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post #31 of 53 Old 03-04-2013, 10:48 AM
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Quote:
Originally Posted by Bill Fitzmaurice View Post

I don't know what that has to do with DIY, but in any event IB stands for 'infinite baffle'. All sealed subs are infinite baffle.

I'm talking about the kinds of things you'd see at the "cult of the infinitely baffled". If there's another term for those sorts of designs based on manifolds built into the structures of walls and such I'd be interested in hearing it. I'm not really terribly conversant with speaker design and assumed that what they called those things was correct.

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post #32 of 53 Old 03-04-2013, 10:52 AM
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The effectiveness of isolation aside, every sub I have owned (20 or so) including Velo DD18’s. JL Audio Fathoms and Danley Tapped Horns all had cabinets that shook/vibrated when producing reference level bass. I guess these were all just poorly engineered designs. I could throw many other subs into that group and the only subs that I have experienced that had minimal cabinet vibration (still had some) were the Seaton Submersive’s (dual opposed).

As to the DIY comment ... it wasn't insulting, just amusing ... smile.gif

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post #33 of 53 Old 03-04-2013, 11:41 AM
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Quote:
Originally Posted by RMK! View Post

The effectiveness of isolation aside, every sub I have owned (20 or so) including Velo DD18’s. JL Audio Fathoms and Danley Tapped Horns all had cabinets that shook/vibrated when producing reference level bass. I guess these were all just poorly engineered designs. I could throw many other subs into that group and the only subs that I have experienced that had minimal cabinet vibration (still had some) were the Seaton Submersive’s (dual opposed).

As to the DIY comment ... it wasn't insulting, just amusing ... smile.gif
If you play a sub loud enough you get to witness Newton's Third Law of Motion in action, as the sub starts to dance. That has absolutely nothing to do with the panels flexing. The Seatons don't because they're dual opposed, so the cone motion of one driver that would otherwise cause the cab to move in the opposite direction of the cone movement is countered by the equal opposite movement of the second cone.
And not to be insulting again, but how many subs you've owned has no bearing on your level of expertise. How many you've designed would. I've owned a dozen cars over the years, that doesn't make me an automotive engineer.

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post #34 of 53 Old 03-04-2013, 11:54 AM
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Quote:
Originally Posted by JD in NJ View Post

I'm talking about the kinds of things you'd see at the "cult of the infinitely baffled". If there's another term for those sorts of designs based on manifolds built into the structures of walls and such I'd be interested in hearing it. I'm not really terribly conversant with speaker design and assumed that what they called those things was correct.

Infinite baffle:
noun, Audio.
A loudspeaker enclosure that totally separates sound emanating from the rear of the speaker cone from sound emanating in front, so as to prevent mutual interference.


That's the case with a 1/2 cu ft sealed box, and it's the case with a driver mounted in a ceiling, floor or wall. When guys started mounting drivers that way they called them, correctly, infinite baffles. But then they started, incorrectly, stating that infinite baffle referred only to drivers mounted in that fashion. That's probably because few of them, or for that matter their fathers, were even born when the term was defined back in the 1930s.

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post #35 of 53 Old 03-04-2013, 12:05 PM
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Quote:
Originally Posted by Bill Fitzmaurice View Post


Infinite baffle:
noun, Audio.
A loudspeaker enclosure that totally separates sound emanating from the rear of the speaker cone from sound emanating in front, so as to prevent mutual interference.


That's the case with a 1/2 cu ft sealed box, and it's the case with a driver mounted in a ceiling, floor or wall. When guys started mounting drivers that way they called them, correctly, infinite baffles. But then they started, incorrectly, stating that infinite baffle referred only to drivers mounted in that fashion. That's probably because few of them, or for that matter their fathers, were even born when the term was defined back in the 1930s.

Thanks for that. I do appreciate actual deep knowledge of a subject, whether I possess it or not.

Sadly, now I don't know how I would word my post from earlier without excessive verbiage.

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post #36 of 53 Old 03-04-2013, 12:13 PM
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Quote:
Originally Posted by Bill Fitzmaurice View Post

If you play a sub loud enough you get to witness Newton's Third Law of Motion in action, as the sub starts to dance. That has absolutely nothing to do with the panels flexing. The Seatons don't because they're dual opposed, so the cone motion of one driver that would otherwise cause the cab to move in the opposite direction of the cone movement is countered by the equal opposite movement of the second cone.
And not to be insulting again, but how many subs you've owned has no bearing on your level of expertise. How many you've designed would. I've owned a dozen cars over the years, that doesn't make me an automotive engineer.

Thank you professor rolleyes.gif, I mentioned the number of subs I've owned as validation of a direct experience, not as a claim of any particular expertise and, I mentioned nothing about "panels flexing". smile.gif

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post #37 of 53 Old 03-04-2013, 01:27 PM
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Thanks BeeMan your right the rockwool is 4"thick so I also thought about putting the rockwool between the mdf and quiterock and add ati vibration rubber feet that are 4×4×2" thick
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post #38 of 53 Old 03-04-2013, 02:03 PM
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Quote:
Originally Posted by RMK! View Post

I mentioned nothing about "panels flexing". smile.gif
Perhaps not, but for subs to transfer energy to the floor the way Auralex and the like claim they would have to. As for being a professor, I've had offers, but that would mean moving to State College PA. or Hartford, and I'm not interested. I already make as much as a tenured professor anyway, and I don't have to go leave my house to do it.

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post #39 of 53 Old 03-04-2013, 02:41 PM
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Originally Posted by 5seonds View Post

Build your own. that's what I did, and they were cheap ($15 ea?), easy (2 hours ea?), and matches the subs and my room (Exactly the same dimensions as the sub, and the carpet is leftover from the installation).







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post #40 of 53 Old 03-04-2013, 02:45 PM
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That simple huh it looks good im gonna do the same with a bunch of materials I got left over from my studio build but the subs weigh 97lbs
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post #41 of 53 Old 03-04-2013, 02:57 PM
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Quote:
Originally Posted by Bill Fitzmaurice View Post

Perhaps not, but for subs to transfer energy to the floor the way Auralex and the like claim they would have to. As for being a professor, I've had offers, but that would mean moving to State College PA. or Hartford, and I'm not interested. I already make as much as a tenured professor anyway, and I don't have to go leave my house to do it.

Humm, without a Ph.D most institutions only pay the Prof's $70-80K. Not chump change but hardly bragging rights. The only way to make more is to be good at begging (i.e. writing for Grants).

Not being from academia myself I know this cause I live with someone working on her Ph.D. She has no desire to teach as she would have to take a huge pay cut. OTOH, she is excellent at begging and may turn to teaching later in life ...

How did we get on this subject ... tongue.gif

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post #42 of 53 Old 03-04-2013, 03:28 PM
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Fore-aft rocking of a subwoofer enclosure from the driver motion can certainly be transferred to a suspended floor vs. say a concrete slab foundation on grade or a basement. This is entirely separate from panel flexing, which bracing can easily reduce to insignificant levels. Depending on the driver and the weight of the box, the rocking forces can be quite significant. This is where some form of feet or spikes are needed to first eliminate noises on a hard floor or obvious movement on a carpeted floor. If that energy happens to be mechanically coupling to the floor, it can be perceived or even heard. This is the situation where some form of isolation can be of help, or you can use an inert design with opposing / force cancelling configuration. That doesn't mean that all devices out there are appropriate or as effective as they might suggest, but it can be an issue, and some can make a readily perceptible difference.

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post #43 of 53 Old 03-04-2013, 04:19 PM
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Quote:
Originally Posted by Mark Seaton View Post

Fore-aft rocking of a subwoofer enclosure from the driver motion can certainly be transferred to a suspended floor vs. say a concrete slab foundation on grade or a basement. This is entirely separate from panel flexing, which bracing can easily reduce to insignificant levels. Depending on the driver and the weight of the box, the rocking forces can be quite significant. This is where some form of feet or spikes are needed to first eliminate noises on a hard floor or obvious movement on a carpeted floor. If that energy happens to be mechanically coupling to the floor, it can be perceived or even heard. This is the situation where some form of isolation can be of help, or you can use an inert design with opposing / force cancelling configuration. That doesn't mean that all devices out there are appropriate or as effective as they might suggest, but it can be an issue, and some can make a readily perceptible difference.

Yea, what he said. wink.gif

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Thanks BeeMan...

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post #45 of 53 Old 03-04-2013, 04:49 PM
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Quote:
Originally Posted by Mark Seaton View Post

Fore-aft rocking of a subwoofer enclosure from the driver motion can certainly be transferred to a suspended floor vs. say a concrete slab foundation on grade or a basement. This is entirely separate from panel flexing, which bracing can easily reduce to insignificant levels. Depending on the driver and the weight of the box, the rocking forces can be quite significant. This is where some form of feet or spikes are needed to first eliminate noises on a hard floor or obvious movement on a carpeted floor. If that energy happens to be mechanically coupling to the floor, it can be perceived or even heard. This is the situation where some form of isolation can be of help, or you can use an inert design with opposing / force cancelling configuration. That doesn't mean that all devices out there are appropriate or as effective as they might suggest, but it can be an issue, and some can make a readily perceptible difference.
+1. Of course, you don't need a $50 or more device to do the job. Rubber feet are usually adequate. These, cut to size, work extremely well on bare wood or tile floors, and you can't see them:
http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=202015909&R=202015909#.UP66YGeYUYc

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post #46 of 53 Old 03-04-2013, 05:13 PM
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Quote:
Originally Posted by Bill Fitzmaurice View Post

+1. Of course, you don't need a $50 or more device to do the job. Rubber feet are usually adequate. These, cut to size, work extremely well on bare wood or tile floors, and you can't see them:
http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=202015909&R=202015909#.UP66YGeYUYc


I just ordered a Rythmik LV12R. According to the specs the shipping weight is 69lbs - which seems pretty heavy.

I am worried that due to the extra weight, overtime it might squish down a pad like that, thereby defeating some of the vibration absorbtion effect.

These little things are pretty cheap:
http://www.amazon.com/Mason-Neoprene-Sandwich-Vibration-Isolation/dp/B006W0PCTG/ref=pd_sim_sbs_indust_4

I was thinking that if I put one of them under each of the LV12R's feet, it might help to distribute the weight a bit more, and give it a little absorbtion to boot. Do you think this would help at all?




EDIT:

I meant put one of those little blocks under each of the sub's feet and put it on a pad like the one you linked.
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post #47 of 53 Old 03-04-2013, 05:21 PM
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Also, I am new to this so I do not know much yet, but I am interested in learning and understanding the reasons behind doing an action, rather than just obtaining the end result of it.

With that said, am I understanding this correctly?

The purpose of these pads/risers/subdude/etc. are two fold: 1) to help absorb the transfer of vibrations due to the direct contact between the subwoofer and the floor; and 2) help by simply being a sound dampening mat on a hard surface (like hardwood floor) similar to how just a piece of carpet would be.







(oh and as for the post above, I forgot to mention I have an old hardwood floor in my living room. It flexes and creaks when I walk across it. I live in an apt so I cannot really do much about it. I was not sure if this would make a difference in the response.)
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post #48 of 53 Old 03-04-2013, 05:30 PM
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Originally Posted by Bill Fitzmaurice View Post

+1. Of course, you don't need a $50 or more device to do the job. Rubber feet are usually adequate. These, cut to size, work extremely well on bare wood or tile floors, and you can't see them:
http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=202015909&R=202015909#.UP66YGeYUYc
Something like that is exactly what I was looking for when you were recommending the blue sleeping pad. tongue.gif Much better.

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post #49 of 53 Old 03-04-2013, 07:28 PM
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Originally Posted by Goride View Post

With that said, am I understanding this correctly?

The purpose of these pads/risers/subdude/etc. are two fold: 1) to help absorb the transfer of vibrations due to the direct contact between the subwoofer and the floor;
That's the claim. But any vibrations transferred between the sub and floor are in the midrange, not the sub bass. The maximum extent that a panel could flex is a few hundreths of a millimeter. It doesn't take a whole lot of material to prevent that amount of panel flex from vibrating the floor. Carpet alone is adequate. If you don't have a carpet rubber feet are probably sufficient, but if not one of the pads I posted the link to is all you need.

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post #50 of 53 Old 03-05-2013, 04:08 AM
 
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Being an evil person, our subs have been placed directly on a bare hardwood floor in what would be accurately characterized as a "live" room; lots of echos/reverberations. The subs are raised off the floor by an inch, raised on manufacture provided, little tapered legs.

My opinion, more than simple legs to raise the sub off the floor, the trick is to take the time to carefully and "ACCURATELY" integrate one's sub into a room's acoustics. And by accurate, that means, without emotional attachment. In my opinion, boomy subs is a sign of someone's subs being driven too hot for a room's acoustics and if this is the case, is responsible for much of the shake, rattle and roll that many here are asking about.

If one doesn't have a room analyzing program and their subwoofer system is guilty of being over driven or is poorly integrated into their room's acoustics, they'll never know the why of it all. Just saying.
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post #51 of 53 Old 03-05-2013, 06:42 AM
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Quote:
Originally Posted by Goride View Post

The purpose of these pads/risers/subdude/etc. are two fold: 1) to help absorb the transfer of vibrations due to the direct contact between the subwoofer and the floor; and 2) help by simply being a sound dampening mat on a hard surface (like hardwood floor) similar to how just a piece of carpet would be.

1) For the most part, yes; they de-couple the sub from the floor, so the transmitted vibrations are minimized.

2) A piece of carpet doesn't really perform as well because it won't provide the same degree of isolation as some of the acoustic foam does.

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post #52 of 53 Old 03-05-2013, 09:27 AM
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Quote:
Originally Posted by Goride View Post

Quote:
Originally Posted by Bill Fitzmaurice View Post

+1. Of course, you don't need a $50 or more device to do the job. Rubber feet are usually adequate. These, cut to size, work extremely well on bare wood or tile floors, and you can't see them:
http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=202015909&R=202015909#.UP66YGeYUYc


I just ordered a Rythmik LV12R. According to the specs the shipping weight is 69lbs - which seems pretty heavy.

I am worried that due to the extra weight, overtime it might squish down a pad like that, thereby defeating some of the vibration absorbtion effect.

These little things are pretty cheap:
http://www.amazon.com/Mason-Neoprene-Sandwich-Vibration-Isolation/dp/B006W0PCTG/ref=pd_sim_sbs_indust_4

I was thinking that if I put one of them under each of the LV12R's feet, it might help to distribute the weight a bit more, and give it a little absorbtion to boot. Do you think this would help at all?

EDIT:

I meant put one of those little blocks under each of the sub's feet and put it on a pad like the one you linked.

In relative terms, your Rythmik is not very heavy. Furthermore, if you want to have actual isolation with soft, compliant materials, you actually need the "squish" you refer to. If you have materials rated for multiples the weight, they won't compress and won't have any spring/compliance to them. Weight for materials is a matter of weight per square area, usually per inch. So a pad 2x the square dimension can support 4x the weight. The pads you link to are probably a little too heavy duty for the use, and really aren't needed.

While a little trickier to figure out what is what online unless you know the material or trade names of items rather than brand names, McMaster offers most any such material you would need.

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post #53 of 53 Old 03-05-2013, 10:37 AM
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The studio we built is for live band rehearsals and it is in a office building on the top floor so we do wanna be mindful of our surroundings my brother wanted 3 18" subs I said overkill so we agreed on 2 15" subs. We built a drummer isolation riser with a plexiglass shield the riser is 4"×7L×8W so I told him I would buy 3 Gamma iso riser 1 for the bass amp and 2 for the subs but money ran out so I'm gonna build them myself. But I just didn't no how to go about it look on youtube and found nothing but seeing the pic 5seconds posted got my wheels turning so when im done with all three ill post the picks of them and the best thing is its I don't have to spend a dime :-)
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