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Barefaced IsoTilt wedges


funky8884
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[quote name='funky8884' timestamp='1350806949' post='1843572']
In one of my emails to Alex asking about a Barefaced Cab solution he mentioned an ''IsoTilt wedge''.
Has anyone out there got one / used one ?
[/quote]

Alex told me he needed to get to see a supplier for the foam I think, anyway, they aren't available as yet. Auralex GRAMMA is your best bet.

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[quote name='Happy Jack' timestamp='1350906480' post='1844821']
Barefaced is so what?
[/quote]
It's an 'acoustic seperation' stand that allows the cab to be tilted and still have your amp on top. So, in small venues the sound it thrown at the back of your head instead of your knees and you can hear yourself better.

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If its just tilting the cab back a bit for a better angle, why do you need a super duper acoustic thingymajiggy?
I have used a Travis Perkins[sup]TM[/sup] Offcut[sup]TM[/sup] Doorstop[sup]TM[/sup] positioned under the front of the cab to tilt mine back in the past, the further you push it under the greater the angle (yes its even adjustable) and you can order them direct from me for only £10.99!! +P&P
or you can make your own out of anything you like :)

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It's not just a tilt back device, it isolates the cab from the floor, which is a good thing on hollow boomy stages and helps you sound remain your sound in bad acoustic conditions, check out the Auralex GRAMMA pad, not a tilt device just a de-coupler, Alex's plan is to provide the de-coupleing effect with a handy tilt-back.

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[quote name='WinterMute' timestamp='1350982351' post='1845727']
It's not just a tilt back device, it isolates the cab from the floor, which is a good thing on hollow boomy stages and helps you sound remain your sound in bad acoustic conditions, check out the Auralex GRAMMA pad, not a tilt device just a de-coupler, Alex's plan is to provide the de-coupleing effect with a handy tilt-back.
[/quote]

I'm familiar with the gramma pad and the many many threads there have been discussing the effectiveness of what seems like a hilariously overpriced bit of wood and foam to me.

I thought part of the whole point about having the bass cab on the floor was to [i]allow[/i] it to couple, increasing the LF response. I mentioned raising my cab off the floor in another post and was warned about the de-coupling that might occur and how detrimental it [i]could[/i] be to my sound! In the end, it depends on the application.

Hey I'm sure there are situations that suit raised, tilted, both or neither. I just think some of these 'axecessories' are a bit overpriced, and over-engineered. Having not seen the Barefaced Iso wedge I cannot comment on that, but in terms of solving the 'problem' there are many ways to build a bridge...

I've ordered an amp stand recently, it wasn't expensive (about £25). The angle is adjustable, as is the height, and it folds away nice and flat. It decouples the speaker from the floor and raises the cab to a height where it is in line with my ears. happy days.

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[quote name='brensabre79' timestamp='1350983687' post='1845742']
I'm familiar with the gramma pad and the many many threads there have been discussing the effectiveness of what seems like a hilariously overpriced bit of wood and foam to me.

I thought part of the whole point about having the bass cab on the floor was to [i]allow[/i] it to couple, increasing the LF response. I mentioned raising my cab off the floor in another post and was warned about the de-coupling that might occur and how detrimental it [i]could[/i] be to my sound! In the end, it depends on the application.
[/quote]

As I understand it from knowledgeable types, there are two types of coupling. The mechanical sort from having your cab on the floor, which gives the nasty boom, and boundary reinforcement, which is about how the waves reflect off the floor and interact. That one you need and can lose if you raise the cab too much.

Agree that the Gramma pad is expensive, but auralex strips are cheap enough and definitely solve the boominess problem.

Edited by fatback
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[quote name='brensabre79' timestamp='1350983687' post='1845742']I thought part of the whole point about having the bass cab on the floor was to [i]allow[/i] it to couple, increasing the LF response. I mentioned raising my cab off the floor in another post and was warned about the de-coupling that might occur and how detrimental it [i]could[/i] be to my sound! In the end, it depends on the application.[/quote]

As I said in that thread, but it seems to be quite hard to explain clearly, there are two sorts of coupling. One is mechanical coupling which is through physical contact with the floor causing the floor to vibrate - this is almost always BAD. The only exception is when you're playing a double bass with no amp and need more output. The other is acoustic coupling, where the floor reflects the downwards output (the lower hemisphere of sound coming from your cab) so it joins up with the upwards output and thus increases the useful output at low frequencies. The IsoTilt wedges will minimise mechanical coupling without losing your acoustic coupling, and increase the mid/treble audibility on small stages. Ordered the first ones from the foam people last Friday (almost exactly a year after the project ended up in limbo due to the cost of prototyping)...

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I guess the lack of boundary reinforcement is akin to playing an outdoor gig where there's no reflective surfaces (apart from the stage).
It does make me wonder however, as I've been in more than a few 'acoustically designed' studio control rooms in my time, all of which have the monitor speakers positioned either at head height or above. Where a sub woofer has been used this has usually been shoved in a corner on the floor, or under the desk, but generally the midfield and nearfield monitors have been substantial enough not to require a sub. The bass, as well as all other sounds, come out of these speakers and everything was usually tight and focused, and of course there was plenty of bass in the mix.

We used to take our mixes straight to the local nightclubs (back when I was making dance music for a living) and get the DJ to stick it in their set (they were usually delighted to be the first one to play it, straight from the mixdown that night). It was always there that we would discover unpleasant resonances in the bass that we hadn't heard before, particular to that room (they would be different resonances in different places) - where they had a line of bass bins on the floor...

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[quote name='alexclaber' timestamp='1350993041' post='1845905']
As I said in that thread, but it seems to be quite hard to explain clearly, there are two sorts of coupling. One is mechanical coupling which is through physical contact with the floor causing the floor to vibrate - this is almost always BAD. The only exception is when you're playing a double bass with no amp and need more output. The other is acoustic coupling, where the floor reflects the downwards output (the lower hemisphere of sound coming from your cab) so it joins up with the upwards output and thus increases the useful output at low frequencies.The IsoTilt wedges will minimise mechanical coupling without losing your acoustic coupling, and increase the mid/treble audibility on small stages. Ordered the first ones from the foam people last Friday (almost exactly a year after the project ended up in limbo due to the cost of prototyping)...
[/quote]

Thanks Alex, you did explain well. I was just wondering what the difference between raising the cab off the floor on a stand vs on a Gramma pad (or equivalent) would actually be in the real world? And also, this is an entirely different subject to simply tilting the cab backwards (for which a doorstop will be adequate, but will not reduce mechanical coupling..?) so that its pointing at your head.

Sorry if I'm coming across as argumentative, or just not getting it. I appreciate your IsoTilt will offer both tilting and decoupling (mechanical), and I'm certainly not trying to belittle your product without a) seeing it and B) understanding how it works! I imagine if you want both angle adjustment and mechanical coupling reduction your product will probably be an infinitely more eloquent solution than a block of acoustic foam with a wedge underneath it.

I guess I'm asking how is it going to be different to a stand (or a beer crate etc.) in terms of a solution to the problem?

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[quote name='brensabre79' timestamp='1350993932' post='1845926']
I guess I'm asking how is it going to be different to a stand (or a beer crate etc.) in terms of a solution to the problem?
[/quote]

Because foam is a better mechanical decoupler than a solid stand. Having said that, I've used offcuts of fairly stiff packing foam under monitor speakers etc for years and they work just as well as 'acoustic' foam in this application.

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Point of fact: Unless the cab is defectively constructed there's no such thing as mechanical coupling. That phenomenon can only occur if the cab walls flex, and the walls of good cabs don't flex. Even relatively flimsy cabs don't vibrate in the lows, they vibrate in the mids. If they vibrated in the lows they'd be unusable. All low frequency vibration of the floor is caused by the acoustic output of the cab. Therefore so-called isolation devices have absolutely no effect on floor or other room surface vibrations.

However, if the floor is vibrating said vibrations can then be transferred back to the cab, and the head atop it, and stopping those vibrations can be worthwhile. But doing so doesn't require a high level of sophistication, let alone high cost. A bit of carpet will do the trick.

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I've never seen much sense in buying a lightweight rig and then carting an amp stand around with you. Foam is one of those things that actually costs far more than you'd think it should (hence the prototyping issue) so the IsoTilts may seem expensive for some bits of foam but conversely they do what an amp stand does with much less weight and you can chuck them in your gigbag with your bass.

I was sceptical of cabs physically transferring vibrations to the floor directly but as bits of foam make a difference then something is clearly happening! Maybe what actually happens is that the cab is acoustically exciting the floor but by raising the cab on some suitable foam you damp the vibrations, as you now have a damped mass on the vibrating membrane - like the difference between fretting a string and muting a string?

Edited by alexclaber
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[quote name='alexclaber' timestamp='1350996617' post='1845973']
I was sceptical of cabs physically transferring vibrations to the floor directly but as bits of foam make a difference then something is clearly happening! Maybe what actually happens is that the cab is acoustically exciting the floor but by raising the cab on some suitable foam you damp the vibrations, as you now have a damped mass on the vibrating membrane - like the difference between fretting a string and muting a string?
[/quote]It's closer to the difference between playing your bass with its body touching or not touching the cab. If the floor is vibrating and those vibrations are being transferred to the cab you've set up a feedback loop. Since the cone is isolated from the cabinet by the driver suspension the effect of the feedback loop isn't severe, but it's there.

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[quote name='Bill Fitzmaurice' timestamp='1350996408' post='1845970']
Point of fact: Unless the cab is defectively constructed there's no such thing as mechanical coupling. That phenomenon can only occur if the cab walls flex
[/quote]

With all due respect, that's not correct. A diamond stylus is extremely rigid and makes a great mechanical coupler. Mechanical force can either be transferred, or converted e.g. to heat. With a rigid body it is being transferred, to the floor in this case.

[quote name='Bill Fitzmaurice' timestamp='1350998366' post='1846002']
Since the cone is isolated from the cabinet by the driver suspension the effect of the feedback loop isn't severe, but it's there.
[/quote]

The force is generated in the motor. That includes the magnet, which is rigidly attached to the cab. Newton's third law - the force transmits into the cab as well as the cone.

Efficient transfer of energy by a lightweight but rigid cab (without damping) will give greater vibration transfer to a resonant body like the floor. Mass greatly increases the force required to produce a noticeable reaction. This is secondary school physics in action!

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[quote name='Bill Fitzmaurice' timestamp='1350996408' post='1845970']
Point of fact: Unless the cab is defectively constructed there's no such thing as mechanical coupling. That phenomenon can only occur if the cab walls flex, and the walls of good cabs don't flex. Even relatively flimsy cabs don't vibrate in the lows, they vibrate in the mids. If they vibrated in the lows they'd be unusable. All low frequency vibration of the floor is caused by the acoustic output of the cab. Therefore so-called isolation devices have absolutely no effect on floor or other room surface vibrations.

However, if the floor is vibrating said vibrations can then be transferred back to the cab, and the head atop it, and stopping those vibrations can be worthwhile. But doing so doesn't require a high level of sophistication, let alone high cost. A bit of carpet will do the trick.
[/quote]


I (and I believe Sir Isaac Newton) disagree.

Irrespective of the stiffness of the cabinet or whether the sides are vibrating, Newton's laws/conservation of momentum means that if you are moving the speaker cone forward then the rest of the cabinet will to move backwards by an amount inversely proportional to their relative weight of the two parts (i.e. the cone/coil and the rest of the cabinet), so that the net momentum change is zero. This would occur even if it were in a vacuum.

On top of this is the fact that you are pushing air with the cone and the equal but opposite force again feeds back into the cabinet. - even if the cabinet is completely stiff.

These forces and any consequent movement will be transferred into the supporting mechanism whether that is the floor or the isolating pad.

How significant these are I have no idea, but they will be there.

Edited by Count Bassy
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[quote name='LawrenceH' timestamp='1351006496' post='1846113']
Efficient transfer of energy by a lightweight but rigid cab (without damping) will give greater vibration transfer to a resonant body like the floor. Mass greatly increases the force required to produce a noticeable reaction. This is secondary school physics in action!
[/quote]One does not need a post graduate degree to know that if over 95% of the energy being output by the speaker is acoustical, not mechanical, then isolating that 5% is not going to stop the floor from vibrating, nor will the reduction accomplished have an audible result. But at the least one needs to have taken undergraduate courses in acousttcal engineering to know that over 95% of the output of a speaker is acoustical, not mechanical. The schlockmeisters who claim that their products will prevent a speaker from causing the floor to vibrate are well aware that the vast majority of consumers have no formal education in acoustical engineering, and that being the case many of them will accept their advertised claims at face value. At least enough of them to keep them in business. Alex at present doesn't fall into this category, having only stated so far that isolation does have an effect, but not the effect that Auralex for one erroneously claims.

[quote]I (and I believe Sir Isaac Newton) disagree

Irrespective of the stiffness of the cabinet or whether the sides are vibrating, Newton's laws/conservation of momentum means that if you are moving the speaker cone forward then the rest of the cabinet will to move backwards by an amount inversely proportional to their relative weight of the two parts (i.e. the cone/coil and the rest of the cabinet), so that the net momentum change is zero. This would occur even if it were in a vacuum.[/quote]Sir Isaac and myself are in complete agreement. When the cone moves back and forth it alternately pressurizes and de-pressurizes the surrounding air. Said pressurization and de-pressurization causes your eardrums to move back and forth in reaction; that's how we hear. Said pressurization and de-pressurization also causes the floor to move, how much being a property of the stiffness and mass of the floor. If the floor was vibrating in reaction to the walls of the speaker vibrating said cabinet walls would have to be moving as far as the cone does.

Edited by Bill Fitzmaurice
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