.5m (1m = 3.3 feet I think) with no openings.

I was running some SPL tests the other night using the TPM dvd and some sine waves, with no speakers connected, only the subs. I set the subs to approx 10db hot and played the THX intro repeatedly, increasing the volume each time. I stopped at full ref level on the amp (subs 10db over ref) because I thought I was going to damage the house. At this level the needle on the rat shak meter goes off the scale on the 120db range (126db+ the meter correction)on the exploding sphere at the listening position, I got down on the floor with a torch and watched the drivers at this level, the X-MAX is 32mm I think, they didnt appear to be going close to this.

There is a large window 1.5m x 1.5m on the wall behind the subs, when doing the tests the window was vibrating so bad I was suprised it didn't break. There is also a crack the whole way around the outer edge of the ceiling along the cornices due to the subs. I want to push these things harder but I'm a bit worried about the window, is there anything I can do to strengthen it while I do the test again?

I have read that some people measure peaks in the 130 - 145db range, what are they using to measure this? - the rat shak meter only goes up to 126db uncorrected.

The amount of good clean bass I can get from these things is bullshit! I cant imagine what some of those 140db + subs would be like.

Harry.

 

[Pat K]

LOL. .this post is funny.. Hmmm... Maybe put some plexiglass over it, or just take out the window, and change it for plexiglass, then brace it better. I dunno man.

 

[Jeff_Krueger]

Well you could always do as the DB dragers do, replace your windows with 2" thick bullet proof glass
But honestly, maybe making sure the window is securely mounted in the frame and the frame itself is screwed tightly to the wall and shimed properly. Also maybe checking/replacing the weather stripping to damp vibrations from the window in the frame. That's all I can think of, I doubt you would have to worry about the glass breaking just from the SPL only maybe from the window being loose and rattling in the frame. Good luck

 

[Greg Monfort]

>My room is quite small - 2.7m x 3m x 3.5m (1m = 3.3 feet I think) with no openings.

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Yes, a tiny room for this sub combo.

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>I got down on the floor with a torch and watched the drivers at this level, the X-MAX is 32mm I think, they didnt appear to be going close to this.

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That's ~peak-to-peak.

Probably not. You're already getting significant room gain at modest power.

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>I want to push these things harder but I'm a bit worried about the window, is there anything I can do to strengthen

it while I do the test again?

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Describe the window construction, IOW is it a big one piece picture window or?

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I have read that some people measure peaks in the 130 - 145db range, what are they using to measure this? - the rat shak meter only goes up to 126db uncorrected.

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There are special mics that go up to 200+dB, but are very expensive, and for obvious reasons aren't hand held esigns. Regardless, while there's a few folks around the world with sub systems this powerful, they're main goal is to be able to reproduce music at 'live' SPLs with vanishingly low distortion, so basically only use a fraction of their potential.

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>The amount of good clean bass I can get from these things is bullshit!

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Why is it BS? Do they really sound that distorted at this relatively low power, or are you clipping the amp?

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> I cant imagine what some of those 140db + subs would be like.

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Due to the human hearing curve, they don't 'sound' much louder, just a bit more pressurized feeling as your ear drums are already flattened. Now if you exposed yourself to this much SPL higher up in the BW for even a short period, then your hearing would be ~ instantly damaged.

GM

 

[Garrett Lundy]

So umm... Unless you remove the window anyway, how are you going to escape your room "with no openings"?!?!
Seriously though, I hope you never try to play a WolfPac cd through that system...Your skull might cave-in

 

[Harry Lincoln]

quote
>The amount of good clean bass I can get from these things is bullshit!
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Why is it BS? Do they really sound that distorted at this relatively low power, or are you clipping the amp?
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Greg, I think you misunderstood me, there is no distortion or clipping in the subs, what I mean is I am totally blown away by the performance of the sonosubs, I thought my previous setup of two Yammy YST-SW300 was good(I was wrong), until I heard these things! I am suprised that I can push them so hard with no signs of distortion or bottoming.
>I got down on the floor with a torch and watched the drivers at this level, the X-MAX is 32mm I think, they didnt appear to be going close to this.
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That's ~peak-to-peak.
Yes, 32mm peak to peak, it looked like about 6-8mm(roughly) short of this to my eye.
The window structure consists of 4 smaller windows and the one big one in the middle, I think it is moving in the wooden frame, I dont want to pull the window out or anything as I am renting a room of a friend (I do all SPL tests when he's not home )just wondered if there's an easy way to reinforce it?
Seriously though, I hope you never try to play a WolfPac cd through that system...Your skull might cave-in
Garret, never heard of that CD but I like the idea of having my skull crushed , where can I find ore info?
Harry.

 

[Greg Monfort]

>Greg, I think you misunderstood me, there is no distortion or clipping in the subs, what I mean is I am totally blown away by the performance of the sonosubs, I thought my previous setup of two Yammy YST-SW300 was good(I was wrong), until I heard these things!
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Ok, here in the USA BS normally means something obviously not true, such as saying a $10 clock radio has a 20-20kHz flat frequency response.
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> I am suprised that I can push them so hard with no signs of distortion or bottoming.
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High linear excursion and some room gain is a beautiful thing.
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>The window structure consists of 4 smaller windows and the one big one in the middle, I think it is moving in the wooden frame, I dont want to pull the window out or anything as I am renting a room of a friend
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Since it can't be permanent, get some doorjamb shims and cut them as required to wedge them to take out the tolerances. For the large windowpane, you can velcro a MDF plate to cover it. This will mass load the window a bit and the slight air gap will help too.
Only place the velcro around the perimeter with room to get your fingers around the edges as it's a bear to pull apart long seams, and if you run a seam down the middle or diagonally, you might pop the glass. If the WP is really large, add a diagonal stiffener to the MDF plate to keep it from resonating.
If you want to see what they can really do, then get a pipe organ CD that includes a 16Hz (32ft) pipe, such as Eduardo Mata, Dallas Symphony Orchestra (Dorian, Dor-90200) or Jahja Ling, Royal Philharmonic Orchestra, (Telarc, CD-80136). Be careful with the volume control though as you don't have much power and excursion increases 4x/octave, so it gets used up real fast at 16Hz.
GM

 

[Bryan Michael]

open a window easy and simple

 

[Harry Lincoln]

Thanks Greg, I'll give that a try on the window. Might have to check out the pipe organ CD too.
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Ok, here in the USA BS normally means something obviously not true, such as saying a $10 clock radio has a 20-20kHz flat frequency response.
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Dont Bose make a clock radio that meets those specs?
Harry.

 

[Scott Simonian]

OMG we are sooo mean.