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Old 30th December 2002, 07:14 PM   #81
dhaen is offline dhaen  Europe
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Quote:
I sometimes feel something strange after a bottle or so.
So do I
Then I shut down my workshop and re-join the world until the effect wears off
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Old 2nd January 2003, 08:33 PM   #82
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For some additional info on "breadboarding" you may search through these sites

www.audio-consulting.ch

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Old 5th January 2003, 11:39 PM   #83
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Default First Live Experiment......

"Probably next sunday, I will get the chance to place springs under a mates bass rig and some pa cabs at a pub beergarden live show (rock/blues) and see what results we get."

That was yesterday, and we tried springs under his bass rig - 2 x very heavy cabs each containing 1x 12" & 1x 10" driven biamped by a Trace-Elliot amplifier (rated 500W rms total).
We placed the springs under the bottom cabinet, and the amplifier on top the upper cabinet.
The bass coupling into the stage was substantially altered, and the bass sound also.
The bass rig ran only the last 45 minute set arranged this way, and the concensus from the bass player and my companions in the audience was very much affirmative.
With altered bass rig eq, the result was really smooth, clean and nice bass, but with more attack, dynamics, clarity and fidelity.
This band is rock/blues 3 piece, all players are world class with 30 years experience, and they can really crank it up when they want to.
The pa was used only for vocals, elsewise stage sound provided the music.
From 15 m back, the soles of my shoes were buzzing on carpeted cement floor very nicely, and the bass had a 'rightness' that I have not heard before, and this enabled the drums and bass to 'sit' very nicely and naturally together.
Now if only I could get the guitar to turn down a bit.......

This is the initial experiment, and one night during the next week or so we will make better speaker cables, attack the cabinets and fit better wire and add some compensating RC networks, and then we should be really cooking.
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Old 5th January 2003, 11:51 PM   #84
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Default SPRINGLOAD

Howdy Eric,

Quote:
From 15 m back, the soles of my shoes were buzzing on carpeted cement floor very nicely, and the bass had a 'rightness' that I have not heard before, and this enabled the drums and bass to 'sit' very nicely and naturally together.
Have you considered springloading,say,the front of the cab with a pair of equidistant springs and using a decent (for the weight) spike at the rear?

It's just a thought...in that way the speaker,which puts out a lot of forward moving energy,would see a mechanical diode to ground whereas the rest of the cabs' bottom would be isolated from the stage floor?

May be worth the experiment?

Cheers,
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Old 5th January 2003, 11:59 PM   #85
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Default Not Yet......

Ummm, no I have not tried that yet.
When we get together one evening, there are a bunch of further little experiments to try, and a solid mount under the back of the cabinet may be one of them, but so far fully isolated by springs is working dandy.
How does a cone act as a mechanical diode ? - I have always been a little funny about this mechanical diode theory.

Eric.
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Old 6th January 2003, 12:56 AM   #86
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Default MECHANICAL DIODES

Hi,

For what it's worth:

SEARCH RESULTS

It is an engineering principal mostly used in building construction.

Basically a mechanical diode can be a spike or a conical element that acts as an electrical diode conducting (draining) energy one way and blocking in the other.

It works best when an uneven number is used ( one is usually best).

The pointy part faces downwards and drains energy away from whatever is resting on top and at the same time preventing energy to flow back up.
Due to to conical shape of its' top energy is dispersed there and has a hard time finding a point of entrance.
(much greater surface area)

By careful placement it can be quite effective and if you had,say,a set of three cones it can be quite an experience if you turn them upside down,move them around under the gear and so on.
It all makes an audible difference.

For use under speakers I find these very effective when the cone (or spike) facing downwards is put at the heaviest point.
Often this is close to where to magnet of the woofer is.

One can than draw an imaginary triangle and find the best spot to maintain equilibrium and the springs or spikes can than be put there for stability and further drainage.

On a stage this can be tricky since often cardboard floors are used that can well put out more energy than the woofer cabs,so some experimenting may be useful.

In your case the fixing of the heavy cabinet to its' underlying surface should give tighter bass and less return from the stage to the woofer cone.

A woofer launches its' throw forwards and the less it is disturbed in this motional plane the cleaner it will sound given a solid reference to ground.

So much for the theory.

Cheers,
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Old 6th January 2003, 01:02 AM   #87
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Default Re: Not Yet......

Quote:
Originally posted by mrfeedback
How does a cone act as a mechanical diode ? - I have always been a little funny about this mechanical diode theory.

Eric.
Hi, Eric,

The term "mechanical diode" seems to come up
most when talking about torque converters for
transmissions. It's supposed to prevent some
piece of rotating machinery from spinning back
the other way.

The spike is not really a "mechanical diode"
at all. Rather, it's a coupler.

Check out:
http://www.soundstage.com/maxdb/maxdb.htm

Erik
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Old 6th January 2003, 01:23 AM   #88
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Default ERIC>ERIK>FRANK

Hi,

Sorry to say so but that article conveniently ommits a number of physical principles where it seems to suit them best.

One always has to have a mass load of the supported device in proportion to vibration.
Be that airborne or structure born.

Isn't it obvious that when you put a lightweight object loosely on a set of cones it is not going to do any good?
Of course it is going to bounce and tremble around singing to its' own resonant frequency.

A bit too simplistic a view IMHO.

Cheers,
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Old 6th January 2003, 01:42 AM   #89
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Default Springs Are Not Directional......

"Using footers under the component still changes the sound you hear, not because the footer decouples better or is a more effective mechanical diode, but because you prefer the resonant signature of that footer to the stock feet."

Erik, thanks for your link, and that is my understanding already, entirely.

Frank, I have read and understood your points too.
I do not believe the diode principal attributed to cones, but I do well agree that the surface area of the cone contacting the cabinet is of great importance, and explained in the link given in the previous post.
In light of this, then a sonic difference is to be well expected according to the directions and placements of the cones, ands in accord with my previous experimentation.

"In your case the fixing of the heavy cabinet to its' underlying surface should give tighter bass and less return from the stage to the woofer cone."
The springs are providing near perfect isolation - the stage buzzing was due to acoustic coupling, and not mechanical coupling.
The cabinets used are VERY heavy, carpet covered and reasonably inert, and the overall sound was different, and to several peoples ears, much improved.
The comment from the bass player was that the sound was different to what he was used to, that he needed more playing time to get more familiar with it, and that his rig was more responsive, articulate and expressive, and that so far he LIKES it.
Anyway, the result of this experiment is very much encouraging, and in line with previous experimentation with domestic cabinets.

I still cannot believe that no one has bothered to try springs yet, despite my suggestions and results.
Is everybody still mesmerised by rort, folklore and convention ?.

Eric, The Trendsetter.
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Old 6th January 2003, 02:25 AM   #90
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Default PUDDING.

Hi,

Quote:
I still cannot believe that no one has bothered to try springs yet, despite my suggestions and results.
Eric,

As much as I would like to try it out my speakers just don't lend themselves to that kind of experiment at all.

Quote:
I still cannot believe that no one has bothered to try springs yet, despite my suggestions and results.
Yeah...surprises me too.Seems we have more listeners than do-ers.

In fact,I think where your idea appeals the most to me is when applied under a CDP and/or a DAC.
Since most of these aren't moving about by themselves a couple of low Q springs would be beneficial,I reckon.
Perhaps a felt srip in between the chassis and the springs?
And...I would still only use three of them.

Any guinea pigs?

Grand Master Alu Peter Daniel perhaps?

Cheers,
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